HONOLULU—Emergency medical services (EMS) in New York City have a positive predictive value of 64% for diagnosing stroke in an underserved minority population, with seizures being the leading confounder, according to research presented at the 2013 International Stroke Conference. Investigators observed no overall difference in positive predictive value between responding emergency medical technicians (Basic Life Support) and paramedics (Advanced Life Support) within the New York City 911 system.
Of 736 patients suspected by EMS of having a stroke, the diagnosis subsequently was confirmed for 468 patients, reported Ethan S. Brandler, MD, Clinical Assistant Professor of Emergency Medicine and Internal Medicine and Emergency Medical Services Medical Director at the State University of New York, Downstate Medical Center, Brooklyn, New York. Of the 268 persons who did not have a confirmed stroke, 76 (28%) had a seizure, 30 (11%) had syncope, 27 (10%) had an infection, and 21 (8%) had hypoglycemia.
“Our data suggest that the Fire Department of New York (FDNY) EMS called seizures a stroke more commonly than the other three leading confounding diagnoses—hypoglycemia, syncope, and infection—combined,” stated Dr. Brandler. “This was true more for Advanced Life Support than for Basic Life Support.”
Dr. Brandler’s group reviewed the medical records of all patients (85% Caribbean Blacks) who were transported by EMS to participating Brooklyn facilities between January 1, 2010, and December 31, 2011. The researchers then compared EMS impressions of the presenting problem with American Heart Association/American Stroke Association Get With the Guidelines databases that were operational in all participating facilities.
After reviewing the medical records of patients who were thought to have had a stroke by EMS but whose diagnosis was not confirmed by a Get With the Guidelines diagnosis, the investigators inquired about a confounding diagnosis. Patients who were not transported by FDNY EMS were excluded.
Basic Life Support had a confirmed stroke diagnosis rate in 66% of cases, compared with 58% for Advanced Life Support. Seizure was the leading confounder, accounting for 20.1% of misdiagnoses by Advanced Life Support, compared with a rate of 7.8% by Basic Life Support.
“Our results suggest an area of focused EMS education,” concluded Dr. Brandler. “Further study is planned to determine the accuracy of Advanced Life Support versus Basic Life Support providers for the diagnosis of stroke.”
—Colby Stong
Editor
Suggested Reading
Bray JE, Coughlan K, Barger B, Bladin C. Paramedic diagnosis of stroke: examining long-term use of the Melbourne Ambulance Stroke Screen (MASS) in the field. Stroke. 2010;41(7):1363-1366.
Frendl DM, Strauss DG, Underhill BK, Goldstein LB. Lack of impact of paramedic training and use of the Cincinnati prehospital stroke scale on stroke patient identification and on-scene time. Stroke. 2009;40(3):754-756.