USMLE Prep - Medical Reference Library

Accidental Hypothermia — Rewarming and Complications

System: Emergency Medicine • Reviewed: Aug 31, 2025 • Step 1Step 2Step 3

Synopsis:

Classify severity by core temperature and mental status; use active external and internal rewarming strategies and anticipate afterdrop and arrhythmias.

Key Points

  • Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
  • Use system-specific risk tools to guide testing and disposition.
  • Order high-yield tests first; escalate imaging when indicated.
  • Start evidence-based initial therapy and reassess frequently.

Algorithm

  1. Primary survey and vitals; IV access and monitors.
  2. Focused history/physical; identify red flags and likely etiologies.
  3. Order system-appropriate labs and imaging (see Investigations).
  4. Initiate guideline-based empiric therapy (see Pharmacology).
  5. Reassess response; arrange consultation and definitive management.

Clinical Synopsis & Reasoning

For Hypothermia Accidental Moderate Severe, frame the differential by acuity and pathophysiology, then align diagnostics to the leading hypotheses. Prioritize stabilization while obtaining high‑yield studies such as CBC/BMP (Baseline labs), CXR/targeted imaging (Common ED complaints), Troponin/EKG (chest pain) (ACS rule-out). Incorporate bedside imaging and targeted labs to define severity and identify complications; synthesize results with clinical trajectory to refine the working diagnosis and disposition needs.


Treatment Strategy & Disposition

Initiate disease‑directed therapy alongside supportive care, titrating to objective response. Pharmacologic options commonly include Analgesics, Antiemetics. Use validated frameworks (e.g., Rewarming Options) to guide escalation and site of care. Address precipitating factors, de‑escalate empiric therapies with data, and arrange follow‑up for monitoring and risk‑factor modification; admit patients with instability, high risk of deterioration, or needs for close monitoring.


Epidemiology / Risk Factors

  • Varies by presentation; age/comorbidities matter

Investigations

TestRole / RationaleTypical FindingsNotes
CBC/BMPBaseline labsAbnormalities
CXR/targeted imagingCommon ED complaintsFindings vary
Troponin/EKG (chest pain)ACS rule-outMI changesUse risk tools

Rewarming Options

MethodUse case
Warmed IV fluids and blanketsMost patients
Warmed humidified oxygenAdjunct
Lavage or extracorporealSevere or arrest

Pharmacology

MedicationMechanismOnsetRole in TherapyLimitations
Benzodiazepine (shivering)GABA-A potentiationMinutesSedation during rewarmingRespiratory depression
Warm IV fluidsSupportiveHoursRewarming

Prognosis / Complications

  • Outcomes tied to emergency and timeliness of care

Patient Education / Counseling

  • Explain red flags and when to seek emergent care.
  • Reinforce medication adherence and follow-up plan.

Notes

Afterdrop can worsen hypotension during rewarming. Treat hypoglycemia and consider thiamine in malnourished patients.


References

  1. Wilderness Medical Society Hypothermia Guidelines — Link
  2. ERC ALS — Hypothermia — Link