Helicopter transportation in the era of thrombectomy: The next frontier for acute stroke treatment and research

Initiation of mechanical thrombectomy in an insular setting with helicopter transfer: a 2-year experience from the first, complete, tertiary stroke center in the Caribbean

BACKGROUND

This is the first cohort study of patients treated with mechanical thrombectomy (MT) for acute ischemic stroke in the French West Indies, with a mothership center and helicopter transfer.

OBJECTIVE

To describe the population and to evaluate imaging, clinical, and time metric outcomes, in order to assess the feasibility and adjust the territorial organization.

METHODS

In this observational study, we retrospectively analyzed our prospectively collected data of a population of consecutive patients treated with MT for anterior and posterior circulation large vessel occlusions. Primary outcome was 3-month functional independence (modified Rankin Scale score ≤2). Secondary outcomes included aerial and terrestrial times of arrival, in-hospital delays, demographics, imaging and clinical data at onset, discharge, and at 3 months. We compared the results of the mothership and drip-and-ship paradigms.

RESULTS

Between January 2020 and December 2021, 223 patients were included (74% mothership, 26% drip-and-ship). Mean National Institutes of Health Stroke Scale (NIHSS) score of the population was 16 before MT, with significant reduction (NIHSS score 6) at discharge (9 mothership, 12 drip-and-ship, P=0.025). There was significant difference in onset-to-operation room times among the two centers (335 min mothership, 500 min drip-and-ship, P=0.004). Successful recanalization (modified Thrombolysis in Cerebral Infarction score 2b-3) was 80.3%. Functional independence at 3 months was 35%, symptomatic intracranial hemorrhage was 11%, and the complication rate was 9.4%, all without statistically significant difference between the two groups.

CONCLUSION

The population has distinct risk factors. MT with helicopter transfer is feasible in the French West Indies. Reduction of prehospital and in-hospital times is mandatory; evaluation of the territorial strategy is underway, to avoid over-selection of transferred patients.

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.

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.

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.

Appropriate Air Medical Services Utilization and Recommendations for Integration of Air Medical Services Resources into the EMS System of Care: A Joint Position Statement and Resource Document of NAEMSP, ACEP, and AMPA

Air medical services involves providing medical care in transit while using either fixed wing (airplane) or rotor wing (helicopter) aircraft to move patients between locations. The modern use and availability of air medical services has expanded access to various health system resources, including specialty care. While this is generally beneficial, such expansion has also contributed to the complexity of health care delivery systems.(1, 2) Since the publication of the 2013 joint position statement Appropriate and Safe Utilization of Helicopter Emergency Medical Services,(3) research has shown that patient benefit is gained from the clinical care capabilities of air medical services independent of potential time saved when transporting patients.(4-6) Because the evidence basis for utilization of air medical services continues to evolve, NAEMSP, ACEP, and AMPA believe that an update regarding the appropriate utilization of air medical services is warranted, and that such guidance for utilization can be divided into three major categories: clinical considerations, safety considerations, and system integration and quality assurance considerations.

Risk and space: modelling the accessibility of stroke centers using day- & nighttime population distribution and different transportation scenarios

Purpose

Rapid accessibility of (intensive) medical care can make the difference between life and death. Initial care in case of strokes is highly dependent on the location of the patient and the traffic situation for supply vehicles. In this methodologically oriented paper we want to determine the inequivalence of the risks in this respect.

Methods

Using GIS we calculate the driving time between Stroke Units in the district of Münster, Germany for the population distribution at day- & nighttime. Eight different speed scenarios are considered. In order to gain the highest possible spatial resolution, we disaggregate reported population counts from administrative units with respect to a variety of factors onto building level.

Results

The overall accessibility of urban areas is better than in less urban districts using the base scenario. In that scenario 6.5% of the population at daytime and 6.8% at nighttime cannot be reached within a 30-min limit for the first care. Assuming a worse traffic situation, which is realistic at daytime, 18.1% of the population fail the proposed limit.

Conclusions

In general, we reveal inequivalence of the risks in case of a stroke depending on locations and times of the day. The ability to drive at high average speeds is a crucial factor in emergency care. Further important factors are the different population distribution at day and night and the locations of health care facilities. With the increasing centralization of hospital locations, rural residents in particular will face a worse accessibility situation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12942-021-00284-y.

