Outcomes after cancelled helicopter emergency medical service missions due to concurrencies: a retrospective cohort study

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).

Can video communication in the emergency medical communication centre improve dispatch precision? A before-after study in Norwegian helicopter emergency medical services

OBJECTIVES

Dispatching helicopter emergency medical services (HEMS) to the patients with the greatest medical or logistical benefit remains challenging. The introduction of video calls (VC) in the emergency medical communication centres (EMCC) could provide additional information for EMCC operators and HEMS physicians when assessing the need for HEMS dispatch. The aim of this study was to evaluate the impact from VC in the EMCC on HEMS dispatch precision.

DESIGN

An observational before-after study.

SETTING

The regional EMCC and one HEMS base in Mid-Norway.

PARTICIPANTS

EMCC operators and HEMS physicians at the EMCC and HEMS base in Trondheim, Norway.

INTERVENTION

In January 2022, VC became available in emergency calls in Trondheim EMCC. Data were collected from 2020 2021 (pre-intervention) and 2022 (post-intervention).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the proportion of seriously ill or injured HEMS patients, defined as a National Advisory Committee for Aeronautics (NACA) score between 4 and 7. The secondary outcome was the proportion of inappropriate dispatches, defined as missions with neither provision of additional competence nor any logistical contribution based on quality indicators for physician-staffed emergency medical services.

RESULTS

811 and 402 HEMS missions with patient contact were included in the pre- and post-intervention group, respectively. The proportion of missions with NACA 4-7 was not significantly changed after the intervention (OR 1.21, 95% CI 0.92 to 1.61, p=0.17). There was no significant change in HEMS alarm times between the pre- and post-intervention groups (7.6 min vs 6.4 min, p=0.15). The proportion of missions with neither medical nor logistical benefit was significantly lower in the post-intervention group (28.4% vs 40.3%, p=0.007).

CONCLUSION

The results from this study indicate that VC is a promising, feasible and safe tool for EMCC operators in the complex HEMS dispatch process.

The introduction of a regional Norwegian HEMS coordinator: an assessment of the effects on response times, geographical service areas and severity scores

Background

Due to unwanted delays and suboptimal resource control of helicopter emergency medical services (HEMS), regional HEMS coordinators have recently been introduced in Norway. This may represent an unnecessary link in the alarm chain, which could cause delays in HEMS dispatch. Systematic evaluations of this intervention are lacking. We wanted to conduct this study to assess possible changes in HEMS response times, mission distribution patterns and patient characteristics within our region following this intervention.

Methods

We retrospectively collected timeline parameters, patient characteristics and GPS positions from HEMS missions executed by three regional HEMS bases in Mid-Norway during 2017–2018 (preintervention) and 2019 (postintervention). The mean regional response time in HEMS missions was assessed by an interrupted time series analysis (ITS). The geographical mission distribution between regional HEMS resources was assessed by a before-after study with a convex hull-based method.

Results

There was no significant change in the level (-0.13 min/month, p = 0.88) or slope (-0.13 min/month, p = 0.30) of the mean regional response time trend line pre- and postintervention. For one HEMS base, the service area was increased, and the median mission distance was significantly longer. For the two other bases, the service areas were reduced. Both the mean NACA score (4.13 ± SD 0.027 vs 3.98 ± SD 0.04, p < 0.01) and the proportion of patients with severe illness or injury (NACA 4–7, 68.2% vs 61.5%, p < 0.001) were higher in the postintervention group.

Conclusion

The introduction of a regional HEMS coordinator in Mid-Norway did not cause prolonged response times in acute HEMS missions during the first year after implementation. Higher NACA scores in the patients treated postintervention suggest better selection of HEMS use.

Mortality and hospitalisation in the Danish Helicopter Emergency Medical Service (HEMS) population from 2014 to 2018: a national population-based study of HEMS triage

OBJECTIVE

To describe characteristics and outcomes for patients where the Danish Helicopter Emergency Medical Service (HEMS) either transported the patient to hospital, treated the patient on scene but did not transport the patient or was dispatched but cancelled en route to the patient (aborted mission), and to assess the field triage by comparing these outcomes.

DESIGN

National population-based study.

SETTING AND PARTICIPANTS

HEMS dispatches are undertaken from the five Danish emergency dispatch medical centres according to national guidelines. The study analysed all primary missions with helicopter take off where the patient was admitted to hospital between 1^st October 2014 and 30^th April 2018.

MAIN OUTCOME MEASURES

Mortality rates, admittance to an intensive care unit (ICU), need of mechanical ventilation and length of hospital stay (LOS).

RESULTS

6931 patients were admitted to hospital; 3311 patients were air lifted, 164 patients were ground escorted by a HEMS physician, 1421 were assisted on scene by HEMS, but escorted by the ground units and 2035 missions were aborted. The mortality was highest among the airlifted and ground escorted patients, and lowest among the patients in the aborted mission group. Mortality for the airlifted patients increased from 8.2% (95% CI; 7.3 to 9.2) at day 1 to 19.5% (95% CI; 18.2 to 20.9) after 1 year. The airlifted and ground escorted patients were frequently admitted to ICU and subsequently mechanically ventilated and they also had an increased LOS compared with the patients only assisted on scene by HEMS and the patients in the aborted mission group.

CONCLUSION

Patients to whom HEMS are dispatched are often critically ill or injured and have a relatively high mortality. The patients airlifted or ground escorted to hospital by HEMS appear more critically ill or injured compared with the assisted patients and the patients in the aborted mission group. The on-scene triage seems appropriate.

