Full text of DOI:10.1007/BF03024868

974
REPORTS OF INVESTIGATION
Inadequate preanesthesia
equipment checks in a
simulator
Allysan Armstrong-Brown B MED (Hons) FANZCA,
J Hugh Devitt MD MSc FRCPC,
Matt Kurrek MD,
Marsha Cohen MD FRCPC*
Purpose: To assess how completely anesthesiologists check their machinery and equipment before use, and to
determine what influence seniority, age and type of practice may have on checking practices.
Methods: One hundred and twenty anesthesiologists were videotaped during a simulated anesthesia session.
Each participant was scored by an assessor according to the number of items checked prior to the induction of
anesthesia. A checklist of 20 items derived from well-publicized, international standards was used.
Results: Participants were grouped according to their type of practice. Overall, mean scores were low. The ideal
score was 20. There were no differences among university anesthesiologists (mean score 10.1, standard devia-
tion 4.3), community anesthesiologists (7.5 ± 4.3) and anesthesia residents (9.0 ± 3.8). Each of these groups
scored, on average, better than medical students (3.6 ± 3.7) (P < 0.05). Neither age (r = 0.15, P > 0.1) nor
number of years in practice (r = -0.18, P > 0.1) correlated with score.
Conclusions: Our study suggests that the equipment-checking practices of anesthesiologists require considerable
improvement when compared with national and international standards. Possible reasons for this are discussed
and some remedial suggestions are made.
Objectif : Évaluer le degré de vérification des appareils faite par les anesthésiologistes avant de les utiliser et
déterminer l’influence de l’ancienneté, de l’âge et du type de pratique sur les habitudes de vérification.
Méthode : Cent vingt anesthésiologistes ont été filmés sur vidéocassette pendant une session d’anesthésie
simulée. Chaque participant a été coté par un évaluateur selon le nombre d’éléments vérifiés avant l’induction de
l’anesthésie. On a utilisé une liste de 20 éléments dérivée de normes internationales bien connues.
Résultats : Les participants ont été regroupés selon leur type de pratique. Globalement, les scores moyens ont
été faibles. Le meilleur score a été de 20. Il n’y avait pas de différence entre les anesthésiologistes spécialistes
(moyenne de 10,1 et écart type de 4,3), les anesthésiologistes omnipraticiens (7,5 ± 4,3) et les résidents en
anesthésie (9,0 ± 3,8). Chacun de ces groupes a affiché des scores moyens meilleurs que ceux des étudiants de
médecine (3,6 ± 3,7) (P < 0,05). Il n’y avait pas de corrélation entre l’âge (r = 0,15,P > 0,1) ou le nombre
d’années d’exercice (r = -0,18, P > 0,1) et le score obtenu.
Conclusion : Notre étude permet de présumer que les habitudes de vérification de l’équipement des anesthé-
siologistes, comparées aux normes nationales et internationales, doivent être de beaucoup améliorées. Les cau-
ses possibles de cette situation sont examinées et certaines solutions sont proposées.
From the Department of Anaesthesia, Sunnybrook and Women’s College Health Sciences Centre, and Centre for Research in Women’s
Health and the Department of Health Administration,* University of Toronto.
Address correspondence to: Dr. Matt Kurrek, Department of Anaesthesia, Sunnybrook and Women’s College Health Sciences Centre,
2075 Bayview Avenue, Room M3-200, Toronto, Ontario, M4N 3M5 Canada.
Presented at the annual meeting of the Canadian Anesthesiologists’ Society, in Calgary, June, 1999. Supported with a grant from the
Physicians of Ontario through the Physicians Services Incorporated Foundation. Dr Cohen is the recipient of a Senior Scientist Award
from the Medical Research Council of Canada.
Accepted for publication June 15, 2000.
