Abstract 3291: Accuracy of Stroke Identification by EMS Dispatch Units: An Analysis of National Emergency Medical Services Information System Data (NEMSIS).
Background: The accuracy of stroke identification by dispatch units is an important determinant for directing appropriate level of Emergency Medical Services (EMS) and response times.
Objective: To determine the accuracy of stroke identification by the dispatch center as the first responder and to identify barriers to the accurate diagnosis.
Methods: We used the 2009 National Emergency Medical Services Information System (NEMSIS) Research Dataset, which is representative of 26 states in the US. We compared the diagnosis for dispatch based on ascertainment by dispatch staff with the diagnosis made by EMS after arrival at scene for identification of stroke/cerebrovascular accident (CVA) and determined the reasons for false diagnosis. We also estimated the sensitivity, specificity, and predictive values of dispatch diagnosis of stroke/CVA.
Results: Among the 58013 patients identified by the dispatch center as stroke/CVA, 35118(60.5%) were diagnosed as stroke/CVA by EMS after evaluation at scene. Among the patients with false dispatch diagnosis, the EMS diagnosis was as follows: 8401(14.5%) altered level of consciousness, 4107(7.1%), syncope/fainting, 2391(4.1%) diabetic symptoms-hypoglycemia, 917(1.6%) seizures and 7079(12.2%) other. Identification of stroke by dispatch unit showed a sensitivity of 57%, specificity of 99.03%, positive predictive value of 60.5%, negative predictive value of 98.8%, positive likelihood ratio of 59 (95% CI 58-60) and negative likelihood ratio of 0.43(95% CI 0.43-0.44).
Conclusion: The complaint of stroke/CVA reported by dispatch unit to EMS seems to have low sensitivity but high specificity. Efforts are required to increase the sensitivity of dispatch unit diagnosis of stroke to ensure appropriate level of EMS care is dispatched and reduce response times.
- © 2012 by American Heart Association, Inc.