Mobile Stroke Unit Research Articles

Abstract 1122‐000126: Mobile Stroke Unit Process Metrics in Large Vessel Occlusion Stroke Patients: BEST‐MSU Substudy

Introduction : Mobile Stroke Units (MSUs) speed thrombolytic treatment for acute ischemic stroke and improve clinical outcomes compared to standard management by Emergency Medical Services (EMS). However, MSU process metrics in the subset of patients with large vessel occlusions (LVOs) having endovascular thrombectomy (EVT) have yet to be optimized. Methods : A pre‐specified Benefits of Stroke Treatment Using a Mobile Stroke Unit (BEST‐MSU) substudy of tPA‐eligible stroke patients with imaging evident LVOs was conducted. The primary outcome was process metrics related to treatment times from stroke onset and first medical alert. Safety outcomes included rates of symptomatic intracerebral hemorrhage and procedural complications. Groups were compared using Chi‐square or Fisher’s exact tests for categorical variables, and Wilcoxon rank‐sum tests for continuous variables. Results : A total of 295 patients were included, 169 in the MSU group and 126 in the EMS group. Baseline characteristics were comparable between the groups, with the exception of baseline NIHSS (MSU mean 19.0 [IQR 13.0,23.0] vs EMS 16.0 [11.0, 20.0], p = 0.003). 92% of MSU and 87% of EMS LVO patients received tPA, and 78% and 85% went on to have EVT. Process metrics are detailed in Table 1. MSU LVO patients had faster tPA bolus from 911‐alert (MSU 45.0 minutes [40.0, 53.5] vs EMS 76.0 [64.0, 87.8], p<0.001), however the two groups had similar alert to groin puncture (MSU 142.5 [116.8, 171.0] versus EMS 131.5 [114.0, 159.8], p = 0.15). MSU patients spent more time on‐scene, (EMS arrival to ED arrival, 53.0 [45.0, 62.0] vs 27.0 [22.0, 33.0], p<0.001) however less time prior to EVT (door to groin puncture, 76.5 [54.8, 108.5] vs 94.0 [72.0, 123.0], p<0.001) with variable use of field CTAs and direct cath lab admission with ED bypass, yielding a net neutral result. The variability among site protocols is reflected in the range of median alert to groin puncture times (minimum 107.0 minutes, maximum 152.0). In the 222 patients undergoing EVT, median alert to recanalization time was 181.5 minutes [146.8, 225.5] in the MSU group and 190.5 [157.5, 227.5] in the EMS group (p = 0.47). Recanalization (Thrombolysis In Cerebral Infarction [TICI] 2b/3) was achieved in 76% of MSU and 70% of EMS (p = 0.32) with comparable rates of EVT complications (including hemorrhage, perforation, dissection, hematoma). 54% MSU and 44% of EMS LVO patients achieved good functional outcome (modified Rankin Scale [mRS] ≤ 2) at 90 days (p = 0.11). Conclusions : In tPA‐eligible LVO stroke patients, MSU management did not increase or expedite EVT treatment times as compared to standard EMS management. Future MSU processes should include field CTA with direct admission to cath labs to maximize the early treatment advantage this technology provides.

Mobile Stroke Units Yield Significant Clinical Benefits and Less Disability at 90 Days

Mobile Stroke Units Yield Significant Clinical Benefits and Less Disability at 90 Days

Telemedicine-enabled ambulances and mobile stroke units for prehospital stroke management

The recognition and management of stroke in the prehospital setting has become increasingly important to improve patient outcomes. Several strategies to advance prehospital stroke care have been developed, including the mobile stroke unit and the telemedicine-enabled ambulance—or “mini-MSU.” These strategies both incorporate ambulance-based audio-visual telemedicine evaluation with a vascular neurologist to facilitate faster treatment but differ in several areas including upfront and recurring costs, scalability or growth potential, ability to integrate into existing emergency medical services systems, and interoperability across multiple specialties or conditions. While both the mobile stroke unit and mini-mobile stroke unit model are valid approaches to improve stroke care, the authors aim to compare these models based on costs, scalability, integration, and interoperability in order to guide our prehospital leaders to find the best solutions for their communities.

Mobile Stroke Units Facilitate Prehospital Management of Intracerebral Hemorrhage.

