Abstract WP206: Characterizing Prehospital Emergency Medical Services Dispatch Diagnostics in Large Vessel Occlusion Stroke Detection

Introduction: Stroke requires early recognition and dispatch of adequate Emergency Medical Services (EMS). Traditional EMS dispatch systems are not geared toward the utilization of Mobile Stroke Treatment Units (MSTUs). We evaluated the initial dispatched complaint for patients with large vessel occlusion (LVO) strokes and evaluated if the time of MSTU dispatch impact stroke patient outcomes. Methods: We reviewed all patients with LVO ischemic strokes evaluated in the MSTU between 7/25/23 to 6/30/25. All patients who initiated their 911 calls in Alachua County were included in the study. We reviewed EMS dispatch records to determine the time of call, initial complaint, and whether the MSTU was dispatched at the time of the call (early dispatch) or at a later time (late dispatch). Stroke metrics such as time to CT and time to needle, and time to puncture were calculated from the initial 911 call. We also evaluated discharge NIHSS and modified Rankin Score (mRS). Univariate and multivariate logistic regression analyses were performed to evaluate differences between patients with early vs late MSTU dispatch. Results: In this study, 48 patients with LVO were treated on the MSTU (mean age of 72 years and 50% male); in 24 cases the MSTU was dispatched early. The most common reasons for late dispatch were unconscious/fainting (29%), fall (29%) and other (34%). Initial NIHSS was higher for late-dispatch patients. The early MSTU dispatch group arrived faster to scene (15.5 vs. 26.3 min., p<0.001) and had CT scan completed faster (29.5 vs. 36.8 min., p=0.003). Time to thrombolytics and time to groin puncture were also faster but not statistically significant (Discharge NIHSS was significantly lower in the early MSTU dispatch group (mean 2.25 vs. 8.46, p=0.045), but there were no differences in mRS when dichotomized to good (mRS 0-2) vs. poor outcomes (3-5). On logistic regression analysis adjusting for age, gender, initial NIHSS, and TNK treatment, there were no differences in discharge NIHSS (OR 0.96 (CI 0.68-1.01), p=0.014) or discharge mRS (OR 1.06 (CI 0.15-8.12), p=0.95). Conclusion: Early MSTU dispatch results in faster arrival on scene and faster CT. Late dispatch was more likely to occur for calls that did not specifically report “stroke” or in the setting of higher NIHSS, which could affect the caller and dispatch ability to assess for stroke. Further studies are warranted to optimize the accuracy of the current dispatching system.