Hepatorenal integrity following a long anesthetic exposure: a comparative study between low - flow and high - flow sevoflurane anesthesia

ABSTRACT

This study assessed the effects of low-flow sevoflurane anesthesia on renal function using BUN, serum creatinine, creatinine clearance and urinary excretion of kidney-specific enzymes, and it compared these values with those obtained in high-flow sevoflurane anesthesia. We also studied the effects of low-flow sevoflurane anesthesia and high flow on the hepatic functions. Forty male patients undergoing oculoplasty or rhinoplasty were studied. Patients were randomized to receive sevoflurane anesthesia with fresh gas flow of 1 L/min [low-flow sevoflurane group; n= 20] or 6-8 L/min [high-flow sevoflurane group; n= 20]. In both groups the carrier gas was oxygen/nitrous oxide. Soda lime was used is the low-flow sevoflurane anesthesia group, The compound A concentration was measured by gas chromatography. Blood samples were obtained before and on days 1, 2 and 3 after anesthesia to measure hepatic functions, serum electrolytes, BUN and serum creatinine. Twenty-four-hour urine samples were collected before anesthesia and for each 24-h period from 0 to 72 h after anesthesia to measure creatinine, NAG and AAP. The maximum compound A concentration was 24,7 +/- 10.1 ppm [mean +/- 80], and the average duration of exposure to this concentration was 4.55 +/- 1.88 h in the low-flow sevoflurane group, Post-anesthesia BUN and serum creatinine concentrations decreased, creatinine clearance increased, and urinary NAG and AAP excretion increased in both groups compared with preanesthesia values, but there were no significant differences between the two groups for any renal function parameter at any time after anesthesia. Total and direct bilirubin increased in the first day postanesthesia in both groups of sevoflurane anesthesia and no significant changes among the two groups, AST increased in the 2nd and 3rd postanesthesia days than the peranesthesia value but there were no significant changes among both groups of sevoflurane anesthesia. LDH increased in the three postanesthesia days than the preanesthesia values but no significant differences among both groups of sevoflurane anesthesia. We concluded that, the only difference between the low-flow and high flow sevoflurane groups was compound A formation, and postanesthesia laboratory data showed no significant effects of compound A formation during sevoflurane anesthesia on renal and hepatic functions