Scholarly article on Propionaldehyde 123-38-6 from Justus Liebigs Annalen der Chemie p. 61

Anaesthesia, 2002, 57, pages 284–313

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Correspondence

Use of methoxamine in the

resuscitation of epinephrine

resistant electromechanical

dissociation

may not be effective in restoring the we deﬁnitely need the government’s

blood pressure. However, as methoxam- backing and blessing to make any

ine has now been withdrawn from meaningful progress in this ﬁeld. In this

clinical use, other a agonists such as regard the Ôheavy biasÕ of NHS execu-

metaraminol or phenylephrine may be tives is welcome, especially if it means

Dr McBrien et al. describe three more readily available.

interesting cases of electromechanical

dissociation (EMD) resistant to epineph-

that there would be more money for the

service and a commitment to the im-

provement of the services to the pa-

tients.

F. M. J. Harban

rine treatment (McBrien et al. Anaes-

thesia 2001; 56: 1085–9). In these cases,

an a adrenergic agonist (methoxamine)

proved to be lifesaving. However, to

Queen Elizabeth Hospital,

Birmingham B15 2TH, UK

There is no pleasure without pain –

so we suppose that we cannot ignore

that comprehensive critical care is a

package that comes with a number of

recommendations and ÔOutreach Crit-

ical CareÕ is one small aspect of it. The

service is to be developed with the

following three essential objectives: to

avert admissions, to enable discharges

and to share critical care skills; we feel that

the latter is the most important aspect of

the package. We are not sure how the

acute pain team evolved, but it was

probably similar to how the intensive

care services evolved in this country, i.e.

Reference

1 European Resuscitation Council

Ôconsider an a agonist for any case of

cardiac arrest secondary to electro-

Guidelines 2000 for Advanced Life

Support. A statement from the

mechanical dissociation which is unres-

ponsive to epinephrineÕ may not be

Advanced Life Support Group and

approved by the Executive Committee

of the European Resuscitation Council.

Resuscitation 2001; 48: 211–21.

appropriate. These cases involved a

speciﬁc situation where the likely cause

of hypotension was a fall in the systemic

vascular resistance (SVR). This occurred

as a result of proven type 1 hypersensi-

tivity in two cases and direct action of

methylmethacrylate cement in the other. Outreach critical care services

Clearly in this case, an a agonist is a

logical choice. The Advanced Life We read with interest the editorial: ÔThe based on historic legacy and ad hoc

Support guidelines are designed to cover acute pain service: a model for outreach development, led by a few anaesthetists

a wide range of differing conditions for critical careÕ (Counsell. Anaesthesia 2001; who were interested.

use by practitioners of differing experi- 56: 925–6). We would like to make a

As advanced level trainees, we have

ence who may or may not be aware of the few observations regarding this. Just as been to local and regional meetings for

originating event. Indeed, hypotension the publication of ÔPain After SurgeryÕ led the introduction of the outreach servi-

causing EMD may be as a result of cardiac to the development of the acute pain ces as a part of our management train-

tamponade, tension pneumothorax or service, the Department of Health has ing. We are convinced that the

hypovolaemia. It is unlikely that the use commissioned Comprehensive Critical experiences of the acute pain services

of a agonists would be helpful in these Care – a review of adult critical care services have been considered in the planning of

situations. It would seem prudent to as a response to the Audit Commission’s the ÔOutreach ServicesÕ. The main pit-

continue to use epinephrine as the ﬁrst report ÔCritical to SuccessÕ. Indeed, it is the falls previously or still being experi-

line treatment for an EMD cardiac arrest ﬁrst time that there has been a review of enced with the acute pain services are

and to advise using an a agonist in cases of critical care services in the UK. With the being avoided. In this aspect there is a

hypotension where reduced SVR is NHS being a monopoly, at least as far as push to educate the ward staff and

suspected as the cause when epinephrine critical care services in this country goes, junior doctors about management of ill

All correspondence should be addressed to Professor M. Harmer, Editor of Anaesthesia, Department of Anaesthetics, University of

Wales College of Medicine, Health Park, Cardiff CF14 4XN UK.

Letters (two copies) must be typewritten on one side of the paper only and double spaced with wide margins. In addition, please

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degree and diploma of each author must be given in a covering letter personally signed by all the authors.

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284

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Correspondence

patients and patients with a potential to

deteriorate rather than Ôopen a veritable

PandoraÕs Box’. The introduction of

early warning scores (e.g. MEWS) and

the ALERT course [1], which is now

evolved and running in many hospitals,

should be able to take the pressure off

the critical care services, at least in the

long run. Time will tell whether Crit-

ical Care Outreach teams will do an

equal, lesser or better job in this role

than the Acute Pain teams. Compre-

hensive critical care outreach service is a

24-h, 7-days a week service, unlike the

acute pain service, which is a 9–5,

Monday to Friday service in almost all

hospitals we have worked in. At the

most unsocial time the Ôacute pain (ful)

babyÕ is left to be attended by a

surrogate. An important point in this

debate has been overlooked. Acute pain

teams are involved almost exclusively

with surgical patients. Their usefulness

in helping manage sick medical patients

are very limited, a large proportion of

admissions to ICU being ÔmedicalÕ. We

see no problem in the possibility that

there may be two teams potentially

reviewing the patients. If nothing else,

this gives sick patients Ôtwo bites of the

cherryÕ in terms of chances that prob-

lems will be detected soon enough to

beneﬁt them. Ideally, the Acute Pain

Service in a hospital would work

alongside the Critical Care team in

wards contributing in their areas of

undoubted expertise.

We suppose we are in a world of

fantasy, as we foresee that the acute pain

teams will have to be amalgamated

within the outreach service. There

would be no point and it would be

extremely expensive to run two teams.

The expert group which reviewed adult

critical care services was determined

that their proposals should describe a

service which would meet the needs of

patients and be delivered by professions

and specialities working in partnership

and says Ôsuccessful implementation de-

pends on breaking down the barriers

between specialities and professions to

focus on the needs of the patientÕ [2].

ments such as X-ray and have supervised

the hospital-wide implementation of

Entonox and supported the dissemin-

ation of its use into community practice.

Recognizing the poor standards in key

areas of practice, they have facilitated the

introduction of standardised regimens for

postoperative antiemesis, postoperative

oxygen and more recently undertaken

initiatives to improve peri-operative

ﬂuid management. These include the

introduction of new pre-operative

ﬂuid ⁄ starvation guidelines and the

standardisation of pre- and postoperative

ﬂuid regimens. Over the years, the

service has established the principle of

direct referral of sick patients to Inten-

sive Care by acute pain nurses. This was

achieved long before the publication of

ÔComprehensive Critical CareÕ, despite

initial opposition from a number of the

intensive care consultants. Clearly, a

service such as this has much experience

of value when planning a hospital wide

service such as ÔOutreachÕ and whilst I

accept that not all APS have developed

to quite this degree, all have a great deal

to offer for the reasons outlined in my

original article.

To my mind the ÔoutreachÕ recom-

mendation is the most important aspect

of the document, not as you suggest a

Ôsmall partÕ. It is this initiative, if as a

profession we can get it right, that could

ultimately beneﬁt the most patients. Is it

enough to rely on MEWS and ALERT

simply to avert the tide of new referrals to

ICU, which I doubt they will do, or

should we be trying to do more? Surely,

it is better to prevent physiological

deterioration from occurring in the ﬁrst

place. Comprehensive Critical Care fails

to address this issue. In my experience,

intensive care physicians are quick to

criticise the poor ﬂuid management, lack

of oxygen or analgesia that has led to a

patient’s deterioration, yet they have

little concept of how and why these

problems occurred or as to how they can

be avoided. Above all else, it is this insight

that Acute Pain Services has to offer.

So what of MEWS and ALERT in

which Drs Prasad and Acharya put so

much faith? To date, early warning

systems have only been validated on

surgical wards and more recently on a

medical admissions unit [1]. I am only

References

1 ALERT – Acute Life-threatening

Events – Recognition and Treatment.

A multiprofessional course in the care of the

acutely ill patients -School of Postgraduate

Medicine. University of Portsmouth.

2 Department of Health. A review of

adult critical care services. Comprehen-

sive Critical Care. May 2000.

A reply

Clearly, the need for a review of critical

care services has been long overdue.

There is a need for the involvement of

NHS executives in order to empower

the ﬁnancial backing to allow improve-

ments to take place, but the question of

balance remains a key issue. Would a

broader representation of clinicians have

led to a more balanced perspective?

Certainly on the issue of the objectives

of ÔOutreach Critical CareÕ I think it

would have.

From what I can ascertain, the only

direct input from an ÔAcute PainÕ prac-

titioner in the North-west has been the

involvement of a nurse practitioner at

the zonal meetings in the Preston

(which includes Blackpool) area. I am

unaware of any involvement beyond

this. How then can the experiences of

acute pain have been fully considered as

claimed?

The comments of Drs Prasad and

Acharya show a naive lack of insight

into what Acute Pain Services (APS)

have to offer and what they have

achieved: a naivete´, I suspect, that is

sadly reﬂected more generally amongst

intensive care physicians. As a case in

point, let us look brieﬂy at the achieve-

ments of one of the Acute Pain Services

in the North-west.

Beginning largely as a postoperative

service, they have spread over the past

10 years to include support for patients

in pain in many areas across the hospital

including paediatrics, accident and

emergency and medicine. They have

supported the use of acute pain tech-

niques when required in medical and

palliative care settings including home

epidurals and have provided multi-

disciplinary teaching programmes in all

settings to support these initiatives. They

have introduced improvements in the

management of incident pain in depart-

C. V. Prasad

D. Acharya

Blackpool Victoria Hospital,

Blackpool FY3 8NR, UK

Ó 2002 Blackwell Science Ltd

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Disposable laryngoscope blades

aware of one hospital that has so far APS other than to attend sick patients

implemented a system onto general ﬂagged up and referred by the pain

medical wards, and that only recently. nurses. This seems a sad omission when

On a national basis the lid has, as yet, the service has so much to offer. Acute

only been partially removed from ÔPan- Pain Services have to date been at the

doraÕs Box’, so perhaps one should forefront of critical care at ward level and

temper one’s optimism. The value of I do not believe therefore that Intensive

education alone in changing practice has Care have a monopoly view on the

been questioned [2] and therefore the issues. If they want that monopoly, then

potential impact of the ALERT initiat- it is incumbent upon the speciality to

ive warrants consideration. Although include training in outreach develop-

ALERT has all the appearances of Ôa ment for SpR’s. With outreach services

good ideaÕ, there is no evidence, in these as yet non-existent or in their embryolo-

days of evidence-based practice, that the gical state, training and insight can only

course has any impact on the standard of be gained by spending time with the

care on the wards or that it will help to more established Acute Pain Services.

Further to recent correspondence [1–4]

on the hazards of prion-related diseases

and the hazards encountered when

using new disposable surgical equip-

ment [1], we would like to report our

experience with the use of new dispo-

sable anaesthetic equipment. Recent

concerns regarding the possibility of

transmission of prion-related diseases

following the use of re-usable laryngo-

scopes [2, 3] have stimulated the trial of

various single use laryngoscope blades

or blade covers.

Recently, we were asked to use two

such blades from one supplier (Lite-

BladeTM II blades 1 and 2, Truphatek

International Ltd) during the course of

our anaesthetic list. We found that the

curved infant blade (blade 2) offered

little or no view of the larynx and very

little room for manoeuvre in the

mouth. When a re-usable Macintosh

infant blade was used, laryngoscopy was

performed without difﬁculty. The blade

was compared with our standard equip-

ment (also made by Truphatek); it could

be seen that cross sections of the blades

were very different in shape (Fig. 1), the

disposable blade having no oblique

proﬁle where it would have been in

contact with the tongue. In addition,

the portion of the blade which would

have been in the mouth during laryng-

oscopy was much larger (Fig. 2). The

result was that the blade did not curve

around the tongue. This signiﬁcantly

reduced the unoccupied area of the

mouth and pharynx when the blade was

inserted compared with the similar

re-usable blade. In the small infant’s

mouth this reduction in area prevented

a good view of the larynx. We were

therefore not satisﬁed with the per-

formance of the disposable curved

reduce the need for ICU. Given the

Like Intensive Care, Acute Pain

expense both in time and money of Services have grown in an unco-ordi-

running these courses for small groups of nated fashion and mistakes have been

students, such evidence is badly needed. made. If the outreach initiative is to

I have taught on ALERT for the past have its maximum effect quickly there is

6 months and it is clear that the package a need to widen the debate about its

has its problems. Some of the lectures are remit and to establish effective, well

poor and a number of the slides are thought out services, otherwise the

unintelligible. Timing of the lectures, mistakes of the past will be repeated.

particularly to junior medics, is crucial Many people like myself in the acute

due to the rapid turnover of staff.

pain ﬁeld have been striving for years to

The provision of 9–5, Monday to improve general standards of care on the

Friday, Acute Pain Services has nothing wards with little support from policy or

to do with convenience as implied and ﬁnance. We admit to some frustration

everything to do with funding. Most that now monies are available our

services (the one outlined earlier being a efforts, advice and potential contribu-

good example) strive to improve cover tions are being largely ignored. Our

to include early evenings and a part patients deserve the best quality service

service at weekends within existing possible and the NHS deserves the best

budgets where possible. The use of service for its investment. This is

other trained staff, e.g. from theatre achievable if we work together.

recovery or using a link nurse network is

D. J. Counsell

also organised to reduce unnecessary

Maelor Hospital,

calls to medical staff. The need for 24-h

Wrexham, UK

cover for both Acute Pain and Outreach

is the single most cogent ﬁnancial argu-

References

ment for why service co-operation is

essential. There should be no need for an

Ôoutreach nurseÕ to refer basic acute pain

problems, such as topping up an epidu-

ral, to a pain nurse. Multi-skilling and

co-operation are essential to provide the

sort of comprehensive service that is

required, and the model that I suggested

is, I believe, one way to achieve this.

So where in the North-west is the

exemplary Acute Pain Service outlined

above? Actually it’s at the Blackpool

Victoria Hospital, Drs Prasad and

Acharya’s own hospital. I suspect that,

as yet, they have had no dealings with the

1 Subbe CP, Kruger M, Rutherford P,

Gemmel L. Validation of a modified

Early Warning Score in medical

admissions. Quarterly Journal of Medicine infant blade.

2001; 94: 521–6.

Later, on a different patient, we tried

to use a disposable straight infant blade

from the same supplier (blade 1). Dur-

2 Bero LA, Grilli R, Grimshaw JM,

Harvey E, Oxman AD, Thompson

MA. Closing the gap between research ing laryngoscopy a small piece of green

and practice: an overview of systematic material, looking very similar to the

reviews of interventions to promote the material of which the laryngoscope

implementation of research findings.

The Cochrane Effective Practice and

Organisation of Care Review Group.

blade was manufactured, was seen in

the vallecula. This was removed using a

yankauer sucker (Fig. 3), prior to intu-

British Medical Journal 1998; 317: 465–8. bation. We can only assume that a

286

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Anaesthesia, 2002, 57, pages 284–313

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Correspondence

tial dangers of converting to new

equipment in the light of concerns over

repeated use equipment. Like those

incidents already reported [1, 5], there

have also been several problems with

the disposable ENT surgical equipment

in our trust. We agree with some of the

comments made in Anaesthesia News

[4, 5] cautioning against the hasty

change to disposable equipment. We

recognise that this change has been

made in an attempt to reduce a risk,

which may be signiﬁcant but is not yet

fully quantiﬁed. The change has already

led to critical incidents which, if repea-

ted could lead to morbidity or mortal-

Figure 1

been that the moulding process had left ity.

a small tag attached to the blade near the

S. Babb

light bulb (Fig. 5). If so, this was not

S. Mann

noticed during routine inspection. Had

The John Radcliffe,

the fragment been inhaled we do not

Oxford OX3 9 DU, UK

know whether it would have produced

a signiﬁcant inﬂammatory response or

whether it would have been clinically

or radiologically detectable. We do

References

1 Martin F, Wilde A. Tonsillectomy –

anaesthetic technique and the new dis-

believe that if detection and removal

posable surgical equipment. Anaesthesia

2001; 56: 912.

of the fragment bronchoscopically had

been necessary it would have been very

difﬁcult.

Our experience re-emphasises the

importance of quality control, the

checking of equipment, and the poten-

2 Lowe PR, Engelhardt T. Prion-

related diseases and anaesthesia. Anaes-

thesia 2001; 56: 485.

3 Arnstein F. New variant Creuzfeldt-

Jakob disease – is our practice safe?

Anaesthesia 2001; 56: 585.

4 Frerk C. Life is not risk free. Anaesthesia

News no. 167 June, 2001.

5 Allan B. Disposable danger. Anaesthesia

Figure 2

News no. 169 August, 2001.

A reply

As a leading manufacturer of all types of

re-usable and single use laryngoscopes,

we are always interested in discussing

with clinicians and taking into account

Figure 4

their particular likes and dislikes con-

cerning our equipment. Obviously, we

prefer to do this face to face rather than

in the public domain and our UK

Agents (Proact Medical Ltd, Kettering)

are always available to help in these

discussions. However, it should be

noted that our Lite Blade range of seven

blade sizes is very widely used in the

UK, USA and most European countries

and was ﬁrst made available in the UK

in 1994, many years before the current

move towards use of single use prod-

ucts. Overall, we are very pleased by the

Figure 3

fragment of the larngoscope blade had

fallen off. On re-examination of the

blade, a piece was missing where the

blade joined the laryngoscope handle

(Fig. 4), although the material removed

from the airway did not appear to be the

appropriate size or shape. It may have Figure 5

Ó 2002 Blackwell Science Ltd

287

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

wide appreciation of the single use their previous experience that it was cases with a median volume of 22 ml and

version including the strong light emis- impossible. We believe it likely that a a range of 0–85 ml. In none of the cases

sion, the rigidity of the blade and the similar belief is common around the was there any suggestion of clinical

variety of size options. On the other country. This lack of awareness had regurgitation or aspiration.

hand, we also accept the comments contributed to a less diligent checking

In a recent case in our intensive care

from other clinicians who have been of the vaporisers and reduced emphasis unit, a Pro-Seal was being used to allow

trained and have been very happy using on training those who ﬁlled them. A endoscopic guidance during a percuta-

our metal blade ranges for many years. similar problem with overﬁlling has neous tracheostomy. The patient had

With respect to these particular been described with older models and been nasogastrically fed and the stomach

clinicians’ views, we fail to see the led to a Safety Action Bulletin from the was aspirated before the procedure.

relevance of linking their comments on Department of Health in 1992 [2]. During dilation of the trachea, some

the shape of one of our blades to their There were also interesting discussions nasogastric feed was vented a consider-

reservations about the need to convert in the Canadian press around the same able distance out of the drain tube.

from re-usable to single use products, an time [3, 4]. Our incident has taught us Since the endoscope was at the glottic

issue worthy of discussion in itself.

an old lesson.

opening during this episode of regurgi-

tation, it was possible to conﬁrm, under

direct vision, that there was no laryngeal

or tracheal soiling.

