Intracranial volume-pressure relationship in man

1982 ◽  
Vol 56 (4) ◽  
pp. 524-528 ◽  
Author(s):  
Joseph Th. J. Tans ◽  
Dick C. J. Poortvliet
Keyword(s):  
Best Approximation ◽  
Continuous Monitoring ◽  
Fluid Pressure ◽  
Constant Term ◽  
Volume Index ◽  
Intracranial Volume ◽  
Content Type ◽  
The Best Approximation ◽  
Ventricular Fluid Pressure ◽  
Fine Print

✓ The pressure-volume index (PVI) was determined in 40 patients who underwent continuous monitoring of ventricular fluid pressure. The PVI value was calculated using different mathematical models. From the differences between these values, it is concluded that a monoexponential relationship with a constant term provides the best approximation of the PVI.

Intracranial volume-pressure relationship in man

1983 ◽  
Vol 59 (5) ◽  
pp. 810-816 ◽  
Author(s):  
Joseph Th. J. Tans ◽  
Dick C. J. Poortvliet
Keyword(s):  
Continuous Monitoring ◽  
Fluid Pressure ◽  
Pressure Rise ◽  
Intracranial Volume ◽  
Content Type ◽  
Intensive Monitoring ◽  
Therapeutic Consequences ◽  
Ventricular Fluid Pressure ◽  
The Relationship ◽  
Fine Print

✓ Pressure-volume indices (PVI's) were determined for a heterogeneous group of 40 patients who underwent continuous monitoring of ventricular fluid pressure (VFP). The main purpose was to investigate the relationship between VFP and PVI and to establish the significance of the measured PVI values. Determinations of PVI appear to be useful only when baseline VFP is under 20 mm Hg, maximum VFP is under 30 mm Hg, A-waves are absent, and B-waves do not occur numerously. The authors advocate starting with 1-ml bolus infusions, and then, when the resulting pressure rise exceeds 4 mm Hg, additional bolus infusions can be omitted. Results indicate that 13 ml and 10 ml are the key values for the PVI. A PVI of less than 13 ml indicates the need for either reduction of VFP and improvement of compliance or intensive monitoring of both the VFP and the volume-pressure relationship; if the PVI is below 10 ml, anti-hypertensive treatment is almost always necessary. Values of PVI's between 13 and 18 ml, although pathological, usually have no therapeutic consequences.

A clinical comparison of subdural screw pressure measurements with ventricular pressure

1983 ◽  
Vol 58 (1) ◽  
pp. 45-50 ◽  
Author(s):  
A. David Mendelow ◽  
John O. Rowan ◽  
Lilian Murray ◽  
Audrey E. Kerr
Keyword(s):  
Head Injury ◽  
Intracranial Pressure ◽  
Severe Head Injury ◽  
Fluid Pressure ◽  
Ventricular Catheter ◽  
Pressure Measurements ◽  
Content Type ◽  
Single Lumen ◽  
Ventricular Fluid Pressure ◽  
Fine Print

✓ Simultaneous recordings of intracranial pressure (ICP) from a single-lumen subdural screw and a ventricular catheter were compared in 10 patients with severe head injury. Forty-one percent of the readings corresponded within the same 10 mm Hg ranges, while 13% of the screw pressure measurements were higher and 46% were lower than the associated ventricular catheter measurements. In 10 other patients, also with severe head injury, pressure measurements obtained with the Leeds-type screw were similarly compared with ventricular fluid pressure. Fifty-eight percent of the dual pressure readings corresponded, while 15% of the screw measurements were higher and 27% were lower than the ventricular fluid pressure, within 10-mm Hg ranges. It is concluded that subdural screws may give unreliable results, particularly by underestimating the occurrence of high ICP.

