title: Cerebrovascular response in infants and young children following severe traumatic brain injury: a preliminary report.
abstract: To further describe the pathophysiologic processes that occur in infants and young children after severe traumatic brain injury (TBI), we retrospectively reviewed the cerebral blood flow (CBF) values and 6-month Glasgow Outcome Scores (GOS) in 30 children < or = 8 years old (25 were < or = 4 years old) with a Glasgow Coma Score (GCS) on admission of < or = 8. Twelve females and 18 males (mean age 2.1 years, range 1 month to 8 years) underwent 61 CBF studies using stable xenon computed tomography at variable times from admission to 9 days after TBI. In 12 patients, PaCO2 was manipulated an average of 8.4 torr (range 5-11 torr) and a second CBF study performed to determine CO2 vasoreactivity (CO2VR), defined as the percent change in CBF per torr change in PaCO2. CBF on admission (n = 13)was 25.1+/-7.7 ml/100 g/min (mean +/- SEM) and was < or = 20 ml/100 g/min in 10 of 13 patients (77%). By 24 h and for up to 6 days after TBI, the mean CBF increased to 55.3+/-3.4 ml/100 g/min (range 2-95) which differed significantly from the admission CBF value (p < 0.05); a CBF of >70 ml/100 g/min tended to be associated with a good outcome. Poor outcome (GOS < or = 3) was seen uniformly in children under the age of 1 year and in patients with a CBF of < or = 20 ml/100 g/min any time after TBI. Poor outcome was seen in 85% of children under the age of 24 months, but in only 41% of children > or = 24 months old. Mean CO2VR was 2.1+/-0.6%/torr PaCO2 and ranged from 0.02 to 5.98%. Mean CO2VR tended to differ between good and poor outcome children (3.2+/-0.9 and 1.17+/-0.2%, respectively) and a CO2VR of < or = 2% was significantly associated with a poor outcome. Younger age, low CBF in the early period after TBI, and a CO2VR of <2% was associated with a poor outcome in this subgroup of children. Young children (<24 months) may represent a particular high-risk group with early hypoperfusion after severe TBI. This finding may be a key factor in the pathophysiology and outcome in this age group, and may need to be addressed in our future therapeutic protocols.
authors.affiliation: Department of Pediatric Neurosurgery, Children's Hospital of Pittsburgh, University of Pittsburgh, PA 15213-2583, USA. david-adelson@POPLAR.chp.edu
authors.forename: P D
authors.initials: PD
authors.lastname: Adelson
authors.forename: B
authors.initials: B
authors.lastname: Clyde
authors.forename: P M
authors.initials: PM
authors.lastname: Kochanek
authors.forename: S R
authors.initials: SR
authors.lastname: Wisniewski
authors.forename: D W
authors.initials: DW
authors.lastname: Marion
authors.forename: H
authors.initials: H
authors.lastname: Yonas
mesh_terms: D000367:Age Factors; D001930:Brain Injuries / Q000503:physiopathology*; D002245:Carbon Dioxide / Q000032:analysis; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D007223:Infant; D008297:Male; D010313:Partial Pressure; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014978:Xenon
chemical_list: D002245:Carbon Dioxide; D014978:Xenon