D. Grey

Trumphatek International Ltd,

Netanya, Israel 42101

D. Daniels

St George’s Hospital,

London, SW10 0QT, UK

E-mail: ddaniels@doctors.org.uk

Large studies and meta-analysis has

suggested that the incidence of aspiration

of gastric contents when using a classic

laryngeal mask airway is approximately

0.05–0.009% [1, 2]. A recent editorial on

mechanical ventilation via the laryngeal

mask airway rather speculatively sugges-

ted that aspiration of gastric contents

might occur in up to 360 patients per year

in the UK [3] and implied that such

practice could not be considered entirely

safe. The choice of whether to use a

laryngeal mask airway when artiﬁcially

ventilating a patient varies considerably

in UK practice [4].If elective cases may

have signiﬁcant volumes of gastric ﬂuid,

and there is some doubt as to whether

ventilation via the classic laryngeal mask

airway is safe, then the Pro-Seal is likely

to be a valuable addition to the airway

armamentarium. Laryngeal seal pressure

is increased by approximately 50% [5]

and the drain tube allows easy and

reliable access to the stomach [5]. In

addition, the drain tube might be ex-

pected to vent gas leaking into the

oesophagus reducing gastric dilation,

although this is untested. Should regur-

gitation occur, the drain tube may allow

venting of regurgitated material and its

appearance in the drain tube may act as

an early warning.

Overﬁlling of vaporisers

References

1 Checklist for Anaesthetic Apparatus 2.

London: Association of Anaesthetists of

Great Britain and Ireland, 1997.

After reading recent correspondence

regarding a failure of an Ohmeda Tec

5 generation vaporiser (Fernando &

Peck. Anaesthesia 2001; 56:1009–10), I

was left with the impression that they

described a relatively freak event which

was unlikely to be repeated. However, a

recent event in our hospital revealed it

was relatively easy to overﬁll this gen-

eration of vaporisers without any tilting

at all. In fact, several of our vaporisers

were overﬁlled on the same evening.

This overﬁlling may be achieved simply

by loosening the ﬁller from the bottle

and ﬁlling with the vaporiser turned on,

manoeuvres that have been used to

speed the ﬁlling process. Despite our

staff being familiar with the current

recommendations of the AAGBI [1]

regarding checking anaesthetic equip-

ment, the overﬁlling was only noticed

when an oversupply of vapour (6.5%

when dialled to 1.5%) triggered an

alarm on the anaesthetic agent monitor.

Fortunately, this incident had no

adverse effect on our patient. However,

if the faulty vaporiser had been in one of

our anaesthetic induction rooms

without volatile agent monitoring, and

the patient had been less ﬁt, this may

not have been the case. This event

highlighted the fact that no-one in our

department was aware that these later

2 Department of Health. Anaesthetic

agent vaporisers fitted with agent spe-

cific fillers: reports of overfilling. Safety

Action Bulletin no. 82, 29 April 1992.

3 Sinclair A, Van Bergen J. Vaporiser

overfilling. Canadian Journal of Anaes-

thesia 1993; 40: 77–86.

4 Hardy JF. Editorial. Canadian Journal of

Anaesthesia 1993; 40: 1–3.

The Pro-Seal laryngeal mask

airway

We were interested in recent correspon-

dence relating to reﬂux of gastric con-

tents into the drain tube of the Pro-Seal

laryngeal mask airway (Dalgleish &

Dolgner. Anaesthesia 2001; 56: 1010).

As part of a trial comparing performance

of the Pro-Seal with the classic laryngeal

mask airway we inserted a gastric tube

into the drain tube of 30 Pro-Seal

laryngeal maskairways in elective surgery

patients. All patients were starved for 6 h

for solids and 3 h for ﬂuids. In all cases,

ﬁbre-optic examination of the drain tube

and the oesophagus below was underta-

ken before passage of the gastric tube. On

no occasion was gastric content seen in

the drain tube or in the upper oesopha-

gus. Gastric ﬂuid was aspirated in 29 of 30

However, these potential advantages

have not been rigorously examined and

it is therefore too early to be sure of the

role of the Pro-Seal in anaesthetic

practice. What evidence is there that

the Pro-Seal allows a greater margin of

safety in the event of regurgitation? At

generation

overﬁlled, with some convinced by

vaporisers

could

be

288

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Correspondence

a survey of clinical practice in the

United Kingdom. Anaesthesia 1999; 54:

72–6.

present there is little; we are aware of

three cases in which regurgitated matter

has appeared in the drain tube without

laryngeal or tracheal soiling (A. Brain,

Personal communication). Drs Dalgle-

ish and Dolgner’s report brings the total

to four, but is the ﬁrst to be published.

In addition, a study in cadavers [6]

supports the contention. A study, at

present only presented at a meeting, of

the use of the Pro-Seal for laparoscopic

cholecystectomy showed no more gas-

tric distension than with a tracheal tube

(Maltby JR, Beriault MT, Watson NC,

Liepert DJ, Fick GH. Laparoscopic

cholecystectomy: LMA-Proseal vs. tra-

cheal intubation. Poster presentation.

Canadian Anaesthesiologist’s Congress

2001, Halifax, Canada).

If we wait for a controlled study

between the two devices to give us the

answer, it will be a long wait. If the

incidence of aspiration during anaesthe-

sia while ventilating through the classic

laryngeal mask is 1 in 11 000 cases, as has

recently been suggested [3]and thisnum-

ber can be halved by using the Pro-Seal,

this would reduce the number of such

cases in the UK by 180 per year. Con-

ducting a trial to detect such a reduction,

however, would require approximately

1.3 million patients in each group.

istration of epidural medications inten-

ded for intravenous use, has led us to

consider various strategies that might be

taken to implement an alternative coup-

ling system for regional equipment. As

part of this process the development of a

coalition for change will be essential.

This should include the various medical

colleges and associations, hospital and

health authorities, manufacturers and

therapeutic goods administration bodies

as well as anaesthetists and other practi-

tioners involved in administering centro-

neuraxis medications (oncologists,

chronic pain personnel, haematologists,

intensive care physicians, radiologists).

Early involvement of national and

international regulators would be impor-

tant as they typically work to fairly rigid

agendas and long timeframes. Network-

ing will be equally important particularly

with and between interested political and

professional bodies or individuals with a

high political inﬂuence [5].

When considering alternative designs

for regional equipment, we should

ideally retain the positive basic properties

of the current system but with the

additional feature of incompatibility with

the standard luer ﬁttings. It is possible to

describe a set of properties for the ideal

regional coupling as set out in Table 1. It

is envisaged that the new coupling shall

constitute the interface between all com-

ponents associated with regional drug

administration, including epidural and

spinal needle hubs, ﬁlters, drawing-up

cannulae, minimum volume extension

tubing as well as syringes. In line with this

development, drugs for regional use

should be packaged in such a way that

only regional coupling systems could

access them. There have now been

severalsuggestionsofanalternativecoup-

ling system to the current luer standard

5 Brain AIJ, Verghese C, Strube PJ. The

LMA ÔPro-SealÕ – a laryngeal mask with

an oesophageal vent. British Journal of

Anaesthesia 2000; 84: 650–4.

6 Keller C, Brimacombe J, Kleinsasser A,

Loekinger A. Does the Pro-Seal laryn-

geal mask airway prevent aspiration of

regurgitated fluid? Anesthesia and

Analgesia 2000; 91: 1017–20.

Gum elastic bougies

There are two types of adult gum elastic

bougies, one with a kink, one straight

(Kumar & Jones. Anaesthesia 2001; 56:

1121). I prefer the kinked one for two

reasons.

First, if the larynx is very anterior the

kink helps upward insertion. Second,

when pushed right in, the kinked

bougie stops at ﬁrst or second genera-

tion bronchi, leaving 25 cm or so

sticking out of the mouth. The oeso-

phagus takes all 60 cm. The kink stops

you going too far down the bronchial

tree; lung laceration and pneumothorax

in a ventilated intensive care patient has

been reported, caused by a bougie [1].

W. F. S. Sellers

Kettering General Hospital,

Northamptonshire, NN16 8UZ, UK

T. M. Cook

J. P. Nolan

Royal United Hospital,

Bath BA1 3NG, UK

Reference

1 de Lima LG, Bishop MJ. Lung

laceration after tracheal extubation over

a plastic tube changer. Anaesthesia and

Analgesia 1991; 73: 350–51.

References

1 Brimacombe S, Berry A. The incidence

of aspiration associated with the lar-

yngeal mask airway: a meta-

analysis of published literature. Journal of Call for an alternative coupling

Clinical Anaesthesia 1995; 7: 297–305.

2 Verghese C, Brimacombe J. Survey of

laryngeal mask airway usage in 11 910

patients: safety and efficacy for conven-

tional and non-conventional usage.

Anesthesia and Analgesia 1996; 82:

129–33.

system for regional equipment

We have read with interest recent [1–3, 5, 9]. However, their relative

editorial comment and correspondence merits have yet to be established. It will

in both the anaesthetic [1–3] and gen- be essential to choose the most effective

eral medical [4, 5] press regarding the of any proposed solution, especially

need for system wide change separating when one takes into account the consid-

epidural and spinal equipment from the erable effort that will be required to

luer system. Recent deaths in the UK implement the modiﬁcations to regional

3 Sidaras G, Hunter JM. Is it safe to

artificially ventilate a paralysed patient

through the laryngeal mask? The jury is [6, 7] and Australia [8], together with equipment on the scale required [5].

still out. British Journal of Anaesthesia

2001; 86: 749–53.

4 Simpson RB, Russell D. Anaesthesia

serious critical incidents occurring in

We believe that all clinicians strive to

our own hospital, due to the adminis- provide the safest level of care for their

tration of an epidural infusion via the patients as a matter of basic principle

for daycase gynaecological laparoscopy: intravenous (IV) route and the admin- and for that reason alone this type of

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Correspondence Anaesthesia, 2002, 57, pages 284–313

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Table 1 Properties of the ideal regional equipment coupling.

Clinical features

Male and female ﬁttings shall be conical to facilitate a partial twisting action for connection and disconnection

Separation and coupling forces shall be similar to those for the conical taper of the luer system

All the components required for regional drug administration shall employ this coupling

Components with this connection shall be easily distinguished from i.v. components, e.g. colour coded

All regional components should be physically incompatible with intravenous equipment and vice versa

Technical characteristics*

Male and female conical ﬁttings shall have tolerances for maximum and minimum dimensions within 1%

Rocking of the conical coupling elements should not be evident

Liquid and air leakage should not occur

No evidence of stress cracking under conditions or likely to be encountered in clinical use

Production shall be with materials that are suitable for medical use, cheap and environmentally responsible

* As described in the International Standards (ISO 594, ISO 594 ⁄ 1).

New Zealand College of Anaesthetists

Bulletin 2001; 10: 5–6.

change should be embraced. However,

it is conceivable that when future

patient incidents occur, failure to

implement change in the knowledge

of the problem and the availability of

potential solutions could constitute a

serious medico-legal challenge.

surgical and anaesthetic problems

because of the physiological, anatomical

and pharmacological changes associated

with obesity. Problems may occur dur-

ing induction, intra-operatively and

postoperatively in the recovery room.

Both general and regional anaesthesia

may not be straightforward. Thus one

has to be prepared for the unforeseen

adverse incidents.

9 Cyna AM, Simmons SW, Osborn K,

Andrew M. Fatal epidural infusion –

call for a system wide change. Anaes-

thesia and Intensive Care (in press).

A. Cyna

S. Simmons

Obesity and day-case surgery

in an isolated unit

Women’s and Children’s Hospital,

Adelaide, SA 5005, Australia

E-mail: cyanaa@wch.sa.gov.au

The guidelines for day-case surgery

from the Royal College of Surgeons of

We read with interest, the article England are that patients who are

ÔObesity and day-case surgeryÕ (Davies grossly obese with a body mass index

et al. Anaesthesia 2001; 56: 1112–15). greater than 30 kg.m⁾²should be

The authors have mentioned that mor- excluded for day-case surgery [2]. We

bid obesity should not be used solely as also wish to mention another weight

an exclusion criterion for day-case sur- related selection criterion to be consid-

gery and patients should be considered ered, which is the maximum weight

for day-case surgery based on their carried by the operating theatre table.

References

1 Birks RJS. Safety matters. Anaesthesia

2001; 56: 823.

2 Lanigan C. Luer-lock epidural con-

nections. Anaesthesia 2001; 56: 586.

3 Laws D. The time has come for non-

interchangeability of spinal and epidural medical, physical and social conditions Most normal operating theatre tables

equipment with intravascular access and the type of surgery. Although these can only withstand body weight up to a

ports. British Journal of Anaesthesia 2001; criteria are important, we feel that one maximum of 23 stone (although some

86: 903.

should also seriously consider the loca- may withstand more than this) and there

tion of the day-case surgery unit. Most have been incidences where we have to

errors lies in redesign – not exhortation. day-case surgery units in district general postpone cases and a special operating

4 Berwick DM. Not again! Preventing

British Medical Journal 2001; 322: 247–8. hospitals are in the main hospital com- theatre table has to be ordered.

5 Bickford Smith PJ. Designing safer

medical devices requires financial and

political support. British Medical Journal

2001; 322: 548.

pound with facilities for overnight stay,

In the article, although the authors

access to high dependency unit services have mentioned that there is no signi-

and medical assistance immediately ﬁcant difference between the unplanned

available for the surgeon and anaesthet- admission rate and unplanned contact

ist when required. However, there may with health care professionals for

be a number of day-case surgery units patients with a body mass index greater

that are isolated with no access to these than 35 kg.m⁾²and body mass index

6 Laville S, Hall C, McIlroy AJ. Cancer

boy dies after doctors’ drugs blunder.

Electronic Telegraph, February 2001;

Issue 2083: http://www.telegraph.co.uk facilities. Although patient selection less than 35 kg.m⁾², the reasons for

7 Sapsted D. Patient died after being

injected with wrong fluid. Electronic

Telegraph, 2 May 2001; Issue 2168:

http://www.telegraph.co.uk

criteria for day-case surgery are becom- them are not mentioned. It would be

ing less rigid, selection of patients for interesting to know the reasons and

day-case surgery in such an isolated unit whether they are related to obesity.

should be more stringent [1]. Obese

Thus we wish to stress that not only

8 Harcourt V. Coronial warning after

fatal epidural infusion. Australian and

patients, although they are ﬁt and well the patient and type of surgery criteria are

pre-operatively, may give rise to various important, the location of the day-case

290

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Correspondence

surgery unit is also an important criter- on analgesia following endometrial mask airway. Cuff pressure exceeded

ion to be considered when selecting thermal ablation and one called the 100 cmH₂O in two thirds of patients

patients for day-case surgery. Although DSU for advice on her experience of in whom it was measured. Minor

there is no evidence that a body mass frequency following a cystoscopy. The complications occurred in 13% of cases.

index greater than 35 kg.m⁾²should ﬁnal patient contacted her General

In Mandal’s recent report of 50 cases,

solely be an exclusion criterion for Practitioner with some swelling of her the AMD could not be placed in one

day-case surgery, one should seriously neck, but with no difﬁculty breathing case, was removed because of airway

consider that criterion when consider- or swallowing, following a hysterosco- obstruction in ﬁve cases and required

ing patients for day-case surgery in an py; he prescribed an antihistamine and repositioning because of obstruction in

isolated unit. On the other hand, one the symptoms resolved.

could argue that day-case surgery, in the

We agree that staff may need to be but were not limited to, regurgitation in

ﬁrst place, should not be done in such more cautious when selecting patients two patients [2].

a further case. Complications included,

an isolated unit. We believe that there for surgery in an isolated DSU. How- After our opinions were communi-

may be a number of such isolated units ever, we could ﬁnd no evidence that cated to the distributors of the AMD

in this country.

obesity alone is a predictor of problems (but not necessarily because of them)

following day surgery. We agree that the device was removed from the

there may be other weight related criteria market and design modiﬁcations have

that may limit patient selection In our been made. A modiﬁed AMD is soon to

unit, as mentioned in our paper, the be available. To our knowledge there

maximum weight carried by our trolleys are no reports of evaluation of the

is l25 kg and we do not accept patients performance of the modiﬁed AMD. To

K. M. Ni

J. C. Watts

Burnley General Hospital,

Burnley, Lancashire BB10 2PQ, UK

References

above this weight for day surgery.

suggest that the AMD (in its previous or

current form) is either reliable or safe is

therefore untenable.

1 Ni KM, Watts JC. Day case surgery in

an isolated unit may require more

stringent selection of cases. Anaesthesia

2001; 56: 485–6.

K. Davies

Royal Devon & Exeter Hospital,

Exeter EX4 6DW, UK

T. Cook

J. P. Nolan

K. J. Gupta

2 The Royal College of Surgeons of

England. Guidelines for Day Case

Surgery. March 1992. London: The

Royal College of Surgeons of England.

K. Houghton

J. Montgomery

Torbay Hospital,

Torquay TQ2 7AA, UK

E-mail: jane.montgomery@

sdevonhc-tr.swest.nhs.uk

D. A. Gabbott

Royal United Hospital,

Bath BA1 3NG, UK

A reply

Thank you for the opportunity to reply

to Drs Ni and Watts’ letter. We do not

References

1 Cook TM, Gupta K, Gabbott DA,

Nolan JP. An evaluation of the Airway

Management Device. Anaesthesia 2002

(in press).

believe that our reasons for admission to The Airway Management Device

the hospital after surgery, or unplanned (AMD) is not Ôreliable and safeÕ

contact with health care workers, were

directly related to the patient’s obesity. The recent comments (O’Neil. Anaes-

Eight patients with a body mass index of thesia 2001; 56: 1010–11) should not be

greater than 35 kg.m⁾²were admitted; allowed to pass without further com-

of these three were for pain, one ment. Dr O’Neil states that a new

following an umbilical hernia repair airway device must be safe and reliable.