Mobile stroke units (MSUs) improve reperfusion therapy times in acute ischemic stroke (AIS). However, prehospital management options for intracerebral hemorrhage (ICH) are less established. We describe the initial Melbourne MSU experience in ICH. Consecutive patients with ICH and AIS treated by the Melbourne MSU were included. We describe demographics, proportions of patients receiving specific therapies, and bypass to comprehensive/neurosurgical centers. We also compare operational time metrics between patients with MSU-ICH and MSU-AIS. During a 2-year period, the Melbourne MSU managed 49 patients with ICH, mean (SD) age 74 (12) years, median (interquartile range) National Institutes of Health Stroke Scale 17 (12–20). Intravenous antihypertensives were the commonest treatment provided (46.9%). Bypass of a primary center to a comprehensive center with neurosurgical expertise occurred in 32.7% of patients with MSU-ICH compared with 20.5% of patients with MSU-AIS. Compared with patients with MSU-AIS, patients with MSU-ICH had faster onset-to-emergency-call, and onset-to-scene-arrival times at the median and 75th percentiles. MSUs can facilitate ultra-early ICH diagnosis, management, and triage.

Telemedicine for stroke

The term “telestroke” was first introduced by Levine ad Gorman in 1999. Since then many telestroke networks have been developed throughout the world more than 22 in Germany alone, performing more than 38.211 teleconsultations per year. Most telestroke networks are organized in a hub and spokes system: one or several comprehensive stroke centers (hub), advise several regional or community hospitals (spoke) in stroke care. The degree of treatment possibilities in the spokes hospitals is highly variable; while some telestroke networks offer only hyperacute stroke treatment i.e. identifying strokes and performing thrombolysis onsite (TSRH-telemedicine-assisted Stroke Ready Hospitals), others have developed local stroke Units (TSU-Telemedical Stroke Units) and provide stroke care until the patient is discharged home/to a rehabilitation center. The backbone of every functioning telestroke network remains the implementation of standard operational procedures, regular staff trainings and quality management. Nowadays, telestroke is going far beyond thrombolysis and stroke unit treatment - the ultimate goal being to treat stroke patients from the beginning to the end remotely as close to the patients home as possible. Multiple telestroke projects target stroke from the onset to its rehabilitation and follow up care. To mention only a few, mobile stroke Units including CT scanners have brought thrombolysis to the patients front door, interventionalists are been flown by helicopter to regional hospitals to perform thrombectomy onsite, and patients are being discharged home with telerehabilitation programs. In conclusion, telestroke is a growing field, bringing qualitative and innovative stroke care closer to the patient.

Systems of care from pre-hospital to emergency department

This lecture will cover systems of care to streamline acute stroke management and optimise patient outcomes. In the pre-hospital space we will discuss paramedic severity-based triage and potential bypass to endovascular-capable hospitals including the results of the RACECAT trial. Mobile Stroke Unit developments including results of the B_PROUD and BEST MSU studies will be covered. In the emergency department, ambulance prenotification and transport direct to the CT scanner are key elements that permit fast door to needle times for thrombolysis.

Mobile stroke units can improve stroke outcomes.

Mobile stroke units can improve stroke outcomes.

Mobile Stroke Units and Outcomes: Driving to Success?

In the past decade, several cities have offered acute stroke treatment with mobile stroke units (MSUs), in which an ambulance is equipped with a

Prospective, Multicenter, Controlled Trial of Mobile Stroke Units

BackgroundMobile stroke units (MSUs) are ambulances with staff and a computed tomographic scanner that may enable faster treatment with tissue plasminogen activator (t-PA) than standard management by emergency medical services (EMS). Whether and how much MSUs alter outcomes has not been extensively studied.MethodsIn an observational, prospective, multicenter, alternating-week trial, we assessed outcomes from MSU or EMS management within 4.5 hours after onset of acute stroke symptoms. The primary outcome was the score on the utility-weighted modified Rankin scale (range, 0 to 1, with higher scores indicating better outcomes according to a patient value system, derived from scores on the modified Rankin scale of 0 to 6, with higher scores indicating more disability). The main analysis involved dichotomized scores on the utility-weighted modified Rankin scale (≥0.91 or <0.91, approximating scores on the modified Rankin scale of ≤1 or >1) at 90 days in patients eligible for t-PA. Analyses were also performed in all enrolled patients.ResultsWe enrolled 1515 patients, of whom 1047 were eligible to receive t-PA; 617 received care by MSU and 430 by EMS. The median time from onset of stroke to administration of t-PA was 72 minutes in the MSU group and 108 minutes in the EMS group. Of patients eligible for t-PA, 97.1% in the MSU group received t-PA, as compared with 79.5% in the EMS group. The mean score on the utility-weighted modified Rankin scale at 90 days in patients eligible for t-PA was 0.72 in the MSU group and 0.66 in the EMS group (adjusted odds ratio for a score of ≥0.91, 2.43; 95% confidence interval [CI], 1.75 to 3.36; P<0.001). Among the patients eligible for t-PA, 55.0% in the MSU group and 44.4% in the EMS group had a score of 0 or 1 on the modified Rankin scale at 90 days. Among all enrolled patients, the mean score on the utility-weighted modified Rankin scale at discharge was 0.57 in the MSU group and 0.51 in the EMS group (adjusted odds ratio for a score of ≥0.91, 1.82; 95% CI, 1.39 to 2.37; P<0.001). Secondary clinical outcomes generally favored MSUs. Mortality at 90 days was 8.9% in the MSU group and 11.9% in the EMS group.ConclusionsIn patients with acute stroke who were eligible for t-PA, utility-weighted disability outcomes at 90 days were better with MSUs than with EMS. (Funded by the Patient-Centered Outcomes Research Institute; BEST-MSU ClinicalTrials.gov number, NCT02190500.)

