What is the best treatment approach for a patient with hypothermia, considering their age, medical history, and environmental exposure?

Hypothermia Treatment

All hypothermic patients should be immediately moved to a warm environment, have wet clothing removed, and receive passive rewarming with dry blankets, with the addition of active rewarming methods based on severity—mild cases (32-35°C) require passive measures alone, moderate cases (28-32°C) need active external rewarming with forced-air warming blankets, and severe cases (<28°C) require active core rewarming with warmed IV fluids while handling the patient gently to avoid triggering fatal arrhythmias. 1

Initial Assessment and Universal Interventions

Treatment decisions must be guided by clinical signs and symptoms since core temperature measurement is often unavailable in first aid settings. 1 However, when available, always base diagnosis and treatment on measured core temperature rather than clinical presentation alone, as patients can appear deceptively stable despite severe hypothermia. 2

Immediately implement these measures for all hypothermic patients: 1

• Remove all wet clothing to prevent further heat loss
• Move patient from cold environment to warm shelter
• Insulate from ground contact
• Cover head and neck (major heat loss areas)
• Shield from wind using plastic or foil layer plus dry insulating layer
• Apply at least two dry blankets 3

Severity-Based Treatment Algorithm

Cold Stress (35-37°C): Alert, Possibly Shivering

Passive rewarming is adequate for healthy individuals at this stage. 1

• Remove from cold environment and protect from further heat loss
• No active rewarming typically needed 1

Mild Hypothermia (32-35°C): Altered Responsiveness, Shivering Present

Combine passive and active rewarming methods. 1

• Continue all universal interventions above
• Provide high-calorie foods or warm drinks if patient is alert and can safely swallow 1
• Protect from falls due to altered coordination 1
• Seek additional medical care 1

Moderate Hypothermia (28-32°C): Decreased Responsiveness, Shivering May Be Absent

This is a medical emergency requiring immediate activation of emergency services and aggressive active external rewarming. 1

• Activate emergency response system immediately 1
• Handle patient gently to avoid triggering arrhythmias 1
• Apply forced-air warming blankets, which increase rewarming rates to approximately 2.4°C/hour compared to 1.4°C/hour with passive blankets alone 3, 4
• Administer warmed intravenous fluids 4
• Provide humidified, warmed oxygen 4
• If patient cannot be moved and is wearing damp (not saturated) polyester fleece, initiate active rewarming through the damp clothing using the hypothermia wrap technique with chemical heat blankets, plastic/foil layers, and insulative blankets 1

Severe/Profound Hypothermia (<28°C): Unresponsive, High Risk for Cardiac Arrest

Requires active core rewarming in addition to all external measures. 1, 3

• Continue all measures for moderate hypothermia
• Consider peritoneal lavage with warmed fluids 3, 5
• Handle extremely gently—any rough movement can trigger ventricular fibrillation 3
• If cardiac arrest occurs, begin CPR immediately and attempt defibrillation if indicated 3
• Consider vasopressors (epinephrine or vasopressin) for cardiac arrest 3
• Transfer directly to ECLS (extracorporeal life support) center if available 6

Critical Rewarming Targets and Monitoring

Target a minimum core temperature of 36°C before considering the patient stable, but cease rewarming at 37°C—temperatures above this are associated with poor outcomes and increased mortality. 3, 5

Expected rewarming rates: 3

• Conservative methods: approximately 1.09°C per hour
• Forced-air warming: up to 2.4°C per hour
• With shivering present: up to 3.6°C per hour

Monitor core temperature every 5-15 minutes depending on severity using: 3, 4

• Oral or esophageal probes (preferred for accuracy)
• Tympanic infrared probes (acceptable alternative)
• Avoid axillary measurements—they read 1.5-1.9°C below actual core temperature 4

Safety Precautions During Rewarming

When using any rewarming device: 1

• Follow manufacturer's instructions precisely
• Place insulation between heat source and skin
• Frequently monitor for burns and pressure injuries

Do not use body-to-body rewarming—it is not beneficial compared to chemical heat packs or forced-air systems. 1

Continuous Monitoring for Complications

Watch for these potentially life-threatening complications during rewarming: 3, 4

• Cardiac arrhythmias (particularly bradycardia and ventricular fibrillation)
• Coagulopathy
• Electrolyte abnormalities
• Hyperglycemia (especially in diabetic patients)
• Rebound hyperthermia
• Rewarming shock and hemodynamic instability

Critical Pitfalls to Avoid

Never administer cold IV fluid boluses for accidental hypothermia—this is only indicated for therapeutic hypothermia in specific protocols. 4

Do not rapidly rewarm post-cardiac arrest patients—maintain temperature between 32-36°C in this population. 5

Do not overlook hypothermia during initial resuscitation—prevention is easier than treatment once significant heat loss has occurred. 5

Each 1°C decrease in temperature causes a 10% reduction in coagulation factor function, making early intervention critical in trauma and surgical bleeding scenarios. 5

High-Risk Populations

The very young, elderly, and those with impaired temperature perception or communication ability are at increased risk. 1 In the United States, hypothermia causes approximately 1,300 deaths annually, with highest rates among men, the elderly, and rural populations. 1