2 Mandal NG, Hebblethwaite R.

Experience with the airway manage-

ment device. An audit of 50 consecutive

cases. Today’s Anaesthetist 2001; 16: 67–8.

and two postendometrial thermal abla- No-one would disagree with this state- Nasal endoscopy prior to

tion. One patient had voiding problems ment: but his claim that the AMD, nasotracheal intubation

after a hysteroscopy, one patient felt which he invented, is such a device

ÔunwellÕ after the insertion of a pubo- is not substantiated by the available I read with interest the recent article

vaginal sling, one elderly gentleman was evidence. We audited 105 cases [1] (Coe et al. Anaesthesia 2001; 56: 447–

admitted for hypotension after the and were unable to establish an airway 50) that investigated whether there was

removal of a skin lesion and there was in 10 cases. In a further ﬁve, complete a difference in the incidence of com-

no reason recorded for the last patient. obstruction occurred during anaesthetic plications following nasal intubation,

Four patients with a body mass index of maintenance or recovery. Eight patients depending upon which nostril was

greater than 35 kg.m⁾²had unplanned showed intermittent or partial obstruc- chosen. The total incidence of difﬁculty

contact with health care professionals. tion. In addition, the AMD required or failure to intubate either nostril was

One returned to Casualty for a pressure more manipulation to establish an air- 24% (31 patients). The incidence of

dressing to be applied to the wound of way, and more manipulation during bleeding following nasal intubation was

an umbilical hernia repair, one called anaesthesia than observed in other com- 26% overall (33 patients) of which 9%

the day surgery unit (DSU) for advice parable papers studying the laryngeal (11 patients) had severe bleeding.

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Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

Although there was no signiﬁcant dif- it as a guide to insertion of the Pro-Seal researchers studied this method formally

ference in the incidence of complica- laryngeal mask airway^TM(PLMA^TM) [1]. and conﬁrmed its reliability [3, 4]. The

tions between the left and right nostril This technique is quick and simple use of a capnograph not only reliably

groups, the overall complication rate using the following steps: The distal end detects inadvertent insertion of a tube

was clinically signiﬁcant.

of the PLMA^TMdrainage tube is lubri- into the airway but also shortens the

In the study, the authors made a cated by squeezing a water-based gel time needed for correct insertion com-

clinical assessment of nostril patency into it; the drainage tube is threaded pared with the two-step radiological

followed by blind insertion through over the bougie until it protrudes from method [3].

either the left or right nostril. However, the proximal end; the PLMA^TMis

Radiography is the most reliable

clinical assessment of nostril patency is railroaded along the bougie, either method, but is not foolproof [5]. One

highly unreliable and misleading [1]. following the palatopharyngeal curve major theoretical advantage of the use

Blind nasal insertion results in a high using the index ﬁnger, or more directly of a capnograph over radiography is

incidence of complications, especially using a laryngoscope; the cuff is then that capnography can minimise pneu-

epistaxis. This is not surprising as a high inﬂated and ventilation commenced.

proportion of patients presenting for Our combined successful experience tion of

mothorax caused by inadvertent inser-

feeding tube into the

a

nasal intubation have signiﬁcant intra- of the bougie-PLMA^TMtechnique in intrapleural space [1, 2]. A capnograph

nasal deformities, even though they give 25 consecutive elective cases suggests is attached to a feeding tube at the point

no history of nasal obstruction and that the bougie not only helps guide the when the feeding tube is inserted at a

when both nostrils appear patent on PLMA^TMinto its correct location, but depth of about 25 cm (when the tube

clinical examination [2]. In my experi- also reduces impaction at the back of does not reach the bronchi or lungs). If

ence, performing a preliminary ﬁbre- the mouth. The technique can be carbon dioxide is detected, the feeding

optic nasal endoscopy enables the practiced on routine cases provided tube is removed and penetration of the

diagnosis or exclusion of intranasal there is no known oesophageal pathol- pleura can be avoided [1] Alternatively,

abnormalities and allows the selection ogy. It may also be useful backup a small-bore tracheal tube is inserted

of the most patent nostril for intubation. technique if the PLMA^TMbecomes into the oesophagus, and after the

This results in fewer complications and folded over during insertion [2].

I would therefore recommend this

J. Brimacombe

absence of carbon dioxide waveform

is conﬁrmed, a feeding tube is advanced

through the tracheal tube into the

gastrointestinal tract [2]. I fully support

Dr White’s suggestion and I believe

that multiple methods, including cap-

nography and radiography, should be

used to detect migration of a feeding

tube into the airway and to minimise

pneumothorax.

approach to nasotracheal intubation.

A. Howath

S. Singh

Cairns Base Hospital,

Cairns 4870, Australia

Queen Elizabeth Hospital,

Birmingham Bi5 2TH, UK

E-mail: sukhbinder.singh@virgin.net

C. Keller

Leopold-Franzens University,

6020, Innsbruck, Austria

References

1 Smith JE, Reid AP. Identifying the

more patent nostril before nasotracheal

intubation. Anaesthesia 2001; 56:

258–62.

References

T. Asai

1 Brimacombe J, Keller C. The ProSeal

laryngeal mask airway. A randomised,

crossover study with the standard lar-

yngeal mask airway in paralysed,

anaesthetised patients. Anesthesiology

2000; 93: 104–9.

Kansai Medical University,

Moriguchi City, Osaka 570–8507,

Japan

2 Smith JE, Reid AP. Asymptomatic

intranasal abnormalities influencing the

choice of nostril for nasotracheal

intubation. British Journal of Anaesthesia

1999; 83: 882–6.

References

1 Asai T, Stacey M. Confirmation of

a feeding tube position; how about

capnography? Anaesthesia 1994; 49:

451.

2 Brimacombe J, Keller C, Berry A.

Gastric insufflation with the ProSeal

laryngeal mask. Anesthesia and Analgesia

2001; 92: 1614–15.

A more ÔfailsafeÕ approach to

difﬁcult intubation with the

gum elastic bougie

2 Asai T. Use of a tracheal tube and

capnograph for insertion of a feeding

tube. Anaesthesia 1998; 53: 93.

3 Kindopp AS, Drover JW, Heyland DK.

Capnography confirms correct feeding

tube placement in intensive care unit

patients. Canadian Journal of Anaesthesia

2001; 48: 705–10.

Capnography for feeding tube

placement

The gum elastic bougie is frequently

used to facilitate difﬁcult intubation, but

sometimes fails due to oesophageal 2001; 56: 1123) reported that capnog-

A

recent letter (White. Anaesthesia

placement. When this occurs, the bou- raphy is extremely useful for detecting

gie is either reinserted, or an alternative inadvertent insertion of a feeding tube 4 Burns SM, Carpenter R, Truwit JD.

airway management technique used. into the airway. I would point out that

We suggest another option: leaving this idea has been suggested already [1,

the bougie in the oesophagus and using 2] and recently two independent

Report on the development of a pro-

cedure to prevent placement of feeding

tubes into the lungs using end-tidal

292

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Correspondence

CO₂measurements. Critical Care

Medicine 2001; 29: 936–9.

has a longer neck and has no such plastic these to our attention. We can advise

ÔcageÕ (Fig. 7), and thus with as little as that, as a result of this feedback, we have

half of a complete turn, the outlet of the now sourced and validated a different

bag can become completely obstructed. non-latex bag for use in our range of

This has led to a number of incidents adult breathing systems. This new bag

within our trust including the unneces- will incorporate a longer plastic bag

sary replacement of a tracheal tube and, mount in its neck. We are in the process

on a separate occasion, a laryngeal mask. of introducing this new bag across our

5 Kiwak MG, McLoud TC, Dedrick

CG, Shepard JAO. Entriflex feeding

tube: Need for care in using it. American

Journal of Roentgenology 1984; 143:

1341–2.

adult breathing system range.

S. Boumphrey

Derriford Hospital,

Plymouth PL6 8DH, UK

A new cause of airway

obstruction

J. A. Roe

European Quality Assurance &

Regulatory Affairs Manager,

Pall Life Sciences,

I wish to inform colleagues of a poten-

tial cause of apparent airway obstruction

caused by a design fault in a reservoir

bag. This is caused by the twisting of the

neck of the rubber reservoir bag provi-

ded with the PAL Bain breathing

system. The resulting obstruction of

the outlet to the bag results in the

appearance of complete or partial air-

way obstruction when trying to hand

ventilate the patient.

Other reservoir bags, such as those

made by Intersurgical, have little or no

neck to the bag and have a plastic ÔcageÕ

(Fig. 6), which prevents outlet obstruc-

tion even with extreme twisting of the

bag However, the PAL reservoir bag

A reply

Portsmouth PO1 3PD, UK

The 2 L neoprene (non-latex) reservoir

bag referred to in the above letter is

used widely in our range of adult

breathing systems and incorporates a

plastic bag mount, to maintain patency,

in its neck. The vigilance and postmar-

keting surveillance systems that we

operate, as a requirement of the Medical

Devices Directive (93 ⁄ 42 ⁄ EEC), sug-

gests that the vast majority of users of

this bag do not experience the same

difﬁculties reported by Derriford Hos-

pital.

A new clinical sign during

one-lung anaesthesia: fact or

ﬁction?

Over recent years, there has developed

amongst anaesthetists a reluctance to be

open-minded about any clinical practice

that is not Ôevidence-basedÕ or not

widely accepted. In the area of one-

lung anaesthesia, for instance, one prac-

tice that is yet to be widely embraced is

the use of an ambient pressure oxygen

reservoir attached to the non-ventilated

lung [1, 2], even though the resulting

exclusion of atmospheric nitrogen will

almost certainly hasten lung collapse and

so facilitate thoracoscopic surgery. It

will very likely also reduce the risk of

arterial desaturation [3].

Nevertheless, we appreciate the users’

concerns and thank them for bringing

Another of the several suggested

beneﬁts [1, 4–6], is the ability to

identify gas leaking past the endo-

bronchial cuff of the double-lumen

tube. If the leak is large, the reservoir

bag will be seen to progressively ﬁll

with each inspiratory phase of single-

lung ventilation, but smaller leaks may

not be so immediately obvious. They

can, however, be identiﬁed by the

anaesthetist pressing an ear to the

surface of the reservoir bag and

listening for the characteristic high-

pitched sound of gas escaping past a

tight restriction [1].

Listening over the reservoir bag pro-

vides different information from that

obtained by listening over the respirat-

ory tubing connecting the mechanical

ventilator to the ventilated lung, a

clinical practice that was employed by

at least some thoracic anaesthetists of an

Figure 6

Ó 2002 Blackwell Science Ltd

293

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

6 Pfitzner J, Peacock MJ, Pfitzner L.

Speed of collapse of the non-ventilated

lung during one-lung anaesthesia: the

effects of the use of nitrous oxide in

sheep. Anaesthesia 2001; 56: 933–9.

Airway management of a child

with temporomandibular joint

ankylosis following otitis media

Although the incidence of difﬁculty is

comparatively low, failure to properly

manage the airway may be life threat-

ening during anaesthesia. Limitation of

full mouth opening is one of the major

causes of difﬁcult tracheal intubation.

The temporomandibular joints (TMJ)

play a crucial role in mouth opening,

and disorders of them can cause prob-

lems to anaesthetists. We report the

anaesthetic management of a patient

with severe TMJ ankylosis following

otitis media.

Figure 7

era past. Here, the transmitted sound of only to ascertain whether or not a small

air moving freely in and, more import- gas leak occurring past a bronchial cuff

antly, freely out of the endobronchial really does sound like a Ôtight fartÕ.

A 3-year-old, 12.8 kg girl presented

for surgical release of ankylosis of the

right TMJ. She had a past medical

history of incision and drainage of

cellulitis of the face caused by otitis

media at 8 months of age. At that

operation, no limitation of mouth

opening or TMJ abnormality had been

seen, but immediately following the

operation the patient developed a lim-

ited ability to open her mouth. The

reduced oral opening and difﬁculty in

chewing resulted in growth retardation.

On admission to our hospital, physical

examination showed a maximal mouth

opening of 2 mm. Pre-operative 3-D

computed tomography revealed signiﬁ-

cant deformity and hyperplasia of the

right mandibular condyle, which was

ﬁxed to the glenoid fossa.

apparatus and large airways is reassuring,

J. Pﬁtzner

as is the absence of wheezy or rattly

The Queen Elizabeth Hospital,

noises.

Adelaide, South Australia 5011

In spite of the fact that listening over

the ventilator tubing during one-lung

References

1 Pfitzner J, Peacock MJ, Daniels BW.

anaesthesia provides useful clinical

information to an older anaesthetist

Ambient pressure oxygen reservoir ap-

such as myself, very few younger

anaesthetists seem prepared to consider

that simple auditory signs might provide

information additional to that provided

lung anaesthesia: response to questions

by today’s sophisticated monitoring

equipment. To me, a particular change

in monitored pressure-volume loops

might suggest either a recent shift in

position of the double-lumen tube or a

recent accumulation of bronchial secre-

tions, whereas listening over the venti-

paratus for use during one-lung anaes-

thesia. Anaesthesia 1999; 54: 454–8.

2 Pfitzner J, Carne HD, Taylor EC. One-

on the ambient pressure oxygen reser-

voir. Anaesthesia 1999; 54: 1023–4.

3 Baraka A, Lteif A, Nawfal M, et al.

Ambient pressure oxygenation via the

non-ventilated lung during video-

assisted thoracoscopy. Anaesthesia 2000;

55: 602–3.

4 Pfitzner J, Peacock MJ, Tsirgiotis E,

On the day of surgery, the patient

was premedicated with hydroxyzine

12.5 mg and atropine 0.1 mg intraven-

ously. Anaesthesia was induced with

sevoﬂurane in oxygen 100% with the

patient breathing spontaneously. After

conﬁrming the ease of mask ventila-

tion, the concentration of sevoﬂurane

was increased to 5%. On attempting

intubation, the mouth could not be

opened more than 2 mm. We therefore

decided to try transnasal intubation

lator tubing will usually indicate which

of the two is causing the change.

Walkley IH. Lobectomy for cavitating

Perhaps the bending over to listen is a

lung abscess with haemoptysis: strategy

worry!

for protecting the contralateral lung and

With regard to these two different

also the non-involved lobe of the ipsi-

ear-pressing exercises, it must be said

that listening over the oxygen reservoir

bag is not as generally useful during

lateral lung. British Journal of Anaesthesia

2000; 85: 791–4.

5 Pfitzner J, Peacock MJ, Daniels BW.

thoracic surgery as listening over the

Administering ambient pressure oxy-

ventilator tubing at a time when the

chest cannot be readily auscultated. Even

so, anaesthetists might be more tempted

to try the former in the ﬁrst instance – if

genation to the non-ventilated lung

during thoracoscopic surgery. Anaes-

thesia 2001; 56: 281–2.

using

a

broncho ﬁbrescope. After

294

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Correspondence

2 Olsson GL, Hallen B. Laryngospasm

during anaesthesia: a computer-aided

incidence study in 136 929 patients.

Acta Anaesthesiologica Scandinavica 1984;

28: 567–75.

increasing the sevoﬂurane concentra- mouth opening is less than 25 mm.

tion, lidocaine 4% was sprayed into the Aiello and Metcalf demonstrated that

right nostril. As the patient’s mouth when the mouth opening is less than

only opened 2 mm, we could not apply 25 mm, it is unlikely that any part of the

topical lidocaine 4% to the patient’s larynx will be visualised by direct

larynx. A well-lubricated uncuffed 4- laryngoscopy [1]. If the mouth opens

mm-OD tracheal tube was introduced less than 25 mm, transoral ﬁbreoptic

through the right nostril and positioned bronchoscopy-assisted intubation, trans-

in the nasopharynx. A 60-cm Olympus nasal ﬁbreoptic bronchoscopy-assisted

LF-p broncho ﬁberscope (Olympus intubation, tracheostomy, or blind nasal

Optical Co. Ltd, Tokyo, Japan) with intubation should be performed under

an external diameter of 2.2 mm was sedation or using general inhalation

threaded inside the tube. The ﬁbre- anaesthesia with the patient breathing

scope was advanced, the vocal cords spontaneously. In our case, as the

identiﬁed, and their surrounding struc- patient’s maximal mouth opening was

tures identiﬁed as intact. When we only 2 mm and the patient was 3 years

attempted to pass the tracheal tube old, we chose transnasal ﬁbreoptic

3 Mevorach DL. The management and

treatment of recurrent postoperative

laryngospasm. Anesthesia and Analgesia

1996; 83: 1110–1.

