EFFECT OF EARLY ORAL MINERAL WATER HYDRATION ON GASTROINTESTINAL TOLERANCE AND ELECTROLYTE BALANCE AFTER CORONARY ARTERY BYPASS GRAFTING

Introduction: Postoperative oral hydration supports fluid–electrolyte balance and gastrointestinal recovery, but no standardized nutritional guidelines exist for cardiac surgery patients. Methods: This study evaluated the effect of early oral mineral water administration on gastrointestinal tolerance, electrolyte balance, and clinical outcomes after coronary artery bypass grafting (CABG). A retrospective cohort of 142 patients undergoing isolated CABG between January 2023 and June 2024 was analyzed. Patients were divided into two groups: Group 1 (n = 71) received 200 mL of chilled mineral water within two hours after extubation; Group 2 (n = 71) received standard hydration. Primary outcomes included antiemetic requirement, oral fluid tolerance, and time to first flatus. Secondary outcomes were serum electrolyte changes, atrial fibrillation incidence, and ICU length of stay. Results: Groups were comparable in demographics. Antiemetic requirement was lower in the mineral water group (21.1% vs. 71.8%, p <0.001). Oral fluid tolerance (median 5 vs. 6.5 hours, p <0.001) and first flatus (median 19 vs. 28 hours, p <0.001) occurred earlier. ICU stay was modestly but significantly shorter (p = 0.009). Postoperative magnesium (2.2 ± 0.3 vs. 1.9 ± 0.3 mmol/L, p <0.001) and potassium levels (p <0.001) were higher in the mineral water group, with significant within-group postoperative increases Conclusion: Early chilled mineral water intake after CABG was associated with better gastrointestinal tolerance, reduced antiemetic need, improved electrolyte profiles, and shorter ICU stay. Mineral water supplementation appears to be a safe and effective adjunct in postoperative cardiac care. Prospective randomized trials are needed to confirm these findings