Geographic Access to Stroke Care Services in Rural Communities in Ontario, Canada

BACKGROUND

Optimal stroke care requires access to resources such as neuroimaging, acute revascularization, rehabilitation, and stroke prevention services, which may not be available in rural areas. We aimed to determine geographic access to stroke care for residents of rural communities in the province of Ontario, Canada.

METHODS

We used the Ontario Road Network File database linked with the 2016 Ontario Acute Stroke Care Resource Inventory to estimate the proportion of people in rural communities, defined as those with a population size <10,000, who were within 30, 60, and 240 minutes of travel time by car from stroke care services, including brain imaging, thrombolysis treatment centers, stroke units, stroke prevention clinics, inpatient rehabilitation facilities, and endovascular treatment centers.

RESULTS

Of the 1,496,262 people residing in rural communities, the majority resided within 60 minutes of driving time to a center with computed tomography (85%), thrombolysis (81%), a stroke unit (68%), a stroke prevention clinic (74%), or inpatient rehabilitation (77.0%), but a much lower proportion (32%) were within 60 minutes of driving time to a center capable of providing endovascular thrombectomy (EVT).

CONCLUSIONS

Most rural Ontario residents have appropriate geographic access to stroke services, with the exception of EVT. This information may be useful for jurisdictions seeking to optimize the regional organization of stroke care services.

The "Flying Intervention Team": A Novel Stroke Care Concept for Rural Areas

BACKGROUND

Endovascular treatment of large vessel occlusion in acute ischemic stroke patients is difficult to establish in remote areas, and time dependency of treatment effect increases the urge to develop health care concepts for this population.

SUMMARY

Current strategies include direct transportation of patients to a comprehensive stroke center (CSC) ("mothership model") or transportation to the nearest primary stroke center (PSC) and secondary transfer to the CSC ("drip-and-ship model"). Both have disadvantages. We propose the model "flying intervention team." Patients will be transported to the nearest PSC; if telemedically identified as eligible for thrombectomy, an intervention team will be acutely transported via helicopter to the PSC and endovascular treatment will be performed on site. Patients stay at the PSC for further stroke unit care. This model was implemented at a telestroke network in Germany. Fifteen remote hospitals participated in the project, covering 14,000 km2 and a population of 2 million. All have well established telemedically supported stroke units, an angiography suite, and a helicopter pad. Processes were defined individually for each hospital and training sessions were implemented for all stroke teams. An exclusive project helicopter was installed to be available from 8 a.m. to 10 p.m. during 26 weeks per year. Key Messages: The model of the flying intervention team is likely to reduce time delays since processes will be performed in parallel, rather than consecutively, and since it is quicker to move a medical team rather than a patient. This project is currently under evaluation (clinicaltrials NCT04270513).

Comparative Study on the Outcome of Stroke Patients Transferred by Doctor Helicopters and Ground Ambulances in South Korea: A Retrospective Controlled Study

The purpose of this study was to analyze the effectiveness of helicopter emergency medical services (HEMS) for its economic operations in South Korea. This study targeted stroke patients who were transported via HEMS or ground emergency medical services (GEMS) from the scene of an accident to a regional emergency medical center. From this patient population, stroke patients who traveled at least 50 km from the scene of the cerebral infarction to the hospital with analyzable outcome data were extracted and included in this study. This study included 26 HEMS and 102 GEMS stroke patients from a pool of 183 potential patients. The survival-to-discharge rate of patients transported via HEMS (96.2%; 25/26) was significantly higher than that of patients transported via GEMS (83.2%; 104/128) (P=0.001). The HEMS transfer was quicker with respect to the decision-making process because the emergency physician actively evaluates and communicates on-site and during in-transit travel to request an appointment immediately upon arrival at the emergency room. These results indicate that using HEMS increased discharge and survival rates and reduced in-hospital mortality of HEMS of stroke patients with a reduced admission time. This result association leads to reasonable cost-effectiveness and efficient estimates overall. In conclusion, HEMS indicate reduced time taken for stroke patients to be hospitalized and treated and decreased mortality after 24 hours. According to this result, HEMS transport can be more effective than GEMS in long-distance delivery of stroke patients.