Effects of intravenous nitroglycerin on the intracranial pressure and volume pressure response

1983 ◽  
Vol 58 (4) ◽  
pp. 562-565 ◽  
Author(s):  
Ghaleb A. Ghani ◽  
Yung Fong Sung ◽  
Michael S. Weinstein ◽  
George T. Tindall ◽  
Alan S. Fleischer
Keyword(s):  
Blood Pressure ◽  
Intracranial Pressure ◽  
Fluid Pressure ◽  
Pressure Response ◽  
Mean Blood Pressure ◽  
Intravenous Nitroglycerin ◽  
Content Type ◽  
Ventricular Fluid Pressure ◽  
The Mean ◽  
Fine Print

✓ Ventricular fluid pressure (VFP) and volume-pressure response were measured during nitroglycerin (NTG) infusion in nine patients anesthetized with N2O and fentanyl. The patients' ventilation was controlled, and PaCO2 was kept at 32 ± 4 mm Hg. When an infusion of 0.01% NTG was given intravenously to decrease the mean blood pressure to 95.1%, 84.7%, and 78.2% of control, the VFP increased from control levels of 9.94 ± 2.14 mm Hg to 12.89 ± 2.25, 15.6 ± 2.85, and 14.43 ± 3.45 mm Hg, respectively. The volume-pressure response showed a significant increase when blood pressure decreased to 84.7% and 78.2% of control. These results suggest that intravenous NTG caused an increase in the intracranial pressure and a decrease in the intracranial compliance.

Intracranial physiology and biomechanics

1982 ◽  
Vol 57 (4) ◽  
pp. 500-510 ◽  
Author(s):  
Eugeny I. Paltsev ◽  
Edward B. Sirovsky
Keyword(s):  
Brain Function ◽  
Quantitative Data ◽  
Fluid Pressure ◽  
Fluid Injection ◽  
Intracranial Volume ◽  
Clinical Tests ◽  
Content Type ◽  
Minimal Error ◽  
Active Compliance ◽  
Ventricular Fluid Pressure

✓ The intracranial pressure-volume (PV) relationship was examined postoperatively after removal of brain tumors in two groups of patients (13 in all). Changes of ventricular fluid pressure were analyzed by a method involving fluid injection into the lateral ventricle. A technique has been developed which provides quantitative data on the PV relationship with minimal error. The results confirm the exponential nature of the PV relationships. Various parameters characterizing the intracranial volume compliance, the cerebrospinal fluid pressure, and their interrelationship were investigated. It was found that 1) intracranial PV dependence is accurately defined by three parameters; 2) in patients who are not critically ill, ΔP/ΔV at P = Pmean does not vary statistically, and may be used as one of the important parameters to determine the regulation of the intracranial PV relationships. Examples are presented of the use of the data from the PV test for the control of the intracranial PV relationship. Examples are also given of the computation of volume redistribution in the cranium, both spontaneous and evoked by clinical tests. Analysis of the results allows the conclusion that the intracranial volume compliance concerned is an active compliance, which is controlled by the systems maintaining brain function.

Effects of mannitol and steroid therapy on intracranial volume-pressure relationships in patients

1975 ◽  
Vol 42 (3) ◽  
pp. 274-281 ◽  
Author(s):  
J. Douglas Miller ◽  
Peter Leech
Keyword(s):  
Intracranial Pressure ◽  
Intracranial Hypertension ◽  
Continuous Monitoring ◽  
Pressure Response ◽  
Pressure Curve ◽  
Intracranial Volume ◽  
Intraventricular Pressure ◽  
Content Type ◽  
Spatial Compensation ◽  
Fine Print

✓ The intracranial volume-pressure response was measured in 61 patients undergoing continuous monitoring of intraventricular pressure. This test, which determines the increase in intracranial pressure induced by an addition of 1 ml in ventricular CSF volume in 1 second, yields information concerning spatial compensation in patients with intracranial space-occupying processes. On the basis of variability tests, a change in volume-pressure response of 2 mm Hg/ml was accepted as significant. Pronounced enlargement of the ventricles interferes with the test. In patients with intracranial hypertension, intravenous mannitol (0.5 gm/kg) and intramuscular betamethasone (26 mg) both reduce the volume-pressure response significantly more than they reduce intracranial pressure. This suggests that these agents favorably alter the configuration of the volume-pressure curve.

