Contributor: Taylor Lynch MD Educational Pearls Hypothermia is defined as a core body temperature less than 35 degrees Celsius or less than 95 degrees Fahrenheit  Mild Hypothermia: 32-35 degrees Celsius Presentation: alert, shivering, tachycardic, and cold diuresis Management: Passive rewarming i.e. remove wet clothing and cover the patient with blankets or other insulation Moderate Hypothermia: 28-32 degrees Celsius Presentation: Drowsiness, lack of shivering, bradycardia, hypotension Management: Active external rewarming Severe Hypothermia: 24-28 degrees Celsius Presentation: Heart block, cardiogenic shock, no shivering Management: Active external and internal rewarming Less than 24 degrees Celsius Presentation: Pulseless, ventricular arrhythmia Active External Rewarming Warm fluids are insufficient for warming due to a minimal temperature difference (warmed fluids are maintained at 40 degrees vs. a patient at 30 degrees is not a large enough thermodynamic difference) External: Bear hugger, warm blankets Active Internal Rewarming Thoracic lavage (preferably on the patient’s right side) Place 2 chest tubes (anteriorly and posteriorly); infuse warm IVF anteriorly and hook up the posterior tube to a Pleur-evac Warms the patient 3-6 Celsius per hour Bladder lavage Continuous bladder irrigation with 3-way foley or 300 cc warm fluid Less effective than thoracic lavage due to less surface area Pulseless patients ACLS does not work until patients are rewarmed to 30 degrees High-quality CPR until 30 degrees (longest CPR in a hypothermic patient was 6 hours and 30 minutes) Give epinephrine once you reach 35 degrees, spaced out every 6 minutes ECMO is the best way to warm these patients up (10 degrees per hour) Pronouncing death must occur at 32 degrees or must have potassium > 12 References 1. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care - Part 1: Introduction. Circulation. 2005;112(24 SUPPL.). doi:10.1161/CIRCULATIONAHA.105.166550 2. Brown DJA, Burgger H, Boyd J, Paal P. Accidental Hypothermia. N Engl J Med. 2012;367:1930-1938. doi:10.1136/bmj.2.5543.51-c 3. 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 Med. 2019;30(4S):S47-S69. doi:10.1016/j.wem.2019.10.002 4. Kjærgaard B, Bach P. Warming of patients with accidental hypothermia using warm water pleural lavage. Resuscitation. 2006;68(2):203-207. doi:10.1016/j.resuscitation.2005.06.019 5. Lott C, Truhlář A, Alfonzo A, et al. European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances. Resuscitation. 2021;161:152-219. doi:10.1016/j.resuscitation.2021.02.011 6. Plaisier BR. Thoracic lavage in accidental hypothermia with cardiac arrest - Report of a case and review of the literature. Resuscitation. 2005;66(1):99-104. doi:10.1016/j.resuscitation.2004.12.024 Summarized by Jorge Chalit, OMSII | Edited by Meg Joyce & Jorge Chalit, OMSII