Abstract TP87: Discrete-event Simulation Of The Prehospital Stage Of The Acute Ischemic Stroke

Abstract

Introduction: It is critical to treat Acute Ischemic Stroke (AIS) patients quickly; however, treatment eligibility is dependent on the arrival time to the nearest stroke center by Private Vehicle (PV) or Emergency Medical Services (EMS). The duration in the prehospital stage is defined as the period from stroke onset to arrival at a non-stroke center, primary stroke center or comprehensive stroke center. This study aims to detail the prehospital stage of suspected AIS patients in order to identify opportunities for process improvements. Methods: Discrete-event simulation (DES) is a powerful decision-making tool and robust methodology for evaluating treatment processes and allows for improvements to be tested before implementing changes using real resources. A DES is developed using ARENA software to model the prehospital stage of suspected AIS patients. The process steps include two treatment pathways, PV and EMS. The pathways differ because those patients arriving via EMS allow for the activation of the code stroke protocol prior to hospital arrival. The drive times from the stroke scene to the hospital were kept constant at 40 min assuming a suburban transport. The model assumes 60% recognition of ischemic stroke using EMS stroke screening tools and large vessel occlusion screening tools and a 90% probability that the paramedics correctly screen for a potential stroke and bypass to a stroke center. The primary outcome measure is median onset-to-door time, defined as the time from onset of stroke symptoms to arrival to the hospital. The Mann-Whitney U test is used for evaluating statistical significance among the outputted median onset-to-door time for all scenarios. Results: The following process improvement scenarios were run: reducing the waiting time for EMS on average from 7 min to 5 min and reducing delays on-scene on average from 20 min to 15 min, and the median onset-to-door time reductions were from a median of 57.53 min to a median of 51.41 min (p<0.0001). Conclusions: Reduction in onset to arrival times is possible by reducing waiting time for the EMS and delay on-scene of the stoke.