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USE OF MANOMETRY FOR
LARYNGEAL MASK
AIRWAY REDUCES
> POSTOPERATIVE
PHARYNGEAL ADVERSE
EVENTS
>
> Anesthesiology
2010;112:652-7 Seet
E, Yousaf F, Gupta
S,
> Subramanyam R,
Wong DT, Chung F
>
>
Abstract
>
> Purpose The
purpose of this
study was to
> compare the
difference in the
incidence of
pharyngolaryngeal
> complications in
ambulatory surgical
patients whose
> laryngeal mask
airway (LMA)
intracuff pressure
was managed
> with manometry to
limit inflation
pressure to those
who had
> routine cuff
inflation without
manometry.
>
> Background LMAs
are routinely used
for
> airway management.
Serious
complications are
rare; however
> pharyngolaryngeal
adverse events such
as sore throat are
> common, with
reported incidences
as high as 42%. High
> intracuff
pressures, > 60 cm
H20 or 44 mm Hg have
been
> associated with
serious cranial
nerve injuries
secondary to
> LMA cuff over
inflation.
Unfortunately,
routine monitoring
> of intracuff
pressure with a
manometer is not
common
> practice.
>
> Methodology
Ambulatory surgical
patients,
> aged 18-60 years
with ASA physical
status I-III were
> recruited.
Subjects were
randomly assigned to
routine care
> or
pressure-limited to
<60 cm H20 or 44 mm
Hg. A
> standardized
anesthetic technique
was used for all
patients.
> Anesthesia was
induced with
propofol and
fentanyl and an LMA
> was inserted by an
experienced
clinician, followed
by
> maintenance with
desflurane and an
air-oxygen mixture.
> Fentanyl was
titrated as needed
and patients were
allowed to
> breathe
spontaneously.
Research assistants
measured cuff
> pressure. Cuff
pressure for
subjects in the
treatment group
> was kept < 60 cm
H20 or 44 mm Hg. The
incidence of sore
> throat, dysphagia,
and dysphonia was
evaluated by a
blinded
> research assistant
at 1, 2 and 24 hours
postoperatively. The
> primary outcome of
composite
pharyngolaryngeal
complications
> (sore throat +
dysphagia +
dysphonia) was
compared between
> the two groups
using a chi square
test. Logistic
regression
> was used to asses
risk factors
associated with
> pharyngolaryngeal
complications.
>
> Result A total of
203 subjects
completed
> the study
(pressure limited
group n = 97,
routine care group
> n = 103). No
differences in
baseline
demographics or
> perioperative data
were found between
groups. Immediately
> after LMA
insertion, cuff
pressure averaged
112 ± 59 mm Hg
> in the
pressure-limited
group compared to
114 ± 57 mm Hg in
> the routine care
group. After
adjustment of
intracuff
> pressure in the
pressure-limited
group, cuff pressure
was
> significantly
lower than the
control group (40 ±
6 vs. 114
> ± 57 mm Hg, P <
0.001). Composite
pharyngolaryngeal
> adverse events
were significantly
less frequent in the
> pressure-limited
group (13.4% vs.
45.6%, P < 0.001).
Use
> of manometry
decreased the
relative risk of
complications by
> 70.6% with a
number needed to
treat of 3 (95% CI
2.2- 7.5)
> needed to prevent
complications with
the pressure-limited
> group. The
incidence of sore
throat was
significantly less
> at 2 hours (2.1%
vs. 8.7%, P <0.05)
and 24 hours (3.1%
> vs. 13.6%, P <
0.05) in the
pressure-limited
group.
> Dysphagia was
significantly less
at all three time
points (1
> h: 1% vs. 12.6%; 2
h: 0% vs. 12.6%; 24
h: 2.1% vs. 8.7%, P
> < 0.05), whereas
dysphonia was only
significantly less
at
> 1 hour (5.2% vs.
15.5%, P < 0.05).
Logistic regression
> revealed that the
only variable
predictive of
> pharyngolaryngeal
complications was
intracuff pressure
(P =
> 0.0001). Clinical
experience, number
of insertion
attempts,
> ease of insertion,
blood on LMA,
duration of surgery,
use of
> an oral airway,
incidence of
larygospasm, and
suctioning
> were not
associated with
complications.
>
> Conclusion Use of
a manometer to keep
LMA
> intracuff pressure
< 60 cm H20 or 44 mm
Hg significantly
> decreased the
incidence of sore
throat, dysphagia
and
> dysphonia in
ambulatory surgical
patients allowed to
> spontaneously
breathe under
general anesthesia
with
> desflurane and
air-oxygen mixture.
The authors
recommended
> the routine use of
a pressure manometer
to keep LMA
> intracuff
pressures < 60 cm
H20 or 44 mm Hg.
>
> Comment
>
> This was a well
designed
prospective,
randomized trial
> which provides
compelling evidence
for keeping LMA
intracuff
> pressures < 60 cm
H20 or 44 mm Hg to
limit the incidence
> of
pharyngolaryngeal
complications. I was
amazed at how LMA
> intracuff
pressures in both
groups after
placement were
> almost two times
the manufactures’
recommendation for
> intracuff pressure
(< 60 cm H20 or 44
mm Hg). In this day
> of increasing
ambulatory surgery I
think it is
important
> that we continue
to find ways to
decrease
complications and
> improve outcomes.
I don’t think we
will ever find a way
to
> completely
eliminate the
incidence of sore
throat after use
> of an LMA (or
intubation); however
anything we can do
> certainly may
help. After reading
this study I began
using a
> manometer
routinely with LMAs
and found that my
intracuff
> pressures were
still higher than
what is recommended,
so I
> now use the
manometer to keep
the pressure less
than 60 cm
> H20 or 44 mm Hg.
Likewise, I teach my
students to
routinely
> use a manometer
and to keep cuff
pressures below
recommended
> maximum pressure.
>
> Dennis Spence,
PhD, CRNA
>
> The views
expressed in this
article are those of
the author
> and do not reflect
official policy or
position of the
> Department of the
Navy, Department of
Defense or the
United
> States Government.
>
> © Copyright 2010
Anesthesia Abstracts
· Volume 4 Number
> 3, March 28, 2010
>
>
...................................................................................................................................................................................................................................
> Charlene Burk
> Administrative
Assistant
> Lifelong Learning,
LLC
> charlie@lifelonglearningllc.com
>
>
>
>
www.LifelongLearningLLC.com |
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