Epidemiology, Management, and Outcomes of Accidental Hypothermia: A Multicenter Study of Regional Care.

BACKGROUND: Hypothermia is an uncommon, potentially life-threatening condition. We hypothesized (1) advanced rewarming techniques were more frequent with increased hypothermia severity, (2) active rewarming is increasingly performed with smaller intravascular catheters and decreased cardiopulmonary bypass, and (3) mortality was associated with age, hypothermia severity, and type.

METHODS: Trauma patients with temperatures <35°C at 4 ACS-verified trauma centers in Wisconsin and Minnesota from 2006 to 2016 were reviewed. Statistical analysis included chi-square and Fisher's exact tests. A P value < .05 was considered significant.

RESULTS: 337 patients met inclusion criteria; primary hypothermia was identified in 127 (38%), secondary in 113 (34%), and mixed primary/secondary in 96 (28%) patients. Hypothermia was mild in 69%, moderate in 26%, and severe in 5% of patients. Intravascular rewarming catheter was the most frequent advanced modality (2%), used increasingly since 2014. Advanced techniques were used for primary (12%) vs. secondary (0%) and mixed (5%) ( P = .0002); overall use increased with hypothermia severity but varied by institution. Dysrhythmia, acute kidney injury, and frostbite risk worsened with hypothermia severity ( P < .0001, P = .031, and P < .0001, respectively). Mortality was greatest in patients with mixed hypothermia (39%, P = .0002) and age >65 years (33%, P = .03). Thirty-day mortality rates were similar among severe, moderate, and mild hypothermia ( P = . 44).

CONCLUSION: Advanced rewarming techniques were used more frequently in severe and primary hypothermia but varied among institutions. Advanced rewarming was less common in mixed hypothermia; mortality was highest in this subgroup. Reliance on smaller intravascular catheters for advanced rewarming increased over time. Given inconsistencies in management, implementation of guidelines for hypothermia management appears necessary.