Nontrauma helicopter emergency medical services transport: annotated review of selected outcomes-related literature

Natural Experiment Outcomes Studies in Rotor Wing Air Medical Transport: Systematic Review and Meta-Analysis of Before-and-After and Helicopter-Unavailable Publications From 1970 to 2022

OBJECTIVE

Helicopter emergency medical services (HEMS) is widely used for prehospital and interfacility transport, but there is a paucity of HEMS outcomes data from studies using randomized controlled trial designs. In the absence of robust randomized controlled trial evidence, judgments regarding HEMS potential benefit must be informed by observational data. Within the study design set of observational analyses, the natural experiment (NE) is notable for its high potential methodologic quality; NE designs are occasionally denoted "quasi-experimental." The aim of this study is to examine all NE outcomes studies in the HEMS literature and to discern what lessons can be learned from these potentially high-quality observational data.

METHODS

HEMS NE studies were identified during the development of a new HEMS Outcomes Assessment Research Database (HOARD). HOARD was constructed using a broad-ranging search of published and gray literature resources (eg, PubMed, Embase, and Google Scholar) that used variations of the terms "helicopter EMS," "air ambulance," and "air medical transport." Among the 221 studies ultimately included in HOARD, 16 NE publications describing 13 sets of observational data comprising myriad diagnostic groups were identified. Of these 16 HEMS NEs, 4 HEMS NE studies assessing trauma outcomes were used in a meta-analysis. A meta-analysis was also performed of 4 HEMS NE studies.

RESULTS

Although the disparity of studies (in terms of both case mix and end points) precluded the generation of a pooled effect estimate of an adjusted mortality benefit of HEMs versus ground emergency medical services, HEMS was found to be associated with outcomes improvement in 8 of the 13 cohorts.

CONCLUSION

The weight of the NE evidence supports a conclusion of some form of HEMS-mediated outcomes improvement in a variety of patient types. Meta-analysis of 4 HEMS NE studies assessing trauma outcomes generated a model with acceptable heterogeneity (I2 = 43%, Q test: P = .16), which significantly (P < .01) favored HEMS use with a pooled HEMS survival odd ratio estimate of 1.66 (95% confidence interval, 1.23-2.22).

Helicopter Emergency Medical Services Outcomes Research 1983 to 2022: Evidence Overview and Longitudinal Trends

OBJECTIVE

Helicopter emergency medical services (HEMS) literature has been assessed in reviews focusing on various diagnoses, but there are few, if any, summaries of the entire body of HEMS outcomes evidence. Our goal was to summarize the existing research addressing patient-centered outcomes potentially accrued with HEMS.

METHODS

As part of the Critical Care Transport Collaborative Outcomes Research Effort, we generated the HEMS Outcomes Assessment Research Database and executed descriptive analyses of longitudinal trends from 1983 to 2022. Both indexed and gray literature sources were incorporated in the HEMS Outcomes Assessment Research Database. Studies were reviewed by at least 2 authors to select those that addressed a patient-centered outcome. Studies addressing solely HEMS logistics were excluded. Categoric analyses were executed with the Fisher exact test, and continuous variables were evaluated for normality with normal quantile plotting and a comparison of medians and 95% confidence intervals.

RESULTS

We found that HEMS outcomes study sample sizes increased steadily from 1983 to 2012, with the most recent decade demonstrating a marked increase in the rate of publication of HEMS outcomes studies. Most research (70.6%) addressed trauma patient outcomes, but recent decades have seen a significant increase in non-trauma studies. Recent decades have also been characterized by an increase in the production of HEMS outcomes research outside of North America and Europe.

CONCLUSION

This study summarizes the current state of the HEMS outcome literature. We highlight increasing contributions from worldwide researchers and increasing focus on HEMS benefits in non-trauma cases, particularly time-critical cases such as cardiac or stroke diagnoses. This provides a basis for further investigations into patient-oriented benefits potentially accrued with HEMS.

Value Utilization of Emergency Medical Services Air Transport in Acute Ischemic Stroke

BACKGROUND

Determining whether a patient has a time-critical medical condition requiring helicopter Emergency Medical Services (HEMS) transportation is a challenge with acute ischemic stroke (AIS). Although HEMS is largely accepted as improving outcomes in time-sensitive conditions, overtriage of patients ineligible for acute stroke therapies places patients and providers at unnecessary risk and wastes limited health care resources.

OBJECTIVE

We sought to identify how accurate our triage system was at identifying high-yield EMS transfers. A better triage system would decrease the volume of low flight value HEMS transfers.

METHODS

We conducted a retrospective study during a 1-year period. Low flight value was defined by acute therapy eligibility and presenting medical status.

