Abstract Body: Background
Emergency Medical Services (EMS) can shorten the time to endovascular treatment by transporting Large Vessel Occlusion (LVO) Acute Ischemic Stroke (AIS) patients directly to thrombectomy centers. The most common prehospital strategy for identifying LVO AIS is performing an LVO screen. In 2019, our county EMS system implemented the Field Assessment Stroke Triage for Emergency Destination (FAST-ED) score as its LVO screen. Our objective was to assess the agreement of the FAST-ED score components performed by the paramedic in the field with the corresponding components of the National Institute of Health Stroke Scale (NIHSS) performed by the hospital neurologist for patients discharged with an ischemic stroke diagnosis.
Methods
From a prospectively maintained database of consecutive patients ≥ 18 years old transported to one of four hospitals by our county EMS agency with a FAST-ED score documented, we conducted a retrospective study of patients diagnosed with AIS for whom the Code Stroke protocol was activated. Corresponding component score agreement was measured using unweighted Fleiss Kappa for the dichotomized measure of facial palsy and quadratic Fleiss’ Kappa for the other ordinal measures. Since ambiguity exists regarding the inclusion of dysarthria without aphasia in the FAST-ED speech changes score, agreement for that component score was compared to dysarthria and/or aphasia.
Results
From September 2019 to March 2024, we identified 829 patients meeting our inclusion criteria. The median time interval from hospital arrival to CT performance as an index of NIHSS performance time was 10 minutes (IQR 8-15). The items with substantial agreement were arm weakness (Kappa=0.676, 95% CI 0.634-0.719) and speech changes defined as dysarthria and/or aphasia (Kappa=0.614, 95% CI 0.562-0.665). Moderate agreement was found for eye deviation (Kappa=0.595, 95% CI 0.536-0.655) and speech changes not including dysarthria (Kappa=0.482, 95% CI 0.427-0.537). There was only fair agreement for facial palsy (Kappa=0.252, 95% CI 0.185-0.319) and denial/neglect (Kappa=0.329, 95% CI 0.259-0.399)
Conclusions
EMS providers may benefit from targeted education in assessing denial/neglect and facial palsy when they are components of LVO screens. The FAST-ED score would benefit from increased clarity regarding the inclusion of isolated dysarthria as scoring positive for a speech change.