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April
1998
High
concentration versus incremental induction of anesthesia with sevoflurane
in children: a comparison of induction times, vital signs, and complications.
Epstein RH, Stein AL, Marr AT, Lessin JB;
Journal of Clinical Anesthesia 1998;10:41-45.
[ see
abstract below ]
Epstein et al compared two techniques for the gaseous induction of anesthesia
in children. They clearly demonstrated a more rapid induction in the 8%
sevoflurane group when compared with the incremental sevoflurane concentration
induction technique. Although this difference was statistically different
at the 0.01 level, the actual time difference was only a mean of 24 seconds.
At first glance, this time difference may not appear to be clinically
important. However these authors have made two very important observations:
1) crying children are induced more rapidly that non-crying children,
2) younger children are induced more rapidly than older children. When
one is attempting to rapidly anesthetize a young frightened child it is
important to minimize the duration of that frightening experience; this
study clearly demonstrates that using a high concentration of sevoflurane
accomplishes this goal.
There is however one other very important issue that must not be forgotten,
i.e. what psychologic trauma are we inflicting when we perform a gaseous
induction in the unpremedicated frightened child - what we used to call
a "brutane" induction? I have heard a number of colleagues
around the country talk about no longer needing to premedicate their patients
"because a sevoflurane induction is so fast that the child does
not need premedication"
I am very concerned when I hear this kind of discussion because I fear
that we are trading convenience for us, ( not premedicating and not having
to wait for the premedication to have its effect), for a potentially long
term psychologic trauma in the child (held down and smothered). I would
ask that we not abandon premedication for our convenience, especially
with medications that may block the memory of the event. Every year since
I have been in practice I have had at least one older child tell me that
they would prefer an intravenous induction because in the past, when they
were younger, someone had held them down and "smothered"
them. I hope that we remember to treat this vulnerable population with
the consideration they merit and use premedication liberally, especially
in the toddlers who can understand but are not able to protest what they
don't like other than by crying.
Return to the Current Literature Review
Front Page , or read the abstract:
ABSTRACT
Study Objective: To compare sevoflurane induction times and complications
in children during a high concentration, primed-circuit method and an incremental
induction technique.
Design: Randomized, prospective open-labeled study.
Setting: Academic university hospital.
Patients: 40 unpremedicated ASA physical status I and II children
aged 4 months to 13 years undergoing elective surgical procedures with general
anesthesia.
Interventions: Patients were randomized to one of two study groups.
In the high concentration group, the anesthesia circuit was primed with
8% sevoflurane in a 2:1 nitrous oxide:oxygen (N2O:O2)
mixture. Patients breathed this gas mixture spontaneously until loss of
the eyelash reflex. In the incremental group, the face mask was applied
and 1% sevoflurane in a 2:1 N2O:O2 mixture was administered.
In this group, the sevoflurane concentration was increased by 1% every 2
to 3 breaths. Gas flows of 6L/min were administered in both groups during
the study period. Following loss of the eyelash reflex, the sevoflurane
concentration was decreased to 5% until a depth of anesthesia sufficient
to start an intravenous catheter was achieved.
Measurements and Main Results: Induction cooperation, induction time
(face mask application to loss of the eye lash reflex), one-minute vital
signs [blood pressure, heart rate, oxygen saturation via pulse oximetry
(SpO2)], induction complications. Induction of anesthesia was
faster in the high concentration group than in the incremental group (mean
(SD) 42 (9) sec vs. 66 (12) sec respectively; p<0.001). Induction complications
were minor and occurred with similar frequencies (4/20 patients vs. 3/20
patients). There were no significant intergroup heart rate, blood pressure,
or SpO2 differences during induction. No patients required treatment
for hypotension or bradycardia.
Conclusions: In healthy pediatric patients undergoing mask induction
of general anesthesia with sevoflurane, the induction time can be significantly
shortened without an increase in the frequency of airway or vital sign complications
using a higher concentration.
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