Table of contents
Accidental hypothermia
What's new
Updated 2024 WMS guidelines for the management of avalanche victims.
Background
Overview
Definition
Accidental hypothermia is defined as an unintentional decline in the core body temperature to < 35 °C due to environmental exposure.
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Pathophysiology
The pathophysiology of accidental hypothermia involves a combination of heat loss and impaired thermoregulation. Heat loss can occur through radiation, conduction, convection, and evaporation. Impaired thermoregulation can result from factors such as sepsis, which can disrupt the body's normal temperature control mechanisms.
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Epidemiology
In the US, accidental hypothermia is responsible for at least 1,500 deaths each year. The incidence of accidental hypothermia in the Netherlands is estimated at 1.1 per 100,000 person-years.
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Disease course
Clinical manifestations of accidental hypothermia can vary depending on the severity. Mild hypothermia may present with shivering and altered mental status. As the condition worsens, patients may exhibit detectable vital signs even with core temperatures < 24 °C. Severe hypothermia can lead to cardiac arrhythmias, hypoventilation, and in extreme cases, cardiac arrest.
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Prognosis and risk of recurrence
The overall mortality rate of accidental hypothermia is significant. In a study conducted in Japan, the overall proportion of cases resulting in in-hospital death was 24.4%.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of accidental hypothermia are prepared by our editorial team based on guidelines from the Wilderness Medical Society (WMS 2024,2019) and the American Heart Association (AHA 2020)....
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Diagnostic investigations
Field assessment: as per WMS 2019 guidelines, Classify hypothermia as mild, moderate, severe and profound on the bases of clinical observations, recognizing that:
shivering can occur below 32 °C, usually with altered mental status
patients can have detectable vital signs with core temperatures below 24 °C
core temperature can overlap between classification categories.
B
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Core temperature measurement
Respiratory support
Airway management: as per WMS 2024 guidelines, Initiate standard resuscitation and Advanced Life Support (including volume resuscitation and endotracheal intubation or placement of an extraglottic airway with normocapnic ventilation if indicated) in avalanche victims with a burial duration ≤ 60 minutes or core temperature ≥ 30 °C.
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Ventilation
Medical management
Fluid resuscitation: as per WMS 2024 guidelines, Initiate volume resuscitation as part of Advanced Life Support in avalanche victims with a burial duration ≤ 60 minutes or core temperature ≥ 30 °C.
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Vasopressors
Glucose and insulin
Nonpharmacologic interventions
Out-of-hospital management, safety of the rescuer: as per WMS 2019 guidelines, Ensure that the scene is secure and safe to enter and make an evaluation before the decision to rescue or resuscitate a patient.
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Out-of-hospital management (patient handling)
Out-of-hospital management (protection from cold)
Out-of-hospital management (passive rewarming)
Out-of-hospital management (active rewarming)
Out-of-hospital management (rewarming during transport)
Out-of-hospital management (non-hypothermic cold-stressed patients)
Out-of-hospital management (patients with severe trauma)
Transportation