Medical Helicopter Accidents in the United States: A 10-Year Review

Analysis of Helicopter Air Ambulance Accidents in the United States From 2010 to 2021

OBJECTIVE

Helicopter air ambulance (HAA) services are essential to air medical transport in the United States. However, HAA accidents, incidents, and fatalities have been a reason for concern for HAA operations. This article analyzes the numbers, proportions, contributing or causal factors, and defining events of HAA accidents in the United States from 2010 to 2021.

METHODS

The National Transportation Safety Board final investigation reports, defining events, findings, and summary data were analyzed for 83 HAA accidents in the United States from 2010 to 2021. The 2 proportions test was used to compare the proportions of fatal HAA accidents between 2010-2015 and 2016-2021.

RESULTS

The data show that 21/47 (45%) of HAA accidents in 2010-2015 and 6/36 (17%) in 2016-2021 were fatal, representing a significant (P < .01) reduction in the proportion of fatal accidents in 2016-2021 from 2010-2015 time period. VFR encounter IMC events accounted for 9/47 (19%) of HAA accidents in 2010-2015 and 1/36 (3%) accident in 2016-2021, representing a significant (P < .05) reduction in VFR encounter IMC accidents.

CONCLUSION

There was a statistically significant decrease in the proportion of fatal HAA accidents from 2010-2015 to 2016-2021, which may be attributable to the changes in the regulatory framework, training protocols, safety awareness initiatives, and technological advancements to address HAA safety.

Evaluation of Physicians' Attitudes Regarding Transport Modalities

OBJECTIVE

Hospital mergers have made interhospital transfers necessary in the consolidation of medical services. Physicians must make decisions on the level of interfacility transport modalities (ITMs). We sought to assess physician knowledge of and comfort with ITMs.

METHODS

A survey was e-mailed to 2,510 physicians in a health care system. Participation was voluntary and anonymous. The mean and median Likert values were calculated overall. Similar calculations were performed for emergency medicine physicians (EMPs) and critical care physicians (CCPs). These calculations were compared with those for noncritical care physicians (NCCPs) using the t-test and Mann-Whitney test.

RESULTS

Of the 181 physicians who responded, 169 physicians identified a specialty. Sixty-nine were EMPs/CCPs, whereas 100 were NCCPs. The mean and median Likert values were statistically significantly higher for EMPs/CCPs compared with NCCPs (P < .0001) in the areas of knowledge of ITMs, comfort in choosing ITMs, and knowledge in choosing ground versus air critical care transport (CCT). The most important factor for using ground or air CCT was patient stability. Sixty percent believed air CCT to be faster than ground.

CONCLUSION

EMPs/CCPs seem to be more comfortable with ITMs than NCCPs. Further research should evaluate whether educational interventions lead to a more appropriate use of ITMs.

A Bayesian Approach on Investigating Helicopter Emergency Medical Fatal Accidents

INTRODUCTION: Helicopter Emergency Medical Service (HEMS) is a mode of transportation designed to expedite the transport of a patient. Compared to other modes of emergency transport and other areas of aviation, historically HEMS has had the highest accident-related fatality rates. Analysis of these accident data has revealed factors associated with an increased likelihood of accident-based fatalities. Here we report the results of an analysis on the likelihood of a fatality based on various factors as a result of a HEMS accident, employing a Bayesian framework.METHODS: A retrospective study was conducted using data extracted from the NTSB aviation accident database from April 31, 2005, to April 26, 2018. Evidence from Baker et al. (2006) was also used as prior information spanning from January 1, 1983, to April 30, 2005.RESULTS: A Bayesian logistic regression was implemented using the prior information and current data to calculate a posterior distribution confidence interval of possible values in predicting accident fatality. The results of the model indicate that flying at night (OR 3.06; 95 C.I 2.14, 4.48; PoD 100), flying under Instrument Flight Rules (OR 7.54; 95 C.I 3.94, 14.44; PoD 100), and post-crash fires (OR 18.73; 95 C.I 10.07, 34.12; PoD 100) significantly contributed to the higher likelihood of a fatality.CONCLUSION: Our results provide a comprehensive analysis of the most influential factors associated with an increased likelihood of a fatal accident occurring. We found that over the past 35 yr these factors were consistently associated with a higher likelihood of a fatality occurring.Simonson RJ, Keebler JR, Chaparro A. A Bayesian approach on investigating helicopter emergency medical fatal accidents. Aerosp Med Hum Perform. 2021; 92(7):563569.

Geospatial assessment of helicopter emergency medical service overtriage

BACKGROUND

Despite evidence of benefit after injury, helicopter emergency medical services (HEMS) overtriage remains high. Scene and transfer overtriage are distinct processes. Our objectives were to identify geographic variation in overtriage and patient-level predictors, and determine if overtriage impacts population-level outcomes.

METHODS

Patients 16 years or older undergoing scene or interfacility HEMS in the Pennsylvania Trauma Outcomes Study were included. Overtriage was defined as discharge within 24 hours of arrival. Patients were mapped to zip code, and rates of overtriage were calculated. Hot spot analysis identified regions of high and low overtriage. Mixed-effects logistic regression determined patient predictors of overtriage. High and low overtriage regions were compared for population-level injury fatality rates. Analyses were performed for scene and transfer patients separately.

RESULTS

A total of 85,572 patients were included (37.4% transfers). Overtriage was 5.5% among scene and 11.8% among transfer HEMS (p < 0.01). Hot spot analysis demonstrated geographic variation in high and low overtriage for scene and transfer patients. For scene patients, overtriage was associated with distance (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.01-1.06 per 10 miles; p = 0.04), neck injury (OR, 1.27; 95% CI, 1.01-1.60; p = 0.04), and single-system injury (OR, 1.37; 95% CI, 1.15-1.64; p < 0.01). For transfer patients, overtriage was associated with rurality (OR, 1.64; 95% CI, 1.22-2.21; p < 0.01), facial injury (OR, 1.22; 95% CI, 1.03-1.44; p = 0.02), and single-system injury (OR, 1.35; 95% CI, 1.18-2.19; p < 0.01). For scene patients, high overtriage was associated with higher injury fatality rate (coefficient, 1.72; 95% CI, 1.68-1.76; p < 0.01); low overtriage was associated with lower injury fatality rate (coefficient, -0.73; 95% CI, -0.78 to -0.68; p < 0.01). For transfer patients, high overtriage was not associated with injury fatality rate (p = 0.53); low overtriage was associated with lower injury fatality rate (coefficient, -2.87; 95% CI, -4.59 to -1.16; p < 0.01).

CONCLUSION

Geographic overtriage rates vary significantly for scene and transfer HEMS, and are associated with population-level outcomes. These findings can help guide targeted performance improvement initiatives to reduce HEMS overtriage.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Characterization of fatal injuries in oil and gas industry-related helicopter accidents in the Gulf of Mexico, 2004-2014

Background

Transportation events are the most common cause of offshore fatalities in the oil and gas industry, of which helicopter accidents comprise the majority. Little is known about injury distributions in civilian helicopter crashes, and knowledge of injury distributions could focus research and recommendations for enhanced injury prevention and post-crash survival. This study describes the distribution of injuries among fatalities in Gulf of Mexico oil and gas industry-related helicopter accidents, provides a detailed injury classification to identify potential areas of enhanced safety design, and describes relevant safety features for mitigation of common injuries.