Age-related changes in the proportion of intracranial cerebrospinal fluid space measured using volumetric computerized tomography scanning

2002 ◽  
Vol 97 (3) ◽  
pp. 607-610 ◽  
Author(s):  
Hiroshi Wanifuchi ◽  
Takashi Shimizu ◽  
Takashi Maruyama
Keyword(s):  
Cerebrospinal Fluid ◽  
Computerized Tomography ◽  
Ct Scanning ◽  
Volume Measurement ◽  
Intracranial Volume ◽  
Content Type ◽  
Standard Curve ◽  
Age Related ◽  
Fine Print ◽  
Age Related Changes

Object. The purpose of this study was to establish a standard curve to demonstrate normal age-related changes in the proportion of intracranial cerebrospinal fluid (CSF) space in intracranial volume (ICV) during each decade of life. Methods. Using volumetric computerized tomography (CT) scanning and computer-guided volume measurement software, ICV and cerebral parenchymal volume (CPV) for each decade of life were measured and the intracranial CSF ratio was calculated by the following formula: percentage of CSF = (ICV − CPV)/ICV × 100%. The standard curve for age-related changes in normal percentages of intracranial CSF was obtained. Conclusions. Based on this standard curve, the percentage of intracranial CSF rapidly increased after the sixth decade, seeming to reflect the brain atrophy that accompanies increased age.

Subtle deterioration in shunted childhood hydrocephalus

1986 ◽  
Vol 65 (2) ◽  
pp. 211-216 ◽  
Author(s):  
Arno Fried ◽  
Kenneth Shapiro
Keyword(s):  
Buffering Capacity ◽  
Volume Index ◽  
Shunt Revision ◽  
Pressure Waves ◽  
Ventricular Size ◽  
Csf Shunts ◽  
Content Type ◽  
The Mean ◽  
Childhood Hydrocephalus ◽  
Fine Print

✓ Eighteen hydrocephalic children who presented with subtle deterioration when their shunts malfunctioned were studied during shunt revision by means of the pressure-volume index (PVI) technique. Bolus manipulation of cerebrospinal fluid (CSF) was used to determine the PVI and the resistance to the absorption of CSF (Ro). Ventricular size was moderately to severely enlarged in all the children. Steady-state intracranial pressure (ICP) at the time of shunt revision was 17.5 ± 7.3 mm Hg (range 8 to 35 mm Hg). Pressure waves could not be induced by bolus injections in the 8- to 35-mm Hg range of ICP tested. The mean ± standard deviation (SD) of the predicted normal PVI for this group was 18.5 ± 2.7 ml. The mean ± standard error of the mean of the measured PVI was 35.5 ± 2.1 ml, which represented a 187% ± 33% (± SD) increase in volume-buffering capacity (p < 0.001). The ICP did not fall after bolus injections in three children, so that the Ro could not be measured. In the remaining 15 patients, Ro increased linearly as a function of ICP (r = 0.74, p < 0.001). At ICP's below 20 mm Hg, Ro ranged from 2.0 to 5.0 mm Hg/ml/min, but increased to as high as 21 mm Hg/ml/min when ICP was above 20 mm Hg. This study documents that subtle deterioration in shunted hydrocephalic children is accompanied by abnormally compliant pressure-volume curves. These children develop ventricular enlargement and neurological deterioration without acute episodic pressure waves. The biomechanical profile of this group differs from other children with CSF shunts.

Biomechanical and hydrodynamic characterization of the hydrocephalic infant

1985 ◽  
Vol 63 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Kenneth Shapiro ◽  
Arno Fried ◽  
Anthony Marmarou
Keyword(s):  
Steady State ◽  
Ventricular Volume ◽  
Volume Index ◽  
Injection Technique ◽  
Infantile Hydrocephalus ◽  
Content Type ◽  
Two Factors ◽  
The Mean ◽  
Fine Print

