Hypothermia prevention supplies close out the M.A.R.C.H. sequence because trauma patients lose heat dangerously fast, and cold sabotages the very clotting that bleeding control depends on. The relationship between hypothermia, acidosis, and coagulopathy is serious enough that trauma medicine calls it the lethal triad, and the countermeasure is simple, deliberate, and frequently skipped: insulate the casualty early, from the ground up, and keep them warm through evacuation. Every complete trauma kit carries this layer, and it should be deployed as a matter of routine rather than an afterthought.

The selection covers reflective blankets, heavy-duty casualty wraps, and active-warming hypothermia management systems from trusted trauma brands like North American Rescue, spanning ounce-weight kit staples to full evacuation-grade systems.

Deploy early and insulate underneath: a casualty on cold ground loses heat downward faster than a blanket on top can compensate, so the ground layer is essential, and wet clothing continues to draw heat until it's addressed. Tier the equipment to the mission, with pocket mylar as the universal baseline, durable wraps for real casualty movement, and active-warming systems where evacuation is long or the environment is cold, the standard for professional prolonged field care. Warmth is treatment even when the casualty says they're fine, because trauma blunts the sensation of cold, and the shivering casualty is already behind.

Shop the tiers in hypothermia blankets, pair with sleep systems for planned field exposure, and build the layer into every outdoor medical kit.