Methods

Decedents of accidents during 2004–2014 were identified, and autopsy reports were requested from responsible jurisdictions. Documented injuries were coded using the Abbreviated Injury Scale (AIS), and frequency and proportion of injuries by AIS body region and severity were calculated. Injuries were categorized into detailed body regions to target areas for prevention.

Results

A total of 35 autopsies were coded, with 568 injuries documented. Of these, 23.4% were lower extremity, 22.0% were thorax, 13.6% were upper extremity, and 13.4% were face injuries. Minor injuries were most prevalent in the face, neck, upper and lower extremities, and abdomen. Serious or worse injuries were most prevalent in the thorax (53.6%), spine (50.0%), head (41.7%), and external/other regions (75.0%). The most frequent injuries by detailed body regions were thoracic organ (23.0%), thoracic skeletal (13.3%), abdominal organ (9.6%), and leg injuries (7.4%). Drowning occurred in 13 (37.1%) of victims, and drowning victims had a higher proportion of moderate brain injuries (7.8%) and lower number of documented injuries (3.8) compared with non-drowning victims (2.9 and 9.4%, respectively).

Conclusions

Knowledge of injury distributions focuses and prioritizes the need for additional safety features not routinely used in helicopters. The most frequent injuries occurred in the thorax and lower extremity regions. Future research requires improved and expanded data, including collection of detailed data to allow characterization of both injury mechanism and distribution. Improved safety systems including airbags and helmets should be implemented and evaluated for their impact on injuries and fatalities.

Statistical learning for turboshaft helicopter accidents using logistic regression

The objective of this work is to advance the understanding of helicopter accidents by examining and quantifying the association between helicopter-specific configurations (number of main rotor blades, number of engines, rotor diameter, and takeoff weight) and the likelihood of accidents. We leverage a dataset of 8,338 turboshaft helicopters in the U.S. civil fleet and 825 accidents from 2005 to 2015. We use the dataset to develop a logistic regression model using the method of purposeful selection, which we exploit for inferential purposes and highlight the novel insights it reveals. For example, one important question for the design and acquisition of helicopters is whether twin-engine turboshaft helicopters exhibit a smaller likelihood of accidents than their single-engine counterparts, all else being equal. The evidence-based result we derive indicates that the answer is contingent on other covariates, and that a tipping point exists in terms of the rotor diameter beyond which the likelihood of accidents of twin-engines is higher (worse) than that of their single-engine counterparts. Another important result derived here is the association between the number of main rotor blades and likelihood of accidents. We found that for single-engine turboshaft helicopters, the four-bladed ones are associated with the lowest likelihood of accidents. We also identified a clear coupling between the number of engines and the rotor diameter in terms of likelihood of accidents. In summary, we establish important relationships between the different helicopter configurations here considered and the likelihood of accident, but these are associations, not causal in nature. The causal pathway, if it exists, may be confounded or mediated by other variables not accounted for here. The results provided here lend themselves to a rich set of interpretive possibilities, and because of their significant safety implications they deserve careful attention from the rotorcraft community.

Are there Field Triage Criteria that Can Predict Low-Yield Air Medical Transports?

INTRODUCTION

Air medical transport of trauma patients from the scene of injury plays a critical role in the delivery of severely injured patients to trauma centers. Over-triage of patients to trauma centers reduces the system efficiency and jeopardizes safety of air medical crews.

HYPOTHESIS

The objective of this study was to determine which triage factors utilized by Emergency Medical Services (EMS) providers are strong predictors of early discharge for trauma patients transported by helicopter to a trauma center.

METHODS

A retrospective chart review over a two-year period was performed for trauma patients flown from the injury site into a Level I trauma center by an air medical transport program. Demographic and clinical data were collected on each patient. Prehospital factors such as Glasgow Coma Score (GCS), Revised Trauma Score (RTS), intubation status, mechanism of injury, anatomic injuries, physiologic parameters, and any combinations of these factors were investigated to determine which triage criteria accurately predicted early discharge. Hospital factors such as Injury Severity Score (ISS), length-of-stay (LOS), survival, and emergency department disposition were also collected. Early discharge was defined as a hospital stay of less than 24 hours in a patient who survives their injuries. A more stringent definition of appropriate triage was defined as a patient with in-hospital death, an ISS >15, those taken to the operating room (OR) or intensive care unit (ICU), or those receiving blood products. Those patients who failed to meet these criteria were also used to determine over-triage rates.

RESULTS

An overall early discharge rate of 35% was found among the study population. Furthermore, when the more stringent definition was applied, over-triage rates were as high as 85%. Positive predictive values indicated that patients who met at least one anatomic and physiologic criteria were appropriately transported by helicopter as 94% of these patients had stays longer than 24 hours. No other criteria or combination of criteria had a high predictive value for early discharge.

CONCLUSIONS

No individual triage criteria or combination of criteria examined demonstrated the ability to uniformly predict an early discharge. Although helicopter transport and subsequent hospital care is costly and resource consuming, it appears that a significant number of patients will be discharged within 24 hours of their transport to a trauma center. Future studies must determine the impact of eliminating "low-yield" triage criteria on under-triage of scene trauma patients.

The Rapid Emergency Medicine Score: A Critical Appraisal of Its Measurement Properties and Applicability to the Air Retrieval Environment

OBJECTIVE

The Rapid Emergency Medicine Score (REMS) was designed to predict in-hospital mortality using variables that are available in the prehospital setting. The objective of this article is to critically appraise the development and summarize the evidence regarding the measurement properties (sensitivity, reliability and validity) of the REMS.

METHODS

A literature search was performed identifying all studies describing the REMS. The original validation study was critically appraised for its development. All other studies that reported any measurement properties of the REMS were also appraised for evidence of calibration, reliability, and validity.

RESULTS

In total, 26 studies reported on the measurement properties of the REMS. Overall, the REMS was developed with robust methodology and has good sensibility with adequate content and face validity. It is easy to understand and feasible to be calculated within minutes of patient assessment. The REMS has the necessary measurement properties to be both a predictive and evaluative clinical index to measure prehospital severity of illness; however, no studies have adequately addressed the intra or inter-rater reliability of the score.

CONCLUSIONS

There is evidence to support the use of the REMS as a predictive or evaluative instrument. In most studies, it performed as well or better than other illness severity scores in predicting mortality.

Canceled to Be Called Back: A Retrospective Cohort Study of Canceled Helicopter Emergency Medical Service Scene Calls That Are Later Transferred to a Trauma Center

INTRODUCTION

In our trauma system, helicopter emergency medical services (HEMS) can be requested to attend a scene call for an injured patient before arrival by land paramedics. Land paramedics can cancel this response if they deem it unnecessary. The purpose of this study is to describe the frequency of canceled HEMS scene calls that were subsequently transferred to 2 trauma centers and to assess for any impact on morbidity and mortality.

METHODS

Probabilistic matching was used to identify canceled HEMS scene call patients who were later transported to 2 trauma centers over a 48-month period. Registry data were used to compare canceled scene call patients with direct from scene patients.

RESULTS

There were 290 requests for HEMS scene calls, of which 35.2% were canceled. Of those canceled, 24.5% were later transported to our trauma centers. Canceled scene call patients were more likely to be older and to be discharged home from the trauma center without being admitted.

CONCLUSION

There is a significant amount of undertriage of patients for whom an HEMS response was canceled and later transported to a trauma center. These patients face similar morbidity and mortality as patients who are brought directly from scene to a trauma center.

