The effect of Helicopter Emergency Medical Services on trauma patient mortality in the Netherlands.

Object of this study was to evaluate the effect of the Helicopter Emergency Medical Services (HEMS) on trauma patient mortality and the effect of prehospital time on the association between HEMS and mortality. Trauma patients admitted to a level 1 trauma centre and treated on-scene by the HEMS and Emergency Medical Services (EMS) between 2003 and 2008 were included (n = 186). A control group treated by EMS only (n = 186) was created by matching on ISS, age and severe traumatic brain injury (TBI). Mortality was compared by calculating odds ratios (OR) and numbers needed to treat (NNT), with adjustment for prehospital coded Revised Trauma Score. The effect of prehospital time mortality was tested by a logistic regression. Analyses were made for patients with and without TBI. The OR of early trauma fatality for the HEMS/EMS versus EMS-only groups was 0.8 for patients both with TBI (95% CI 0.4-1.7; NNT: 22) and without TBI (95% CI 0.2-3.3; NNT: 273). The risk of in-hospital mortality was non-significantly higher for patients with TBI in the HEMS/EMS group (OR = 1.3; 95% CI 0.6-2.7; NNT: -15) compared to the EMS-only group and non-significantly lower for patients without TBI (OR = 0.9; 95% CI 0.3-2.5; NNT: 129). After adjustment for prehospital time, the risk of early trauma fatality for patients with TBI treated by the HEMS decreased (OR = 0.6; 95% CI 0.3-1.6). The risk of in-hospital mortality for these patients decreased from 1.3 to 0.8 (95% CI 0.4-2.0). The effect of the HEMS on patients without TBI did not change after adjustment for prehospital time. HEMS treatment is associated with a non-significantly higher risk of in-hospital mortality for patients with TBI and a non-significantly lower risk for patients without TBI. This increased risk of mortality in TBI patients is attributable to the increased prehospital time. These results indicate that HEMS does not have a positive impact on survival.

de Jongh MA ，van Stel HF ，Schrijvers AJ ，Leenen LP ，Verhofstad MH ... -  《-》

Helicopter emergency medical services (HEMS): impact on on-scene times.

Ringburg AN ，Spanjersberg WR ，Frankema SP ，Steyerberg EW ，Patka P ，Schipper IB ... -  《-》

Physician-based emergency medical service deployment characteristics in severe traumatic brain injury: a Dutch multicenter study.

Prehospital guidelines advise advanced life support in all patients with severe traumatic brain injury (TBI). In the Netherlands, it is recommended that prehospital advanced life support is particularly provided by a physician-based helicopter emergency medical service (P-HEMS) in addition to paramedic care (EMS). Previous studies have however shown that a substantial part of severe TBI patients is exclusively treated by an EMS team. In order to better understand this phenomenon, we evaluated P-HEMS deployment characteristics in severe TBI in a multicenter setting. The database included patient demographics, prehospital and injury severity parameters and determinants of EMS or EMS/P-HEMS dispatch in 334 patients with severe TBI admitted to level 1 trauma centres in the Netherlands. P-HEMS was deployed in 62% of patients with severe TBI. Patients treated by the P-HEMS had a higher injury severity score (29 (20-38)) vs. (25 (16-30); P<0.001), more frequently required blood product transfusions (41% vs. 29%; P=0.03) and recurrently suffered from TBI with extracranial injuries (33% vs. 6%; P<0.001) than patients solely treated by an EMS. The prehospital endotracheal intubation rate was higher in the P-HEMS group in isolated TBI (93% vs. 19%; P<0.001) or TBI with extracranial injuries (96% vs. 43%; P<0.001) compared to the EMS group. In the EMS group, more patients were secondary referred to a level 1 trauma centre (32% vs. 4%; P<0.001 vs. P-HEMS). Despite higher injury severity levels in P-HEMS patients, 6-month mortality rates were similar among groups, irrespective of the presence of extracranial injuries in addition to TBI. Deployment of P-HEMS estimated 52% and 72% (P<0.001) in urban and rural regions, respectively, with comparable endotracheal intubation rates among regions. This study shows that a physician-based HEMS was more frequently deployed in patients with severe TBI in the presence of extracranial injuries, and in rural trauma regions. Treatment of severe TBI patients by a paramedic EMS only was associated with a higher incidence of secondary referrals to a level I trauma centre. Our data support adjustment of local prehospital guidelines for patients with severe TBI to the geographical context.

