title: Early cerebral monitoring using the transcranial Doppler pulsatility index in patients with severe brain trauma.
abstract: BACKGROUND
  The early posttraumatic period is critical in patients with traumatic brain injury (TBI) because of the increased risk of secondary ischemic injuries to the injured brain. For these patients, cerebral perfusion pressure (CPP) monitoring is recommended. This, however, requires an invasive device to measure intracranial pressure (ICP). Transcranial Doppler (TCD) ultrasonography is an effective, noninvasive method for the detection of cerebral hemodynamic changes. Use of the dimensionless TCD-pulsatility index (PI) has the advantage of eliminating errors in measurements due to insonation angle variations.
  
  
  METHODS
  We investigated 37 patients with severe TBI (GCS < or = 8 on admission). The TCD parameters included the systolic, diastolic, and mean velocities of the middle cerebral artery (MCV) and the pulsatility index (PI). Mean arterial pressure (MAP), ICP, CPP, and simultaneous arterial and venous blood gases were also measured.
  
  
  RESULTS
  We observed a strong correlation between ICP and PI (r = 0.82, p < 0.0001) for ICP values >20 mmHG. The correlation of CPP to PI were also statistically significant (P < 0.0001). The strongest inverse correlation between CPP and PI was obtained (r = 0.86, p < 0.0001) for CPP values below 70 mmHg.
  
  
  CONCLUSIONS
  Pulsatility index measurements permit the early identification of patients with low CPP and high risk of cerebral ischemia. In emergency situations it can be used alone when ICP monitoring is contraindicated or not readily available.
authors.affiliation: Neurosurgical Clinic, Medical School University of Ioannina, Ioannina, Greece.
authors.forename: Spyridon G
authors.initials: SG
authors.lastname: Voulgaris
authors.forename: Melpomeni
authors.initials: M
authors.lastname: Partheni
authors.forename: Harikleia
authors.initials: H
authors.lastname: Kaliora
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Haftouras
authors.forename: Ilias S
authors.initials: IS
authors.lastname: Pessach
authors.forename: Kostadinos S
authors.initials: KS
authors.lastname: Polyzoidis
mesh_terms: D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D002545:Brain Ischemia / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D011312:Pressure; D013997:Time Factors; D017585:Ultrasonography, Doppler, Transcranial