Renal integrity in sevoflurane sedation in the intensive care unit with the anesthetic-conserving device: a comparison with intravenous propofol sedation.

BACKGROUND: Increased inorganic fluoride levels after methoxyflurane exposure in the 1970s and prolonged intraoperative sevoflurane use have been suggested to be potentially nephrotoxic. In the intensive care unit we evaluated the effect on renal integrity of short-term inhaled postoperative sedation with sevoflurane using the Anesthetic Conserving Device (ACD) compared with propofol. METHODS: In this prospective, randomized, single-blinded study, after major abdominal, vascular or thoracic surgery 125 patients were allocated to receive either sevoflurane (n = 64) via the ACD (end-tidal 0.5-1 vol%) or i.v. propofol (n = 61) for postoperative sedation up to 24 h. Urinary alpha-glutathione-s-transferase as primary outcome variable, urinary N-acetyl-glucosaminidase, serum creatinine, and inorganic fluoride concentrations, urine output and fluid management were measured preoperatively, at the end of surgery, and at 24 and 48 h postoperatively. RESULTS: The sedation time in the intensive care unit was comparable between the sevoflurane (9.2 +/- 4.3 h) and the propofol (9.3 +/- 4.7 h) group. Alpha-glutathione-s-transferase levels were significantly increased at 24 and 48 h postoperatively compared with preoperative values in both groups, without significant differences between the groups. N-acetyl-glucosaminidase and serum creatinine remained unchanged in both study groups, and urine output and creatinine clearance were comparable between the groups throughout the study period. Inorganic fluoride levels increased significantly (P < 0.001) at 24 h after sevoflurane exposure (39 +/- 25 micromol/L) compared with propofol (3 +/- 6 micromol/L) and remained elevated 48 h later (33 +/- 26 vs 3 +/- 5 micromol/L). One patient in each group suffered from renal insufficiency, requiring intensive diuretic therapy, but not dialysis, during hospital stay. CONCLUSIONS: Short-term sedation with either sevoflurane using ACD or propofol did not negatively affect renal function postoperatively. Although inorganic fluoride levels were elevated after sevoflurane exposure, glomerular and tubular renal integrity were preserved throughout the hospital stay.