The effect of heat-moisture exchanger and closed-circuit technique on airway climate during desflurane anesthesia.
OBJECTIVE
We assessed whether closed-circuit anesthesia (CCA) could provide a more favorable airway climate than semi-closed anesthesia (SCA), and we also determined the beneficial effect of heat moisture exchangers (HMEs) on the preservation of airway climate during desflurane anesthesia.


METHODS
Forty patients scheduled for colorectal surgery (n = 10 for each group) were randomized to receive a fresh gas flow of 250 or 3000 ml.min(-1) with or without HMEs. Anesthesia was maintained by adjusting the inspired concentration of 6% desflurane. Absolute moisture and temperature of inspired gases were measured as the baseline value first at 5 min after tracheal intubation, and then at 10, 20, 45, 60, 90, and 120 min after the induction of anesthesia.


RESULTS
At 120 min, the inspiratory humidity and temperature were higher in CCA than in SCA. The HME led to major improvements of the humidity (from 22.1 to 35.7 mg H(2)O.l(-1)) and temperature (from 23.6 degrees C to 31.5 degrees C) of anesthetic gases in the CCA group.


CONCLUSIONS
CCA was much more advantageous than SCA for maintaining the patient's airway climate during the 2-h study. The beneficial effect of HME on the airway climate should be emphasized, especially in patients undergoing general anesthesia.
Lu
Chih-Cherng
CC
Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Ho
Shung-Tai
ST
Liaw
Wen-Jinn
WJ
Chen
Ruei-Ming
RM
Chen
Ta-Liang
TL
Lin
Chung-Yuan
CY
D000328:Adult; D000764:Anesthesia, Closed-Circuit / Q000295:instrumentation / Q000379:methods; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D000077335:Desflurane; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007442:Intubation, Intratracheal / Q000295:instrumentation; D007530:Isoflurane / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D012119:Respiration; D013696:Temperature; D013997:Time Factors
D018685:Anesthetics, Inhalation; D000077335:Desflurane; D007530:Isoflurane