95 Continuous Recording of Cerebral Ventricular Fluid Pressure in Hydrocephalic Children

Abstract

To quantitate physiologic variations in and the effect of chemical agents on cerebral intraventricular pressure a technique for continuous pressure recording via an indwelling ventricular catheter and strain gauge transducer has been developed. Pressure studies for periods up to 10 days have been made on 12 hydrocephalic children ranging in age from 3 weeks to 5 years. Baseline recordings extending over 24 to 96-hour periods revealed multiple patterns of rhythmic variation with mean pressures ranging from 280 to 50 mm of water. Other physiologic parameters studied included respiratory rate and pattern, electrocardiogram and scalp venous pressure. Serum and ventricular fluid electrolyte and osmolar concentrations have been monitored. Ten of 11 children given oral isosorbide showed an immediate decrease in ventricular pressure ranging from 53 to 100 % of baseline similar to the effect of mannitol and urea. Ventricular wave form flattened during periods of pressure reduction. Five patients studied were also given acetazolamide, urea and mannitol. Acetazolamide increased ventricular pressure 2 to 3 fold with a concommitant exaggeration of pressure wave form. This hypertensive effect was immediate and persisted 2 to 4 hours before returning to baseline levels. Pressure studies were done under relatively isometric, not open manometric, conditions. Studies done with the ventricular fluid system open to flow at various levels of pressure show an early increase and a delayed decrease in cerebrospinal fluid formation with acetazolamide compared to a decrease in flow following isosorbide. (APS)