Over-Triage in Casevac Categorisation is Common in Hong Kong

Objective

To review the categorisation of patients who were transferred out from out-lying islands to urban hospitals utilising casualty evacuation (CASEVAC), and to search for possible patient characteristics which might have contributed to mis-categorisation during the ‘non-flying’ hours.

Methods

The medical records of 459 patients, who were transferred out in the year 2009 were reviewed. Correctness of categorisation was determined by 2 independent assessors according to the CASEVAC guidelines. The rates of mis-categorisation between ‘clinic hours’ and ‘AED hours’, and that between the ‘flying’ and ‘non-flying’ hours, were compared. The patients' demographic data and their presenting symptoms were collected and analysed using logistic regression models to identify factors contributing to mis-categorisation.

Results

The mis-categorisation rate was 60.1%. Among them, all were over-categorised. The over-categorisation rates between ‘clinic hours’ and ‘AED hours’, and between ‘flying’ and ‘non-flying’ hours, were not significantly different (p=0.07 and 0.09, respectively). Abnormal pulse rate was significantly associated with over-categorisation (p<0.01). Patients at extremes of age and psychiatric/drunk patients were significantly less likely to be over-categorised (p<0.05 and p<0.01, respectively). There was 20% disagreement between the two assessors when applying the existing CASEVACs guidelines (kappa score 0.58 or ‘moderate agreement’).

Conclusions

Over-triage in CASEVAC categorisation is common irrespective of the time of day. Revision of the current CASEVAC guidelines is recommended. (Hong Kong j.emerg.med. 2013; 20:327-336)

In by helicopter out by cab: the financial cost of aeromedical overtriage of trauma patients

BACKGROUND

Helicopter transport of injured patients is controversial and costly. This study aims to show that a complex trauma algorithm leads to significant aeromedical overtriage at substantial cost. Our secondary outcomes were to compare adjusted mortality and outcomes between air and ground transport and determine predictors of overtriage.

MATERIALS AND METHODS

A 6-y retrospective analysis was conducted of all trauma activations at a Level I center. Patients were dichotomized by transportation method as well as trauma activation criteria. Overtriage was defined as those who were discharged from the emergency department, medically admitted without injuries, or admitted to observation status only. Overtriage and associated charges were calculated for each patient cohort, and multivariate regression models were created to derive adjusted mortality rates and predictors of overtriage.

RESULTS

A total of 4218 patients were treated with 28% arriving by helicopter. Overtriage increased significantly from 51% to 77% with lower tier activation criteria (P < 0.001). Median charges for air-evacuated patients was $10,478 (versus $1008 ground). Eliminating overtriage of air patients would result in a cost savings of $1,316,036 annually. Adjusted mortality between air and ground transport was not significantly different (8.5% versus 10.9%, P = 0.548). Predictors of overtriage included decreasing age, Injury Severity Score, Head Abbreviated Injury Score, nonoperative treatment, and lower tier activation criteria.

CONCLUSIONS

Significant overtriage (52%) and unnecessary air evacuation of minimally injured patients occurs at great financial cost. Revision of trauma activation protocols may result in more judicious air transport use and significant reductions in health care costs.

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.

Reduced Mortality in Severely Injured Patients Using Hospital-based Helicopter Emergency Medical Services in Interhospital Transport

Recent evidence has demonstrated the survival benefits of helicopter transport for trauma patients. The purpose of this study was to evaluate the effectiveness of hospital-based helicopter emergency medical services (H-HEMS) in comparison with ground ambulance transport in improving mortality outcomes in patients with major trauma. Study participants were divided into 2 groups according to type of transport to the trauma center; that is, either via ground emergency medical services (GEMS) or via H-HEMS. The study was conducted from October 2013 to July 2015. Mortality outcomes in the H-HEMS group were compared with those in the GEMS group by using the Trauma and Injury Severity Score (TRISS) analysis. The number of participants finally included in the study was 312. Among these patients, 63 were adult major trauma patients transported via H-HEMS, and 47.6% were involved in traffic accidents. For interhospital transport, the Z and W statistics revealed significantly higher scores in the H-HEMS group than in the GEMS group (Z statistic, 2.02 vs. 1.16; P = 0.043 vs. 0.246; W statistic, 8.87 vs. 2.85), and 6.02 more patients could be saved per 100 patients when H-HEMS was used for transportation. TRISS analysis revealed that the use of H-HEMS for transporting adult major trauma patients was associated with significantly improved survival compared to the use of GEMS.

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.

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.

Injury and fatality risks in aeromedical transport: focus on prevention

BACKGROUND

Aeromedical transport (AMT) is a reliable and well-established life-saving option for rapid patient transfers to health care delivery hubs. However, owing to the very nature of AMT, fatal and nonfatal events may occur. This study reviews aeromedical incidents reported since the publication of the last definitive review in 2003, aiming to provide additional insight into a wide range of factors potentially associated with fatal and nonfatal AMT incidents (AMTIs). We hypothesized that weather and/or visual conditions, postcrash fire, aircraft make and/or type, and time of day all correlate with the risk of AMTI with injury or fatality.

METHODS

Specialty databases were queried for AMTI between January 1, 2003 and July 31, 2015. Additional Internet-based resources were also used to find any additional AMTI (including non-US occurrences) to augment the event sample size available for analysis. Univariate analyses of the collected sample were then performed for association between "fatal crash or injury" (FCOI) and weather/visual conditions, aircraft type and/or make, pilot error, equipment failure, post-incident fire, time of day (6 am-7 pm versus 7 pm-6 am), weekend (Friday-Sunday) versus weekday (Monday-Thursday), season of the year, and presence of patient on board. Variables reaching significance level of P < 0.20 were included in multivariate analysis.

RESULTS

A total of 59 AMTIs were identified. Helicopters were involved in 52 of 59 AMTIs, with 7 of 59 fixed-wing incidents. Comparing pre-2003 data with post-2003 data, we noted a significant decrease in AMTIs per month (0.70 versus 0.39, respectively, P = 0.048), whereas the number of fatalities per year increased slightly (7.20 versus 8.26, p = n/s). In univariate analyses, abnormal weather conditions, impaired visibility, time of incident (7 pm-6 am), aircraft model/make, and post-incident fire all reached statistical significance sufficient for inclusion in multivariate analysis (P < 0.20). Factors independently associated with FCOI included post-incident fire (odds ratio, 19.0; 95% confidence interval, 1.41-255.5) and time of incident between 7 pm and 6 am (odds ratio, 11.2; 95% confidence interval, 1.29-97.2). Weather conditions, impaired visibility, and aircraft model/make were not independently associated with FCOI.

CONCLUSIONS

The present study supports previous observation that post-crash fire is independently associated with FCOI. However, our data do not support previous observations that weather conditions, impaired visibility, or aircraft model/make are independently predictive of fatal AMTI. In addition, this report demonstrates that flights between the hours of 7 pm-6 am may be associated with greater odds of FCOI. Efforts directed at identification, remediation, and active prevention of factors associated with AMTI and FCOI are warranted given the global increase in aeromedical transport.

