Full text of DOI:10.1007/BF03020944

REPORTS OF INVESTIGATION
315
Airway complications in
infants: comparison of
laryngeal mask airway
and the facemask-oral
airway
Miriam Harnett MB FFARCSI,
Brian Kinirons MB FFARCSI,
Anne Heffernan MB FFARCSI,
Catherine Motherway MB FFARCSI,
William Casey MB FFARCSI
Purpose: To compare the incidence of airway complications in children less than one year of age whose airways
were maintained during anesthesia with either a laryngeal mask airway (LMA) or a facemask and oral airway
(
FM-OA).
Methods: We randomized 49 - ASA class 1&2 - infants to an LMA or FM-OA group. All infants were undergoing
minor general, urological or orthopedic procedures. Anesthesia was induced and maintained with halothane in
nitrous oxide 50% and oxygen. The airway was removed in both groups when the infant was awake. The occur-
rence of airway complications (breath-holding, coughing, laryngospasm, secretions, obstruction and oxygen satu-
ration < 95%) at induction of anesthesia, intraoperatively and during emergence from anesthesia was recorded.
Results: Airway complications occurred perioperaively in 15 of 27 infants in the LMA group and in 5 of 22 infants
in the FM-OA group (P :0.02).
Conclusion: In infants, the use of the LMA is associated with an increased incidence of airway complications
compared with the use of the FM-OA.
Objectif : Comparer l’incidence de complications de la canulation chez des enfants de moins d’un an dont l’ac-
cès aux voies aériennes a été maintenu pendant l’anesthésie, soit avec un masque laryngé (ML), soit avec un
masque et une canule orale (M-CO).
Méthode : Nous avons réparti 49 enfants - ASA I et II - en groupes ML ou M-CO. Tous les enfants devaient
subir une intervention mineure, urologique ou orthopédique. L’anesthésie a été induite et maintenue avec de
l’halothane dans un mélange à 50 % de protoxyde d’azote et d’oxygène. La canule a été retirée chez tous les
enfants à leur réveil. On a noté l’occurrence de complications de la canulation (arrêt de la respiration, toux, laryn-
gospasme, sécrétions, obstruction et saturation en oxygène < 95%) lors de l’induction de l’anesthésie, pendant
l’opération et pendant la récupération de l’anesthésie.
Résultats : Les complications peropératoires de la canulation sont survenues chez 15 des 27 enfants du groupe
ML et chez 5 des 22 enfants du groupe M-CO (P : 0,02).
Conclusion : Chez les enfants, l’usage du ML, comparé à celui d’un masque et d’une canule orale, est associé
à une incidence accrue de complications de la canulation.
From the Department of Anaesthesia, Our Lady’s Hospital for Sick Children, Crumlin, Dublin 12, Ireland.
Address correspondence to: Dr. Miriam Harnett, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s
Hospital, Boston, MA 02115, U.S.A. Phone: 617-732-8218; Fax: 617-732-6798; E-mail: mharnett@bics.bwh.harvard.edu
Accepted for publication January 8, 2000.
CAN J ANESTH 2000 / 47: 4 / pp 315–318

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CANADIAN JOURNAL OF ANESTHESIA
N children undergoing general anesthesia, air-
way patency can be maintained by tracheal
intubation, by facemask with or without an oral
airway or by the laryngeal mask airway (LMA).
one of two groups. Group 1 (n = 27) - LMA group -
had an appropriately sized LMA inserted. The LMA is
now available for use in children in 4 sizes 1,1.5, 2 and
2.5. However during the period of the study only sizes
1 & 2 were available for use in children under one year
of age. A size #1 LMA was used in children <6.5 kg
and a size #2 in children > 6.5 kg. Children in group
2 (n = 22) had their airway maintained using the
appropriate sized Guedel airway and facemask.
I
The large occiput of an infant makes it difficult to
maintain the head in reasonable alignment in the
extended position, and the large tongue in relation to
the size of the oral cavity makes the infant more prone
to airway obstruction. This, coupled with the fact that
children have a higher oxygen consumption, means
that the pediatric population is more prone to develop
intraoperative and postoperative hypoxia.
