Prognosis of Accidental Hypothermia in the Urban Setting

Abstract

Our goal was to study the outcome and factors affecting outcome in patients with accidental hypothermia in the urban setting. A retrospective cohort study was done on patients admitted to the emergency department with accidental hypothermia (core temperature less than 35°C) from 1991 to 1998. Patients received general intensive care (fluid replacement, mechanical ventilation, cardiopulmonary resuscitation) and were rewarmed actively by intravenous application of warmed fluids, warmed air, pleural lavage, or cardiopulmonary bypass as indicated. Rewarming was successful in 76 of 80 patients (95%) and hospital mortality was 34%. Survivors differed significantly from nonsurvivors with respect to demographic data (indoor finding, homelessness, alcohol abuse, chronic psychiatric disorder, presumed acute alcohol or drug intoxication), findings on admission [severity of hypothermia, systolic blood pressure, heart rate, multiple organ failure (MOF) score, hypothermia outcome score (HOS), BUN, creatinine, CPK, bilirubin, AST, platelet count], but not with respect to therapeutic modalities (mechanical ventilation, volume replacement, pleural lavage, mechanical ventilation, vasopressors, cardiopulmonary bypass). Rewarming time in nonsurvivors, however, was significantly longer. In logistic regression analysis only indoor occurrence, BUN, and platelet count proved to be independent predictors of in-hospital mortality. Survival of patients found outdoors was significantly higher than that of patients found indoors (p < 0.0001). Our study demonstrates that although rewarming and resuscitation are highly effective, accidental urban hypothermia is a condition with a significant in-hospital mortality. There were only a few independent indicators of unfavorable outcome, of which indoor occurrence was by far the most important. Therefore indoor occurrence of hypothermia has to be acknowledged as a risk factor of poor outcome in accidental urban hypothermia.