Montgomery County Hospital District EMS (MCHD) is collaborating with the South East Texas Regional Advisory Committee (SETRAC) to validate their existing prehospital suspected neurological event guideline for stroke assessment and transport. MCHD is a non-fire based EMS service in Montgomery County, Texas. We respond to approximately 58,000 calls to service and identify stroke in more than 500 patients per year. Our EMS system covers an estimated 1,100-square-mile service area and has 190 medics, 900 EMTs and 15 first responder (FR) organizations.
Acute ischemic stroke (AIS) is a debilitating and costly disease with few treatment options. On average in the U.S., a stroke occurs every 40 seconds and a death related to stroke every four minutes.1 To date, tissue plasminogen activator (Activase, or alteplase) has been the only FDA-approved treatment demonstrating improved clinical outcomes for AIS.2–5 There are compelling new data in carefully selected patients with large vessel occlusive (LVO) stroke that mechanical clot retrieval along with TPA may have a profound effect on the morbidity and mortality associated with AIS.6–9 It remains clear from the literature that timely care of acute ischemic stroke is associated with improved outcomes.6–9,10,11,15–18
Acute care coordination in stroke is a complex and challenging task that many health systems struggle to master. The American Stroke Association (ASA) recommendation for developing systems of stroke care emphasizes three main principles: effective communication among agencies, services and providers; an organized and standardized approach to acute stroke care at each facility; and performance feedback for continual improvement.14
EMS has a role in the all three of the aforementioned recommendations. Our first and most important role is making the correct diagnosis of stroke signs and symptoms. There are many EMS screening tools with high sensitivity for the identification of stroke, however most do not provide for severity and demonstrate poor sensitivity in distinguishing patients with LVO. Current practice consists of a four-part assessment of facial droop, speech arm strength and grip strength, along with severity indicators to assist in disposition decisions to primary vs. comprehensive stroke centers, per the SETRAC clinical guideline.
At present, we hypothesize our current practice is insensitive for diagnosis of LVO stroke. In this paper we report on our current clinical guideline and performance, along with a description of our Validation of Integrating a Stroke Algorithm (VISA) study where we will prospectively evaluate the clinical utility of a novel stroke score to diagnose LVO and disposition to an appropriate facility.
We conducted a retrospective quality data review of consecutive stroke alert patients from our ZOLL ePCR database from June 1, 2014 through March 29, 2016 (pre-VISA study period). This initial review focused on the number of strokes MCHD identified with the standardized SETRAC guideline by EMS personnel (see Figure 1), and stroke severity assessment to determine patient facility disposition decisions: primary stroke center or comprehensive stroke center (see Figure 2).
Figure 1: Stroke Identification
Figure 2: Stroke Severity
Figure 3: Rapid Arterial Occlusion Evaluation (RACE) Score
During this quality review period, a total of 792 stoke alerts interventions were activated within the MCHD EMS system. Of these, the National EMS Information System (NEMSIS) Primary Impression included the following:
- CVA stroke 626 (79%)
- Altered level of consciousness 70 (9%)
- Convulsion 17 (2%)
- Others 80 (10%)
SETRAC transport decision destinations of stroke patients were:
- Primary stroke center 464 (59%)
- Comprehensive stroke center 324 (41%)
- Unknown 4 (<1%)
Transport decisions were made using the SETRAC stoke severity guideline (Figure 2, without RACE score). The patient demographics included 426 (54%) female and the mean age was 68 years old (range 16–99).
In this patient population, our retrospective quality data prior to the use of the RACE score indicates that MCHD paramedics made transport decisions to comprehensive stroke centers in 41% of identified stroke cases based on the current SETRAC prehospital stroke identification and severity guidelines. The VISA follow-up study will evaluate the performance of RACE score for severe strokes/LVO when added to the current SETRAC tool. In this follow up study, we will collect data on patient disposition and clinical outcomes in order to fully evaluate the effectiveness of our novel algorithm.
At MCHD we use the SETRAC guideline on assessment and grading the severity of stroke in order to triage each case to the facility most capable of providing a proper level of care. Many centers are designated as primary stroke centers and can provide thrombolytic therapy within the 4.5 hour guideline. In contrast, a comprehensive stroke center is staffed with specialist neurosurgeons and neuro-interventional specialists capable of treating LVO with a combination of thrombolysis and mechanical retrieval therapy within a recommended onset-to-therapy (OTT) of less than six hours.
With the evolution of LVO therapy it became clear that we would need to validate our process in light of the new endovascular mechanical retrieval procedures available. We opted to stay with our current screening tool for stroke diagnosis and are currently evaluating our current severity score that aids us is triaging the most severe patients (hemorrhagic, LVOs) to the correct facility.
MCHD began conducting the VISA study May 1, 2016. We are collecting data on stroke diagnosis, disposition and clinical outcomes. Prior to implementation, all MCHD medics were trained (didactic/video recognition/testing) on stroke pathophysiology, diagnosis and assessment for stroke severity. During this session the RACE score will be demonstrated and performed by our medics. After May 1, MCHD medics will assess RACE score along with our current SETRAC-based protocol. We will prospectively collect data to validate our current process and examine the sensitivity of the RACE stroke-screening tool for hospital diagnosis of LVO.
After May 1, MCHD will add the RACE evaluation scale and will modify our existing stroke severity work flow to include RACE greater than or equal to five stroke scale. The RACE score will allow MCHD EMS to utilize a validated prehospital stroke severity criteria assessment scale and evaluate the calculated score as a predictive tool for LVO. All patients identified and included as acute stroke will be followed up for protocol adherence, triage accuracy (proper/under/over triage), admitting diagnosis, transfers, times to therapy and clinical outcomes.
From the most recent studies on mechanical therapy for LVO, time appears to be a critical component with diminishing clinical returns as OTT times increase. These trials all demonstrated a streamlined care coordination process with impressive door-to-therapy times.6–9 The SWIFT PRIME clinical trials (solitaire with the intention for thrombectomy as primary endovascular treatment) had a goal of CT to groin puncture in less than 70 minutes and median time of arrival in ED to groin puncture of 90 minutes.9 These times to reperfusion therapy represent a difficult target for most institutions with their current processes. Acute care coordination strategies—whether cognitive, Get with the Guidelines (GWTG) or mobile apps—have demonstrated success in improving these difficult-to-reach goals and may play an important role in the ultimate success of this novel therapy for AIS.11–13, 19
There are data to suggest that comprehensive care coordination initiatives or use of mobile care coordination technology that conform to the ASA recommendations may improve door-to-needle (DTN) performance. In a large multicenter study that looked at the effect of GWTG care coordination/quality improvement initiative in a before and after cohort of 71,000 patients treated with TPA for AIS, only 26% in the pre-intervention arm were treated within 60 minutes of arrival. This study demonstrated a 15% improvement in DTN after GWTG was introduced with an improvement in DTN < 60 minutes of 15% (26–41%). The improvement in DTN performance was associated with improved in-hospital mortality, less intracranial hemorrhage and more patients discharged home.11 In contrast to the GWTG care coordination initiative, the use of mobile technologies from Pulsara—Stop Stroke and Stop STEMI—have shown promising improvements of up to 46% in door-to -therapy times in STEMI and AIS.12, 13,19
It is clear that acute stroke care is rapidly evolving and EMS is going to play a huge role in the clinical outcomes of these patients. It is critical that we now go a step further in our differential for stroke to tease out the patients with likely LVO that would benefit from a comprehensive stroke center.
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