Thus, many anesthesiologists routinely intubate the
tracheas of all children under the age of one year. The
complications associated with intubation in this age
group include - increased airway resistance during
spontaneous respiration, a higher incidence of laryn-
gospasm, endobronchial intubation and post extuba-
tion glottic edema.
All infants were anesthetized by one of three anes-
thetic registrars, all of whom were experienced in air-
way management with the LMA and the facemask and
oral airway in infants prior to the commencement of
the study. The infants were unpremedicated.
Anesthesia was induced with halothane 4% in nitrous
oxide 50% and oxygen, with the patients breathing
spontaneously through a Mapleson E circuit. The
electrocardiograph and arterial saturation (Nellcor
180) were monitored continuously from induction of
anesthesia. Intravenous access was established after
induction. Anesthesia was judged sufficient for inser-
tion of the LMA or Guedel airway by jaw relaxation
plus evidence of plane 3 of stage 3 surgical anesthesia
as judged by absence of lid reflex, eye position (immo-
bile eyes with semi-dilated pupils) and ventilation pat-
tern (diaphragmatic pattern of breathing). In group 1
the LMA was inserted in the conventional manner as
described by Brain and in group 2 (FM-OA) the
Guedel airway was inserted in the usual way. The cuff
of the LMA was inflated according to the manufactur-
er’s guidelines. Correct placement of the LMA was
determined as follows: resistance to continued
advancement of the LMA with forward bulging of the
larynx during insertion and outward movement of the
LMA with cuff inflation. Airway patency with either
the LMA or Guedel airway was confirmed by observ-
ing synchronous respiratory movements of the chest
and anesthetic reservoir bag, by lack of indrawing of
intercostal and supraclavicular spaces and by confirma-
tion on auscultation of air entry in both axille by gen-
tly inflating the reservoir bag. The LMA was secured
to the maxilla.
The LMA is widely used for ensuring airway paten-
cy in the pediatric population. Several studies have
assessed the use of the LMA in children but few have
focused on its use in infants in the first year of life. It
is in this group that the relative anatomy of the upper
airway differs most from that of the adult population.
Thus, difficulties with insertion and positioning of the
LMA might be expected to occur more frequently in
this age group. Mizushmia et al. inserted a size #1
LMA in 50 infants # 10 kg. They achieved a clinically
clear airway in 94% at the first attempt: second or third
attempts were required in the other three cases.
However, despite securing a patent airway in all
patients initially, 12 patients (24%) subsequently
1
developed delayed airway obstruction.
We examined the difference in oxygen saturation
and the incidence of airway complications such as
laryngospasm, coughing, breathholding and obstruc-
tion during anesthesia using either a conventional
facemask-oral airway (FM-OA) or an LMA in infants
up to one year of age undergoing anesthesia for minor
general, urological and orthopedic procedures.
Methods
Rectal acetaminophen or diclofenac was adminis-
tered to all children and a regional block was pre-
formed where appropriate. All patients breathed
spontaneously. Anesthesia was maintained with
nitrous oxide 50% in oxygen with halothane 1-3% as
required. At the end of the procedure, the volatile
agent was switched off in the usual manner and oxy-
gen 100% was administered for one minute prior to
transfer to the post anesthetic care unit (PACU). In
the PACU oxygen 40% was administered via a T-piece
(LMA group) or clear plastic mask (FM-OA group)
Following institutional ethical committee approval
and informed parental consent, 49 children, ASA I-II,
aged from birth to one year post gestational age were
recruited. Exclusion criteria included pre-term infants,
infants with a history of near miss sudden infant death
syndrome or apneic attacks, infants with signs of an
upper respiratory tract infection during the previous
week or infants with any airway malformation.
Standard contraindications to the use of a LMA were
also respected. Patients were randomly allocated to

Harnett et al.: AIRWAY COMPLICATIONS
317
and either the LMA or the Guedel airway was
removed when the infant was awake. Monitoring of
oxygen saturation continued up to the time that rou-
tine post anesthetic room criteria were met.
obstruction) laryngospasm occurred in one infant in
the LMA group. Severe hypoxemia (SpO 44%) devel-
2
oped with bradycardia. The LMA was removed, oxy-
gen 100%, atropine and succinylcholine were
administered and anesthesia proceeded uneventfully.
