Outcomes of interfacility helicopter transportation in acute stroke care

Optimizing remote and rural prehospital resources using air transport of thrombectomy candidates

BACKGROUND

In Finland, the yearly number of mechanical thrombectomies for acute stroke is increasing and more patients are transported over 100 km to the comprehensive stroke centre (CSC) for definitive care. This leaves the rural townships without immediate emergency medical services (EMS) for hours. In this study we compare the EMS' estimated return times to own station after the handover of a thrombectomy candidate between two transport methods: (1) using ground transportation with an ambulance to the CSC or (2) using a hydrid strategy starting the transportation with an ambulance and continuing by air with a helicopter emergency medical services unit (HEMS).

METHODS

We reviewed retrospectively all thrombectomy candidates' transportations from the hospital district of South Ostrobothnia to definitive care at the nearest CSC, Tampere University Hospital from June 2020 to October 2022. The dispatch protocol stated that a thrombectomy candidate's transport begins immediately with an ambulance and if the local HEMS unit is available the patient is handed over to them at a rendezvous. If not, the patient is transported to the CSC by ground. Transport times and locations of the patient handovers were reviewed from the CSC's EMS database and the driving time back to ambulance station was estimated using Google maps. The HEMS unit's pilot's log was reviewed to assess their mission engagement time.

RESULTS

The median distance from the CSC to the ambulances' stations was 188 km (IQR 149-204 km) and from the rendezvous with the HEMS unit 70 km (IQR 51-91 km, p < 0.001). The estimated median driving time back to station after the patient handover at the CSC was 145 min (IQR 117-153 min) compared to the patient handover to the HEMS unit 53 min (IQR 38-68 min, p < 0.001). The HEMS unit was occupied in thrombectomy candidate's transport mission for a median of 136 min (IQR 127-148 min).

CONCLUSION

A hybrid strategy to transport thrombectomy candidates with an ambulance and a helicopter reallocates the EMS resources markedly faster back to their own district.

A hybrid strategy using an ambulance and a helicopter to convey thrombectomy candidates to definite care: a prospective observational study

BACKGROUND

Mechanical thrombectomy is the treatment of choice for large vessel occlusion strokes done only in comprehensive stroke centres (CSC). We investigated whether the transportation time of thrombectomy candidates from another hospital district could be reduced by using an ambulance and a helicopter and how this affected their recovery.

METHODS

We prospectively gathered the time points of thrombectomy candidates referred to the Tampere University Hospital from the hospital district of Southern Ostrobothnia. Primary and secondary transports were included. In Hybrid transport, the helicopter emergency medical services (HEMS) unit flew from an airport near the CSC to meet the patient during transport and continued the transport to definitive care. Ground transport was chosen only when the weather prevented flying, or the HEMS crew was occupied in another emergency. We contacted the patients treated with mechanical thrombectomy 90 days after the intervention and rated their recovery with the modified Rankin Scale (mRS). Favourable recovery was considered mRS 0-2.

RESULTS

During the study, 72 patients were referred to the CSC, 71% of which were first diagnosed at the PSC. Hybrid transport (n = 34) decreased the median time from the start of transport from the PSC to the computed tomography (CT) at the CSC when compared to Ground (n = 17) transport (84 min, IQR 82-86 min vs. 109 min, IQR 104-116 min, p < 0.001). The transport times straight from the scene to CT at the CSC were equal: median 93 min (IQR 80-102 min) in the Hybrid group (n = 11) and 97 min (IQR 91-108 min) in the Ground group (n = 10, p = 0.28). The percentages of favourable recovery were 74% and 50% in the Hybrid and Ground transport groups (p = 0.38) from the PSC. Compared to Ground transportation from the scene, Hybrid transportation had less effect on the positive recovery percentages of 60% and 50% (p = 1.00), respectively.

CONCLUSION

Adding a HEMS unit to transporting a thrombectomy candidate from a PSC to CSC decreases the transport time compared to ambulance use only. This study showed minimal difference in the recovery after thrombectomy between Hybrid and Ground transports.

Air Medical Transport for Acute Ischemic Stroke Patients: A Retrospective Cohort Study of National Trends Over an 8-Year Period

OBJECTIVE

Optimal management of ischemic stroke is time dependent. An understanding of patterns of air medical transport may identify disparities that could affect patient care.

