What are the Swiss hypothermia stages?

HT I (32-35°C): conscious, shivering; HT II (28-32°C): impaired consciousness, no shivering; HT III (24-28°C): unconscious, vital signs present; HT IV (<24°C): cardiac arrest; HT V: irreversible hypothermic death.

What serum potassium contraindicates ECMO resuscitation in hypothermia?

Serum K+ >12 mmol/L is used in most guidelines as a contraindication to ECPR in hypothermic cardiac arrest; K >12 indicates cell lysis from asphyxia before cooling, suggesting death was not purely hypothermia-induced.

What is the minimum temperature for successful ECPR in hypothermia?

Successful resuscitation has been reported with core temperatures as low as 13.7°C; the principle "not dead until warm and dead" guides aggressive ECPR in young patients without evidence of asphyxia.

What are passive vs active rewarming methods?

Passive: remove wet clothes, insulate; Active external: heating blankets, warm baths (HT I-II); Active internal: warmed IV fluids, warmed humidified O2, bladder irrigation (HT II-III); ECMO/CPB: HT IV (cardiac arrest).

What drug dosing changes occur in hypothermia?

Drug metabolism and cardiac response are severely impaired below 30°C; vasopressors, digoxin, and antiarrhythmics have reduced or paradoxical effects in severe hypothermia; focus on rewarming before pharmacological interventions.

Accidental Hypothermia Severity Classification and Rewarming Protocol

Classifies accidental hypothermia severity (HT I-IV), calculates ECMO/CPB rewarming eligibility based on core temperature, serum potassium, and cardiac arrest status using the Swiss hypothermia score.

Weight

Height

Clinical Guidance

BMI is a screening measure of body size, not a direct measure of body fat. The standard WHO categories are underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30).

BMI can overestimate body fat in athletes with high muscle mass and underestimate it in older adults with low muscle mass. Interpret it alongside waist circumference and clinical context rather than as a standalone diagnosis.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.

How It Works

Classifies accidental hypothermia severity (HT I-IV), calculates ECMO/CPB rewarming eligibility based on core temperature, serum potassium, and cardiac arrest status using the Swiss hypothermia score

Each component has a specific meaning:

Core temperature — The core temperature recorded for the patient or scenario being assessed.
Serum potassium — The serum potassium recorded for the patient or scenario being assessed.
Cardiac arrest status — The cardiac arrest status recorded for the patient or scenario being assessed.

Note: Interpret the hypothermia severity result against the clinical thresholds and context described above.

How to Use

Enter the core temperature, serum potassium, cardiac arrest status for the patient or scenario you are assessing. Classifies accidental hypothermia severity (HT I-IV), calculates ECMO/CPB rewarming eligibility based on core temperature, serum potassium, and cardiac arrest status using the Swiss hypothermia score. Use the hypothermia severity result to inform your clinical assessment.

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