Hypothermia

Defined by core body temperature <35°C (<95°F).

Classified as mild, moderate, or severe according to clinical features.

Core temperature measured in the lower third of the oesophagus correlates well with pulmonary artery temperature and is preferred in patients with a secure airway. A low-reading tympanic thermistor-based thermometer is a less invasive alternative.

Initial management should focus on stopping further cooling. This includes removing the patient from the cold environment, careful removal of wet or cold clothing, insulation, warming the body, securing the airway, monitoring breathing and circulation, and maintaining circulation using warm intravenous fluids.

If cardiac arrest occurs, management strategies and criteria for termination of resuscitation must not be extrapolated from those used in normothermic arrest. Patients who have sustained a hypothermic cardiac arrest should ideally be re-warmed in a specialist centre using Extracorporeal Life Support.

Accidental hypothermia is characterised by the unintentional lowering of core body temperature below physiological normal limits, typically <35°C (<95°F).

In patients with trauma, a threshold of 36°C (96.8°F) has been adopted because in this patient group, even milder degrees of hypothermia have devastating consequences in both military and civilian populations.[1]American College of Surgeons. Advanced Trauma Life Support student course manual, 10th edition. Chicago, IL: American College of Surgeons; 2018.[2]Jurkovich GJ, Greiser WB, Luterman A, et al. Hypothermia in trauma victims: an ominous predictor of survival. J Trauma. 1987 Sep;27(9):1019-24. http://www.ncbi.nlm.nih.gov/pubmed/3656464?tool=bestpractice.com