Abstract TP247: A Comparison of Time to Treatment Between an Emergency Department-Focused Stroke Protocol and Mobile Stroke Units

Abstract

Background: San Francisco is a relatively compact city with a population of 884,000 and nine stroke centers within a 47 square mile area. Emergency medical services (EMS) transport distances and times are short and there are currently no mobile stroke units (MSUs). Methods: We evaluated EMS activation to CT (EMS-CT) and EMS activation to thrombolysis (EMS-TPA) times for acute stroke in the first two years after implementation of an emergency department (ED)-focused, direct EMS-to-CT protocol entitled “Mission Protocol” (MP) at a safety net hospital in San Francisco and compared our performance to published reports from MSUs. EMS times were abstracted from ambulance records. Geometric means were calculated for MP data and pooled means were similarly calculated from published MSU data. Results: From July 2017 through June 2019, a total of 423 patients with suspected stroke were evaluated under the MP, and 166 of these patients were ultimately diagnosed with ischemic stroke. EMS and treatment time data were available for 129 of these patients with 60 patients (47%) receiving IV-tPA with mean EMS-CT and EMS-TPA times of 41 minutes (95% CI 39-43) and 64 minutes (95% CI 58-70), respectively. The pooled estimates for MSUs suggested a mean EMS-CT time of 35 minutes (95% CI 27-45) and a mean EMS-TPA time of 48 minutes (95% CI 39-60). MSUs achieved faster EMS-CT and EMS-TPA times (p<0.0001 for both). Conclusions: In moderate-sized, urban settings with high population densities, our protocol was able to achieve EMS activation to treatment times that were comparable but ultimately slightly slower than published performance data from MSUs.