What is the appropriate workup for hypothermia?

From the Guidelines

The workup for hypothermia should begin with rapid assessment and stabilization while simultaneously determining the severity based on core temperature, with the most recent guidelines from 2024 suggesting a tailored approach to rewarming based on the level of hypothermia 1. The initial evaluation should include core temperature measurement using a rectal, esophageal, or bladder thermometer as peripheral measurements are unreliable.

• Laboratory tests should include complete blood count, comprehensive metabolic panel, coagulation studies, arterial blood gas, and toxicology screening.
• An ECG should be obtained to assess for J waves (Osborn waves) and arrhythmias.
• Chest X-ray can identify aspiration or pulmonary edema. For moderate to severe cases, continuous cardiac monitoring is essential as rewarming can precipitate arrhythmias.
• Active internal rewarming methods include warm IV fluids (42°C), heated humidified oxygen, peritoneal lavage with warm fluids, or extracorporeal blood rewarming in severe cases. It is crucial to avoid aggressive external rewarming of extremities before core rewarming to prevent "rewarming shock" from peripheral vasodilation, as emphasized in the 2024 guidelines 1. Underlying causes such as sepsis, endocrine disorders, or drug intoxication should be identified and treated.
• Patients with severe hypothermia may appear clinically dead but should receive continued resuscitation efforts until core temperature reaches at least 32°C, following the principle that "no one is dead until warm and dead" 1. The 2024 American Heart Association and American Red Cross guidelines for first aid provide a comprehensive approach to the management of hypothermia, highlighting the importance of prompt recognition and treatment to improve outcomes 1.

From the Research

Diagnosis and Treatment of Hypothermia

• Hypothermia can be caused by exposure to a cold environment, toxin exposure, metabolic derangements, infections, and dysfunction of the central nervous and endocrine systems 2
• The clinical presentation of hypothermia is grouped into three categories: mild, moderate, and severe 2
• Management of hypothermia depends on the degree of hypothermia present, with treatment modalities ranging from noninvasive to active core rewarming 2, 3

Rewarming Modalities

• Rewarming modalities include passive external, active external, active core, and extracorporeal rewarming 3
• The choice of rewarming modality should be based on the patient's condition, hemodynamic stability, and available resources 3
• Active intravascular rewarming has been shown to be a practical and automated technique for the treatment of hypothermia in trauma patients 4
• Active core rewarming via an indwelling peritoneal dialysis catheter has been used successfully in the management of severe accidental hypothermia 5

Considerations for Rewarming

• Improper rewarming can lead to further injury, and timely reperfusion is crucial to prevent additional damage 6
• The treatment of severe hypothermia is complex and requires careful monitoring to prevent complications such as arrhythmia or hypotension 5
• Prevention and recognition of atypical presentations are essential to reducing the rates of morbidity and mortality associated with hypothermia 2