MARCH Module 05 of 05
H — Hypothermia & Head Injury
Two separate lessons that share a letter. Hypothermia is one arm of the Lethal Triad — a cold casualty clots poorly, so every prior intervention works worse. Head injury is a monitoring problem that starts the moment consciousness changes. One you prevent; one you watch.
The Physiology
Why H Closes The Loop
H does not kill as fast as the earlier letters — it makes every earlier problem worse, and the head problem it watches for announces itself through behavior.
Cold Casualties Clot Poorly
Hypothermia impairs coagulation directly. The tourniquet you applied at M works against a colder, thinner-clotting casualty. Prevention protects everything you already did.
No Cold Weather Required
Shock impairs thermoregulation. Exposure, wet clothing, ground conduction, and wind do the rest — at any ambient temperature. Miami is not a hypothermia-prevention strategy.
Behavior Is The Monitor
A brain injury is tracked through mental status: confusion, vomiting, seizures, inability to follow commands. Your repeated checks are the diagnostic equipment.
Confusion Has Many Causes
Altered mental status is not automatically a head injury — it may be shock, hypoxia, or drugs. Confusion is a red flag for the whole MARCH loop, not just H.
H₁ Hypothermia — Prevent The Third Kill
A shocked casualty may be exposed, may be wet, is often lying on a conductive surface, may receive cold fluids, and has impaired thermoregulation.
C-TECC guidance emphasizes removing wet outer garments, reducing heat loss to the ground, covering the casualty, and keeping them dry.
The heat-loss order
Ground → Wet → Wind → Exposure. Insulate underneath them, not just on top.
- Ground — the casualty loses heat fastest into the surface beneath them. Insulation under the body comes before the blanket on top.
- Wet — wet clothing wicks heat away continuously. Remove and replace when possible.
- Wind — moving air strips the warm layer next to the skin. Shield the casualty.
- Exposure — an uncovered casualty radiates heat from every exposed surface. Cover head to toe.
The blanket everyone remembers to bring does less good than the insulation nobody brings under the casualty.
H₂ Head Injury — Watch The Brain Through Behavior
Think brain injury when you see
- Loss of consciousness — any period, at any point.
- Confusion or repeating questions.
- Inability to follow simple commands.
- Repeated vomiting.
- Seizure activity.
- Progressive deterioration over minutes to hours.
- Abnormal behavior or personality change after trauma.
- Significant head mechanism — even with a normal-acting casualty.
Altered mental status in trauma is not automatically a head injury. It may also represent shock, hypoxia, drugs, or another cause. Treat confusion as a whole-MARCH red flag.
What monitoring looks like
- Check responsiveness and orientation on every loop cycle — and record the times.
- Any decline between checks is the signal. The trend is the diagnosis.
- Protect the spine and airway together in any suspected head injury with significant mechanism.
Don't — The Failure Patterns
- Leaving the casualty directly on concrete, asphalt, or ground — the fastest heat-loss route.
- Leaving them wet, uncovered, or exposed to wind "because it's warm out."
- Assuming a normal-acting casualty with a major head mechanism is fine — brain injuries evolve.
- Missing changing mental status because checks were made once, not repeatedly.
- Blaming every behavior change on the head — and missing shock or hypoxia hiding behind it.
What This Looks Like At Your Level
Switch roles to compare scope
Civilian / Prepared Citizen
Insulate underneath, remove wet clothing, cover head to toe, and monitor mental status continuously. Any decline — or any vomiting, seizure, or confusion — means upgrade the emergency response.
Insulate underneath · Remove wet clothing · Cover · Monitor mental status continuously
Law Enforcement / First Responder
Same, plus casualty packaging for extraction and repeated mental-status checks en route — a downgrade officer or occupant needs warmth under them and a brain being watched.
Same + casualty packaging · Repeated mental-status checks en route
Medic / EMS / Clinician
TBI management per current guidelines — the 2026 TCCC update substantially changed moderate/severe TBI management, including oxygenation and perfusion targets — plus temperature management and destination triage.
TBI management per current guidelines · Oxygenation & perfusion targets · Temperature management · Destination triage
Module Self-Check
Test Your H Knowledge
1. It's 90°F in Miami. Can your trauma casualty become hypothermic?
2. You have one blanket and one casualty on cold pavement. Where does the blanket go?
3. A casualty becomes confused 20 minutes after a crash. Is it automatically a head injury?
4. Why does hypothermia threaten everything you did at M?
5. What does "monitoring for head injury" actually mean in the field?
Equipment
Build Your H Capability
Hypothermia prevention and casualty-monitoring gear, live from the store's head/hypothermia catalog.
H.E.A.T.™ (Hypothermia Emergency Assess and Transport) Set
Mylar Emergency Space Blanket
QinFlow Warrior EXTREME Blood & Fluid Warmer Set
Blizzard IFAK Blanket
You Finished The Sequence
Revisit The Modules — Then Reassess
TCCC content reviewed against CoTCCC Guidelines — 1 May 2026 · Civilian / LE content reviewed against current C-TECC guidance
Guidelines evolve. Agency protocols and scope of practice control. Educational alignment — not a certification.