Hypothermia
Definition
Accidental hypothermia is the unintentional decline of at least 2° C (3.6° F) from the normal human core temperature of 37.2° to 37.7° C (99° to 99.9° F) that occurs in the absence of any primary central nervous system causation. It is both a symptom and a clinical disease entity. Hypothermia occurs in mild, moderate, severe, or profound forms (Table 3-1) and can present as either a primary disorder resulting from environmental exposure or secondary to other causes, such as trauma, infection, or metabolic disease.
General Treatment
1. Consider rescuer scene safety factors, including unstable snow, ice, and rock fall.
2. Handle all patients suspected of having moderate or severe hypothermia carefully to avoid unnecessary jostling or sudden impact. Rough handling can cause ventricular fibrillation. Consider aeromedical evacuation.
3. The rescuer should stabilize injuries, protect the spine, splint fractures, and cover open wounds (Box 3-1).
Box 3-1 Preparing Hypothermic Patients for Transport
1. The patient must be dry. Gently remove or cut off wet clothing, and replace it with dry clothing or a dry insulation system. Keep the patient horizontal, and do not allow exertion or massage of the extremities.
2. Stabilize injuries (e.g., place spine fractures in the correct anatomic position). Open wounds should be covered before packaging.
3. Initiate heated fluid infusions (IV or IO) if feasible; bags can be placed under the patient’s buttocks or in a compressor system. Administer a fluid challenge.
4. Active rewarming should be limited to heated inhalation and truncal heat. Insulate hot water bottles in stockings or mittens before placing them in the patient’s axillae and groin.
5. The patient should be wrapped (Fig. 3-1). Begin building the wrap by placing a large plastic sheet on the available surface (floor, ground), and upon this sheet place an insulated sleeping pad. A layer of blankets, sleeping bag, or bubble wrap insulating material is laid over the sleeping pad. The patient is then placed on the insulation. Heating bottles are put in place along with fluid-filled bags intended for infusion, and the entire package is wrapped layer over layer, with the plastic as the final closure. The patient’s face should be partially covered, taking care to create a tunnel to allow access for breathing and monitoring.
4. Prevent further heat loss; insulate the patient from above and below (Box 3-2).
5. Anticipate an irritable myocardium, hypovolemia, and a large temperature gradient between the periphery and the core.
