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A mathematical model of the cerebrospinal fluid (CSF) system was developed to help clarify the kinetics of the intracranial pressure (ICP). A general equation predicting the time course of pressure was derived in terms of four parameters: the intracranial compliance, dural sinus pressure, resistance to absorption, and CSF formation. These parameters were(More)
The distribution of compliance and outflow resistance between cerebral and spinal compartments was measured in anesthetized, ventilated cats by analysis of the cerebrospinal fluid (CSF) pressure response to changes in CSF volume. Cerebral and spinal compartments were isolated by inflating a balloon positioned epidurally at the level of C-6. The change of(More)
The pressure-volume index (PVI) technique was used to measure neural axis compliance, cerebrospinal fluid (CSF) formation (If), and CSF absorption (Ro) in 23 children and 7 adults, all free from intracranial masses, who were undergoing diagnostic or therapeutic procedures. Using bolus manipulation of CSF, If was 0.36 +/- 0.08 ml/min and Ro was 2.8 +/- 0.8(More)
A simple method was developed for the laboratory preparation of gradient columns of specific gravity used in measurement of brain-tissue water. By this automated technique, virtually linear and repeatable density gradients were obtained from which values of tissue specific gravity could be determined. The specific gravity of both solid and fresh cortex and(More)
Significant errors are introduced into the measurement of brain tissue water by the specific gravity technique when the edema fluid contains protein. Protein adds to the tissue solids, increasing the density of the tissue, and masks the proportional increase of brain water. Existing equations relating measured specific gravity and tissue water are not(More)
Brain edema represents a disturbance of the volume equilibrium which, in the early stages of formation, must be compensated for by a reduction in other fluid and blood compartments. When this compensation is inadequate, tissue pressure and intracranial pressure increase, the magnitude of which depends on the compliance of the tissue. Tissue pressure(More)