Comparison of Time to Tissue Plasminogen Activator in Patients Receiving In-Hospital Vs. Emergency Medical Services Lab Draws

Purpose: Tissue plasminogen activator (tPA) is beneficial when given within 4.5 hours of acute ischemic stroke onset, giving patients an increased likelihood to recover without any significant disability within a 3-month time period. Delays in diagnosis and laboratory data can place patients outside the tPA window. In an attempt to shorten time to tPA administration, some emergency medical services (EMS) companies have begun drawing blood for labs in the ambulance. The aim of this study is to determine if laboratory draws inside the ambulance shorten the time to tPA administration. Methods: This study is a retrospective chart review of patients admitted to a 348-bed community hospital for acute ischemic stroke who received tPA. Patients were included if they were greater than 18 years of age who have arrived at the hospital via EMS who have had an ischemic stroke with a clearly defined time of onset, a deficit measurable on the NIHSS, and a baseline computed tomographic (CT) scan of the brain that showed no evidence intracranial hemorrhage. Patients were excluded if they arrived with rapidly improving symptoms signaling a TIA, if they did not have a definitive ischemic stroke diagnosis, and/or if they had the stoke on site and did not have the opportunity to have an EMS vehicle transport. The primary outcome was to determine if receiving labs in the EMS significantly reduced door to needle time compared to receiving labs in the Emergency Department (ED). The secondary outcome was to determine if there were better health outcomes, as determined by discharge NIH scores, in patients receiving tPA within a shorter amount of time due to getting labs in an ambulance. Safety outcomes were adverse events related to tPA, such as angioedema, intracranial hemorrhage and anaphylaxis within 24 hours. Descriptive statistics were utilized. Results: Twenty-nine patients met inclusion criteria with one patient making two visits in the past year. The mean age and door to needle time (DTN) were 58.8 years-old and 77.5 minutes respectively. Hypertension, diabetes and smoking history were present in 78.1 percent, 43.7 percent, and 30 percent of patients, respectively. Of those who came by ambulance only 30 percent (n=11) had labs drawn in route to the hospital. The average DTN for those who had labs drawn in the EMS was 77.7 minutes. From the remaining patients, the average DTN time from the who had labs drawn at the hospital was 86.3 minutes. During the study, two patients expired from complications of tPA. One patient suffered a repeat stroke within the year. Conclusions: EMS lab draw in patients suspected of acute ischemic stroke was associated with a 8.6-minute decrease in door to needle time compared to patients who had labs drawn at the hospital. Clinical significance is likely negligible.