Emergency Medical Services
Background: Until just a year ago, the only acute therapeutic intervention for acute ischemic stroke was IV tPA, with less than 50% of eligible patients receiving the drug, for a total of 3-5% of all patients with AIS in the United States. Almost 20 years after the approval of tPA, the DAWN trial results were established the therapeutic window for mechanical thrombectomy for large vessel occlusion (LVO) out to 24 hours, providing a therapeutic option for many more patients, including those with wake up strokes, a population previously excluded from any intervention. This adds decision making complexity for prehospital personnel, in terms of the decision of where to transport.Our county EMS system implemented the Los Angeles Motor Scale (LAMS) a validated 3-item prehospital stroke scoring tool comprised of: facial droop (absent/present), arm drift (absent/drifts down/falls rapidly), and grip strength (normal/weak grip/no grip).The objective of this study was to assess whether a prehospital Los Angeles motor scale (LAMS) predicts intervention for acute stroke.
Methods: Data from all stroke transports to a comprehensive stroke center from January 1, 2018 to October 31, 2018 were abstracted from our IRB approved prehospital research registry. Data abstracted included demographics such as age and gender, prehospital variables such as blood pressure, LAMS and Rankin scores, and outcomes including whether the patient received advanced neuroimaging, intravenous tissue plasminogen activator (tPA) or mechanical thrombectomy (MT) at the receiving facility. Statistical analyses were performed in JMP 14.0 for the Mac.
Results: The cohort (n=761) was 51% female. The median age was 72, with an interquartile range (IQR) 61-81 years. Eight percent of patients received MT. A higher LAMS was significantly associated with having MT (P2 6.6%). Twenty one percent had advanced imaging (CT perfusion). A higher LAMS was significantly associated with having CTP (P2 2%). Sixteen percent received tPA. A higher LAMS was significantly associated with having tPA (P2 4%). These associations all retained statistical significance when controlled for age, gender, mean arterial pressure, type of stroke (hemorrhagic, ischemic, transient ischemic attack, and other).
Conclusion: The LAMS is a powerful prehospital predictor of intervention for acute stroke.