Evaluation of the Pneupac

Ventipac portable ventilator

in critically ill patients 1

We were very interested to read the

recent study (McCluskey et al. Anaes-

through the vocal cords, severe laryn- bronchoscopy-assisted intubation under thesia 2001; 56: 1073–81) and believe

gospasm developed and we failed to sevoﬂurane anaesthesia, with the patient that the authors have provided valuable

place the tracheal tube in the trachea. breathing spontaneously. We were also

Mask ventilation became difﬁcult, and prepared to perform an emergency changes in cardiorespiratory parameters

detailed information regarding potential

the oxygen saturation, measured by tracheostomy.

pulse oximetry (Sp ₂), decreased tran-

The incidence of laryngospasm dur-

siently to 70%. After performing a ing anaesthesia is reported to be particularly wondered whether it would

with portable ventilators. A few ques-

tions, however, occurred to us. We

O

bilateral superior laryngeal nerve block 8.6 ⁄ 1000 in adults and 27.6 ⁄ 1000 in not have been preferable to assess the

with mepivacaine 1%, ventilation by children [2]. Topical lidocaine, succi-

ventilator in the conditions in which it

nylcholine, and positive pressure venti- is most commonly used, i.e. during

facemask became easy and the SP

returned to 100%. The second attempt lation are the standard management of transfer of critically ill patients. The

O

2

at transnasal ﬁbreoptic bronchoscopy- laryngospasm. However, since our pa-

assisted intubation was successful. Dur- tient’s mouth opening was limited and

study evaluates the performance of this

ventilator when it is still. The authors

ing surgery, anaesthesia was maintained we needed to maintain spontaneous rightly acknowledge that there are

with oxygen in nitrous oxide and breathing, we could not use lidocaine many other factors that may cause

sevoﬂurane (end-tidal concentration of and succinylcholine. Mevorach demon-

deterioration in the clinical condition

2–3%). Muscle relaxation was main- strated that bilateral superior laryngeal during transfer. They do not, however,

tained with intermittent boluses of nerve block was useful for treating mention the possibility that the venti-

vecuronium. The surgical course was severe repeated postoperative laryngo-

lator performance itself may be affected

uneventful and the maximal mouth spasm [3]. We believe that laryngospasm by physical movement during transfer.

opening was 28 mm immediately after could have been avoided if a superior Perhaps the manufacturers can demon-

surgery. After being trained to open her laryngeal nerve block had been per-

mouth, the patient was discharged on formed before attempting intubation in

the 30th postoperative day. Examina- our patient with limited mouth open- that considerable technical difﬁculty

strate that the ventilator performance is

not affected by motion. We appreciate

tion showed a maximal mouth opening ing.

of 30 mm.

would accompany the attempt to assess

this equipment during transfer, partic-

ularly using the very careful and thor-

ough method adopted by McCluskey

and colleagues. However, it might be

possible to achieve during intrahospital

transport such as from ICU to CT scan.

In addition, it would probably require

the use of continuous cardiac output

monitoring, rather than thermodilution.

The second question that occurred to

us concerned patient selection. They

described use of the ventilator in cases

with an appropriately wide variety of

clinical conditions, including very sick

patients (13 of 20 cases having a

T. Kawasaki

In this case, otitis media caused

arthritis of the TMJ, and as the infection

developed, bony adhesions occurred on

the TMJ causing true ankylosis. There

are three mechanisms by which otitis

media can cause ankylosis: primary otitis

media causing secondary joint involve-

ment; suppurative arthritis of the TMJ

involving the middle ear secondarily;

and suppurative arthritis of the joint,

T. Sata

C. Kawasaki

M. Ogata

A. Shigematsu

University of Occupational and

Environmental Health,

Kitakyushu 807–8555, Japan

References

which drains into the cartilaginous 1 Aiello G, Metcalf I. Anaesthetic

canal.

Conventional tracheal intubation

cannot be performed if the maximal

implications of temporomandibular

joint disease. Canadian Journal of

Anaesthesia 1992; 39: 610–16.

Ó 2002 Blackwell Science Ltd

295

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

PaO₂⁄ Fi

O

ratio of less than illustrated in the paper. Second, as the the decision of which ventilator to

200 mmHg). However, they imposed authors themselves state, the ventilator choose on this investigation.

2

the condition that patients must have was tested on an immobile patient and

M. Shamir

been stable for a period of 3 h. We felt therefore does not reﬂect the conditions

M. Peruansky

that there are occasions when unstable when used as a transport ventilator.

Hadassah Medical Center,

patients have to be transported, partic- More importantly, the Ventipac does

Jerusalem 91120, Israel

ularly where tertiary centre treatment is not meet the minimal requirements for

E-mail: shamir61@bezeqint.net

required (e.g. neurosurgery, paediatric a transport ventilator set out in the

intensive care) and that these will make guidelines for the transport of critically

up a signiﬁcant proportion of all use. In ill patients published by the American

these situations, the clinical condition College of Critical Care Medicine and

References

1 Guidelines committee of the American

College of Critical Care Medicine,

Society of Critical Care Medicine and

American Association of Critical Care

may be far from ideal but lifesaving the Society of Critical Care Medicine

treatment may only be available at the [1]. These guidelines suggest that a

receiving hospital. We have experience transport ventilator should be capable

of the Pneupac Ventipac ventilator in of delivering ventilatory modalities

such circumstances, in both adult and equivalent to those used in the intensive

paediatric cases, and have found it to be care unit. This would disqualify the gas

Nurses Transfer guidelines task force.

Guidelines for transfer of critically ill

patients. Critical Care Medicine 1993; 21:

931–7.

a highly reliable piece of equipment.

powered Ventipac as it will deliver

2 The Neuroanaesthesia Society of Great

Britain and Ireland, and The Associ-

ation of Anaesthetists of Great Britain

and Ireland. Recommendations for the

Transfer of Patients with Acute Head

Injuries to Neurosurgical Units.

December 1996.

Finally, we wondered whether the neither pressure support nor pressure

choice of ventilator mode was repre- control ventilation. Recently, the

sentative of normal case mix. All Association of Anaesthetists of Great

patients were ventilated in volume Britain and Ireland published recom-

control mode, yet in many circum- mendations for the transfer of critically

stances pressure-controlled ventilation is ill patients [2]. One major addition to

preferable. Patients requiring transport the American recommendations is the

are therefore sometimes converted from requirement for a delivered minute

pressure control ventilation to volume ventilation monitor, a feature the Vent-

control at the time of transport because ipac lacks. In a clinical review article,

of limitations of the portable ventilator. Wallace and Ridley suggested that

3 Wallace MW, Ridley SA. Transport of

critically ill patients. British Medical

Journal 1999; 319: 368–71.

We wondered whether the same car- equipment used for medical transport A reply

diovascular stability would have been should be battery powered and capable We would like to thank Drs Shamir,

demonstrated if the study periods on the of delivering variable oxygen concen- Peruansky, McNicholas and Harban,

standard ITU ventilator for some of trations, also properties the Ventipac for their interest in our article and are

these patients had been in pressure does not have [3]. In our experience, a grateful for the opportunity to respond

control mode.

ventilator like the Ventipac is not to the points raised. The Pneupac

optimal for the transport of patients Ventipac portable ventilator used in

with multisystem organ failure, especi- our study is a predecessor to the current

ally those with abnormal lung compli- model V200D, which incorporates an

ance and airway resistance, which additional integrated battery-powered

require ﬂexibility in ventilation tech- alarm system. The rationale for using

niques and close monitoring of ventila- the earlier model was that having com-

J. K. McNicholas

Portsmouth Hospital,

Portsmouth PO6 3LY, UK

F. M. J. Harban

University Hospital Birmingham,

Birmingham B15 2TH, UK

tory parameters during the transport.

prehensively evaluated its performance

Lastly, we feel very uncomfortable characteristics in a previous study using

with gas-powered transport ventilators. an artiﬁcial lung model and a group of

Unanticipated delays during transport, anaesthetised patients [1], we were

be it within a hospital (e.g. getting stuck reasonably conﬁdent that the ventilator

in an elevator) or between countries do would perform safely in critically ill

happen. With a gas-driven ventilator, patients.

Evaluation of the Pneupac

Ventipac portable ventilator

in critically ill patients 2

We read with great interest the Pneupac once the oxygen tank is empty, you

Drs Shamir and Peruansky state that

Ventipac assessment (McCluskey et al. will ﬁnd yourself without oxygen and the Pneupac Ventipac does not meet

Anaesthesia 2001; 56: 1073–81). We without ventilator. A battery-powered published recommendations for the

would like to address some methodo- ventilator may be a more ﬂexible transfer of critically ill patients [2, 3].

logical and conceptual problems.

Firstly, we could not identify which

alternative.

Ideally, a transport ventilator should

In summary, although the tested possess all of the features of a standard

ventilator was used. The Ventipac ventilator performed well, the testing intensive care ventilator and one could

V200D advertised on the Pneupac conditions did not adequately simulate argue that the only totally satisfactory

website looks different from the model patient transfer and we would not base solution is to use a standard intensive

296

Ó 2002 Blackwell Science Ltd

Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

Correspondence

3 Recommendations for the Transfer of

Patients with Acute Head Injuries to

Neurosurgical Units. The Neuroan-

aesthesia Society of Great Britain and

Ireland, and The Association of

Anaesthetists of Great Britain and

Ireland. London, 1996.

care ventilator attached to a ÔmobileÕ marily interested in observing changes

electricity source, which as we stated in these variables due solely to the

has been advocated [4]. The more transition from the standard intensive

additional features that are incorporated care ventilator to the portable ventilator

into a portable ventilator, the greater per se. Changes observed during trans-

becomes its weight, size, cost and port could have been due to a variety of

complexity (and the possibility of lower other factors, particularly disturbance of

reliability). The ideal portable ventilator the patient by motion. Second, as Drs

does not exist and a pragmatic choice McNicholas and Harban state, such a

has to be made based on a series of study would have been technically

4 Waydhas C, Schneck G, Duswald KH.

Deterioration of respiratory function

after intrahospital transport of critically

ill surgical patients. Intensive Care

Medicine 1995; 21: 784–9.

compromises.

much more difﬁcult and it seemed

Nearly all of our patients are paralysed prudent to limit the scope of this initial

and ventilated during transport and are study for that reason.

5 Wallace PGM, Ridley SA. Transport

of critically ill patients. British Medical

Journal 1999; 319: 368–71.

therefore managed safely and effectively

Drs McNicholas and Harban also

using volume control mode. We ﬁnd make a valid point concerning our

that patients in whom pressure control patient selection. We acknowledge in

ventilation is mandatory are usually not our article that an important limitation

sufﬁciently stable for transport. Thus, of our study was that unstable patients Aberrant brachio-cephalic

we consider pressure controlled and were excluded. Whilst recognizing that artery precluding placement

pressure support modes to be desirable transport of unstable patients is occa- of tracheostomy

rather than essential features of a trans- sionally necessary, the majority of trans-

port ventilator. Similarly, we do think fers take place only after appropriate A 56-year-old Afro-Caribbean woman

that continuously variable inspired oxy- resuscitation and stabilisation of the underwent an emergency evacuation of

gen fraction is an essential requirement patient. We also doubt very much that a posterior fossa haematoma following

of a transport ventilator. There is little our local ethics committee would have an acute cerebral haemorrhage. Post-

clinical advantage in setting a ventilator permitted our study to proceed if we operatively she spent 48 h in the Inten-

to deliver a precise oxygen fraction and had proposed to use the portable ven- sive Care Unit and after an uneventful

using 100% oxygen in patients requiring tilator in unstable patients.

more than 50% provides a useful ÔsafetyÕ

factor during transport.

extubation went to the Neurological

Finally, none of the points raised High Dependency Unit. Here she dem-

above detract from the primary aim of onstrated ﬂuctuating levels of conscious-

The Pneupac Ventipac is also criti- our study, namely to investigate the ness with a Glasgow coma scale (GCS)

cised by Drs Shamir and Peruansky for effects of a portable ventilator on inva- of 3–11. A subsequent CT scan showed

being gas-powered rather than battery- sively-monitored haemodynamic and evidence of hydrocephalus. Possible

powered. The article cited to support ventilatory variables in critically ill mechanisms of acute hydrocephalus in

this viewpoint features a Drager Oxylog patients. Within the acknowledged limi- posterior fossa injury are as follows:

¨

[5]. Whilst this ventilator does have an tations of our study, we feel it represents haematoma that extends to the supra-

integral battery, it serves only to power a useful ﬁrst step in this area of interest. tentorial area compresses the aqueduct

monitoring and display functions and to

control internal valves. Such a ventilator

is dependent on both electricity and

compressed gas, and will not operate if

either source fails. A transport ventilator

driven entirely by battery power inde-

posteriorly and causes hydrocephalus or

haematoma and contusional lesions may

directly occlude the fourth ventricle and

cause acute hydrocephalus [1]. This

made the decisions regarding Ôstep

downÕ difﬁcult. Whilst in the step down

unit, she suffered two episodes of aspir-

ation and was re-intubated and ventila-

A. McCluskey

C. L. Gwinnutt

E-mail: amccluskey@mcmail.com

References

pendently of a gas supply would be 1 McCluskey A, Gwinnutt CL.

limited to patients not adversely affected

by ventilation with 21% oxygen.

Clearly, our study group falls well

outside this requirement.

Evaluation of the Pneupac Ventipac

portable ventilator: comparison of per- ted in order to protect her airway. She

formance in a mechanical lung and

anaesthetised patients. British Journal of

Anaesthesia 1995; 75: 645–50.

made a good recovery from these epi-

sodes. Her short-term airway manage-

ment however, posed a problem.

While we agree with Drs McNicholas

and Harban that it would have been 2 Guidelines for transfer of critically ill

In view of the patient’s ﬂuctuating

level of consciousness and in order to

protect her airway from further aspir-

ation it was decided to perform a

useful to assess the ventilator during

patient transport, we decided to limit

our study to immobile patients for two

reasons. Firstly, there is so little data on

the effects of portable ventilators on

haemodynamic and ventilatory variables

of critically ill patients, we were pri-

patients. Guidelines committee of the

American College of Critical Care

Medicine, Society of Critical Care

Medicine and American Association of tracheostomy. In preparation for a per-

Critical Care Nurses transfer guidelines cutaneous tracheostomy a visual exam-

task force. Critical Care Medicine 1993;

21: 931–7.

ination of her neck was performed.

Although she appeared to have an

Ó 2002 Blackwell Science Ltd

297

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

anatomically easy neck, on palpation it careful visual and physical examination ity and spasm. It is thought to be

became apparent that she had a pulsatile of the neck when considering perform- immunological in origin [1] and is

mass lying directly across her trachea. ing a percutaneous tracheostomy. As associated with the production of anti-

The percutaneous route was aban- Muhammad et al. [7] conclude, the risk bodies against glutamic acid decarboxy-

doned.

of bleeding, although low, can be min- lase, the rate-limiting enzyme for the

In order to investigate more fully, a imised if the operator maintains a high synthesis of gamma-aminobutyric acid

CT scan of the neck was performed. This index of suspicion for aberrant vascular (GABA). Loss of inhibition from higher

demonstrated a 1.5-cm diameter aber- anatomy and investigates possible abnor- centres causes over-activity of the

rant brachio-cephalic artery overlying malities with diagnostic ultrasound.

the trachea. This vessel represented the

gamma motor neurone system and

subsequent progressive muscle rigidity.

We describe anaesthesia in a man with

Stiff–Person Syndrome who presented

with respiratory failure secondary to left

lung collapse.

G. A. Mukadam

only arterial supply to her right arm and

the right side of her head. A literature

E. Hoskins

London, UK

search has only revealed one paper that

describes a similar vessel [2]. Aberrant

arterial neck vessels have only been

described in children perhaps indicating 1 Karasawa H, Furuya H, Sugiyama K,

that such vessels are normally discovered

before adulthood [2–4]. Perhaps the

reason her aberrant vessel was not dis-

References

A 60-year-old man presented to the

Accident and Emergency department

et al. Acute hydrocephalus in posterior with respiratory deterioration following

fossa injury. Journal of Neurosurgery

1997; 86: 629–32.

treatment for a chest infection. He had a

4-year history of stiffness and spasms and

covered earlier is that her skin colour 2 Fournial JF, Stanley P, Fouron JC, et al. a diagnosis of Stiff–Person Syndrome

made it less visible to the casual observer.

As the percutaneous route had been

abandoned a request was made for a

formal theatre tracheostomy by the

Abnormalities of the aortic arch.

had previously been made. His efforts at

Apropos of 30 surgical cases in children. ventilation were severely impaired by

Archives Mal Coeur Vaiss 1975; 68:

485–95.

rigidity of his thoracic and abdominal

muscles.

In the Accident and Emergency

Maxillo-facial team. At a subsequent 3 Bertolini A, Pelizza A, Panizzon G, et al.

multidisciplinary meeting, the Maxillo-

facial surgeons concluded that the

potential late risk of erosion into the

vessel by a rigid plastic tube in a mobile

area was too great. The decision was 4 Chun K, Colombani PM, Dudgeon

made not to proceed with any form of

tracheostomy.

Vascular rings and slings. Diagnosis and department, his oxygen saturation on

surgical treatment of 49 patients. Journal room air was recorded as 86%. His

of Cardiovascular Surgery (Torino) 1987; arterial blood gases on high ﬂow oxygen

28: 301–12.

with a reservoir bag indicated a respir-

atory acidosis (pH 7.29, P

7.2, PCO

O

2

DL, Haller JA, Jr. Diagnosis and man-

agement of congenital vascular rings:

8.1, HCO₃28.7, BE 1.0). A chest X-ray

showed a ‘white out’ of his left hemi-

The patient continued to make a

a 22-years experience. Annals of Thoracic thorax and mediastinal shift. A diagnosis

Surgery 1992: 53: 597–602.

slow recovery with a ﬂuctuating GCS of respiratory failure secondary to left

between 3 and 12, having been suc- 5 Cooper RM. Use and safety of percu- lung collapse as a consequence of aspir-

cessfully extubated once again. How-

ever, despite slow progress she died

several days later due to a massive

pulmonary embolus.

taneous dilatational tracheostomy in

intensive care. Anaesthesia 1998; 53:

1209–27.

ation or secretion retention was made

and he was admitted to the Intensive

Care Unit.

Initial attempts at management with

non-invasive ventilation (CPAP of 6

cmH₂O) were unsuccessful and his

6 Hutchinson RC, Mitchell RD. Life

threatening complications from percu-

taneous tracheostomy. Critical Care

Medicine 1991; 19: 118–20.

Percutaneous

tracheostomy

has

gained acceptance as an alternative to

conventional surgical tracheostomy. A

arterial blood gases worsened (P

O 7.0,

2

recent postal survey of intensive care 7 Muhammad JK, Major E, Wood A,

PCO 10.2). A decision was made to

2

unit practice in the UK showed that

percutaneous tracheostomy was in use

in 78.4% of units [5]. Two methods are

currently widely used, the percutaneous

dilatation technique described by Cia-

glia and the guidewire dilatational

forceps technique. The Toye method

and the Rapitrac method have fallen

into disuse because of high mortality

rates [6]. Variations in the anatomy of

the neck can make percutaneous trach-

eostomy both difﬁcult and hazardous.

Perhaps the most important lesson to be

learnt from this case is the importance of

Patton DW. Percutaneous dilatational start invasive ventilation. At this point,

tracheostomy: haemorrhagic compli-

cations and the vascular anatomy of

the anterior neck. A review based on

497 cases. International Journal of Oral

Maxillofacial Surgery 2000; 29:

217–22.

no information was available regarding

which drugs were safe in this condition.