Secondary transfer of emergency stroke patients eligible for mechanical thrombectomy by air in rural England: economic evaluation and considerations

Background

Mechanical thrombectomy (MT) is a time-sensitive emergency procedure for patients who had ischaemic stroke leading to improved health outcomes. Health systems need to ensure that MT is delivered to as many patients as quickly as possible. Using decision modelling, we aimed to evaluate the cost-effectiveness of secondary transfer by helicopter emergency medical services (HEMS) compared with ground emergency medical services (GEMS) of rural patients eligible for MT in England.

Methods

The model consisted of (1) a short-run decision tree with two branches, representing secondary transfer transportation strategies and (2) a long-run Markov model for a theoretical population of rural patients with a confirmed ischaemic stroke. Strategies were compared by lifetime costs: quality-adjusted life years (QALYs), incremental cost per QALY gained and net monetary benefit. Sensitivity and scenario analyses explored uncertainty around parameter values.

Results

We used the base case of early-presenting (<6 hours to arterial puncture) patient aged 75 years who had stroke to compare HEMS and GEMS. This produced an incremental cost-effectiveness ratio (ICER) of £28 027 when a 60 min reduction in travel time was assumed. Scenario analyses showed the importance of the reduction in travel time and futile transfers in lowering ICERs. For late presenting (>6 hours to arterial puncture), ground transportation is the dominant strategy.

Conclusion

Our model indicates that using HEMS to transfer patients who had stroke eligible for MT from remote hospitals in England may be cost-effective when: travel time is reduced by at least 60 min compared with GEMS, and a £30 000/QALY threshold is used for decision-making. However, several other logistic considerations may impact on the use of air transportation.

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.

Outcomes of interfacility helicopter transportation in acute stroke care

OBJECTIVE

To evaluate the long-term functional outcome of interhospital transfer of patients with stroke with suspected large vessel occlusion (LVO) using Helicopter Emergency Medical Services (HEMS).

METHODS

Records of consecutive patients evaluated through 2 telestroke networks and transferred to thrombectomy-capable stroke centers between March 2017 and March 2018 were reviewed. Inverse probability of treatment weighting (IPTW) using the propensity score was performed to address confounding factors. Multivariate logistic regression analysis with IPTW was used to determine whether HEMS were associated with good long-term functional outcome (modified Rankin scale score ≤ 2).

RESULTS

A total of 199 patients were included; median age was 67 years (interquartile range [IQR] 55-79 years), 90 (45.2%) were female, 120 (60.3%) were white, and 100 (50.3%) were transferred by HEMS. No significant differences between the 2 groups were found in mean age, sex, race, IV tissue plasminogen activator (tPA) receipt, and thrombectomy receipt. The median baseline NIH Stroke Scale score was 14 (IQR 9-18) in the helicopter group vs 11 (IQR 6-18) for patients transferred by ground (p = 0.039). The median transportation time was 60 minutes (IQR 49-70 minutes) by HEMS and 84 minutes (IQR 25-102 minutes) by ground (p < 0.001). After weighting baseline characteristics, the use of HEMS was associated with higher odds of good long-term outcome (OR 4.738, 95% CI 2.15-10.444, p < 0.001) controlling for transportation time, door-in-door-out time, and thrombectomy and tPA receipt. The magnitude of the HEMS effect was larger in thrombectomy patients who had successful recanalization (OR 1.758, 95% CI 1.178-2.512, p = 0.027).

CONCLUSIONS

HEMS use was associated with better long-term functional outcome in patients with suspected LVO, independently of transportation time.

