title: Accuracy of emergency medical services-reported last known normal times in patients suspected with acute stroke.
abstract: OBJECTIVE
  The last known normal (LKN) time is a critical determinant of IV tissue-type plasminogen activator (IV tPA) eligibility; however, the accuracy of emergency medical services (EMS)-reported LKN times is unknown. We determined the congruence between neurologist-determined and EMS-reported LKN times and identified predictors of incongruent LKN times.
  
  
  METHODS
  We prospectively collected EMS-reported LKN times for patients brought into the emergency department with suspected acute stroke and calculated the absolute difference between the neurologist-determined and EMS-reported LKN times (|ΔLKN|). We determined the rate of inappropriate IV tPA use if EMS-reported times had been used in place of neurologist-determined times. Univariate and multivariable linear regression assessed for any predictors of prolonged |ΔLKN|.
  
  
  RESULTS
  Of 251 patients, mean and median |ΔLKN| were 28 and 0 minutes, respectively. |ΔLKN| was <15 minutes in 91% of the entire cohort and <15 minutes in 80% of patients with a diagnosis of stroke (n=86). Of patients who received IV tPA, none would have been incorrectly excluded from IV tPA if the EMS LKN time had been used. Conversely, of patients who did not receive IV tPA, 6% would have been incorrectly included for IV tPA consideration had the EMS time been used. In patients with wake-up stroke symptoms, EMS underestimated LKN times: mean neurologist LKN time-EMS LKN time=208 minutes. The presence of wake-up stroke symptoms (P<0.0001) and older age (P=0.019) were independent predictors of prolonged |ΔLKN|.
  
  
  CONCLUSIONS
  EMS-reported LKN times were largely congruent with neurologist-determined times. Focused EMS training regarding wake-up stroke symptoms may further improve accuracy.
authors.affiliation: From the Department of Neurology (D.C., P.P., J.-M.L., A.L.F.), Program in Occupational Therapy (L.T.C.), Department of Radiology (L.T.C., J.-M.L.), and Department of Emergency Medicine (H.P., L.H., P.P., D.K.T.), Washington University School of Medicine, MO.
authors.forename: David
authors.initials: D
authors.lastname: Curfman
authors.forename: Lisa Tabor
authors.initials: LT
authors.lastname: Connor
authors.forename: Hawnwan Philip
authors.initials: HP
authors.lastname: Moy
authors.forename: Laura
authors.initials: L
authors.lastname: Heitsch
authors.forename: Peter
authors.initials: P
authors.lastname: Panagos
authors.forename: Jin-Moo
authors.initials: JM
authors.lastname: Lee
authors.forename: David K
authors.initials: DK
authors.lastname: Tan
authors.forename: Andria L
authors.initials: AL
authors.lastname: Ford
mesh_terms: D000368:Aged; D004632:Emergency Medical Services / Q000592:standards*; D004636:Emergency Service, Hospital / Q000592:standards; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020521:Stroke / Q000175:diagnosis* / Q000188:drug therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator
keywords: Emergency Medical Services; last known normal time; stroke