Stroke severity quantification by critical care physicians in a mobile stroke unit

Experiences from a cluster-randomized trial (ParaNASPP) exploring triage and diagnostic accuracy in paramedic-suspected stroke: a qualitative interview study

BACKGROUND AND PURPOSE

Timely prehospital stroke recognition was explored in the Paramedic Norwegian Acute Stroke Prehospital Project (ParaNASPP) by implementation of stroke education for paramedics and use of the National Institutes of Health Stroke Scale (NIHSS) through a mobile application. The study tested triage and facilitated communication between paramedics and stroke physicians. To complement the quantitative results of the clinical trial, a qualitative approach was used to identify factors that influence triage decisions and diagnostic accuracy in prehospital stroke recognition experienced by paramedics and stroke physicians.

METHOD

Semi-structured qualitative individual interviews were performed following an interview guide. Informants were recruited from the enrolled paramedics and stroke physicians who participated in the ParaNASPP trial from Oslo University Hospital. Interviews were audio recorded, transcribed verbatim and approached inductively using the principles of thematic analysis.

RESULTS

Fourteen interviews were conducted, with seven paramedics and seven stroke physicians. Across both groups two overarching themes were identified related to triage decisions and diagnostic accuracy in prehospital stroke recognition: prehospital NIHSS reliably improves clinical assessment and communication quality; overtriage is widely accepted whilst undertriage is not.

CONCLUSION

Paramedics and stroke physicians described how prehospital NIHSS improved communication quality and reliably improved prehospital clinical assessment. The qualitative results support a rationale of an application algorithm to decide which NIHSS items should prompt immediate prenotification rather than a complete NIHSS as default.

Addressing Disparities in Acute Stroke Management and Prognosis

There are now abundant data demonstrating disparities in acute stroke management and prognosis; however, interventions to reduce these disparities remain limited. This special report aims to provide a critical review of the current landscape of disparities in acute stroke care and highlight opportunities to use implementation science to reduce disparities throughout the early care continuum. In the prehospital setting, stroke symptom recognition campaigns that have been successful in reducing prehospital delays used a multilevel approach to education, including mass media, culturally tailored community education, and professional education. The mobile stroke unit is an organizational intervention that has the potential to provide more equitable access to timely thrombolysis and thrombectomy treatments. In the hospital setting, interventions to address implicit biases among health care providers in acute stroke care decision-making are urgently needed as part of a multifaceted approach to advance stroke equity. Implementing stroke systems of care interventions, such as evidence-based stroke care protocols at designated stroke centers, can have a broader public health impact and may help reduce geographic, racial, and ethnic disparities in stroke care, although further research is needed. The long-term impact of disparities in acute stroke care cannot be underestimated. The consistent trend of longer time to treatment for Black and Hispanic people experiencing stroke has direct implications on long-term disability and independence after stroke. A learning health system model may help expedite the translation of evidence-based interventions into clinical practice to reduce disparities in stroke care.

Inter-Rater Agreement on Cincinnati Prehospital Stroke Scale (CPSS) and Prehospital Acute Stroke Severity Scale (PASS) Between EMS Providers, Neurology Residents and Neurology Consultants

Objective

To examine the agreement between emergency medical service (EMS) providers, neurology residents and neurology consultants, using the Cincinnati Prehospital Stroke Scale (CPSS) and the Prehospital Acute Stroke Severity Scale (PASS).

Methods

Patients with stroke, transient ischemic attack (TIA) and stroke mimic were included upon primary stroke admission or during rehabilitation. Patients were included from June 2018 to September 2019. Video recordings were made of patients being assessed with CPSS and PASS. The recordings were later presented to the healthcare professionals. To determine relative and absolute interrater reliability in terms of inter-rater agreement (IRA), we used generalisability theory. Group-level agreement was determined against a gold standard and presented as an area under the curve (AUC). The gold standard was a consensus agreement between two neurology consultants.

