Swiss hypothermia staging + rewarming algorithm
Swiss staging of accidental hypothermia (Durrer 2003) with the matched rewarming pathway.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Core temperature
- 30 C
- Patient state
- Impaired consciousness, breathing (HT II)
Result: HT II at 30 C per Durrer 2003: active external + minimally invasive (forced-air warming + warm IV).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- HT I
- Alert and shivering. Passive external rewarming.
- HT II
- Impaired consciousness, breathing. Active external + minimally invasive; avoid jostling.
- HT III
- Unconscious, vital signs present. Active internal; consider ECMO / CPB if unstable.
- HT IV
- Cardiac arrest. ECPR is first-line per ERC 2021 §4.7 unless K+ > 12 or lethal-injury / chest-non-compressible flag.
What you enter
- Core temperature
- Patient state (HT I-IV)
- ECPR exclusion (lethal injury / non-compressible chest / known asystole before cooling)
- Serum potassium (optional)
How this is calculated
Durrer B, Brugger H, Syme D. ICAR-MEDCOM hypothermia staging. High Alt Med Biol. 2003;4(1):99-103. Lott C, et al. ERC 2021 Guidelines: cardiac arrest in special circumstances. Resuscitation. 2021;161:152-219 (§4 hypothermia, including K+ > 12 ECPR cut-off). Read the sources: Durrer 2003 ↗, ERC 2021 ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.