Am J Emerg Med. 2025 Nov 12;100:46-53. doi: 10.1016/j.ajem.2025.10.053. Online ahead of print.

OBJECTIVE: Helicopter emergency medical services (HEMS) treat patients suffering from a multitude of conditions. Accidental hypothermia, defined as an unintentional drop in core temperature below 35 °C, may occur regardless of age, season, or ambient temperature. The underlying reasons can be cold exposure, impaired thermoregulation, decreased heat production, or increased heat loss. The incidence of accidental hypothermia in HEMS is unclear.

METHODS: This retrospective analysis included patients with a documented temperature < 35 °C attended by a helicopter of the German ADAC air rescue service between 2008 and 2021. The ADAC air rescue service operates 50 helicopters across Germany, conducting more than 50,000 annual missions. The primary outcome was the incidence of hypothermia. Secondary outcomes included incidences during different times of the day and seasons, as well as pre-hospital times.

RESULTS: 707,873 missions revealed 94,091 patients with reliable temperature measurements. Hypothermia in 4244 patients resulted in an incidence of 4.5 % or 0.6 % regarding all missions. Analyzing operational patterns of HEMS (n = 2284) revealed a peak in the morning without association with any season. 1210 patients received medical care at home. Prehospital time (n = 2329) averaged 60 min, which is 10 min faster than comparable German data.

CONCLUSIONS: In summary, hypothermia was shown in 1 out of 22 patients. Temperature was documented infrequently. Given the difficulties of measuring temperature in the field, more accurate devices are necessary. Finally, HEMS crews should consider hypothermia in every patient, even during summer and indoors: better to measure once too often than not at all.

PubMed:41270346 | DOI:10.1016/j.ajem.2025.10.053