Cardiopulmonary bypass resuscitation for accidental hypothermia

Many victims of accidental hypothermia have been successfully resuscitated with cardiopulmonary bypass, but questions remain regarding treatment indications and efficacy. To assess the role of cardiopulmonary bypass in resuscitation from hypothermia, a collective literature review was performed. Data on 68 hypothermic patients resuscitated with cardiopulmonary bypass were analyzed. Impairment from alcohol, drug abuse, or mental illness was the most common predisposing factor for accidental hypothermia. Mean initial core temperature was 21 degrees C. Sixty-one patients (90%) were in cardiac arrest. Femoral-femoral bypass was used in 72% of patients. Overall survival was 60%. Eighty percent of survivors returned to their previous level of function. Sixty-seven percent of nonsurvivors died because of inability to establish a cardiac rhythm or wean from bypass. Patient age, type of cardiopulmonary bypass (femoral-femoral or atrial-aortic), and initial core temperature were not significant prognostic indicators. There were no survivors among the 6 patients with a core temperature less than 15 degrees C. Patients in cardiac arrest had a higher mortality than patients who were not (p = 0.02). Climbing and avalanche victims had a higher mortality than other hypothermic patients (p = 0.003). The possibility of publication bias must be considered before firm conclusions can be drawn from this collective literature review. Controlled studies comparing the efficacy of cardiopulmonary bypass and alternative warming techniques have not been done. Nevertheless, cardiopulmonary bypass has several advantages over other warming methods for profoundly hypothermic patients. Tissue perfusion and oxygenation are maintained while rapid warming occurs. Cardiopulmonary bypass resuscitation is recommended for hypothermic patients in arrest and for patients with core temperatures lower than 25 degrees C, irrespective of rhythm. Patients in stable condition with temperatures between 25 degrees and 28 degrees C can be treated with cardiopulmonary bypass or conventional warming methods.