Effects of minimal-flow sevoflurane anesthesia combined with Amsorb Plus calcium lime on hepatic and renal functions

Abstract

Objective To investigate the effects of minimal-flow sevoflurane anesthesia combined with a new CO2 adsorbent Amsorb Plus calcium lime on the hepatic and renal functions in patients.Methods Seventytow ASA Ⅰ or Ⅱ patients,aged 20-60 yr,scheduled for gastrointestinal surgery under general anesthesia,were randomized into 2 groups (n =36 each):middle-flow anesthesia group (group G1 ) and minimal-flow anesthesia group (group G2 ).Amsorb Plus calcium lime was added into the CO2 absorption canister and the core temperature of the calcium lime was continuously monitored and recorded.The patients were tracheal intubated after anesthesia induction and mechanically ventilated.The initial sevoflurane concentration was set at 4％ and the fresh gas flow of oxygen was set at 4 L/min.After the end-tidal concentration of sevoflurane reached 2.6％,the fresh gas flow of oxygen was adjusted to 2 L/min in group G1 or 0.5 L/min in group G2.The end-tidal concentration of sevoflurane was maintained at 2.4％-2.8％ during operation.Venous blood samples were taken 24 h before and 24 h after operation for determination of the serum concentrations of total bilirubin (TBIL),direct bilirubin (DBIL),blood urea nitrogen (BUN) and creatinire (Cr) and activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST).Urine samples were obtained at 24 h before and after operation to detect the concentration of glucose and protein.The urine glucose and protein positive patients were recorded.Results There was no significant difference in the core temperature of calcium lime at different time points between the two groups ( P ＞ 0.05 ).Compared with that at 24 h before operation,AST activity,TBIL and DBIL concentrations were significantly increased,BUN concentration was significantly decreased,but no significant change was found in the Cr concentration and the number of urine glucose and protein positive patients at 24 h after operation in group G1,and DBIL concentration was significantly increased,while BUN concentration was significantly decreased at 24 h after operation in group G2 ( P ＜ 0.05 ).There was no significant difference in the parameters of hepatic and renal functions between the two groups ( P ＞ 0.05).Conclusion The combination of minimal-flow sevoflurane anesthesia and Amsorb Plus calcium lime exerts no effect on the hepatic and renal functions,the effect is similar to that of middle-flow anesthesia,and it can be safely used in patients. Key words: Anesthetics,inhalation; Anesthesia,inhalation; Liver function tests; Kidney function tests