H — Hypothermia / Head Injury

H Hypothermia / Head Injury

Prevent the silent killer — protect the brain

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Hypothermia Prevention

The “silent killer” in trauma — worsens everything

Why It Matters

• Hypothermia impairs clotting → More bleeding
• Part of the lethal triad: Hypothermia + Acidosis + Coagulopathy
• Starts early, progresses insidiously
• Easier to prevent than to treat

Heat Loss Sources

• Blood loss (warm blood leaving body)
• Wet clothing
• Ground contact
• Wind/air exposure
• Cold IV fluids

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Prevention Steps

1. Remove wet clothing

   • Cut away if needed
   • Do this as soon as tactically feasible

2. Insulate from ground

   • Casualty wrap, blanket, poncho, anything
   • Ground steals heat faster than air

3. Cover completely

   • Especially the head (major heat loss)
   • Wrap in casualty blanket/Blizzard bag

4. Protect from wind

   • Shield casualty from wind
   • Cover face loosely if possible

5. Warm fluids (if available)

   • Use fluid warmers for IV
   • Even body-temp fluids are “cold”

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Temperature Effects

Core Temp	Effect
36°C (96.8°F)	Shivering starts
35°C (95°F)	Coagulation impaired
34°C (93.2°F)	Severe coagulopathy
32°C (89.6°F)	Cardiac arrhythmia risk
Below 30°C (86°F)	Loss of consciousness

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Head Injury

Protect the brain from secondary injury

Assessment

AVPU Scale:

• Alert
• Verbal — responds to voice
• Pain — responds to pain only
• Unresponsive

Pupil Check:

• Size (normal, dilated, constricted)
• Equality (both same size?)
• Reactivity (respond to light?)

Unequal pupils = Concern for increased intracranial pressure

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Secondary Brain Injury

You can’t fix primary injury — prevent secondary

Causes of secondary injury:

• Hypoxia (low oxygen) → Maintain airway/breathing
• Hypotension (low BP) → Maintain perfusion
• Hypoglycemia → Not common in acute trauma
• Increased ICP → Positioning, avoid hypoxia/hypotension

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Head Injury Management

1. Maintain airway — Priority
2. Maintain oxygenation — Avoid hypoxia
3. Maintain blood pressure
   • Target SBP ≥90 mmHg
   • No permissive hypotension in head injury
4. Elevate head 30° if spine cleared
5. Avoid jugular compression (tight collars, head position)
6. Document baseline — Critical for next level of care

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Document for Handoff

• Time of injury (if known)
• Mechanism of injury
• Initial AVPU/GCS
• Pupil findings
• Any changes during care
• Loss of consciousness (duration)

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Signs of Deterioration

Watch for:

• Decreasing level of consciousness
• Pupil changes (especially unilateral dilation)
• Posturing (decerebrate or decorticate)
• Seizures
• Vomiting (aspiration risk)

→ Expedite evacuation if deteriorating