Dispatch of Mobile Stroke Unit Services: Results of an International Survey

Background: Treatment on Mobile Stroke Units (MSU) improves outcome for patients with acute ischemic stroke, however MSU effectiveness relies on accuracy of field dispatch. We aimed at collecting representative data on dispatch infrastructure, methods of stroke identification at the dispatcher level, operation rules and accuracy of dispatcher impression relevant to MSU operations worldwide. Methods: A survey of the PREhospital Stroke Treatment Organization (PRESTO) was conducted in 2020 to include all operational MSU clinical services worldwide. Twenty of 23 MSU services (87%) on four continents responded and participated. We assessed modes of dispatch, level of dispatcher training, numbers of and reasons for dispatches, frequency of MSU cancellation before arrival at scene and diagnoses of patients with MSU management. Results: All 20 participating MSUs reported dispatching from EMS dispatch centers. Fourteen sites also reported responding to alerts from EMS following patient evaluation. With the exception of 2 MSUs, all reported initial dispatcher training for stroke recognition, but only 6 (30%) performed regular training. Median number of dispatches per year was 325 ranging from 119 to 2174. In addition to dispatches for suspected stroke, 8 (40%) were dispatched to cardiac arrest and 13 (65%) for altered level of consciousness runs. One MSU responded to other dispatch call types including seizure, syncope, headache, sick person, and other, if the call information yielded a suspicion of possible stroke diagnosis. A median of 41% of deployments were cancelled en route. Stroke was excluded in 48% of patients assessed on scene. Eighteen percent of assessed patients were diagnosed with cerebral ischemia within 4.5 hours. Conclusions: Allocating specialized resources such as MSUs to the most clinically appropriate calls is key to their efficacy and their ability to result in improved patient outcomes. Improving dispatcher recognition of stroke can potentially be ameliorated by local team education and routine feedback.