EFFECTS OF VARIATIONS IN ARTERIAL PRESSURE AND ARTERIAL CARBON DIOXIDE TENSION ON THE CEREBROSPINAL FLUID PRESSURE-VOLUME RELATIONSHIPS

Abstract

The influence of induced changes in arterial blood pressure and pCO2 on the pressure-volume characteristics of the cerebrospinal fluid space, was evaluated experimentally using dogs. The pressure-volume curve was not appreciably affected by variations in pCO2. The arterial pressure, on the contrary, was found to be a major determinant of the gradient dP/dV of the steep part of the curve, i.e. the high pressure elastance of the system. Variations in mean arterial pressure in the interval 25-230 mmHg produced approximately a 5-fold change in the elastance. The relationship was nonlinear, with relatively less effect from changes in the arterial blood pressure in the higher pressure range. An interpretation on the mechanics involved is presented.