Elsevier

Resuscitation

Volume 93, August 2015, Pages 118-123
Resuscitation

Clinical paper
Outcome after severe accidental hypothermia in the French Alps: A 10-year review

https://doi.org/10.1016/j.resuscitation.2015.06.013Get rights and content

Abstract

Objective

To describe the factors associated with outcome after accidental deep hypothermia.

Methods

We conducted a retrospective cohort study on patients with accidental hypothermia (core temperature <28 °C) admitted to a Level I emergency room over a 10-year period.

Results

Forty-eight patients were included with a median temperature of 26 °C (range, 16.3–28 °C) on admission. The etiology of hypothermia was exposure to a cold environment (n = 27), avalanche (n = 13) or immersion in cold water (n = 8). Mean age was 47 ± 22 years, and 58% were males. Thirty-two patients had a cardiac arrest (CA): 15 patients presented unwitnessed cardiac arrest (UCA) and 17 patients presented rescue collapse (RC). Extracorporeal life support (ECLS) was implemented in 21 patients with refractory cardiac arrest and in two patients with hemodynamic instability. Overall mortality was 50%. For cardiac arrest patients, only three out of 15 patients with UCA survived at day 28, whereas eight out of 17 patients with RC survived. The cerebral performance category score was 4 for all the survivors of UCA and 1 [range, 1–2] for survivors of RC. Patients with poor outcome presented more UCA, a lower pH, a higher serum potassium, creatinine, serum sodium or lactate level as well as more severe coagulation disorders.

Conclusion

Cardiac arrest related to rescue collapse was associated with favorable outcome. On-scene rescue collapse should prompt prolonged resuscitation and ECLS rewarming in all CA patients with deep hypothermia. Conversely, unwitnessed cardiac arrest was associated with unfavorable outcome and will likely not benefit from ECLS.

Introduction

Accidental hypothermia is defined as a core body temperature below 35 °C due to imbalance between cold exposure and thermoregulation mechanisms. Accidental hypothermia is associated with significant mortality and morbidity, especially when the core temperature is under 28 °C with an increased risk of cardiac arrest (CA).1, 2, 3, 4, 5 In the United States, 1500 deaths per year are related to hypothermia.6 The protective effect of hypothermia during cardiac arrest has been described, which is partly related to a decrease in metabolic activity combined with the neuroprotective effect of hypothermia.1 Hence, full neurologic recovery has been described despite prolonged resuscitation.7, 8

Since most studies have reported case series with small sample sizes, few predictive factors of mortality have been established.1 Extreme ages of life; association with chronic illness, alcohol consumption, toxicomania, and homelessness have been associated with poor outcome. Death by hypothermia was also found to be more frequent in males.9 High serum potassium has also been proposed as a marker of irreversibility of cardiac arrest after accidental hypothermia.10

The aim of this study was to determine the factors associated with survival in patients with severe hypothermia and/or deep hypothermic cardiac arrest within a 10-year period in a Level I trauma center.

Section snippets

Setting

This study was conducted at Grenoble University Hospital, a Level I trauma center and a tertiary referral teaching hospital with 2235 beds, located in the French Alps, a mountainous area with cold weather during winter. Grenoble's hospital is part of the Northern French Alps Emergency Network and is the reference center for management of severe hypothermia. An extracorporeal life support (ECLS) dedicated team is available 24/7. In our institution ECLS is preferred over cardiopulmonary bypass

Results

One hundred and sixty-four files were identified with a principal or associated diagnosis of hypothermia, of which 48 patients were included in the study (Fig. 2). Thirty-two patients had a cardiac arrest, 15 patients had unwitnessed CA (UCA group) and 17 patients had rescue collapse (RC group). The patients’ characteristics are summarized in Table 1.

Twenty-four patients did not survive at hospital discharge. Only three out of 16 patients with sustained spontaneous circulation throughout

Discussion

This study is the first report of patients with deep accidental hypothermia admitted to a French Level I emergency room. In this study, patients with preserved cardiac activity from the scene to the beginning of hospital rewarming had good neurological outcomes. If cardiac arrest occurred during extrication or initial management, half of our patients survived with a good neurologic outcome. These results argue in favor of prolonged resuscitation efforts in rescue collapses until ECLS

Conclusion

In this 10-year retrospective study, cardiac arrest occurring during extrication or transport of patients with deep hypothermia (rescue collapse) is associated with a good survival rate (50%). In cases of rescue collapse, resuscitation efforts should be pursued even for long transportation times and patients must be oriented toward a center with ECLS rewarming capability. In contrast, a hypothermic unwitnessed cardiac arrest is associated with a poor prognosis, which should be considered to

Conflict of interest statement

The authors declare no conflicts of interest.

Acknowledgments

We thank the emergency physicians, nurses and ambulance crews of the intensive care units and the Grenoble University Hospital emergency department as well as emergency medical services and mountain rescue teams from Isère, Savoie and Haute-Savoie for their help in completing data acquisition for this study.

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    A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2015.06.013.

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