title: Noninvasive screening for intracranial hypertension in children with acute, severe traumatic brain injury.
abstract: OBJECTIVE
  The aim of this study was to determine the relationship between transcranial Doppler (TCD) derived pulsatility index (PI), end diastolic flow velocity (Vd), and intracranial pressure (ICP). The subjects in this study were 36 children admitted after severe traumatic brain injury (TBI) (postresuscitation Glasgow Coma Scale ≤ 8) undergoing invasive ICP monitoring.
  
  
  METHODS
  Subjects underwent a total of 148 TCD studies. TCD measurements of systolic flow velocity (Vs), Vd, and mean flow velocity (Vm) were performed on the middle cerebral artery (MCA) ipsilateral to the ICP monitor. The PI was calculated by the TCD software (Vs-Vd/Vm). ICP registrations were made in parallel with TCD measurements.
  
  
  RESULTS
  Using a PI threshold of 1.3, postinjury Day 0-1 PI had 100% sensitivity and 82% specificity at predicting an ICP ≥ 20 mm Hg (n = 8). During this time frame, a moderately strong relationship was observed between the MCA PI and actual ICP (r = 0.611, p = 0.01). When using a threshold of < 25 cm/sec, postinjury Day 0-1 Vd had a 56% sensitivity to predict an ICP ≥ 20 mm Hg. Beyond the initial 24 hours from injury, the sensitivity of an MCA PI of 1.3 to detect an ICP ≥ 20 mm Hg was 47%, and a weak relationship between actual ICP values and MCA PI (r = 0.376, p = 0.01) and MCA Vd (r = -0.284, p = 0.01) was found.
  
  
  CONCLUSIONS
  Postinjury Day 0-1 MCA PI > 1.3 has good sensitivity and specificity at predicting an ICP ≥ 20 mm Hg. In those children with TBI who initially do not meet clear criteria for invasive ICP monitoring but who are at risk for development of intracranial hypertension, TCD may be used as a noninvasive tool to screen for the development of elevated ICP in the first 24 hours following injury.
authors.affiliation: Division of Critical Care Medicine, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University, Columbus, Ohio; and.
authors.forename: Nicole F
authors.initials: NF
authors.lastname: O'Brien
authors.affiliation: Division of Critical Care Medicine, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University, Columbus, Ohio; and.
authors.forename: Tensing
authors.initials: T
authors.lastname: Maa
authors.affiliation: School of Nursing, School of Medicine, Department of Pediatrics, Duke University, Durham, North Carolina.
authors.forename: Karin
authors.initials: K
authors.lastname: Reuter-Rice
mesh_terms: D000293:Adolescent; D001783:Blood Flow Velocity; D001930:Brain Injuries / Q000150:complications* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D056424:Decompressive Craniectomy; D005260:Female; D006801:Humans; D019586:Intracranial Hypertension / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000601:surgery; D008297:Male; D020768:Middle Cerebral Artery / Q000503:physiopathology; D008991:Monitoring, Physiologic; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011673:Pulsatile Flow; D012212:Rheology / Q000379:methods*; D012680:Sensitivity and Specificity; D017585:Ultrasonography, Doppler, Transcranial
keywords: GCS = Glasgow Coma Scale; ICP = intracranial pressure; MCA = middle cerebral artery; PI = pulsatility index; TBI = traumatic brain injury; TCD = transcranial Doppler; Vd = diastolic flow velocity; Vm = mean flow velocity; Vs = systolic flow velocity; end diastolic flow velocity; intracranial hypertension; intracranial pressure; pediatrics; pulsatility index; transcranial Doppler ultrasound; trauma; traumatic brain injury