[Test of non-invasive PVI measure with a fiber-optic pressure monitoring device in head injured patients].

At present, method for determining pressure volume status in head injured patients must be obtained via analysis of pressure response to bolus injections into the ventricular catheter system. The concept introduced by Bray of extracting Pressure Volume Index (PVI) measures from analysis of the pulse pressure centroid presents a less invasive technique and provides PVI data continuously. The objective of this study was to test the application of the system which incorporated the Bray concept to PVI measures in head injured patients. The centroid of frequency power spectrum was provided continuously by a computer system linked to the bedside monitor. The computer incorporated the Bray concept for PVI estimation. These values were compared with PVI measured by conventional bolus technique. We tested the system using ICP pulsating wave form delivered from a fiberoptic pressure monitoring system in brain tissue in two different band-width (Narrow band-width: 4-8 Hz, Wide band-width: 4-15 Hz). PVI studies using bolus fluid injection or withdrawal were conducted at least twice a day and usually each study consisted of 3 to 6 injections or withdrawals to obtain a study average PVI. These study average were correlated with the centroid obtained during the same study interval in 17 head injured patients of Glasgow Coma Scale (GCS) 8 or less. The correlation of the centroid and PVI in the wide band-width group was significant (p less than 0.01, r = 0.77), however, in the narrow band-width group, the correlation was not significant (r = 0.07, N.S.).(ABSTRACT TRUNCATED AT 250 WORDS)