Abstract TMP70: Simulation Modeling Predicts Actual Patient Transport Rates Following the Implementation of a Prehospital Comprehensive Stroke Center Direct Transport Protocol

Abstract

Introduction: Implementing emergency medical services (EMS) protocols that incorporate severe stroke screening and direct transport to comprehensive stroke centers (CSCs) has been advocated as a strategy to improve timely stroke care for patients with large vessel occlusion and hemorrhage, but such screening can have important unintended effects on stroke systems of care. Mathematical modeling can estimate the impact of prehospital CSC direct transport protocols, but few models have been evaluated after protocol implementation. Hypothesis: The proportion of patients transported to CSCs versus primary stroke centers (PSCs) in a mathematical model will approximate actual transport rates following implementation of a prehospital CSC direct transport protocol. Methods: A previously reported discrete event data simulation was used to model the proportion of patients with suspected stroke transported directly to CSCs in a large, urban EMS system with 8 CSCs, 24 PSCs, and a single municipal fire-based EMS agency responding to all 9-1-1 calls prior to implementation of a prehospital CSC direct transport protocol in late 2018. Electronic patient care records in which paramedics documented “suspected stroke” were included for analysis. The proportion of patients transported to CSCs versus PSCs in the 3 months (92 days) prior to and following protocol implementation were compared using Fisher’s exact test in Stata 12.1 (College Station, TX). Results: The simulation predicted that the proportion of patients transported to CSCs would increase by 8.3% following implementation of a prehospital CSC direct transport protocol. In the 3 months prior to protocol implementation, 247 of 872 (28.3%) suspected stroke patients were transported to CSCs, and 265 of 701 (37.8%) were transported to CSCs in the 3 months following implementation, a difference of 9.5% (p<0.001). The model underestimated the proportion of patients transported to CSCs by 1.2%. Conclusions: A mathematical model simulating the proportion of patients transported to CSCs differed by only 1.2% compared to actual rates after implementation of a prehospital CSC direct transport protocol. Simulation modeling holds promise for estimating system-level effects prior to EMS protocol implementation.