[Value of microalbuminuria in fluid balance after abdominal surgery]

To evaluate the relationship among the microalbuminuria, surgical stress and postoperative fluid balance after abdominal surgery.

A total of 191 patients undergoing an elective abdominal operation were studied. According to the extent of operative trauma, all patients were divided into 4 groups. GroupI: laparoscopic cholecystectomy (n=64); Group II: laparotomy of cholecyst and biliary tract (n=36); Group III: radical surgery of colorectal cancer (n=43); Group IV: distal subtotal gastrectomy (D2) or total gastectomy (D3) or pancreaticoduodenectomy (n=48). The operative severities were predicated by surgical stress score (SSS). Urine albumin-creatinine ratio (ACR) was measured at both pre- and post-operation. The levels of ACR were compared by ANOVA among these 4 groups. The correlation of ACR and SSS was analyzed. In Groups III and IV, body weight was measured by weight-bed simultaneously. The correlation of variation of ACR at 0 and 6 hours post-operation (ΔACR) and the volume of positive fluid balance in the first 24 hour post-operation were studied. We also compared the varied durations of ACR levels returning to normal or the pre-operative level and body weight reaching peak values.

The levels of ACR increased in all groups. The level of ACR was the highest in Group IV and the lowest in Group I, significantly different from the levels of group II and III. There was a significant positive correlation between the increase in ACR and the severity of surgical trauma as measured by SSS. A positive correlation was observed between the volume of positive fluid balance in the first 24 hour post-operation and ΔACR at 0 and 6 hours post-operation. The varied duration of ACR levels returning normal or the pre-operative level was earlier than that of reaching the peak values.

ACR has a positive correlation with the extent of surgical stress and volume of positive fluid balance. The fact that the ACR comes earlier than the change of body weight indicates that the change of ACR is a more sensitive and simpler parameter than body weight to predict the onset of negative fluid balance.