title: Cerebral autoregulation in pediatric traumatic brain injury.
abstract: OBJECTIVE
  The aims of this study were to document the incidence of impaired cerebral autoregulation in children with traumatic brain injury using transcranial Doppler ultrasonography and to examine the relationship between autoregulatory capacity and outcome in children following traumatic brain injury.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Harborview Medical Center (level I pediatric trauma center) in Washington state.
  
  
  METHODS
  Thirty-six children <15 yrs old with traumatic brain injury: Glasgow Coma Scale score <9 (n = 12, group 1), Glasgow Coma Scale score 9-12 (n = 12, group 2), and Glasgow Coma Scale score 13-15 (n = 12, group 3).
  
  
  METHODS
  Cerebral autoregulation testing was conducted during extracranial surgery. Mean middle cerebral artery flow velocities were measured using transcranial Doppler as mean arterial pressure was increased to whichever variable was greater: 20% above baseline or a set value (80 mm Hg for <9 yrs and 90 mm Hg for 9-14 yrs). Autoregulatory capacity was quantified by the Autoregulatory Index. Autoregulatory Index <0.4 was considered impaired cerebral autoregulation. Discharge outcome using the Glasgow Outcome Scale score was considered good if the Glasgow Outcome Scale score was > or =4.
  
  
  RESULTS
  Twenty-four (67%) of 36 children had an Autoregulatory Index > or =0.4. The incidence of impaired cerebral autoregulation was 42% (five of 12) in group 1, 42% (five of 12) in group 2, and 17% (two of 12) in group 3. Ten (42%) of the 24 children with intact cerebral autoregulation had a good outcome compared with only one of 12 (8%) children with impaired cerebral autoregulation (p =.04). Six of 12 (50%) children with impaired cerebral autoregulation had hyperemia compared with one of 24 (4%) children with intact cerebral autoregulation (p <.01). Hyperemia was associated with poor outcome (p =.01).
  
  
  CONCLUSIONS
  The incidence of impaired cerebral autoregulation was greatest following moderate to severe traumatic brain injury. Impaired cerebral autoregulation was associated with poor outcome. Hyperemia was associated with impaired cerebral autoregulation and poor outcome.
authors.affiliation: Department of Anesthesiology, University of Washington, Seattle, WA, USA.
authors.forename: Monica S
authors.initials: MS
authors.lastname: Vavilala
authors.forename: Lorri A
authors.initials: LA
authors.lastname: Lee
authors.forename: Krishna
authors.initials: K
authors.lastname: Boddu
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Visco
authors.forename: David W
authors.initials: DW
authors.lastname: Newell
authors.forename: Jerry J
authors.initials: JJ
authors.lastname: Zimmerman
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Lam
mesh_terms: D000293:Adolescent; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001921:Brain / Q000503:physiopathology*; D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D005260:Female; D015600:Glasgow Coma Scale; D023261:Glasgow Outcome Scale; D006706:Homeostasis; D006801:Humans; D007223:Infant; D008297:Male; D020768:Middle Cerebral Artery / Q000503:physiopathology; D017585:Ultrasonography, Doppler, Transcranial