title: Design and validation of a prehospital stroke scale to predict large arterial occlusion: the rapid arterial occlusion evaluation scale.
abstract: OBJECTIVE
  We aimed to develop and validate a simple prehospital stroke scale to predict the presence of large vessel occlusion (LVO) in patients with acute stroke.
  
  
  METHODS
  The Rapid Arterial oCclusion Evaluation (RACE) scale was designed based on the National Institutes of Health Stroke Scale (NIHSS) items with a higher predictive value of LVO on a retrospective cohort of 654 patients with acute ischemic stroke: facial palsy (scored 0-2), arm motor function (0-2), leg motor function (0-2), gaze (0-1), and aphasia or agnosia (0-2). Thereafter, the RACE scale was validated prospectively in the field by trained medical emergency technicians in 357 consecutive patients transferred by Emergency Medical Services to our Comprehensive Stroke Center. Neurologists evaluated stroke severity at admission and LVO was diagnosed by transcranial duplex, computed tomography, or MR angiography. Receiver operating curve, sensitivity, specificity, and global accuracy of the RACE scale were analyzed to evaluate its predictive value for LVO.
  
  
  RESULTS
  In the prospective cohort, the RACE scale showed a strong correlation with NIHSS (r=0.76; P<0.001). LVO was detected in 76 of 357 patients (21%). Receiver operating curves showed a similar capacity to predict LVO of the RACE scale compared with the NIHSS (area under the curve 0.82 and 0.85, respectively). A RACE scale≥5 had sensitivity 0.85, specificity 0.68, positive predictive value 0.42, and negative predictive value 0.94 for detecting LVO.
  
  
  CONCLUSIONS
  The RACE scale is a simple tool that can accurately assess stroke severity and identify patients with acute stroke with large artery occlusion at prehospital setting by medical emergency technicians.
authors.affiliation: From the Stroke Unit, Neuroscience Department, Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona (UAB), Badalona, Barcelona, Spain (N.P.d.l.O., D.C., M.M., M.G., L.D., E.L.-C., M.H.-P., A.D.); Sistema d'Emergències Mèdiques (SEM) de Catalunya, Spain (M.G., M.Q., X.E., X.J.); and Grup Ambulàncies La Pau, Badalona, Barcelona, Spain (V.C.).
authors.forename: Natalia
authors.initials: N
authors.lastname: Pérez de la Ossa
authors.forename: David
authors.initials: D
authors.lastname: Carrera
authors.forename: Montse
authors.initials: M
authors.lastname: Gorchs
authors.forename: Marisol
authors.initials: M
authors.lastname: Querol
authors.forename: Mònica
authors.initials: M
authors.lastname: Millán
authors.forename: Meritxell
authors.initials: M
authors.lastname: Gomis
authors.forename: Laura
authors.initials: L
authors.lastname: Dorado
authors.forename: Elena
authors.initials: E
authors.lastname: López-Cancio
authors.forename: María
authors.initials: M
authors.lastname: Hernández-Pérez
authors.forename: Vicente
authors.initials: V
authors.lastname: Chicharro
authors.forename: Xavier
authors.initials: X
authors.lastname: Escalada
authors.forename: Xavier
authors.initials: X
authors.lastname: Jiménez
authors.forename: Antoni
authors.initials: A
authors.lastname: Dávalos
mesh_terms: D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D002545:Brain Ischemia / Q000175:diagnosis; D015331:Cohort Studies; D003627:Data Interpretation, Statistical; D004632:Emergency Medical Services / Q000379:methods*; D004634:Emergency Medical Technicians; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis; D009460:Neurologic Examination; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D020521:Stroke / Q000175:diagnosis*
keywords: cerebrovascular occlusion; prehospital emergency care; scales; stroke, acute