Analysis of tourniquet pressure over military winter clothing and a short review of combat casualty care in cold weather warfare

Figures & data

Table 1. Number of applications with pressure over 180 mmHg out of 20 applications over different clothing setups (CAT: Combat Application Tourniquet® Generation 7, SAMXT: SAM® Extremity Tourniquet, SOFTT: SOF® Tactical Tourniquet Wide Generation 4).

Clothing setup	CAT	SAMXT	SOFTT
undressed	20	19	17
Bundeswehr Combat Uniform trousers	20	20	18
Bundeswehr Uniform insulation sublayer + Bundeswehr Combat Uniform trousers	20	20	4
Bundeswehr Combat Uniform trousers + Bundeswehr Uniform rain trousers	20	20	9
Bundeswehr Combat Uniform trousers + Bundeswehr Uniform insulation trousers	20	20	17
Bundeswehr Combat Uniform trousers + Bundeswehr Uniform insulation trousers + Bundeswehr Uniform rain trousers	20	20	8

Table 2. Differences between cold exposure in civilian and military circumstances.

Objective	Civilian	Military
Preparation time	Long preparation time	Potentially with short notice
Freedom of movement	Unlimited	Limited
Time in cold	Rather short	Potentially long (mission accomplishment)
Shelter option	Mostly given	Maybe limited, depending on the tactical situation
Criteria to terminate activity in the cold	Own choice	Mission accomplishment
Performance requirement	Adaptable	Full combat strength needed
Clothing	Optimal insulation possible	Predominantly military equipment used Optimal insulation not guaranteed
Dexterity	Predominantly non-mandatory	Mandatory to handle military equipment and weapons
Use of heat sources	Whenever available	Maybe limited, depending on the tactical situation
Chain of evacuation and medical treatment	Established	Limited

Table 3. Different types of warfare. Adapted after Lechner at al [14]. FCI: Freezing cold injuries, NFCI: Non-Freezing cold injuries.

Type of warfare	Wind chill temperature	Relevant cold injuries	Risk of cold injury
damp weather warfare	15–0°C	NFCI possible
cold weather warfare	0 – −30°C	FCI possible
arctic warfare	Less than −30°C	FCI in exposed facial skin within 10 to 30 minutes for most people

Table 4. Treatment algorithm with cold weather adaptions. FCI: freezing cold injury; i.V.: intravenous; i.O.: intraosseous, i.N.: intranasal; t.M.: transmucosal; AMS: acute mountain sickness; HACE: high altitude cerebral oedema.

MARCH/<C>ABCDE Algorithm	Cold weather caveats	Cold weather adaptions
Massive hemorrhage/critical bleeding	high risk of FCI in distal limb after tourniquet application	Application over clothing
Airway	Stiffness of plastic tubes, tearing of cuffs, FCI on contact points	Periodic cuff pressure controls Use cold air masks and apply oxygen
Respiratory/Breathing	frozen chest seals may crack	Place a vapour barrier above the innermost layer of clothing at the back during “check the back” examination Place an insulating pad within a hypothermia enclosure wrap on a carrying gear under the patient during “check the back” examination Place heat packs on chest and/or axilla (avoid skin contact)
Circulation	high risk of FCI in distal limb after tourniquet application High failure rate with pulse oximetry and peripheral capillary refill time due to peripheral vasoconstriction Difficult venous punction due to vasoconstriction Freezing of i.v. fluids	Checking for blood under water repellent layer, if skin cannot be touched (blood sweep) Checking for damage of insulation clothing (visible padding material) Place a second vapour barrier above the innermost layer of clothing from the front Use of alternative drug delivery methods (i.o., i.n. t.m., oral) Use i.v. heating systems or, if not available, apply fluid in boluses
Head/Disability	Hypothermia, AMS, HACE may reduce mental status	Careful head and neck insulation
Hypothermia/Environment	Hypothermia compromises coagulation	Optimisation of insulation for transport

Lechner R, Küpper T, Tannheimer M. Challenges of military health service support in mountain warfare. Wilderness Environ Med. 2018;29(2):266–274.

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