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

Objective: 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. Methods: 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 (≤34.5°C), mildly hypothermic (34.6°C-35.9°C), or mildly hyperthermic (37.5°C-38.8°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. Results: 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. Conclusion: It is important to maintain normal postsurgical core temperatures in patients who have undergone cardiac surgery to minimize or avoid death and complications.