Case Report
Brunei Int Med J. 2012; 8 (4): 205-209
Laryngeal mask airway (LMA-ProSeal) malfunction causing acute airway obstruction Binu Puthur SIMON and Syed Harun HABIBULLAH Department of Anaesthesiology, RIPAS Hospital, Brunei Darussalam
ABSTRACT The Laryngeal Mask Airway ProSealTM (LMA-ProSealTM; Laryngeal Mask Company Limited) is a reusable supraglottic airway device developed to enhance supraglottic airway protection and extend the benefits of the classic LMA (Laryngeal Mask Airway) to greater number of patients. Added features include an additional drain tube to channel fluid away from the airway and a tighter seal against the glottic opening with no increase in mucosal pressure. Clinicians have extended the use of the LMA-ProSealTM inside and outside the operating theatre including use for difficult airway management and airway rescue. However, even these new devices have their limitations. We report an unforeseen acute airway obstruction caused by LMA-ProSealTM malfunction during ophthalmic surgery. The cuff of the device was deformed with herniation to one side upon insufflation of the balloon.
Keywords: Laryngeal mask airway, malfunction, complications, LMA-ProSeal
INTRODUCTION Laryngeal masks are used broadly for elective
8
and emergency airway management and are
gal nerve stimulator.
an essential part of the American and Europe-
where an unanticipated airway problem arose
1-3
due to a defect in a reusable Laryngeal Mask
Due to their wide use, noticeable complica-
Airway ProSealTM (LMA-ProSealTM) when it was
tions and side effects have been reported
used for an ophthalmic procedure. Upon care-
over the last years. The rare reports of airway
ful investigation post procedure, the inflatable
obstruction directly triggered by the laryngeal
part of the device had weakened and bal-
mask are swelling of the pharyngeal soft tis-
looned out causing deformation of the mask
sues caused by the leakage of irrigation fluid,
resulting in loss of proper fit and seal.
an difficult airway management algorithm.
4
and intermittent obstruction related to a va9
We report the case
herniation of the laryngeal mask airway
cuff,
5-7
foreign bodies (Ascaris lumbricoides),
CASE REPORT A 48-year-old man with a body mass index of
Correspondence author: Binu Puthur SIMON, Department Of Anaesthesiology RIPAS Hospital, Bandar Seri Begawan BA 1710 Brunei Darussalam E mail:
[email protected]
38.9 kg/m2 was scheduled for Trans Pars Plana Vitrectomy and intra-ocular lens insertion of the left eye under general anaesthesia. His
SIMON and HABIBULAH. Brunei Int Med J. 2012; 8 (4): 206
past medical history was relevant for obs–
After this adjustment, the peak airway pres-
tructive sleep apnoea, hypertension and dia-
sure went up to 29-30cm of H2O and the
betes mellitus.
mean airway pressure was around 17cm of H2O. The end tidal CO2 was maintained at 48
The patient was pre-oxygenated with 100% oxygen for three minutes and general
to 50mm of Hg. We managed to continue with this strategy for another 40 minutes.
anaesthesia was induced with 200mgs of propofol and 75mcgs of fentanyl. Anaesthesia
Approximately 10 to 15 minutes be-
was maintained with oxygen, nitrous oxide
fore completion of surgery, breathing at-
and isoflurane. Mask ventilation was fairly
tempts by the patient were noted and we at-
easy and intravenous atracurium (40mg) was
tempted to manage the patient on spontane-
given for relaxation. A size 4 cuff LMA-
ous ventilation mode with manual assistance.
TM
ProSeal
laryngeal mask airway was suc-
It was noticed that at this point there was
cessfully placed after checking of the cuff with
hardly any end tidal CO2 trace and the reser-
30ml air insufflation. The cuff was inflated
voir bag did not show any movement. The
with 20ml of air. The patient was ventilated
patient seemed to be experiencing acute air-
with pressure controlled ventilation (PCV)
way obstruction during spontaneous attempts
mode with following parameters; inspiratory
of breathing. The patient was paralysed with a
pressure of 15cm H2O, respiratory rate of 12
10mg dose of atracurium. Volume control
per minute and an inspiratory: expiratory
mode was reinstated with the same settings
(I:E) ratio of 1:1. An I:E ratio of 1:1 was pre-
as before. The patient was then satisfactorily
ferred to achieve a higher tidal volume at a
ventilated until the surgical procedure was
lower pre-set inspiratory pressure (normal
completed.
ratio is 1:2). The patient could generate around 550mls of tidal volume with the above
An intravenous dose of neostigmine
settings. As a precautionary measure, a size
and atropine were then administered to re-
12 nasogastric tube was introduced through
verse the residual effect of the muscle relax-
the drain tube of the laryngeal mask airway
ants. When breathing attempts commenced,
(LMA). His end tidal CO2 was 35-40mm of Hg
the patient appeared to be further exhibit air-
(Normal range 35 to 45mm of Hg).
