Epidural block during general anesthesia attenuates urinary trypsin inhibitor excretion in lower abdominal surgery

Purpose. The aim of this study was to elucidate whether urinary trypsin inhibitor excretion differs between general anesthesia (GA) and epidural block during general anesthesia (EPI) in lower abdominal surgery. Methods. Sixteen women undergoing abdominal total hysterectomy were assigned to the GA and EPI groups. The GA group received propofol induction and maintenance with isoflurane, nitrous oxide, and vecuronium. The EPI group received epidural block, followed by propofol induction and maintenance with isoflurane and nitrous oxide. The levels of adrenocorticotropic hormone and cortisol during anesthesia and on postoperative days 1, 2, and 3, and the levels of urinary trypsin inhibitor in 12-h urine from the day of surgery to postoperative day 3, were measured. Results. As compared with the EPI group, the GA group had a higher level of adrenocorticotropic hormone at the completion of anesthesia, higher levels of cortisol at the completion of anesthesia and postoperative day 2, and higher excretion of urinary trypsin inhibitor on the day of surgery and postoperative days 1 and 2. Conclusion. The present results suggest that excretion of urinary trypsin inhibitor into the urine under epidural block during general anesthesia is lower than that under general anesthesia alone in lower abdominal surgery. This is probably due to the difference in endocrine response to surgery between the two types of anesthesia. Received for publication on August 26, 1998; accepted on March 16, 1999