High-resolution CT with arch/neck/head CT angiography on a mobile stroke unit

BackgroundMobile stroke units (MSUs) performance dependability and diagnostic yield of 16-slice, ultra-fast CT with auto-injection angiography (CTA) of the aortic arch/neck/circle of Willis has not been previously reported.MethodsWe performed a...

Improving Outcomes After Stroke: From Stroke Units to Mobile Stroke Units.

A proactive clinical approach to stroke care improved functional outcomes with implementation of specialized in-hospital stroke units, urgently delivered systemic thrombolysis, mechanical thrombectomy and most recently with mobile stroke units deployed in the field. An 18% absolute difference in outcomes as a shift across all modified Rankin Scale strata at 3 months in the recent Berlin study may not be explained by just 8.8% more patients treated within the golden hour for thrombolytic treatment from symptom onset. These findings parallel the findings in the largest controlled multi-center BEST-MSU trial (Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit) to date. A shortcoming in blinding of the investigators to the mode of transportation is similar to blinding to the endovascular treatment in PROBE (Prospective Randomized Open, Blinded End-Point) design used in thrombectomy trials. A faster access to stroke experts and brain imaging in the field for all patients suspect of stroke regardless symptom nature, severity, duration or resolution delivered by mobile stroke units is likely the reason for improved outcomes akin the impact observed in the initial multidisciplinary approach to in-hospital stroke units and reperfusion therapies delivery.

Application of Mobile Stroke Unit in Prehospital Thrombolysis of Acute Stroke: Experience from China

Background and Purpose: Most patients cannot receive intravenous thrombolytic therapy in the early stage of stroke onset, and the application of mobile stroke unit (MSU) in prehospital intravenous thrombolytic therapy of acute stroke may change this situation. The first MSU in China was put into use in 2017. Herein, we aimed to explore the preliminary experience of MSU in prehospital thrombolysis of acute stroke. Methods: Patients who received prehospital intravenous thrombolytic therapy using MSU were classified to the MSU thrombolysis group, and the control group consisted of stroke patients admitted by regular ambulances, who were transferred to hospital for intravenous thrombolytic therapy. The feasibility, safety, and duration of procedures were compared. Results: There were 14 patients received prehospital intravenous thrombolysis on the MSU, and 24 patients underwent intravenous thrombolysis in the emergency center, who were transferred by the ordinary ambulance during the same period. The median call-to-needle time was 59.5 min in the MSU thrombolysis group, while it was 89 min in the control group; the difference between the 2 groups was statistically significant (p = 0.001). The median time from onset to thrombolysis was 70 and 102.5 min, respectively, in the 2 groups (p = 0.002). The percentages of good clinical outcome (modified Rankin Scale score ≤ 2) at 90-day follow-up were 79 and 67%, respectively (p = 0.488). The rate of symptomatic intracranial hemorrhage and mortality during the perioperative period did not differ significantly between 2 groups. Conclusion: Despite the small sample size, our preliminary experience of the application of MSU in the prehospital thrombosis therapy seems to indicate a significant reduction in time from call to needle, the efficacy of MSU in the treatment of acute stroke needs further experiment and larger sample size to confirm.

Dosing Tissue Plasminogen Activator on a Mobile Stroke Unit: Comparison Between Estimated and Hospital-Measured Weights.

