Survival benefit of helicopter emergency medical services compared to ground emergency medical services in traumatized patients

Abstract

IntroductionPhysician-staffed helicopter emergency medical services (HEMS) are a well-established component of prehospital trauma care in Germany. Reduced rescue times and increased catchment area represent presumable specific advantages of HEMS. In contrast, the availability of HEMS is connected to a high financial burden and depends on the weather, day time and controlled visual flight rules. To date, clear evidence regarding the beneficial effects of HEMS in terms of improved clinical outcome has remained elusive.MethodsTraumatized patients (Injury Severity Score; ISS ≥9) primarily treated by HEMS or ground emergency medical services (GEMS) between 2007 and 2009 were analyzed using the TraumaRegister DGU® of the German Society for Trauma Surgery. Only patients treated in German level I and II trauma centers with complete data referring to the transportation mode were included. Complications during hospital treatment included sepsis and organ failure according to the criteria of the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) consensus conference committee and the Sequential Organ Failure Assessment (SOFA) score.ResultsA total of 13,220 patients with traumatic injuries were included in the present study. Of these, 62.3% (n = 8,231) were transported by GEMS and 37.7% (n = 4,989) by HEMS. Patients treated by HEMS were more seriously injured compared to GEMS (ISS 26.0 vs. 23.7, P < 0.001) with more severe chest and abdominal injuries. The extent of medical treatment on-scene, which involved intubation, chest and treatment with vasopressors, was more extensive in HEMS (P < 0.001) resulting in prolonged on-scene time (39.5 vs. 28.9 minutes, P < 0.001). During their clinical course, HEMS patients more frequently developed multiple organ dysfunction syndrome (MODS) (HEMS: 33.4% vs. GEMS: 25.0%; P < 0.001) and sepsis (HEMS: 8.9% vs. GEMS: 6.6%, P < 0.001) resulting in an increased length of ICU treatment and in-hospital time (P < 0.001). Multivariate logistic regression analysis found that after adjustment by 11 other variables the odds ratio for mortality in HEMS was 0.75 (95% CI: 0.636 to 862).Afterwards, a subgroup analysis was performed on patients transported to level I trauma centers during daytime with the intent of investigating a possible correlation between the level of the treating trauma center and posttraumatic outcome. According to this analysis, the Standardized Mortality Ratio, SMR, was significantly decreased following the Trauma Score and the Injury Severity Score (TRISS) method (HEMS: 0.647 vs. GEMS: 0.815; P = 0.002) as well as the Revised Injury Severity Classification (RISC) score (HEMS: 0.772 vs. GEMS: 0.864; P = 0.045) in the HEMS group.ConclusionsAlthough HEMS patients were more seriously injured and had a significantly higher incidence of MODS and sepsis, these patients demonstrated a survival benefit compared to GEMS.

Helicopter transport improves survival following injury in the absence of a time-saving advantage

“…Several European studies report more advanced interventions in the prehospital environment with a HEMS physician led team. 30–32 However, in the US the concept of HEMS has developed primarily to transport patients rapidly to a trauma center, most often without direct physician involvement. This has been reinforced by early studies demonstrating HEMS is not useful in US urban environments with proximity to trauma centers.…”

Outcomes after helicopter versus ground emergency medical services for major trauma--propensity score and instrumental variable analyses: a retrospective nationwide cohort study

“…Early adopters, such as Germany and the United States, have been operating emergency medical helicopters since 1970 [1], and HEMS have become an important component of pre-hospital care for trauma patients in many countries [2–5]. HEMS can provide faster transport of severely injured patients to highly specialized facilities than ground emergency medical services (GEMS).…”

Emergency aeromedical services in Ireland: a retrospective study for “MEDEVAC112”

“…No one could accurately estimate the time associated with these challenges and rather than provide our estimate we only present the objective figures to which any analyst can then apply an offset to add/subtract time thought to be appropriate to give a better estimation. It has been shown that patients requiring HEMS will require greater on-scene management and this may be the most reasonable explanation of difference in times [17]. The figure of 8.3 min in favour of ground transport implies that it would only take a delay of \10 min to be associated with any of the potential logistical challenges to justify activation of MEDEVAC112 as the appropriate response for the time critical management of these missions.…”

“…Finally the analysis of the cross catchment transfer of patients is an important point to address as it has some potentially important contribution to policy decisions. Firstly, with the provision of this excellent service, the hospitals that provide a dedicated helipad are subject to trauma cases that by their very nature demand greater manpower at the Emergency Department level, on-call radiology services and theatre time as well as an associated significant length of stay [4,17]. Resources to account for this should be apportioned appropriately at a national scale.…”