way obstruction. At this point the LMAProSealTM was removed and a Guedel airway
Thirty minutes into the surgery a
(size 4) was inserted. The patient was venti-
gradual decrease in tidal volume (350ml) and
lated with a face mask until a good respirato-
a rise in the end tidal CO2 were noted. An ad-
ry effort was observed. Further recovery was
ditional dose of atracurium (40mg) and fenta-
uneventful. The LMA-ProSealTM was later ex-
nyl (75mcgs) were given on the assumption
amined and it was noted that the cuff was
that the effect of the initial dose was wearing
deformed with herniation to one side (Figure
off, but there was no improvement. Then the
1). A faulty LMA with herniation after insuffla-
ventilator mode was changed to volume con-
tions, together with formation of a fold on the
trol with the following setting; tidal volume of
cuff was suspected as the cause of the airway
500ml and respiratory rate of 12/minute.
problem we had encountered in this case.
SIMON and HABIBULAH. Brunei Int Med J. 2012; 8 (4): 207
Figures 1: a) Inflated ProSeal
TM
showing
herniation of the right side (arrow) and b) View from the other side showing the
a
b
herniation resulting in deformation and loss of seal contour.
DISCUSSION Cases of herniation have been reported with
With intermittent positive pressure
the Classic LMA™ airway. There was a case
ventilation (IPPV) and adjustment to volume
where the plastic layers between the inflated
control we succeeded in ventilating the pa-
cuffs of a disposable LMATM had separated and
tient adequately. Since a constant flow of gas
resulted in a herniation
10
and, another case
is delivered in the volume control mode, more
where the classic reusable LMA had herniated,
tidal volume was achieved with the same air-
probably as a result of material fatigue follow-
way pressure, unlike the decelerating flow
ing repeated sterilisation.
7
noticed in pressure control mode. Moreover an airway obstruction at laryngeal inlet could
In this case, we suspected herniation
generate an auto positive end expiratory
(deformation) of the LMA occurred intra-
pressure (PEEP). This intrinsic PEEP together
operatively causing leakage around the LMA-
with long inspiratory time places the patient
ProSeal
TM
. A fold formed on the cuff facing
the laryngeal inlet (Figure 1 b). The defor-
on a less compliant (over distended) part of the volume pressure curve.
mation led to loss of proper seal causing the subsequent events.
When the patient started breathing spontaneously the obstruction became more
Though we were successful in venti-
severe causing inadequate ventilation. The
lating the patient using the volume control
reasons for almost complete airway obstruc-
mode, the peak airway pressures were high
tion once spontaneous breathing commenced
(30cm of H2O) despite administering a repeat
could be due to the deformed cuff displacing
dose of muscle relaxant. Initially we were
the LMA inlet away from the glottis. This ef-
able to get the same tidal volume at a setting
fect possibly got worse with the negative
of 15 cm H2O with pressure control mode.
pressure caused by spontaneous inspiratory
SIMON and HABIBULAH. Brunei Int Med J. 2012; 8 (4): 208
efforts. In this particular case, LMA-ProSealTM
followed in LMA–Pro SealTM prior to insertion.
was preferred over the endotracheal tube to In
obtain smooth recovery and avoid the stress of extubation occurring after posterior cham11
TM
problem
conclusion, is
when
encountered
with
a
ventilation a
reusable
was used
LMA™, particularly if this had experienced
precautionary
repeated sterilisation, a herniated cuff should
measures against aspiration and gastric dis-
be considered, even if initial testing was in-
tension (like insertion of an orogastric tube).
conspicuous.
Additionally, LMA ProSeal has proven to have
LMA™ and inspection of the cuff should be
ber eye surgery. as
we
could
LMA-ProSeal
take
extra
better seal at higher ventilating pressures.
12
7
Removal of the malfunctioning
considered to rule out this potentially deleterious technical problem.
There have been case reports of herniation of the classic reusable type LMA, pos-
AKNOWLEDGEMENT: We would like to acknow-
sibly as a result of overuse, over inflation or
ledge our colleagues, Dr Salil G NAIR, Dr Anand H
repeated sterilisation.
13
Repeated uses of
KULKARNI and Dr Hj Zulaidi HJ ABDUL LATIF for their help with the management of this patient.
LMA™ airways beyond 40 uses increases the probability of device malfunctions.
15
In this
particular case we were unable to determine
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15
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Brunei Darussalam — Healthcare in Pictures
Hj Ahmed Yunos Bin Hassan (Dresser) doing his daily round with his team in the surgical ward of the Brunei General Hospital. (Picture courtesy of Dayangku Dr Siti Nur’Ashikin Bte Pengiran Tengah).
