Cerebral circulation and metabolism in uremia.

Data on 16 patients with uremia are presented. The cerebral blood flow was moderately decreased in patients with generalized vascular disease, but was normal in patients with minimal vascular involvement. In both groups the cerebral oxygen consumption (cerebral metabolic rate in terms of oxygen consumption, CAIRO,) was reduced significantly and to the same degree. In contrast, total body metabolism was not demonstrably reduced. These facts emphasize the vulnerability of the brain to uremia. There was poor correlation between the cerebral oxygen utilization and the pa-tient's mental state. No correlation was found between the cerebral oxygen consumption and the blood nonprotein nitrogen, the carbon dioxide capacity, or the sodium, potassium or chloride levels. LITTLE information is available as to the specific factors responsible for the neuro-logic and mental symptoms associated with uremia." 2 The extensive histologic changes in the brain' and the increase in intracranial pressure sometimes seen in patients with the uremic syndrome may account to some extent for these neurologic abnormalities. With such changes, alterations in cerebral circulation and metabolism are to be anticipated. This paper presents observations on the cere-bral blood flow and oxygen consumption in 16 patients with uremia. An attempt is made to correlate alterations in these functions with the mental status of the patient, the etiology of the uremia, and the derangement of the chemical structure of the blood.