Effect of “preoperative” oral carbohydrate treatment on insulin action—a randomised cross-over unblinded study in healthy subjects

Background & aims Preoperative intake of a clear carbohydrate-rich drink reduces insulin resistance after surgery. In this study, we evaluated whether this could be related to increased insulin sensitivity at the onset of surgery. Furthermore, we aimed to establish the optimal dose-regimen. Methods Six healthy volunteers underwent hyperinsulinaemic (0.8 mU/kg/min), normoglycaemic (4.5 mmol/l) clamps and indirect calorimetry on four occasions in a crossover-randomised order; after overnight fasting (CC), after a single evening dose (800 ml) of the drink (LC), after a single morning dose (400 ml, CL) and after intake of the drink in the evening and in the morning before the clamp (LL). Data are presented as mean±SD. Statistical analysis was performed using the Studentʹs t-test and ANOVA. Results Insulin sensitivity was higher in CL and LL (9.2±1.5 and 9.3±1.9 mg/kg/min, respectively) compared to CC and LC (6.1±1.6 and 6.6±1.9 mg/kg/min, P<0.01 vs. CL and LL). Conclusions A carbohydrate-rich drink enhances insulin action 3 h later by approximately 50%. Enhanced insulin action to normal postprandial day-time level at the time of onset of anaesthesia or surgery is likely to, at least partly, explain the effects on postoperative insulin resistance.