BACKGROUND: Prehospital tissue plasminogen activator dosing in a mobile stroke unit (MSU) is estimated by the paramedic and nurse. We aimed to determine the accuracy of the estimated weight method compared with the actual weight of patients treated with tissue plasminogen activator on the MSU. METHODS: We prospectively collected the estimated weight used on the MSU for treatment and the first-documented hospital-measured weight (bed scale) within 24 hours of hospital arrival. Median absolute and percent difference in weights were calculated; less than 10% of difference in weights was considered acceptable. To compare the estimated and measured weights, we conducted a Wilcoxon signed rank test and Fisher exact test to explore the association between weight difference of greater than 10% and patient outcomes. RESULTS: Among 337 patients, median estimated and hospital-measured weights were 79.0 kg (interquartile range [IQR], 66.0-94.5) and 78.5 kg (IQR, 65.0-91.7), respectively. The median of the absolute value of the difference in estimated versus measured weight was 2.7 kg (IQR, 0.6-7.6; P < .0001). The median percent difference in weight was 3.6% (IQR, 0.8%-9.4%). The median difference between the tissue plasminogen activator dosage administered on the MSU and the recommended dose based on the actual weight was 1.3 mg (IQR, 0.06-4.8) in absolute value. In 56 patients (16.6% of the entire sample) with overestimation of weight by greater than 10%, there were no symptomatic intracerebral hemorrhages. There was no association between weight difference and discharge modified Rankin score (P = .59). CONCLUSION: Weight estimation on an MSU can lead to similar tissue plasminogen activator dosing for 83.4% of subjects compared with if dosing were determined based on actual weight. Weight overestimation or underestimation had no detected impact on tissue plasminogen activator outcomes.

Reliability of Field Assessment Stroke Triage for Emergency Destination Scale Use by Paramedics: Mobile Stroke Unit First-Year Experience.

Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale is a helpful tool to triage patients with stroke in the field. However, data on its reliability in the prehospital setting are lacking. We aim to test the reliability of FAST-ED scale when used by paramedics in a mobile stroke unit covering a metropolitan area. As part of standard operating mobile stroke unit procedures, paramedics initially evaluated patients. If the event characterized a stroke alert, the FAST-ED score was determined by the paramedic upon patient contact (in-person) and then independently by a vascular neurologist (VN) immediately after paramedic evaluation (remotely/telemedicine). This allowed testing of the interrater agreement of the FAST-ED scoring performance between on-site prehospital providers and remotely located VN. Of a total of 238 patients transported in the first 15 months of the mobile stroke unit’s activity, 173 were included in this study. Median age was 63 (interquartile range, 55.5–75) years and 52.6% were females. A final diagnosis of ischemic stroke was made in 71 (41%), transient ischemic attack in 26 (15%), intracranial hemorrhage in 15 (9%), whereas 61 (35%) patients were stroke mimics. The FAST-ED scores matched perfectly among paramedics and VN in 97 (56%) instances, while there was 0 to 1-point difference in 158 (91.3%), 0 to 2-point difference in 171 (98.8%), and 3 or more point difference in 2 (1.1%) patients. The intraclass correlation between VN and paramedic FAST-ED scores showed excellent reliability, intraclass correlation coefficient 0.94 (95% CI, 0.92–0.96; P<0.001). When VN recorded FAST-ED score ≥3, paramedics also scored FAST-ED≥3 in majority of instances (63/71 patients; 87.5%). A large vessel occlusion was identified in 16 (9.2%) patients; 13 occlusions were identified with a FAST-ED≥3 while 3 were missed. All of the latter patients had National Institutes of Health Stroke Scale score ≤5. We demonstrate excellent reliability of FAST-ED scale performed by paramedics when compared with VN, indicating that it can be accurately performed by paramedics in the prehospital setting.

A Comparison of Time to Treatment between an Emergency Department Focused Stroke Protocol and Mobile Stroke Units.

San Francisco (California USA) is a relatively compact city with a population of 884,000 and nine stroke centers within a 47 square mile area. Emergency Medical Services (EMS) transport distances and times are short and there are currently no Mobile Stroke Units (MSUs). This study evaluated EMS activation to computed tomography (CT [EMS-CT]) and EMS activation to thrombolysis (EMS-TPA) times for acute stroke in the first two years after implementation of an emergency department (ED) focused, direct EMS-to-CT protocol entitled "Mission Protocol" (MP) at a safety net hospital in San Francisco and compared performance to published reports from MSUs. The EMS times were abstracted from ambulance records. Geometric means were calculated for MP data and pooled means were similarly calculated from published MSU data. From July 2017 through June 2019, a total of 423 patients with suspected stroke were evaluated under the MP, and 166 of these patients were either ultimately diagnosed with ischemic stroke or were treated as a stroke but later diagnosed as a stroke mimic. The EMS and treatment time data were available for 134 of these patients with 61 patients (45.5%) receiving thrombolysis, with mean EMS-CT and EMS-TPA times of 41 minutes (95% CI, 39-43) and 63 minutes (95% CI, 57-70), respectively. The pooled estimates for MSUs suggested a mean EMS-CT time of 35 minutes (95% CI, 27-45) and a mean EMS-TPA time of 48 minutes (95% CI, 39-60). The MSUs achieved faster EMS-CT and EMS-TPA times (P <.0001 for each). In a moderate-sized, urban setting with high population density, MP was able to achieve EMS activation to treatment times for stroke thrombolysis that were approximately 15 minutes slower than the published performance of MSUs.

