EMF1 A GIS Evaluation of a Statewide EMS Stroke Routing Protocol on Community Hospital Bypass for Acute Stroke Patients

Abstract

Background: On January 1st, 2010, the North Carolina (NC) Office of Emergency Medical Services (EMS) implemented an out-of-Stroke Triage and Destination Plan (STDP) for patients with suspected acute stroke. The STDP requires that EMS providers categorize destination hospitals as being a community hospital (CH), a Stroke Capable Hospital (SCH) or a Joint Commission Certified Primary Stroke Centers (JCCPSC). The STDP specifies that, within certain constraints, hospitals unable to routinely provide IV tissue plasminogen activator (CH) should be bypassed for patient transport to hospitals with that capability (SCH or JCCPSC). Study Objective: To determine if the STDP increased the frequency of CH bypass by EMS when transporting patients with an out-of-hosptial impression of acute stroke with the following time constraints: ability to be transported to a SCH or a JCCPSC within 2 hours from symptom onset, and with a transport time not exceeding 50 minutes. Methods: Utilizing a before-after design, geographical information system (GIS) analytical methods, and a statewide Prehospital Medical Information System database, we identified patients with a suspected acute stroke who accessed EMS within 120 minutes of symptom onset. We compared two time periods: the 12 months immediately before implementation of the STDP and the 12-month period beginning 3 months after STDP implementation. We geocoded incident and hospital addresses using Esri ArcGIS software and other available source data, including address points and/or NC Department of Transportation (DOT) Integrated Statewide Road Network (ISRN). We used Esri Network Analyst software and NC DOT ISRN data to determine the closest acute care hospital to stroke incident locations. We then identified cases in which EMS bypass of a community hospital within the specified time constraints was an option and determined if bypass occurred. Chi square analysis was used to compare the pre- and post-STDP periods. Results: We identified 2,624 patients with a symptom onset 120 minutes from EMS arrival, an out-of-hospital impression of acute stroke, and a geocodable scene address with a community hospital as the closest acute care hospital. Of those patients, 43% (n=1141) were in the pre-STDP period, while 57% (n=1483) were in the post STDP period. Preliminary results indicate that a community hospital was bypassed 52% of the time in the pre-STDP period and 50% of the time in the post-STDP period. At the time of abstract submission, it was not yet known how many of these cases met the specified time constraints of the STDP. Sensitivity analyses are ongoing to determine the comparability of patients in each of the study periods. Conclusion: Our preliminary results suggest that the STDP had no impact on the rate of EMS bypass of community hospitals for patients with suspected acute stroke. Final results will be presented at the 2012 ACEP Research Forum.