PHILADELPHIA – Emergency personnel miss stroke in 41% of patients in their prehospital care, a study shows. In light of this, physicians should have a high degree of suspicion for stroke when treating patients presenting with elevated systolic blood pressure, a dispatch call of stroke, prior stroke or diabetes history, and unconsciousness.
Prehospital identification and notification of stroke have been associated with both shorter door-to-needle times and increased thrombolysis rates, but "the sensitivity and specificity of prehospital care providers [are] widely variable," Dr. Ethan Brandler, of the emergency medicine department at SUNY Downstate Medical Center in Brooklyn, N.Y., told a Platform Blitz audience at the annual meeting of the American Academy of Neurology.
Dr. Ethan Brandler
To assess the rates of proper stroke diagnosis by emergency medical services (EMS), Dr. Brandler and his associates reviewed 10,384 electronic prehospital care reports of all patients delivered by EMS to a single major metropolitan site between Jan. 1, 2010, and Dec. 31, 2011.
Using the American Heart Association’s Get With the Guidelines stroke database, the investigators determined that of the 75 confirmed cases of stroke, half of which were in men aged 19-49 years, EMS personnel accurately diagnosed 44 patients.
"Forty-one percent of all stroke patients were missed by EMS," Dr. Brandler said. "And 51 patients were misdiagnosed as stroke when they had something else: stroke-mimic, sepsis, infection, [and] hypoglycemia, among other neurologic and systemic problems."
The sensitivity level of 59% and specificity level of 99.5% (95% confidence interval, 47-69 and 99.1-99.6, respectively), combined with the positive likelihood ratio of 119 (95% CI, 85-165) and the negative likelihood ratio of 0.41 (95% CI, 0.32-0.54), meant that "if a paramedic called us to say a stroke was going on, the likelihood was extremely high it was a true stroke," Dr. Brandler said. "However, when they didn’t think it was a stroke, it didn’t mean much."
Stroke risk increased 83% with each increase in prehospital systolic blood pressure quartile (P = .04), Dr. Brandler and his colleagues found.
Independent predictors of stroke being the official diagnosis included an emergency services dispatcher who reported the call as a stroke, even if EMS personnel did not ultimately diagnose it that way (age-adjusted odds ratio, 9.8; 95% CI, 2.2-43.7; P = .003]. "Perhaps [the dispatcher’s] information is better than the crew’s because it is gathered in a more systematic fashion," Dr. Brandler said.
Other independent risk factors included a history of diabetes (AAOR, 2.2; 95% CI, 1.1-4.6; P = .026) and a history of stroke (AAOR, 4.4; 95% CI, 1.3-15; P = .017).
Patients who arrived unconscious with unknown cause also were considered at higher risk for having had a stroke (AAOR, 4.4; 95% CI, 1.3-15; P = .017). This was particularly the case when patients presented with basilar artery inclusions, Dr. Brandler said.
The study was funded by grants from the National Institutes of Health. Dr. Brandler did not report any other relevant disclosures.
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