RESULTS

Of 141 AIS patients transferred by HEMS, 23 (16%) were deemed of low flight value; 14 (61%) were outside the acute treatment time window for either intravenous tissue plasminogen activator or endovascular therapy (EVT); 5 patients (22%) were ineligible for EVT (National Institute of Health Stroke Scale < 6); 2 patients (9%) were ineligible for EVT (Modified Rankin Scale ≥ 3); and 2 patients (9%) were flown despite negative angiographic studies performed at transferring institution. Thirteen (57%) of the patients were interfacility transfers as opposed to direct HEMS transport from the field.

CONCLUSIONS

HEMS transport for AIS patients plays a crucial role in delivering the best evidence-based care. However, a significant percent of patients did not meet criteria for its optimal utilization, most commonly due to expired treatment windows. Furthermore, low flight value transfers were initiated in spite of physician evaluation > 50% of the time. These results represent a unique opportunity to coordinate education and build effective triage paradigms across a system of stroke care.

Helicopter Emergency Medical Services Literature 1972-2017: Characteristics and Trends

Since its inception in the latter part of the 20th century, the rapid expansion of helicopter emergency medical services (HEMS) has been accompanied by remarkable growth in the relevant evidence base. There are many review articles describing lessons contained within the various arenas of HEMS literature, but there is little or no characterization of the numbers and types of publications comprising the HEMS-related evidence base. This study analyzed all indexed publications mentioning HEMS (with abstract included) in the United States National Library of Medicine's PubMed collection. The aims of the analysis were to provide quantitative, qualitative, and longitudinal trend information regarding the 1972 to 2017 evidence base relevant to HEMS.

Helicopter patient transportation service on the Ulleung Island, South Korea

INTRODUCTION

Despite numerous studies of helicopter emergency medical services, few reports have examined the outcomes of patients transported by helicopter across the sea from isolated islands. We analyzed helicopter transportation from the isolated Ulleung Island, which lies to the east of the South Korean mainland.

METHODS

This study included 284 patients transported from the Ulleung Island to mainland hospitals between January 2007 and March 2013. Emergency Severity Index and Injury Severity Score were calculated. Hospital stay time and flight duration was measured. Data were analyzed using Student's t-test.

RESULTS

The mean age of the patients was 53.5 years. Of the transported patients, 19.0% were visitors to the island and 29.6% were traumatically injured. The mortality rate after transportation was 11.6% (33 patients).

CONCLUSION

Helicopter transportation has been very beneficial for the treatment of emergency patients on Ulleung Island. A national level of interest and investment is required to improve this service.

Ten years of helicopter emergency medical services in Germany: do we still need the helicopter rescue in multiple traumatised patients?

BACKGROUND

Helicopter emergency medical service (HEMS) has been established in the preclinical treatment of multiple traumatised patients despite an ongoing controversy towards the potential benefit. Celebrating the 20th anniversary of TraumaRegister DGU(®) of the German Trauma Society (DGU) the presented study intended to provide an overview of HEMS rescue in Germany over the last 10 years analysing the potential beneficial impact of a nationwide helicopter rescue in multiple traumatised patients.

PATIENTS AND METHODS

We analysed TraumaRegister DGU(®) including multiple traumatised patients (ISS ≥ 16) between 2002 and 2012. In-hospital mortality was defined as main outcome. An adjusted, multivariate regression with 13 confounders was performed to evaluate the potential survival benefit.

RESULTS

42,788 patients were included in the present study. 14,275 (33.4%) patients were rescued by HEMS and 28,513 (66.6%) by GEMS. Overall, 66.8% (n=28,569) patients were transported to a level I trauma centre and 28.2% (n=12,052) to a level II trauma centre. Patients rescued by HEMS sustained a higher injury severity compared to GEMS (ISS HEMS: 29.5 ± 12.6 vs.

ISS GEMS

27.5 ± 11.8). Helicopter rescue teams performed more on-scene interventions, and mission times were increased in HEMS rescue (HEMS: 77.2 ± 28.7 min. vs. GEMS: 60.9 ± 26.9 min.). Linear regression analysis revealed that the frequency of HEMS rescue has decreased significantly between 2002 and 2012. In case of transportation to level I trauma centres a decrease of 1.7% per year was noted (p<0.001) while a decline of 1.6% per year (p<0.001) was measured for level II trauma centre admissions. According to multivariate logistic regression HEMS was proven a positive independent survival predictor between 2002 and 2012 (OR 0.863; 95%-CI 0.800-0.930; Nagelkerkes-R(2) 0.539) with only little differences between each year.

CONCLUSIONS

This study was able to prove an independent survival benefit of HEMS in multiple traumatised patients during the last 10 years. Despite this fact, a constant decline of HEMS rescue missions was found in multiple trauma patients due to unknown reasons. We concluded that HEMS should be used more often in case of trauma in order to guarantee the proven benefit for multiple traumatised patients.

