Renal functions and serum fluoride concentrations in chronic renal failure patients after sevoflurane or isoflurane anaesthesia

ABSTRACT

Sevoflurane is metabolised to hexa-fluoro-isopropanol and inorganic fluoride ions by human liver. The peak plasma fluoride level is higher after sevoflurane than after isoflurane. Although this has no effect on renal functions in normal patients and volunteers, it might be risky on those with chronic renal insufficiency. In this study, 60 patients with stable chronic renal insufficiency who required surgical intervention were randomly allocated into one of two groups each of 30 patients; sevoflurane and isoflurane groups. We compared the renal functions [serum creatinine, urea, osmolality, sodium and urine osmolality] and the serum inorganic fluoride levels afler sevoflurane to those after isoflurane anaesthesia. Peak serum inorganic fluoride concentrations were significantly higher after sevoflurane than after isoflurane anesthesia [26 +/- 3 Vs 14 +/- 2 um/L]. Laboratory measures or renal functions remained stable throughout the postoperative period in both groups. No patient suffered a permanent renal damage of preexisting renal insufficiency and non required postoperative dialysis. There is no evidence that the increased fluoride levels after sevoflurane worsened the preexisting renal impairment. We concluded that the increase in serum inorganic fluoride after sevoflurane to levels as seen in this study are of little risk to patients with chronic renal insufficiency. Further studies to evaluate the effect of compound A on the renal functions on those chronic renal impairment patients are required