It has been shown that cerebral oxygen consumption and blood flow are normal and cerebral vascular resistance is increased in patients with essential hypertension (1). Clinicians have questioned the advisability of lowering arterial pressures in hypertensive patients because of the possible untoward effects consequent to decreased cerebral blood flow (2, 3). We have studied the effect of hypote...

1. Cerebral blood flow, oxygen and glucose consumption, hind-limb blood flow and oxygen consumption, blood pressure and heart rate were measured in seven ventilated dogs. 2. Inhalation of 5% C 0 2 caused a significant increase in cerebral blood flow and a significant decrease in cerebral glucose utilization. 3. Isoprenaline infusion (0.4 pg kg-I min-') caused a rise in cerebral blood flow, oxyg...

We studied the effects of removal of the superior cervical sympathetic ganglion on cerebral blood flow and vascular reactivity to adrenergic agonists and antagonists in 11 unanesthetized goats. Cerebral blood flow was measured by an electromagnetic flow transducer previously implanted on the internal maxillary artery. Ganglionectomy produced an increase of 66 ± 8.26% (SEM) in cerebral blood flo...

BACKGROUND It has been suggested that a moving correlation index between mean arterial blood pressure and intracranial pressure, called PRx, can be used to monitor and quantify cerebral vasomotor reactivity in patients with head injury. OBJECTIVES To validate this index and study its relation with cerebral blood flow velocity and cerebral autoregulation; and to identify variables associated w...

Lidoflazine, a calcium channel blocker, was administered to dogs following twelve minutes of cerebral ischemia, induced by aortic cross-clamping. The effects of lidoflazine (1 mg/kg i.v.) on cerebral blood flow following ischemia was studied in 15 anesthetized, mechanically ventilated dogs. Cerebral blood flow was measured with the radiolabelled microsphere technique before and 10, 30, 60, 90 a...

The effect of chronic renovascular hypertension on the autoregulation of cerebral blood flow was studied in anesthetized baboons. Cerebral blood flow was measured by the intracarotid 133Xe clearance method. Six baboons with renal hypertension of 8-12 weeks' duration were compared with six normotensive controls. The lower limit of autoregulation was determined following controlled hemorrhage. In...

Cerebral blood flow was measured in eight patients who were being treated with dopamine in order to maintain cerebral perfusion after the onset of delayed postoperative ischaemia following intracranial aneurysm surgery. Measurements were made whilst on treatment and repeated either during a reduction in the dosage or withdrawal of dopamine. There was a significant fall in cerebral blood flow in...

The control of cerebral blood flow is complex, and only beginning to be elucidated. Studies have identified three key regulatory paradigms. The first is cerebral pressure autoregulation, which maintains a constant flow in the face of changing cerebral perfusion pressure. Flow-metabolism coupling refers to the brains ability to vary blood flow to match metabolic activity. An extensive arborizati...

Cerebral blood flow was measured by xenon-133 washout in 13 patients 6-46 hours after being resuscitated from cardiac arrest. Patients regaining consciousness had relatively normal cerebral blood flow before regaining consciousness, but all patients who died without regaining consciousness had increased cerebral blood flow that appeared within 24 hours after resuscitation (except in one patient...