Factors Associated with the Use of Helicopter Inter-facility Transport of Trauma Patients to Tertiary Trauma Centers within an Organized Rural Trauma System

OBJECTIVE

A review of the literature yielded little information regarding factors associated with the decision to use ground (GEMS) or helicopter (HEMS) emergency medical services for trauma patients transferred inter-facility. Furthermore, studies evaluating the impact of inter-facility transport mode on mortality have reported mixed findings. Since HEMS transport is generally reserved for more severely injured patients, this introduces indication bias, which may explain the mixed findings. Our objective was to identify factors at referring non-tertiary trauma centers (NTC) influencing transport mode decision.

METHODS

This was a case-control study of trauma patients transferred from a Level III or IV NTC to a tertiary trauma center (TTC) within 24-hours reported to the Oklahoma State Trauma Registry between 2005 and 2012. Multivariable logistic regression was used to determine clinical and non-clinical factors associated with the decision to use HEMS.

RESULTS

A total of 7380 patients met the study eligibility. Of these, 2803(38%) were transported inter-facility by HEMS. Penetrating injury, prehospital EMS transport, severe torso injury, hypovolemic shock, and TBI were significant predictors (p<0.05) of HEMS use regardless of distance to a TTC. Association between HEMS use and male gender, Level IV NTC, and local ground EMS resources varied by distance from the TTC. Many HEMS transported patients had minor injuries and normal vital signs.

CONCLUSIONS

Our results suggest that while distance remains the most influential factor associated with HEMS use, significant differences exist in clinical and non-clinical factors between patients transported by HEMS versus GEMS. To ensure comparability of study groups, studies evaluating outcome differences between HEMS and GEMS should take factors determining transport mode into account. The findings will be used to develop propensity scores to balance baseline risk between GEMS and HEMS patients for use in subsequent studies of outcomes.

"Evaluation of a very low-cost and simple teleradiology technique"

This paper describes and analyzes a proposed solution of fundamental limitative factor of teleradiology to overcome the teleradiology usages problems in underdeveloped and developing countries. The goal is to achieve a very simple and cost-efficient way to take advantage of teleradiology in anywhere even in remote and rural areas. To meet the goal of this study, the following methodology which is consists of two main procedures was done: (1) Using a digital camera in order to provide a digital image from radiographs. (2) Using an image compression tool in order to compress digital images. The results showed that there is no significant difference between digital images (non-compress and compress images) and radiographic films. Also, there was a logic relationship between the diagnostic quality and diagnostic accuracy. Since the maximum percent of diagnostic accuracy can be seen among "Good" quality images and the minimum to was related "Poor". The results of our study indicate that a digital camera could be utilized to capture digital images from radiographic films of chest x-ray. To reduce the size of digital images, a lossy compression technique could be applied at compression percent of 50 or less without any significant differences. The compressed images can be sent easily by email to other places for consultation and also they can be stored with a smaller size.

Helicopter emergency medical services for adults with major trauma

BACKGROUND

Although helicopters are presently an integral part of trauma systems in most developed nations, previous reviews and studies to date have raised questions about which groups of traumatically injured people derive the greatest benefit.

OBJECTIVES

To determine if helicopter emergency medical services (HEMS) transport, compared with ground emergency medical services (GEMS) transport, is associated with improved morbidity and mortality for adults with major trauma.

SEARCH METHODS

We ran the most recent search on 29 April 2015. We searched the Cochrane Injuries Group's Specialised Register, The Cochrane Library (Cochrane Central Register of Controlled Trials; CENTRAL), MEDLINE (OvidSP), EMBASE Classic + EMBASE (OvidSP), CINAHL Plus (EBSCOhost), four other sources, and clinical trials registers. We screened reference lists.

SELECTION CRITERIA

Eligible trials included randomized controlled trials (RCTs) and nonrandomized intervention studies. We also evaluated nonrandomized studies (NRS), including controlled trials and cohort studies. Each study was required to have a GEMS comparison group. An Injury Severity Score (ISS) of at least 15 or an equivalent marker for injury severity was required. We included adults age 16 years or older.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data and assessed the risk of bias of included studies. We applied the Downs and Black quality assessment tool for NRS. We analyzed the results in a narrative review, and with studies grouped by methodology and injury type. We constructed 'Summary of findings' tables in accordance with the GRADE Working Group criteria.

MAIN RESULTS

This review includes 38 studies, of which 34 studies examined survival following transportation by HEMS compared with GEMS for adults with major trauma. Four studies were of inter-facility transfer to a higher level trauma center by HEMS compared with GEMS. All studies were NRS; we found no RCTs. The primary outcome was survival at hospital discharge. We calculated unadjusted mortality using data from 282,258 people from 28 of the 38 studies included in the primary analysis. Overall, there was considerable heterogeneity and we could not determine an accurate estimate of overall effect.Based on the unadjusted mortality data from six trials that focused on traumatic brain injury, there was no decreased risk of death with HEMS. Twenty-one studies used multivariate regression to adjust for confounding. Results varied, some studies found a benefit of HEMS while others did not. Trauma-Related Injury Severity Score (TRISS)-based analysis methods were used in 14 studies; studies showed survival benefits in both the HEMS and GEMS groups as compared with MTOS. We found no studies evaluating the secondary outcome, morbidity, as assessed by quality-adjusted life years (QALYs) and disability-adjusted life years (DALYs). Four studies suggested a small to moderate benefit when HEMS was used to transfer people to higher level trauma centers. Road traffic and helicopter crashes are adverse effects which can occur with either method of transport. Data regarding safety were not available in any of the included studies. Overall, the quality of the included studies was very low as assessed by the GRADE Working Group criteria.

AUTHORS' CONCLUSIONS

Due to the methodological weakness of the available literature, and the considerable heterogeneity of effects and study methodologies, we could not determine an accurate composite estimate of the benefit of HEMS. Although some of the 19 multivariate regression studies indicated improved survival associated with HEMS, others did not. This was also the case for the TRISS-based studies. All were subject to a low quality of evidence as assessed by the GRADE Working Group criteria due to their nonrandomized design. The question of which elements of HEMS may be beneficial has not been fully answered. The results from this review provide motivation for future work in this area. This includes an ongoing need for diligent reporting of research methods, which is imperative for transparency and to maximize the potential utility of results. Large, multicenter studies are warranted as these will help produce more robust estimates of treatment effects. Future work in this area should also examine the costs and safety of HEMS, since multiple contextual determinants must be considered when evaluating the effects of HEMS for adults with major trauma.

Probable cause in helicopter emergency medical services crashes: what role does ownership play?

BACKGROUND

The National Transportation Safety Board (NTSB) ranks helicopter emergency medical services (HEMS) as one of the most perilous occupations in the United States, with improvements in its safety of highest priority. As many injured patients are transported by helicopter, this is of particular concern to the trauma community. The use of HEMS is associated with a heightened degree of inherent risk. We hypothesized that this risk is not uniform and varies with the entity providing HEMS, specifically, commercial versus public safety providers.

METHODS

The NTSB accident database was queried to identify all HEMS-involved events for the 15-year period 1998 to 2012. The NTSB investigation report was reviewed to obtain crash details including probable cause. These were analyzed on the basis of HEMS ownership. Statistical analyses were performed using analysis of variance and Fisher's exact test as appropriate.

