Prehospital thrombolysis: a manual from Berlin

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.

Functional stroke outcomes after mobile stroke unit deployment - the revised protocol for the Berlin Prehospital Or Usual Delivery of acute stroke care (B_PROUD) part 2 study

Background

Studies investigating the Mobile Stroke Unit (MSU) concept have shown increased thrombolysis rates, reduced alarm-to-treatment times and improved prehospital triage. Yet, so far, there is no definite scientific proof of better functional outcome after MSU deployment compared to regular ambulances.

Methods

We provide a revised protocol for the second part of the B_PROUD trial as organization of the MSU dispatch did not meet the anticipated standards in the first part. B_PROUD is a pragmatic, prospective study comparing functional outcomes of treatment candidates with or without MSU care. Treatment candidates are defined as patients with a final diagnosis of ischemic stroke or transient ischemic attack, onset-to-dispatch-times ≤4 h, disabling symptoms not resolved at time of ambulance arrival, and the ability to ambulate prior to the qualifying event. These patients are included if their emergency call prompted a stroke alarm at the dispatch center during MSU operation hours (7 am–11 pm, Monday-Sunday) and if the emergency is located within the MSU operation area in Berlin, Germany. The intervention group consists of patients who are cared for by the MSU. When the MSU is already in operation for another emergency, MSU dispatches are handled by regular ambulances (about 45%). These dispatches create the control group. Blinded stroke physicians assess the modified Rankin Scale (mRS) score in recorded structured interviews 3 months after stroke. The primary outcome is the degree of disability and death over the full range of the mRS. As a change to the previously published protocol and only pertinent in case of more than 9% lost-to-follow-up, a co-primary outcome was introduced consisting of the proportions of death, new institutional care or severe disability in patients with additional use of information from registration offices.

Perspective

The results will inform parties involved in acute stroke care organization on the effectiveness of the MSU concept.

Trial registration

The protocol is registered in (NCT03931616) and has been approved by the ethical review committee of the Charité – University Medicine Berlin (EA4/109/15) on September 2, 2015. The study protocol of B_PROUD part 1 had been published in the International Journal of Stroke as “Berlin Prehospital Or Usual Delivery of acute stroke care (B_PROUD) – study protocol” (doi: 10.1177/1747493017700152) on March 22, 2017 [1] previous to first patient’s registration.

A History of Mobile Stroke Units and Review of Literature

Using intravenous tissue plasminogen activator (IV tPA), improved functional outcomes are seen with earlier initiation of treatment. Recent studies have shown endovascular revascularization to be a revolutionary and effective treatment. There have been many initiatives focused on improving public education and awareness of stroke symptoms. The concept of a mobile stroke unit (MSU) was created as a way of bringing treatment to patients. Earlier CT scans, delivery of tPA, proper triage and on-scene goal-directed care were the primary goals with these units. It was thought that rapid implementation would shorten hospital stay and improve outcomes. The University of Saarland found a decrease of 41 minutes from stroke alarm to therapeutic decision when an MSU was used. A second trial found a decrease of 25 minutes in time to treatment, an increase in the rate of thrombolysis utilization, and no change in the rates of intracranial hemorrhage or 7-day mortality when an MSU was employed. In 2016, a Lancet article showed that 3 month modified Rankin Scale (mRS) and 3-month mortality were improved in MSU patients. Finally, starting thrombolytic therapy in the MSU was associated with higher probability of mRS of 0-3 but not an improved 3-month survival rate. Long-term results are thus far not available precluding an effective cost-benefit analysis. Many study results are not generalizable as they compare a single hospital system and specialized MSU team to conventional care delivered by a multiple healthcare systems. Future studies will target these limitations.

Setting Up a Stroke Team Algorithm and Conducting Simulation-based Training in the Emergency Department - A Practical Guide

Time is of the essence when caring for an acute stroke patient. The ultimate goal is to restore blood flow to the ischemic brain. This can be achieved by either thrombolysis with recombinant tissue-plasminogen activator (rt-PA), the standard therapy for stroke patients who present within the first hours of symptom onset without contraindications, or by an endovascular approach, if a proximal brain vessel occlusion is detected. As the efficacy of both therapies declines over time, every minute saved along the way will improve the patient's outcome. This critical situation requires thorough work and precise communication with the patient, the family and colleagues from different professions to acquire all relevant information and reach the right decision while carefully monitoring the patient. This is a high fidelity situation. In nonmedical high-fidelity environments such as aviation, Crew Resource Management (CRM) is used to enhance safety and team efficiency. This guide shows how a Stroke Team algorithm, which is transferable to other hospital settings, was established and how regular simulation-based trainings were performed. It requires determination and endurance to maintain these time-consuming simulation trainings on a regular basis over the course of time. However, the resulting improvement of team spirit and excellent door-to-needle times will benefit both the patients and the work environment in any hospital. A dedicated Stroke Team of 7 persons who are notified 24/7 by a collective call via speed dial and run a binding algorithm that takes approximately 20 min, was established. To train everybody involved in this algorithm, a simulation-based team training for all new Stroke Team members was conceived and conducted at monthly intervals. This led to a relevant and sustained reduction of the mean door-to-needle time to 25 min, and enhanced the feeling of stroke readiness especially in junior doctors and nurses.

