HYPOTHERMIA DURING ELECTIVE ABDOMINAL AORTIC-ANEURYSM REPAIR - THE HIGH PRICE OF AVOIDABLE MORBIDITY

Purpose: Adverse outcomes apparently associated with hypothermia led u s to examine patients undergoing elective abdominal aortic aneurysm (A AA) repairs to test the hypothesis that hypothermia (temperature less than 34.5 degrees C) is associated with increased morbidity and excess mortality rates. Methods: Two hundred sixty-two elective AAA repairs were retrospectively reviewed for preoperative and intraoperative risk factors. Core temperature, age, Acute Physiology and Chronic Health E valuation (APACHE) II and APACHE III scores (raw and temperature-adjus ted), fluid resuscitation, and perioperative organ dysfunction were re corded prospectively. Outcome measures included lengths of stay in the intensive care unit and in the hospital, and hospital mortality rates . Results: Except for a higher risk of hypothermia in women (p < 0.05) , by univariate analysis, preoperative risk factors were similar in pa tients in the hypothermic and normothermic groups. After operation, pa tients with hypothermia had significantly greater APACHE scores (p < 0 .0001), and patients in the hypothermic nonsurvivor group took signifi cantly longer to rewarm (p < 0.05), suggesting marked hypoperfusion. P atients with hypothermia had significantly greater fluid (p < 0.05), t ransfusion (p < 0.01), vasopressor (p < 0.05), and inotrope (p < 0.05) requirements, resulting in significantly higher incidences of organ d ysfunction (53.0% vs 28.7%, p < 0.01) and death (12.1% vs 1.5%, p < 0. 01) and markedly prolonged lengths of stay in the unit (9.2 +/- 2.0 vs 5.3 +/- 0.6, p < 0.05) and in the hospital (24.3 +/- 2.9 vs 15.0 +/- 0.08, p < 0.01). By multivariate analysis, female gender (p = 0.004) w as the only predictor of intraoperative hypothermia, whereas initial h ypothermia was significantly predictive of both prolonged hypothermia and development of organ failure (p < 0.05). Organ failure (p < 0.05) and acute myocardial infarction (p < 0.01) were independent predictors of death. Conclusions: After AAA repair, patients with hypothermia ha ve multiple physiologic derangements associated with adverse outcomes. Although multiple etiologic factors are interacting, body temperature is one variable that should be controlled during aortic surgery.