Hypothermia Treatment Calculator

A significantly cooled heart is electrically unstable and can be provoked into ventricular fibrillation by rough movement, aggressive intubation attempts, or vigorous chest compressions performed before the patient is positioned for monitoring. This is why severe and profound hypothermia protocols emphasize minimal, careful handling alongside continuous cardiac monitoring, rather than only focusing on the rewarming rate itself.

Afterdrop is a further drop in core temperature that can occur during rewarming, as cold, poorly circulated blood from the extremities returns to the body's core once peripheral blood vessels dilate. It's a reason rewarming rate isn't simply "faster is better" -- overly aggressive peripheral rewarming can transiently worsen core temperature and precipitate the same cardiac instability the rewarming was meant to prevent.

Risk generally escalates in stages as core temperature falls: atrial fibrillation becomes more likely below roughly 30°C, and ventricular fibrillation susceptibility rises further below roughly 28°C, which is part of why 28°C is commonly used as the cutoff between "moderate" and "severe" hypothermia requiring more aggressive rewarming and continuous cardiac monitoring.

No -- passive rewarming (blankets, warm environment, allowing the body to rewarm itself) is generally considered adequate only for mild hypothermia in patients who are still shivering and hemodynamically stable. Moderate hypothermia typically needs active external rewarming, and severe or profound hypothermia typically needs active internal or even extracorporeal rewarming, because a body that cold usually cannot generate enough of its own heat to recover through insulation alone.