The occurrence of upper airway complications (i.e.
breath-holding, coughing, laryngospasm, secretions,
obstruction and oxygen saturation < 95%) in the peri-
operative period was recorded by the registrar who
had anesthetized the infant. Airway obstruction was
defined as respiratory in-drawing with lack of syn-
chronous movement of the chest and anesthetic reser-
voir bag. Data were analyzed using Student’s t test
and Chi- squared test. A P value of < 0.05 was con-
sidered statistically significant.
Discussion
There was an increase in the incidence of airway com-
plications in the LMA group. Fifteen of twenty-seven
infants in the LMA group compared with five of twen-
ty-two in the FM-OA group had airway complications
(P : 0.02). Intraoperative airway obstruction occurred
only in the LMA group. This is the first study which
has compared the difference in airway complications
in infants having their airways maintained with either
a LMA or a facemask and oral airway.
Results
Forty-nine children were included in the study, 27 in
the LMA group and 22 in the FM-OA group. There
were no differences between the two groups with
regard to age, weight and ASA status (Table I).
Likewise the operative procedures were similar in both
groups.
At the time of insertion of airway two complications
occurred - breath-holding in one infant and airway
obstruction in another - both were in the LMA group.
Nine airway complications occurred intraoperatively -
six in the LMA group and three in the FM-OA group.
The airway became obstructed in three infants - all in
the LMA group. During emergence from anesthesia
nine airway complications occurred - seven in the LMA
group and two in the FM-OA group (Table II).
No infant required tracheal intubation. In one
McGinn, in his retrospective analysis of the use of
the LMA in the pediatric population, found no differ-
ence in the incidence of correct placement when either
the McNicol rotational or Brain technique was
employed as the technique of choice for insertion.
However, he did note that difficulty with LMA inser-
tion was more frequent in children less than one year
of age, as were other problems during induction of
2
anesthesia more common in this age group.
A considerable amount of work has been reported
with regard to the best time to remove the LMA.
McGinn reported problems in 2 of 76 (2.6%) in whom
the LMA was removed before return of airway reflexes,
compared with 14 of 129 (10.9%) in whom the LMA
2
was removed after return of airway reflexes. Mason
reported airway complications in 26 of 200 children
when the LMA was removed awake. He recommended
the use of an antisialogue to reduce the accumulation of
infant in group 1, the SpO decreased to 91% two
2
minutes after insertion of a size #2 LMA. Despite
3
increasing the FiO to 100% there was no improve-
secretions within the mask aperture. Laffon suggested
2
ment in saturation. The LMA was removed and
that there were fewer complications if the LMA is
removed during anesthesia. However, both Kitching
4
replaced by a size #1 LMA, the SpO immediately
2
increased to 98%. Grade 4 (> 10 sec with complete
and Samarkandi suggest that there is no difference in
the incidence of complications whether the LMA is
5,6
removed awake or anesthetized, while Parry on the
other hand recommends that the LMA should be left in
situ until it is expelled spontaneously by the awake
TABLE I Demographic data
Group 1 ( LMA )
Group 2 ( FM-OA )
7
child.
Age (mo)
Weight (kg)
ASA status I/II
6.90 ± 2.8
8.12 ± 2.4
20/7
6.02 ± 2.6
7.94 ± 2.5
18/4
The use of the LMA in pediatric anesthesia is increas-
ing. However, there is little published work on the use
8
of the size #1 LMA. Those that have used it have
urged caution with its use. The anatomical differences
between infants and children suggest that a satisfactory
position is more difficult to achieve in infants. It also
appears that the LMA is not widely used when anes-
thetizing children under 1 year of age.
