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J Neurosurg. 2016 Dec;125(6):1493-1503. Epub 2016 Feb 26.

The correlation between pulsatile intracranial pressure and indices of intracranial pressure-volume reserve capacity: results from ventricular infusion testing.

Author information

1
Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, and Faculty of Medicine, University of Oslo, Norway.

Abstract

OBJECTIVE The objective of this study was to examine how pulsatile and static intracranial pressure (ICP) scores correlate with indices of intracranial pressure-volume reserve capacity, i.e., intracranial elastance (ICE) and intracranial compliance (ICC), as determined during ventricular infusion testing. METHODS All patients undergoing ventricular infusion testing and overnight ICP monitoring during the 6-year period from 2007 to 2012 were included in the study. Clinical data were retrieved from a quality registry, and the ventricular infusion pressure data and ICP scores were retrieved from a pressure database. The ICE and ICC (= 1/ICE) were computed during the infusion phase of the infusion test. RESULTS During the period from 2007 to 2012, 82 patients with possible treatment-dependent hydrocephalus underwent ventricular infusion testing within the department of neurosurgery. The infusion tests revealed a highly significant positive correlation between ICE and the pulsatile ICP scores mean wave amplitude (MWA) and rise-time coefficient (RTC), and the static ICP score mean ICP. The ICE was negatively associated with linear measures of ventricular size. The overnight ICP recordings revealed significantly increased MWA (> 4 mm Hg) and RTC (> 20 mm Hg/sec) values in patients with impaired ICC (< 0.5 ml/mm Hg). CONCLUSIONS In this study cohort, there was a significant positive correlation between pulsatile ICP and ICE measured during ventricular infusion testing. In patients with impaired ICC during infusion testing (ICC < 0.5 ml/mm Hg), overnight ICP recordings showed increased pulsatile ICP (MWA > 4 mm Hg, RTC > 20 mm Hg/sec), but not increased mean ICP (< 10-15 mm Hg). The present data support the assumption that pulsatile ICP (MWA and RTC) may serve as substitute markers of pressure-volume reserve capacity, i.e., ICE and ICC.

KEYWORDS:

CI = confidence interval; EVD = external ventricular drain; ICC = intracranial compliance; ICE = intracranial elastance; ICP = intracranial pressure; MWA = mean wave amplitude; Po = opening pressure; Pp = plateau pressure; RT = rise time; RTC = RT coefficient; Rout = resistance to CSF outflow; dP = change in pressure; dV = change in volume; hydrocephalus; intracranial compliance; intracranial elastance; intracranial pressure; mean wave amplitude; single pressure wave

PMID:
26918478
DOI:
10.3171/2015.11.JNS151529
[Indexed for MEDLINE]

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