Hyperthermia/Heat Exposure

Table of Contents

Aliases

Hyperthermia, heat cramps, heat exhaustion, heat syncope, heat edema, heat stroke

Definitions

  1. Heat Cramps: are minor muscle cramps usually in the legs and abdominal wall. Patient temperature is normal
  2. Heat Exhaustion: has both salt and water depletion usually of a gradual onset. As it progresses tachycardia, hypotension, elevated temperature, and very painful cramps occur. Symptoms of headache, nausea and vomiting occur. Heat exhaustion can progress to heat stroke
  3. Heat Stroke: occurs when the cooling mechanism of the body (sweating) ceases due to temperature overload and/or electrolyte imbalances. Patient temperature is usually 104° When no thermometer is available, it is distinguished from heat exhaustion by altered level of consciousness
  4. Heat Syncope: is a transient loss of consciousness with spontaneous return to normal mentation attributable to heat exposure
  5. Heat Edema: is dependent extremity swelling caused by interstitial fluid pooling

Patient Care Goals

  1. Cooling and rehydration
  2. Mitigate high risk for decompensation
  3. Mitigate high risk for agitation and uncooperative behavior

Patient Presentation

Inclusion Criteria

  1. Heat cramps
  2. Heat exhaustion
  3. Heat stroke
  4. Heat syncope
  5. Heat edema
  6. Stimulant drug abuse
  7. Excited delirium [see Agitated or Violent Patient/Behavioral Emergency guideline]

Exclusion Criteria

  1. Fever from infectious or inflammatory conditions
  2. Malignant hyperthermia
  3. Serotonin syndrome
  4. Neuroleptic malignant syndrome

Patient Management

Assessment

  1. Patient Assessment:
    1. Age
    2. Oral intake
    3. Medications
    4. Alcohol
    5. Illicit drugs
    6. Overdose
    7. Withdrawal risk
  2. Environmental Assessment:
    1. Ambient temperature and humidity
    2. Exertion level
    3. Length of time at risk
    4. Attire (clothing worn)
    5. Confined space
      1. Pediatric Considerations: Children left in cars who show signs of altered mental status and elevated body temperature should be presumed to have hyperthermia
  3. Associated Symptoms:
    1. Cramps
    2. Headache
    3. Orthostatic symptoms
    4. Nausea
    5. Weakness
    6. Mental status changes, including
      1. Confusion
      2. Coma
      3. Seizures
      4. Psychosis
  4. Vital signs:
    1. Temperature – usually 104°F or greater (if thermometer available)
    2. Skin:
      1. Flushed and hot
      2. Dry or sweaty
      3. Signs of first or second degree burns from sun exposure
    3. Other signs of poor perfusion/shock

Treatment and Interventions

  1. Move victim to a cool area and shield from the sun or any external heat source
  2. Remove as much clothing as is practical and loosen any restrictive garments
  3. If alert and oriented, give small sips of cool liquids
  4. If altered mental status, check blood glucose level
  5. Manage airway as indicated.
  6. Place on cardiac monitor and record ongoing vital signs and level of consciousness
  7. If temperature is greater than 104°F (40°C) or if altered mental status is present, begin active cooling by:
    1. Ice bath immersion provides the most rapid cooling mechanism but may not be available to EMS – If shivering occurs during cooling:
      1. Contact medical control for antishivering medications
    2. Continually misting the exposed skin with tepid water while fanning the victim (most effective)
    3. Truncal ice packs may be used, but are less effective than evaporation
    4. DO NOT apply wet cloths or wet clothing, as they may trap heat and prevent evaporative cooling
  8. Cooling efforts should continue until the patient’s temperature is less than 102.2°F (39°C), if available, and the patient demonstrates improvement in mental status
  9. Establish IV access for patients suffering from heat stroke – give room temperature or cool fluids at 20 mL/kg boluses, max of 2L
  10. Monitor for arrhythmia and cardiovascular collapse [see Cardiovascular section guidelines]
  11. Treat seizures, per the Seizures guideline
  12. All patients suffering from life threatening heat illness (including heat stroke) should be transported to the hospital

Notes – Hyperthermia/Heat Exposure