METHODS

In this 8-year (2007-2014) observational, retrospective, cohort study, we abstracted a 20% national sample of Medicare data from patients ≥ 66 years of age hospitalized with a primary diagnosis of acute ischemic stroke who presented to the emergency department by ambulance (air or ground).

RESULTS

Among 149,751 hospitalized stroke patients who arrived by ambulance, the mean age was 81.6 years (standard deviation = 8.0 years), 62.1% were female (n = 93,007), and 86.3% were White (n = 129,268). Of these, 5,534 patients (3.7%) used any form of air ambulance. Air ambulance use (2007: 2.5%, 2014: 4.9%; P < .001) and arrival at certified stroke centers (2007: 40.3%, 2014: 63.2%; P < .001) increased over time. Air ambulance use was less likely among older patients (76-85 years and >85 years vs. 66-75 years; odds ratio [OR] = 0.68; 95% confidence interval [CI], 0.64-0.72 and OR = 0.34; 95% CI, 0.32-0.37, respectively) and all racial minorities except American Natives (OR = 2.07; 95% CI, 1.57-2.73) and more likely among sicker patients (Charlson Comorbidity Index ≥ 2 vs. 1, OR = 1.23; 95% CI, 1.09-1.38) and rural residents (OR = 1.34; 95% CI, 1.09-1.64). After adjustment for covariates, air ambulance use was associated with higher odds of thrombolysis (adjusted OR = 2.57; 95% CI, 2.38-2.79).

CONCLUSION

Air ambulance use is independently associated with increased thrombolysis use for stroke, but disparities exist in both air ambulance and thrombolysis use. Further research into underlying causes for these disparities would be beneficial for systems and public health-based interventions for improving outcomes for ischemic stroke.

Impact of a ground intermediate transport from the helicopter landing site at a hospital on transport duration and patient safety

BACKGROUND

Helicopter emergency medical service provides timely care and rapid transport of severely injured or critically ill patients. Due to constructional or regulatory provisions at some hospitals, a remote helicopter landing site necessitates an intermediate ground transport to the emergency department by ambulance which might lengthen patient transport time and comprises the risk of disconnection or loss of vascular access lines, breathing tubes or impairment of other relevant equipment during the loading processes. The aim of this study was to evaluate if a ground intermediate transport at the hospital site prolonged patient transport times and operating times or increases complication rates.

METHODS

A retrospective analysis of all missions of a German air rescue service between 2012 and 2020 was conducted. Need of a ground transport at the accepting hospital, transfer time from the helipad to the hospital, overall patient transport time from the emergency location or the referring hospital to the accepting hospital and duration of the mission were analyzed. Several possible confounders such as type of mission, mechanical ventilation of the patient, use of syringe infusion pumps (SIPs), day- or nighttime were considered.

RESULTS

Of a total of 179,003 missions (92,773 (51,8%) primary rescue missions, 10,001 (5,6%) polytrauma patients) 86,230 (48,2%) secondary transfers) an intermediate transport by ambulance occurred in 40,459 (22,6%) cases. While transfer times were prolonged from 6.3 to 8.8 min for primary rescue cases (p < 0.001) and from 9.2 to 13.5 min for interhospital retrieval missions (p < 0.001), the overall patient transport time was 14.8 versus 15.8 min (p < 0.001) in primary rescue and 23.5 versus 26.8 min (p < 0.001) in interhospital transfer. Linear regression analysis revealed a mean time difference of 3.91 min for mechanical ventilation of a patient (p < 0.001), 7.06 min for the use of SIPs (p < 0.001) and 2.73 min for an intermediate ambulance transfer (p < 0.001). There was no relevant difference of complication rates seen.

CONCLUSIONS

An intermediate ground transport from a remote helicopter landing site to the emergency department by ambulance at the receiving hospital had a minor impact on transportation times and complication rates.

The Impact of Weather and Mode of Transport on Outcomes of Patients With Acute Ischemic Stroke Undergoing Mechanical Thrombectomy

BACKGROUND

Efficient transfer to mechanical thrombectomy (MT)-capable centers is essential for patients with stroke. Weather may influence stroke risk, transportation, and outcomes.

