Cerebral Metabolic Rate of Oxygen (CMRO2) in the Acute Phase of Brain Injury

In 22 comatose patients with acute brain injury, the cerebral metabolic rate of oxygen (CMRO2) was calculated as the product of the hemispheric cerebral blood flow (CBF) and the arteriovenous oxygen content difference. All patients were subjected to moderate sedation without barbiturates, normothermia and respiratory treatment. The CBF was calculated by the 133xenon washout method as the average of 16 regions. The results indicate high jugular venous oxygen tension and, in some studies, very low oxygen consumption. A critical, low CMRO2 was not found, and values of about 0.4 ml/100 g/min were compatible with restitution of intellectual function. The CMRO2 was unrelated to the clinical outcome and to the time after the trauma. In bilateral studies, the lowest values were measured in the most severely injured hemisphere.