A prospective observational study of why people are medically evacuated from offshore installations in the North Sea

OBJECTIVES

Few studies have described evacuations due to medical emergencies from the offshore installations in the North Sea, though efficient medical service is essential for the industrial activities in this area. The major oil- and gas-producing companies' search and rescue (SAR) service is responsible for medical evacuations. Using a prospective approach, we describe the characteristics of patients evacuated by SAR.

DESIGN AND SETTING

A prospective observational study of the offshore primary care provided by SAR in the North Sea.

METHODS

Patients were identified by linking flight information from air transport services in 2015/2016 and the company's medical record system. Standardised forms filled out by SAR nurses during the evacuation were also analysed. In-hospital information was obtained retrospectively from Haukeland University Hospital's information system.

RESULTS

A total of 381 persons (88% men) were evacuated during the study period. Twenty-seven per cent of missions were due to chest pain and 18% due to trauma. The mean age was 46.0 years. Severity scores were higher for cases due to medical conditions compared with trauma, but the scores were relatively low compared with onshore emergency missions. The busiest months were May, July and December. Weekends were the busiest days.

CONCLUSION

Three times as many evacuations from offshore installations are performed due to acute illness than trauma, and cardiac problems are the most common. Although most patients are not severely physiologically deranged, the study documents a need for competent SAR services 24 hours a day year-round. Training and certification should be tailored for the SAR service, as the offshore health service structure and geography differs from the structure onshore.

Limitation of treatment in prehospital care - the experiences of helicopter emergency medical service physicians in a nationwide multicentre survey

Background

Making ethically sound treatment limitations in prehospital care is a complex topic. Helicopter Emergency Medical Service (HEMS) physicians were surveyed on their experiences with limitations of care orders in the prehospital setting, including situations where they are dispatched to healthcare facilities or nursing homes.

Methods

A nationwide multicentre study was conducted among all HEMS physicians in Finland in 2017 using a questionnaire with closed five-point Likert-scale questions and open questions. The Ethics Committee of the Tampere University Hospital approved the study protocol (R15048).

Results

Fifty-nine (88%) physicians responded. Their median age was 43 (IQR 38–47) and median medical working experience was 15 (IQR 10–20) years. All respondents made limitation of care orders and 39% made them often. Three fourths (75%) of the physicians were often dispatched to healthcare facilities and nursing homes and the majority (93%) regularly met patients who should have already had a valid limitation of care order. Every other physician (49%) had sometimes decided not to implement a medically justifiable limitation of care order because they wanted to avoid conflicts with the patient and/or the next of kin and/or other healthcare staff. Limitation of care order practices varied between the respondents, but neither age nor working experience explained these differences in answers. Most physicians (85%) stated that limitations of care orders are part of their work and 81% did not find them especially burdensome. The most challenging patient groups for treatment limitations were the under-aged patients, the severely disabled patients and the patients in healthcare facilities or residing in nursing homes.

Conclusion

Making limitation of care orders is an important but often invisible part of a HEMS physician’s work. HEMS physicians expressed that patients in long-term care were often without limitations of care orders in situations where an order would have been ethically in accordance with the patient’s best interests.

Electronic supplementary material

The online version of this article (10.1186/s13049-019-0663-x) contains supplementary material, which is available to authorized users.

Helicopter air ambulance services

PURPOSE OF REVIEW

Helicopter air ambulances are an integral component of modern trauma care, and are able to transport patients to facilities with greater capabilities, extract injured patients from hostile terrain, and speed transport to a trauma center.

RECENT FINDINGS

HAA transport does not reduce the total time required to transport a patient, but it does reduce the time that the patient is between healthcare facilities. Factors that have been suggested to improve outcomes for trauma patients include the availability of advanced interventions, skilled personnel, speed, and trauma center access. Despite their potential benefits to the patient, HAA operations carry significant risks. HAA operations are among the most dangerous professions for both pilot and crew with a mortality rate greater than commercial fishing, loggers, and steelworkers. The US Federal Aviation Administration (FAA) has identified that the four most common causes of HAA accidents as inadvertent flight into instrument meteorological conditions, loss of control, controlled flight into terrain, and night conditions.

SUMMARY

HAA operations are safe and can improve patient care, but additional research is needed to improve our understanding of HAA operations and their effect on outcomes.

Loss of life years due to unavailable helicopter emergency medical service: a single base study from a rural area of Norway

Background: Despite the potential benefits of physician-staffed Helicopter Emergency Medical Service (HEMS), many dispatches to primary HEMS missions in Norway are cancelled before patient encounter. Information is sparse regarding the health consequences when medically indicated HEMS missions are cancelled and the patients are treated by a GP and ambulance staff only. We aimed to estimate the potential loss of life years for patients in these situations. Method: We included all HEMS requests in the period 2010-2013 from Sogn and Fjordane County that were medically indicated but subsequently cancelled. This provided a selection of patients, with the purpose of studying cancellations independently of the patient's medical status A multidisciplinary expert panel retrospectively assessed each patient's potential loss of life years due to the lack of helicopter transport and intervention by a HEMS physician. Results: The study included 184 patients from 176 missions. Because of unavailable HEMS, seven patients (4%) were anticipated to have lost a total of 18 life years. Three patients suffered from myocardial infarction, three from stroke and one from abdominal haemorrhage. The main contribution from HEMS care in these seven cases might have been rapid transport to definitive care. The probability of a patient losing life years when in need of HEMS evacuation was found to be 0.2%. Conclusion: During the four years period seven patients lost 18 life years. Lack of rapid transport seems to be the primary cause of lost life years in this specific geographical area. Key Points Knowledge about to what extent HEMS contributes to an increased survival and a better outcome for patients is limited. Compared to similar studies on life years gained the estimated loss of life years was minor when HEMS evacuation was unavailable in this rural area. The findings indicates that lack of rapid HEMS transport was the primary cause of the estimated loss of life years.