Preoperative oral carbohydrates and postoperative insulin resistance

Infusions of carbohydrates before surgery have been shown to reduce postope rative insulin resistance. Presently, we investigated the effects of a carb ohydrate drink, given shortly before surgery, on postoperative insulin sens itivity. Methods: Insulin sensitivity and glucose turnover ([6, 6, H-2(2)]-D-glucose ) were measured using hyperinsulinemic, normoglycemic clamps before and aft er 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 surge ry. 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, th e CHO groups received 800 mi of an isoosmolar carbohydrate rich beverage th e 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 re duced 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 su rgery displayed less reduced insulin sensitivity after surgery as compared to patients undergoing surgery after an overnight fast.