OBJECTIVE

To investigate how weather affects stroke patient transfer and outcomes after MT.

METHODS

We retrospectively collected data for patients with stroke transferred from spoke to our hub hospital to undergo MT between 2017 and 2021. We examined associations between weather, transportation, and patient outcomes.

RESULTS

We included 543 patients with a mean age of 71.7 years. The median National Institutes of Health Stroke Score increased from 14 to 15 after transportation. The median modified Rankin Scale was 4 at discharge and 90 days, and 3 at the final follow-up (mean 91.7 days). Higher daily temperatures were associated with good outcome, whereas daily drizzle was associated with poor outcome. More patients were transferred by air when visibility was better, and by ground during heavier precipitation, higher humidity, rain, mist, and daily drizzle, fog, and thunder . Patient outcomes were not associated with transportation mode. Among the independent predictors of good outcome, none was a weather variable. Lower hourly relative humidity ( P = .003) and longer road distance ( P < .001) were independent predictors of using air transportation, among others.

CONCLUSION

During transportation, higher temperature was associated with good outcome, whereas daily drizzle was associated with poor outcome after MT. Although weather was associated with transportation mode, no differences in outcomes were found between transportation modes. Further studies are needed to modify transfer protocols, especially during cold and rainy days, and potentially improve outcomes.

Telestroke networks for area-wide access to endovascular stroke treatment

BACKGROUND

Endovascular therapy (EVT) offers a highly effective therapy for patients with acute ischemic stroke due to large vessel occlusion. Comprehensive stroke centers (CSC) are required to provide permanent accessibility to EVT. However, when affected patients are not located in the immediate catchment area of a CSC, i.e. in rural or structurally weaker areas, access to EVT is not always ensured.

MAIN BODY

Telestroke networks play a crucial role in closing this healthcare coverage gap and thereby support specialized stroke treatment. The aim of this narrative review is to elaborate the concepts for the indication and transfer of EVT candidates via telestroke networks in acute stroke care. The targeted readership includes both comprehensive stroke centers and peripheral hospitals. The review is intended to identify ways to design care beyond those areas with narrow access to stroke unit care to provide the indicated highly effective acute therapies on a region-wide basis. Here, the two different models of care: "mothership" and "drip-and-ship" concerning rates of EVT and its complications as well as outcomes are compared. Decisively, forward-looking new model approaches such as a third model the "flying/driving interentionalists" are introduced and discussed, as far as few clinical trials have investigated these approaches. Diagnostic criteria used by the telestroke networks to enable appropriate patient selection for secondary intrahospital emergency transfers are displayed, which need to meet the criteria in terms of speed, quality and safety.

CONCLUSION

The few findings from the studies with telestroke networks are neutral for comparison in the drip-and-ship and mothership models. Supporting spoke centres through telestroke networks currently seems to be the best option for offering EVT to a population in structurally weaker regions without direct access to a CSC. Here, it is essential to map the individual reality of care depending on the regional circumstances.

A Conceptual Framework for Optimizing the Equity of Hospital-Based Emergency Care: The Structure of Hospital Transfer Networks

Policy Points Current pay-for-performance and other payment policies ignore hospital transfers for emergency conditions, which may exacerbate disparities. No conceptual framework currently exists that offers a patient-centered, population-based perspective for the structure of hospital transfer networks. The hospital transfer network equity-quality framework highlights the external and internal factors that determine the structure of hospital transfer networks, including structural inequity and racism.

CONTEXT

Emergency care includes two key components: initial stabilization and transfer to a higher level of care. Significant work has focused on ensuring that local facilities can stabilize patients. However, less is understood about transfers for definitive care. To better understand how transfer network structure impacts population health and equity in emergency care, we proposea conceptual framework, the hospital transfer network equity-quality model (NET-EQUITY). NET-EQUITY can help optimize population outcomes, decrease disparities, and enhance planning by supporting a framework for understanding emergency department transfers.

METHODS

To develop the NET-EQUITY framework, we synthesized work on health systems and quality of health care (Donabedian, the Institute of Medicine, Ferlie, and Shortell) and the research framework of the National Institute on Minority Health and Health Disparities with legal and empirical research.