Low-Frequency Vibrations Enhance Thrombolytic Therapy and Improve Stroke Outcomes

Background and Purpose- We aim to determine the potential impact on stroke thrombolysis of drip-and-ship helicopter flights and specifically of their low-frequency vibrations (LFVs). Methods- Mice with a middle cerebral artery autologous thromboembolic occlusion were randomized to receive rtPA (recombinant tissue-type plasminogen activator; or saline) 90 minutes later in 3 different settings: (1) a motion platform simulator that reproduced the LFV signature of the helicopter, (2) a standardized actual helicopter flight, and (3) a ground control. Results- Mice assigned to the LFV simulation while receiving tPA had smaller infarctions (31.6 versus 54.9 mm3; P=0.007) and increased favorable neurological outcomes (86% versus 28%; P=0.0001) when compared with ground controls. Surprisingly, mice receiving tPA in the helicopter did not exhibit smaller infarctions (47.8 versus 54.9 mm3; P=0.58) nor improved neurological outcomes (37% versus 28%; P=0.71). This could be due to a causative effect of the 20- to 30-Hz band, which was inadvertently attenuated during actual flights. Mice using saline showed no differences between the LFV simulator and controls with respect to infarct size (80.9 versus 95.3; P=0.81) or neurological outcomes (25% versus 11%; P=0.24), ruling out an effect of LFV alone. There were no differences in blood-brain barrier permeability between LFV simulator or helicopter, compared with controls (2.45-3.02 versus 4.82 mm3; P=0.14). Conclusions- Vibration in the low-frequency range (0.5-120 Hz) is synergistic with rtPA, significantly improving the effectiveness of thrombolysis without impairing blood-brain barrier permeability. Our findings reveal LFV as a novel, safe, and simple-to-deliver intervention that could improve the outcomes of patients. Visual Overview- An online visual overview is available for this article.

The impact of helicopter emergency medical service on acute ischemic stroke patients: A systematic review

BACKGROUND

Helicopter emergency medical services (HEMS) is commonly elected transport for acute ischemic stroke (AIS) known as a time-critical illness.

AIM

To conduct a systematic review in order to explore the HEMS impact on healthcare status, process and outcome measures for AIS patients.

METHODS

A systematic search was conducted of PubMed, Medline, CINAHL, Cochrane Library and Google Scholar. The gray literature and reference lists of included articles were also searched. Thirty studies met inclusion criteria.

RESULTS

Using Donabedian's framework, two studies focused on the impact on healthcare structure, twenty-three explored the impact on process measures, and five focused on clinical outcomes. HEMS structure implications could not be assessed due to insufficient studies. HEMS showed no significant outcome benefit compared to ground emergency medical services (EMS) and the impact on process measures was ambiguous.

CONCLUSIONS

HEMS necessity varied considerably between studies. More robust studies are needed for detection of the most suitable use of HEMS in AIS.

Efficacy of the Drip and Ship Method in 24-h Helicopter Transportation and Teleradiology for Isolated Islands

Our hospital, located on the mainland, serves as a hub center for nine hospitals on the remote islands of Nagasaki Prefecture, Japan. There are no stroke specialists on these islands. We can transfer emergency patients from these islands to our hospital at any time, using a teleradiology system and three types of helicopter transport. We examined the efficacy of the drip and ship (DS) method for treating patients with acute ischemic stroke (AIS) on these islands, in comparison with patients on the mainland. From 2010 to 2017, we reviewed 98 consecutive patients with AIS who received intravenous recombinant tissue plasminogen activator (IV rt-PA) in our hospital or were transported to our hospital after IV rt-PA. Patients were divided into the Islands group (received IV rt-PA on the islands, DS; 31 cases) and the Mainland group (67 cases). The median transport distance from the islands was 112 km. The rate of patients achieving favorable outcomes was 54.8% in the Islands group and 64.2% in the Mainland group, with no significant differences. Multivariate analysis revealed that patients living on isolated islands did not have increased risks of unfavorable outcomes. Endovascular therapy (EVT), as part of the drip, ship, and retrieve method, was performed in 22.6% of patients in the Islands group and EVT in 38.8% of those in the Mainland group. The DS method seems feasible and safe for patients living on isolated islands with the use of 24-h helicopter transportation and teleradiology.

Polish Helicopter Emergency Medical Service (HEMS) Response to Stroke: A Five-Year Retrospective Study

Background

A stroke is a serious life-threatening emergency that requires immediate intervention in an appropriate therapeutic center. The aim of this study was to analyze the time of medical procedures at the scene and changes in the state of stroke patients during transport by HEMS in Poland. The presented research is the first nationwide study covering such a large group of stroke patients, for whom aerial support was used in the therapeutic process.

