Pressure volume relation in patients with subarachnoid haemorrhage and diffuse cerebral vasospasm

Seven patients, presenting severe neurological status (grades IV and V according to Hunt and Hess) and cerebral vasospasm following subarachnoid haemorrhage were submitted to continuous ICP recording the study of the cerebral elastic properties by PVI compliance computation. All the patients presented low ICP values (below 20 mmHg) for the whole period of monitoring. The results of PVI and compliance measurements show that the pressure-volume curves in these patients are different from the physiological P-V curve. The PVI values progressively increase with the rise in ICP. The significance of this finding is discussed.