Postural effects on intracranial pressure: modeling and clinical evaluation
2013 (English)In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 115, no 10, 1474-1480 p.Article in journal (Refereed) Published
Introduction The physiological effect of posture on intracranial pressure (ICP) is not well described. This study defined and evaluated three mathematical models describing the postural effects on ICP, designed to predict ICP at different head-up tilt-angles from the supine ICP value.
Methods Model I was based on a hydrostatic indifference point for the cerebrospinal fluid (CSF) system, i.e. the existence of a point in the system where pressure is independent of body position. Models II and III were based on Davson's equation for CSF absorption, which relates ICP to venous pressure, and postulated that gravitational effects within the venous system are transferred to the CSF system. Model II assumed a fully communicating venous system and model III that collapse of the jugular veins at higher tilt-angles creates two separate hydrostatic compartments. Evaluation of the models was based on ICP measurements at seven tilt-angles (0-71°)in 27 normal pressure hydrocephalus patients.
Results ICP decreased with tilt-angle (ANOVA, p<0.01). The reduction was well predicted by model III (ANOVA lack-of-fit: p=0.65), which showed excellent fit against measured ICP. Neither model I nor II adequately described the reduction in ICP (ANOVA lack-of-fit: p<0.01).
Conclusion Postural changes in ICP could not be predicted based on the currently accepted theory of a hydrostatic indifference point for the CSF system, but a new model combining Davson's equation for CSF absorption and hydrostatic gradients in a collapsible venous system performed well and can be useful in future research on gravity and CSF physiology.
Place, publisher, year, edition, pages
American Physiological Society , 2013. Vol. 115, no 10, 1474-1480 p.
intracranial pressure, spinal puncture, cerebrospinal fluid pressure, hydrocephalus, normal pressure, pulse pressure waves
IdentifiersURN: urn:nbn:se:umu:diva-82744DOI: 10.1152/japplphysiol.00711.2013PubMedID: 24052030OAI: oai:DiVA.org:umu-82744DiVA: diva2:662783
FunderSwedish Research Council, 221-2011-5216Vinnova