25th July 2023

Overview

Hypothermia is defined as a core body temperature <5 degrees Celsius. Low-reading thermometers, preferably oesophageal, are required as tympanic thermometers are unreliable in very low temperature states. It can be classified as primary or secondary.

Primary hypothermia is due to environmental exposure with no underlying medical condition that can cause thermodysregulation. Examples include trauma patients, whereby hypothermia is part of the lethal triad, coagulopathy, acidosis, and perioperative hypothermia, which may be deliberate or accidental.

Secondary hypothermia can arise from decreased heat production (hypopituitarism, hypothyroidism, severe malnutrition, hypoglycemia, hypoadrenalism), increased heat loss (burns, erythroderma, vasodilation due to toxic substances), impaired thermoregulation (Parkinson’s disease, multiple sclerosis, pancreatitis, cerebrovascular accident, prolonged cardiac arrest), drugs (beta blockers, neuroleptics, general anaesthetic agents) and other substances (ethanol, sedatives, hypnotics).

Risk factors include elderly patients, cognitive impairment, malnourished and multiple comorbidities.