The LMA was developed following cadaveric stud-
ies in adults. The sizes available for pediatric use are
TABLE II Incidence of airway complications
Group 1 (LMA) Group 2 (LMA)
P
3
n = 27
15
n = 22
Airway Complications
Perioperatively
5
0.02

318
CANADIAN JOURNAL OF ANESTHESIA
scaled down versions of the adult sizes. The differ-
ences in airway anatomy between children, particular-
ly infants, and adults suggest that the LMA may not
be as successful in infants less than one year of age.
The infant has a relatively large tongue, the glottis lies
higher and more anteriorly than in the adult, while the
vocal cords are angled more forwards and downwards.
The epiglottis is large and floppy and may lie against
the posterior pharyngeal wall which may cause airway
obstruction. One difference between the adult and
pediatric use of the LMA is the incidence of malposi-
tion as diagnosed by fibreoscopy - Rowbottom report-
anaesthesia. Paediatr Anaesth 1993; 3: 23–8.
3 Mason DG, Bingham RM. The laryngeal mask airway
in children. Anaesthesia 1990; 45: 760–3.
4 Laffon M, Plaud B, Dubousset AM, Ben Haj’hmida R,
Ecoffey C. Removal of laryngeal mask airway: airway
complications in children, anaesthetized versus awake.
Paediatr Anaesth 1994; 4: 35–7.
5 Kitching AJ, Walpole AR, Blogg CE. Removal of the
laryngeal mask airway in children: anaesthetized com-
pared with awake. Br J Anaesth 1996; 76: 874–6.
6 Samarkandi AH. Awake removal of the laryngeal mask
airway is safe in paediatric patients. Can J Anaesth
1998; 45: 150–2.
9
ed partial airway obstruction in 19% of children
which is twice the incidence reported by Payne in the
7 Parry M, Glaisyer HR, Bailey PM. Removal of LMA in
children (Letter). Br J Anaesth 1997; 78: 337–8.
8 Wilson IG. The laryngeal mask airway in paediatric
practice (Editorial). Br J Anaesth 1993; 70: 124–5.
9 Rowbottoom SJ, Simpson DL, Grubb D. The laryngeal
mask airway in children. A fibreoptic assessment of
positioning. Anaesthesia 1991; 46: 489–91.
10 Payne J. The use of the fibreoptic laryngoscope to con-
firm the position of the laryngeal mask (Letter).
Anaesthesia 1989; 44: 865.
1
0
adult population. Lopez-Gil reported a higher com-
plication rate with use of the size #1 LMA and com-
mented that this may be related to the smaller margin
1
1
of error for accurate placement.
An important finding in our study is the incidence
of intraoperative airway obstruction. This occurred
only in infants in the LMA group. This tendency for
LMA displacement has previously been reported and
Mason has emphasized the necessity for secure fixa-
3
tion of the LMA in infants. In Mizushima’s series of
11 Lopez-Gil M, Brimacombe J, Alvarez M. Safety and effi-
cacy of the laryngeal mask airway. A prospective survey
of 1400 children. Anaesthesia 1996; 51: 969–72.
5
0 infants, although a clear airway was secured initial-
ly, complete or partial airway obstruction developed
subsequently in 12 /50 (24%) of cases. These authors
urge continuous vigilance for airway obstruction
1
when using the LMA in infants.
In this study we used halothane for induction and
maintenance of anesthesia. We acknowledge that the
use of sevoflurane is increasing and that with its use
the overall incidence of airway complications may be
reduced. However, halothane is still used extensively
worldwide. In our study one of the most notable find-
ings was that of intraoperative airway obstruction in
the LMA group and it is unlikely that the use of
sevoflurane would have influenced this complication.
In conclusion, the results of this study show a dif-
ference in the incidence of airway complications
between two groups of infants who had their airways
maintained either with a facemask and Guedel airway
or a LMA during anesthesia. The implications of this
study suggest that the LMA should be used with cau-
tion in children less than one year of age and the anes-
thesiologist should be aware of the potential for
intraoperative airway obstruction.
References
1
Mizushima A, Wardall GJ, Simpson DL. The laryngeal
mask airway in infants. Anaesthesia 1992; 47: 849–51.
McGinn G, Haynes SR, Morton NS. An evaluation of
the laryngeal mask airway during routine paediatric
2