Abstract TMP61: Improved Routing of Comprehensive Stroke Center Appropriate Patients via Mobile Stroke Unit Conclusive Field Diagnosis

Abstract

Background: Mobile Stroke Units (MSUs) are capable of rapid initiation of intravenous thrombolysis and have the potential to improve acute stroke patient routing by providing conclusive imaging diagnosis of LVO (arterial sequences) and intracranial hemorrhage (parenchymal/extraparenchymal sequences). However, the incremental increase in diagnostic accuracy and effect on patient disposition have not been well delineated. Methods: Consecutive transports in a regionally-deployed MSU from September 2017-August 2019) were analyzed, comparing patient routing that would have occurred under standard ambulance protocols to routing and process outcomes after CT/CTA MSU imaging. Standard ambulance regional routing policy was direct to nearest PSC if Los Angeles Motor Scale (LAMS) 0-3 and direct to nearest CSC within 30m if LAMS 4-5. Results: Among 83 MSU transports, final diagnosis was acute cerebral ischemia in 68% and intracranial hemorrhage in 10%. Among 57 acute cerebral ischemia patients, Los Angeles Motor Scale (LAMS) score was 0-3 in 65% and 4-5 in 35%. All (100%) of patients with ICA/M1 occlusions had LAMS score 4-5. However, among patients with expanded range endovascular target occlusions (M2, basilar), LAMS scores were 0-3 in 56%, and MSU imaging permitted improved routing. Among 8 intracranial hemorrhage patients (2 IPH, 5 SDH, 1 SAH), MSU imaging permitted improved direct-to-CSC routing in the 62% of patients with LAMS scores 0-3. Among all MSU admissions, 15% (13) were rerouted based solely upon in-vehicle imaging, including 7% for radiographically proven endovascularly treatable occlusion, 7% for neurosurgical/NICU intracranial hemorrhage care, and 1% for neurosurgical tumor care. Transport times for re-routed patients was median 12 minutes, compared to closest stroke center median 6 minutes. Conclusion: More than 1 in 7 MSU evaluations result in improved routing of comprehensive stroke center-appropriate patients directly to a CSC facility, including AIS patients potentially eligible for thrombectomy, intracranial hemorrhage patients, and acutely-presenting brain tumor patients. In addition to speeding start of intravenous thrombolysis, MSUs can substantially improve timely access to CSC care.