Relationships Between Cerebral Perfusion Pressure and Regional Cerebral Blood Flow in Patients With Severe Neurological Disorders

Abstract

Three patients, one with a recurrent brain tumor, one with a severe brain contusion, and one with a brain abscess, are described who had continuous monitoring of the intracranial pressure with epidural and/or ventricular pressure transducers, continuous monitoring of the blood pressure, and periodic regional cerebral blood flow (rCBF) studies by the intra-arterial 133 Xenon method. A fourth patient with a severe brain contusion is described who had only blood pressure monitoring and rCBF studies. By measuring the regional cerebral blood flow and by testing autoregulation through changes in cerebral perfusion pressure and arterial P CO 2 , it is possible to reveal critical levels of cerebral perfusion pressure in the supratentorial compartment. Such measurements allow more rational evaluation of methods for control of increased intracranial pressure. The data point out that monitoring of systemic cardiorespiratory parameters for signs of cerebral compression is generally inadequate. The fact that pressure gradients may exist within the craniospinal enclosure is discussed. For this reason, before valid conclusions can be made regarding brain stem circulatory impairment at the tentorium and in the posterior fossa, the present regional techniques must be applied to these compartments also.