Distribution of Intracranial Contents with Controlled Hyperventilation

Abstract

The distribution of the intracranial contents was determined during controlled hyperventilation to an arterial pH of 7.59 and a PCO2 of 20 mm of mercury. A decrease in intracranial blood volume was found and a compensatory increase in cerebrospinal fluid volume. No change was seen in either brain water or brain solids, nor was there a decline in cerebrospinal fluid pressure. It was concluded that controlled hyperventilation does not reduce the volume of brain tissue, and intracranial pressure is not affected if the blood CO2 tension is normal prior to the onset of ventilation.