FINDINGS

The central thesis of our framework is that the structure of hospital transfer networks influences patient outcomes, as defined by the Institute of Medicine, which includes equity. The structure of hospital transfer networks is shaped by internal and external factors. The four main external factors are the regulatory, economic environment, provider, and sociocultural and physical/built environment. These environments all implicate issues of equity that are important to understand to foster an equitable population-based system of emergency care. The framework highlights external and internal factors that determine the structure of hospital transfer networks, including structural racism and inequity.

CONCLUSIONS

The NET-EQUITY framework provides a patient-centered, equity-focused framework for understanding the health of populations and how the structure of hospital transfer networks can influence the quality of care that patients receive.

Adjusted horizontal stacked bar graphs (“Grotta bars”) for consistent presentation of observational stroke study results

Background:

Modified Rankin Scale (mRS) scores are used to measure functional outcomes after stroke. Researchers create horizontal stacked bar graphs (nicknamed “Grotta bars”) to illustrate distributional differences in scores between groups. In well-conducted randomized controlled trials, Grotta bars have a causal interpretation. However, the common practice of exclusively presenting unadjusted Grotta bars in observational studies can be misleading in the presence of confounding. We demonstrated this problem and a possible solution using an empirical comparison of 3-month mRS scores among stroke/TIA patients discharged home versus elsewhere after hospitalization.

Patients and methods:

Using data from the Berlin-based B-SPATIAL registry, we estimated the probability of being discharged home conditional on prespecified measured confounding factors and generated stabilized inverse probability of treatment (IPT) weights for each patient. We visualized mRS distributions by group with Grotta bars for the IPT-weighted population in which measured confounding was removed. We then used ordinal logistic regression to quantify unadjusted and adjusted associations between being discharged home and the 3-month mRS score.

Results:

Of 3184 eligible patients, 2537 (79.7%) were discharged home. In the unadjusted analyses, those discharged home had considerably lower mRS compared with patients discharged elsewhere (common odds ratio, cOR = 0.13, 95% CI: 0.11–0.15). After removing measured confounding, we obtained substantially different mRS distributions, visually apparent in the adjusted Grotta bars. No statistically significant association was found after confounding adjustment (cOR = 0.82, 95% CI: 0.60–1.12).

Discussion and conclusion:

The practice of presenting only unadjusted stacked bar graphs for mRS scores together with adjusted effect estimates in observational studies can be misleading. IPT weighting can be implemented to create Grotta bars that account for measured confounding, which are more consistent with the presentation of adjusted results in observational studies.

Effect of Helicopter Transportation of Acute Ischemic Stroke Patients on Mortality and Functional Outcomes: A Systematic Review and Meta-Analysis

OBJECTIVE

The "time is brain" concept denotes the importance of the expedited transfer of patients to stroke care centers. Helicopter emergency medical services (HEMS) can reduce the time to definitive care, which could improve neurologic prognosis and reduce mortality.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, a search for randomized controlled trials, nonrandomized controlled trials, and prospective and retrospective cohort studies was performed through specific databases from inception to February 2020. Helicopter, acute stroke, and their synonyms (according to Medical Subject Headings) were included in this search. The Newcastle-Ottawa Scale was used to assess the quality of the included studies, and the Egger test was used to assess for publication bias.

RESULTS

A total of 8 studies matched the inclusion criteria and were included for meta-analysis. The overall number recruited for helicopter transportation was 1,372, and for emergency standard transportation, it was 8,587. The association among HEMS and mortality was not statistically significant (odds ratio [OR] = 0.7; 95% confidence interval [CI], 0.60-1.06; P = .12). There was a significant association between good outcomes and HEMS (OR = 2; 95% CI, 1.79-2.34; P ≤ .001), and the overall poor neurologic outcome was reduced (OR = 0.52; 95% CI, 0.46-0.60; P ≤ .001).

CONCLUSION

A good neurologic outcome was higher with HEMS compared with emergency standard transportation. The mortality rate was less in the emergency standard transportation group after pooled analysis but was not significant; the reduction in a poor outcome was statistically significant.