title: Transcranial color-coded duplex sonography allows to assess cerebral perfusion pressure noninvasively following severe traumatic brain injury.
abstract: OBJECTIVE
  Assess optimal equation to noninvasively estimate intracranial pressure (eICP) and cerebral perfusion pressure (eCPP) following severe traumatic brain injury (TBI) using transcranial color-coded duplex sonography (TCCDS).
  
  
  METHODS
  This is an observational clinical study in a university hospital.
  
  
  METHODS
  A total of 45 continuously sedated (BIS < 50), normoventilated (paCO(2) > 35 mmHg), and non-febrile TBI patients.
  
  
  METHODS
  eICP and eCPP based on TCCDS-derived flow velocities and arterial blood pressure values using three different equations were compared to actually measured ICP and CPP in severe TBI patients subjected to standard treatment. Optimal equation was assessed by Bland-Altman analysis.
  
  
  RESULTS
  The equations: ICP = 10:927 x PI(pulsatility index) - 1:284 and CPP = 89:646 - 8:258 PI resulted in eICP and eCPP similar to actually measured ICP and CPP with eICP 10.6 +/- 4.8 vs. ICP 10.3 +/- 2.8 and eCPP 81.1 +/- 7.9 vs. CPP 80.9 +/- 2.1 mmHg, respectively. The other two equations, eCPP = (MABP x EDV)/mFV + 14 and eCPP = mFV / (mFV - EDV)] x (MABP - RRdiast), resulted in significantly decreased eCPP values: 72.9 +/- 10.1 and 67 +/- 19.5 mmHg, respectively. Superiority of the first equation was confirmed by Bland-Altman revealing a smallest standard deviations for eCPP and eICP.
  
  
  CONCLUSIONS
  TCCDS-based equation (ICP = 10.927 x PI - 1.284) allows to screen patients at risk of increased ICP and decreased CPP. However, adequate therapeutic interventions need to be based on continuously determined ICP and CPP values.
authors.affiliation: Surgical Intensive Care, University Hospital Zuerich, Zurich, Switzerland.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Brandi
authors.forename: Markus
authors.initials: M
authors.lastname: Béchir
authors.forename: Susanne
authors.initials: S
authors.lastname: Sailer
authors.forename: Christoph
authors.initials: C
authors.lastname: Haberthür
authors.forename: Reto
authors.initials: R
authors.lastname: Stocker
authors.forename: John F
authors.initials: JF
authors.lastname: Stover
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D001921:Brain / Q000098:blood supply*; D001930:Brain Injuries / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy; D020208:Brain Injury, Chronic / Q000000981:diagnostic imaging; D003399:Craniotomy; D003422:Critical Care; D005260:Female; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging; D011379:Prognosis; D011446:Prospective Studies; D011673:Pulsatile Flow / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology*; D012680:Sensitivity and Specificity; D015996:Survival Rate; D018615:Ultrasonography, Doppler, Color / Q000706:statistics & numerical data; D017585:Ultrasonography, Doppler, Transcranial / Q000706:statistics & numerical data; D055815:Young Adult