Investigation of the relationship between transcranial impedance and intracranial pressure

M. Shaw, I. Piper, P. Campbell, C. McKeown, J. Britton, K. Oommen, L. Stewart, I. Whittle, Rachael Gregson, E. Clutton

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Studies on piglets have shown that cranial bioimpedance (Z) measurements correlate well with invasively measured intracranial pressure (ICP). We have tested the feasibility of collecting transcranial impedance from a clinical device for measuring whole-body water content (ImpediMed SFB7). In the clinical study, 50 normal healthy volunteers had transcranial impedance measured using nine different head montages (forehead to mastoid (left/right), temporal to mastoid (left/right), forehead to temporal (left/right), forehead to occipital (left/right) and temporal to temporal). Impedance was measured 20 times over a frequency range per montage and ANOVA used to test for effects of electrode position upon recorded value. For the experimental study, five sedated and ventilated Marino sheep were instrumented for intraventricular ICP and transcranial impedance measurement. Measures of ICP were recorded while ICP was increased from baseline to greater than 50 mmHg in five steps using an intraventricular infusion of mock CSF. There is a significant effect of electrode position and gender upon transcranial impedance (p <0.001). The temporal-mastoid electrode position had significantly lower impedance values in keeping with its shorter path length. ICP correlated with craniospinal compliance measurements and Impedance vs Freq by ICP step shows a clear ICP dependence (p = 0.007) across the sheep.
Original languageEnglish
Title of host publicationIntracranial Pressure and Brain Monitoring XIV
PublisherSpringer Vienna
Pages61-65
Number of pages5
Volume114
ISBN (Electronic)978-3-7091-0956-4
ISBN (Print)978-3-7091-0955-7
DOIs
Publication statusPublished - 2012

Publication series

NameActa Neurochirurgica Supplementum
Volume114
ISSN (Print)0065-1419

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