Emergency treatment of hypothermia

Abstract

This review considers several recent concepts regarding aetiology and treatment of accid‐ental hypothermia. The importance and effectiveness of shivering heat production in the attenuation and reversal of hypothermia is described. Immediately following removal from cold stress, the patient is in danger of a deteriorating condition that may be due to collapse of arterial pressure and/or continued decrease of core temperature. Several controversies are discussed. It is advised that, when possible, patients should be actively but gently warmed as soon as possible (especially if arrival at the emergency department will take greater than 45 min). Extra time should be taken to check for life signs before cardiopulmonary resus‐citation is initiated. Chest compressions should proceed at regular normothermic rates and care should be taken to not overventilate the patient. In the emergency department, several factors should be considered before deciding on a treatment regimen. These factors include level of consciousness, cardiovascular stability, core temperature and the direction of change of core temperature. It may be advantageous to transport the more severely hypothermic patient to a more advanced care facility even though transport time may be greater. See Commentary, page 5.

Environmental Effects on Brain Function

“…Stimulation of the sympathetic nervous system also results in a release of epinephrine and norepinephrine from the adrenal medullae, which increases the cellular metabolic rate, resulting in an elevation of heat production (13). The heart rate increases, as do cardiac output, mean arterial pressure, and ventilation (14). The preoptic area also stimulates the primary motor center to cause shivering, which increases the metabolic rate by up to 500% (13).…”

“…The preoptic area also stimulates the primary motor center to cause shivering, which increases the metabolic rate by up to 500% (13). Shivering can create significant heat production for up to 4 to 6 hours, but subsequently begins to decline (14).…”

“…Mild hypothermia is commonly considered to be present in the 35-Y32-C temperature range (14). The body's compensatory mechanisms are fully functional in cases of mild hypothermia, but ataxia, dysarthria, and apathy are frequently present.…”

Homeothermy in neonatal chicks exposed to low environmental temperature with or without intracerebroventricular administration of corticotropin‐releasing factor

“…Stimulation of the sympathetic nervous system results in a release of epinephrine and norepinephrine from the adrenal medullae, which increases the cellular metabolic rate, resulting in an elevation of heat production [44]. The heart rate increases, as do cardiac output, mean arterial pressure, and ventilation [45]. If the bodyÕs primary response to low-temperature is not adequate, there will be a continued drop in core temperature.…”

Wilderness medicine

“…[65][66][67] The basics of hypothermia resuscitation include prevention of further heat loss, rewarming, and support of physiologic processes. [68,69] Field research with healthy subjects and invasive monitoring has clarified the physiology of cooling and afterdrop. Improvised and commercial methods for preventing further body heat loss are being developed.…”