Franschman G ，Andriessen TM ，Boer C ，Van der Naalt J ，Horn J ，Haitsma I ，Vos PE ... -  《-》

Effects of physician-based emergency medical service dispatch in severe traumatic brain injury on prehospital run time.

Prehospital care by physician-based helicopter emergency medical services (P-HEMS) may prolong total prehospital run time. This has raised an issue of debate about the benefits of these services in traumatic brain injury (TBI). We therefore investigated the effects of P-HEMS dispatch on prehospital run time and outcome in severe TBI. Prehospital run times of 497 patients with severe TBI who were solely treated by a paramedic EMS (n = 125) or an EMS/P-HEMS combination (n = 372) were retrospectively analyzed. Other study parameters included the injury severity score (ISS), Glasgow Coma Scale (GCS), prehospital endotracheal intubation and predicted and observed outcome rates. Patients who received P-HEMS care were younger and had higher ISS values than solely EMS-treated patients (10%; P = 0.04). The overall prehospital run time was 74 ± 54 min, with similar out-of-hospital times for EMS and P-HEMS treated patients. Prehospital endotracheal intubation was more frequently performed in the P-HEMS group (88%) than in the EMS group (35%; P<0.001). The prehospital run time for intubated patients was similar for P-HEMS (66 (51-80)min) and EMS-treated patients (59 (41-88 min). Unexpectedly, mortality probability scores and observed outcome scores were less favourable for EMS-treated patients when compared to patients treated by P-HEMS. P-HEMS dispatch does not increase prehospital run times in severe TBI, while it assures prehospital intubation of TBI patients by a well-trained physician. Our data however suggest that a subgroup of the most severely injured patients received prehospital care by an EMS, while international guidelines recommend advanced life support by a physician-based EMS in these cases.

Franschman G ，Verburg N ，Brens-Heldens V ，Andriessen TM ，Van der Naalt J ，Peerdeman SM ，Valk JP ，Hoogerwerf N ，Greuters S ，Schober P ，Vos PE ，Christiaans HM ，Boer C ... -  《-》

Association of direct helicopter versus ground transport and in-hospital mortality in trauma patients: a propensity score analysis.

Helicopter emergency medical services (HEMS) transport of trauma patients has been used for decades. Its use, however, is still a subject of debate, including issues such as high costs, increasing numbers of crashes, and conflicting results regarding effectiveness in reducing mortality. The aim of this study was to examine whether mode of transport (HEMS vs. ground EMS) is independently associated with mortality among trauma patients transported directly from the scene of injury to definitive care. All trauma patients transported directly to a Level I or Level II trauma center by either air or ground EMS over a 4-year period were selected from the Oklahoma State Trauma Registry. Multivariable logistic regression was used to develop propensity scores based on variables measured at the scene of injury. The propensity scores represented the predicted probabilities of a patient being transported by HEMS given a specific set of characteristics and were used as a composite confounding variable in subsequent models of the association of mortality and mode of transport. Along with the propensity scores, Injury Severity Scores (ISS), initial Revised Trauma Score (RTS), and distance from the trauma center were included in a Cox proportional hazards model of the association of mode of transport and 24-hour and 2-week mortality. Overall, the hazard ratio (HR) for 2-week mortality in patients transported by HEMS was 33% lower (HR = 0.67, 95% confidence interval [CI] = 0.54 to 0.84) than in patients transported by ground EMS from the scene of injury, after adjustment for the propensity score and other covariates. In subanalyses, the apparent association of a reduction in the hazard of early mortality among patients transported by HEMS was most evident for patients with an RTS based on injury scene vital signs of 3 to 7 (HR = 0.61, 95% CI = 0.46 to 0.82). The point estimate of the HR was similar (HR = 0.65 95% CI = 0.34 to 1.2) in the 75% of cases who had normal vital signs at the scene of injury, although it was no longer statistically significant because crude mortality was very low (1.7%) in this group. Among those with a RTS of 3 or less at the scene, crude mortality was 58%, and mode of transport was not associated with mortality (HR = 1.02, 95% CI = 0.68 to 1.6). Helicopter EMS transport was associated with a decreased hazard of mortality among certain patients transported from the scene of injury directly to definitive care. Refinements in scene triage and transport guidelines are needed to more effectively select patients that may benefit from HEMS transport from those unlikely to benefit.

Stewart KE ，Cowan LD ，Thompson DM ，Sacra JC ，Albrecht R ... -  《-》