Hypothermia during elective abdominal aortic aneurysm repair: the high price of avoidable morbidity.
OBJECTIVE
Adverse outcomes apparently associated with hypothermia led us to examine patients undergoing elective abdominal aortic aneurysm (AAA) 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 Evaluation (APACHE) II and APACHE III scores (raw and temperature-adjusted), fluid resuscitation, and perioperative organ dysfunction were recorded 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 patients in the hypothermic and normothermic groups. After operation, patients with hypothermia had significantly greater APACHE scores (p < 0.0001), and patients in the hypothermic nonsurvivor group took significantly longer to rewarm (p < 0.05), suggesting marked hypoperfusion. Patients with hypothermia had significantly greater fluid (p < 0.05), transfusion (p < 0.01), vasopressor (p < 0.05), and inotrope (p < 0.05) requirements, resulting in significantly higher incidences of organ dysfunction (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) was the only predictor of intraoperative hypothermia, whereas initial hypothermia 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 have 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.
Bush
H L
HL
Department of Surgery, Cornell University Medical College, New York, New York 10021.
Hydo
L J
LJ
Fischer
E
E
Fantini
G A
GA
Silane
M F
MF
Barie
P S
PS
D018806:APACHE; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007035:Hypothermia / Q000150:complications*; D007431:Intraoperative Complications; D007902:Length of Stay; D008297:Male; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000009:adverse effects / Q000401:mortality