Impact of Preoperative Oral Carbohydrate Loading on Insulin Resistance in Pediatric Cardiac Surgery Patients

Overview

Surgical stress and preoperative fasting can induce insulin resistance, characterized by impaired cellular response to insulin and resulting hyperglycemia. In pediatric patients undergoing cardiac surgery, this metabolic stress response may negatively affect postoperative recovery. Although preoperative oral carbohydrate loading, defined as administering a carbohydrate-rich beverage before surgery rather than prolonged fasting, has demonstrated efficacy in reducing postoperative insulin resistance in adults, evidence supporting its use in pediatric cardiac surgery remains limited. This randomized controlled trial aims to determine whether preoperative oral carbohydrate loading reduces perioperative insulin resistance, as measured by the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), in pediatric patients undergoing cardiac surgery. The study will compare outcomes between children who receive an oral carbohydrate beverage prior to surgery and those who follow standard preoperative fasting protocols.

This study is a prospective, single-blind, randomized controlled trial of pediatric patients who underwent elective cardiac surgery at Dr. Sardjito General Hospital, Yogyakarta, Indonesia, from April to August 2026. The study sample consisted of pediatric patients aged 2-16 years with an ASA physical status of 2 or 3 who had good tolerance for enteral fluid administration. Patients will be randomly assigned to one of two groups: 1. Intervention Group (Carbohydrate Loading): 3 mL/kg body weight of a maltodextrin-based carbohydrate drink 2 hours before anesthesia; 2. Control Group (Placebo Loading): 3 mL/kg body weight of plain water 2 hours before anesthesia. All patients will follow standard preoperative fasting guidelines. Blood samples for glucose and insulin testing will be collected immediately after induction (baseline), at 0 hours of Intensive Care Unit (ICU) admission, and at 24 hours of ICU admission. The primary outcome is the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Secondary outcomes include blood glucose levels, serum insulin concentration, exogenous insulin dose, and glycemic variability. All study participants will undergo preoperative assessment, followed by a carbohydrate-loading protocol, and assessment of blood glucose levels, insulin resistance, exogenous insulin administration, and intraoperative and postoperative glycemic variability. Numerical data will be presented as means and standard deviations. Categorical data will be presented as counts and percentages. The Shapiro-Wilk normality test will be applied to all numerical data. Subject characteristics between the two groups will be compared using the Chi-square test for categorical data and the t-test (for normally distributed data) or the Mann-Whitney test (for non-normally distributed data) for numerical data. Pre- and postoperative HOMA-IR values will be compared using a paired t-test if the data are normally distributed, or a two-way ANCOVA (univariate GLM) if they are not. A p-value \< 0.05 will be considered statistically significant.