Degradation products of sevoflurane during low-flow anaesthesia.
Low-flow (1 litre min-1) sevoflurane anaesthesia was used in 16 patients undergoing laparoscopic cholecystectomy (group LSC, n = 8) or tympanoplasty (group TP, n = 8), and concentrations of sevoflurane degradation products were measured. Degradation products in the circuit were measured hourly, and end-tidal carbon dioxide concentration, inspired and end-tidal sevoflurane concentrations, and carbon dioxide elimination were monitored. The only degradation product detected was CF2=C(CF3)-O-CH2F (compound A). The mean maximum concentrations of compound A were 21.6 (SEM 1.6) ppm and 19.6 (0.8) ppm in the LSC and TP groups, respectively (ns). The maximum temperatures of soda lime were 46.4 (0.5) degrees C and 44.8 (0.5) degrees C, respectively (P < 0.05). Hourly end-tidal sevoflurane concentrations and concentrations of sevoflurane degradation products were the same for both groups. Carbon dioxide elimination was the same for both groups 1 h after the start of anaesthesia, but was higher in group LSC after 2 h (P < 0.05). Intraperitoneal carbon dioxide insufflation associated with laparoscopic cholecystectomy had no effect on the concentration of sevoflurane degradation products.
Bito
H
H
Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Japan.
Ikeda
K
K
D000328:Adult; D000368:Aged; D000777:Anesthetics / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D017081:Cholecystectomy, Laparoscopic; D004987:Ethers / Q000378:metabolism*; D006801:Humans; D008738:Methyl Ethers; D008875:Middle Aged; D000077149:Sevoflurane; D014433:Tympanoplasty
D000777:Anesthetics; D004987:Ethers; D008738:Methyl Ethers; D002245:Carbon Dioxide; D000077149:Sevoflurane