Global Cerebral Edema and Brain Metabolism After Subarachnoid Hemorrhage

Background and Purpose-Global cerebral edema is common among patients with poor-grade subarachnoid hemorrhage and is associated with poor outcome. Currently no targeted therapy exists largely due to an incomplete understanding of the underlying mechanisms. Methods-This is a prospective observational study including 39 consecutive patients with poor-grade subarachnoid hemorrhage with multimodal neuromonitoring. Levels of microdialysate lactate-pyruvate ratio, episodes of cerebral metabolic crisis (lactate-pyruvate ratio >40 and brain glucose <0.7 mmol/L), brain tissue oxygen tension, cerebral perfusion pressure, and transcranial Doppler sonography flow velocities were analyzed. Results-Median age was 54 years (range, 45 to 61 years) and 62% were female. Patients with global cerebral edema on admission (n = 24 [62%]) had a higher incidence of metabolic crisis in the first 12 hours of monitoring (n = 15 [15% versus 2%], P < 0.05) and during the total time of neuromonitoring (20% versus 3%, P < 0.001) when compared to those without global cerebral edema. There was no difference in brain tissue oxygen tension or cerebral perfusion pressure between the groups; however, in patients with global cerebral edema, a higher cerebral perfusion pressure was associated with lower lactate-pyruvate ratio (P < 0.05). Episodes of metabolic crisis were associated with poor outcome (modified Rankin Scale score 5 or 6, P < 0.05). Conclusions-In patients with poor-grade subarachnoid hemorrhage, global cerebral edema is associated with early brain metabolic distress. (Stroke. 2011;42:1534-1539.)