Our analysis reveals that the pre-hospital management of severe trauma patients is rather similar between Austria and Germany. The observed results, based on registry data, include the pre-hospital management of patients.
The median overall time of transport and time on-scene of the EMS were 3 minutes shorter in Austria. The effect of this difference could be attributed to the mode of transportation (53.4% helicopter transport in Austria versus 36.6% in Germany). More than half (53.4%) of all Austrian trauma patients were transported to a TC with a helicopter, compared to 36.6% in Germany (P < 0.001). EMS in Austria are profoundly influenced by its geographic alignment and population shifts during peak tourism seasons (Summer and Winter). Fifty percent of Austria’s population lives in small towns or villages scattered all over the country, thereby creating a rural/urban split (50:50). This results in the necessity for adjustments in EMS strategies based on individual country sides. In rural areas, transport times are much longer as distances to medical facilities can be more than 60 km. Therefore, physician-staffed helicopters are predominately used in rural areas, especially in alpine regions where the exclusive usage of ground transportation is difficult or even impossible . Currently, there are 38 helicopter EMS (HEMS) distributed throughout Austria and cover an area of 84.000 square kilometers (1:2211 square kilometers) and 89 in Germany, covering 356.000 square kilometers (1:4000 square kilometers) . In addition, all of the Western, as well as most of the Southern and Central parts of Austria are covered by the Alps where some mountains reach altitudes of up to 3800 meters, relying therefore on a physician-based HEMS . Another reason that might explain the high percentage of helicopter usage in Austria is the increase in the number of trauma patients due to tourism. According to http://www.austria.info, in 2018, 149 million overnight stays by tourists from all over the world were accounted for.
Nevertheless, the potentially beneficial effects of HEMS on patients' outcomes and cost efficiency are still controversially discussed . In summary, trauma patients benefit from HEMS rescue with in-hospital survival as a main outcome parameter. Analyzing different subgroups, older patients, low-energy trauma, and minor injury severity had the most pronounced survival benefit when rescued by HEMS . However, according to the Austrian (OEAMTC) and German (ADAC) Automobile Club, overall, 17.281 and 53.967 HEMS transports to the ED respectively have been carried out in 2019. This correlates to 1.942 HEMS transports per 1 million inhabitants in Austria and 650 transports per 1 million in Germany. The large difference in helicopter transports can further be explained by the overall lack of a regional/national unified algorithm of indications/guidelines for transport. We suggest to explicitly use the HEMS system for trauma patients only a) for the rescue/care of people who have had an accident or are in life-threatening situations, b) for the transport of emergency patients with ISS > 16, c) for transport of rescue or recovery personnel to hard-to-reach regions or, d) for the transport of medicinal products, especially blood products, organ transplants or medical devices. In summary, the usage of the HEMS system in Austria compared to Germany seems too high and should be reevaluated in terms of its on-scene relevance.
Further, this study demonstrates a discrepancy in the pre-hospital fluid administration. A significant difference between the countries was observed for the amount of fluid administered on scene, a median of 500 mL in Austria versus 1000 mL in Germany. This may be due to differences in fluid administration habits, as it can be seen in Switzerland  and in the Dutch  population as well, where 30% less fluid in the pre-hospital setting is being administered when compared to Germany. Kudo et al. elaborate on the importance on achieving a balance between organ perfusion and hemostasis which is critical for optimal fluid resuscitation in trauma patients. “Permissive hypotension” refers to managing trauma patients by restricting the amount of resuscitation fluid and maintaining blood pressure in the lower-than-normal range if there is continuing bleeding during the acute period of injury. However, no study has investigated which subjects would benefit most from this approach, when considering factors such as age, injury mechanism, setting, or the presence or absence of hypotension . The influence of these approaches on coagulation has not been sufficiently examined, even in animal studies and the overall effectiveness of permissive hypotension/ hypotensive resuscitation is still inconclusive and mandates further research [10–12, 21].
There is no evidence on the required volume threshold for trauma patients . Driessen et al. state that the mean Base Excess (BE) at the time of admission to the ED might indicate a better tissue perfusion despite low BP . In Austria, 20.6% compared to 14.7% of Germans arrived at the TC in a hemodynamically unstable condition, associating with a systolic BP of ≤ 90mmHg. The administration of catecholamines recruits unstressed blood volumes and influences the maintenance of blood pressure . This might be a possible explanation of why the observed hemodynamic instability of Austrian patients arriving at the TC was higher as well as the reduced amount of fluid administered on scene. It can further be excluded that the administration of Tranexamic Acid (TXA) is responsible for the difference in systolic BP upon arrival in the TC, as it was equivalent in both countries. Overall, no algorithm on the exact and correct amount of fluid volume in the pre-clinical setting can be recommended by the authors as it is a dependent variable of age, anticoagulation, blood loss and observed injury pattern.
The mechanism of injury as well as various demographic characteristics do not show a relationship amongst individual variables between both countries and were similar to those found in other studies conducted with the TR-DGU [4,6,7,20]. In General, results should primarily be interpreted in terms of their clinical relevance because the large sample size included in this study likely yields a formal significance even in case of minor differences. Although, a notable variation can be observed by combining geriatric age groups (≥ 70 years) of transported patients within one country. It can be emphasized that more severely injured geriatric patients were transported to TCs in Germany compared to Austria. This further correlates with a greater observed ASA score [16, 17] in Germany as patients age increases. Spering et al. suggest that the number of patients with pre-existing medical conditions, classified according to ASA ≥ 3, increase with accumulative age. Hence, as the age of injured patients rises, so does the cumulative percentage of ASA 3–4 . Overall, a larger number of geriatric patients in Germany have been included in this retrospective data analysis, correlating with a higher observed ASA score (Class 3–4). This classification score includes patients with moderate to severe systemic disease and functional limitations up to a severe systemic disease, which is a constant threat to life .