Results

A total of 120 patient recordings were assessed by 30 EMS providers, two neurology residents and two neurology consultants. Using the CPSS and the PASS, a total of 1,800 assessments were completed by EMS providers, 240 by neurology residents and 240 by neurology consultants. The overall relative and absolute IRA for all items combined from the CPSS and PASS score was 0.84 (95% CI 0.80; 0.87) and 0.81 (95% CI 0.77; 0.85), respectively. Using the CPSS, the agreement on a group-level resulted in AUCs of 0.83 (95% CI 0.78; 0.88) for the EMS providers and 0.86 (95% CI 0.82; 0.90) for the neurology residents when compared with the gold standard. Using the PASS, the AUC was 0.82 (95% CI 0.77; 0.87) for the EMS providers and 0.88 (95% CI 0.84; 0.93) for the neurology residents.

Conclusion

The high relative and absolute inter-rater agreement underpins a high robustness/generalisability of the two scales. A high agreement exists across individual raters and different groups of healthcare professionals supporting widespread applicability of the stroke scales.

Quantification of amyloid PET for future clinical use: a state-of-the-art review

Amyloid-β (Aβ) pathology is one of the earliest detectable brain changes in Alzheimer's disease (AD) pathogenesis. The overall load and spatial distribution of brain Aβ can be determined in vivo using positron emission tomography (PET), for which three fluorine-18 labelled radiotracers have been approved for clinical use. In clinical practice, trained readers will categorise scans as either Aβ positive or negative, based on visual inspection. Diagnostic decisions are often based on these reads and patient selection for clinical trials is increasingly guided by amyloid status. However, tracer deposition in the grey matter as a function of amyloid load is an inherently continuous process, which is not sufficiently appreciated through binary cut-offs alone. State-of-the-art methods for amyloid PET quantification can generate tracer-independent measures of Aβ burden. Recent research has shown the ability of these quantitative measures to highlight pathological changes at the earliest stages of the AD continuum and generate more sensitive thresholds, as well as improving diagnostic confidence around established binary cut-offs. With the recent FDA approval of aducanumab and more candidate drugs on the horizon, early identification of amyloid burden using quantitative measures is critical for enrolling appropriate subjects to help establish the optimal window for therapeutic intervention and secondary prevention. In addition, quantitative amyloid measurements are used for treatment response monitoring in clinical trials. In clinical settings, large multi-centre studies have shown that amyloid PET results change both diagnosis and patient management and that quantification can accurately predict rates of cognitive decline. Whether these changes in management reflect an improvement in clinical outcomes is yet to be determined and further validation work is required to establish the utility of quantification for supporting treatment endpoint decisions. In this state-of-the-art review, several tools and measures available for amyloid PET quantification are summarised and discussed. Use of these methods is growing both clinically and in the research domain. Concurrently, there is a duty of care to the wider dementia community to increase visibility and understanding of these methods.

Cost-Effectiveness of Mobile Stroke Unit Care in Norway

BACKGROUND:

Acute ischemic stroke treatment in mobile stroke units (MSUs) reduces time-to-treatment and increases thrombolytic rates, but implementation requires substantial investments. We wanted to explore the cost-effectiveness of MSU care incorporating novel efficacy data from the Norwegian MSU study, Treat-NASPP (the Norwegian Acute Stroke Prehospital Project).

METHODS:

We developed a Markov model linking improvements in time-to-treatment and thrombolytic rates delivered by treatment in an MSU to functional outcomes for the patients in a lifetime perspective. We estimated incremental costs, health benefits, and cost-effectiveness of MSU care as compared with conventional care. In addition, we estimated a minimal MSU utilization level for the intervention to be cost-effective in the publicly funded health care system in Norway.

RESULTS:

MSU care was associated with an expected quality-adjusted life-year-gain of 0.065 per patient, compared with standard care. Our analysis suggests that about 260 patients with ischemic stroke need to be treated with MSU annually to result in an incremental cost-effectiveness ratio of about NOK385 000 (US$43 780) per quality-adjusted life-year for MSU compared with standard care. The incremental cost-effectiveness ratio varies between some NOK1 000 000 (US$113 700) per quality-adjusted life-year if an MSU treats 100 patients per year and to about NOK340 000 (US$38 660) per quality-adjusted life-year if 300 patients with acute ischemic stroke are treated.

