The Effect of Preoperative Oral Carbohydrate Loading on Insulin Resistance in Adult Patients Undergoing On-Pump Cardiac Surgery: A Randomized Controlled Trial

BACKGROUND: Preoperative oral carbohydrate loading has been shown to reduce insulin resistance in various surgical fields, but its effect in cardiac surgery remains uncertain. This study aimed to evaluate whether preoperative carbohydrate loading can reduce insulin resistance in adults undergoing on-pump cardiac surgery. METHODS: A randomized controlled trial was conducted at Dr. Sardjito Hospital, Yogyakarta, Indonesia. Fifty adults scheduled for elective cardiac surgery (January-May 2024) were randomized to receive either 400 mL of a 12.5% maltodextrin-based carbohydrate drink (CL group) or 400 mL of water 2 h before surgery (PL group). Blood glucose and insulin were measured at postinduction, 0 h, and 24 h postoperatively to calculate HOMA-IR, analyzed at a significance level of 0.05. RESULTS: Blood glucose and HOMA-IR did not differ significantly between groups at any time point (all P > 0.05). Insulin was higher in the CL group than in the PL group at postinduction ((95%CI = -6.07 to - 0.42; P = 0.022)). In the PL group, insulin rose progressively (P < 0.05), while changes in the CL group were nonsignificant (P > 0.05). HOMA-IR increased from postinduction to 0 h in both groups (P < 0.05) but remained stable thereafter (P > 0.05). CONCLUSIONS: Preoperative oral carbohydrate loading did not significantly affect perioperative glucose or HOMA-IR in cardiac surgery. While insufficient to counteract the magnitude of CPB-induced insulin resistance, carbohydrate loading may modestly stabilize metabolic responses, as reflected by a flatter insulin trajectory.