Virginia Tech Carilion Wellness Medicine Journal Club

Topic: Guidelines on Hypothermia

Introductions

Justin Gardner: Host, plans to go through WMS guidelines on hypothermia, related articles, and a case study.
Dan: Emergency medicine intern, presenting WMS guidelines for out-of-hospital treatment of accidental hypothermia.

Key Concepts

Mechanisms of Heat Transfer

Convection, Conduction, Radiation, Evaporation
Normal human core body temperature: 37°C
Hypothermia: Core body temperature < 35°C

Physiological Mechanisms Against Hypothermia

Heat Retention: Vasoconstriction
Heat Production: Shivering
Behavioral Adaptations: Thermogenesis through exercise, seeking shelter, insulated clothing

WMS Guidelines Update (2019)

Classification: Mild, Moderate, Severe, Profound based on temperature and clinical signs
Alternative Systems: SWIS, American Heart Association Guidelines
Field Assessment: Focus on physiologic changes, not defibrillation outcomes

Measuring Core Temperature

Preferred Methods: Esophageal probe (secured airway), Epitampanic thermometer
Recommendations Against: Rectal measurement unless in warm environment, infrared tympanic and oral thermometers that cannot read below 35°C

Out-of-Hospital Treatment

Scene Safety: Ensure before rescue
Core Temperature After Drop: Continue to drop post-rescue due to peripheral cold body parts
Circum-Rescue Collapse: Syncope upon rescue
Patient Handling: Horizontal, gentle, minimal movement
Insulation: Use blankets, vapor barriers, remove wet clothes

Rewarming Methods

Shivering: Effective for mild hypothermia
Active Heat Sources: HPMK, body-to-body rewarming, external heat to specific body parts
Fluids: Warmed, high-carbohydrate liquids and food

Resuscitation

CPR: Immediate whenever possible, consider mechanical devices for prolonged cases
Defibrillation: Limited to one shock below 30°C
Airway Management: Intubation recommended despite risks of VFib

Transport and Triage

Rewarming: Continue until hospital
Facility Choices: Based on severity and hypothermia degree
Biochemical Markers: Potassium levels as a survival indicator

Article 1: Wrap Systems for Hypothermia

Comparison of 5 hypothermia wrap systems
User assembled systems showed comparable results to commercial systems
Small sample size, further studies needed

Article 2: HOPE Score

Use of HOPE score vs potassium levels in predicting survival
Retrospective study, shows promise for better survival predictions
Limitations include small sample size and retrospective design

Case Study: Hypothermia in the Field

Scenario

45-year-old male, found unresponsive after missing overnight in cold conditions
Severe hypothermia (core temp 25°C)

Actions Taken

Scene Safety: Confirmed
Initial Assessment: Airway clear, bradycardic pulse, cold to touch
Packaging: Burrito wrap using patient’s and team’s gear

Transport

EMS Role: Continued passive rewarming, prepared for transport
Arrival at Hospital: Airway management, consideration for ECMO, invasive rewarming techniques

Hospital Treatment

Airway Management: Intubation, warming circuit
Invasive Warming: Chest tubes for lavage

Outcome

Successful rewarming and discharge with good neurological recovery

This study session provided comprehensive coverage of hypothermia, focusing on the guidelines, treatment options, and practical application through a case study. Emphasized the importance of warming techniques, classification systems, and understanding physiological processes involved in hypothermia management.

Understanding Hypothermia and Treatment Guidelines