RESULTS

During the study period, 139 (6.8%) of 2,040 crashes involved HEMS and occurred across 134 cities in 37 states, killing 120 and seriously injuring 146. Of these, 118 involved commercial, 14 not-for-profit, and 7 public safety HEMS. Analyzed in 5-year blocks, no decrease in crash incidence was seen (p = 0.7, analysis of variance). Human and pilot errors were significantly more common among commercial HEMS compared with public safety HEMS (91 of 118 vs. 2 of 7, p = 0.013, and 75 of 116 vs. 1 of 7, p = 0.017, Fisher's exact test). Conditions for which training was not adequate, limited resources, inadequate equipment, and the undertaking of suboptimal trips were identified as key factors. Trauma patients were involved in 34 transports (24.5%), with a fatal or serious outcome in 68 crew/patients on 12 flights.

CONCLUSION

Potentially preventable human and pilot error-related HEMS crashes are significantly more frequent among commercial compared with public safety providers. Deficiencies in training, reduced availability of equipment and resources, as well as questionable flight selection seem to play a key role.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

How often are interfacility transfers of spine injury patients truly necessary?

BACKGROUND CONTEXT

Traumatic spine injuries are often transferred to regional tertiary trauma centers from outside hospitals (OSHs) and subsequently discharged from the trauma center's emergency department (ED) suggesting secondary overtriage of such injuries.

PURPOSE

The aim of the study was to investigate the definitive treatment and disposition of traumatic spine injuries transferred from OSH, particularly those without other trauma injuries or neurologic symptoms.

STUDY DESIGN

This was a retrospective study.

PATIENT SAMPLE

Adult patients presenting to a single Level 1 trauma center with spine injuries were included.

OUTCOME MEASURES

The outcome measures considered in the study were appropriateness of transfer, treatment, and cost.

METHODS

Four thousand five-hundred consecutive adult patients presenting to a single Level 1 trauma center with spine injuries (isolated or polytrauma) were reviewed. This consisted of 1,427 patients (32%) transferred from an OSH ED. All OSH, emergency medical services, and receiving institution (RI) patient records and imaging were reviewed.

RESULTS

Patients who were neurologically intact, nonpolytrauma, and without critical medical issues at the OSH (isolated intact spine transfers) comprised 29% of transfers. Helicopters transported 13% of these patients. The most frequent injuries were compression (26%), burst (17%), and transverse process (10%) fractures. Seventy-eight percent were discharged directly from the RI's ED. Similarly, 15% were not given any formal treatment, 13% had surgery, and 72% given orthosis treatment. The average cost for transportation and ED costs for those discharged from the RI ED were $1,863 and $12,895, respectively. Of the isolated intact spine transfers, 42% were considered to be inappropriate to warrant transfer. This was defined as those sent from an OSH with an orthopedic or neurosurgeon on staff and clearly stable injuries with minimal chance of progressing to instability. Isolated intact spine transfers whose OSH spine imaging was not considered unstable was 25% of transfers with a helicopter used to transport 14% of these patients. Eighty-seven percent were discharged from the ED, whereas only 3% went onto surgery.

CONCLUSIONS

This study is the first to investigate interfacility transfers with spine injuries and found high rate of secondary overtriage of neurologically intact patients with isolated spine injuries. Potential solutions include increasing spine coverage in community EDs, increasing direct communication between the OSH and the spine specialist at the tertiary center, and utilization of teleradiology.

A review of risk analysis and helicopter air ambulance accidents

The Federal Aviation Administration announced a final rule in February 2014 that includes a requirement for helicopter air ambulance operators to institute preflight risk analysis programs. This qualitative study examined risk factors that were described in 22 preliminary, factual, and probable cause helicopter air ambulance accident and incident reports that were initiated by the National Transportation Safety Board between January 1, 2011, and December 31, 2013. Insights into the effectiveness of existing preflight risk analysis strategies were gained by comparing these risk factors with the preflight risk analysis guidance that is published by the Federal Aviation Administration in the Flight Standards Information Management System. When appropriate, a deeper understanding of the human factors that may have contributed to occurrences was gained through methodologies that are described in the Human Factors Analysis and Classification System. The results of this study suggest that there are some vulnerabilities in existing preflight risk analysis guidelines that may affect safety in the helicopter air ambulance industry. The likelihood that human factors contributed to most of the helicopter air ambulance accidents and incidents that occurred during the study period was also evidenced. The results of this study suggest that effective risk analysis programs should provide pilots with both preflight and in-flight resources.

Retrospective review of injury severity, interventions and outcomes among helicopter and nonhelicopter transport patients at a Level 1 urban trauma centre

BACKGROUND

Air ambulance transport for injured patients is vitally important given increasing patient volumes, the limited number of trauma centres and inadequate subspecialty coverage in nontrauma hospitals. Air ambulance services have been shown to improve patient outcomes compared with ground transport in select circumstances. Our primary goal was to compare injuries, interventions and outcomes in patients transported by helicopter versus nonhelicopter transport.

METHODS

We performed a retrospective 10-year review of 14 440 patients transported to an urban Level 1 trauma centre by helicopter or by other means. We compared injury severity, interventions and mortality between the groups.

RESULTS

Patients transported by helicopter had higher median injury severity scores (ISS), regardless of penetrating or blunt injury, and were more likely to have Glasgow Coma Scale scores less than 8, require airway control, receive blood transfusions and require admission to the intensive care unit or operating room than patients transported by other means. Helicopter transport was associated with reduced overall mortality (odds ratio 0.41, 95% confidence interval 0.33-0.39). Patients transported by other methods were more likely to die in the emergency department. The mean ISS, regardless of transport method, rose from 12.3 to 15.1 (p = 0.011) during our study period.

CONCLUSION

Patients transported by helicopter to an urban trauma centre were more severely injured, required more interventions and had improved survival than those arriving by other means of transport.

[Importance of helicopter rescue]

Helicopter emergency medical service (HEMS) have become a main part of prehospital emergency medical services over the last 40 years. Recently, an ongoing discussion about financial shortage and personal shortcomings question the role of cost-intensive air rescue. Thus, the value of HEMS must be examined and discussed appropriately. Since the number of physician-staffed ground ambulances may decrease due to the limited availability of qualified physicians, HEMS may fill the gap. In addition patient transfer to specialized hospitals will require an increasing number of air transports in order to minimize prehospital time. The higher risk ratio for HEMS missions when compared with ground rescue requires a rigorous quality management system. When it comes to missions in remote and exposed areas, the scope of medical treatment must be adjusted to the individual situation. Medical competence is key in order to balance guideline compliant or maximal care versus optimal care characterized as a mission-specific, individualized emergency care concept. Although, medical decision making and treatment is typically based on the best scientific evidence, personal skills, competence, and the mission scenario will determine the scope of interventions suitable to improve outcome. Thus, the profile of requirements for the HEMS medical crew is high.

Comparison of outcomes for children with cervical spine injury based on destination hospital from scene of injury

BACKGROUND

Pediatric cervical spine injury is rare. As a result, evidence-based guidance for prehospital triage of children with suspected cervical spine injuries is limited. The effects of transport time and secondary transfer for specialty care have not previously been examined in the subset of children with cervical spine injuries.

OBJECTIVES

The primary objective was to determine if prehospital destination choice affects outcomes for children with cervical spine injuries. The secondary objectives were to describe prehospital and local hospital interventions for children ultimately transferred to pediatric trauma centers for definitive care of cervical spine injuries.

METHODS

The authors searched the Pediatric Emergency Care Applied Research Network (PECARN) cervical spine injury data set for children transported by emergency medical services (EMS) from scene of injury. Neurologic outcomes in children with cervical spine injuries transported directly to pediatric trauma centers were compared with those transported to local hospitals and later transferred to pediatric trauma centers, adjusting for injury severity, indicated by altered mental status, focal neurologic deficits, and substantial comorbid injuries. In addition, transport times and interventions provided in the prehospital, local hospital, and pediatric trauma center settings were compared. Multiple imputation was used to handle missing data.