CAN J ANESTH 2000 / 47: 10 / pp 974–979

Armstrong-Brown et al.: ANESTHESIA MACHINE CHECKS
975
AILURE to check equipment and equip-
ment failure have been repeatedly identified
in published critical incident reviews as
to them, as part of the testing procedure. All participants
received a 30 min familiarization with the mannequin,
gas machine, physiological monitor and simulation facil-
ity. All participants were given the same clinical scenario
and patient information. A research assistant (respiratory
therapist) played the role of the circulating nurse, and
was available to answer questions and provide assistance
and information with respect to the equipment during
the familiarization and the simulation session.
Participants were given a standardized patient in
the simulator environment. All were told that the case
they were about to manage was the first case of the
day for that operating room. They were instructed to
manage the patient and to start the case as was their
customary practice, but subjects were not prompted
to check the anesthesia machine for faults. The per-
formance of each participant was videotaped for later
review and assessment. All videotapes were analyzed
by a single reviewer.
F
important, preventable contributors to anes-
thesia-related morbidity and mortality.1–4
In response to this, several national anesthesia orga-
nizations have published guidelines and checklists to
improve knowledge of, and compliance with, pre-use
anesthesia equipment checking practices.5–7 The
Canadian Anesthesiologists’ Society requires that “a
pre-anesthetic (equipment) checklist shall be complet-
ed prior to the initiation of anesthesia”, and provides
members with such a checklist annually.8
Despite such efforts, checking practices appear to
remain poor.9–11 The goal of this study was to exam-
ine how anesthesiologists check their equipment. We
hypothesized that the completeness of the inspection
would vary with the seniority, age and/or type of
practice of the anesthesiologist.
We constructed a checklist of 20 items (Figure 1),
being an amalgamation and modification of several
widely available checklists.5–7 Our checklist was not
designed as a comprehensive list of all items which
should be checked at the beginning of each day, or at
the beginning of any case. Items were included only if
Methods
After institutional research ethics board approval, writ-
ten, informed consent was obtained from all partici-
pants. Four groups were identified according to type of
practice: anesthesiologists in university practice (UA),
anesthesiologists in community practice (CA), residents
in anesthesia programs (Res), and medical students in
their anesthesia rotation (MS). Medical students were
in their final year and participated in the study during
the second week of a two-week anesthesia clerkship.
Residents were in their final six months of training and
eligible to sit the national specialty examination.
University and community anesthesiologists were
drawn from multiple institutions from across Ontario.
All subjects participated in a study involving a clinical
scenario in an anesthesia simulator, in which the partici-
pant assumed the role of the anesthesiologist.
Our Simulation Centre consists of a mock operating
room containing an anesthesia gas machine (Ohmeda,
Excel 210 SE), patient physiological monitors (Datex,
AS3), anesthesia drug cart, operating table, instrument
table, and electrocautery machine. Drapes, intravenous
infusions and surgical instruments were used to enhance
the realism of the simulation. The patient mannequin
(MedSim Advanced Medical Simulations Ltd) was posi-
tioned on the operating table, and the role of the mem-
bers of the operating room team, such as the surgeon
and circulating nurse, were scripted and acted by the
investigators. The details of our simulation centre have
been described elsewhere.1 2 All subjects were asked to
participate in a study that evaluated the simulator as a
testing tool and subjects were aware that simulated
patient and/or technical problems would be presented
Checked Omitted
1. High pressure system
a. O cylinder: contents
b. pi2pelines: connections
2. Low pressure system
a. control valves/flow meters
b. vaporizers
____
____
____
____
____
____
____
____
____
____
c. precircuit leaks: check
d. breathing system
i. assembly
____
____
____
____
____
____
____
____
____
____
____
____
ii. leaks
iii. unidirectional valves
iv. APL valve function
e. O failure device
f. O2flush
3. Ventil2ator
a. function
b. leaks
c. low pressure alarm
4. Scavenging system
a. connections
____
____
____
____
____
____
____
____
____
____
b. suction on
5. Emergency ventilation system
a. functional
____
____
6. Other apparatus
a. airway equipment
b. suction: i. configuration
ii. adequate function
____
____
____
____
____
____
FIGURE 1 Checklist for preanesthesia equipment check

976
CANADIAN JOURNAL OF ANESTHESIA
TABLE Demographic characteristics of groups
Group
N
Age(years)* Years in Practice†
University anesthesiologists
27 39.5 7.1 8.0 6.5
Community anesthesiologists 41 44.6 8.9 14.2 9.9
Residents
Medical students
21 31.5 3.7 NA
31 26.6 3.0 NA
Values are expressed as mean SD
*Age differences significant between all groups (Bonferroni
P < 0.05) except Res vs MS (P = NS)
†No. of years in practice significantly different for UA vs CA
(P < 0.05).
