CPP and brain O 2 is not observed in every patient, in large part because autoregulation frequently is disturbed. 39 Results from recent studies have also demonstrated that an increase in brain tissue PO 2 is associated with improved cerebral metabolism. 32, 45 Together these data indicate that it is reasonable to assume that the use of a brain tissue PO 2 monitor and efforts to increase brain O 2 delivery may improve TBI outcome. Brain Tissue PO 2 —Guided Therapy and Outcome Results of this study demonstrate that brain tissue PO 2 —guided treatment is