Randomized clinical trial of the effect of preoperative oral carbohydrate treatment on postoperative whole-body protein and glucose kinetics

Background: Preoperative oral carbohydrate (CHO) reduces postoperative insulin resistance. In this randomized trial, the effect of CHO on postoperative whole-body protein turnover was studied. Methods: Glucose and protein kinetics ([6,6(2)H(2)]D-glucose, [H-2(5)]phenylalanine, [H-2(2)]tyrosine and [H-2(4)]tyrosine) and substrate oxidation (indirect calorimetry) were studied at baseline and during hyperinsulinaemic normoglycaemic clamping before and on the first day after colorectal resection. Fifteen patients were randomized to receive a preoperative beverage with high (125 mg/ml) or low (25 mg/ml) CHO content. Results. Three patients were excluded after the intervention, leaving six patients in each group. After surgery whole-body protein balance did not change in the high oral CHO group, whereas it was more negative in the low oral CHO group after surgery at baseline (P = 0.003) and during insulin stimulation (P = 0.005). Insulin-stimulated endogenous glucose release was similar before and after surgery in the high oral CHO group, but was higher after surgery in the low oral CHO group (P = 0.013) and compared with the high oral CHO group (P = 0.044). Conclusion: Whole-body protein balance and the suppressive effect of insulin on endogenous glucose release are better maintained when patients receive a CHO-rich beverage before surgery.