Helicopter transport effectiveness of patients for primary percutaneous coronary intervention

BACKGROUND

For patients with ST-elevated myocardial infarction (STEMI), time to primary percutaneous coronary intervention (PCI) is an important factor in saving myocardium. Helicopter emergency medical service (HEMS) has become a vital component in regionalized cardiac care. The objective of this study is to assess the logistics of HEMS and ground EMS for interfacility transport of STEMI patients for primary PCI and to determine the effectiveness of HEMS transports in terms of the number of lives saved per 100 flights.

METHODS

This is a retrospective database and records review of interfacility transports of STEMI patients for primary PCI to a single medical center. The study period consisted of 18 months (January 2010 through June 2011).

RESULTS

Ninety-seven of 120 patients met the criteria for review. Of these, 66% were transported by HEMS. The pretransport patient handling times were similar for the HEMS and ground EMS groups. Door-to-PCI in < 120 minutes was achieved in 35.5% (11 of 31) of ground EMS and 24.2% (16 of 66) of HEMS. Patients transported by ground EMS were more likely to get to PCI in < 90 minutes (9.7%, 3 of 31). HEMS patients traveled significantly farther distances, 51 miles (IQR 43-68) than ground EMS, 37 miles (IQR 18-51). This equates to a 38% longer distance for patients transported by HEMS. An estimate of the driving time for HEMS-transported patients suggests HEMS transports saved a median of 41 minutes (IQR 33-48). The proportion of HEMS flights saving more than 30 minutes was 78.8% (95% CI 67.0-87.9%).

CONCLUSION

The results did not show a time savings for HEMS- versus ground EMS-transported patients. When estimates of time spent for ground EMS of actual HEMS transported patients are analyzed, HEMS provides a median savings of 41 minutes, with a savings of at least 30 minutes in 78.8% of the HEMS patients. Based on estimates used in this study, conservative calculations arrived at a time-based mortality effectiveness of HEMS of about 1.2 lives saved per 100 flights.

The cost-effectiveness of physician staffed Helicopter Emergency Medical Service (HEMS) transport to a major trauma centre in NSW, Australia

BACKGROUND AND CONTEXT

Helicopter Emergency Medical Services (HEMS) are highly resource-intensive facilities that are well established as part of trauma systems in many high-income countries. We evaluated the cost-effectiveness of a physician-staffed HEMS intervention in combination with treatment at a major trauma centre versus ground ambulance or indirect transport (via a referral hospital) in New South Wales (NSW), Australia.

METHODS

Cost and effectiveness estimates were derived from a cohort of trauma patients arriving at St George Hospital in NSW, Australia during an 11-year period. Adjusted estimates of in-hospital mortality were derived using logistic regression and adjusted hospital costs were estimated through a general linear model incorporating a gamma distribution and log link. These estimates along with other assumptions were incorporated into a Markov model with an annual cycle length to estimate a cost per life saved and a cost per life-year saved at one year and over a patient's lifetime respectively in three patient groups (all patients; patients with serious injury [Injury Severity Score>12]; patients with traumatic brain injury [TBI]).

RESULTS

Results showed HEMS to be more costly but more effective at reducing in-hospital mortality leading to a cost per life saved of $1,566,379, $533,781 and $519,787 in all patients, patients with serious injury and patients with TBI respectively. When modelled over a patient's lifetime, the improved mortality associated with HEMS led to a cost per life year saved of $96,524, $50,035 and $49,159 in the three patient groups respectively. Sensitivity analyses revealed a higher probability of HEMS being cost-effective in patients with serious injury and TBI.

CONCLUSION

Our investigation confirms a HEMS intervention is associated with improved mortality in trauma patients, especially in patients with serious injury and TBI. The improved benefit of HEMS in patients with serious injury and TBI leads to improved estimated cost-effectiveness.

Helicopter EMS Transport Outcomes Literature: Annotated Review of Articles Published 2007-2011

Helicopter EMS (HEMS) and its possible association with outcomes improvement continues to be a subject of discussion. As is the case with other scientific discourse, debate over HEMS usefulness should be framed around an evidence-based assessment of the relevant literature. In an effort to facilitate the academic pursuit of assessment of HEMS utility, in late 2000 the National Association of EMS Physicians' (NAEMSP) Air Medical Task Force prepared annotated bibliographies of the HEMS-related outcomes literature. As a result of that work, two review articles, one covering HEMS use in nontrauma and the other in trauma, published in 2002 in Prehospital Emergency Care surveyed HEMS outcomes-related literature published between 1980 and mid-2000. The project was extended with two subsequent reviews covering the literature through 2006. This review continues the series, outlining outcomes-associated HEMS literature for the three-year period 2007 through the first half of 2011.

