Cerebrospinal Fluid Pulse Pressure Research Articles

On the Pathology of Experimental Hydrocephalus Induced by Artificial Increase in Endoventricular CSF Pulse Pressure

In lambs, acute and chronic communicating hydrocephalus has been created by merely increasing the amplitude of the intraventricular cerebrospinal fluid (CSF) pulsations, leaving the mean CSF pressure unchanged. The pathologic changes occurring in this type of hydrocephalus do not differ qualitatively from those observed in obstructive hydrocephalus. Beside demonstrating a direct role of ventricular pulsations in the ventricular dilation, the observed findings indicate that an increase in mean CSF pressure is not a necessary condition for the occurrence of the hydrocephalus. Consequently, the hypothesis of abnormal high intraventricular CSF pressure oscillations at the basis of the ventricular dilation of normal pressure hydrocephalic patients, receives a significant support. Further support is provided is provided by considering the recorded experimental pathological lesions are quite similar to those observed in normal pressure hydrocephalic patients with patent subarachnoid CSF pathways.

Communicating hydrocephalus induced by mechanically increased amplitude of the intraventricular cerebrospinal fluid pulse pressure: Rationale and method

The effect of increasing the amplitude of the intraventricular cerebrospinal fluid (CSF) pulse pressure in lambs was studied in acute experiments. The intraventricular CSF pulse pressure was mechanically increased by a device which rhythmically inflated and deflated an intraventricular balloon synchronously with the cardiac rate. No variation in mean intraventricular CSF pressure was recorded following the increase in CSF pulse pressure. The neuropathological findings indicated a direct pathogenic effect on periventricular structures exerted by the intraventricular CSF pulsations, which were increased to three to six times the normal values.

A device for increasing the amplitude of the pulse pressure of cerebrospinal fluid

In order to analyze the effect of increasing CSF pulse pressure a device has been designed which delivers to CSF pulsations of variable amplitude and synchronous with the CSF arterial oscillations. The R wave of the ECG triggers a circuit which provides a square wave of adjusted duration and selected delay. This wave drives a unit which controls the power supply to electromagnetic pump.

Cerebrospinal Fluid Pressure Studies in Normal Pressure Hydrocephalus and Cerebral Atrophy

The surgical results obtained with a cerebrospinal fluid (CSF) shunt operation in 13 patients considered to be suffering from normal pressure hydrocephalus have been correlated with the findings of the constant manometric infusion test (IT) and of prolonged intracranial pressure recordings. A positive IT, high amplitude CSF pulse pressure and large transitory increases of CSF pressure during sleep seem to be useful criteria for the surgical prognosis. Ten more patients affected by primary cerebral atrophy have also been studied. The data obtained in both groups of patients have been utilized for a possible pathogenetic interpretation of the syndrome.

Cerebrospinal fluid pulse pressure and brain compliance in adult cats.

Cerebrospinal fluid (CSF) pulse pressure was inversely proportional to a brain compliance determined from artificial CSF pulsations generated by an external pump. Brain compliance was 0.71 cu mm/mm H2O at steady-state CSF mean pressure and decreased 50 percent for each 240 mm H2O increase in CSF mean pressure (mean results of duplicate experiments on 10 adult cats). Both CSF pulse pressure and the time course of transient changes in CSF mean pressure could be described in terms of a model of the CSF circulation consisting of a constant resistance to CSF absorption in parallel with a pressure-dependent brain compliance.

Influence of changes in cerebral blood flow on the cerebrospinal fluid pressure.

WE HAVE previously reported that changes in cerebral blood flow may have a profound effect in the same direction on the cerebrospinal fluid pressure of rhesus monkeys. 1 The present communication deals with this relationship in man. MATERIAL AND METHODS The types of patients studied and the methods of continuously recording the several pressures of interest have been described. 2 Included in this study are patients who were sufficiently cooperative to hyperventilate and lie quietly. OBSERVATIONS The administration of carbon dioxide in air increases the cerebral blood flow 3 and the cerebrospinal fluid pressure. 4 Hyperventilation decreases the flow 5 and the fluid pressure. 4 The cerebrospinal fluid pulse pressure varies concomitantly with the irregular arterial pulses of auricular fibrillation and extrasystoles. These procedures and conditions usually cause concomitant changes in the arterial pressure in the same direction, which have been assumed by other investigators to be the causative mechanism,