injuries poisoning
Hypothermia
Treatment of Hypothermia
Drying and insulation Fluid resuscitation Active rewarming unless hypothermia is mild, accidental, and uncomplicated The first priority is to prevent further heat loss by removing wet clothing and insulating the patient. Subsequent measures depend on how severe hypothermia is and whether cardiovascular instability or cardiac arrest is present. Returning patients to a normal temperature is less urgent in mild hypothermia than in severe hyperthermia. For stable patients, elevation of core temperature by 1° C/hour is acceptable. Fluid resuscitation is essential because patients are typically hypovolemic. Patients are given 500 cc to 2 L of 0.9% saline solution (20 mL/kg for children) IV; if possible, the solution is heated to 40 to 42° C. More fluid is given as needed to maintain perfusion. With moderate to severe hypothermia, core temperature must be stabilized before rewarming the extremities, to prevent sudden cardiovascular collapse (rewarming collapse) when peripheral vasculature dilates. Inmild hypothermia(temperature 32 to 35° C) with intact thermoregulation (indicated by shivering), insulation with heated blankets and warm fluids to drink are adequate. Active rewarming is required if patients have temperature<32° C, cardiovascular instability, hormone insufficiency (such as hypoadrenalism or hypothyroidism), or hypothermia secondary to trauma, toxins, or predisposing disorders. Inmoderate hypothermia, body temperature is at the warmer end of the range (28 to 32° C), and external rewarming with forced hot air enclosures may be used. External heat is best applied to the thorax because warming the extremities may increase metabolic demands on a depressed cardiovascular system. Insevere hypothermia, patients with lower temperatures (<28° C), particularly those with low blood pressure or cardiac arrest, require core rewarming. Core rewarming options include Inhalation IV infusion Lavage Extracorporeal core rewarming (ECR) Inhalation of heated (40 to 45°C), humidified oxygen via mask or endotracheal tube eliminates respiratory heat loss and can add 1 to 2° C/hour to the rewarming rate. IV crystalloids or blood should be heated to 40 to 42°C, especially with massive volume resuscitations. Closed thoracic lavage through 2 thoracostomy tubes (see How To Do Tube and Catheter Thoracostomy ) is very efficient in severe cases. Peritoneal lavage with dialysate heated to 40 to 45° C requires 2 catheters with outflow suction and is especially useful for severely hypothermic patients who have There are 5 types of ECR: hemodialysis, venovenous, continuous arteriovenous, cardiopulmonary bypass, and extracorporeal membrane oxygenation. ECR measures require a prearranged protocol with appropriate specialists. Although they are intuitively attractive and heroic, these measures are not routinely available, and they are not commonly used in some hospitals. Hypotension and bradycardia are expected when core temperature is low and, if due solely to hypothermia, need not be aggressively treated. When needed, Tracheal Intubation after oxygenation must be done gently to avoid precipitating a nonperfusing rhythm. CPR should be withheld if patients have a perfusing rhythm unless true cardiac arrest is confirmed by absence of cardiac motion on bedside cardiac ultrasonography. Treat with fluids and active rewarming. Chest compressions are not done, because Pulses may quickly return with rewarming Chest compressions may convert the perfusing rhythm to a nonperfusing rhythm Patients with a nonperfusing rhythm (ventricular fibrillation or asystole) require Cardiopulmonary Resuscitation (CPR) in Adults . Chest compressions and endotracheal intubation are done. Defibrillation is difficult if body temperature is low; one attempt at maximum energy setting for the defibrillator (200 J for biphasic and 360 J for monophasic) may be made, but if ineffective, further attempts are generally deferred until temperature reaches (1 to 5 mcg/kg/min) or other catecholamine infusions are typically reserved for patients who have disproportionately severe hypotension and who do not respond to fluid resuscitation and rewarming ( Treatment references ). 12 mEq/L [12 mmol/L]) during resuscitation typically indicates a fatal outcome and can guide resuscitation efforts ( Treatment references , 2). 1.Dow J, Giesbrecht GG, Danzl DF, et al: Wilderness Medical Society Clinical Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2019 Update.Wilderness Environ Med30(4S):S47-S69, 2019. doi: 10.1016/j.wem.2019.10.002 2.Musi ME, Sheets A, Zafren K, et al: Clinical staging of accidental hypothermia: The Revised Swiss System: Clinical staging of accidental hypothermia: The Revised Swiss System: Recommendation of the International Commission for Mountain Emergency Medicine (ICAR MedCom).Resuscitation162:182, 2021. doi: 10.1016/j.resuscitation.2021.02.038 