Analysis of ethanol in expired air during low-flow isoflurane anaesthesia.
Monitoring of ethanol concentration in expired air is a method for assessing fluid absorption during transurethral prostatic surgery and endometrial resection, but the validity of this technique has not been studied in low-flow ventilation systems. For this purpose, we have compared the concentration-time profiles of ethanol in expired gas and in venous blood during an i.v. infusion of 0.4 g kg-1 of ethanol over 30 min in 10 women during isoflurane anaesthesia and in the awake state. Anaesthesia increased the ethanol concentration in expired gas by 13% and in venous blood by 34%. The expired gas-blood difference during infusion was abolished, and the central volume of distribution for ethanol was reduced from 20.9 to 8.6 litre, on average. We conclude that breath sampling during low-flow isoflurane anaesthesia reflects an alcohol load well, but that a change in ethanol disposition makes the values slightly higher than in the awake state.
Olsson
J
J
Department of Anaesthesia, Sundsvall Central Hospital, Sweden.
Hahn
R G
RG
D000328:Adult; D000388:Air / Q000032:analysis*; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation; D001944:Breath Tests; D003243:Consciousness; D000431:Ethanol / Q000032:analysis* / Q000097:blood / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007530:Isoflurane; D008875:Middle Aged; D014882:Water-Electrolyte Balance
D018685:Anesthetics, Inhalation; D000431:Ethanol; D007530:Isoflurane