title: Hypocapnia and intracranial volume-pressure relationship. A clinical and experimental study.
abstract: The effect of induced hypocapnia was observed, during intraventricular pressure monitoring, in five patients with chronically increased intracranial pressure (ICP) and in five baboons with acutely raised ICP. The volume-pressure response (VPR) was used as a measure of intracranial elastance (inverse compliance), an index of residual compensatory capacity. The VPR is the acute increase in mean ICP that occurs in response to a constant volume increment to ventricular cerebrospinal fluid. In the patients, hypocapnia produced a decrease in the VPR that was proportional to the decrease in ICP; in the baboons, ICP was substantially decreased with minimal change in the VPR. Both observations indicate that hypocapnia, though it decreases ICP, does not selectively decrease intracranial elastance. This may be a limiting factor in the use of hypocapnia in the management of raised ICP.
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001932:Brain Neoplasms / Q000150:complications; D002245:Carbon Dioxide / Q000097:blood*; D002555:Cerebrospinal Fluid / Q000502:physiology; D002560:Cerebrovascular Circulation; D002908:Chronic Disease; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology*; D007427:Intracranial Pressure; D010211:Papilledema / Q000150:complications; D010215:Papio
chemical_list: D002245:Carbon Dioxide