Serum and urinary inorganic fluoride concentrations with renal and hepatic functions after repeated sevoflurane anesthesia

The purpose of this study is to examine changes in serum and urinary inorganic fluoride (F) concentrations with their effects on renal and hepatic functions after repeated sevoflurane anesthesia with relatively short time interval. Eight patients received sevoflurane anesthesia twice within 7 days for gynecological surgery. Serum and urine F levels before induction, 0.5 and 1 hour after induction, and 0.5 hour after anesthesia were compared between first and second anesthesia. There were no significant differences in serum and urine F concentrations at the same point between first and second anesthesia. Two obese patients exhibited peak concentrations greater than 50 μmol·l^-1 of F. Laboratory findings of renal function remained stable throughout 2 operations, whereas hepatic function deteriorated in the two obese patients after the first anesthesia, and resolved within 14 days after the second anesthesia. In conclusion, it is suggested that the second exposure to sevoflurane within 7 day interval does not alter the sevoflurane metabolism. However, obesity may contribute to a rise in serum inorganic fluoride after repeated sevoflurane anesthesia.