Anaesthesia was induced with mida-

zolam 1 mg and propofol 30 mg.

Atracurium 50 mg produced good

intubating conditions (Cormack and

Lehane grade

2 laryngoscopy) and

relaxation of axial and limb stiffness.

Following induction he was cardiovas-

cularly unstable requiring ephedrine

30 mg, metaraminol 5 mg and a subse-

quent norepinephrine infusion to main-

tain an adequate blood pressure.

Anaesthesia for Stiff–Person

Syndrome

Stiff–Person Syndrome (formally Stiff

Man Syndrome) is a rare neurological

condition characterised by muscle rigid-

298

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Anaesthesia, 2002, 57, pages 284–313

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Correspondence

Anaesthesia was maintained with fent- found no complication with the use of with oxygen in air, 1% isoﬂurane and

anyl (100 lg.h⁾¹

)

and midazolam a non-depolarizing muscle relaxant in had

a

remifentanil infusion at

(3 mg.h⁾¹). He was ventilated using this case.

BIPAP (P1: 20, P2: 5 ratio 1 : 1, rate 12

0.1 lg.kg⁾¹.min⁾¹. The isoﬂurane ana-

lyser recorded 0.5–0.7% end tidal con-

centration. The remifentanil infusion

was increased to 0.3 lg.kg⁾¹.min⁾¹and

isoﬂurane concentration increased to

5%. As we watched the monitors, we

noted that the vapour analyser showed

no increase in fractional inspired or end

tidal concentrations. The blood pressure

remained high and thereafter a bolus of

propofol was given, bringing the blood

pressure back to normal. The patient

came to no harm and had no recall of

events or dialogue postoperatively.

N. Haslam

breaths.min⁾¹) and his arterial blood

gases improved markedly (FiO of 0.45:

K. Price

2

Newcastle General Hospital,

Newcastle upon Tyne NE4 6BE, UK

E-mail: jahaslam@lineone.net

pH 7.38, P

26.7, BE 1.4, Sp

O 17.3, PCO 6.1, HCO₃

2 2

O 98%).

2

Fibreoptic bronchoscopy was per-

formed and copious amounts of puru-

lent sputum aspirated. Co-amoxiclav

1.2 g q.d.s and ﬂuconazole 200 mg

b.d. were commenced following

growth of yeasts and coliforms from

lavage ﬂuid. The patient’s respiratory

function gradually improved and he was

extubated and discharged to a high

dependency unit 72 h after intubation.

A second deterioration, 4 days after

his initial presentation, prompted a

second period of ventilation. This time

anaesthesia was induced using alfentanil

and propofol. Atracurium provided

muscle relaxation and intubation was

uneventful. He was subsequently

weaned from the ventilator once again

and eventually discharged to the ward.

Case reports in the neurology litera-

ture mention that patients with Stiff–

Person Syndrome have received anaes-

thesia for surgical procedures [2] and

periods of ventilation for respiratory

failure [3, 4] but no details of anaesthetic

management are reported.

Johnson and Millar [5] report a case

of hypotonia requiring overnight

ventilation after anaesthesia for repair

of an intrathecal baclofen pump in

46-year-old woman with Stiff–Person

Syndrome. Anaesthesia in this case was

induced with intravenous sufentanil

10 lg, thiopental 375 mg and vecuro-

nium 8 mg. The mechanism of the

resulting hypotonia was unclear,

although a subsequent return to thea-

tre for revision of the baclofen pump

was reported as uneventful. They

recommendedavoidanceorjudicioususe

of non-depolarizing muscle relaxants.

In our case, the patient remained

sedated to facilitate ventilation and

stiffness returned once the initial dose

of muscle relaxant had worn off.

Despite poor pre-induction posture due

to extreme rigidity, we obtained good

intubating conditions on two occasions

using atracurium for paralysis. We

References

1 Levy LM, Dalakas MC, Floeter MK.

The stiff–person syndrome: an auto-

immune disorder affecting neurotrans-

mission of gamma-aminobutyric acid.

Annals of Internal Medicine 1999; 131:

522–30.

On investigating the vaporiser, we

were unable to turn the vaporiser on

again after turning it off. We removed

and replaced the vaporiser, locked it

back into place and it turned on again

appropriately. We noted that previ-

ously, although not attached to the back

bar properly, it had been possible to

turn the vaporiser on. Some isoﬂurane

had also been detected by the vapour

analyser, so perhaps some volatile

anaesthetic had been added to the fresh

gas ﬂow; alternatively the isoﬂurane

detected could have been residual

vapour in the circle system.

Initially, we thought that the desﬂu-

rane vaporiser ﬂex which was lying

between the two vaporisers on the back

bar had simply interfered with the

isoﬂurane vaporiser ﬁtment and the

locking mechanism on the back bar,

thus causing the problem. Desﬂurane

vaporisers should sit on the back bar in

the most distal position, with its ﬂex on

its right. However, following a meeting

with the Datex-Ohmeda representative,

David Walker, we decided that the

reason for our problem was malposition

of the vaporiser. We were able to

illustrate that the leak test could be

perceived as negative, even if the

vaporiser was poorly ﬁtting and not

adding any agent to the fresh gas ﬂow,

despite seemingly being easy to turn on.

Occluding the fresh gas ﬂow outﬂow

caused the bobbins of the oxygen and

nitrous oxide rotameters to drop. We

repeated the test using Datex-Ohmeda’s

Low Pressure Leak Test Device [2] and

the poorly ﬁtting isoﬂurane vaporiser

was obvious.

2 Whelan JL. Baclofen in treatment of

the Ôstiff–manÕ syndrome. Archives of

Neurology 1980; 37: 600–1.

3 Meinck HM, Tronnier V, Reike K,

Wirtz CR, Flugel D, Schwab S. Intra-

thecal baclofen treatment for stiff–man

syndrome; pump failure may be fatal.

Neurology 1994; 44: 2209–10.

4 Stayer C, Tronnier V, Dressandt J, et al.

Intrathecal baclofen for stiff–man syn-

drome and progressive encephalomye-

litis with rigidity and myoclonus.

Neurology 1997; 49: 1591–7.

5 Johnson JO, Miller KA. Anaesthetic

Implications in Stiff–Person Syn-

drome. Anesthesia and Analgesia 1995;

80: 612–13.

Report of vaporiser malfunction

According to the Association of Anaes-

thetists of Great Britain and Ireland’s

(AAGBI) document of 1997 [1], a leak

test should be performed during the

anaesthetic machine check prior to

every operating list. This ensures proper

ﬁtment of vaporisers on the back bar

and excludes a leak from the vaporiser

with back pressure when the vaporiser is

in the ÔonÕ and ÔoffÕ position.

We encountered a problem while

anaesthetising a patient for an aorto-

bifemoral graft. We induced anaesthesia

in theatre having checked the anaes-

thetic machine as per the AAGBI

guidelines. Several minutes later, during

surgical preparation but prior to skin

incision, the patient’s blood pressure

rose. The patient was being ventilated

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Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

We conclude that the vaporiser was

ﬁtted wrongly on the back bar, and was

not detected despite two negative leak

tests. Consequently, should we not be

using more sensitive methods, such as

Datex-Ohmeda’s Low Pressure Leak

Device (see Fig. 8), during our anaes-

thetic machine checks and when

vaporisers have been removed for ﬁlling

or changed for a different vaporiser,

rather than relying on a very subjective

tactile method?

D. M. MacLeod

L. McEvoy

Grampian University Hospitals,

Aberdeen AB25 2ZD, UK

D. Walker

Datex Ohmeda

References

1 AAGBI. Checklist for Anaesthetic

Apparatus. London: Association of

Anaesthetists of Great Britain and Ireland.

March 1997.

2 Ohmeda. Operating Instructions. Low

Pressure Leak Test Device.

Up-and-down allocation

We would like to congratulate Dr

Palm et al. on their study quantifying

the ropivacaine sparing effect of suf-

entanil when both are combined for

epidural pain relief in labour (Palm

et al. Anaesthesia 2001; 56: 526–9).

They used the minimum local anal-

Figure 8

gesic concentration (MLAC) model [1]

to determine the effect of sufentanil on

the median effective concentration the strict assumptions that the data are plotted in both sequences do not really

(EC50) of epidural ropivacaine. It independent and randomly sampled. exist but shown only to identify that the

would appear, however, that they have Several approaches have been described previous data points were effective.

reported a spuriously low p < 0.00001 to deal with this problem, the Dixon There are better ways that these can

and tighter 95% conﬁdence intervals and Massey method being one of the be plotted such as the use of differing

than the data as presented in their more conservative approaches. For symbols for effective or ineffective tests

Fig. 1 suggest.

completeness we have included some or if necessary, a line that ends without a

A problem with the analysis of suggested corrections in Table 2 using point plotted on it showing the projec-

up-down sequences is that the obser- this method which we hope the au- ted direction of the sequence.

vations are not independent. Values thors and readers will ﬁnd useful, the

depend on the previous in the results still remaining signiﬁcant at the effects of oxytocin, something that

sequence. The simple estimation of p ¼ 0.046.

was raised in a metanalysis of some of

the medians (95% CI) using either the

Also, Fig. 1 may appear to be mis- the earlier MLAC studies [2]. On a

binomial or Wilcoxon approaches and leading in that there are n ¼ 22 subjects similar theme, Capogna et al. [3] in a

their comparison using such as

per group rather than n ¼ 21 as stated. modiﬁcation of the MLAC studies,

Mann–Whitney U-test are based on It is assumed that the last data points have shown that induction with

We look forward to their studies into

a

300

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Correspondence

Table 2 Amended results.

On day 3 of admission, our micro-

biologists had cultured a clostridium

from his buttock wound and this made

the diagnosis of botulism the most

likely. We proceeded to give antitoxin

and perform diagnostic bioassays for

serum toxins. These identiﬁed botuli-

num toxin A, the most common and

severe form of wound botulism [2].

We feel that we came to a deﬁnitive

diagnosis extremely promptly, given the

Minimum local analgesic

concentration (%w ⁄ v)

Group n ¼ 21

95% conﬁdence interval

Ropivacaine

Ropivacaine + sufentanil

0.128

0.094

0.117, 0.140

0.068, 0.120

Welch modiﬁed t-test: p ¼ 0.046 (95% conﬁdence interval of difference 0.001, 0.067).

Potency improvement: 1.36 (95% conﬁdence interval 1.01, 1.86).

prostaglandin was associated with a poppingÕ and Ômuscle poppingÕ, presen- very low incidence of wound botulism,

signiﬁcantly increased requirement for ted at our Accident and Emergency and this led to early anti toxin admin-

analgesia when compared to sponta- department. He gave a 3-day history of istration, which greatly improved out-

neous labour. Again the authors are to bizarre neurological symptoms inclu- come. Unfortunately, injection drug

be commended for using estimation ding ptosis, dysphagia and poorly use is a very real problem in our city.

rather than simple hypothesis testing in deﬁned limb weakness as well as anti- Comparisons must be drawn with this

continuing to research such effects.

cholinergic symptoms such as dry case and last year’s outbreak of severe

mouth and urinary retention. He had illness and sudden death from Clostrid-

an abscess at an injection site on his ium novyii among injecting drug users

right buttock. He had short episodes of [3], mainly from Glasgow, Dublin and

hypertension thought to be due to parts of England. These cases arose as a

autonomic dysfunction but a normal consequence of injecting heroin con-

Glasgow Coma Score, was apyrexial taminated with Clostridium novyii

and had normal blood biochemistry and spores and have made us more aware

haematology. He required intubation of the possibility of infection with

and ventilation shortly after admission unusual clostridial species in injecting

due to respiratory distress and had a drug users.

M. O. Columb

S. Maguire

South Manchester University

Hospital,

Manchester M20 2LR, UK

References

1 Columb MO, Lyons G. Determination

of the minimum local analgesic con-

centrations of epidural bupivacaine

and lidocaine in labour. Anesthesia &

Analgesia 1995; 81: 833–7.

lengthy stay in intensive care due to

respiratory failure and neuropathy.

There has been one other case of

wound botulism in Glasgow, which

On initial investigation of our occurred last year and a total of ﬁve

patient, we were faced with a differen- cases reported in the UK; all have

tial diagnosis that included intracranial occurred in injecting drug users.

infection, myasthenia gravis, Guillain– Recovery has been over a similar time

Barre´ syndrome and botulism. Our period of between 5 and 8 weeks,

deﬁnitive diagnosis came about partly requiring tracheostomy and prolonged

by exclusion of these other diagnoses. A weaning from ventilation. Ultimately,

CT scan of brain and lumbar puncture, full recovery looks likely in our case and

both of which were normal, ruled out it is thought that this has been due to

intracranial infection and helped to the prompt diagnosis and early admin-

exclude Guillain-Barre´. Anti-acetylcho- istration of antitoxin.

2 Columb MO, Lyons G, Polley LS,

Capogna G, Benhamou D. Minimum

local analgesic concentration of bupi-

vacaine in labour; Factors. Proceedings of

SOAP 1997; 124.

3 Capogna G, Parpaglioni R, Lyons G,

Columb M, Celleno D. Minimum

analgesic dose of extradural sufentanil for

first stage labour analgesia: A comparison

between spontaneous and prostaglan-

din-induced labours in nulliparous

women. Anesthesiology 2001; 94:

740–4.

line receptor antibody levels were neg-

ative, excluding myasthenia gravis.

World wide wound botulism has

been increasing among injecting drug

Nerve conduction studies showed users, particularly when the subcuta-

small amplitude compound muscle neous or intramuscular routes of injec-

action potentials without decrements tion are used. An epidemic of wound

in amplitude with repetitive stimula- botulism was described in California in

tion. This helped to further exclude 1998 [4] involving black tar heroin

myasthenia gravis. Needle EMG showed contaminated with spores of Clostrid-

Wound botulism in injecting

drug users

We read with interest the study of two small, short duration motor unit poten- ium botulinum. It was argued [5] that

cases of wound botulism in injecting tials with moderately reduced recruit- inoculation with Clostridium botulinum

drug users (Mulleague et al. Anaesthesia ment. This suggested that a disorder of spores occurred via soiled skin rather

2001; 56: 120–3). We present a recent, the neuromuscular junctions was more than from direct heroin contamination.

very similar case, occurring in Glasgow. likely than of the central nervous Obviously these two sources of clos-

A 33-year-old male heroin user who system. It was concluded at this stage tridium spores have different public

admitted injecting by the subcutaneous that our differential diagnosis was of health implications and if the heroin

and intramuscular routes known as Ôskin botulism or axonal Guillain-Barre´ [1].

itself contains spores then there is a

Ó 2002 Blackwell Science Ltd

301

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

potential for infection among other large number of crystals. Neither solu- be heavily crystallised. It is of course

users injecting from the same batch.

tion was administered to the patient, but impractical during transfers to redissolve

a clear, crystal free preparation of 10% these crystals by heating the solution to

Mannitol solution was used unevent- 60 °C and then waiting for it to cool.

L. McGarrity

Stobhill Hospital,

fully instead.

Additionally, there is insufﬁcient room

Glasgow, UK

E-mail: amcgarrity@freeserve.com

Both of the 20% preparations have in the rucksack for the necessary heating

clearly marked warnings on their labels, apparatus! As a result, this solution as well

advising the user to check for such as all 20% mannitol solutions within our

crystals immediately before use. Neither department have now been replaced

we, nor many of our colleagues were with 10% solutions. We can contemplate

aware of this potential hazard. The only very rare circumstances where a

potential for crystallisation is however, 10% solution could not be used in place

well documented in Martindale [1]. of a 20% solution. Furthermore, all

Mannitol solutions with concentrations mannitol solutions of whatever concen-

over 15% are supersaturated and there- tration must ﬁrst be visually inspected

fore particularly prone to crystallisation. and then if clear to the naked eye only

This propensity is increased when the administered through a suitable ﬁlter.

References

1 Maselli RA, Bakshi N. Botulism.

Muscle and Nerve 2000; 23: 1137–44.

2 Woodruff BA, Giffin PM, McCroskey

LM, et al. Clinical and laboratory

comparison of botulism from toxin

types A, B and E in the United States.

1975–88. Journal of Infectious Disease

1992; 166: 1281–6.

3 Christie B. Gangrene bug Ôkilled 35

heroin usersÕ. British Medical Journal

2000; 320: 1690.

solutions are stored below 20 °C. Mann-

A. Kitsberg

itol crystals can be redissolved by heating

J. A. J. Phillips

the solution to 60 °C, but should then be

Princess Alexandra Hospital,

4 Passaro DJ, Werner SB, McGee J,

MacKenzie WR, Vugia DJ. Wound

botulism associated with black tar her-

oin among injecting drug users. Journal

of the American Medical Association 1998;

129: 221–8.

ﬁrst cooled to body temperature before

Harlow CM20 1QX, UK

patient use. However, the presence of

microcrystals may still remain undetec-

References

1 Martindale –The Extra Pharmacopoeia

ted by visual inspection alone.

Rapoport [2] linked a high incidence

(31st edn).

2 Stanley I, Rapoport MD. Micro-

of microinfarction in one study to the

presence of mannitol microcrystals in

5 Bamberger J, Terplan M. Reply to

Wound botulism associated with black

tar heroin among injecting drug users.

Journal of the American Medical Association

1998; 280: 1479.

infaction: Osmotic BBB opening or

microcrystals in infusate? Journal of

infusates. Tomiwa et al. [3] reported

that preﬁltration of Mannitol solutions

Neurosurgery 1991; 74: 685.

3 Tomiwa K, Hazama F, Mikawa H.

through a 0.45 l-diameter ﬁlter pre-

vented infarct formation, whereas lar-

Reversible osmotic opening of the the

ger-pore ﬁlters did not. Furthermore,

blood–brain barrier. Prevention of

tissue damage with filtration of the

Not quite crystal clear

Losasso et al. [4] reported the detection

of mannitol crystals intravascularly by

perfusate. Acta Pathol Japan 1982; 32:

427–35.

Recently, it was necessary to administer changes in precordial Doppler tones

a solution of 20% Mannitol to a patient. that mimicked venous air embolism.

