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FAST-ED scale for prehospital triage of large vessel occlusion: results in the field.

BACKGROUND
 Acute ischemic stroke (AIS) is an extremely time-sensitive condition. The field triage of stroke patients should consider a careful balance between the best destination for the timely delivery of intravenous and/or endovascular reperfusion therapies. The Field Assessment Stroke Triage for Emergency Destination (FAST-ED) scale has been shown to have an accuracy comparable to that of the National Institutes of Health Stroke Scale (NIHSS). However, it has not been tested in the field.


OBJECTIVE
 To evaluate the accuracy of the FAST-ED scale in the detection of AIS due to large vessel occlusion (LVO) in the prehospital setting.


METHODS
 A cross-sectional study of consecutive prospective data collected from February 2017 to May 2019 in the city of Porto Alegre, state of Rio Grande do Sul, Southern Brazil, correlating the prehospital FAST-ED scale scores with the hospital diagnosis of LVO. Area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.


RESULTS
 In total, 74 patients were included in the analysis. As compared with the diagnosis of LVO upon hospital discharge, the prehospital FAST-ED scale applied by paramedics had a sensitivity of 80%, a specificity of 47.7%, a PPV of 51.1%, an NPV of 77.8%, and an AUC of 0.68 (95% confidence interval [95%CI]: 0.55-0.80). Among the patients with a final diagnosis of AIS, the accuracy was higher, with an AUC of 0.75 (95%CI: 0.60-0.89), a sensitivity of 80%, a specificity of 60%, a PPV of 80%, and an NPV of 60%.


CONCLUSIONS
 In the present study, the FAST-ED scale, which was applied by paramedics in the field, demonstrated moderate accuracy but high sensitivity and NPV, which are essential attributes for a triage scale. While larger studies are still needed, these findings further support the use of the FAST-ED in stroke triage.