What is the initial approach to a patient presenting with hypothermia?

From the Guidelines

The initial approach to a patient with hypothermia should prioritize rapid assessment, removal of wet clothing, and careful rewarming while supporting vital functions, with the specific rewarming technique dependent on the severity of hypothermia, as outlined in the 2024 American Heart Association and American Red Cross guidelines for first aid 1.

Initial Assessment and Management

When a patient presents with hypothermia, the first step is to move them to a warm environment and remove any wet clothing to prevent further heat loss. Covering the patient with warm blankets is also crucial. It is essential to assess the patient's airway, breathing, and circulation (ABCs) and monitor their core temperature using a rectal, esophageal, or bladder thermometer.

Rewarming Strategies

• For mild hypothermia (32-35°C), passive external rewarming is often adequate 1.
• For moderate to severe hypothermia (<32°C), active rewarming techniques should be employed, including warm IV fluids (heated to 40-42°C), warm humidified oxygen, and possibly more invasive methods like peritoneal lavage or extracorporeal warming in severe cases 1.
• Handling the patient gently is crucial to avoid triggering arrhythmias, particularly ventricular fibrillation, as the hypothermic heart is irritable.
• Cardiac monitoring is essential, and CPR should be continued until the patient is rewarmed to at least 32°C if they are in cardiac arrest.
• Avoid administering cold fluids or medications that may further lower body temperature.

Considerations for Different Levels of Hypothermia

• Mild hypothermia (32-35°C): Patients may be alert and shivering. Passive rewarming is often sufficient.
• Moderate hypothermia (28-32°C): Patients may have a decreased level of responsiveness. Active rewarming methods should be used in addition to passive rewarming.
• Severe hypothermia (<28°C): Patients are unresponsive and may appear lifeless. Active core rewarming techniques are necessary, and methods like cardiopulmonary bypass may be considered for rapid rewarming.

Evidence-Based Practice

The approach to managing hypothermia is guided by the most recent and highest quality evidence, including the 2024 American Heart Association and American Red Cross guidelines for first aid 1 and previous guidelines from the American Heart Association for cardiopulmonary resuscitation and emergency cardiovascular care 1. These guidelines emphasize the importance of rapid assessment, appropriate rewarming strategies based on the severity of hypothermia, and supportive care to prevent complications and improve outcomes.

From the Research

Initial Approach to Hypothermia

The initial approach to a patient presenting with hypothermia involves several key steps:

• Assessing the patient's core body temperature and overall clinical condition 2, 3
• Preventing further heat loss by removing wet garments and insulating the patient 2, 3
• Providing warm humidified air/oxygen to help stabilize core temperature 2
• Monitoring cardiac rhythm and core temperature in the prehospital setting, if possible 2
• Continuing CPR during transport if the patient is not breathing or is pulseless 2

Rewarming Methods

Various rewarming methods can be employed, including:

• Passive insulation with a vapor barrier 3
• Active external rewarming using chemical, electrical, or charcoal-burning heat packs, heated blankets, or forced air warming 3
• Active internal rewarming using heated humidified oxygen, centrally administered warm IV fluids, and peritoneal dialysis or extracorporeal rewarming 2, 4
• Endovascular catheters as an alternative for rapid and controlled rewarming 4
• Hemodialysis as a treatment option for severe accidental hypothermia, which can correct associated acidosis and electrolyte abnormalities 5

Important Considerations

• Delays in rewarming and slower rates of rewarming are associated with increased mortality 5
• Arrhythmias are a common cause of mortality in patients with severe accidental hypothermia, and electrolyte abnormalities such as hyperkalemia and hypocalcemia can contribute to this risk 5
• Postresuscitation complications, including pneumonia, pulmonary edema, cardiac arrhythmias, myoglobinuria, disseminated intravascular thrombosis, and seizures, should be monitored 2