Cerebrospinal fluid pulse pressure method: a possible substitute for the examination of B waves.
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.
Lenfeldt
Niklas
N
Department of Clinical Neuroscience, Umeå University Hospital, University of Umeå, Sweden. niklas.lenfeldt@neuro.umu.se
Andersson
Nina
N
Agren-Wilsson
Aina
A
Bergenheim
A Tommy
AT
Koskinen
Lars-Owe D
LO
Eklund
Anders
A
Malm
Jan
J
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*