Q: Which of the following method is most reliable to measure the rewarming phase in a severely hypothermic patient who is intubated?
C) Infra-red temporal artery
D) Lower one-third of the esophagus
In patients with severe hypothermia lower one-third of the esophagus, and to be precise 24 cm below the larynx, is the most reliable method to track the rewarming phase. This area provides the best surrogate of the cardiac temperature. Upper one-third of the esophagus may be falsely elevated due to humidified (heated) oxygen in the endotracheal-tube (ETT). Though rectal and bladder probes are commonly used and good for mild to moderate hypothermia, but they lag behind in the rewarming phase. Axillary and temporal artery measurement of temperature are external to the body and should not be used.
Danzl D. Accidental hypothermia. In: Wilderness Medicine, 6th ed, Auerbach PS (Ed), Elsevier, Philadelphia 2012. p.115.