CONCLUSIONS:

MSU care in Norwegian settings is potentially cost-effective compared with conventional care, but this depends on a relatively high annual number of treated patients with acute ischemic stroke per vehicle. These results provide important information for MSU implementation in government-funded health care systems.

Utility of the AM-PAC "6 Clicks" Basic Mobility and Daily Activity Short Forms to Determine Discharge Destination in an Acute Stroke Population

IMPORTANCE

The American Heart Association and American Stroke Association recommend early identification of level of rehabilitative care as a priority after stroke.

OBJECTIVE

To evaluate the utility of the Activity Measure for Post-Acute Care (AM-PAC) "6 Clicks" Daily Activity and Basic Mobility forms to determine the next level of rehabilitation after hospitalization for adults with stroke.

DESIGN

Retrospective cohort design using medical records from 2015 to 2016.

SETTING

Major urban hospital.

PARTICIPANTS

Patients admitted to the stroke service, with a confirmed stroke, who were seen by a physical or occupational therapist; who had a 6 Clicks Basic Mobility or Daily Activity score at initial evaluation; and who were discharged to home, an acute inpatient rehabilitation facility (IRF), or a subacute skilled nursing facility (SNF).

OUTCOMES AND MEASURES

Length of stay and discharge destination.

RESULTS

Seven hundred four participants (M age = 68.28 yr; 51.21% female) were included. Analysis of variance and receiver operating characteristic curves were performed. Daily Activity scores were highest for home discharge, lower for IRF discharge, and lowest for SNF discharge; Basic Mobility showed a similar pattern. Cutoff values distinguishing home from further inpatient rehabilitation were 44.50 for Basic Mobility and 39.40 for Daily Activity scores (area under the curve [AUC] = .82 for both forms), with scores of 34.59 (AUC = 0.64) and 31.32 (AUC = 0.67) separating IRF from SNF, respectively.

CONCLUSIONS AND RELEVANCE

Therapists should incorporate 6 Clicks scores into their discharge planning. What This Article Adds: This research demonstrates the utility of an outcome measure in the acute care setting that assists in planning discharge destination for patients with stroke.

The Mobile Stroke Unit Nurse: An International Exploration of Their Scope of Practice, Education, and Training

ABSTRACT

BACKGROUND: Mobile stroke units (MSUs) are ambulance-based prehospital stroke care services. Through immediate roadside assessment and onboard brain imaging, MSUs provide faster stroke management with improved patient outcomes. Mobile stroke units have enabled the development of expanded scope of practice for stroke nurses; however, there is limited published evidence about these evolving prehospital acute nursing roles. AIMS: The aim of this study was to explore the expanded scope of practice of nurses working on MSUs by identifying MSUs with onboard nurses; describing the roles and responsibilities, training, and experience of MSU nurses, through a search of the literature; and describing 2 international MSU services incorporating nurses from Memphis, Tennessee, and Melbourne, Australia. METHODS: We searched PubMed, CINAHL, and the Joanna Briggs Institute Evidence-Based Practice database using the terms "mobile stroke unit" and "nurse." Existing MSUs were identified through the PRE-hospital Stroke Treatment Organization to determine models that involved nurses. We describe 2 MSUs involving nurses: one in Memphis and one in Melbourne, led by 2 of our authors. RESULTS: Ninety articles were found describing 15 MSUs; however, staffing details were lacking, and it is unknown how many employ nurses. Nine articles described the role of the nurse, but role specifics, training, and expertise were largely undocumented. The MSU in Memphis, the only unit to be staffed exclusively by onboard nurse practitioners, is supported by a neurologist who consults via telephone. The Melbourne MSU plans to trial a nurse-led telemedicine model in the near future. CONCLUSION: We lack information on how many MSUs employ nurses, and the nurses' scope of practice, training, and expertise. Expert stroke nurse practitioners can safely perform many of the tasks undertaken by the onboard neurologist, making a nurse-led telemedicine model an effective and potentially cost-effective model that should be considered for all MSUs.

