The relationship between perioperative temperature and adverse outcomes after off-pump coronary artery bypass graft surgery

Abstract

The study objective was to determine predictors of hypothermia and hyperthermia, and the impact of hypothermia and hyperthermia on postoperative outcomes for off-pump coronary artery bypass grafting. We performed a retrospective study of 2294 patients who underwent off-pump coronary artery bypass grafting in New York in 2007. Patients were classified as moderately to severely hypothermic (< or = 34.5 degrees C), mildly hypothermic (34.6 degrees C-35.9 degrees C), or mildly hyperthermic (37.5 degrees C-38.8 degrees C) after leaving the operating room. Significant independent predictors of these temperature states and the independent impact of each of these states on in-hospital mortality and complications were identified. A total of 37.7% of patients were mildly hypothermic, 9.0% of patients were moderately to severely hypothermic, and 5.6% of patients were mildly hyperthermic. Significant independent predictors for postoperative hypothermia included older age, female gender, lower body surface area, congestive heart failure, higher ventricular function, non-Hispanic ethnicity, single/double-vessel disease, low postoperative hematocrit, previous cardiac surgery, race other than white or black, and organ transplant. Patients with moderate to severe hypothermia had significantly higher risk-adjusted in-hospital mortality than patients with normothermia (adjusted odds ratio 3.00; 95% confidence interval, 1.11-8.08). Patients with mild hyperthermia also had significantly higher mortality (adjusted odds ratio 5.04; 95% confidence interval,1.18-21.55). Patients with either mild or moderate to severe hypothermia had significantly higher rates of respiratory failure and unplanned operations, and patients with mild hyperthermia had a significantly higher rate of respiratory failure than normothermic patients. It is important to maintain normal postsurgical core temperatures in patients who have undergone cardiac surgery to minimize or avoid death and complications.