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The following is a summary of “Cardiac arrest secondary to environmental hypothermia: Incidence and outcomes in an urban emergency department in the Upper Midwestern United States,” published in the March 2025 issue of American Journal of Emergency Medicine by Rischall et al. 

Researchers conducted a retrospective study on the incidence and outcomes of hypothermic cardiac arrest (HCA) in an urban setting, including a subgroup analysis of individuals with witnessed events in prehospital or emergency department (ED) settings.  

They analyzed consecutive adults with environmental exposure and a core body temperature of ≤ 32^° C. Characteristics of the cohort were described, and the association between initial core temperature and HCA was evaluated.  

The results showed that 171 individuals met eligibility criteria between January 2007 and September 2023 and HCA occurred in 43 (25%), including 6/98 (6%) with moderate hypothermia (28.01–32^° C), 21/55 (38%) with severe hypothermia (24–28^° C), and 16/18 (89%) with profound hypothermia (<24^°C). Each 1^°C decrease in core temperature below 32^°C increased HCA risk by 2.06 times (95% CI 1.66 to 2.69). Among those with HCA, 18/43 (42%) had a witnessed event during prehospital (n = 8) or ED care (n = 10). The overall (OA) HCA survival rate was 53%, with higher survival in those with an initial core temperature <28^° C compared to >28^° C (62% vs 0%). Survival of individuals experiencing their first HCA after ED arrival was similar to those without HCA (90% vs 94%).  

Investigators concluded the patients with severe environmental hypothermia in urban settings, particularly those with witnessed cardiac arrest, exhibited potential for favorable outcomes when treated in the ED. 

Source: sciencedirect.com/science/article/abs/pii/S0735675724007058