Preoperative oral carbohydrates and postoperative insulin resistance

Infusions of carbohydrates before surgery have been shown to reduce postoperative insulin resistance. Presently, we investigated the effects of a carbohydrate drink, given shortly before surgery, on postoperative insulin sensitivity. Methods: Insulin sensitivity and glucose turnover ([6, 6, H-2(2)]-D-glucose) were measured using hyperinsulinemic, normoglycemic clamps before and after elective surgery. Sixteen patients undergoing total hip replacement were randomly assigned to preoperative oral carbohydrate administration (CHO-H, n = 8) or the same amount of a placebo drink (placebo, n = 8) before surgery. Insulin sensitivity was measured before and immediately after surgery. Patients undergoing elective colorectal surgery were studied before surgery and 24 h postoperatively (CHO-C (n = 7), and fasted (n = 7), groups). The fasted group underwent surgery after an overnight fast. In both studies, the CHO groups received 800 mi of an isoosmolar carbohydrate rich beverage the evening before the operation (100g carbohydrates), as well as another 400 mi (50g carbohydrates) 2 h before the initiation of anesthesia. Results: Immediately after surgery, insulin sensitivity was reduced 37% in the placebo group (P < 0.05 vs, preoperatively) while no significant change was found in the CHO-H group (-16%, p = NS). During clamps performed 24 h postoperatively, insulin sensitivity and whole-body glucose disposal was reduced in both groups, but the reduction was greater compared to that in the CHO-C group (-49 +/- 6% vs. -26 +/- 8%, P < 0.05 fasted vs. CHO-C). Conclusions: Patients given a carbohydrate drink shortly before elective surgery displayed less reduced insulin sensitivity after surgery as compared to patients undergoing surgery after an overnight fast.