title: Late night activity regarding stroke codes: LuNAR strokes.
abstract: BACKGROUND
  There is diurnal variation for cardiac arrest and sudden cardiac death. Stroke may show a similar pattern. We assessed whether strokes presenting during a particular time of day or night are more likely of vascular etiology.
  
  
  OBJECTIVE
  To compare emergency department stroke codes arriving between 22:00 and 8:00 hours (LuNAR strokes) vs. others (n-LuNAR strokes). The purpose was to determine if late night strokes are more likely to be true strokes or warrant acute tissue plasminogen activator evaluations.
  
  
  METHODS
  We reviewed prospectively collected cases in the University of California, San Diego Stroke Team database gathered over a four-year period. Stroke codes at six emergency departments were classified based on arrival time. Those arriving between 22:00 and 8:00 hours were classified as LuNAR stroke codes, the remainder were classified as 'n-LuNAR'. Patients were further classified as intracerebral hemorrhage, acute ischemic stroke not receiving tissue plasminogen activator, acute ischemic stroke receiving tissue plasminogen activator, transient ischemic attack, and nonstroke. Categorical outcomes were compared using Fisher's Exact test. Continuous outcomes were compared using Wilcoxon's Rank-sum test.
  
  
  RESULTS
  A total of 1607 patients were included in our study, of which, 299 (19%) were LuNAR code strokes. The overall median NIHSS was five, higher in the LuNAR group (n-LuNAR 5, LuNAR 7; P=0·022). There was no overall differences in patient diagnoses between LuNAR and n-LuNAR strokes (P=0·169) or diagnosis of acute ischemic stroke receiving tissue plasminogen activator (n-LuNAR 191 (14·6%), LuNAR 42 (14·0%); P=0·86). Mean arrival to computed tomography scan time was longer during LuNAR hours (n-LuNAR 54·9±76·3 min, LuNAR 62·5±87·7 min; P=0·027). There was no significant difference in 90-day mortality (n-LuNAR 15·0%, LuNAR 13·2%; P=0·45).
  
  
  CONCLUSIONS
  Our stroke center experience showed no difference in diagnosis of acute ischemic stroke between day and night stroke codes. This similarity was further supported in similar rates of tissue plasminogen activator administration. Late night strokes may warrant a more rapid stroke specialist evaluation due to the longer time elapsed from symptom onset and the longer time to computed tomography scan.
authors.affiliation: Department of Neurosciences, University of California, San Diego, CA 92103, USA. gtafreshi@ucsd.edu
authors.forename: Gilda
authors.initials: G
authors.lastname: Tafreshi
authors.forename: Rema
authors.initials: R
authors.lastname: Raman
authors.forename: Karin
authors.initials: K
authors.lastname: Ernstrom
authors.forename: Karen
authors.initials: K
authors.lastname: Rapp
authors.forename: Brett C
authors.initials: BC
authors.lastname: Meyer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000175:diagnosis; D002543:Cerebral Hemorrhage / Q000175:diagnosis; D002940:Circadian Rhythm / Q000502:physiology; D059019:Clinical Coding / Q000706:statistics & numerical data; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D002546:Ischemic Attack, Transient / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020521:Stroke / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator