Comparative effectiveness of helicopter emergency medical services compared to ground emergency medical services

Aeromedical Transport for Critically Ill Patients

Aeromedical transport (AMT) is an integral part of healthcare systems worldwide. In this article, the personnel and equipment required, associated safety considerations, and evidence supporting the use of AMT is reviewed, with an emphasis on helicopter emergency medical services (HEMS). Indications for HEMS as guideded by the Air Medical Prehospital Triage Score are presented. Lastly, physiologic considerations, which are important to both AMT crews and receiving clinicians, are reviewed.

Prehospital interventions and outcomes in traumatic cardiac arrest: a population-based cohort study using the Danish Helicopter Emergency Medical Services data

BACKGROUND AND IMPORTANCE

Traumatic cardiac arrest is associated with poor prognosis, and timely evidence-based treatment is paramount for increasing survival rates. Physician-staffed helicopter emergency medical service use in major trauma has demonstrated improved outcomes. However, the sparsity of data highlights the necessity for a comprehensive understanding of the epidemiology of traumatic cardiac arrest.

OBJECTIVES

The primary objective of the present study was to evaluate survival and return of spontaneous circulation (ROSC) and to investigate the characteristics of patients with traumatic cardiac arrest assessed by the Danish HEMS.

DESIGN

This was a population-based cohort study based on data from the Danish helicopter emergency medical service database.

SETTINGS AND PARTICIPANTS

The study included all patients assessed by the Danish helicopter emergency medical services between 2016 and 2021.

OUTCOME MEASURES AND ANALYSIS

Data were analysed using descriptive statistics, non-parametric testing and logistic regression analyses. Descriptive analysis of prehospital interventions included cardiopulmonary resuscitation, defibrillation, airway management, administration of blood products, and thoracic decompression. The primary outcome was 30-day survival, and the key secondary outcome was prehospital ROSC.

MAIN RESULTS

A total of 223 patients with TCA were included. The median age was 54 years (IQR 34-68), and the majority were males. Overall, 23% of patients achieved prehospital ROSC, and the 30-day survival rate was 4%. Factors associated with an increased likelihood of ROSC were an initial shockable cardiac rhythm, odds ratio (OR) of 3.78 (95% CI 1.33-11.00) and endotracheal intubation, OR 7.10 (95% CI 2.55-22.85).

CONCLUSION

This study highlights the low survival rates observed among patients with traumatic cardiac arrest assessed by helicopter emergency medical services. The findings support the positive impact of an initial shockable cardiac rhythm and endotracheal intubation in improving the likelihood of ROSC. The study contributes to the limited literature on traumatic cardiac arrests assessed by physician-staffed helicopter emergency services. Finally, the findings emphasise the need for further research to understand and improve outcomes in this subgroup of cardiac arrest.

A Retrospective Geospatial Simulation Study of Helicopter Emergency Medical Services' Potential Time Benefit Over Ground Ambulance Transport in Northern South Africa

OBJECTIVE

One of the most important benefits of helicopter emergency medical services (HEMS) is a time benefit, either through expedited access to the casualty or a reduction in the transport time to definitive care. However, HEMS utilization does not come without risk to the public and crew or at an insignificant cost. Cost is an essential consideration for health policy decisions, especially in low- to middle-income countries, such as South Africa. The aim of this study was to determine whether there is a time benefit of HEMS dispatch in South Africa compared with simulated driving time. A secondary aim was to determine the distance from the incident site to the hospital at which a time benefit can be guaranteed.

METHODS

A retrospective study was undertaken by comparing the prehospital times of patients who underwent HEMS transportation with simulated ground emergency medical services (GEMS) transportation times. Handwritten patient records of actual flights were reviewed and analyzed. The actual flight times recorded were used to calculate the helicopter transport time, activation to scene time, scene time, and scene to hospital time. Times were assigned based on a nonsimultaneous dispatch model, as is used in South Africa. For each helicopter mission, Google Maps (Google Inc, Mountain View, CA) was used to simulate the fastest ground route from the same location of the incident to the same receiving hospital corrected for typical traffic trends. The actual HEMS and simulated GEMS times were compared using the paired t-test. Linear regression analysis was performed to determine a minimum driving distance at which HEMS provides a time benefit.

RESULTS

A total of 118 HEMS transports were analyzed, the majority of which were trauma related (n = 115, 97%). HEMS transport resulted in a mean time deficit of -15 minutes (95% confidence interval, -18 to -11; P < .05) compared with simulated GEMS drive times. After regression, HEMS transport provides a time benefit at a driving distance greater than 119 km.

CONCLUSION

The current study demonstrated that there was rarely a time benefit for actual primary emergency responses when HEMS was used compared with simulated driving time of GEMS transport. Using a nonsimultaneous dispatch model, a time benefit only occurs when the driving distance from the incident site to the hospital is greater than 119 km. There is an urgent need to critically evaluate HEMS utilization in the South African context.

Direct Trauma Center Access by Helicopter Emergency Medical Services is Associated With Improved Survival After Severe Injury

OBJECTIVE

Evaluate the association of survival with helicopter transport directly to a trauma center compared with ground transport to a non-trauma center (NTC) and subsequent transfer.

SUMMARY BACKGROUND DATA

Helicopter transport improves survival after injury. One potential mechanism is direct transport to a trauma center when the patient would otherwise be transported to an NTC for subsequent transfer.

METHODS

Scene patients 16 years and above with positive physiological or anatomic triage criteria within PTOS 2000-2017 were included. Patients transported directly to level I/II trauma centers by helicopter were compared with patients initially transported to an NTC by ground with a subsequent helicopter transfer to a level I/II trauma center. Propensity score matching was used to evaluate the association between direct helicopter transport and survival. Individual triage criteria were evaluated to identify patients most likely to benefit from direct helicopter transport.

RESULTS

In all, 36,830 patients were included. Direct helicopter transport was associated with a nearly 2-fold increase in odds of survival compared with NTC ground transport and subsequent transfer by helicopter (aOR 2.78; 95% CI 2.24-3.44, P <0.01). Triage criteria identifying patients with a survival benefit from direct helicopter transport included GCS≤13 (1.71; 1.22-2.41, P <0.01), hypotension (2.56; 1.39-4.71, P <0.01), abnormal respiratory rate (2.30; 1.36-3.89, P <0.01), paralysis (8.01; 2.03-31.69, P <0.01), hemothorax/pneumothorax (2.34; 1.36-4.05, P <0.01), and multisystem trauma (2.29; 1.08-4.84, P =0.03).

CONCLUSIONS

Direct trauma center access is a mechanism driving the survival benefit of helicopter transport. First responders should consider helicopter transport for patients meeting these criteria who would otherwise be transported to an NTC.

Air Versus Ground Transport Times in an Urban Center

PURPOSE

Given that the benefits of helicopter transport vary with geography and healthcare systems, we assessed transport times for rotor wing versus ground transport over a 10 year period in an urban setting.

MATERIALS AND METHODS

All completed transports from 153 sending hospitals in New England from 2009 through 2018 to 8 local tertiary care centers were extracted from an administrative database. The primary outcome of interest was patient-loaded transport time for rotor wing versus ground transports. Overall, 25,483 patient transports met the inclusion criteria and were included in this study. We assessed patient-loaded transport time for all transports, and determined mean time to arrive at the scene, scene to patient time, the bedside time, and distance at which the patient-loaded transport time was faster for rotor wing than for ground transport. We also performed subgroup analyses, evaluating transport times by time of day, day of the week, and destination.

RESULTS

The most common indication for transport was adult trauma, (n = 6,008, 23.6%) followed by adult cardiac (n = 4359, 17.1%), adult neuro (3729 14.6%), and adult medical (n = 3691, 14.5%). The median miles traveled for all transports was 26.0, IQR 14-38, ranging from 1 to 264 miles. The median patient-loaded transport time was 27 min (IQR 15-40) for all transports. Nearly all time intervals were shorter for rotor wing versus ground transports, and patient-loaded transport time was significantly shorter at 15 minutes compared to 38 minutes (IQR 12-22 vs 28-33, p < 0.001). There was no distance at which the patient-loaded transport time was faster for ground transport than for rotor wing.

CONCLUSIONS

In over 25,000 transports over 10 years, in a compact metropolitan area with relatively short transport distances and times, the use of the helicopter was associated with substantial time savings.

Factors Affecting Interfacility Transport Intervals in Stroke Patients Transferred for Endovascular Therapy

Objective: To describe interfacility transfer (IFT) intervals, transfer vehicle type, and levels of care in patients with large vessel occlusion (LVO) strokes transferred for emergent endovascular therapy (EVT).Methods: We included all patients transferred by a single IFT agency in the state of Indiana from July 1, 2018 to December 1, 2020 to a comprehensive stroke center in Indianapolis for emergent EVT. Data were collected from the transfer center electronic medical records and matched to IFT and receiving hospital data.Results: Two hundred eighty-eight patients were included, of which 150 (52.0%) received EVT. The median call-to-needle interval (from call to the transfer center to EVT needle puncture) was 155.5 minutes (IQR 135.8-195.3). The median resource activation interval (call to the transfer center to IFT deployment) was 16 minutes (IQR 10-27 minutes); the median IFT response interval (call to IFT to arrival of the transferring unit) was 34 minutes (IQR 25-43 minutes); the median pre-transfer interval (call to the transfer center until departure from the sending hospital) was 60.4 minutes (IQR 47.1-72.6); and the median sending hospital interval at bedside was 25 minutes (IQR 20-30 minutes). Most patients (197, 68.4%) were sent via critical care rotor. Only 61 (21.2%) required interventions other than tissue plasminogen administration, such as titration of actively transfusing medications (e.g., nicardipine, propofol) (37 of 61, 59.7%), or intubation or ventilator management (25 of 61, 40.3%). Patients sent via critical care rotor had longer sending hospital intervals (26 minutes, IQR 22-32, vs 19 minutes, IQR 16-25; p < 0.001) but shorter transfer intervals than those sent via critical care ground.Conclusions: At longer distances, rotor transport saved significant time specifically in the total IFT interval of patients with LVO strokes. Emphasizing processes to reduce the resource activation interval and the sending hospital interval may help reduce the overall time-to-EVT.

Characteristics of patients who received helicopter emergency medical services in Japan from 2012 to 2019: a retrospective analysis of data from Tochigi Prefecture

Background

Helicopter Emergency Medical Services (HEMS) has been in operation in Japan since 2001, allowing patients almost anywhere in the nation to receive on-scene emergency treatment from physicians. However, there is insufficient literature on the characteristics of the patients who use Japanese HEMS. Thus, this study aimed to investigate the overall characteristics of patients receiving HEMS care within a single prefecture in Japan.

Methods

We retrospectively analyzed the data of 5163 patients—in Tochigi Prefecture—who received HEMS care from 2012 to 2019. Descriptive statistics were used to analyze the following aspects of care: diagnosis, severity, background characteristics, geographical and environmental variables, immediate pre-hospital intervention, transportation type, and short-term clinical outcomes.

Results

Among 7370 HEMS requests received during the study period, treatment was provided to 5163 patients (1.8 cases per day; 3489 men [67.6%]). Nearly 55% (n = 2856) of patients were aged above 60 years. Age peaks were observed at 0–9 years and 60–69 years. The median distance from the base hospital to the site was 26.7 km. The age-standardized rate of HEMS treatment was 30.3 patients per 100,000 people. Cases of trauma and cardiovascular diseases were the most common (65.3%). Most individuals aged 0–9 years and 60–69 years had neurological disease (seizures accounted for 80.5% of this group) and cardiovascular disease, respectively. The number of patients was similar across all four seasons. After immediate pre-hospital intervention, 81.6% of patients receiving HEMS care were transferred by the helicopter ambulance (53.4% and 28.2% to the base hospital and to other hospitals, respectively). Overall, 56.6% of patients receiving HEMS care were transferred to the base hospital, and the short-term recovery rate was above 75%. Intravenous drip and oxygen administration were the most common pre-hospital interventions (93.1% and 72.7%, respectively).

Conclusions

This study is the first to describe the overall characteristics of HEMS patients using comprehensive data of all HEMS patients in one prefecture in Japan. Further research using both local- and national-level data is needed to accelerate the understanding of the benefits of HEMS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-022-01012-6.

Air Rescue for Pediatric Trauma in a Metropolitan Region of Brazil: Profiles, Outcomes, and Overtriage Rates

Besides ensuring a quick response and transport of trauma victims, helicopter support also involves risks to patients and professionals and has higher operational costs. Studying prehospital triage criteria and their relationship with patient overtriage and outcomes is important, particularly in newly established services and in developing countries with limited health budgets. This could help improve the use of the helicopter rescue and provide better management of the costs and risks related to it. The objective of this study was to determine the epidemiologic and severity profiles of pediatric victims of trauma attended by helicopter in a Brazilian Metropolitan Area to evaluate the outcomes and overtriage rates related to pediatric air rescue in the region. We conducted an observational and retrospective study using 49 hospital and prehospital records from victims of trauma aged <18 years old (yo) assisted by helicopter and then transferred to a tertiary University Hospital. Of the 49 patients, 39 (79.6%) individuals were male, and the mean age was 11.3 yo. Vehicular collisions accounted for 15 (30.6%) of the traumas, and traumatic brain injuries occurred in 28 (57.1%) cases. A total of 29 (59.1%) individuals had severe trauma (Injury Severity Score; ISS >15), and 34 (69.4%) required admission to the intensive care unit. Overtriage varied from 18.4 to 40.8% depending on the criteria used for its definition, being more frequent in individuals aged between 1 and 5 yo. Death occurred in 10 (20.4%) patients. On prehospital evaluation, we classified 29/32 (90.6%) patients with severe trauma according to the Pediatric Trauma Score (PTS ≤8) and 18/25 (72%) according to the Revised Trauma Score (RTS ≤11). Of these, 7/29 (24.1%) and 6/18 (33.3%), respectively, presented ISS <15 at in-hospital evaluation. None of the patients with PTS >8 and 3/7 (42.8%) of those with RTS >11 presented ISS >15. In conclusion, air rescue of pediatric trauma victims was used mainly for critically ill individuals, resulting in rates of overtriage compatible with that found in the literature. PTS showed the lowest rates of overtriage within excellent rates of undertriage.

Association of Pre-Hospital Helicopter Transport with Reduced Mortality in Traumatic Brain Injury in Japan: A Nationwide Retrospective Cohort Study

Patients with traumatic brain injury (TBI) are severely injured patients who require timely, efficient, and specialized care. The effectiveness of helicopter emergency medical services (HEMS) for patients with TBI remains unclear. This study aimed to compare the mortality of patients with TBI transported by HEMS and ground ambulance using propensity score-matching analysis, and to analyze the effects of HEMS in various subpopulations. We conducted a retrospective analysis of the Japan Trauma Data Bank. The study period was from January 2004 to December 2018. The participants were divided into two groups: the helicopter group (patients transported by HEMS) and ground group (patients transported by ground ambulance). The principal outcome was death at hospital discharge. In total, 58,532 patients were eligible for analysis (ground group, n = 54,820 [93.7%]; helicopter group, n = 3712 [6.3%]). Helicopter transport decreased patient mortality at hospital discharge (adjusted odds ratio [OR], 0.83; 95% confidence interval [CI], 0.74-0.92). In propensity score-matched patients, the proportion of deaths at hospital discharge was lower in the helicopter (18.76%) than in the ground (21.21%) group (crude OR, 0.86; 95% CI, 0.77-0.96). The mortality rate in the helicopter group was significantly reduced in many subpopulations, especially in cases of severe TBI with a decreased level of consciousness or higher Injury Severity Score (ISS; Japan Coma Scale score 2 [adjusted OR, 0.60; 95% CI, 0.45-0.80] and ISS ≥50 [adjusted OR, 0.69; 95% CI, 0.48-0.99]). Although the study design was non-randomized, our findings in patients with TBI showed that HEMS conferred a mortality benefit over ground ambulance.

Association between physician-staffed helicopter versus ground emergency medical services and mortality for pediatric trauma patients: A retrospective nationwide cohort study

Background

Helicopter emergency medical services’ (HEMS) effectiveness for pediatric trauma patients remains unclear. We aimed to examine the relation between HEMS and reduced mortality in pediatric trauma patients.

Methods

This retrospective cohort study utilized data from the Japan Trauma Data Bank, a national multicenter clinical trauma database. Participants were aged <18 years, admitted between 2004 and 2015, and transported from the scene to the hospital by HEMS or ground emergency medical services (GEMS). We used a standardized mortality ratio (SMR) weight method, and fitted a marginal structural model to adjust for measured confounders. The SMR weight was calculated using the estimation of the propensity scores. A logistic regression model was used with the baseline independent variables to estimate the propensity score.

Results

Overall, 5,947 patients were identified in our study: 453 were transported by HEMS and 5,494 by GEMS. The mean injury severity score in the HEMS group was significantly higher than that in the GEMS group17.0 (Standard deviation = 11.0) vs 12.2 (Standard deviation = 9.2), p < .001. In-hospital mortality was higher in the HEMS group than that in the GEMS group in the unadjusted analysis (3.8% vs 1.3%, respectively; p < .001). After adjusting for covariates, HEMS transport was not associated with reduced hospital mortality. (odds ratio = 0.82, 95% confidence interval = 0.42–1.58).

Conclusions

HEMS was not associated with reduced mortality among pediatric trauma patients compared with GEMS in this nationwide study. Further investigation is necessary to determine who clearly benefits from HEMS as compared to GEMS.

Association of helicopter transportation and improved mortality for patients with major trauma in the northern French Alps trauma system: an observational study based on the TRENAU registry

BACKGROUND

Prompt prehospital triage and transportation are essential in an organised trauma system. The benefits of helicopter transportation on mortality in a physician-staffed pre-hospital trauma system remains unknown. The aim of the study was to assess the impact of helicopter transportation on mortality and prehospital triage.

METHODS

Data collection was based on trauma registry for all consecutive major trauma patients transported by helicopter or ground ambulance in the Northern French Alps Trauma system between 2009 and 2017. The primary endpoint was in-hospital death. We performed multivariate logistic regression to compare death between helicopter and ground ambulance.

RESULTS

Overall, 9458 major trauma patients were included. 37% (n = 3524) were transported by helicopter, and 56% (n = 5253) by ground ambulance. Prehospital time from the first call to the arrival at hospital was longer in the helicopter group compared to the ground ambulance group, respectively median time 95 [72-124] minutes and 85 [63-113] minutes (P < 0.001). Median transport time was similar between groups, 20 min [13-30] for helicopter and 21 min [14-32] for ground ambulance. Using multivariate logistic regression, helicopter was associated with reduced mortality compared to ground ambulance (adjusted OR 0.70; 95% CI, 0.53-0.92; P = 0.01) and with reduced undertriage (OR 0.69 95% CI, 0.60-0.80; P < 0.001).

CONCLUSION

Helicopter was associated with reduced in-hospital death and undertriage by one third. It did not decrease prehospital and transport times in a system with the same crew using both helicopter or ground ambulance. The mortality and undertriage benefits observed suggest that the helicopter is the proper mode for long-distant transport to a regional trauma centre.

Time Course of Hoist Operations by the Search and Rescue Helicopter Service in Southeast Norway

INTRODUCTION

Optimal dispatch of emergency medical services relies on accurate time estimates of the various prehospital stages. Hoist rescue work time intervals performed by the search and rescue (SAR) helicopter service in Norway have not been studied to date. We aimed to describe the epidemiologic, operational, and medical aspects of the SAR service in southeast Norway. To complement the prehospital timeline, we performed simulated hoist operations.

METHODS

We reviewed time and patient descriptors and medical interventions in hoist operations performed at a SAR base over 5 y. In addition, a simulation study measuring hoist rescue time intervals was performed. Data are presented as mean±SD, except National Advisory Committee for Aeronautics (NACA) scores, which are presented as modes.

RESULTS

There were 148 hoist operations performed during the study period, involving 180 patients. Time to take-off was 13±7 min. There were 88 patients (49%) who were injured; 53 (29%) had a medical condition, and 39 (22%) were evacuees. The mode of the NACA score was 3. Forty-five patients (25%) had an NACA score of 4 to 6. Medical interventions were performed on 77 patients (43%) in 73 operations (49%). Nine patients (5%) were endotracheally intubated, and 1 thoracostomy was performed. The simulated rescuer access time was 4±2 min, the simulated anesthesiologist access time was 6±2 min, and the simulated hoist extrication time was 13±2 min.

CONCLUSIONS

Hoist rescue was performed in 10% (n=148) of the SAR operations. New information about hoist extrication time intervals can improve rescue helicopter dispatch accuracy.

Logistics of air medical transport: When and where does helicopter transport reduce prehospital time for trauma?

BACKGROUND

Trauma is a time sensitive disease. Helicopter emergency medical services (HEMS) have shown benefit over ground emergency medical services (GEMS), which may be related to reduced prehospital time. The distance at which this time benefit emerges depends on many factors that can vary across regions. Our objective was to determine the threshold distance at which HEMS has shorter prehospital time than GEMS under different conditions.

METHODS

Patients in the Pennsylvania trauma registry 2000 to 2013 were included. Distance between zip centroid and trauma center was calculated using straight-line distance for HEMS and driving distance from geographic information systems network analysis for GEMS. Contrast margins from linear regression identified the threshold distance at which HEMS had a significantly lower prehospital time than GEMS, indicated by nonoverlapping 95% confidence intervals. The effect of peak traffic times and adverse weather on the threshold distance was evaluated. Geographic effects across EMS regions were also evaluated.

RESULTS

A total of 144,741 patients were included with 19% transported by HEMS. Overall, HEMS became faster than GEMS at 7.7 miles from the trauma center (p = 0.043). Helicopter emergency medical services became faster at 6.5 miles during peak traffic (p = 0.025) compared with 7.9 miles during off-peak traffic (p = 0.048). Adverse weather increased the distance at which HEMS was faster to 17.1 miles (p = 0.046) from 7.3 miles in clear weather (p = 0.036). Significant variation occurred across EMS regions, with threshold distances ranging from 5.4 to 35.3 miles. There was an inverse but non-significant relationship between urban population and threshold distance across EMS regions (ρ, -0.351, p = 0.28).

CONCLUSION

This is the first study to demonstrate that traffic, weather, and geographic region significantly impact the threshold distance at which HEMS are faster than GEMS. Helicopter emergency medical services was faster at shorter distances during peak traffic while adverse weather increased this distance. The threshold distance varied widely across geographic region. These factors must be considered to guide appropriate HEMS triage protocols.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Clinical Interventions Account for Scene Time in a Helicopter Emergency Medical Service in South Africa

INTRODUCTION

Helicopter emergency medical services (HEMS) have been associated with a prolonged scene time, compromising the time benefit in an urban setting. Therefore, the clinical benefit offered through additional equipment, skills, and experience of HEMS crews must be investigated to propose the value of HEMS. This study aimed at establishing whether HEMS scene time was associated with the number of clinical interventions performed and improved patient stability.

METHOD

This retrospective, cross-sectional chart review included all primary HEMS cases from June 1, 2013, to May 31, 2015, from a South African helicopter service and extracted the number of clinical interventions and patient stability using the Mainz Emergency Evaluation Score (MEES). We correlated this with scene time using analysis of variance.

RESULTS

Five hundred fourteen clinical interventions were performed on 204 patients. A median of 2 clinical interventions per patient was performed on scene. Performing 1 additional clinical intervention was associated with an approximate 4-minute increase in on-scene time. Some improvement in patient stability was shown by a mean change in the MEES of 0.65 after on-scene intervention, but this did not reach MEES clinical cutoff measures.

CONCLUSION

The number of clinical interventions performed by helicopter crews can account for scene time in a South African HEMS. The clinical interventions performed by helicopter crews tend to have a positive effect on patient stability.

