Perioperative Maintenance of Normothermia Reduces the Incidence of Morbid Cardiac Events

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Abstract
Objective. —To assess the relationship between body temperature and cardiac morbidity during the perioperative period. Design. —Randomized controlled trial comparing routine thermal care (hypothermic group) to additional supplemental warming care (normothermic group). Setting. —Operating rooms and surgical intensive care unit at an academic medical center. Subjects. —Three hundred patients undergoing abdominal, thoracic, or vascular surgical procedures who either had documented coronary artery disease or were at high risk for coronary disease. Outcome Measure. —The relative risk of a morbid cardiac event (unstable angina/ischemia, cardiac arrest, or myocardial infarction) according to thermal treatment. Cardiac outcomes were assessed in a double-blind fashion. Results. —Mean core temperature after surgery was lower in the hypothermic group (35.4±0.1°C) than in the normothermic group (36.7±0.1°C) (P<.001) and remained lower during the early postoperative period. Perioperative morbid cardiac events occurred less frequently in the normothermic group than in the hypothermic group (1.4% vs 6.3%;P=.02). Hypothermia was an independent predictor of morbid cardiac events by multivariate analysis (relative risk, 2.2; 95% confidence interval, 1.1-4.7;P=.04), indicating a 55% reduction in risk when normothermia was maintained. Postoperative ventricular tachycardia also occurred less frequently in the normothermic group than in the hypothermic group (2.4% vs 7.9%;P=.04). Conclusion. —In patients with cardiac risk factors who are undergoing noncardiac surgery, the perioperative maintenance of normothermia is associated with a reduced incidence of morbid cardiac events and ventricular tachycardia.