Discussion
burns, injuries
HEAT, COLD, FIRE
The survey responses of 151 fire brigades did show that if patients are protected, this is mainly done with passive heat protection methods like rescue blankets (gold/silver) 70% or woollen blankets 64%. This is remarkable insofar as it is known that passive heat protection methods are practically always inferior to active warming systems, as they cannot actively supply heat, but only partially conserve the remaining heat. For the frequently used rescue foils made of reflective material, there is little robust data to prove effectiveness [The most commonly mentioned active warming system in the survey was halogen floodlight (halogen floodlight only in 41% and halogen floodlight combined with rescue blankets in 39% of all cases). Scientific evidence for their effectiveness is not available. Remarkably, active forced air warming systems have not yet been used prehospital even though the idea of using forced air warming on the scene was already published in 1998 with good arguments [The first volunteer trial A therefore investigated whether halogen floodlights were effective and compared them with a forced air heating system approved for these purposes. The results were clear. In the subjective evaluation of the heating methods, 40% of the volunteers stated that the halogen floodlight had provided only slight heating and 60% of the volunteers stated that the halogen floodlight had done nothing at all. In contrast, all volunteers stated that the forced air warming system had provided substantial warming – a finding which was suggested by another volunteer trial by Stroop et al. [Additionally, the subjective perception of cold during the trial measured by means of the 0 to 10 NRS scale was significantly lower for subjects receiving forced air warming. This subjective assessment of substantially more heat transfer of forced air warming is confirmed by a significantly higher mean skin temperature and total body heat compared to the halogen floodlight.However, measurements of the air temperature of the forced air warming system showed values of over 60 °C. The highest temperature measured was even 70.5 °C. This was frequently answered by the volunteers by pulling their foot away from the entry point of the hose under the plastic foil. Thermal damage to the skin or other injuries were therefore not observed. However, such high air temperatures would be a risk for severe burns in unconscious people or persons with restricted movement [In the second volunteer trial B, it was therefore examined whether a forced air warming system approved in the clinic is also effective and how this compares to effective insulation using a fleece blanket.Here, too, the results were clear. 15.6% of the volunteers felt clearly warmed by the fleece blanket, whereas this was the case in 90.6% of the cases with the forced air warming system. Likewise, in trial A the cold perception was significantly lower for the forced air warming. This subjective assessment of the heat protection methods is also supported by objective data. Both methods resulted in an increase in mean skin temperature and total body heat. However, the values were significantly higher for the forced air warming system.Even though the comparison of the data between the two studies can only be made with great caution, as they were two separate studies with different volunteers, the results can be take as an indicator that the insulation with a fleece blanket might be better than the use of a halogen floodlight. However, the use of forced air warming seems to be more effective than insulation. As an additional factor, halogen floodlights are increasingly replaced by LED floodlights, which do not produce relevant warming radiation. As a reaction to this, some infrared devices explicitly for heating are available (i.e. Hypothermsave ®), but rarely used on scene.The comparison of the data collected here with the literature is complicated due to very little data available. In a study by Thomassen et al. [