Accidental Hypothermia: 2021 Update.

Peter Paal,Mathieu Pasquier,Ken Zafren,Bernd Wallner,Hermann Brugger,Sylweriusz Kosinski,Tomasz Darocha,Raimund Lechner

doi:10.3390/ijerph19010501

Abstract

Accidental hypothermia is an unintentional drop of core temperature below 35 °C. Annually, thousands die of primary hypothermia and an unknown number die of secondary hypothermia worldwide. Hypothermia can be expected in emergency patients in the prehospital phase. Injured and intoxicated patients cool quickly even in subtropical regions. Preventive measures are important to avoid hypothermia or cooling in ill or injured patients. Diagnosis and assessment of the risk of cardiac arrest are based on clinical signs and core temperature measurement when available. Hypothermic patients with risk factors for imminent cardiac arrest (temperature < 30 °C in young and healthy patients and <32 °C in elderly persons, or patients with multiple comorbidities), ventricular dysrhythmias, or systolic blood pressure < 90 mmHg) and hypothermic patients who are already in cardiac arrest, should be transferred directly to an extracorporeal life support (ECLS) centre. If a hypothermic patient arrests, continuous cardiopulmonary resuscitation (CPR) should be performed. In hypothermic patients, the chances of survival and good neurological outcome are higher than for normothermic patients for witnessed, unwitnessed and asystolic cardiac arrest. Mechanical CPR devices should be used for prolonged rescue, if available. In severely hypothermic patients in cardiac arrest, if continuous or mechanical CPR is not possible, intermittent CPR should be used. Rewarming can be accomplished by passive and active techniques. Most often, passive and active external techniques are used. Only in patients with refractory hypothermia or cardiac arrest are internal rewarming techniques required. ECLS rewarming should be performed with extracorporeal membrane oxygenation (ECMO). A post-resuscitation care bundle should complement treatment.

Highlights

The management of accidental hypothermia has made substantial progress over the last two decades and hypothermic cardiac arrest (CA) patients who often do not survive with traditional rewarming methods have become increasingly salvageable with extracorporeal life support (ECLS) [1,2,3,4,5,6,7,8]
Some pathophysiological mechanisms are similar, accidental hypothermia should neither be compared to induced hypothermia (as used in deep hypothermic circulatory arrest (DHCA) for cardiovascular surgery) nor to therapeutic hypothermia: i) accidental hypothermia happens unexpectedly and is uncontrolled; ii) it is often associated with exposure to cold environments and/or secondary to impaired thermoregulation e.g. alcohol, drug ingestion, trauma, extremes of age or co-morbid illness [10]
Delayed or intermittent cardiopulmonary resuscitation (CPR) may be appropriate in hypothermic arrest when continuous CPR is impossible

Summary

Introduction

The management of accidental hypothermia has made substantial progress over the last two decades and hypothermic CA patients who often do not survive with traditional rewarming methods (e.g. dialysis, pleural lavage) have become increasingly salvageable with extracorporeal life support (ECLS) [1,2,3,4,5,6,7,8]. This paper provides an up-to-date review of the management and outcome of accidental hypothermia patients with and without cardiac arrest. The management of accidental hypothermia has made substantial progress over the last two decades and hypothermic cardiac arrest (CA) patients who often do not survive with traditional rewarming methods (e.g. dialysis, pleural lavage) have become increasingly salvageable with extracorporeal life support (ECLS). ECLS has substantially improved survival and is the treatment of choice in the patient with unstable circulation or CA.

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