The effect of malnutrition on the metabolic response to surgery

The effect of previous malnutrition on the metabolic response to surgical hysterectomy was investigated in adult female rats. Malnutrition was achieved by feeding a 20 g protein/kg diet and restricting food intake to 50% of normal. This dietary regimen was maintained for 3 weeks before surgery and for 4 d after surgery. Unoperated control rats were pair-fed with the hysterectomized rats after surgery. Energy balance was measured by the comparative carcass technique and, in a second experiment, urinary N excretion was measured. Surgery caused energy expenditure to increase by 37% in ad libitum-fed rats but in malnourished rats it increased by only 22%. Urinary N excretion rose immediately after surgery. In the ad libitum-fed rats it was on average 85% greater in hysterectomized rats than controls for the first 3 d after surgery, whereas in the restricted rats it was 74% greater on the first day and not significantly elevated thereafter. Thus, malnutrition attenuated the metabolic response to surgery but did not abolish it completely.