Mengele M, PH Roche, Fernández P
Fédération Pyrénéenne de médecine de montagne, Toulouse, France
Any prolonged immobilization in the mountains, after an injury, for instance, can lead to hypothermia (a drop in body temperature below 35 ° C) that is produced more or less quickly, depending on the conditions of conduction and convection to which the accident victim is exposed. The defence mechanisms are strong in case of minor injuries that rend the patient immobilized, but they will be limited in the context of multiples traumas or bone marrow injury. The risk of hypothermia complicates the clinical examination that should be rapid and with as little exposure to the cold as possible. The thermal evaluation will be performed with a tympanic thermometer in contact with the tympanic membrane. Mild hypothermia 35-34 ° C, moderate hypothermia 33-30 º C, severe hypothermia 30-28 ° C and very severe hypothermia under 28° C.
Coma, respiratory depression, muscular rigidity, bradycardia, collapse are common that will worsen with the decrease in central temperature and add to the initial traumatic pathology. The patient with hypothermia sees his brain function protected by hypothermia, but his vital prognosis is threatened by the myocardial hyperexcitability.
Peripheral vasoconstriction makes it difficult to establish peripheral venous access, muscular rigidity complicates the intubations, the catecholamines are counter-indicated due to arrhythmogenic effect, and external electrical discharge is ineffective at temperatures under 32 °C.
All these factors make the on-site intervention difficult.
The orientation of these patients depends on the level of hypothermia they are suffering. The patients with severe and very severe hypothermia have to be transferred to centres with extracorporeal circulation.
