Abstract :
Background: The reports concerning the potential of sevoflurane to inflict renal injury in humans display conflicting results. In some investigations, sevoflurane was reported to have effects on renal function, but others were in contradiction. Hepatic degradation of sevoflurane liberates inorganic fluoride ions (F-) and the principle organic byproduct hexafluoroisopropanol (HEIP), which accounts for 82% of the organic fluorinated metabolites. Safety of low flow sevoflurane anesthesia has been investigated for patients with renal which showed a debate and its use for prolonged anesthesia with these patients needs more investigations. Aim of this work is to compare the effects of prolonged low flow versus high flow sevoflurane anesthesia on serum free fluoride ion level and on renal and hepatic functions of primarily renal impaired patients. Methods: Our study included forty four hospitalized patients who were expected to undergo elective prolonged ( 5 hours) plastic operations. All patients were of ASA grade II or III, their ages were between 18 – 50 years, with serum creatinine more than 1.3 mgdl (and less than 2.5 mgdl), and their creatinine clearance was more than 50%, Patients had signed fully informed written consent after the nature and purpose of the study had been fully explained. The systolic and diastolic blood pressures, heart rate were recorded throughout the procedure, blood samples ware extracted from each patient 24 hours preoperatively for base line laboratory evaluation and intraoperatively (3 and 5 hours from induction) and at 6, 12 hours postoperatively for measuring serum inorganic fluoride. Also blood samples were collected 24, 48 and 72 hours postoperatively for measuring serum inorganic fluoride and for total bilirubin, alkaline phosphates, AST, ALT., B.U.N., serum creatinine, lactate dehydrogenase, prothrombin time. A 24 hours urine sample was collected from each patient for: creatinine clearance, urine albumin and urine specific gravity. Results: Regarding serum fluoride ions, renal and hepatic functions, no significant differences were detected between the two groups at the preoperative period (T0) or at any time in the postoperative period. The changes of the serum fluoride ions through the study in each of the two groups were highly significant. Regarding renal functions in group I; for serum creatinine, blood urea nitrogen, creatinine clearance and urine specific gravity, the changes were not significant, while for urine albumin the changes were highly significant. Regarding hepatic functions, in both groups the changes of the serum A.S.T, serum A.L.T, serum lactate dehydrogenase and total bilirubin through the study were highly significant, while the changes of the serum alkaline phosphatase and prothrombin time were not significant. Conclusion: Surgical patients with renal impairment who received prolonged low or high flow sevoflurane anesthesia showed evidence of transient hepatorenal dysfunction postoperatively, but these were mild and subclinical abnormalities. It is unlikely that serum fluoride ion concentration played a significant rule.We concluded that prolonged anesthesia to patients with mild renal impairment with low flow sevoflurane has similar effects on hepatorenal functions as prolonged anesthesia with high flow sevoflurane.
