Influence of cerebral perfusion pressure and cardiac output on brain oxygenation and metabolism

Abstract The article contains results of examination of correlation between systemic hemodynamic and brain oxygenation and metabolism in patients with intracranial hemorrhage. Cardiac index (CI) and cerebral perfusion pressure (CPP) levels were compared to brain oxygenation and metabolism in 8 patients with intracranial hemorrhage (137 measurements). CI alterations didn't influence on PbrO2, glucose level or lactate/pyruvate ratio in the brain interstitial fluid in patients with traumatic brain injury. CPP elevation led to cerebral metabolism improvement. Optimal metabolic state was mentioned in CPP > 80 mm Hg. CPP elevation led to PbrO2 increasing in patients with subarachnoid hemorrhage due to aneurism rupture. This phenomenon can be explained by damage mechanisms of cerebral blood flow autoregulation. In these cases CI elevation was accompanied by worsening of aerobic metabolism in theoretically intact regions and improving it in injured brain regions.