A. Schindler et al., Water vapour in a closed anaesthesia circuit reduces degradation/adsorption of halothane by dried soda lime, BR J ANAEST, 85(2), 2000, pp. 308-310
Citations number
6
Categorie Soggetti
Aneshtesia & Intensive Care","Medical Research Diagnosis & Treatment
Dry lime causes a loss of volatile anaesthetics by degrading and adsorbing
them. Degradation produces toxic substances and heat. Rehydration of lime s
tops degradation. If humidified breathing gases rehydrate lime, closed anae
sthesia-circuits may reduce the loss of anaesthetics. To test this hypothes
is we ventilated a reservoir bag with PhysioFlex(R)-devices using fresh (F)
and dried (D) soda lime both in the presence (+H) and absence (-H) of halo
thane. We measured halothane delivery, humidity, temperature, and lime weig
ht. Halothane was lost For 13 min in D+H. Humidity increased steeper with f
resh lime, whereas absorbent weight increased more with dried lime; halotha
ne increased both variables (F+H: 99%, 8 g; F-H: 93%, 6 g; D+H: 58%, 17 g;
D-H: 24%, 15 g). Surprisingly, temperature remained constant, probably beca
use of the high gas flow (70 litres min(-1)) generated inside the Physiofle
x(R). These findings indicate rehydration of dried lime by humid gases and
a rapid cessation of the loss of halothane in the PhysioFlex(R).