Written by Clay Smith
A faster early rewarming rate of 3º per hour, when going from very cold to 33ºC, was associated with improved 28-day survival and favorable neurological outcome.
It’s getting hot in here…
This was a secondary analysis of prospectively collected data (ICE-CRASH study) from 36 Japanese hospitals and included 395 patients with accidental hypothermia (<32ºC). They focused on early rewarming, from ED arrival to 33ºC, and used multiple logistic regression to adjust for hospital, age, GCS, SBP, and ECMO use. Rewarming rate was significantly associated with 28-day survival and favorable neurologic outcomes: OR 1.51 (95%CI 1.10–2.09; p = 0.011) and OR 1.32 (95%CI, 1.06–1.64; p =0.015), respectively.
Below is the money shot. Note how mortality and neurological outcome benefits plateau at ~3ºC/hour. Faster rewarming >3ºC/hour did not seem to help and may even be associated with harm (i.e. don’t cook your patient, ok?).
There were some issues with the study. First, it is retrospective. Next, rewarming procedures were at the treating team’s discretion and varied. Finally, most patients were elderly, found indoors, and were from a homogenous Japanese population.
How will this change my practice?
This study strongly suggests that in the early rewarming phase (going from ice block to 33ºC), faster is better, with an ideal target rate of around 3º per hour. While it would be nice to have a prospective trial of rewarming rates, this seems unlikely, since Big Blanket is not as well funded as Big Pharma. So, this may be the best we get when patients arrive cold.
Source
Association Between Rewarming Rate and Survival and Neurologic Outcome of Accidental Hypothermia. Crit Care Med. 2025 Jul 1;53(7):e1416-e1425. doi: 10.1097/CCM.0000000000006712. Epub 2025 Jun 3. PMID: 40459372.
