The Influence of Preoperative Fasting on the Survival of Rats Induced by 90% Hepatectomy

Abstract

Purpose: To study whether preoperative fasting would influence postoperative prognosis and to measure the variation of the ketone body amount and ketone body ratio, kidney function during the postoperative period in the model of 90% hepatectomy.

Materials and Methods:: Total of 180, seven weeks old, male, specific pathogen free Sprague-Dawley rats, divided into two groups of the fasted and the fed. First, 80 rats were divided into two groups of 40 each; 40 of that were denied food for 48 hours before the operation, other 40 were fed. Following 90% hepatectomy they were investigated by Kaplan-Meier method, drawing a survival curve. Secondly, 100 rats were divided into two groups of 50 each, 50 of that were denied food for 48 hours before the operation, and the other 50 were fed. Following 90% hepatectomy, they were investigated by the method of Student’s T-test and Mann-Whitney test on the following: the amount of arterial ketone body in the blood in the blood sampled from abdominal aorta, reading at preoperative 48 hours, at the time of operation, postoperative 6 hours, 12 hours, 24 hours, 48 hours periods.

Results: The mean survival time after operation: the fasted group was 53.0+/-3.7 hours and the fed group was 34+/-1.7 hours and it had the statistical significance(p=0.0008). Rats which had long term survival over 72 hours were 14(35%) in fasted group, but only 2(5%) in fed group. In preoperative fasted group arterial ketone body ratio was recovered earlier than fed group and ketone body amount elevated, but in preoperative fed group, there was no significant change in ketone body amount. Blood glucose level lowered in both groups. Blood ammonia was severely increased in preoperative fed group, suggested bad liver function and destruction of muscle. BUN and blood creatinine was elevated in preoperative fed group, suggested lowered kidney function.

Conclusion: Preoperative fasting has a positive influence on survival of the rats which has acute liver failure induced by 90% hepatectomy, because it could be caused by increased ketone body amount by preoperative fasting.