The Effect of Low-Flow and High-Flow Sevoflurane Anaesthesia on Renal and Liver Function:A Comparative Study

Background and Aims: Sevoflurane degradation products can affect liver and renal functions. The study was undertaken to assess the safety of low- flow sevoflurane anaesthesia and high- flow sevoflurane anaesthesia by comparing their effects on renal and liver functions. Material and Methods: The study was conducted in 100 adult patients of American Society of Anaesthesiologists physical status I or II, who underwent elective surgery under general anaesthesia. Patients were selected randomly into two groups to receive either low-flow Sevoflurane (n=50) or high-flow Sevoflurane (n=50) anaesthesia. In all these patients, preoperative renal function tests (RFT)&liver function tests (LFT) were done. RFT included blood urea, serum creatinine, creatinine clearance, urinary protein&LFT included serum bilirubin, SGOT, SGPT, ALP. The patients were induced by intravenous thiopentone [4-7 mg/kg] and succinylcholine [1-2 mg/kg] was given to facilitate tracheal intubation. Trachea was intubated with appropriate size cuffed endotracheal tube. Anaesthesia was maintained with either highflow Sevoflurane with fresh gas flow of 4.5- 7 Liters/minute or low-flow Sevoflurane with fresh gas flow of 1- 3 L/min. Blood samples were collected before operation and at 0 hour, 06 hr, 24 hr, 48 hr&72 hr postoperatively to measure Blood urea, Serum creatinine, Creatinine Clearance (CL), serum bilirubin, Serum Glutamic Oxaloacetic Transaminases (SGOT), Serum Glutamic Pyruvic Transaminases (SGPT), Alkaline phosphatase (ALP). Urine samples were collected at 24 hrs preoperatively&every 24 hrs for up to 72 hrs postoperatively to measure urine protein. Results: This study shows alterations in renal&hepatic functions in low-flow sevoflurane anaesthesia as well as high-flow sevoflurane anaesthesia. However, the alterations in renal&hepatic functions were within upper normal limit in both groups as assessed using conventional measures of hepatic&renal functions. Conclusion: We conclude that there were no statistically significant differences in the hepato-renal function by the effect of low flow and high flow sevoflurane anaesthesia and both seem to be equally safe.