✓ The pressure-volume index (PVI) technique of bolus manipulation of cerebrospinal fluid (CSF) was used to measure neural axis volume-buffering capacity and resistance to the absorption of CSF in 16 hydrocephalic infants prior to shunting. The mean steady-state intracranial pressure (ICP) was 11.7 ± 5.7 mm Hg (± standard deviation (SD)), representing a modest elevation of ICP in infants. The mean measured PVI was 28.1 ± 1.5 ml (± standard error of the mean (SEM)) compared to the predicted normal level for these infants of 12.1 ± 2.7 ml (± SD) (p < 0.001). This resulted from an enhanced volume storage capacity in the hydrocephalic infants. The PVI was not related to ventricular size in these hydrocephalic infants. Although absorption of the additional bolus of fluid did not occur at steady-state ICP, it was readily absorbed once ICP was raised above a mean threshold pressure of 16.0 ± 5.0 mm Hg (± SD) in 13 of the 16 infants. Above this pressure, the mean CSF absorption resistance was 7.2 ± 1.3 mm Hg/ml/min (± SEM) which is twice the normal values as measured by the bolus injection technique. The biomechanical profile of infantile hydrocephalus described in this study indicates that two factors are required for progression of ventricular volume. While an absorptive defect may initiate the hydrocephalic process, progressive volume storage requires an alteration in the mechanical properties of the intracranial compartment.

Ventricular volume change in childhood

2002 ◽  
Vol 97 (3) ◽  
pp. 584-590 ◽  
Author(s):  
Chris Xenos ◽  
Spyros Sgouros ◽  
Kalyan Natarajan
Keyword(s):  
Statistical Difference ◽  
Linear Regression Analysis ◽  
Ventricular Volume ◽  
Intracranial Volume ◽  
Normal Children ◽  
Content Type ◽  
Ventricular Volumes ◽  
Significant Difference ◽  
The Mean ◽  
Fine Print

Object. The aim of this study was to construct a model of age-related changes in ventricular volume in a group of normal children ages 1 month to 15 years, which could be used for comparative studies of cerebrospinal fluid circulation disorders and cerebral atrophy developmental syndromes. Methods. A magnetic resonance imaging—based segmentation technique was used to measure ventricular volumes in normal children; each volume was then plotted against the child's age. In addition, intracranial volumes were measured and the ratio of ventricular to intracranial volume was calculated and plotted against age. The study group included 71 normal children, 39 boys and 32 girls, whose ages ranged from 1 month to 15.3 years (mean 84.9 months, median 79 months). The mean ventricular volume was 21.3 cm3 for the whole group, 22.7 cm3 in boys and 19.6 cm3 in girls (p = 0.062, according to t-tests). The mean ventricular volume at 12 months for the whole group was 17 cm3 (20 cm3 in boys and 15 cm3 in girls), representing 65% of the volume achieved by 15 years of age (87% in boys and 53% in girls). The volume increased by a factor of 1.53, to 26 cm3 (23 cm3 in males and 28 cm3 in females, increase factors of 1.15 and 1.86, respectively) at 15 years of age. The change in ventricular volume with age is not linear, but follows a segmental pattern. These age periods were defined as: 0 to 3, 4 to 6, 7 to 10, and 11 to 16 years. A statistical difference based on sex was only demonstrated in the first 6 years of life. The mean ventricular volume for the first 6-year period was 22.4 cm3 in boys and 15.7 cm3 in girls, and the difference was significant for the two sexes (linear regression analysis for age and sex, significant according to analysis of variance regression at 0.007, p = 0.108 for age, p = 0.012 for sex). Thereafter, there was no significant difference in ventricular volume between boys and girls with further growth. The ratio of ventricular volume to intracranial volume was 0.0175 for the whole group, 0.017 in boys and 0.018 in girls (p = 0.272, according to t-tests). At 12 months of age the ratio was 0.019; it stabilized to 0.015 at 8 years of age, and increased to 0.018 at 15 years of age. No statistical difference based on sex was demonstrated with growth. Conclusions. The ventricular volume in normal children increases with age by a factor of 1.5; the increase is in a nonlinear segmental pattern. Boys have significantly higher ventricular volumes only in the first 6 years of life. The ventricular/intracranial volume ratio remains stable throughout childhood.

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