External validation of the Air Medical Prehospital Triage score for identifying trauma patients likely to benefit from scene helicopter transport

BACKGROUND

The Air Medical Prehospital Triage (AMPT) score was developed to identify injured patients who may benefit from scene helicopter emergency medical services (HEMS) transport. External validation using a different data set is essential to ensure reliable performance. The study objective was to validate the effectiveness of the AMPT score to identify patients with a survival benefit from HEMS using the Pennsylvania Trauma Outcomes Study registry.

METHODS

Patients 16 years or older undergoing scene HEMS or ground EMS (GEMS) transport in the Pennsylvania Trauma Outcomes Study registry 2000-2013 were included. Patients with 2 or higher AMPT score points were triaged to HEMS, while those with less than 2 points were triaged to GEMS. Multilevel Poisson regression determined the association of survival with actual transport mode across AMPT score triage assignments, adjusting for demographics, mechanism, vital signs, interventions, and injury severity. Successful validation was defined as no survival benefit for actual HEMS transport in patients triaged to GEMS by the AMPT score, with a survival benefit for actual HEMS transport in patients triaged to HEMS by the AMPT score. Subgroup analyses were performed in patients treated by advanced life support providers and patients with transport times longer than 10 minutes.

RESULTS

There were 222,827 patients included. For patients triaged to GEMS by the AMPT score, actual transport mode was not associated with survival (adjusted relative risk, 1.004; 95% confidence interval, 0.999-1.009; p = 0.08). For patients triaged to HEMS by the AMPT score, actual HEMS transport was associated with a 6.7% increase in the relative probability of survival (adjusted relative risk, 1.067; 95% confidence interval, 1.040-1.083, p < 0.001). Similar results were seen in all subgroups.

CONCLUSIONS

This study is the first to externally validate the AMPT score, demonstrating the ability of this tool to reliably identify trauma patients most likely to benefit from HEMS transport. The AMPT score should be considered when protocols for HEMS scene transport are developed and reviewed.

LEVEL OF EVIDENCE

Epidemiologic/prognostic study, level III; therapeutic/care management study, level IV.

Development and Validation of the Air Medical Prehospital Triage Score for Helicopter Transport of Trauma Patients

OBJECTIVE

The aim of this study was to develop and internally validate a triage score that can identify trauma patients at the scene who would potentially benefit from helicopter emergency medical services (HEMS).

SUMMARY BACKGROUND DATA

Although survival benefits have been shown at the population level, identification of patients most likely to benefit from HEMS transport is imperative to justify the risks and cost of this intervention.

METHODS

Retrospective cohort study of subjects undergoing scene HEMS or ground emergency medical services (GEMS) in the National Trauma Databank (2007-2012). Data were split into training and validation sets. Subjects were grouped by triage criteria in the training set and regression used to determine which criteria had a survival benefit associated with HEMS. Points were assigned to these criteria to develop the Air Medical Prehospital Triage (AMPT) score. The score was applied in the validation set to determine whether subjects triaged to HEMS had a survival benefit when actually transported by helicopter.

RESULTS

There were 2,086,137 subjects included. Criteria identified for inclusion in the AMPT score included GCS <14, respiratory rate <10 or >29, flail chest, hemo/pneumothorax, paralysis, and multisystem trauma. The optimal cutoff for triage to HEMS was ≥2 points. In subjects triaged to HEMS, actual transport by HEMS was associated with an increased odds of survival (AOR 1.28; 95% confidence interval [CI] 1.21-1.36, P < 0.01). In subjects triaged to GEMS, actual transport mode was not associated with survival (AOR 1.04; 95% CI 0.97-1.11, P = 0.20).

CONCLUSIONS

The AMPT score identifies patients with improved survival following HEMS transport and should be considered in air medical triage protocols.

Evaluating helicopter emergency medical missions: a reliability study of the HEMS benefit and NACA scores

BACKGROUND

The benefits of the Helicopter Emergency Medical Service (HEMS) and dispatch accuracy are continuously debated, and a widely accepted score to measure the benefits of the mission is lacking. The HEMS Benefit Score (HBS) has been used in Finnish helicopter emergency medical services, but studies are lacking. The National Advisory Committee for Aeronautics (NACA) score is widely used to measure the severity of illness or injury in the pre-hospital setting, but it has many critics due to its subjectivity. We investigated the inter-rater and rater-against-reference reliability of these scores.

METHODS

Twenty-five fictional HEMS missions were created by an expert panel. A total of 22 pre-hospital physicians were recruited to participate in the study from two different HEMS bases. The participants received written instructions on the use of the scores. Intraclass correlation coefficients (ICCs) and mean differences between rater-against-reference values were calculated.

RESULTS

A total of 17 physicians participated in the study. The ICC was 0.70 (95% CI 0.57-0.83) for the HBS and 0.65 (95% CI 0.51-0.79) for the NACA score. Mean differences between references and raters were -0.09 (SD 0.72) for the HBS and 0.28 (SD 0.61) for the NACA score, indicating that raters scored some lower NACA values than reference values formed by an expert panel.

CONCLUSION

The HBS and NACA score had substantial inter-rater reliability. In addition, the rater-against-reference values were acceptable, though large differences were observed between individual raters and references in some clinical cases.

