Cold Weather Considerations

Cold Weather Changes Everything

Cold environments don’t just add hypothermia risk — they fundamentally alter how you execute every step of MARCH. Your gear behaves differently. Your casualty’s physiology changes. Your own dexterity degrades. Understanding these factors before you’re in the situation is critical.

---

1. Hypothermia — The Silent Threat

Hypothermia is always a concern in trauma, but in cold environments it becomes the dominant threat multiplier.

The Danger

• A “stable” patient can crash without warning as core temp drops
• Hypothermia is insidious — by the time you notice signs, it’s advanced
• The lethal triad (hypothermia, acidosis, coagulopathy) accelerates in cold
• Rewarming in the field is extremely difficult

Cold Weather Actions

• Heat/Blizzard Blanket — Deploy immediately, not as an afterthought
• Insulate underneath — Ground contact steals heat faster than air
• Limit exposure — Every second of skin exposed to cold wind matters
• Vapor barrier — Wet clothing against skin accelerates heat loss
• Protect the head and neck — Major heat loss areas

---

2. Hemorrhage Control Becomes Harder

Cold doesn’t just affect the casualty — it affects you and your equipment.

Dexterity Loss

• Fine motor skills degrade rapidly in cold
• Gloved hands are less precise
• Tourniquets are harder to manipulate and tighten
• Windlass rods slip more easily

Assessment Challenges

• Cold, blanched skin mimics shock — Pale, cool skin is normal in cold; don’t over-diagnose
• Capillary refill is unreliable — Cold causes peripheral vasoconstriction regardless of volume status
• Pulse assessment is harder — Vasoconstriction makes pulses difficult to palpate

Clotting Issues

• Blood clots slower when the limb is cold — Local hypothermia impairs coagulation at the wound site
• Hemostatic agents may work slower — Combat Gauze and similar products need warmth to activate optimally
• Wound packing is harder — Stiff fingers, stiff gauze, cold wound

Adaptations

• Keep TQs accessible and pre-staged (not buried in a frozen pack)
• Practice applying TQs with gloves — your bare hands won’t be an option
• Warm hemostatic gauze against your body before use if possible
• Tighten TQs extra — they may loosen as materials stiffen

---

3. Airway and Respiration Challenges

Cold air and cold equipment create unique airway and breathing problems.

Physiological Effects

• Cold air triggers bronchospasm — Even non-asthmatics can experience airway reactivity
• Respiratory fatigue happens faster — Cold air increases the work of breathing
• Secretions thicken — Mucus becomes more viscous and harder to clear

Equipment Issues

• BVM valves stiffen — Bag-valve-masks may not function properly in extreme cold
• Fogging kills visibility — Exhaled breath fogs masks, glasses, and scopes
• NPA lubricant may freeze — Water-based lubricants can ice up
• Oxygen delivery is affected — O2 regulators can freeze

Adaptations

• Keep BVM and airway equipment warm (inside clothing layer)
• Use anti-fog solutions or accept reduced visibility
• Have backup airway plans — if one device fails, have another ready
• Monitor respiratory rate closely — fatigue may present as slowing rate

---

4. Wound Care Complications

Open wounds in cold environments face unique challenges beyond bleeding.

Tissue Damage

• Open wounds freeze — Exposed tissue is vulnerable to frostbite
• Freezing causes additional tissue damage — Cellular ice crystal formation destroys tissue
• Frostbitten tissue looks like dead tissue — Don’t debride frozen tissue in the field

Dressing Challenges

• Dressings harden — Gauze and bandages stiffen and lose conformability
• Adhesives fail — Tape, chest seals, and occlusive dressings lose adhesiveness in cold
• Irrigation is difficult — Saline freezes; using it can cause additional cold injury

Infection Risk

• Cold weather increases infection risk — Impaired perfusion reduces immune response
• Wounds stay contaminated longer — Delayed healing in cold
• Evacuation delays compound the problem

Adaptations

• Cover wounds immediately — exposed tissue freezes in minutes
• Warm dressings against your body before applying
• Carry chest seals in an inner pocket to maintain adhesive function
• Skip irrigation in extreme cold — cover and evacuate

---

5. Gear and Evacuation Considerations

Your equipment and evacuation capabilities are degraded in cold weather.

Equipment Failures

Item	Cold Weather Problem
Elastic bandages	Lose stretch
Medical tape	Loses adhesiveness
Batteries	Die 2-3x faster
Plastics	Become brittle, crack
Metal tools	Freeze to wet skin/gloves
Zippers	Ice shut
IV tubing	Stiffens, fluids freeze
Chest seals	Lose adhesion

Communication Issues

• Radio batteries fail faster — Cold accelerates battery drain
• Touchscreens may not work — Gloves and cold fingers don’t register
• Backup communication is essential — Assume primary will fail

Evacuation Complications

• Ropes and straps freeze — Become stiff and hard to manipulate
• Litters crack in extreme cold — Plastic components become brittle
• Ground movement is slower — Snow, ice, and cold slow everything
• Helicopter operations may be limited — Weather and visibility constraints
• Evacuation times multiply — What takes 30 minutes in summer may take 2 hours

Adaptations

• Keep critical items warm (batteries, seals, tape) in inner pockets
• Pre-stage gear for rapid access — frozen zippers and stiff pack fabric slow you down
• Plan for longer timelines in every phase
• Communicate evacuation delays to receiving facility
• Have redundancy for everything critical

---

The Cold Weather MARCH Adjustment

When operating in cold, mentally add these considerations to each MARCH step:

MARCH Step	Cold Weather Addition
M — Massive Hemorrhage	TQs harder to apply, clotting impaired, dexterity lost
A — Airway	Cold air bronchospasm, equipment stiffens, fogging
R — Respiration	BVM valves stiffen, respiratory fatigue, chest seals may fail
C — Circulation	Skin color unreliable, IV fluids can freeze, pulses hard to find
H — Hypothermia	Already happening — aggressive prevention from first contact