their performance or omission could be reliably dis-
cerned on the videotape.
Each item was classified as “checked” or “omitted”.
For reliability and simplicity, if the participant
attempted to check an item (even if it was performed
incompletely or ineffectively), the item was classified
as having been checked.
Each participant was given a score out of twenty
according to the number of items attempted. Only
items performed prior to the “induction” of anesthe-
sia were counted.
FIGURE 2 Number of participants checking each item on the
checklist.
For statistical analysis, group differences were com-
pared using analysis of variance, with P < 0.05 consid-
ered significant. Subjects’ age and years in practice
were compared using the Pearson correlation coeffi-
cient, using the square root transformation of the per-
formance score for the machine check (to normalize
distribution), and with P < 0.05 and r > 0.8 consid-
ered significant. Comparison of mean age and number
of years in practice for all groups was made using one-
way analysis of variance followed by pair-wise compar-
isons (t test with Bonferroni correction).
transformation of the score, there was no correlation
between the two (Figure 5).
Discussion
We used a simulated anesthesia environment, and
found that performance of preanesthesia equipment
inspection was poor regardless of the age or experi-
ence of the anesthesiologist. The performance of some
participants may have reflected their discomfort at
being outside their normal environment, in a “test”
situation. Most participants agreed at the end of their
session in the simulator, however, that the simulation
was realistic.1 3 Only a small proportion of participants
performed no checks at all, suggesting that most par-
ticipants realized that an equipment check was
required prior to this “first case of the day”. We did
not attempt to “weight” the criteria, although we rec-
ognize that the accurate checking of some criteria in
our checklist may be more important to patient safety
than others. Not all participants were familiar with the
anesthetic machine and monitors before their simula-
tor session. Extensive orientation was therefore given
prior to the session, in order to minimize the potential
bias this may have introduced to our study.
Results
The demographic characteristics of each group are sum-
marized in Table. Differences in ages were statistically
significant for all groups, except between MS and Res.
CA had significantly more years in practice than UA.
The numbers of participants checking each individ-
ual item are displayed in Figure 2.
The group differences were not significant, except
that MS scored on average lower than either UA, CA
or Res (Figure 3).
We then compared the scores with the age of each
participant (Figure 4). There was no correlation, either
positive or negative, between the square root transfor-
mation of the score, and increasing age. Similarly, when
the number of years in practice (for UA and CA partic-
ipants) was analyzed with respect to the square root

Armstrong-Brown et al.: ANESTHESIA MACHINE CHECKS
977
FIGURE 5 Individual score vs number of years in practice. UA,
university anesthesiologists; CA, community anesthesiologists. No
correlation found between score and number of years in practice (r
= -0.18, P = 0.14).
FIGURE 3 Mean scores (+SD) for each group. UA, university
anesthesiologists; CA, community anesthesiologists; Res, anesthe-
sia residents; MS, medical students. *MS mean score significantly
lower than UA, CA and Res (P < 0.05).
reflect the habitual checking practices of many anes-
thesiologists.