Streamlining Acute Stroke Care by Introducing National Institutes of Health Stroke Scale in the Emergency Medical Services: A Prospective Cohort Study

National Institutes of Health Stroke Scale (NIHSS) is the most validated clinical scale for stroke recognition, severity grading, and symptom monitoring in acute care and hospital settings. Numerous modified prehospital stroke scales exist, but these scales contain less clinical information and lack compatibility with in-hospital stroke scales. In this real-life study, we aimed to investigate if NIHSS conducted by paramedics in the field is a feasible and accurate prehospital diagnostic tool.

Mobile Stroke Units: Current Evidence and Impact

PURPOSE OF REVIEW

Several approaches have been developed to optimize prehospital systems for acute stroke given poor access and significant delays to timely treatment. Specially equipped ambulances that directly initiate treatment, known as Mobile Stroke Units (MSUs), have rapidly proliferated across the world. This review provides a comprehensive summary on the efficacy of MSUs in acute stroke, its various applications beyond thrombolysis, as well as the establishment, optimal setting and cost-effectiveness of incorporating an MSU into healthcare systems.

RECENT FINDINGS

MSUs speed stroke treatment into the first "golden hour" when better outcomes from thrombolysis are achieved. While evidence for the positive impact of MSUs on outcomes was previously unavailable, two recent landmark controlled trials, B_PROUD and BEST-MSU, show that MSUs result in significantly lesser disability compared to conventional ambulance care. Emerging literature prove the significant impact of MSUs. Adaptability however remains limited by significant upfront financial investment, challenges with reimbursements and pending evidence on their cost-effectiveness.

Paramedic Norwegian Acute Stroke Prehospital Project (ParaNASPP) study protocol: a stepped wedge randomised trial of stroke screening using the National Institutes of Health Stroke Scale in the ambulance

Background

Less than 50% of stroke patients in Norway reach hospital within 4 h of symptom onset. Early prehospital identification of stroke and triage to the right level of care may result in more patients receiving acute treatment. Quality of communication between paramedics and the stroke centre directly affects prehospital on-scene time, emphasising this as a key factor to reduce prehospital delay. Prehospital stroke scales are developed for quick and easy identification of stroke, but have poor sensitivity and specificity compared to an in-hospital assessment with the National Institutes of Health Stroke Scale (NIHSS). The aim of the Paramedic Norwegian Acute Stroke Prehospital Project (ParaNASPP) is to assess whether a structured learning program, prehospital NIHSS and a mobile application facilitating communication with the stroke physician may improve triage of acute stroke patients.

Methods

A stepped wedge cluster randomised controlled intervention design will be used in this trial in Oslo, Norway. Paramedics at five ambulance stations will enrol adult patients with suspected stroke within 24 h of symptom onset. All paramedics will begin in a control phase with standard procedures. Through an e-learning program and practical training, a random and sequential switch to the intervention phase takes place. A mobile application for NIHSS scoring, including vital patient information for treatment decisions, transferring data from paramedics to the on-call stroke physician at the Stroke Unit at Oslo University Hospital, will be provided for the intervention.

The primary outcome measure is positive predictive value (PPV) for prehospital identification of patients with acute stroke defined as the proportion of patients accepted for stroke evaluation and discharged with a final stroke diagnosis. One thousand three hundred patients provide a 50% surplus to the 808 patients needed for 80% power to detect a 10% increase in PPV.

Discussion

Structured and digital communication using a common scale like NIHSS may result in increased probability for better identification of stroke patients and less stroke mimics delivered to a stroke team for acute diagnostics and treatment in our population.

Trial registration

ClinicalTrials.govNCT04137874. Registered on October 24, 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06006-4.

Ultraearly thrombolysis by an anesthesiologist in a mobile stroke unit: A prospective, controlled intervention study

BACKGROUND

Acute stroke treatment in mobile stroke units (MSU) is feasible and reduces time-to-treatment, but the optimal staffing model is unknown. We wanted to explore if integrating thrombolysis of acute ischemic stroke (AIS) in an anesthesiologist-based emergency medical services (EMS) reduces time-to-treatment and is safe.

METHODS

A nonrandomized, prospective, controlled intervention study.

