Robert J. Whitty, MBBCh, Gail K. Wong, MBBS,
Guy C. Petroz, MD, Carolyne Pehora, MN,
Mark W. Crawford, MBBS
Canadian Anesthesiologists’ Society 2009
Purpose
In order to establish guidelines for the preparation
of the Dra¨ger Fabius GSTM premium anesthetic workstation
for malignant hyperthermia-susceptible patients, the authors
evaluated the effect of the workstation’s exchangeable and
autoclavable components on the washout of isoflurane.
Methods
A Draeger Fabius GS workstation was primed
with 1.5% isoflurane, and exchangeable components were
replaced as follows: Group 1: no replacement (control);
Group 2: autoclaved ventilator diaphragm and ventilator
hose; Group 3: flushed ventilator diaphragm and ventilator
hose; Group 4: autoclaved compact breathing system. The
fresh gas flow (FGF) was set at 10 L min-1, and the
concentration of isoflurane in the inspiratory limb of the
circle breathing circuit was recorded every minute until an
endpoint of 5.0 parts per million (ppm) was achieved, at
which time the FGF was reduced to 3 L min-1. Six
experiments were conducted in each of the four groups.
Results
The time to achieve an isoflurane concentration
of 5.0 ppm decreased in the following order: Group 1
(151 ± 17 min)[Group 3 (137 ± 7 min)[Group 4
(122 ± 11 min)[Group 2 (42 ± 6 min) (P\0.01 vs
control). Isoflurane concentration increased approximately
fivefold when the FGF was reduced to 3 L min-1.
Conclusion
Anesthetic washout from the Draeger Fabius
GS is relatively slow. Although washout was accelerated
when the Draeger Fabius GS was equipped with autoclaved
components, the reduction in washout time may be
less than that required for this technique to be accepted
into clinical practice. A dedicated vapor-free workstation may be preferable for rapid turnover between cases.