This raises the question of why pre-use checking
practices may be inadequate. It has been suggested
that thorough checking takes too long,1 4 although
this may be operator- and experience-dependent.
Time taken for equipment checking may be perceived
by some as reducing the time available for surgery, and
these anesthesiologists may believe there is a trade-off
between patient safety and increased time efficiency in
the operating room. Some anesthesiologists may dele-
gate checking of equipment to others,9 although ulti-
mate (and legal) responsibility for the proper
functioning of the equipment is currently deemed to
be with the anesthesiologist.9,15
Knowledge of the structure, physics and function
of the anesthetic machine is integral in the training of
specialist anesthetists. Lack of knowledge of the
equipment should therefore not be an impediment to
adequate pre-use checking practices. In a study
designed to look at the ability of the FDA checklist to
improve equipment fault detection by anesthesiolo-
gists, March and Crowley1 6 used a multiple-choice
questionnaire (MCQ) about machine function to
compare the ability of participants to detect machine
faults with their theoretical knowledge of equipment.
Overall fault detection rates were low, and although
there was a statistically positive correlation with MCQ
score, the authors commented that the correlation was
not as strong as they had expected. They suggested
that in their study, “practitioners may understand the
function of the machines but may be unable to apply
that understanding to practical clinical skill”.
FIGURE 4 Individual score vs age. UA, university anesthesiolo-
gists; CA, community anesthesiologists; Res, anesthesia residents;
MS, medical students. No correlation found between age and
score (r = 0.15, p = 0.1).
Most participants entered the simulator session
with the expectation that something was going to go
wrong. (This is in contrast to the inherent safety and
relative predictability of day-to-day anesthesia prac-
tice.) This expectation should have motivated partici-
pants to be even more thorough than they might
usually be in checking the equipment in the simulator.
We feel, therefore, that it is likely that our results

978
Olympio et al.1 1 demonstrated that even when res-
idents attempt to check their equipment, the check is
frequently incorrectly or incompletely performed,
which further limits their ability to identify machine
faults. In our study, we did not assess the effectiveness
of checking procedures; we do not know if the partic-
ipants understood what they were doing, or how
effective were the checks they performed.
CANADIAN JOURNAL OF ANESTHESIA
There have been criticisms of these checklists
because of perceived incompleteness or ineffective-
ness,2 0 and because of time constraints as discussed
above. Some effort has been made to produce abridged
versions of the checklists,2 1but it is unclear whether this
produces unacceptable reductions in the ability to iden-
tify equipment faults.
2 2
Berge et al
.
have used an anesthesia simulator in a
novel approach to training personnel in the detection of
machine faults. Their simulator uses an anesthetic
machine which is normal in external appearance but
which is internally modified such that multiple machine
dysfunctions may be reproduced. This has the potential
to improve the understanding of the machine by trainees,
by mimicking faults which may be infrequent but impor-
tant in clinical practice. Such technology is expensive and
not widely available, however, limiting its usefulness.
Our study indicates that the performance of resi-
dents is as poor as the performance of consultants, sug-
gesting that experience alone is unlikely to improve
checking practices. Current teaching places little
emphasis on this vital part of anesthesia practice. There
may be a role for compulsory inclusion of refresher
courses in pre-use checking procedures in continuing
medical education.
To improve compliance with checking procedures,
measures may be taken at an institutional or national
level to require anesthesiologists to document what
checks they have performed at the start of each case.