INCLUSION CRITERIA

age ≥18 years, nonpregnant, stroke symptoms with onset ≤4 h. The MSU staffing is inspired by the Norwegian Helicopter Emergency Medical Services crew with an anesthesiologist, a paramedic-nurse and a paramedic. Controls were included by conventional ambulances in the same catchment area. Primary outcome was onset-to-treatment time. Secondary outcomes were alarm-to-treatment time, thrombolytic rate and functional outcome. Safety outcomes were symptomatic intracranial hemorrhage and mortality.

RESULTS

We included 440 patients. MSU median (IQR) onset-to-treatment time was 101 (71-155) minutes versus 118 (90-176) minutes in controls, p = 0.007. MSU median (IQR) alarm-to-treatment time was 53 (44-65) minutes versus 74 (63-95) minutes in controls, p < 0.001. Golden hour treatment was achieved in 15.2% of the MSU patients versus 3.7% in the controls, p = 0.005. The thrombolytic rate was higher in the MSU (81% vs 59%, p = 0.001). MSU patients were more often discharged home (adjusted OR [95% CI]: 2.36 [1.11-5.03]). There were no other significant differences in outcomes.

CONCLUSIONS

Integrating thrombolysis of AIS in the anesthesiologist-based EMS reduces time-to-treatment without negatively affecting outcomes. An MSU based on the EMS enables prehospital assessment of acute stroke in addition to other medical and traumatic emergencies and may facilitate future implementation.

Impact of mobile stroke units

Since its first introduction in clinical practice in 2008, the concept of mobile stroke unit enabling prehospital stroke treatment has rapidly expanded worldwide. This review summarises current knowledge in this young field of stroke research, discussing topics such as benefits in reduction of delay before treatment, vascular imaging-based triage of patients with large-vessel occlusion in the field, differential blood pressure management or prehospital antagonisation of anticoagulants. However, before mobile stroke units can become routine, several questions remain to be answered. Current research, therefore, focuses on safety, long-term medical benefit, best setting and cost-efficiency as crucial determinants for the sustainability of this novel strategy of acute stroke management.

Prehospital Identification of Large Vessel Occlusions Using Modified National Institutes of Health Stroke Scale: A Pilot Study

Stroke identification is a key step in acute ischemic stroke management. Our objectives were to prospectively examine the agreement between prehospital and hospital Modified National Institutes of Health Stroke Scale (mNIHSS) assessments as well as assess the prehospital performance characteristics of the mNIHSS for identification of large vessel occlusion strokes.

Method: In this prospective cohort study conducted over a 20-month period (11/2016–6/2018), we trained 40 prehospital providers (paramedics) in Emergency Neurological Life Support (ENLS) curriculum and in mNIHSS. English-speaking patients aged 18 and above transported for an acute neurological deficit were included. Using unique identifiers, we linked the prehospital assessment records to the hospital record. We calculated the agreement between prehospital and hospital mNIHSS scores using the Bland-Altman analysis and the sensitivity and specificity of the prehospital mNIHSS.

Results: Of the 31 patients, the mean difference (prehospital mNIHSS—hospital mNIHSS) was 2.4, 95% limits of agreement (−5.2 to 10.0); 10 patients (32%) met our a priori imaging definition of large vessel occlusion and the sensitivity of mNIHSS ≥ 8 was 6/10 or 0.60 (95% CI: 0.26–0.88) and the specificity was 13/21 or 0.62 (95% CI: 0.38–0.82), respectively.

Conclusions: We were able to train prehospital providers to use the prehospital mNIHSS. Prehospital and hospital mNIHSS had a reasonable level of agreement and and the scale was able to predict large vessel occlusions with moderate sensitivity.

Effect of off-hour versus work-hour thrombolysis for acute ischemic stroke on emergency department patients' outcome: a retrospective study

OBJECTIVE

Early management of patients with acute ischemic stroke is crucial regardless of the time of presentation. The aim of the study was to evaluate the effect of off-hours management of patients with ischemic stroke that underwent thrombolytic therapy in the emergency department.

