Wilderness Medicine | Acute Care and Resuscitation

Hypothermia Field Management Algorithm

See: Flowchart Illustration (View Image)

Initial/Prep/Goals

1. Move to shelter
   • If available
2. Remove
   • Wet garments
   • Restrictive clothing
3. Protect against heat loss and wind chill
   • Blankets and/or insulating equipment
   • Check and treat isolated frostbitten limbs
4. Maintain horizontal position
   • For at least 30 minutes
5. If possible, check electrolyte levels (e.g. potassium)
   • Treat deficiencies to prevent cardiac arrythmias
6. Monitor core temperature and cardiac rhythm
   • If it the field and patient is intubated
     • Esophageal temperature probes may be most reliable
   • Rectal temperatures
     • May lead to further exposure to environment
7. Are Pulse and Breathing Present? ( YES / NO )

Pulse and Breathing Present

1. Management
   • Directed by core body temperature
2. Hypothermia Treatment
   • Mild: Core temperature 32-35°C [89.6-95°F]
     • Passive rewarming
     • Maintain euvolemia; warm oral/IV fluids as tolerated
     • Active external rewarming as necessary
   • Moderate: Core temperature 28-32°C [86-93.2°F]
     • Passive re-warming
     • Active external re-warming of truncal areas only
       • Practice varies (many think this should be done in hospital settings only)
       • Electric or charcoal warming devices, hot water bottles, heating pads
       • Radiant heat sources, circulating air, warming beds and blankets
   • Severe: Core temperature < 28°C [< 82.4°F]
     • Secure airway
     • Active internal re-warming
       • Warm IVF 43°C [109°F]
       • Warm, humid O2 (42-46°C [108-115°F])
       • Consider peritoneal lavage (KCl-free fluid) if surgical capabilities
       • Extracorporeal rewarming
         • Cardiopulmonary bypass
         • Femoral A-V/V-V bypass
         • Hemodialysis
       • Esophageal rewarming tubes
     • Continue active rewarming until
       • Core temperature > 35°C [> 95°F]
       • Return of spontaneous circulation or
       • Resuscitation efforts cease

Pulse and Breathing Absent

1. See Pulseless Arrest Algorithm
2. Start CPR
3. Give ONE shock at max power for core temp < 30°C [< 86°F]
   • Manual biphasic: Device specific
     • Usually 120-200 J
     • If unknown use 200 J
   • AED: Device specific
   • Monophasic: 360 J
4. Resume CPR immediately
   • If mechanical chest compression device available
     • May be helpful to hasten transport from cold environment
5. Attempt, secure, and confirm airway
6. Ventilate with warm, humid O2 at 42-46°C [108-115°F]
7. Use capnography if available
8. Establish IV access
   • Infuse warm normal saline (43°C [109°F])
9. Re-check core temperature

Check Core Temperature

1. Core temperature > 30°C [> 86°F]
   • Continue CPR
   • Give IV medications (ACLS) as indicated
     • Space at longer than standard intervals
       • Until core temp > 35^oC [> 95^oF]
   • Repeat defibrillation for VF/VT as core temperature rises
   • Perform active internal re-warming ASAP
2. Core temperature < 30°C [< 86°F]
   • Continue CPR
   • Withhold IV medications
     • Hypothermic patients poorly metabolize medications
   • Limit to ONE shock at MAX power for VF/pulseless VT
   • Transport to hospital
   • Start active internal re-warming ASAP

Continue Internal Re-Warming Until

1. Core temperature > 35°C [> 95°F]
2. Return of circulation
   1. ROSC may take longer in patients with hypothermia
3. Resuscitative efforts cease

References

1. In: Auerbach PS, Cushing TA, Harris NS; (eds). Auerbach's Wilderness Medicine, 7th ed., Elsevier, 2017; Chapter 7
2. Panchal AR, Bartos JA, et al. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. Oct 20, 2020; 142(16 Suppl 2): S366-S468
3. Duong H, Patel G. Hypothermia. StatPearls [Internet]. Available at: https://www.ncbi.nlm.nih.gov/books/NBK545239/. [Accessed July 2023]
4. Biem J, Koehncke N, Classen D, Dosman J. Out of the cold: management of hypothermia and frostbite. CMAJ. Feb 4, 2003;168(3):305-311
5. Headdon WG, Wilson PM, Dalton HR. The management of accidental hypothermia. BMJ. Jun 10, 2009;338:b2085
6. McCullough L, Arora S. Diagnosis and treatment of hypothermia. Am Fam Physician. Dec 15, 2004;70(12):2325-2332
7. Paal, P., Gordon, L., Strapazzon, G. et al. Accidental hypothermia–an update. Scand J Trauma Resusc Emerg Med 24, 111 (2016). https://doi.org/10.1186/s13049-016-0303-7
8. Paal P, Pasquier M, Darocha T, Lechner R, Kosinski S, Wallner B, Zafren K, Brugger H. Accidental Hypothermia: 2021 Update. International Journal of Environmental Research and Public Health. 2022; 19(1):501.
9. Dow J, Giesbrecht GG, Danzl DF, et al. Wilderness Medical Society clinical practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia: 2019 update. Wilderness Environ Med. 2019;30(4S):S47-69.

Contributor(s)

1. Ho, Nghia, MD
2. Chase, Olivia, DO
3. Christensen, Matthew, MD
4. Portouw, Steven, MD

Updated/Reviewed: March 2024