Abstract: Objective： To measure the differences of compound A（CA）between low gas flow（500ml/min）and high gas flow（2L/min），and effects on renal and liver function. Methods：The general surgical patients（n=40）were randomized to low-flow anesthesia group and high-flow anesthesia group. Gas samples were taken from the aspiratory limbs of the anesthetic circuit in 30-minites interval during anesthesia. Analyze CA concentrations. Test the markers of hepatic and renal functions pre- and post-surgery. Results：There were no statistical differences between sevoflurane concentrations（0.97vs0.97MAC）and concentration-time-AUC（2.40vs2.41MAC-h）.There were significant differences between concentrations（27.70vs11.54ppm）and concentration-time-AUC（55.76vs23.19ppm-h）.All markers of hepatic and renal function（ALT、AST、Tbil、Dbil、BUN、Cr） were unchanged after anesthesia. Conclusion：CA concentrations and concentration-time-AUC between low-flow（500ml/min）and high-flow（2L/min） anesthesia were significantly different，but it did not result in any significant changes to markers of hepatic and renal functions，including、ALT、AST、Tbil、Dbil、BUN and Cr.

Key words: anesthesia, carbon dioxide absorbent, compound A(CA), sevoflurane