METHODS

This is a single-center retrospective study included ischemic stroke patients who received thrombolysis in the emergency department from January 2009 to April 2017. Patients who presented between 08:00 and 17:00 Monday to Friday were in the 'work-hour group (group 1)' versus others who were considered 'off-hours (group 2)'. Primary endpoint was 3-month mortality. Secondary endpoints included the National Institutes of Health Stroke Scale and dramatic recovery rate at 24 h, intracranial hemorrhage, systemic hemorrhage and modified Rankin Scale at the 3 months. Symptom-to-needle time, door-to-computed tomography time, and door-to-needle time were also compared between groups.

RESULTS

A total of 399 ischemic stroke patients were included in the analysis, 137 (34%) during work-hours and 262 (66%) during off-hours. The mortality rate was not different at 3 months between groups: 24 (17.5%) in the work-hours group versus 38 (14.5%) in the off-hours group [odds ratio 1.25; 95% confidence interval (CI), 0. 72-2.19]. There were no differences between groups on secondary endpoints. The mean time of symptom-to-needle was significantly higher during off-hours (mean difference: 18.4 min; 95% CI, 7.81-29.0).

CONCLUSIONS

In this study, there were no significant differences in mortality and functional outcomes at 3 months between patients who underwent off-hour or work-hour thrombolysis in the emergency department.

Detailed severity assessment of Cincinnati Prehospital Stroke Scale to detect large vessel occlusion in acute ischemic stroke

Background

Selecting stroke patients with large vessel occlusion (LVO) based on prehospital stroke scales could provide a faster triage and transportation to a comprehensive stroke centre resulting a favourable outcome. We aimed here to explore the detailed severity assessment of Cincinnati Prehospital Stroke Scale (CPSS) to improve its ability to detect LVO in acute ischemic stroke (AIS) patients.

Methods

A cross-sectional analysis was performed in a prospectively collected registry of consecutive patients with first ever AIS admitted within 6 h after symptom onset. On admission stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) and the presence of LVO was confirmed by computed tomography angiography (CTA) as an endpoint. A detailed version of CPSS (d-CPSS) was designed based on the severity assessment of CPSS items derived from NIHSS. The ability of this scale to confirm an LVO was compared to CPSS and NIHSS respectively.

Results

Using a ROC analysis, the AUC value of d-CPSS was significantly higher compared to the AUC value of CPSS itself (0.788 vs. 0.633, p < 0.001) and very similar to the AUC of NIHSS (0.795, p = 0.510). An optimal cut-off score was found as d-CPSS≥5 to discriminate the presence of LVO (sensitivity: 69.9%, specificity: 75.2%).

Conclusion

A detailed severity assessment of CPSS items (upper extremity weakness, facial palsy and speech disturbance) could significantly increase the ability of CPSS to discriminate the presence of LVO in AIS patients.

Improving Prehospital Stroke Services in Rural and Underserved Settings With Mobile Stroke Units

In acute stroke management, time is brain, as narrow therapeutic windows for both intravenous thrombolysis and mechanical thrombectomy depend on expedient and specialized treatment. In rural settings, patients are often far from specialized treatment centers. Concurrently, financial constraints, cutting of services and understaffing of specialists for many rural hospitals have resulted in many patients being underserved. Mobile Stroke Units (MSU) provide a valuable prehospital resource to rural and remote settings where patients may not have easy access to in-hospital stroke care. In addition to standard ambulance equipment, the MSU is equipped with the necessary tools for diagnosis and treatment of acute stroke or similar emergencies at the emergency site. The MSU strategy has proven to be effective at facilitating time-saving stroke triage decisions. The additional on-board imaging helps to determine whether a patient should be taken to a primary stroke center (PSC) for standard treatment or to a comprehensive stroke center (CSC) for advanced stroke treatment (such as intra-arterial therapy) instead. Diagnosis at the emergency site may prevent additional in-hospital delays in workup, handover and secondary (inter-hospital) transport. MSUs may be adapted to local needs-especially in rural and remote settings-with adjustments in staffing, ambulance configuration, and transport models. Further, with advanced imaging and further diagnostic capabilities, MSUs provide a valuable platform for telemedicine (teleradiology and telestroke) in these underserved areas. As MSU programmes continue to be implemented across the world, optimal and adaptable configurations could be explored.