Impact of Expanding the Prehospital Stroke Bypass Time Window in a Large Geographic Region Journal Articles uri icon

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  • 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, 0.91–0.96) and 97.9% accuracy in interpretation of the Revised ASMRPP. Prehospital adverse events occurred in 14.7% of patients, but few were life-threatening. Overall, 71.4% of 755 cases had a stroke code activated at the hospital and 23.2% received thrombolysis. For the 189 potential stroke patients picked up in 1 city, the ASMRPP classified thrombolysis administration with sensitivity 100% and specificity 37.3% and a final diagnosis of stroke, with sensitivity 86.1% and specificity 41.9%. Conclusions— In a large urban–rural area with 9 paramedic services, we demonstrated accurate, safe, and effective implementation of the Revised ASMRPP. These revisions will allow more patients with stroke to benefit from early treatment.


  • Stiell, Ian G
  • Clement, Catherine M
  • Campbell, Kristy
  • Sharma, Mukul
  • Socha, Doug
  • Sivilotti, Marco LA
  • Jin, Albert
  • Perry, Jeffrey J
  • Lumsden, Jim
  • Martin, Cally
  • Froats, Mark
  • Dionne, Richard
  • Trickett, John

publication date

  • March 2017

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