4 Losasso TJ, Muzzi DA, Cucchiara RF.

Doppler detection of intravenous

mannitol crystals mimics venous air

embolism. Anesthesia and Analgesia

1990; 71: 568–9.

A 500-ml Fresenius Kabi PolyfusorÒ

Both Fresenius Kabi and Baxter have

container of 20% Mannitol was located, been most helpful in supplying infor-

but it was noticed that the solution was mation with regard to this problem.

not totally clear. On closer inspection, a Firstly, they both recommend adminis-

considerable number of needle-shaped tering mannitol solutions through par-

crystals were clearly visible (Fig. 9). An ticulate ﬁlters (Baxter advises 20 l,

alternative solution was located (Baxter whereas Fresenius Kabi advises 5 l).

ViaﬂexÒ container of 20% Mannitol) Importantly, blood giving sets (e.g. Hypotension prophylaxis

but this was also found to contain a Baxter Ref RMC2071B) have a relat- for Caesarean section

ively large ﬁlter diameter of 200 l,

whereas solution administration sets We read with interest the obstetric

(e.g. Baxter Ref RMC9608), have anaesthesia practice survey (Burns et al.

smaller 15 l diameter ﬁlters. Second, Anaesthesia 2001; 56: 794–8) regarding

both companies have conﬁrmed that hypotension prevention and manage-

the risk of crystal formation is signiﬁ- ment for women undergoing spinal

cantly reduced in 10% solutions.

anaesthesia for elective Caesarean sec-

Within our own hospital, we have a tion. The authors appear to suggest that

Ôtransport rucksackÕ, to be used during the current literature Ôno longer advo-

interhospital transfers. It contained one catesÕ the use of ﬂuid preloading prior to

container of 20% Mannitol solution, the administration spinal anaesthesia.

which when checked was also found to Moreover, the authors cite our previous

Figure 9

302

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Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

Correspondence

volume before spinal anaesthesia for

cesarean delivery: A qualitative sys-

tematic review. Anesthesia and Analgesia

2001; 92: 997–1005.

study [1] and suggest that pulmonary We submit that two limited impressions

oedema is an important implication that may be responsible for this practice.

may result from large preload volumes. Firstly, while unopposed uterine vaso-

We agree that many studies indeed constriction has been observed in the

exist that demonstrate a lack of efﬁcacy early animal studies, human studies have

of individual modalities in preventing demonstrated advantageous effects of

spinal anaesthesia-induced hypotension, phenylephrine over ephedrine in terms

including ﬂuid preloading [2] However, of neonatal acid base status and cate-

the limitations of crystalloid preload cholamine plasma levels [7]. Second,

administration as a single agent directed the concern for signiﬁcant maternal

at the incidence of hypotension should bradycardia has been cited [8], which

not lead to abandonment of the practice. required rescue atropine in 11 ⁄ 19

3 Ngan Kee WD, Khaw KS, Lee BB,

Wong MMS, Ng FF. Metaraminol

infusion for maintenance of arterial

blood pressure during spinal anaesthesia

for cesarean delivery: The effect of a

crystalloid bolus. Anesthesia and

Analgesia 2001; 93: 703–8.

4 Tsen LC, Boosalis P, Segal S, Datta S,

Bader AM. Hemodynamic effects of

simultaneous dministration of intra-

venous ephedrine and spinal anaesthesia

for Cesarean delivery. Journal of Clinical

Anesthesia 2000; 12: 378–82.

Minimizing the severity of hypotension, patients with heart rate < 60.min⁾¹

.

reducing vasopressor requirements [3], However, in this study relatively large

and reducing red blood cell loss by median phenylephrine doses (600 lg)

haemodilution (prior to the usual blood were used. We recognise that further

loss associated with Caesarean delivery) clariﬁcation of the optimal vasopressor

are all meritorious effects. Moreover, the technique for hypotension prophylaxis

risk of pulmonary oedema with crystal- is needed, particularly in the setting of

loid volume prophylaxis in the setting of placental insufﬁciency. It is possible that

a healthy parturient undergoing elective a combination of ephedrine and phenyl-

Caesarean section appears theoretical ephrine, as observed in a recent study

and does not seem to be a problem using an infusion of both (ephedrine

5 Ngan Kee WD, Khaw KS, Lee BB, Lau

TK, Gin T. A dose–response study of

prophylactic intravenous ephedrine for

the prevention of hypotension during

spinal anaesthesia for caesarean delivery,

Anesthesia and Analgesia 2000; 90:

1390–5.

in clinical practice. Interestingly, the 2 mg + phenylephrine 10 lg.min⁾¹

)

6 Rolbin SH, Cole AFD, Hew EM,

Pollard A, Virgint S. Prophylactic

intramuscular ephedrine before epidural

anaesthesia for caesarean section: Effic-

acy and actions on the foetus and

newborn. Canadian Anaesthesia Society

Journal 1982; 29: 148–53.

decreases in colloid oncotic pressure may represent the most efﬁcacious so-

observed in the 20 and 30 ml.kg⁾¹lution [9]. We are currently examining

crystalloid preloading groups in our a similar combination (ephedrine 5 mg

study [1] were equivalent and no cases + phenylephrine 20 lg.ml⁾¹) in bolus

of pulmonary oedema occurred.

form to treat maternal hypotension in

In terms of vasopressor use, we agree this setting and believe it may be

that the efﬁcacy of ephedrine when used superior to either agent alone.

7 LaPorta RF, Arthur GR, Datta S.

Phenylephrine in treating maternal

hypotension due to spinal anaesthesia

for caesarean delivery: Effects on

neonatal catecholamine concentrations,

acid-base status and Apgar scores. Acta

Anaesthesiologica Scandinavica 1995; 39:

901–5.

prophylactically (by 62% of respondents)

We conclude that a single perfect

is variable [4] and likely to be dose antidote to the prevention and treatment

dependent [5] when administered as a of maternal hypotension may never be

bolus. However, a point that should be found. However, a multimodal ap-

emphasised is that the clinical studies to proach, including ﬂuid preloading and

date have been performed primarily on prophylactic vasopressor use, as partially

healthy term parturients undergoing demonstrated by Vercauteren et al. [10]

elective Caesarean deliveries. As such, may represent the optimal approach.

8 Thomas DG, Robson SC, Redfern N,

Hughes D, Boys RJ. Randomised trial

of bolus phenylephrine or ephedrine for

maintenance of arterial pressure during

spinal anaesthesia for caesarean section.

British Journal of Anaesthesia 1996; 76:

61–5.

although this survey did specify uncom-

Y. R. Loughrey

plicated pregnancies, the emerging trend

S. Datta

for titrating pressors to effect while

L. C. Tsen

abandoning a ﬂuid preload (12.9% re-

Harvard Medical School,

spondents) should not be enthusiastically

Boston, MA 02115, USA

encouraged; potentially detrimental ef-

E-mail: jloughrey@partners.org

fects may occur in the setting of placental

9 Mercier FJ, Riley ET, Frederickson

WL, et al. Phenylephrine added to

prophylactic ephedrine infusion during

spinal anaesthesia for elective cesarean

section. Anesthesiology 2001; 95:

668–74.

insufﬁciency. Prophylactic ephedrine at

large doses has been associated with

References

lower umbilical cord venous pH even 1 Park GE, Hauch MA, Curlin F, Datta

in healthy term pregnancies [6].

S, Bader AM. The effects of varying

volumes of crystalloid administration

before Cesarean delivery on maternal

haemodynamics and colloid osmotic

pressure. Anesthesia and Analgesia 1996;

76: 299–303.

We ﬁnd the survey results and com-

mentary concerning phenylephrine to

be interesting. These note that despite

having proven and comparable efﬁcacy

with ephedrine in treating maternal

10 Vercauteren MP, Coppejans HC,

Hoffmann VH, Mertens E, Adriaensen

A. Prevention of hypotension by a

single 5 mg dose of ephedrine during

small dose spinal anaesthesia in

hypotension, phenylephrine has not 2 Morgan PJ, Halpern SH, Tarshis J. The

been integrated into clinical practice.

effects of an increase of central blood

Ó 2002 Blackwell Science Ltd

303

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

prehydrated cesarean delivery patients.

Anesthesia and Analgesia 2000; 90:

324–7.

Aspirin and central neural

blockade

recently experienced an unusual difﬁ-

culty that has not been described to

date. A standard lumbar epidural was

performed for obstetric analgesia using

a Portex epidural pack. Identiﬁcation

of the epidural space was straightfor-

ward and catheter placement was easy.

Upon trying to slide the Tuohy needle

off the catheter, a severe resistance was

experienced and the only way of

removing the needle was to cut the

catheter at the distal end of the needle

with a sterile blade. The epidural ﬁlter

was then attached to this cut end and

the epidural analgesia was successfully

initiated.

The needle and remains of the

ÔjammedÕ catheter were sent to Portex

for further examination. Portex cut

through the plastic hub of the needle

to demonstrate the obstructed catheter

(see Fig. 10).

I, like many other anaesthetists, do

not use the feeding guide supplied

by the manufacturers with this pack.

Portex have suggested that the coiled

nature of the epidural catheter can lead

to coiling within the hub of the needle

if the feeding guide is not used.

Within our anaesthetic department of

13 consultants we recently discovered

that there was wide difference in opin-

ion regarding the safety of performing

spinal and epidural anaesthesia in pa-

tients taking aspirin. Subsequently, we

performed a postal survey of consultant

anaesthetists in the North-west region.

We were interested to see whether the

dose of aspirin was considered relevant

and whether anaesthetists had personally

been involved in the care of any patients

who had developed a spinal haematoma.

Responses were received from 239 of

the 430 questionnaires sent (56%).

More people felt an epidural carried

greater risk than a spinal. There was

considerably more caution with the

larger daily dose of aspirin; 2.1% of

respondents would not perform a spinal

on a patient taking 75 mg daily of

aspirin whereas 28% would not perform

an epidural on a patient taking 300 mg.

Several would perform these blocks if

the patient was taking aspirin alone but

not if they were also receiving other

anticoagulants. Five would perform a

bleeding time and would not perform a

block if this were prolonged. Many

commented that this was an issue of risk

vs. beneﬁt and the individual circum-

stances of each case would determine

the technique used.

A reply

We thank the authors for their excellent

letter, which very much represents our

own views. We agree that not all

current literature advocates abandon-

ment of ﬂuid loading prior to Caesarean

section under spinal anaesthesia but are

concerned by the trend for recent

publications to demonstrate no thera-

peutic beneﬁt. We believe that the

advantages of this therapy far outweigh

its largely theoretical hazards. We also

agree that a solution to the complex

problem of hypotension associated with

this procedure will require more so-

phisticated research techniques than

have hitherto been applied.

Presently, we are strongly of the

opinion that techniques excluding ﬂuid

loading are potentially harmful to both

mother and fetus.

R. G. Wilkes

S. M. Burns

C. M. Cowan

Liverpool Women’s Hospital,

Liverpool, UK

I have changed my practice as a result

of this experience and suggest that

others consider doing the same.

Epidural catheter

S. Sampathkumar

Broomﬁeld Hospital,

Chelmsford CM1 7HJ, UK

Many complications of epidural cath-

eter placement have been described. I

Of respondents, 23 (9.6%) had per-

sonally been involved in the care of a

patient who had developed a spinal

haematoma and, of these, ﬁve had not

received spinal or epidural anaesthesia.

Eight cases were fully anticoagulated

with warfarin or heparin, and in others,

coagulation failure was associated with a

variety of causes such as septicaemia,

renal failure and major transfusion.

Another respondent commented that

in 11 years as a neuroanaesthetist, he

had seen two patients suspected of

having spinal haematoma following

epidural blockade, neither had a haem-

atoma on investigation.

The American Society for Regional

Anesthesia (ASRA) issued a consensus

statement regarding antiplatelet drugs

and neuraxial block in 1998 [1]. ASRA

believe that the use of antiplatelet drugs

Figure 10

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.....................................................................................................................................................................................................................

Correspondence

alone does not create a level of risk that

will interfere with the performance of

neuraxial blocks. However, the con-

current use of other medications affect-

ing clotting mechanisms, such as oral

anticoagulants, standard or low mo-

lecular weight heparin, may increase

the risk of bleeding complications in

these patients.

The antithrombotic effect of aspirin is

seen at low doses (30–300 mg daily).

Doses above 30 mg daily result in

maximal platelet thromboxane inhibi-

tion within 3–5 days and increasing the

dose reduces the time to maximal

inhibition [2]. This was not reﬂected

in answers to our survey, where more

anaesthetists would be cautious if a

patient was taking aspirin 300 mg daily

and reﬂects poor understanding of the

patients receiving LMWH less than 3 h

following the insertion of the epidural

catheter; 5% of patients had the epidural

catheter removed within 10 h of the last

dose of LMWH, some within 1–2 h of

LMWH. Following the removal of the

epidural catheter, 15% of patients

received LMWH within 3 h. There

were no documented adverse outcomes

following the use of epidural analgesia

and LMWH in these patients.

LMWHs are fractionated heparin,

which, like standarised heparin, bind

to antithrombin III to exert its antico-

agulant effect through the inhibition of

Factor Xa and other clotting factors [3].

The peak effect occurs at 3–4 h follow-

ing subcutaneous administration and at

12 h the anti-Xa levels are 50%.

LMWHs are primarily cleared by the

kidneys and are not subject to a satura-

ble pathway like heparin [4]. LMWHs

provide accurate and reproducible anti-

coagulation, which does not require

References

1 Urmey WF, Rowlingson JC. Do anti-

platelet agents contribute to the devel-

opment of peri-operative spinal

haematoma? Regional Anesthesia and

Pain Medicine 1998; Supplement 2: 23.

2 Bochner F, Lloyd JV. Aspirin for

myocardial infarction. Clinical phar-

macokinetic considerations. Clinical

Pharmacokinetics 1995; 28: 433–8.

3 Awtry EH, Loscalzo J. Aspirin.

Circulation 2000; 101: 1206–18.

4 Sonksen JR, Kong KL, Holder R.

Magnitude and time course of impaired

primary haemostasis after stopping

chronic low and medium dose aspirin

in healthy volunteers. British Journal of

Anaesthesia 1999; 82: 360–5.

pharmacodynamics of aspirin. After a An audit of the use of low

single dose of aspirin, platelet regener- molecular weight heparin and

ation restores platelet cycloxygenase epidural anaesthesia

(COX) activity by approximately 10%

per day [3]. Normal haemostasis will Low molecular weight heparins (LMWHs) laboratory monitoring or dose adjust-

occur if 20% of platelets have normal are increasingly used as prophylaxis ment.

COX activity; hence withdrawal of against deep vein thrombosis and there

Vertebral canal haematomas may

aspirin for 48 h is sufﬁcient to return is evidence that they are as effective in occur spontaneously and the relative

primary haemostasis to near normal [4]. orthopaedic patients as standard heparin risk is estimated at one per million

Patients therefore do not require a [1]. The combination of anticoagulation population per year [5], many of

prolonged discontinuation of treatment and central nerve blockade has caused which had coagulation disorder at the

prior to surgery to restore adequate concern amongst anaesthetists due to time of development of the haema-

haemostasis.

the increased risk of vertebral canal toma. The risk of developing a ver-

The evidence suggests that aspirin haematoma. This has been fuelled by an tebral canal haematoma following a

and non-steroidal anti-inﬂammatory increase in vertebral haematomas in central nerve blockade in combination

drugs alone pose only a small increased North America from 1993 [2].

risk but that in combination with other

with LMWH prophylaxis is extremely

We conducted a retrospective audit rare, the estimate is 1 : 2 250 000 [6],

drugs affecting coagulation, there may of the use of epidural catheters in 79 using the European dosing regimen of

be more signiﬁcant risk. The majority patients receiving LMWH therapy who enoxaparin 20 mg or 40 mg once

of the anaesthetists we surveyed would underwent elective major joint replace- daily. The risk factors associated with

balance the small risk of haematoma ment and epidural analgesia during a the development of a vertebral canal

against the beneﬁts of regional anaes- predetermined 6-month period. We haematoma are: degree of coagulation

thesia for each patient although a recorded the times of administration disorder, technical difﬁculty and re-

proportion consider aspirin therapy to of low molecular weight heparin and peated attempts at insertion of needle

be an absolute contraindication to the times of insertion and removal of or catheter, and coagulation status at

regional blockade. A centralised re- the epidural catheter. Not all the insertion and removal of epidural

porting system for serious complica- patients on which the data was collec- catheter. Both the insertion and the

tions such as this may allow for greater ted received LMWH prophylaxis; 76% removal of the catheter are believed to

assessment of risk factors and allow for had enoxaparin 20 mg once daily (od), be the times when haematomas may

more rational and consistent decision 6% received enoxaparin 40 mg od, 1% form [7]. The experiences in USA

making.

received tinzaparin 1000 mg od and resulted in recommendations being

16% did not have any anticoagulant proposed and extended to European

S. A. Harding

A. M. Severn

therapy.

The insertion of the epidural catheter

practice [4, 6].

The recommendations [4] are:

J. Calvert

Royal Lancaster Inﬁrmary,

Lancaster LA1 4RP, UK

occurred more than 10 h following the 1 The recommended dose and

last dose of LMWH. The subsequent frequency of the LMWH should not

dosing of LMWH results in 3% of be exceeded.

Ó 2002 Blackwell Science Ltd

305

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

arin. New England Journal of Medicine

1998; 338: 1774–5.

2 Insertion of the needle and placement

of the catheter to be delayed until 10–

12 h following the last dose of LMWH.

3 Removal of the catheter should be

delayed for 10–12 h following last dose

of LMWH.

4 Subsequent doses of LMWH to be

delayed for 2 h following insertion or

removal of the needle ⁄ catheter.

Our audit identiﬁes a number of areas

of practice in our hospital that do not

adhere to the recommendations. The

epidural catheters were all inserted in

excess of the recommended time delay;

however, subsequent administration of

LMWH and manipulations of the epi-

dural catheter did not follow the recom-

mendations.

We do not feel that the practice in

our hospital differs signiﬁcantly from

other hospitals in this country. We

propose that the time that the prophy-

lactic anticoagulant therapy is adminis-

tered be standardised where clinically

possible to facilitate routine windows of

opportunity for safe insertion and

removal of epidural. Also the type of

anticoagulant therapy should be docu-

mented on the epidural observation

chart and clear guidelines given regard-

ing the care and removal of the epidural

catheter.

epidural needle. It is quite possible that

constant plunger pressure with saline

may also avert this problem.

