Chemical heat pads were the most common type of AEW equipment used in GA, FW, HEMS, and SAR units. A total of 347 units were reported to have chemical heat pads available in 2024, in contrast to only 73 units in 2013. We also found an increase in the use of hot water bottles, electrical heating blankets, and forced-air warmers. Additionally, three HEMS units reported the use of heat and moisture exchangers for intubated patients, and three units each from FW aircraft, SAR helicopters, and the Norwegian Red Cross Search and Rescue Corps reported having heating cabinets with preheated blankets, which were not available in 2013. This reflects a notable increase in the availability and variety of AEW equipment since 2013 (Fig. 2a).

Guidelines recommend initiating PEW in patients as soon as wet clothing is removed if insulating materials are available [3, 4, 10]. All prehospital services included in the study reported the availability of PEW equipment in their units; the most common equipment included wool and cotton blankets, duvets, space blankets, sleeping bags, and insulated shelter bags, as recommended by the guidelines [3]. The WMS guidelines recommend the use of a multi-layered “burrito model” consisting of a vapor barrier close to the patient, an insulating layer, and a wind- and water-proof outer shell [3, 11, 12].

Most respondents indicated a consistent equipment setup year-round, with no significant differences between summer and winter. However, 40% of FW ambulances, 23% of HEMS, 14% of SAR helicopters, and 25% of USAR units customized their setups for both summer and winter. FW ambulances reported bringing more duvets and carpets in during winter, whereas SAR helicopters and USAR units transitioned to a pre-assembled “burrito model” to prevent and treat cold stress and hypothermia in winter [12]. This may indicate an increased focus on accidental hypothermia during winter, despite it being a potential problem throughout the year.

It is recommended that prehospital healthcare personnel have thermometers available that can measure the core temperature of hypothermic patients [13]. Our investigations show that all professional prehospital search and rescue services had units with thermometers capable of detecting hypothermia (100% of SAR and HEMS units, and 80% of FW aircraft units). In 2013, 100% of the HEMS and SAR units also had hypothermia-detecting thermometers available, whereas there was a decrease in their availability in FW aircraft from 100% in 2013 to 80% in 2024. The number of GAs with available hypothermia-detecting thermometers increased from 13% in 2013 to 83% in 2024; this was largely due to the national acquisition of new multi-monitors with these capabilities during 2013–2014. All the new multimonitors in the professional rescue services came equipped with esophageal probes for direct thermistor-based measurements of core temperature. In contrast, volunteer rescue services reported less access to this equipment; only 15% of the Norwegian Red Cross Search and Rescue Corps units and none of the Norwegian People’s Aid units reported having hypothermia-detecting thermometers available (Table 2). An important limitation to this study is that the specific temperature measurement technology used in the thermometers was not reported in the questionnaire, only if the thermometers were “suitable for detecting hypothermia”.

The recommended site for core temperature measurement is the lower third of the esophagus; the patient mustbe intubated for this to be a viable option. Consequently, care for these patients is eventually transferred to professional rescue services. Most FW, HEMS, and SAR units use esophageal measurements, as these units are staffed with anesthesiologists with extensive critical care experience. Alternatives for the anatomical placement of temperature measurements include the ear canal (epi-tympanic measurement) or rectum. Despite being a viable option, healthcare personnel should be aware that deep rectal measurements do not reflect rapid changes in core temperature as effectively as esophageal measurements [14]. Epi-tympanic measurements may be a suitable alternative, but further validation of measurements in hypothermic patients is needed [15]. There is a risk that epi-tympanic thermometers may display temperatures lower than the actual values [16, 17]. In our study, measurement of rectal and epi-tympanic temperatures was frequently reported.

According to the updated guidelines for the management of accidental hypothermia, all prehospital hypothermic patients with spontaneous circulation should be actively rewarmed, if possible [3]. AEW is also recommended in Norwegian national guidelines for the prehospital treatment of patients with accidental hypothermia [18]. This survey revealed that all services in the Norwegian prehospital chain of care included in the study had units with some form of AEW equipment available and that its availability had increased since 2013 [9].

We achieved a response rate of 70.5%, suggesting that our data accurately reflect the equipment used to handle patients suffering from prehospital cold stress or accidental hypothermia in Norway. Although we aimed to reach the most informed respondents, it was uncertain whether we always reached the most suitable individuals to answer the survey. Some respondents reported a heightened awareness of hypothermia treatment in their department during data collection, which may have changed the standard setups since the survey was conducted. This study also has potential biases, particularly due to interviewer influence during phone surveys. To minimize this, we strictly followed a template and quoted respondents’ answers. Many responses were collected through a direct survey link, reducing interviewer influence.

This study demonstrated high internal validity through comprehensive data collection and the analysis of free-text responses, ensuring reliable and accurate findings. However, its generalizability to other countries may be limited, though recent changes in international guidelines suggest that our findings may still be relevant to global practices for the treatment of cold stress and hypothermia [3].