RESULTS

The PECARN cervical spine injury cohort contains 364 patients transported from scene of injury by EMS. A total of 321 met our inclusion criteria. Of these, 180 were transported directly to pediatric trauma centers, and 141 were transported to local hospitals and later transferred. After adjustments for injury severity, odds of a normal outcome versus death or persistent neurologic deficit were higher for patients transported directly to pediatric trauma centers (odds ratio [OR] = 1.89, 95% confidence interval [CI] = 1.03 to 3.47). EMS transport times to first hospital did not differ and did not affect outcomes. Prehospital analgesia was very infrequent.

CONCLUSIONS

Initial destination from scene (pediatric trauma center vs. local hospital) appears to be associated with neurologic outcome of children with cervical spine injuries. Markers of injury severity (altered mental status and focal neurologic findings) are important predictors of poor outcome in children with cervical spine injuries and should remain the primary guide for prehospital triage to designated trauma centers.

An investigation of pilot fatigue in helicopter emergency medical services

Pilot error has caused the majority of helicopter emergency medical services (HEMS) accidents in the United States for almost 2 decades. Pilot fatigue may have contributed to some of these accidents. This nonexperimental quantitative study investigated the relationships between fatigue reported by on-duty HEMS pilots (the criterion variable) and consecutive HEMS pilot day shifts, consecutive HEMS pilot night shifts, age, and experience as an HEMS pilot (the predictor variables). Surveys completed by 395 on-duty HEMS pilots in the US were examined to quantify respondent fatigue with the Brief Fatigue Inventory (BFI). This study found some evidence of a statistically significant positive relationship between HEMS pilot night shift respondent BFI scores and experience as an HEMS pilot, while controlling for consecutive HEMS pilot night shifts and age. A 1-way analysis of variance suggested that the effect of experience as an HEMS pilot on HEMS pilot night shift respondent BFI scores was statistically significant. Multivariate regression analysis suggested that experience as an HEMS pilot predicted HEMS pilot night shift respondent BFI scores. Additional quantitative research is recommended to confirm the results of this study and to investigate relationships between fatigue experienced by HEMS pilots and other variables that were not considered in this investigation. Qualitative research to identify and document fatigue management strategies that are used by experience HEMS pilots is also recommended.

Does helicopter transport impact outcome following trauma?

Helicopter transport (HT) has evolved from military roots into a critical component of trauma systems throughout the world. Concerns over cost and safety continue to challenge the role of HT in the civilian setting. Despite this, recent evidence has demonstrated a survival advantage for trauma patients undergoing HT. For patients transported from the scene of injury, improved survival has been shown in several multicenter studies as well as evaluation of large national databases. Issues of overtriage, however, remain problematic for scene HT and represent a prime area for future research in helicopter emergency medical systems (EMS). Patients undergoing inter-facility transfer have also been shown to have improved outcomes over ground transport in terms of shorter transfer times and increased survival particularly in more severely injured patients. The benefits seen are likely a result of a combination of rapid transport, advanced medical capabilities, and accessibility to remote terrain. Several subgroups of patients undergoing HT have been the subject of study as well. Patients with severe head injury have consistently been shown to have superior outcomes over ground ambulance, attributable to improvements in airway management early in the course of their injury. Conversely, HT for urban and penetrating injury has not seen similar benefits, likely due to proximity of trauma centers and recent advancements in urban EMS systems. The benefits of including physicians in helicopter crews are less clear and vary by region and system. Helicopter transport for trauma does appear to improve outcomes for trauma patients, and optimizing utilization of this valuable resource will be key as the role of helicopter EMS continues to develop within trauma systems.

Interfacility transfer of pediatric trauma patients by helicopter does not predict the need for urgent intervention

OBJECTIVES

Helicopter transport can allow trauma patients to reach definitive treatment rapidly, but its appropriate utilization for interfacility transfer to a pediatric trauma center (PTC) has not been well evaluated. This study evaluated differences in variables associated with transport type and intervention at a PTC between helicopter and ground transport for interfacility trauma transfers.

METHODS

This retrospective study evaluated pediatric (<18 years old) trauma patients transferred to a rural PTC over a 5-year period. Records (n = 423) were evaluated for transport type, injuries, mechanism, interventions (eg, operations, transfusions, intubation), and treatment time points. Multiple logistic regression and Cox regression survival analyses were performed to evaluate associations with type of transport and interventions.

RESULTS

Thirty-five percent of patients received intervention at the PTC, with no significant difference between transport types. Helicopter transport was associated with transport distance, respiratory rate greater than 30 breaths/min, pedestrian struck by auto, subdural hematoma, epidural hematoma, pneumothorax, solid organ injury, and vascular compromise/open fracture. Intervention was associated with epidural hematoma, extremity and pelvic fractures, vascular compromise/open fracture, penetrating neck/trunk injury, and complex laceration. Cox regression at less than 6, less than 4, and less than 2 hours after arrival at the PTC demonstrated similar intervention associations. Helicopter transport also correlated with intervention at these time points.

CONCLUSIONS

Most pediatric trauma patients transferred by helicopter did not require interventions. Epidural hematoma, vascular compromise/open fracture, and penetrating neck/trunk injuries predicted prompt interventions (<2 hours) and may have benefited from helicopter transport. There was a disparity between the perceived need for rapid transport and the need for urgent interventions.

Impact of a physician-staffed helicopter on a regional trauma system: a prospective, controlled, observational study

INTRODUCTION

This study aims to compare the trauma system before and after implementing a physician-staffed helicopter emergency medical service (PS-HEMS). Our hypothesis was that PS-HEMS would reduce time from injury to definitive care for severely injured patients.

METHODS

This was a prospective, controlled, observational study, involving seven local hospitals and one level I trauma centre using a before and after design. All patients treated by a trauma team within a 5-month period (1 December 2009-30 April 2010) prior to and a 12-month period (1 May 2010-30 April 2011) after implementing a PS-HEMS were included. We compared time from dispatch of the first ground ambulance to arrival in the trauma centre for patients with Injury Severity Score (ISS) > 15. Secondary end points were the proportion of secondary transfers and 30-day mortality.

RESULTS

We included 1788 patients, of which 204 had an ISS > 15. The PS-HEMS transported 44 severely injured directly to the trauma centre resulting in a reduction of secondary transfers from 50% before to 34% after implementation (P = 0.04). Median delay for definitive care for severely injured patients was 218 min before and 90 min after implementation (P < 0.01). The 30-day mortality was reduced from 29% (16/56) before to 14% (21/147) after PS-HEMS (P = 0.02). Logistic regression showed PS-HEMS had an odds ratio (OR) for survival of 6.9 compared with ground transport.

CONCLUSIONS

Implementation of a PS-HEMS was associated with significant reduction in time to the trauma centre for severely injured patients. We also observed significantly reduced proportions of secondary transfers and 30-day mortality.

Helicopter emergency medical services for adults with major trauma

BACKGROUND

Although helicopters are presently an integral part of trauma systems in most developed nations, previous reviews and studies to date have raised questions about which groups of traumatically injured patients derive the greatest benefit.