3 Weitz IJ. Low molecular weight hepa-

rins: a review. The New England Journal

of Medicine 1997; 337: 688–98.

4 Horlocker T, Heit MD, John A. Low

molecular weight heparin: Biochemis-

try, peri-operative prophylaxis regi-

mens and guidelines for regional

anaesthetic management: a review.

Anesthesia and Analgesia 1997; 85:

874–85.

S. Cohen

R. Chokkra

F. Bokhari

Robert Wood Johnson Medical

School, New Brunswick,

NJ 08901–1977, USA

5 Holtas S, Heiling M, Lonntoft M.

Spontaneous spinal epidural haema-

toma: findings at MR imaging and

clinical correlation. Radiology 1996;

199: 409–13.

Transient neurological

manifestations after epidural

analgesia with ropivacaine

Different studies and case reports

ascribed transient neurological manifes-

tations (TNM) after neuraxial anaesthe-

sia, at least in part, to lidocaine,

bupivacaine, mepivacaine and recently

to ropivacaine [1–5]. In fact, nerve

conduction block could be the expres-

sion of a reversible toxic effect [5] and

TNM are a moderate expression of this

toxicity. During epidural anaesthesia,

the transmeningeal transfer of local

anaesthetics may result in elevated

intrathecal concentrations [1] that prob-

ably contribute to TNM.

We report here a case of TNM after

epidural ropivacaine. A 58-year-old,

ASA II, male patient, underwent a

radical prostatectomy under general

anaesthesia. The patient was in the

supine position peroperatively. The

patient’s medical history included

hypertension and tetracycline hypersen-

sitivity, general anaesthesia for colono-

scopy, a thumb fracture reduction, a

laparotomy for Meckel’s diverticulum, a

prostate biopsy, no alcohol intake, he

stopped smoking 3 years ago, and his

current medication was bisoprolol.

6 Tryba M, Wedel DJ. Central neu-

roaxial block and low molecular weight

heparin: lessons learned from different

dosage regimens in two continents. Acta

Anaesthesiologica Scandinavica 1997; 41:

100–3.

7 Vandermeulen EP, Van Aken H, Ver-

mylen J. Anticoagulants and spinal-

epidural anaesthesia. Anesthesia and

Analgesia 1994; 79: 1165–77.

A simple technique to reduce

the incidence of accidental

dural puncture

The risk of spinal haematoma is rare

and none of the patients in this audit

suffered any adverse outcome to our

knowledge. However, with a little

education the risk of such a catastrophic

complication could be minimised and

practice improved to reach the recom-

mended standards.

We would like to respond to recent

comments (Reynolds. Anaesthesia 2001:

56: 1129) on our epidural technique. In

our practice we apply loss of resistance

to air technique, which helps identify a

nick in the dura with a small leak of

CSF. On many occasions, only a few

drops of CSF and not a constant leak

G. A. Matthews

Great Ormond Street Hospital for Sick helped identify dural puncture, which

Children, London, UK

could have been missed with the use of

saline. Upon inserting the epidural

needle, we remove the stylet when the

needle is engaged in the interspinous

ligament or the ligamentum ﬂavum.

Very often, it is difﬁcult for our

residents to advance the epidural needle

with one hand and apply constant

K. Davies

Royal Devon and Exeter Hospital,

Exeter

Prior to general anaesthesia, we

inserted an epidural catheter through a

17 gauge Tuohy needle in the L3–L4

interspace for postoperative analgesia.

We carried out a single needle pass and

there was no difﬁculty in threading the

catheter. No pain, paraesthesia or bleed-

ing was elicited at any time. The

epidural space was identiﬁed using loss

of resistance to air.

References

1 Nurmohamed MT, Rosendaal FR,

Buller HR, et al. Low molecular weight pressure on the plunger with the other

heparin vs. standard heparin in general hand. Excessive pressure with one hand,

by a resident, had caused dural puncture

when the needle was pushed in too far.

2 Wysowski DK, Talarico L, Bacsanyi J, By reinserting the stylet with each

and orthopaedic surgery: a meta-ana-

lysis. Lancet 1992; 340: 152–6.

After a test dose of 3 ml lidocaine 1%

with epinephrine 1 : 200 000, which

was negative for intrathecal or intravas-

Bostein P. Spinal and epidural haema-

toma and low molecular weight hep-

advancement of the needle, we remove

tissues that may enter and occlude the

306

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Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

Correspondence

4 Hiller A, Rosenberg PH. Transient

neurological symptoms after spinal

anaesthesia with 4% mepivacaine and

0.5% bupivacaine. British Journal of

Anaesthesia 1997; 79: 301–5.

cular injection, a bolus of 7 ml ropiva-

caine 0.75% was injected through the

epidural catheter, resulting in a T10

level of analgesia.

One hour after the initial dose, we

started a continuous epidural infusion of

ropivacaine 0.2% (the pump speed was

5 ml.h⁾¹). Ten hours after starting the

pump, the patient complained of slight

pain, so proparacetamol 2 g was given

twice and the pump speed increased to

7 ml.h⁾¹. Epidural analgesia lasted for

72 h.

5 Puolaka R, Haasio J, Pitkanen MT,

¨

et al. Technical aspects and postopera-

tive sequelae of spinal and epidural

anaesthesia: A prospective study of

3230 orthopedic patients. Regional

Anesthesia and Pain Medicine 2000; 25:

488–97.

Twelve hours after discontinuing the

epidural ropivacaine, the patient des-

cribed a violent bilateral burning sensa-

tion and pain in the back and the thighs,

which spread quickly to the legs and

feet. The movement of the lower

extremities, the examiner’s hand pres-

sure on the limbs, and the orthostatic

position of the patient exacerbated this

pain. We did not ﬁnd any reﬂex or

motor abnormalities, or neurological

deﬁcit.

The patient was treated with two

doses of subcutaneous morphine

10 mg, and intravenous ketoprofen

100 mg. Symptoms started to diminish

progressively and disappeared 12 h later

without leaving any sequelae. On fol-

low-up 2 weeks later, the patient did

not mention any pain or neurological

problem.

Intrathecal air following spinal

anaesthesia

We report an unusual case of transient

neurological symptoms (TNS) follow-

ing spinal anaesthesia. A 49-year old,

healthy woman underwent ambulatory

surgery for varicose veins under spinal

anaesthesia using 2% mepivacaine. Two

hours after recovery from the regional

anaesthesia, she developed very painful

paraesthesia of the lower buttocks and

both thighs. Magnetic resonance ima-

ging (MRI) showed two intrathecal air

bubbles (Fig. 11). The patient was hos-

pitalised for 5 days and treated with pain

medication. She was discharged home

without sequelae.

The incidence of TNS following

spinal anaesthesia varies [1], and de-

pends on anaesthetic, surgical and pa-

tient factors. A history of a radicular

disease, a lithotomy position during

surgery and early ambulation of patients

have been identiﬁed as risk factors [2].

It is known that an accidental, sub-

arachnoid injection of air may cause

severe headache [3]. Also, air may

persist for a long time after an intra-

Figure 11 MRI (Siemens Vision, 1.5

Tesla) 30 h after spinal anaesthesia showed

two air bubbles (diameters 2–3 mm,

arrow) adjacent to the cauda equina.

B. Al-Nasser

were not associated with paraesthesia or

discomfort.

´

M. Negre

C. Hubert

Clinique du Parc Saint Lazare,

60000-Beauvais, France

E-mail:balnasse@aol.com

M. Hu¨bler

R. J. Litz

R. von Kummer

D. M. Albrecht

Carl-Gustav-Carus University

Hospital,

References

01307 Dresden, Germany

E-mail: matthias.huebler@

mailbox.tu-dresden.de

1 Markey JR, Naseer OB, Bird DJ, et al. thecal injection [4]. We presume that

Transient neurological symptoms after

epidural analgesia. Anesthesia and Anal-

gesia 2000; 90: 437–9.

some air was injected in our patient.

Also, negative subarachnoid pressure

caused by a deep inspiration may be a

2 Ganapathy SG, Sandhu HB, Stockall CA, possible mechanism [5]. Although the

Hurley D. Transient neurologic symptom air did not compress the cauda equina, 1 Pollock JE, Neal JM, Stephenson CA,

References

following intrathecal Ropivacine. Anes-

thesiology 2000; 93: 1537–9.

it may have caused an irritation of the

nerves or meninges. neurotoxic

effect of mepivacaine cannot be exclu-

ded, but neither can neural irritation

Wiley CE. Prospective study of the

incidence of transient radicular irrita-

tion in patients undergoing spinal

anaesthesia. Anesthesiology 1996; 84:

1361–7.

A

3 Salazar F, Bogdanovich A, Adalia R,

et al. Transient neurologic symptoms

after spinal anaesthesia using isobaric 2% caused by the air; synergism of both

mepivacaine and isobaric 2% lidocaine. mechanisms is possible. Direct needle 2 Freedman JM, Li DK, Drasner K,

Acta Anaesthesiologica Scandinavica 2001; trauma appears unlikely in our patient

Jaskela MC, Larsen B, Wi S. Transient

neurologic symptoms after spinal

45: 240–5.

since the puncture and the injection

Ó 2002 Blackwell Science Ltd

307

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

anaesthesia: an epidemiologic study of

1863 patients. Anesthesiology 1998; 89:

633–41.

In spite of traditional departmental

guidelines still prevailing, many anaes-

thetists would be happy to accept

shorter fasting times for their patients.

The minimum fasting times quoted by

the highest number of anaesthetists

were 2 h for clear ﬂuids (113 anaesthet-

ists, range 0.5–6 h), 4 h for fruit juice

(73 anaesthetists, range 1–6 h), 4 h as

well for ﬁzzy drinks (74 anaesthetists,

range 1–8 h), 6 h for milk (99

respondents, range 2–8 h) and 6 h for

solid food (140 respondents, range

3–8 h).

Complications with shorter fasting

times were reported in 11 cases, ran-

ging from vomiting, reﬂux, and regur-

gitation to aspiration. Whether these

problems were due to shorter fasting

times, or would have happened in any

case, is not known. The risk of acid

aspiration resulting in aspiration pneu-

monia and possibly death of a patient

has led to the development of fasting

guidelines, in an attempt to allow time

for stomach emptying as a means to

reduce this risk. This is counterbalanced

by the reduction in patient comfort,

which is a consequence of prolonged

fasting, and it is a problem especially for

children and elderly patients, as well as

patients undergoing anaesthesia on a

warm day, as during prolonged fasting,

patients do experience hunger and

severe thirst [1].

Reference

1 Sutherland AD, Stock JG, Davies JM.

Effects of pre-operative fasting on

morbidity and gastric contents in

patients undergoing day – stay surgery.

British Journal of Anaesthesia 1986; 58:

876–8.

3 Aida S, Taga K, Yamakura T, Endoh

H, Shimoji K. Headache after attemp-

ted epidural block: the role of intra-

thecal air. Anesthesiology 1998; 88:

76–81.

4 Tedeschi E, Marano I, Savarese F, et al.

Neurological deficit following spinal

anaesthesia: MRI and CT evidence of

spinal cord gas embolism. Neuroradiology

1999; 41: 275–8.

Recording the conﬁrmation

of nasogastric tube placement

We would like to congratulate Dr

White (White. Anaesthesia 2001; 56:

1123) on his ingenious method of using

a capnograph to conﬁrm the correct

position of a nasogastric (NG) tube. We

recently conducted an audit in our

intensive care unit (ICU) and would

like to take this opportunity to remind

your readers of a simple but apparently

neglected method.

In a series of 21 NG tubes in our

ICU, we found 13 (62%) were inserted

in theatre prior to admission to the

ICU, of which 10 (48%) were inserted

before or during surgical procedures,

allowing the operating surgeon to

manually conﬁrm the position of NG

tubes intra-operatively. Simple manual

palpation enabled us to conﬁrm the

position of nearly 50% of NG tubes in

our series, and 77% of NG tubes in the

13 postoperative patients. However, the

weakness in our procedure is that

although the NG tubes are frequently

felt and their positions conﬁrmed ⁄

altered by the surgeon, this is rarely

recorded. We suspect this is also the

case in other hospitals.

5 Avellanal M, Olmedilla L, Ojea R,

Rueda ML, Navia J. Pneumocephalus

after spinal anaesthesia. Anesthesiology

1996; 85: 423–5.

Pre-operative ﬂuid fasting

for adult elective surgery

Optimal fasting times for adult patients

undergoing elective surgery have been a

much-discussed problem in the recent

past. We conducted a national survey to

enquire about current departmental

fasting guidelines. Questionnaires were

sent to the 283 Royal College tutors,

and 167 anaesthetists (60%) replied.

Not all respondents answered all

questions.

Guidelines are in place in 151

departments (90.4%). The majority of

them, 93 departments, follow traditional

rules of Ôfasting from midnight for mor-

ning listsÕ and fasting from early morn-

ing for an afternoon list. However, ﬂuid

intake until 4, 3, and 2 h prior to surgery

was acceptable in 40, 31, and 71 depart-

ments, respectively, already under cur-

rent guidelines. Day Case Anaesthesia as

well as anaesthesia for ECT ⁄ cardiover-

sion follow the same guidelines in 149

(89%) and 131 (79%) departments,

whereas the corresponding answers for

obstetric and MRI anaesthesia were 90

(54%) and 85 (51%).

This survey shows clearly that atti-

tudes have already changed away from

traditional fasting guidelines towards

shorter fasting intervals. Putting new

treatment concepts into practice usually

does take longer, but a move in this

direction is well under way.

We would therefore like to highlight

the message that it is both helpful to the

ICU staff and important in the man-

agement of postoperative patients that

intra-operative conﬁrmation of NG

tube position is documented.

Acknowledgements

We are grateful for the support from

the Royal College of Anaesthetists and

their provision of College Tutor

Addresses.

We are indebted to all College

Tutors who participated in the survey.

C. Y. Li

M. F. Mayall

As far as emergency operations are

concerned, 96 respondents (61%) indi-

cated that they would follow the rule

of Ôfasting for 6 h following food, and

4 h following a drinkÕ. In 15 depart-

ments, it was acceptable for patients

to have a drink until 2 h prior to the

anaesthetic, and 26 respondents replied

that individual decisions would be

made.

Kent & Canterbury Hospital,

Canterbury CT1 3NG, UK

R. Hebballi

P. J. Desai

S. Ju¨rgens

University Hospital of North Tees,

Stockton TS19 8PE, UK

A new angle on a Tuohy needle

We would like to report a manufactur-

ing defect in a Tuohy needle that

308

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Anaesthesia, 2002, 57, pages 284–313

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Correspondence

A possible cause of corneal

abrasions

reinforces the need to inspect all equip- prior to use, identiﬁcation of the

ment prior to use. epidural space would have been difﬁ-

An Abbott 18G Tuohy ⁄ 27G Whit- cult, and inability to withdraw the

acre combined spinal epidural kit stylet would have necessitated a second

(Abbot Critical Care Systems, Sligo, skin puncture.

I wish to report a possible aetiology for

the development of corneal abrasions,

which I feel may have been over-

looked in the literature. The main

identiﬁed causes of corneal abrasion in

non-ophthalmological anaesthesia is

trauma from facemasks, laryngoscopes,

and other airway devices but the

majority of non-ophthalmological an-

aesthetic cases of iatrogenic corneal

abrasions do not have a distinguishable

aetiology [1].

This was not the case in a lady who

recently underwent an emergency Cae-

sarean section for failure to progress.

The patient had used Entonox via a

demand ⁄ reducing valve during labour.

Whilst spinal anaesthesia was being

established, she was given a Hudson

mask with 50% oxygen and 50% nitrous

oxide at 10 l.min^-1. Once the block was

established, the nitrous oxide was

removed from the mixture and the

fresh gas ﬂow reduced to 4 l.min⁾¹

until the birth of her child. The Hudson

mask was used for a total time of

45 min. The patient denied that the

Hudson mask entered her eyes at any

point during the procedure.

Republic of Ireland) was selected for

The importance of checking equip-

regional anaesthesia for elective lower ment before use is well recognised and

segment Caesarean section. Prior to this should also include the Tuohy

performing combined spinal-epidural needle and ease at which the stylet can

anaesthesia, the Tuohy needle was be removed. We have reported this

noted to be misaligned in the hori- defect to the manufacturer as a quality

zontal plane at the junction of the hub control matter.

and the shaft at an angle of approxi-

D. A. Wright

mately 10° (Fig. 12). Furthermore, the

M. W. M. Rucklidge

stylet could not be withdrawn from

King Edward Memorial Hospital,

the Tuohy needle suggesting the Tu-

Perth, Australia

ohy needle assembly had been dam-

aged during the ﬁnal packaging

process.

Several defects of Tuohy needles 1 Millman AM. Faulty epidural needle.

have previously been reported inclu-

Anaesthesia 1994; 49: 270.

ding separation of the hub from the 2 Schlake PT, Peleman RR, Winnie AP.

References

needle [1, 2] and protrusion of the

stylet beyond the tip of the Tuohy

needle [3]. Misalignment between the

Separation of the hub from the shaft of

a disposable epidural needle. Anaesthes-

iology 1999; 68: 611–13.

hub and shaft of Tuohy needles has 3 Stevens J. Faulty Tuohy needle.

also been reported [4], however, not to

Anaesthesia 1999; 54: 1120.

the degree we have observed or with 4 LeDez K, Kneeling P. ÔMalignmentÕ of

an associated ﬁxed stylet. Had the

defect in this case not been recognised

epidural needles. Anaesthesia 1984; 39:

1255–7.

The next day the patient developed

severe blepharospasm. The ophthalmo-

logical opinion was that the drying

effect of the gas had caused bilateral

central corneal abrasions, for which they

could not offer any published evidence.

She made a full recovery with residual

corneal scars below the visual axis that

do not affect her vision, suggesting that

the original cause was drying of the

interpalpebral area of the eyes [2].

Despite extensive Medline searches

and correspondence with the Drug and

Therapeutics agencies, it appears this

form of exposure keratopathy had not

been reported as an adverse event in

awake patients. It may be that we

should change our practice to use a

mouthpiece and a demand ⁄ reducing

valve rather than a facemask to deliver

Entonox whilst establishing spinal an-

aesthesia.

