What is the management approach for a patient with hypothermia?

Hypothermia Management

Immediately initiate active rewarming measures for all hypothermic patients (core temperature <35°C) to achieve normothermia, as hypothermia independently increases mortality, bleeding risk, and coagulopathy. 1, 2

Initial Stabilization and Heat Loss Prevention

Remove wet clothing immediately and move the patient to a warm environment to prevent further heat loss. 2, 3 Cover with dry insulating layers, shield from wind, insulate from the ground, and cover the head and neck. 2 These simple measures are critical first steps regardless of hypothermia severity.

Temperature Measurement

Use esophageal or oral probes for accurate core temperature monitoring when pulmonary artery catheters are not warranted. 2 Tympanic infrared probes serve as acceptable alternatives when oral measurement is not feasible. 2 Avoid axillary measurements as they consistently read 1.5-1.9°C below actual core temperature, leading to inaccurate treatment decisions. 2

Monitor core temperature every 5-15 minutes depending on severity. 2, 3

Treatment Algorithm Based on Severity

Mild Hypothermia (32-35°C)

• Allow passive rewarming with blankets and increase environmental temperature 2
• Provide high-calorie foods or warm drinks if the patient is alert 2
• Monitor for signs of deterioration 2
• Active external rewarming with forced-air warming blankets is recommended even for mild cases to achieve rewarming rates of approximately 2.4°C/hour compared to 1.4°C/hour with passive blankets alone 2

Moderate Hypothermia (28-32°C)

• Continue all measures for mild hypothermia 2
• Apply forced-air warming blankets (e.g., Bair Hugger) as the primary active rewarming method 2, 3, 4
• Administer warmed intravenous fluids (40-45°C isotonic crystalloid at volumes of 500 mL to 30 mL/kg) 4
• Provide humidified, warmed oxygen 2, 3, 4
• Do not rely on passive rewarming alone at 33°C or below—active measures are required 2

Severe Hypothermia (<28°C)

• Continue all measures for moderate hypothermia 2, 3
• Activate the emergency response system 2
• Handle the patient gently throughout to avoid triggering ventricular fibrillation 3, 5
• Consider active core rewarming methods including body cavity lavage or extracorporeal rewarming (ECMO) 2, 6, 5
• Transfer patients with temperature <30°C (or <32°C in elderly/comorbid patients), ventricular dysrhythmias, systolic blood pressure <90 mmHg, or cardiac arrest directly to an ECLS center 5

Rewarming Targets

Target a minimum core temperature of 36°C before considering the patient stable. 2, 3, 4 Cease rewarming at 37°C, as higher temperatures are associated with poor outcomes. 2, 3, 4 This is a critical threshold that must be respected.

Monitoring for Complications

Continuously monitor for:

• Cardiac arrhythmias, particularly bradycardia and ventricular fibrillation 2, 3, 4
• Coagulopathy (each 1°C drop in temperature causes a 10% drop in coagulation factor function) 1
• Rewarming shock 2, 4
• Electrolyte abnormalities and hyperglycemia 2, 4
• Burns from improper use of active external rewarming devices 2

Critical Pitfalls to Avoid

Do not use cold IV fluid boluses for treating accidental hypothermia—this is only indicated for therapeutic hypothermia. 2 All intravenous fluids must be reliably warmed before infusion. 7

Do not assume coagulopathy is absent based on standard laboratory tests run at 37°C—body temperatures below 34°C compromise blood coagulation, but this is only observed when coagulation tests are performed at the patient's actual low temperature. 1

Special Consideration: Traumatic Brain Injury

In trauma patients without TBI, hypothermia must be aggressively corrected as it represents an independent risk factor for bleeding and death. 1 However, for patients with isolated TBI after hemorrhage has been controlled, prolonged hypothermia at 33-35°C for ≥48 hours may be considered, as long-term cooling (>48 hours) shows mortality benefit and improved neurologic outcomes compared to short-term cooling (≤48 hours). 1 Selective brain cooling is more effective than systemic hypothermia for controlling intracranial pressure. 1

Cardiac Arrest Management

If a hypothermic patient arrests, perform continuous CPR. 5 Use mechanical CPR devices for prolonged rescue if available. 5 In severely hypothermic patients in cardiac arrest, if continuous or mechanical CPR is not possible, use intermittent CPR. 5 Hypothermic patients have higher chances of survival and good neurological outcome compared to normothermic patients for witnessed, unwitnessed, and asystolic cardiac arrest. 5