OBJECTIVES

The purpose of this review is to determine if helicopter emergency medical services transport (HEMS) is associated with improved morbidity and mortality, compared to ground emergency medical services transport (GEMS), for adults with major trauma. The primary outcome was survival to hospital discharge. Secondary outcomes were quality-adjusted life years (QALYs) and disability-adjusted life years (DALYs).

SEARCH METHODS

Searches were run in CENTRAL, MEDLINE, EMBASE, CINAHL (EBSCOhost), SCI-EXPANDED, CPCI-S, and ZETOC in January 2012. Relevant websites were also searched, including controlled trials registers, HSRProj, the World Health Organization (WHO) ICTRP, and OpenSIGLE. Searches were not restricted by date, language, or publication status. Attempts were made to contact authors in the case of missing data.

SELECTION CRITERIA

Eligible trials included randomised controlled trials (RCTs) and non-randomised intervention studies. Non-randomised studies (NRS), including controlled trials and cohort studies, were also evaluated. Each study was required to have a GEMS comparison group. An injury severity score (ISS) > 15 or an equivalent marker for injury severity was required. Only adults aged 16 years or older were included.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data and assessed the risk of bias of included studies. The Downs and Black quality assessment tool was applied for NRS. The results were analysed in a narrative review, and with studies grouped by methodology and injury type. A predefined subgroup was comprised of four additional studies that examined the role of HEMS versus GEMS for inter-facility transfer. Summary of findings tables were constructed in accordance with the GRADE Working Group criteria.

MAIN RESULTS

Twenty-five studies met the entry criteria for this review. Four additional studies met the criteria for a separate, predefined subgroup analysis of patients transferred to trauma centres by HEMS or GEMS. All studies were non-randomised studies; no RCTs were found. Survival at hospital discharge was the primary outcome. Data from 163,748 people from 21 of the 25 studies included in the primary analysis were available to calculate unadjusted mortality. Overall, considerable heterogeneity was observed and an accurate estimate of overall effect could not be determined. Based on the unadjusted mortality data from five trials that focused on traumatic brain injury, there was no decreased risk of death with HEMS (relative risk (RR) 1.02; 95% CI 0.85 to 1.23). Nine studies used multivariate regression to adjust for confounding, the five largest indicated a statistically significant increased odds of survival associated with HEMS. All Trauma-Related Injury Severity Score (TRISS)-based studies indicated improved survival in the HEMS group as compared to the Major Trauma Outcomes Study (MTOS) cohort; some studies showed survival benefits in both the HEMS and GEMS groups as compared to MTOS. No studies were found to evaluate the secondary outcome of morbidity as assessed by QALYs and DALYs. All four studies suggested a positive benefit when HEMS was used to transfer patients to higher level trauma centres. Overall, the quality of the included studies was very low as assessed by the GRADE Working Group criteria.

AUTHORS' CONCLUSIONS

Due to the methodological weakness of the available literature, and the considerable heterogeneity of effects and study methodologies, an accurate composite estimate of the benefit of HEMS could not be determined. Although five of the nine multivariate regression studies indicated improved survival associated with HEMS, the remainder did not. All were subject to a low quality of evidence as assessed by the GRADE Working Group criteria due to their non-randomised design. Similarly, TRISS-based studies, which all demonstrated improved survival, cannot be considered strong evidence because of their methodology, which did not randomize the use of HEMS. The question of which elements of HEMS may be beneficial for patients has not been fully answered. The results from this review provide motivation for future work in this area. This includes an ongoing need for diligent reporting of research methods, which is imperative for transparency and to maximise the potential utility of results. Large, multicentre studies are warranted as these will help produce more robust estimates of treatment effects. Future work in this area should also examine the costs and safety of HEMS, since multiple contextual determinants must be considered when evaluating the effects of HEMS for adults with major trauma.

Patient safety in emergency medical services: a systematic review of the literature

BACKGROUND

Preventable harm from medical care has been extensively documented in the inpatient setting. Emergency medical services (EMS) providers care for patients in dynamic and challenging environments; prehospital emergency care is a field that represents an area of high risk for errors and harm, but has received relatively little attention in the patient safety literature.

OBJECTIVE

To identify the threats to patient safety unique to the EMS environment and interventions that mitigate those threats, we completed a systematic review of the literature.

METHODS

We searched MEDLINE, EMBASE, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for combinations of key EMS and patient safety terms composed by a pan-canadian expert panel using a year limit of 1999 to 2011. We excluded commentaries, opinions, letters, abstracts, and non-english publications. Two investigators performed an independent hierarchical screening of titles, abstracts, and full-text articles blinded to source. We used the kappa statistic to examine interrater agreement. Any differences were resolved by consensus.

RESULTS

We retrieved 5,959 titles, and 88 publications met the inclusion criteria and were categorized into seven themes: adverse events and medication errors (22 articles), clinical judgment (13), communication (6), ground vehicle safety (9), aircraft safety (6), interfacility transport (16), and intubation (16). Two articles were randomized controlled trials; the remainder were systematic reviews, prospective observational studies, retrospective database/chart reviews, qualitative interviews, or surveys. The kappa statistics for titles, abstracts, and full-text articles were 0.65, 0.79, and 0.87, respectively, for the first search and 0.60, 0.74, and 0.85 for the second.

CONCLUSIONS

We found a paucity of scientific literature exploring patient safety in EMS. Research is needed to improve our understanding of problem magnitude and threats to patient safety and to guide interventions.

Incidents, accidents and fatalities in 40 years of German helicopter emergency medical system operations

CONTEXT

Currently, approximately 100 000 helicopter emergency medical service (HEMS) missions for patients are undertaken in Germany each year. Compared to the early years, risk has reduced significantly, but is still higher than commercial aviation or other airborne operations.

OBJECTIVE

The aim of the present study was to evaluate helicopter accidents and fatalities related to HEMS operations.

DESIGN

Retrospective study of HEMS accidents in Germany.

SETTING

Analysis of accidents in the published flight accident reports of the German Federal Agency for Flight Accident Investigation (40-year period from 1970 to 2009). Data were collected by telephone interview with the operators, manual search of publications and by supplemental internet information.

MAIN OUTCOME MEASURES

Data were analysed per 10 000 missions. For statistical analysis, Fisher[Combining Acute Accent]s exact test was used. A P value less than 0.05 was considered significant.

RESULTS

During the period analysed, a total of 1.698 million HEMS missions (1970 vs. 2009: 61 vs. 98 471) were flown by a mean of 50 ± 27 (1 vs. 81) helicopters. To date, missions resulted in a total of 99 accidents with a mean of 2.4 ± 1.7 accidents per year (range 0-7). The accident rate was 0.57 (0-11.4) per 10 000 missions and the fatal accident rate was 0.11 (0-0.5). Some 64% of missions did not result in any injuries to occupants, whereas 19.2% were fatal. From the accidents analysed, 43.4% were due to collision with an obstacle during landing, take-off or hovering. Landing was the phase of flight most often associated with accidents (44.4%).

CONCLUSION

The present study is the largest on HEMS accidents and the only one analysing an entire 40-year time course beginning with inception. In comparison to previous data, a significantly lower accident rate per 10 000 missions was found. Gathering data on the early years is nearly impossible, and further analysis is required to calculate the risk of fatality or identify injury patterns.

