Renal effects and metabolism of isoflurane in man

Abstract

The intra- and postanesthetic renal effects and metabolism of isoflurane were studied in 9 surgical patients; 6 control patients received halothane. Isoflurane was metabolized to a slight extent, with a mean peak serum inorganic fluoride concentration of 4.4±0.4 μM/l, measured 6 hr after anesthesia. Dose related increases of inorganic and organic fluoride were found in the urine. At comparable anesthetic exposures 5 to 10 times more organic fluoride metabolites of halothane were detected. Postanesthetic renal function, including the response to vasopressin, was normal in both groups. Intra anesthetic depressions of renal blood flow (51% of control), glomerular filtration rate (63% of control) and urinary flow rate (34% of control) during isoflurane anesthesia were similar to those seen with halothane. Metabolism of isoflurane to inorganic fluoride is of insufficient magnitude to cause renal dysfunction.