Clinical Impact of Intraoperative Temperature Strategy in CABG: A Normothermic Advantage

Background The optimal temperature strategy during cardiopulmonary bypass (CPB) for coronary artery bypass grafting (CABG) remains debated. We compared perioperative outcomes between normothermic and hypothermic CPB in a single‐center cohort in Iran. Methods A retrospective cohort of 98 consecutive adults were undergoing isolated, on‐pump CABG at Razi Hospital (March 2020–March 2021). Patients were grouped by intraoperative temperature strategy (normothermia 35°C–37°C without topical cooling vs. hypothermia 28°C–32°C with topical cooling as used). Data were abstracted from charts using a predefined checklist (demographics/comorbidities, operative details, intra‐/postoperative transfusion and fluid balance, electrolytes/renal indices, complete blood count, ICU/ward length of stay, 12 h core temperature, mortality, and neurological events). Two‐sided tests were used with α = 0.05. Results Groups were balanced in baseline characteristics. Compared to normothermia, hypothermia required more intraoperative packed cells (mean: 476 vs. 191 mL; p < 0.001), while postoperative transfusion until discharge was similar (636 vs. 560 mL; p = 0.42). ICU (2.2 vs. 1.9 days; p < 0.001) and ward stay (5.4 vs. 3.8 days; p < 0.001) were longer with hypothermia. Postoperative sodium increased in normothermia ( p < 0.001) but not in hypothermia ( p = 0.173); both groups showed increased urea/creatinine and decreased RBC/Hb/Hct postoperatively. Serum intake and urine output were higher intra‐ and postoperatively in hypothermia (all p < 0.001). Ejection fraction and 12‐h core temperature did not differ; mortality and CVA were rare and comparable. Conclusion In this cohort, normothermic CPB for isolated CABG was associated with fewer intraoperative transfusions and shorter ICU/ward stays than hypothermia, with otherwise similar short‐term safety signals. Prospective studies should test long‐term and patient‐reported outcomes.