Abstract WP290: Direct Ambulance to Imaging Based Mission Protocol Improves Thrombolysis Metrics for Prehospital Suspected Acute Stroke Patients

Abstract

Background: The Mission Protocol was implemented in 2017 to expedite stroke evaluation and reduce door-to-needle (DTN) times at Zuckerberg San Francisco General Hospital. The key system change was emergency medical service (EMS) provider transport of patients directly to CT on arrival. Methods: Patients were eligible for a Mission Protocol prehospital stroke activation if an EMS provider found a positive Cincinnati Prehospital Stroke Scale and a last known normal time within 6 hours. We performed a chart review to compare treatment metrics between the first year of Mission Protocol patients and patients from the year prior who were also brought in via ambulance with concern for stroke and a last known normal time within 6 hours. All patients who received thrombolysis as part of their initial evaluation and treatment were included. No outliers were excluded. Median Door to CT and DTN times were compared using two sample Wilcoxon rank-sum (Mann-Whitney) tests. Results: The Mission Protocol cohort had 236 patients and the comparison cohort had 112 patients with results described in the table. The Mission Protocol was associated with a 10 minute faster median door to CT time (p<0.00001), a 6 minute faster median DTN time (p=0.0046), a 22% increase in the proportion of patients treated within 45 minutes of hospital arrival (84% vs 62%), and a 12% increase in the proportion of patients treated within 60 minutes (92% vs 80%). There were 8 stroke mimics treated in the Mission Protocol cohort compared to 2 in the comparison cohort. Symptomatic intracranial hemorrhage only occurred in one Mission Protocol patient with an ischemic stroke. Conclusion: The EMS direct to CT based Mission Protocol was associated with faster median door to CT and DTN times. There was a 22% increase in the proportion of thrombolysis patients treated within 45 minutes or less. More stroke mimic patients received thrombolysis but symptomatic intracranial hemorrhage only occurred in one ischemic stroke patient.