Insulin Resistance Improvement After Cardiac Surgery by Preoperative Carbohydrate Loading: A Randomized Controlled Trial

Background: The idea of preoperative overnight fasting was challenged and verified to have no benefits compared with drinking clear liquids up until 2 hours before surgery. In this study, we explored the possible effects of preoperative oral carbohydrate loading (OCL) on insulin resistance and the clinical outcomes of patients undergoing cardiac surgery. Methods: Totally, 260 patients were recruited and allocated randomly to intervention (n=130) and control (n=130) groups. The intervention group received 250 mL of an oral carbohydrate fluid containing 25 g of glucose, and the control group received standard care. Insulin resistance, glycemic indices, and clinical outcomes were assessed before and after surgery. Results: Totally, 107 patients in the intervention group and 103 in the control group completed the study and were, thus, included in the final analysis. Preoperative OCL 2 hours before surgery improved postoperative fasting blood sugar and clinical outcomes after cardiac surgery including thirst, hunger, anxiety, pain, the length of stay in the hospital, and the length of stay in the ICU (all Ps<0.05). Conclusions: OCL administered preoperatively seems to be beneficial in improving the biochemical and clinical outcomes of patients undergoing cardiac surgery. Notably, preoperative OCL as a safe, simple, and cost-benefit approach is associated with no or negligible harm and, therefore, could be recommended in the setting of cardiac surgery, with careful attention to contraindications.