Helicopters and injured kids: Improved survival with scene air medical transport in the pediatric trauma population

BACKGROUND

Helicopter emergency medical services (HEMS) are frequently used to transport injured children, despite unclear evidence of benefit. The study objective was to evaluate the association of HEMS compared with ground emergency medical services (GEMS) transport with outcomes in a national sample of pediatric trauma patients.

METHODS

Patients 15 years or younger undergoing scene transport by HEMS or GEMS in the National Trauma Data Bank from 2007 to 2012 were included. Propensity score matching was used to match HEMS and GEMS patients for likelihood of HEMS transport based on demographics, prehospital physiology and time, injury severity, and geographic region. Absolute standardized differences of less than 0.1 indicated adequate covariate balance between groups after matching. The primary outcome was in-hospital survival, while the secondary outcome was discharge disposition in survivors. Conditional logistic regression determined the association between HEMS versus GEMS transport with outcomes while controlling for demographics, admission physiology, injury severity, nonaccidental trauma, and in-hospital complications not accounted for in the propensity score. Subgroup analysis was performed in patients with a transport time of greater than 15 minutes to capture patients with the potential for HEMS transport.

RESULTS

A total of 25,700 HEMS/GEMS pairs were matched from 166,594 patients. Groups were well matched, with all propensity score variables having absolute standardized differences of less than 0.1. In matched patients, HEMS was associated with a 72% increase in odds of survival compared with GEMS (adjusted odds ratio, 1.72; 95% confidence interval, 1.26-2.36; p < 0.01). Transport mode was not associated with discharge disposition (p = 0.47). Subgroup analysis included 17,657 HEMS/GEMS pairs. HEMS was again associated with a significant increase in odds of survival (adjusted odds ratio, 1.81; 95% confidence interval, 1.24-2.65; p < 0.01), while transport mode was not associated with discharge disposition (p = 0.58).

CONCLUSION

Scene transport by HEMS was associated with improved odds of survival compared with GEMS in pediatric trauma patients. Further study is warranted to understand the underlying mechanisms and develop specific triage criteria for HEMS transport in this population.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Short-term outcome and differences between rural and urban trauma patients treated by mobile intensive care units in Northern Finland: a retrospective analysis

Background

Emergency medical services are an important part of trauma care, but data comparing urban and rural areas is needed. We compared 30-day mortality and length of intensive care unit (ICU) stay for trauma patients injured in rural and urban municipalities and collected basic data on trauma care in Northern Finland.

Methods

We examined data from all trauma patients treated by the Finnish Helicopter Emergency Medical Services in 2012 and 2013. Only patients surviving to hospital were included in the analysis but all pre-hospital deaths were recorded. All data was retrieved from the national Helicopter Emergency Medical Services database, medical records, and the Finnish Causes of Death Registry. Patients were defined as urban or rural depending on the type of municipality where the injury occurred.

Results

A total of 472 patients were included. Age and Injury Severity Score did not differ between rural and urban patients. The pre-hospital time intervals and distances to trauma centers were longer for rural patients and a larger proportion of urban patients had intentional injuries (23.5 % vs. 9.3 %, P <0.001). The 30-day mortality for severely injured patients (Injury Severity Score >15) was 23.9 % in urban and 13.3 % in rural municipalities. In the multivariate regression analysis the odds ratio (OR) for 30-day mortality was 2.8 (95 % confidence interval 1.0 to 7.9, P = 0.05) in urban municipalities. There was no difference in the length of ICU stay or scores. Twenty patients died on scene or during transportation and 56 missions were aborted because of pre-hospital death.

Conclusions

The severely injured urban trauma patients had a trend toward higher 30-day mortality compared with patients injured in rural areas but the length of ICU stay was similar. However, more pre-hospital deaths occurred in rural municipalities. The time before mobile ICU arrival appears to be critical for trauma patients’ survival, especially in rural areas.

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

BACKGROUND

Although survival benefits have been shown at the population level, it remains unclear what drives the outcome benefits for helicopter emergency medical services (HEMS) in trauma. Although speed is often cited as the vital factor of HEMS, we hypothesized a survival benefit would exist in the absence of a time savings over ground emergency medical services (GEMS). The objective was to examine the association of survival with HEMS compared with GEMS transport across similar prehospital transport times.

METHODS

We used a retrospective cohort of scene HEMS and GEMS transports in the National Trauma Databank (2007-2012). Propensity score matching was used to match HEMS and GEMS subjects on the likelihood of HEMS transport. Subjects were stratified by prehospital transport times in 5-minute increments. Conditional logistic regression determined the association of HEMS with survival across prehospital transport times strata controlling for confounders. Transport distance was estimated from prehospital transport times and average HEMS/GEMS transport speeds.

