Hypothermia

Hypothermia is diagnosed by a core body temperature below 35°C (95°F). Surface or routine thermometers may be inadequate at low temperatures; suspected hypothermia warrants measurement with a low-reading device capable of assessing deep body temperature. Wiley+2WileyThermoregulatory Failure in the Elderly - Wongsurawat - 1990annemergmedAccidental Hypothermia: Peritoneal DialysisacepConsiderations During Cold Weather Ops for LEO and TMPs | Tactical and Law Enforcement Medicine

Clinical severity tracks imperfectly with a single temperature measurement because environmental exposure, comorbidity, duration of cooling, trauma, intoxication, and measurement limitations may modify presentation. In early hypothermia, patients may remain alert and shiver. With progressive cooling, cognition deteriorates, lethargy and reduced interest in self-protection develop, and paradoxical undressing may occur. At lower temperatures, rigidity, slowed or absent respirations, weak pulses, hypotension, arrhythmias, and apparent absence of cardiorespiratory activity can occur. acepacepConsiderations During Cold Weather Ops for LEO and TMPs | Tactical and Law Enforcement Medicine

A core temperature below 30°C defines severe hypothermia in the cited resuscitation literature and is associated with substantial suppression of cerebral blood flow and cerebral oxygen requirement. This physiology can complicate bedside assessment and supports cautious interpretation of absent or profoundly reduced vital signs. AHA JournalsAHA JournalsPart 8: Advanced Challenges in Resuscitation | Circulation

The available Wilderness Medical Society guideline excerpts describe a structured approach to out-of-hospital evaluation and treatment of accidental hypothermia, but the supplied evidence does not provide sufficient detail to specify exact rewarming rates, fluid temperatures, extracorporeal criteria, or drug dosing. AHA Journals+1AHA JournalsPart 10: Adult and Pediatric Special Circumstances of ...ScienceDirectWilderness Medical Society Practice Guidelines for the Out ...

For the unstable or severely hypothermic patient, minimize unnecessary movement while completing airway, breathing, and circulation assessment. Hypothermia may produce profound bradycardia and low cardiac output; at moderate cooling, reduced metabolic demand may preserve supply-demand balance, whereas deeper hypothermia at or below 30°C carries greater arrhythmic risk. Wolters KluwerWolters KluwerMechanisms of action, physiological effects, and... : Critical Care Medicine

Avoid anchoring on environmental exposure alone. Hypothermia can coexist with trauma, hemorrhage, infection, endocrine disease, intoxication, metabolic derangement, or primary cardiac events. The supplied search results support broad evaluation but do not provide a source-supported laboratory or imaging bundle.

Acute hypothermia can produce ECG changes, and shivering-related tremor artifact is specifically described as a common ECG feature. Verify questionable tracings clinically and repeat acquisition after reducing artifact when feasible. WileyWileyChanges in electrocardiogram parameters during acute ...

At moderate therapeutic hypothermia, bradycardia commonly reduces cardiac output, but the associated reduction in metabolic demand may maintain or improve oxygen supply-demand balance. In contrast, deep hypothermia at or below 30°C is associated with more substantial physiologic suppression and increased arrhythmic concern. Wolters KluwerWolters KluwerMechanisms of action, physiological effects, and... : Critical Care Medicine

Monitor temperature trend, rhythm, hemodynamics, consciousness, respiratory status, glucose, and clinical evidence of bleeding or impaired drug handling during prolonged cooling or rewarming. Insulin resistance, impaired drug clearance, and mild coagulopathy are reported physiologic effects of hypothermia. Wolters KluwerWolters KluwerMechanisms of action, physiological effects, and... : Critical Care Medicine

Targeted temperature management, also termed therapeutic hypothermia in some literature, is a controlled intervention used within broader post-cardiac-arrest care rather than a treatment model for all cold-exposed patients. Earlier post-resuscitation guidance cited targets of 33°C to 36°C, while more recent literature describes guideline-supported temperature control between 32°C and 37.5°C. Nature+1NatureTargeted temperature management alleviates post-resuscitation myocardial dysfunction by inhibiting ferroptosisacepInduced Hypothermia after Cardiac Arrest – Does the Method Matter? | Critical Care Medicine Section

The optimal post-arrest temperature target remains debated. The available sources support careful temperature control and avoidance of uncontrolled fever but do not provide enough detail to recommend a specific target, duration, sedation regimen, neuromuscular blockade strategy, or rewarming rate for an individual patient. AHA Journals+2AHA JournalsPart 11: Post–Cardiac Arrest Care: 2025 ...NatureTargeted temperature management alleviates post-resuscitation myocardial dysfunction by inhibiting ferroptosisacepInduced Hypothermia after Cardiac Arrest – Does the Method Matter? | Critical Care Medicine Section

Cooling method affects speed of induction, precision of temperature control, and rewarming control. Endovascular systems may cool faster than other available methods in comparisons cited by ACEP, but the supplied excerpt does not establish superiority for patient-centered outcomes or define a preferred device for U.S. practice. acepacepInduced Hypothermia after Cardiac Arrest – Does the Method Matter? | Critical Care Medicine Section