An example of extreme cardiology: chest pain on the high seas and helicoptered medical evacuations: the French Navy experience

Medicalized high sea rescue is very different from prehospital medical evacuation. It requires specifically trained medical teams because the difficulties are marine, aerial, and medically related. The French Navy provides medical evacuations by helicopter on the Atlantic coast, up to 320 km offshore and under all weather conditions. The epidemiology of acute chest pain in the high seas has been poorly described. Therefore, in this retrospective study, we aimed to assess the prevalence and constraints found in the management of these emergencies. From January 1, 2000, to April 30, 2009, 286 medical evacuations by helicopter were performed, 132 of which were due to traumatological emergencies, and 154 to medical emergencies. Acute chest pain, with 36 missions, was the leading cause of medical evacuation. All evacuated patients were men who were either professional sailors or ferry passengers. The median age was 48 years (range, 26-79). The most common prehospital diagnosis was coronary chest pain in 23 patients (64%), including 11 patients with acute coronary syndrome with ST-segment elevation. Thirty-two patients were airlifted by helicopter. All patients benefited from monitoring, electrocardiogram, peripheral venous catheter, and medical management as soon as the technical conditions allowed it.

Helicopters improve survival in seriously injured patients requiring interfacility transfer for definitive care

BACKGROUND

Helicopter transport (HT) is frequently used for interfacility transfer of injured patients to a trauma center. The benefits of HT over ground transport (GT) in this setting are unclear. By using a national sample, the objective of this study was to assess whether HT impacted outcomes following interfacility transfer of trauma patients.

METHODS

Patients transferred by HT or GT in 2007 were identified using the National Trauma Databank (version 8). Injury severity, resource utilization, and survival to discharge were compared. Stepwise logistic regression was used to determine whether transport modality was a predictor of survival after adjusting for covariates. Regression analysis was repeated in subgroups with Injury Severity Score (ISS)≤15 and ISS>15.

RESULTS

There were 74,779 patients transported by helicopter (20%) or ground (80%). Mean ISS was higher in patients transported by helicopter (17±11 vs. 12±9; p<0.01) as was the proportion with ISS>15 (49% vs. 28%; odds ratio [OR], 2.53; 95% confidence interval [CI], 2.43-2.63). Patients transported by helicopter had higher rates of intensive care unit admission (54% vs. 29%; OR, 2.86; 95% CI, 2.75-2.96), had shorter transport time (61±55 minutes vs. 98±71 minutes; p<0.01), and had shorter overall prehospital time (135±86 minutes vs. 202±132 minutes; p<0.01). HT was not a predictor of survival overall or in patients with ISS≤15. In patients with ISS>15, HT was a predictor of survival (OR, 1.09; 95% CI, 1.02-1.17; p=0.01).

CONCLUSIONS

Patients transported by helicopter were more severely injured and required more hospital resources than patients transported by ground. HT offered shorter transport and overall prehospital times. For patients with ISS>15, HT was a predictor of survival. These findings should be considered when developing interfacility transfer policies for patients with severe injuries.

Factors at the scene of injury associated with air versus ground transport to definitive care in a state with a large rural population

BACKGROUND

Once emergency medical services (EMS) personnel decide to transport a trauma patient directly to definitive care, the next key decision at the scene of injury is whether to transport by air or ground.

OBJECTIVE

The aim of this study was to identify factors at the scene of injury that are associated with this decision.

METHODS

All trauma patients transported directly to a level I or level II trauma center by either air or ground EMS over a four-year period were selected from the Oklahoma State Trauma Registry. Initial scene vital signs, Glasgow Coma Scale score (GCS), injury mechanism, anatomic triage criteria, age, time of day, ground EMS service level, and scene location were collected. Scene location ZIP code centroids were geocoded and used to calculate distance to the trauma center. Following bivariate analyses, multivariable logistic regression models were developed within three strata defined by distance (>35, 16-35, and <16 miles).

RESULTS

More than 80% of the patients beyond 35 miles were transported by air, compared with 32% from 16-35 miles and only 4% from <16 miles. Regardless of distance, patients transported by helicopter tended to be younger, more often had abnormal vital signs, and more frequently came from areas served by a basic or intermediate ground EMS agency, as compared with patients transported by ground. Within each distance stratum, patients injured in severe motor vehicle crashes, motorcycle crashes, or pedestrian incidents were more likely to be transported by air. A GCS <14 was the only patient-related factor consistently associated with increased odds of air transport.

CONCLUSION

Distance is the main factor in deciding whether to use air or ground EMS to transport a trauma patient from the scene of injury to a trauma center. With the exception of GCS <14, injury etiology was more strongly and consistently associated with the decision to transport by air than were patient related-factors. Identifying factors influencing the field transport decision will help develop transport guidelines that make efficient use of EMS resources.

Helicopter evacuation of trauma victims in Los Angeles: does it improve survival?

BACKGROUND

The purpose of this study was to investigate the relationship between the method of transport after injury and survival among trauma patients admitted to a Level 1 trauma facility in Los Angeles, California.

METHODS

The trauma registry of LAC+USC Medical Center was reviewed to identify all injured patients evacuated by emergency medical service (EMS) from the injury scene from 1998 to 2007. The study population was divided into those who were airlifted (HEMS) and those who were transported by ground emergency medical service (GEMS) with transportation time that exceeded 30 minutes (GEMS > 30 minutes).

RESULTS

During the 10-year study period, 1,836 patients were airlifted (helicopters for emergency medical service (HEMS)) and 1,537 patients were ground transported (GEMS > 30 minutes). HEMS patients suffered more frequently a penetrating injury (19% vs. 11%, p < 0.001), presented more often hypotensive to the emergency department (4% vs. 1%, p < 0.001), had more frequently a Glasgow Coma Scale (GCS) < or = 8 (9% vs. 3%, p < 0.001) and required more often an intubation at the injury scene (1.6% vs. 0.4%, p < 0.001). However, the transportation time and the total prehospital time were significantly shorter for airlifted patients. After multivariable analysis, the difference in mortality between the two transport modalities was not significant (adjusted odds ratio (95% confidence interval, 0.72 (0.22, 2.35); p = 0.596).

CONCLUSIONS

In a metropolitan Los Angeles trauma system, EMS helicopter transportation of injured patients does not appear to improve overall adjusted survival after injury. There is however a potential benefit for severely injured subgroups of patients due to the shorter prehospital times.

The riskiest job in medicine: transplant surgeons and organ procurement travel

Transplant surgeons are exposed to workplace risk due to the urgent nature of travel related to organ procurement. A retrospective cohort study was completed using data from the Scientific Registry of Transplant Recipients and the National Transportation Safety Board. A web-based survey was administered to members of the American Society of Transplant Surgeons. The survey response rate was 38% (281/747). Involvement in > or =1 procurement-related travel accident was reported by 15% of respondents; surgeons reported 61 accidents and 11 fatalities. Air travel was used in 26% of procurements and was involved in 56% of accidents. The risk of fatality while traveling on an organ procurement flight was estimated to be 1000 times higher than scheduled commercial flight. Involvement in a 'near miss accident' was reported by 80.8%. Only 16% of respondents reported feeling 'very safe' while traveling. Procurement of organs by the geographically closest transplant center would have reduced the need for air travel (>100 nautical miles) for lung, heart, liver and pancreas procurement by 35%, 43%, 31% and 49%, respectively (p < 0.0001). These reductions were observed in each Organ Procurement and Transplantation Network region. Though these data have important limitations, they suggest that organ procurement travel is associated with significant risk. Improvements in organ procurement travel are needed.