Hepatic metabolic ability during anaesthesia. Evaluation of antipyrine half-lives and their relation to enflurane metabolism.
The antipyrine (phenazone) half-life was determined in 20 surgical patients to discover whether there are changes in hepatic metabolic rate during or immediately after anaesthesia compared with the pre-anaesthetic rate. Nine patients received enflurane (mean duration 8.6, SD 2.0 hours) and six patients had a balanced anaesthetic without enflurane (duration 4.4, SD 3.3 hours). A further five patients received a spinal anaesthetic with bupivacaine. The changes in antipyrine half-life were inconsistent, and there was no evidence of competitive metabolic inhibition by general anaesthesia. Antipyrine half-lives did not correlate with serum fluoride levels or urinary fluoride excretion in the case of enflurane. The mean serum inorganic fluoride concentration rose to 29 mumol/litre, and two patients had potentially nephrotoxic concentrations (64 and 50 mumol/litre) after 8 hours of exposure to enflurane though without any evident harmful effects.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D000775:Anesthesia, Spinal; D000983:Antipyrine / Q000378:metabolism; D002045:Bupivacaine / Q000378:metabolism; D004737:Enflurane / Q000378:metabolism; D005260:Female; D005459:Fluorides / Q000378:metabolism; D006207:Half-Life; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D013997:Time Factors
D004737:Enflurane; D005459:Fluorides; D000983:Antipyrine; D002045:Bupivacaine