Abstract Body: Background: Emergency medical services (EMS) routing of stroke patients is challenging in rural settings. To address this, the American Stroke Association (ASA) has developed a template severity-based EMS triage algorithm to direct EMS to either the nearest stroke-ready versus the nearest Comprehensive Stroke Center (CSC) hospital, but its real-world impact is uncertain.
Methods: This is an interim analysis of a before-and-after quality improvement study examining the impact of implementation of a severity-based EMS stroke destination protocol by three medical control authorities (MCAs) covering 4 rural counties in western Michigan. We defined optimal destination according to the ASA algorithm, which recommends bypass for patients within 24 of last known well if large vessel occlusion suspected and bypass will not delay thrombolysis. Chi square tests were used to compare optimal destination selection before and after implementation among EMS suspected stroke cases originating from the target counties. We also compared the time from EMS scene arrival to ischemic stroke (IS) treatment (thrombolysis or endovascular therapy [EVT]) before and after implementation using Wilcoxon Rank Sum tests.
Results: From November 2021 to May 2024, EMS transported 616 suspected stroke cases, 272 (44.2%) of which ultimately received a diagnosis of ischemic stroke (IS) or transient ischemic attack. The protocol was implemented by each MCA in random order at months 21, 23, and 29, resulting in 73 MCA-months before and 17 after implementation, excluding a one-month washout for each MCA. Optimal hospital destinations were selected for 310/499 (62.1%) patients prior to the protocol and 86/117 (73.5%) after (p=0.021). Thrombolytics were administered to 57 patients (48 before and 9 after) and 46 (42 before and 4 after) received EVT. Median times from first EMS contact to needle decreased from 98 (interquartile range [IQR]: 79-107) to 77 (IQR: 75-85) minutes (p=0.012); median times from EMS contact to groin puncture increased nonsignificantly from 165 (IQR: 132-216) to 196 (IQR: 191-228) minutes (p=0.110).
Conclusions: Interim analysis of implementation of a rural EMS severity-based triage algorithm for suspected stroke cases resulted in improved destination selection and faster thrombolysis but did not improve EVT treatment times. This analysis will be repeated once follow-up is completed in 7 months.