Lateral Chronic Cranial Window Preparation Enables In Vivo Observation Following Distal Middle Cerebral Artery Occlusion in Mice

Focal cerebral ischemia (i.e., ischemic stroke) may cause major brain injury, leading to a severe loss of neuronal function and consequently to a host of motor and cognitive disabilities. Its high prevalence poses a serious health burden, as stroke is among the principal causes of long-term disability and death worldwide¹. Recovery of neuronal function is, in most cases, only partial. So far, treatment options are very limited, in particular due to the narrow time window for thrombolysis^2,3. Determining methods to accelerate recovery from stroke remains a prime medical goal; however, this has been hampered by insufficient mechanistic insights into the recovery process. Experimental stroke researchers frequently employ rodent models of focal cerebral ischemia. Beyond the acute phase, stroke research is increasingly focused on the sub-acute and chronic phase following cerebral ischemia. Most stroke researchers apply permanent or transient occlusion of the MCA in mice or rats. In patients, occlusions of the MCA are among the most frequent causes of ischemic stroke⁴. Besides proximal occlusion of the MCA using the filament model, surgical occlusion of the distal MCA is probably the most frequently used model in experimental stroke research⁵. Occlusion of a distal (to the branching of the lenticulo-striate arteries) MCA branch typically spares the striatum and primarily affects the neocortex. Vessel occlusion can be permanent or transient. High reproducibility of lesion volume and very low mortality rates with respect to the long-term outcome are the main advantages of this model. Here, we demonstrate how to perform a chronic cranial window (CW) preparation lateral to the sagittal sinus, and afterwards how to surgically induce a distal stroke underneath the window using a craniotomy approach. This approach can be applied for sequential imaging of acute and chronic changes following ischemia via epi-illuminating, confocal laser scanning, and two-photon intravital microscopy.

Acute Stroke: Current Evidence-based Recommendations for Prehospital Care

Introduction

In the United States, emergency medical services (EMS) protocols vary widely across jurisdictions. We sought to develop evidence-based recommendations for the prehospital evaluation and treatment of a patient with a suspected stroke and to compare these recommendations against the current protocols used by the 33 EMS agencies in the state of California.

Methods

We performed a literature review of the current evidence in the prehospital treatment of a patient with a suspected stroke and augmented this review with guidelines from various national and international societies to create our evidence-based recommendations. We then compared the stroke protocols of each of the 33 EMS agencies for consistency with these recommendations. The specific protocol components that we analyzed were the use of a stroke scale, blood glucose evaluation, use of supplemental oxygen, patient positioning, 12-lead electrocardiogram (ECG) and cardiac monitoring, fluid assessment and intravenous access, and stroke regionalization.

Results

Protocols across EMS agencies in California varied widely. Most used some sort of stroke scale with the majority using the Cincinnati Prehospital Stroke Scale (CPSS). All recommended the evaluation of blood glucose with the level for action ranging from 60 to 80mg/dL. Cardiac monitoring was recommended in 58% and 33% recommended an ECG. More than half required the direct transport to a primary stroke center and 88% recommended hospital notification.

Conclusion

Protocols for a patient with a suspected stroke vary widely across the state of California. The evidence-based recommendations that we present for the prehospital diagnosis and treatment of this condition may be useful for EMS medical directors tasked with creating and revising these protocols.

Brain imaging in acute ischemic stroke—MRI or CT?

In acute stroke, imaging provides different technologies to demonstrate stroke subtype, tissue perfusion and vessel patency. In this review, we highlight recent clinical studies that are likely to guide therapeutic decisions. Clot length in computed tomography (CT) and clot burden in MR, imaging of leptomeningeal collaterals and indicators for active bleeding are illustrated. Imaging-based concepts for treatment of stroke at awakening and pre-hospital treatment in specialized ambulances offer new potentials to improve patient outcome.

Imaging of prehospital stroke therapeutics

Despite significant quality improvement efforts to streamline in-hospital acute stroke care in the conventional model, there remain inherent layers of treatment delays, which could be eliminated with prehospital diagnostics and therapeutics administered in a mobile stroke unit. Early diagnosis using telestroke and neuroimaging while in the ambulance may enable targeted routing to hospitals with specialized care, which will likely improve patient outcomes. Key clinical trials in telestroke, mobile stroke units with prehospital neuroimaging capability, prehospital ultrasound and co-administration of various classes of neuroprotectives, antiplatelets and antithrombin agents with intravenous thrombolysis are discussed in this article.

Strategies for streamlining emergency stroke care

There has been a tremendous evolution in the stroke systems of care in the USA. Public awareness, prehospital care, and in-hospital protocols have never been so effectively connected. However, given the critical role of time to effective reperfusion in the setting of acute ischemic stroke, it is vital and timely to implement strategies to further streamline emergency stroke care. This article reviews the most current standards and guidelines related to the flow of stroke care in the prehospital and emergency settings.