Heat Stroke: Recognition and Treatment

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Heat StrokeRecognition and Treatment

• Rodney S. Gonzalez, MD
• MAJ, MC, USA

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Rate of Heat StrokeTrainees and Non-Trainees
Source AMSA/DMSS
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Risk Factors

• Age
• Anticholinergic medication
• Other drugs
• Increased body mass index
• Illness/DM/Spinal cord injury
• Skin disease
• Poor acclimation and conditioning
• Uniform (IBA/MOPP Gear)

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Medications
Drug (Class) Proposed Mechanism of Action
Anticholinergics Impair sweating
Antihistamines Impair sweating
Gluthemide Impair sweating
Phenothiazines Impair sweating, (/-) distrurbed hypothalamic temperature regulation
Tricyclic Antidepressants Impair sweating, increased motor activity and heat production
Amphetamines, Cocaine Increase psychomotor activity, activate vascular endothelium
Ergogenic aids Increase heat production
Lithium Nephrogenic diabetes insipidus and water loss
Diuretics Salt depletion and dehydration
Beta-blockers Impair sweating, reduced skin blood flow, reduced blood pressure
Ethanol Diuresis, possible effects on intestinal permeability
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Medications to Consider
Disease Risky Meds Meds to Consider
URI Chlorpheniramine Deconamine Sudafed Nasal Saline Guaifenesin Cepacol Tylenol Motrin
Seasonal and Chronic Allergies Antihistamines Nasal Steroids Nasal cromolyn
Contact Dermatitis Antihistamines Topical steroids
Congestion Sudafed Guaifenesin
MEDICATION MAY INCREASE RISK FOR HEAT
INJURY Profile for 72 hours (light duty)
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Case 1

• 25yo AD male Ranger Student (28Jul08)
• Arrived Ft. Drum, NY three days prior
• Day 0 Fitness Test
• 4 mile mark noted to be fatigue and dizzy
• Individual sought cadre care
• Medic did rectal temp 105.7
• Brought to Aid Station
• AAO x3
• Rectal Temp 106.1

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Case 2

• 23yo AD male Ranger Student (28Jul08)
• Completed Infantry Officer training at Ft.
  Benning,GA
• Day 0 Fitness Test
• 5 mile completed
• Individual noted to be walking aimlessly
• No colapse
• Medic did rectal temp 105.8
• Brought to Aid Station
• Confused did not know name or location
• Rectal Temp 106.4

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Heat stress is cumulative over the days preceding
the injury

• H Heat Category past 2 days
• E Exertion Level past 2 days
• A Acclimatization/Individual risk factors
• T Temperature/Rest overnight
• Cluster of heat injuries on prior 2 days HIGH
  RISK
• Note 40 of heat injuries may occur under
  green flag conditions. This is probably due to
  previous days heat, work load and dehydration.

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Heat Stroke

• No temperature requirement
• However usually (104-106 minimum)
• Skin hot and flushed, usually dry
• May be moist with exertional
• Headache, dizziness
• Nausea, diarrhea
• Visual disturbances
• Confusion, convulsions, coma
• Initially respiratory alkalosis followed by a
  metabolic acidosis

TBMED507, 2003 Bouchama Knochel NEJM 2002
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Acute CNS Manifestations

• Hyperthermia-gt Increased CNS metabolism
• Increased cerebral vasoconstriction
• Cerebellum most affected- Ataxia, Dysarthria,
  Dysmetria
• AMNESIA
• LOC, disorientated, combative

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Prehospital Care

• RAPID cooling is single most important
  intervention
• Rest
• Oral hydration
• ???IV???

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Soldier has suspected heat illness (dizziness,
headache, dry mouth, nausea, weakness, muscle
cramps) Are there? Mental status changes?
OR Vomits 2x or more? OR Unconsciousness gt 1
minute? OR Rectal temperature gt104º F (Medic or
EMT task)?
YES
NO

• TREAT Stop, Cool
• Loosen clothing
• Place Soldier in shade or cool area
• Provide fluids by mouth 1 qt/30 Min min X 2
• Give salty snack

• EVACUATE Stop, Cool, Call
• Place Soldier flat with legs elevated in cool
  area
• Strip clothing
• Apply iced sheets, soak, fan Soldier
• Evaluate Soldier
• Too much water, urine output, vomiting? Give
  salty snack.
• Poor water, urine output? Sip cool electrolyte
  drink. Never force water.
• IF evacuation delayed gt10 min, only one 500 cc IV
  Normal Saline (IV preferably chilled in ice
  water).
• Stop cooling if shivering or rectal temp is 100
  F. (Medic or EMT task)
• Reconfirm core temperature when evacuation
  arrives (EMT or Medic task)

Soldier gets worse or does not improve in 30
minutes?
YES
Evacuate
NO

• Limited indoor duty for remainder of day
• Medical evaluation within 24 hours

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Hyperthermia Management Protocol
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Hyperthermia Management Protocol
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Hyperthermia Management Protocol
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Hyperthermia Management Protocol
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Hyperthermia Management Protocol
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Hyperthermia Management Protocol
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Exertional Heat Stroke

• Laboratory Heat Panel
• BMP, Ca, Mg, PO4, LFTs, CK, LDH, (/-)Uric Acid,
  CBC, PT/PTT, U/A, Umyoglobin
• Admit to Hospital for monitoring
• Follow labs every 4-8 hours
• Heat Stroke Profile upon discharge