A systematic review of the costs and benefits of helicopter emergency medical services

INTRODUCTION

Helicopter emergency medical services (HEMS) are popular in first world health systems despite inconsistent evidence in the scientific literature to support their use. The aim of the current study was to perform a systematic review of economic evaluations of HEMS, in order to determine the economic cost of HEMS and the associated patient-centered benefits.

METHOD

A systematic review was performed of studies that provided a cost estimate of HEMS. The inclusion criteria consisted of English language articles that estimated both the costs and outcomes of a HEMS and fulfilled pre-specified criteria in relation to a cost analysis, cost-minimisation, cost-effectiveness or cost-benefit evaluation. Identified studies were synthesised according to the patient diagnosis (trauma, non-trauma or non-specific) and the type of HEMS transport under review (primary scene retrieval or secondary inter-facility transport). All costs were converted to US dollars and indexed for inflation.

RESULTS

Fifteen studies met the inclusion criteria. Among all studies the annual cost of HEMS ranged from $115,777 to $5,571,578. Five studies showed HEMS to be a more expensive transport alternative without an associated benefit while eight studies provided cost-effectiveness ratios of $3292 and $2227 per life year saved for trauma, $3258 per life saved and $7138 and $12,022 per quality adjusted life year for non-trauma and $30,365 and $91,478 per beneficial mission for non-specific patient populations. One study also evaluated the cost of HEMS to societal benefit, producing a ratio of 1:6.

INTERPRETATION

The cost and effectiveness of HEMS varied considerably between studies. Despite generally being more expensive than ground transport, a number of studies found HEMS to be cost-effective. However, given the variation in the intervention design, context and study methods between studies it was not possible to assess the cost-effectiveness of HEMS in general. Given the variation inherent in the health systems in which HEMS operate, synthesis and extrapolation of study findings across differing health environments is difficult. To address economic and clinical evidence in relation to HEMS, future research that is tailored to account for local system factors is required.

Helicopter EMS Transport Outcomes Literature: Annotated Review of Articles Published 2004-2006

Helicopter EMS (HEMS) and its possible association with outcomes improvement continues to be a subject of debate. As is the case with other scientific endeavors, debate over HEMS usefulness should be framed around an evidence-based assessment of the relevant literature. In an effort to facilitate the academic pursuit of assessment of HEMS utility, in late 2000 the National Association of EMS Physicians' (NAEMSP) Air Medical Task Force prepared annotated bibliographies of the HEMS-related outcomes literature. As a result of that work, two review articles, one covering HEMS use in nontrauma and the other in trauma, published in 2002 in Prehospital Emergency Care surveyed HEMS outcomes-related literature published between 1980 and mid-2000. The project was extended with a 2004 review that covered the literature published between 2000 and 2003. The current review continues the series, outlining outcomes-associated HEMS literature from 2004 through 2006.

Medically appropriate use of helicopter EMS: the mission acceptance/triage process

INTRODUCTION

Appropriate use of helicopter emergency medical services (HEMS) ensures the maximum impact of a limited resource on improved health outcomes. Overtriage increases real and opportunity costs and may unjustifiably expose the program to small but inherent safety risks. The purpose of this study is to describe the mission acceptance process for an integrated, provincially based HEMS program and determine its utilization patterns.

METHODS

This is a retrospective review of patient care and administrative databases. All missions were reviewed to determine whether they were medically appropriate. "Appropriateness" was defined a priori as requiring admission to a critical care unit, death during transportation or in first 24 hours, or in the case of trauma, an injury severity scale (ISS) score > or = 12. Overtriage was defined as not meeting these a priori definitions.

RESULTS

Five hundred eighty-four missions were reviewed from March 31, 2003 through December 31, 2004. Our mission acceptance process consists of three distinct but complementary phases: ongoing outreach education, scanning by dispatchers in an integrated dispatch center, and a clinician to online physician discussion about each case. The overall overtriage rate was 13.1%.

CONCLUSION

The rate of medically appropriate missions in this system is relatively high. Prospective research is required to improve HEMS triage systems.

The 2003 Air Medical Leadership Congress: findings and recommendations

To address important concerns facing the air medical community, 149 air medical transport leaders, providers, consultants, and experts met September 4-6, 2003, in Salt Lake City, Utah, for a 3-day summit-the Air Medical Leadership Congress: Setting the Health Care Agenda for the Air Medical Community. Using data from a Web-based survey, top air medical transport issues were identified in four core areas: safety, medical care, cost/benefit, and regulatory/compliance. This report reviews the findings of previous congresses and summarizes the discussions, findings, recommendations, and proposed industry actions to address these issues as set forth by the 2003 congress participants.