Decision for tPA Administration, Not Response Time, Contributes Most to Variation in Thrombolysis Times Onboard Mobile Stroke Unit

Abstract

Background Hospitals have improved stroke thrombolysis times through rigorous assessment of care delays. However, this same rigor has not yet been applied to the novel setting of mobile stroke units (MSUs). Methods We reviewed all cases of intravenous tPA (tissue‐type plasminogen activator) administration onboard our MSU in Rochester, NY, since its first complete year of operation in 2019. The dispatch timeline was divided into 6 intervals: (1) response time, (2) onboarding time, (3) head computed tomography collection, (4) head computed tomography reading, (5) decision time, and (6) intravenous tPA administration. Results The mean±SD total time between MSU dispatch and tPA was 42±8.4 minutes (range, 26–60 minutes; N=53). The largest mean duration was in (1), between dispatch and arrival (12.0±4.7 minutes). However, the intercase variation was greatest in (5), between head computed tomography reading and treatment decision (6.3±6.2 minutes). After ranking cases by total time, the mean decision times of first and fourth quartile cases varied the most, by a factor of 2.45, whereas the mean times for the other intervals varied by <1.50. Decision time was the interval most closely correlated with the mean total time (Spearman ρ=0.46; P =0.00051), which significantly decreased from 2019 to 2020 (Mann‐Whitney, Z=2.38; P =0.02). Decision time was negatively correlated with time since inception of the MSU (Spearman ρ=−0.29; P =0.037; Figure 2B), suggesting that decision time drove both variations and improvements in overall thrombolysis time. Conclusions The primary driver of variation in total time from emergency alert to tPA administration is provider decision time in our MSU program in Rochester, NY. This observation should be investigated in other settings but may ultimately inform MSU training and staffing to optimize MSU treatment timelines.