If pre-use checks are truly a patient safety issue, it is no
longer sufficient to make these checks an optional part
of an anesthetic. Failure to check represents a rule-
based error in anesthesia, which should be reducible.2 3
There is widespread acknowledgment in the field of
anesthesia that pre-use equipment checking proce-
dures are important in patient safety. Although there
are no randomized, controlled trials published to
prove that efficient checking procedures reduce the
frequency of incidents or accidents in anesthesia, “fail-
ure to perform an adequate check” is repeatedly iden-
tified as the primary error in one-quarter to one-third
of all critical incidents.1–3
It is possible that, with continued improvements in
monitoring over the last 15-20 yr, anesthesiologists
have come to rely on a combination of vigilance and
monitoring to warn them when there is something
wrong with their equipment. In the Australian Incident
Monitoring Study of 2000 critical incidents, about 75%
of equipment failures were, or could have been, identi-
fied by a combination of standard monitors and anes-
thetic vigilance.1 7 To rely on monitors in this way is to
reduce the margin of patient safety, as monitors often
indicate problems only after considerable harm or phys-
iological disturbance has occurred. In the confusion
which can surround a critical incident, it should be reas-
suring to the anesthesiologist that the equipment was
checked and in working order at the start of the case.
This of course does not preclude the possibility of unex-
pected equipment failure, emphasizing the need for
effective emergency response and crisis management.4
Given the results of this and previous studies, how
can the performance of preanesthesia checks be
improved? As detailed above, recommendations from
national professional bodies and warnings from critical
incident reviews have not been sufficient.
Olympio et al.1 1 attempted to improve the perfor-
mance of resident anesthetists by intensive training ses-
sions, involving videotaping of residents’ performances,
followed by review with faculty and then repeat exami-
nation of checkout procedures several weeks later.
Subjects who received the extra training and review ses-
sions scored higher than controls on repeat testing, but
there was no long-term follow-up and it is unclear
whether differences would have been sustained.
Checklists and visual aids have been formulated
with the aim of making it easier for anesthesiologists
to perform pre-use checks rapidly and completely.5–7,18
Use of these is not widespread in clinical practice.
There is some debate as to whether their use improves
performance when compared with an anesthesiolo-
gist’s usual checkout methods.15,19 Groves et al.1 4
found that the use of the visual aid produced by
Adams1 8 (based on the checklist of the Association of
Anaesthetists of Great Britain and Ireland) resulted in
overall improvement in fault detection, although some
of their prearranged machine faults were discovered
less often when the aid was used.
It is not uncommon to find major faults in equip-
ment in routine use. Barthram and McClymont,2 4
using the Association of Anaesthetists of Great Britain
and Ireland’s checklist for anesthetic machines, found
faults in 60% of machines checked. 18% of these were
deemed to be serious, i.e. having the potential to lead
to rapid disaster.
In other areas of human endeavour, where the
results of an error may be catastrophic (the analogous
nature of aviation is often cited), formal equipment
checking procedures are frequently instituted.

Armstrong-Brown et al.: ANESTHESIA MACHINE CHECKS
979
7 Australian and New Zealand College of Anaesthetists.
Anesthesia is such an area, but there is, as yet, no com-
pulsion on the part of the anesthesiologist to check
that all equipment is in working order.
Protocol for checking the anaesthetic machine.
Melbourne: Australian and New Zealand College of
Anaesthetists, 1997.
In summary, the type of practice, age or number of
years in practice of the anesthesiologist has no effect
on the completeness of the pre-use anesthesia equip-
ment check; a consultant was as likely to check his or
her equipment as well as the residents they teach.
Lack of correlation between score and number of
years in practice suggests that familiarity does not breed
complacency with regard to checking equipment.
Rather, our study suggests that anesthesiologists check
their equipment inadequately from early in their careers
and do not tend to improve with experience. We sug-
gest that our professional organizations need to review
their current policies on equipment checks, and attempt
to improve education as the first step in improving
patient safety in this area.
8 Canadian Anesthesiologists’ Society. CAS Guidelines to
the practice of anesthesia. Toronto: Canadian
Anesthesiologists’ Society, 1998.
9 Mayor AH, Eaton, JM. Anaesthetic machine checking
practices. A survey. Anaesthesia 1992; 47: 866–8.
10 Clayton DG, Barker L, Runciman WB. Evaluation of
safety procedures in anaesthesia and intensive care.