Role of Telemedicine in Prehospital Stroke Care.

To summarize evidence for the feasibility and the efficacy of mobile stroke units (MSUs) and telemedicine in the field to reduce time delays in offering acute stroke interventions. A mobile stroke unit is a modified ambulance and includes sophisticated equipment, either trained personnel on board, or connection with skilled physicians via telemedicine. Stroke assessment and treatment agreeability between the on board and remote neurologist is high in MSUs. MSUs are the promising option to reduce stroke symptom onset to treatment time; telemedicine platform has a satisfactory audiovisual quality, high inter-rater reliability for remote stroke symptom assessment, diagnosis, and decision to treat. Use of MSU also avoids the need for inter-hospital transfers. MSUs improve prehospital stroke care and reduce delays in access to intravenous thrombolytic and mechanical thrombectomy in selective markets. Advancement in telecommunication and modern technology has the potential to make MSU telemedicine-aided management more cost-effective. Further research is needed before its widespread implementation.

Detection of Large Vessel Occlusion Stroke in the Prehospital Setting: Electroencephalography as a Potential Triage Instrument.

A reliable and fast instrument for prehospital detection of large vessel occlusion (LVO) stroke would be a game-changer in stroke care, because it would enable direct transportation of LVO stroke patients to the nearest comprehensive stroke center for endovascular treatment. This strategy would substantially improve treatment times and thus clinical outcomes of patients. Here, we outline our view on the requirements of an effective prehospital LVO detection method, namely: high diagnostic accuracy; fast application and interpretation; user-friendliness; compactness; and low costs. We argue that existing methods for prehospital LVO detection, including clinical scales, mobile stroke units and transcranial Doppler, do not fulfill all criteria, hindering broad implementation of these methods. Instead, electroencephalography may be suitable for prehospital LVO detection since in-hospital studies have shown that quantification of hypoxia-induced changes in the electroencephalography signal have good diagnostic accuracy for LVO stroke. Although performing electroencephalography measurements in the prehospital setting comes with challenges, solutions for fast and simple application of this method are available. Currently, the feasibility and diagnostic accuracy of electroencephalography in the prehospital setting are being investigated in clinical trials.

Pre-Hospital Diagnosis in Mobile Stroke Unit

ObjectivesMobile stroke unit (MSU) has been shown to rapidly provide pre-hospital thrombolysis in acute ischemic stroke (AIS). MSU encounters neurological disorders other than AIS that require emergent treatment. Methods/MaterialsWe obtained pre-hospital diagnosis and treatment data from the prospectively collected dataset on 221 consecutive MSU encounters. Based on initial clinical evaluation and neuroimaging obtained on MSU, the diagnosis of AIS (definite, probable, and possible AIS, transient ischemic attack), intracranial hemorrhage, and likely stroke mimics was made. ResultsFrom July 2014 to April 2015, 221 patients were treated on MSU. 78 (35%) patients had initial clinical diagnosis of definite/probable AIS or TIA, 69 (31%) were diagnosed as possible AIS or TIA, 15 (7%) had intracranial hemorrhage while 59 patients (27%) were diagnosed as likely stroke mimics. Stroke mimics encountered included 13 (6%) metabolic encephalopathy, 11 (5%) seizures, 9 (4%) migraines, 3 (1%) substance abuse, 2 (1%) CNS tumor, 3 (1%) infectious etiology and 3 (1%) hypoglycemia. Fifty-four (24%) patients received non-thrombolytic treatments on MSU ConclusionAbout one third of MSU encounters were not AIS initially, including intracranial hemorrhage and stroke mimics. MSU can be utilized to provide pre-hospital treatments in emergent neurological conditions other than AIS.

Impact of Time of Day on Time to Treatment in a Mobile Stroke Unit (5150)

Impact of Time of Day on Time to Treatment in a Mobile Stroke Unit (5150)

Hematoma Expansion in Patients Diagnosed with Intracranial Hemorrhage on Mobile Stroke Unit (4821)

Hematoma Expansion in Patients Diagnosed with Intracranial Hemorrhage on Mobile Stroke Unit (4821)