Neal S. Parikh, MD
Dr. Mullen and colleagues performed a geographic modeling study to understand the implications of several pre-hospital triage strategies on transport times. The rationale for this and related studies is that optimizing stroke systems of care requires accounting for regional and local constraints. Because most of the U.S. population lives in urban areas, investigating urban stroke systems of care is worthwhile.
Philadelphia has only one EMS provider. So, the researchers were able to use EMS data to identify and geocode all ambulance-transported patients with possible stroke and then use a maps application programming interface (API) to estimate travel times. They also had actual travel times as reported by EMS.
They compared travel times for 3 scenarios: transport to the nearest hospital, transport to the nearest primary stroke center (PSC), and transport to the nearest comprehensive stroke center (CSC).
Their computational modeling approach underestimated actual travel times, but not substantially. Transporting patients directly to a PSC required approximately 5 additional minutes of travel time, and going directly to a CSC required approximately 8 additional minutes (IQR 3.9-13.5).
There are data now from several additional large cities, such as Cincinatti1 and New York2, to suggest that EMS transport for patients with stroke is fast. Urban areas in the United States have a high density of hospitals. This study, with other modeling studies, shows that transporting directly to a PSC and/or CSC does not substantially increase travel times in such locales. While it may not be feasible to transport all patients to a CSC, it is difficult to justify transport to a non-PSC when a PSC can be reached with only 5 minutes of additional travel. PSCs may have more efficient stroke care and be allied with CSCs to facilitate rapid transfer in cases where endovascular therapy is necessary.
Though perhaps bold, it may be reasonable to discerningly adapt local stroke systems of care to mounting modeling and observational data. If such data are not felt to be sufficiently compelling to influence policy, we could start by systematically collecting data regarding relevant aspects of pre-hospital and inter-hospital travel.
1Katz BS, Adeoye O, Sucharew H, Broderick JP, McMullan J, Khatri P, et al. Estimated impact of emergency medical serviced triage of stroke patients on comprehensive stroke centers: an urban population-based study. Stroke. 2017;48:2164-2170.
2Parikh NS, Chatterjee A, Diaz I, Pandya A, Merkler AE, Gialdini G, et al. Modeling the Impact of Interhospital Transfer Network design on stroke Outcomes in a Large City. Stroke. 2018;49:370-376.