title: Cerebrospinal fluid pulse pressure method: a possible substitute for the examination of B waves.
abstract: OBJECTIVE
  The appearance of numerous B waves during intracranial pressure (ICP) registration in patients with idiopathic adult hydrocephalus syndrome (IAHS) is considered to predict good outcome after shunt surgery. The aim of this study was to describe which physical parameters of the cerebrospinal fluid (CSF) system B-waves reflect and to find a method that could replace long-term B-wave analysis.
  
  
  METHODS
  Ten patients with IAHS were subjected to long-term registration of ICP and a lumbar constant-pressure infusion test. The B-wave presence, CSF outflow resistance (R(out)), and relative pulse pressure coefficient (RPPC) were assessed using computerized analysis. The RPPC was introduced as a parameter reflecting the joint effect of elastance and pulsatory volume changes on ICP and was determined by relating ICP pulse amplitudes to mean ICP.
  
  
  CONCLUSIONS
  The B-wave presence on ICP registration correlates strongly with RPPC (r = 0.91, p < 0.001, 10 patients) but not with CSF R(out). This correlation indicates that B waves-like RPPC-primarily reflect the ability of the CSF system to reallocate and store liquid rather than absorb it. The RPPC-assessing lumbar short-term CSF pulse pressure method could replace the intracranial long-term B-wave analysis.
authors.affiliation: Department of Clinical Neuroscience, Umeå University Hospital, University of Umeå, Sweden. niklas.lenfeldt@neuro.umu.se
authors.forename: Niklas
authors.initials: N
authors.lastname: Lenfeldt
authors.forename: Nina
authors.initials: N
authors.lastname: Andersson
authors.forename: Aina
authors.initials: A
authors.lastname: Agren-Wilsson
authors.forename: A Tommy
authors.initials: AT
authors.lastname: Bergenheim
authors.forename: Lars-Owe D
authors.initials: LO
authors.lastname: Koskinen
authors.forename: Anders
authors.initials: A
authors.lastname: Eklund
authors.forename: Jan
authors.initials: J
authors.lastname: Malm
mesh_terms: D000328:Adult; D001794:Blood Pressure; D002555:Cerebrospinal Fluid; D004548:Elasticity; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis* / Q000503:physiopathology*; D007427:Intracranial Pressure; D016014:Linear Models; D008954:Models, Biological; D008991:Monitoring, Physiologic / Q000379:methods*