Impact of Expanding the Prehospital Stroke Bypass Time Window in a Large Geographic Region

Background and Purpose—The Ontario Acute Stroke Medical Redirect Paramedic Protocol (ASMRPP) was revised to allow paramedics to bypass to designated stroke centers if total transport time would be <2 hours and total time from symptom onset <3.5 hours. We sought to evaluate the impact and safety of implementing the Revised ASMRPP. Methods—We conducted a 12-month implementation study involving prehospital patients presenting with possible stroke symptoms. A total of 1317 basic and advanced life support paramedics, of 9 land services in 10 rural counties and 5 cities, used the Revised ASMRPP to take appropriate patients directly to 6 designated stroke centers. Results—We enrolled 1277 patients with 98.8% paramedic compliance in form completion. Of these, 755 (61.2%) met the redirect criteria and had these characteristics: mean age 72.1 (range 16–101), male 51.1%, mean time scene to hospital 16.7 minutes (range 0–92). Paramedics demonstrated excellent interobserver agreement (κ, 0.94; 95% confidence interval,...