Abstract 86: Accuracy of Emergency Medical Services Dispatcher and Provider Recognition of Stroke in Clinical Practice

Abstract

Objective: It is imperative that prehospital providers accurately recognize stroke. We assessed the sensitivity of stroke recognition by emergency medical services (EMS) in clinical practice in a major US city, and assessed variables associated with failure to recognize stroke. Methods: Data from the Philadelphia EMS system was linked with data from a single comprehensive stroke center to identify patients diagnosed with transient ischemic attack, ischemic stroke, or intracerebral hemorrhage by EMS dispatchers, EMS providers, or at hospital discharge between September 2009 and October 2012. Sensitivity and positive predictive value (PPV) were calculated. Multivariable logistic regression was used to identify variables associated with EMS recognition of stroke. Results: There were a total of 709 cases, 400 of which were cerebrovascular events (38% infarct, 10% ICH, and 8% TIA). Of these cases, 80 (20%) were not recognized by EMS dispatcher or EMS provider, 90 (23%) were recognized by dispatcher alone, 87 (22%) by EMS provider alone, and 143 (36%) by both. EMS providers recognized stroke with a sensitivity of 58%, PPV 69%. Dispatchers or EMS providers recognized stroke with a sensitivity of 80%, PPV 51%. In a multivariable model, EMS providers were more likely to miss a stroke when NIHSS was low (compared to NIHSS 10+, NIHSS 5-9 OR=1.6, 95% CI 0.9-3.0 & NIHSS<5 OR=4.6, 95% CI 2.7-7.9), when motor signs were absent (OR=2.4, 95% CI 1.5-3.9), and when symptom duration was > 270 minutes (OR=2.4, 95% CI 1.5-3.8). Medics correctly recognized 81% of stroke patients with NIHSS>4 and symptom duration <270 minutes, and dispatcher or EMS providers correctly recognized 90% of these patients. Conclusions: EMS recognized stroke with limited sensitivity, resulting in a high proportion of missed stroke cases. When added to the EMS provider impression, dispatcher impression meaningfully improves the sensitivity for recognizing stroke. Maximizing sensitivity is critical to prehospital interventions which may improve overall stroke care, such as transportation to designated stroke centers or EMS prenotification of receiving hospitals.