Therapeutic hypothermia after cardiac arrest: Unintentional overcooling is common using ice packs and conventional cooling blankets

Abstract

Although therapeutic hypothermia for cardiac arrest survivors has been shown to improve neurologically intact survival, optimal methods to ensure controlled induction and maintenance of cooling are not clearly established. Precise temperature control is important to evaluate because unintentional overcooling below the consensus target range of 32-34 degrees C may place the patient at risk for serious complications. We sought to measure the prevalence of overcooling (1 hr was identified as follows: 20 of 32 patients (63%) reached temperatures of <32 degrees C, 9 of 32 (28%) reached temperatures of <31 degrees C, and 4 of 32 (13%) reached temperatures of <30 degrees C. Of those with overcooling of <32 degrees C, 6 of 20 (30%) survived to hospital discharge, whereas of those without overcooling, 7 of 12 (58%) survived to hospital discharge (p = not significant). The majority of the cases reviewed demonstrated unintentional overcooling below target temperature. Improved mechanisms for temperature control are required to prevent potentially deleterious complications of more profound hypothermia.