H. Pollock

Southampton University Hospital,

Southampton SO16 6YD, UK

Figure 12

Ó 2002 Blackwell Science Ltd

309

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

References

Reference

1 Gild WM, Posner KL, Caplan RA,

Chleney FW. Eye injuries associated

with anesthesia. A close claims analysis.

Anaesthesiology 1992; 76: 204–8.

2 Bready LL. Complications in Anesthesia.

Edited by John L. Atlee MD. Phil-

adelphia, W.B. Saunder, 1999: 777–81.

1 Domino KB, Posner KL, Caplan RA,

et al. Airway injury during anaesthesia: a

closed claims analysis. Anesthesiology

1999; 91: 1703–11.

A reply

Thank you for allowing us to comment

on Dr Dickinson’s letter. The incident

described is of great concern to Tyco

Healthcare and we have conducted a

through investigation. Each step of the

manufacturing and packaging process

for the Yankauer Suction Instrument

was analysed, the potential problem

identiﬁed, and appropriate corrective

action implemented. The photograph

provided of the affected product shows

a gross defect which would be clearly

visible to the clinician prior to use.

Further, it is likely that this defect

would prevent the product from func-

tioning properly, once again alerting

the user.

To put this incident in perspective,

during the past year customers around

the world have used over 17 million

Tyco Yankauer Suction instruments. A

review of our complaint history on

this product has shown this to be the

only reported defect of this type. We

sincerely regret the fact that one of our

customers received a damaged product.

However, we ﬁrmly believe that the

corrective action we have taken will

prevent recurrence of this incident.

Further, our data indicate this is an

isolated incident.

A faulty Yankauer suction

catheter

We would like to bring to your atten-

tion a problem with a Kendall Argyle

Yankauer suction catheter (Tyco Ltd),

which potentially could have been a

hazard to patients.

Whilst restocking the anaesthetic

room between cases, a vigilant anaes-

thetic assistant noticed the faulty suction

catheter (Figs 13 and 14) and removed

it before use. The catheter was still in its

intact sterile packaging. There was no

evidence of the missing part of the tip in

the packaging. In anaesthetic practice it

is common to use Yankauer suction

catheters under direct vision using a

laryngoscope. However, these catheters

are frequently used blindly in a resusci-

tation setting.

Figure 14

Airway injury during general anaes-

thesia is a signiﬁcant source of morbid-

ity for patients and a source of liability

for anaesthetists. Perforation of the

pharynx or oesophagus is a serious,

life-threatening injury [1]. Approxi-

mately 6% of claims in the American

Society of Anesthesiologists (ASA)

Closed Claims database were for airway

injury. Of these, injuries to the pharynx

(19%) and oesophagus (18%) were

amongst the most common [1].

This incident was reported to the

Medical Devices Agency and the man-

ufacturers (Tyco Ltd) were contacted.

Tyco Ltd informs us that they produce

approximately 8 million Yankauer suc-

tion catheters per annum. They have

reviewed the manufacturing process and

have identiﬁed the source of the prob-

lem, which is thought to be related to the

packaging process. This is the ﬁrst time a

problem of this nature has occurred.

However, the company is implementing

changes in their quality control and is

purchasing new packaging equipment to

ensure this does not happen again.

Wherever the setting, had this par-

ticular catheter been used blindly, con-

siderable damage to the patient’s soft

palate could have occurred.

A. M. Morley

Tyco Healthcare UK,

Gosport PO13 OAS, UK

The signiﬁcance of post mortem

tryptase levels in supporting

a diagnosis of anaphylaxis

After reading the case report regarding a

lady who suffered a fatal anaphylactic

reaction at induction (Konarzewski &

De’Ath. Anaesthesia 2001; 56: 497–8)

and reply (Girgis. Anaesthesia 2001; 56:

1016–17), we feel neither author

emphasised the signiﬁcance of such a

vastly elevated serum tryptase level

M. C. Dickinson

Royal London Hospital,

London, E1 1BB, UK

A. Klein

Homerton University Hospital,

London, UK

E-mail: mcdickinson@doctors.org.uk addition, we would like to reiterate

(185 lg.l⁾¹

,

normal < 1 lg.l⁾¹). In

Figure 13

310

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Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

Correspondence

that the absence of cutaneous and autopsy evidence to dispute the diagnosis 3 comparison (of data with accepted

respiratory features of anaphylaxis does of anaphylaxis, we believe this lady died values) and, importantly,

not preclude the diagnosis.

as a result of an anaphylactic reaction.

4 change – improving performance,

doing something positive.

For many the Ôaudit trailÕ can be a

rocky path. Whilst publication of survey

data has value, this is but one step along

the way to successful audit.

Following death, body tissues under-

go autolysis and therefore tryptase

enzyme leaks from tissue mast cells. This

results in elevated serum tryptase levels if

blood samples are taken post mortem.

This was shown by Randall et al. [1],

and Edston and Van Hage-Hamsten [2].

The former found that 31 out of 49

autopsy cases had raised tryptase levels

when there was no evidence of anaphy-

laxis. However, of the 31 cases, 24 had

values of only 1–5 lg.l⁾¹, two had

values of 5–10 lg.l⁾¹, ﬁve had val-

ues of > 10 lg.l⁾¹and one had a value

of 106 lg.l⁾¹The ﬁgure of 185 lg.l⁾¹is

far in excess of any of Randall’s 31

autopsy cases. Edston and van Hage-

Hamsten [2] looked at 193 post mortem

patients of known, unexplained and

anaphylactic deaths. They found they

required a signiﬁcantly high cut-off

tryptase value of 10 lg.l⁾¹to provide a

speciﬁcity for anaphylaxis of 88%. This

was increased to 93% if a cut-off of

20 lg.l⁾¹was used.

M. G. Way

C. L. Baxendine

Southampton General Hospital,

Southampton SO16 6YD, UK

A. Badrakumar

P. Jefferson

References

1 Randall B, Butts J, Halsey JF. Elevated

postmortem tryptase in the absence of

anaphylaxis. Journal of Forensic Sciences

1995; 40: 208–11.

D. R. Ball

Dumfries and Galloway

Royal Inﬁrmary,

Dumfries DG1 4AP, UK

2 Edston E, van Hage-Hamsten M.

Beta-tryptase measurements post-

mortem in anaphylactic deaths and in

controls. Forensic Science International

1998; 93: 135–42.

References

1 Secretaries of State for Health, England,

Wales, Northern Ireland and Scotland.

Working for patients Cmd 555.

London: HMSO, 1989.

3 Ian SD, Roberts R, Pumphrey SH.

The autopsy in fatal anaphylaxis. In:

Lowe DG, Underwood JCE, eds.

Recent Advances in Histopathology 19

London: Churchill Livingstone,

2000:145–62.

2 What is Audit? In: Irvine D, Irvine S,

eds. Making Sense of Audit. Oxford:

Radcliffe Medical Press, 1991: 16–22.

Radial artery cannulation –

a simple positioning aid

Audit of audit …

We feel the main reasons for raised

The ideal arm position for inserting a

radial artery cannula is full supination of

the forearm with the wrist fully dorsi-

ﬂexed. An anaesthetist’s assistant is usu-

ally press-ganged into holding the arm

and wrist in position, with varying

degrees of success. Also, increasingly

commonly these days, the anaesthetist

may be working single-handed and the

ODP may well be busy concentrating

on other vital duties. To make this

procedure a Ôone-manÕ job, the simple

solution is a 500-ml bag of normal

saline. When the bag is hooked onto

the patient’s index ﬁnger and allowed to

hang over the edge of the bed (Figs 15

and 16), a near perfect position is

achieved entirely without assistance.

Try it – you’ll like it!

post mortem serum tryptase levels are: In their letter ÔAn audit of audit and

autolysis, trauma resulting in organ continued educational and professional

damage (one case had a reported tryp- developmentÕ (White & Osmer. Anaes-

tase level of 170 lg.l⁾¹following a car thesia 2001; 56: 1003–4) the authors use

accident [2]) and anaphylaxis ⁄ anaphy- the term audit inappropriately. What

lactoid reactions. Autolysis is likely to they in fact describe are the results from

give low to moderate tryptase levels, i.e. a postal survey of 58 UK Anaesthetic

1–10 lg.l⁾¹[1], whereas trauma and Departments on their audit and related

anaphylaxis give much higher ﬁgures, activities. Their letter is essentially a

i.e. > 20 lg.l⁾¹[2].

description and discussion of a survey.

Recent Advances in Histopathology This is data collection, which is just one

[3] advise that post mortem tryptase part of ÔauditÕ.

levels should be interpreted with

Audit gained much greater medical

caution unless grossly elevated and and political prominence in the UK with

supported by a suggestive clinical his- the publication of the Department of

tory. The absence of cutaneous and Health white paper Working for patients in

respiratory manifestations of anaphylaxis 1989 [1]. Since then, audit has come to

suggests a rapid onset, for example an mean many things to many people, and

intravenous allergen as opposed to an therein lies confusion. Whilst deﬁnitions

ingested allergen. Out of a series of 56 of audit vary [2], the principles and

iatrogenic anaphylactic deaths, none characteristics as applied to the medical

demonstrated cutaneous manifestations, or clinical setting remain essentially the

and only 13 demonstrated upper airway same. Be it part of a process, trail or cycle,

M. B. Coates

Derriford Hospital,

Plymouth, UK

oedema and bronchial obstruction [3].

audit consists of four steps. These are:

As we have a good case report history 1 categorisation (deﬁning valid criteria

Blocked emergency syringe

(also presented to Konarzewski and for audit),

De’Ath’s anaesthetic department),

Following a number of letters that have

2 collection (of relevant performance appeared concerning the value, or other-

a

tryptase level of 185 lg.l⁾¹, and no data),

wise, of ÔbespokeÕ preﬁlled emergency

Ó 2002 Blackwell Science Ltd

311

Correspondence Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

bolus and from the Emergency Drug career in anaesthesia. If a sibling (the

Box was taken an unopened box con- proband) has conﬁrmed MH, i.e. has

taining a preﬁlled syringe of epinephrine been screened by muscle biopsy then

(Martindale Pharmaceuticals). The box your colleague has a 50% chance of

was opened, the cap removed [1], and being affected. Assuming the proband

the syringe was applied to one of the has been tested in the UK, your

Kimal Clave valves that had been used colleague will have been offered diag-

with great success on the Intensive Care nostic screening as part of the family

Unit. However, it was found that the follow up. Should this show he ⁄ she is

plunger could not be depressed. Subse- also susceptible to MH this will not

quently the syringe was attached to a inﬂuence his ⁄ her career choice with

standard Ôthree-wayÕ tap. Sadly, again the regard to the practice of anaesthesia. We

plunger could not be depressed, and so do not advise MH susceptible patients

the syringe was replaced with another, to alter their life style, although the

which worked correctly.

Armed Services do have certain restric-

Once the incident was over, I found tions. We have several MH susceptible

the syringe in question and it appeared patients who work in the operating

to have a blocked nozzle, which no theatre environment, one of whom was

amount of manual pressure was able to an ENT surgeon who spent most of his

dislodge. There was no subsequent working life in non-scavenged theatres

problem with the Clave valves reported, using Boyle-Davis gags.

although at the time we did not

In the laboratory there is an obvious

Figure 15

suspect that there would be, so it was dose ⁄ response effect of halothane on

not speciﬁcally looked for. The syringe MH muscle tissue. It is reasonable to

was sent back to the manufactures for suppose this occurs in the clinical situ-

their analysis. In their reply they sug- ation although it is by no means the

gested that the end was blocked with a only explanation of the varying severity

piece of plastic that Ômay be part of a of a malignant hyperthermia crisis.

Kimal Clave valve.Õ Subsequent discus-

P. J. Halsall

sion revealed that the syringe was

St James’s University Hospital,

known to be incompatible with the

Leeds LS9 7TF, UK

Clave device.

I feet it is important not to over

dramatise what occurred. No more than

a few seconds could have been ÔlostÕ as a

result of the failure described above, and

so it is doubtful that this signiﬁcantly

common, and many now appear in this

affected the patient. That said, I think it is

important to highlight this incompatibil-

2001, 16 surveys have been published in

ity between preﬁlled syringes from Mar-

e-Surveys

Surveys on anaesthetic practice are

journal. For this year to November

Anaesthesia. The numbers of contacts

range from 29 to 735. All except one are

to anaesthetic departments or societies

and rely on postal questionnaires, usu-

ally with a stamped reply envelope to

encourage response. Such paper-based

tindale and the Kimal Clave valve system.

D. J. Aldington

Portsmouth Hospital,

Portsmouth, UK

Reference

1 Menon, R. An unusual case of tracheal

surveys present a formidable logistical

challenge with signiﬁcant administrative

Figure 16

tube obstruction. Anaesthesia 2001; 56:

700–1.

commitment and high postage costs.

Replies must then be collated, usually

requiring some form of data entry into a

syringes (Webster et al. Anaesthesia 2001;

56: 818–20, Rayen & Rasanayagam.

Anaesthesia 2001; 56: 711–12, Wikner

computerised format. This is invariably

labourious and error prone. We propose

a better way to survey.

& Tighe. Anaesthesia 2001; 56: 712), I Malignant hyperpyrexia and a

would like to draw attention to one career in Anaesthesia

deﬁnite failing of employing them.

Our proposal relies on the participa-

tion of a recognised and respected

anaesthetic network established nation-

ally and represented at hospital level.

During a cardiac arrest on an Inten- I read the letter (Tillyard. Anaesthesia

sive Care Unit, a situation arose in 2001; 56: 1020) concerning advising a

which an item as ÔsimpleÕ as a syringe, colleague with a family history of

failed. A patient required an epinephrine malignant hyperthermia (MH) about a

312

Ó 2002 Blackwell Science Ltd

Anaesthesia, 2002, 57, pages 284–313

.....................................................................................................................................................................................................................

Correspondence

Such networks already exist, in the form the ﬂexible wire. In our hands there is manufacturer shall remain nameless)

of College Tutors and Association still a struggle to pass the dilator because are fully computerised with compre-

Linkmen. We seek either College or the skin has not been cut properly. hensive monitoring of vital signs,

Association endorsement to use their Rather than removing the metal needle anaesthetic agent and gas concentrations

networks to participate in national sur- after Seldinger wire passage, we now and respiratory parameters. Rotameters

veys of anaesthetic activity. A network make the skin cut onto the shaft of the are electronically represented. These

would be linked by electronic mail needle before it is withdrawn. This machines are obviously Ôstate of the

using a dedicated distribution list. This gives a ﬁrm support to cut onto, a single artÕ and, no doubt, very expensive. It

would require some form of national clean measured skin incision can be amuses me that, following a number of

co-ordination, but the outlay in terms made, and risk of knife damage to the power cuts and Ôsoftware malfunctionsÕ,

of manpower and money would be Seldinger wire can be avoided.

relatively modest, probably the present

P. Nalwaya

it has become common practice to

make sure that there is an Ambubag or

similar within easy reach on the back of

the machine. All in the name of

progress!

cost of one paper survey. Once imple-

W. F. S. Sellers

mented, electronic surveys could then

Kettering General Hospital,

be rapidly and cheaply conducted, with

Kettering, Northants NN16 8UZ,

all participants gaining beneﬁt from

UK

R. Langford

Royal Hampshire County Hospital,

Winchester SO22 5DG, UK

shared information. Comparative data

on practice can readily be used for local,

regional or national audit. Planning,

preparation and participation are crucial

for such a collaborative venture.

Whilst a survey reliant on unsolicited

Another use for the

laryngoscope

Nitrous oxide

As recently described (Holtham

&

Weaver. Anaesthesia 2001; 56: 1121),

we all feel difﬁculty when introducing

laryngeal mask airways, whether the

regular or the disposable types. The

Ôreverse to frontÕ method is ﬁne and so

are numerous other methods, but the

potential for causing minor or major

trauma remains in all methods used. In

my opinion and experience, the old

laryngoscope should be made use of

when difﬁculty is experienced in place-

ment of a laryngeal mask. One does not

have to do ÔfullÕ laryngoscopy but use

the blade and light to move away the

tongue to make that little extra space.

This will invariably succeed in almost all

cases. The laryngoscope blade here is

used only as a sort of tongue depressor!

I hope this will be found useful and

feedback will be welcome to help assess

this method.

Carter, in his reply to my letter on this

topic (Carter. Anaesthesia 2002; 57: 82)

writes that Ôthe really exciting use of

nitrous oxide is in motor racing where

injecting nitrous oxide, either into the

fuel line or the air intake, enhances

performanceÕ. Sadly, I think Carter has

missed the point. What would be really

exciting would be to inject nitrous

oxide into the surgeon’s fuel line or

air intake. Would there still be an

enhanced performance? If so, nitrous

oxide would become the greatest thing

since sliced bread!

E-mail has been recently published [1]

the response was low (20%), prompting

editorial comment [2]. All exchanged

information would necessarily have to

complywiththeDataProtectionAct,but

thisconsiderationshouldnotbeseenasan

impediment to the plan. We christen

such a proposal Ôe-SurveysÕ, ÔeÕ for elec-

tronic, economic, efﬁcient and easy.

D. R. Ball

P. Jefferson

Dumfries and Galloway Royal

Inﬁrmary,

Dumfries DG1 4AP, UK

J. S. M. Zorab

Bristol, UK

References

1 Soliman HM, Me´lot C, Vincent J-L.

Sedative and analgesic practice in the

intensive care unit: the results of a

European survey. British Journal of

Anaesthesia 2001; 87: 186–92.

2 Park GR. Sedation and analgesia –

which way is best? British Journal of

Anaesthesia 2001; 87: 183–85.

H. S. Bhogal

Alexandra Hospital,

Redditch B98 7UB, UK

All in the name of progress

Better skin incision for

Seldinger dilator insertion

As a relatively new Senior House

Ofﬁcer in anaesthesia, I feel most pri-

vileged to be using new fully compu-

terised anaesthetic machines in our

operating theatres. These units (the

Skin incision for the venous line dilator

is usually made along the Seldinger wire

with the knife blade facing away from

Ó 2002 Blackwell Science Ltd

313

Article Doi

DOI: 10.1111/j.1365-2044.2002.2520_39.x

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