Anaesth Intensive Care 1993; 21: 670–2.
11 Olympio MA, Goldstein MM, Mathes DD. Instructional
review improves performance of anesthesia apparatus
checkout procedures. Anesth Analg 1996; 83: 618–22.
12 Kurrek MM, Devitt JH. The cost for construction and
operation of a simulation centre. Can J Anaesth 1997;
44: 1191–5.
13 Devitt JH, Kurrek M, Cohen M. Participants’ evaluation
of a simulator based evaluation. Anesthesiology 1999;
91: A1131.
14 Groves J, Edwards N, Carr B. The use of a visual aid to
check anaesthetic machines. Is performance improved?
Anaesthesia 1994; 49: 122–5.
15 Cundy J, Baldock GJ. Safety check procedures to elimi-
nate faults in anaesthetic machines. Anaesthesia 1982;
37: 161–9.
16 March MG, Crowley JJ. An evaluation of anesthesiolo-
gists’ present checkout methods and the validity of the
FDA checklist. Anesthesiology 1991; 75: 724–9.
17 Webb RK, van der Walt JH, Runciman WB, et al.
Which monitor? An analysis of 2000 incident reports.
Anaesth Intensive Care 1993; 21: 529–42.
Addendum
Updated versions of anesthesia equipment checking
standards may be found at:
www.asahq.org/ProfInfo/FDA.html
www.aagbi.org/docs/checklist.doc
www.cas.ca/public/
Acknowledgments
We would like to acknowledge the assistance of Melissa
Shaw RRT and Chris Lewczuk in data collection, and
Dr. Jean-Paul Szalai and Jenny Lam-McCulloch in sta-
tistical analysis.
18 Adams AP, Morgan M. Checking anaesthetic machines
– checklists or visual aids? (Editorial) Anaesthesia 1993;
48: 183–6.
19 Manley R, Cuddeford JD. An assessment of the effec-
tiveness of the revised FDA checklist. AANA Journal
1996; 64: 277–82.
20 Jackson IJB, Wilson RJT. Association of Anaesthetist’s
checklist for anaesthetic machines. Problem with detec-
tion of significant leaks. Anaesthesia 1993; 48: 152–3.
21 Berge JA, Gramstad L, Grimnes S. An evaluation of a
time-saving anaesthetic machine checkout procedure.
Eur J Anaesthesiol 1994; 11: 493–8.
22 Berge JA, Gramstad L, Jensen Ø. A training simulator
for detecting equipment failure in the anaesthetic
machine. Eur J Anaesthesiol 1993; 10: 19–24.
23 Runciman WB, Sellen A, Webb RK et al. Errors, inci-
dents and accidents in anaesthetic practice. Anaesth
Intensive Care 1993; 21: 506–19.
References
1 Cooper JB, Newbower RS, Kitz RJ. An analysis of major
errors and equipment failures in anesthesia manage-
ment: considerations for prevention and detection.
Anesthesiology 1984; 60: 34–42.
2 Craig J, Wilson ME. A survey of anaesthetic misadven-
tures. Anaesthesia 1981; 36: 933–6.
3 Heath ML. Accidents associated with equipment.
Anaesthesia 1984; 39: 57–60.
4 Webb RK, Russell WJ, Klepper I, Runciman WB.
Equipment failure: an analysis of 2000 incident
reports. Anaesth Intensive Care 1993; 21: 673–7.
5 United States Food and Drug Administration.
Anesthesia apparatus checkout recommendations,
1993. Rockville, MD: Federal Register, February 1987.
6 Association of Anaesthetists of Great Britain and Ireland.
Checklist for anaesthetic apparatus. A recommended
procedure based on the use of an oxygen analyser.
London: Association of Anaesthetists of Great Britain
and Ireland, 1990.
24 Barthram C, McClymont W. The use of a checklist for
anaesthetic machines. Anaesthesia 1992; 47: 1066–9.