RESULTS

There were 155,691 HEMS/GEMS pairs matched. HEMS had a survival benefit over GEMS for prehospital transport times between 6 and 30 minutes. This benefit ranged from a 46% increase in odds of survival between 26 and 30 minutes (adjusted odds ratio [AOR], 1.46; 95% CI, 1.11-1.93; P < .01) to an 80% increase in odds of survival between 16 and 20 minutes (AOR, 1.80; 95% CI, 1.51-2.14; P < .01). This prehospital transport times window corresponds to estimated transport distance between 14.3 and 71.3 miles for HEMS and 3.3 and 16.6 miles for GEMS.

CONCLUSION

When stratified by prehospital transport times, HEMS had a survival benefit concentrated in a window between 6 and 30 minutes. Because there was no time-savings advantage for HEMS, these findings may reflect care delivered by HEMS providers.

Pretrauma center red blood cell transfusion is associated with reduced mortality and coagulopathy in severely injured patients with blunt trauma

OBJECTIVE

To evaluate the association of pretrauma center (PTC) red blood cell (RBC) transfusion with outcomes in severely injured patients.

BACKGROUND

Hemorrhage remains a major driver of mortality. Little evidence exists supporting PTC interventions to mitigate this.

METHODS

Blunt injured patients in shock arriving at a trauma center within 2 hours of injury were included from the Glue Grant database. Subjects were dichotomized by PTC RBC transfusion. Outcomes included 24-hour mortality, 30-day mortality, and trauma-induced coagulopathy [(TIC), admission international normalized ratio >1.5]. Cox regression and logistic regression determined the association of PTC RBC transfusion with outcomes. To address baseline differences, propensity score matching was used.

RESULTS

Of 1415 subjects, 50 received PTC RBC transfusion. Demographics and injury severity score were similar. The PTC RBC group received 1.3 units of RBCs (median), and 52% were scene transports. PTC RBC transfusion was associated with a 95% reduction in odds of 24-hour mortality [odds ratio (OR) = 0.05; 95% confidence interval (CI), 0.01-0.48; P < 0.01], 64% reduction in the risk of 30-day mortality [hazard ratio = 0.36; 95% CI, 0.15-0.83; P = 0.02], and 88% reduction in odds of TIC (OR = 0.12; 95% CI, 0.02-0.79; P = 0.03). The matched cohort included 113 subjects (31% PTC RBC group). Baseline characteristics were similar. PTC RBC transfusion was associated with a 98% reduction in odds of 24-hour mortality (OR = 0.02; 95% CI, 0.01-0.69; P = 0.04), 88% reduction in the risk of 30-day mortality (hazard ratio = 0.12; 95% CI, 0.03-0.61; P = 0.01), and 99% reduction in odds of TIC (OR = 0.01; 95% CI, 0.01-0.95; P = 0.05).

CONCLUSIONS

PTC RBC administration was associated with a lower risk of 24-hour mortality, 30-day mortality, and TIC in severely injured patients with blunt trauma, warranting further prospective study.

Association between helicopter with physician versus ground emergency medical services and survival of adults with major trauma in Japan

INTRODUCTION

Helicopter emergency medical services with a physician (HEMS) has been provided in Japan since 2001. However, HEMS and its possible effect on outcomes for severe trauma patients have still been debated as helicopter services require expensive and limited resources. Our aim was to analyze the association between the use of helicopters with a physician versus ground services and survival among adults with serious traumatic injuries.

METHODS

This multicenter prospective observational study involved 24,293 patients. All patients were older than 15 years of age, had sustained blunt or penetrating trauma and had an Injury Severity Score (ISS) higher than 15. All of the patient data were recorded between 2004 and 2011 in the Japan Trauma Data Bank, which includes data from 114 major emergency hospitals in Japan. The primary outcome was survival to discharge from hospitals. The intervention was either transport by helicopter with a physician or ground emergency services.

RESULTS

A total of 2,090 patients in the sample were transported by helicopter, and 22,203 were transported by ground. Overall, 546 patients (26.1%) transported by helicopter died compared to 5,765 patients (26.0%) transported by ground emergency services. Patients transported by helicopter had higher ISSs than those transported by ground. In multivariable logistic regression, helicopter transport had an odds ratio (OR) for survival to discharge of 1.277 (95% confidence interval (CI), 1.049 to 1.556) after adjusting for age, sex, mechanism of injury, type of trauma, initial vital signs (including systolic blood pressure, heart rate and respiratory rate), ISS and prehospital treatment (including intubation, airway protection maneuver and intravenous fluid). In the propensity score-matched cohort, helicopter transport was associated with improved odds of survival compared to ground transport (OR, 1.446; 95% CI, 1.220 to 1.714). In conditional logistic regression, after adjusting for prehospital treatment (including intubation, airway protection maneuver and intravenous fluid), similar positive associations were observed (OR, 1.230; 95% CI, 1.017 to 1.488).

CONCLUSIONS

Among patients with major trauma in Japan, transport by helicopter with a physician may be associated with improved survival to hospital discharge compared to ground emergency services after controlling for multiple known confounders.