Modern hospitals equipped for severe hypothermia management can use ECMO — extracorporeal membrane oxygenation — to circulate the patient’s blood outside the body through a warming device, raising the core temperature directly and much more rapidly than external heating can accomplish.

ECMO also allows the heart to rest while the warming proceeds, eliminating the risk of arrhythmia during the warming phase because the machine is providing the circulation rather than the patient’s own heart.

Patients who arrive in cardiac arrest from severe hypothermia — patients who have no heartbeat at all — can, in facilities equipped for ECMO, be resuscitated after hours of cardiac arrest if the core temperature is sufficiently low and the cardiac arrest is believed to be a product of the hypothermia rather than an underlying cardiac problem.

Cases have been reported of patients with core temperatures as low as 13 degrees Celsius (approximately 55 degrees Fahrenheit) being resuscitated with ECMO after prolonged cardiac arrest.