Material/Methods

A retrospective cross-sectional study of 48553 missions performed by Polish Medical Air Rescue (PMAR) during the 5-year study period resulted in 3906 stroke patients who, after medical rescue operations by HEMS crew, were transported by helicopters to hospitals.

Results

Helicopters in 3475 (88.97%) cases were utilized as a support for Ground Emergency Medical Service (GEMS). The maximum duration of HEMS operation from activation to patient transfer to the hospital did not exceed 108 min and the median was 60 min. Over 87% of patients with HEMS reported stroke symptoms and arrived at the medical center with the possibility of implementing thrombolytic therapy. The factor that affected the deterioration of patients’ condition was the drawing out of the extent of time spent by the crew at the scene.

Conclusions

The use of HEMS in Poland in the case of patients with stroke symptoms ensures fast and professional assistance at the site of the medical emergency as well as safe transport to specialized centers, shortening the time of proper treatment implementation.

Disparities in Inter-hospital Helicopter Transportation for Hispanics by Geographic Region: A Threat to Fairness in the Era of Thrombectomy

BACKGROUND AND PURPOSE

Mechanical thrombectomy (MT) is a time-dependent therapy that is only available at a limited number of hospitals. As such, patients that live at a considerable distance of those specialized centers often require rapid interhospital emergent evacuation with Helicopter Emergency Medical Services (HEMS) to be considered for MT. It is not known whether the use of HEMS is equitable across different groups of patients.

METHODS

Acute ischemic stroke patients emergently transferred to another facility were identified in a retrospective review of a large Medicare claims database. Mode of transportation (HEMS, advanced, or basic ground ambulances) was determined by CPT codes. Distance from patient's residence to the closest center with MT capabilities was calculated. Generalized linear mixed logit models were used to determine the odds of HEMS relative to ground services for Hispanic and non-Hispanic black (NHB) patients relative to non-Hispanic white (NHW) patients while controlling for confounders.

RESULTS

A total of 8027 patients that underwent emergent interhospital transportation were analyzed. HEMS utilization was 18.1% for NHB, 20.6% for Hispanics, and 21.6% for NHW (P = .054). In adjusted analyses for confounders, including distance to a MT-capable hospital, Hispanic patients were less likely than NHWs to be transported by HEMS. While that association had marginal significance for the whole United States (OR = .76; 95% CI, .57-1.01; P = .055), it was statistically significant for patients living in the southern region of the United States (OR = .6; 95% CI, .40-.92; P = .019).

DISCUSSION

Our findings suggest there is a disparity in the use of HEMS in Hispanic stroke patients compared to NHW. Such a disparity may delay arrival to a MT-capable hospital, delay treatment times, or lead to ineligibility for MT altogether. Given the known benefit of MT and known existing disparities in stroke treatment and outcomes, it is important to further investigate and address disparities in mode of interhospital transportation.

Helicopter "Drip and Ship" Flights Do Not Alter the Pharmacological Integrity of rtPA

INTRODUCTION

Rural and critical access hospitals rely on the "drip and ship" practice using helicopter emergency medical services (HEMS). But those helicopter flights are an unusual environment with physical factors such as vibration and accelerations that could potentially affect the stability, and pharmacological properties of IV rtPA, an issue that has not been previously addressed.

MATERIALS AND METHODS

This was a prospective cohort study of consecutive acute ischemic stroke patients receiving IV rtPA through a Comprehensive Stroke Center from November 2015 to February 2017 to measure the effects of HEMS on the integrity and activity of rtPA by collecting residual medication left in the vial.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. NCT02752256 RESULTS: A total of 33 patients and rtPA samples were included; 18 patients who presented directly to the Comprehensive Stroke Center emergency department and 15 patients who received rtPA during air ambulance transfer. The median rtPA antigen concentration in the residual medication vial was 3.04 mg/mL (IQR: 1.24-3.87) in the HEMS group and 1.91 mg/mL (IQR: 1.33-2.60) in the controls (P = .168). There were no significant differences in rtPA activity or specific activity between the HEMS and control groups and there was no association between total HEMS flight time on overall rtPA specific activity.

CONCLUSIONS

In summary, this study provides supportive evidence of the lack of a detrimental effect of the HEMS physical environment on the integrity of rtPA, therefore endorsing current drip and ship practices without infusion adjustments.