Intracerebral monitoring of silent infarcts after subarachnoid hemorrhage.

Background: Silent infarction is common in poor-grade subarachnoid hemorrhage (SAH) patients and associated with poor outcome. Invasive neuromonitoring devices may detect changes in cerebral metabolism and oxygenation.

Methods: From a consecutive series of 32 poor-grade SAH patients we identified all CT-scans obtained during multimodal neuromonitoring and analyzed microdialysis parameters and brain tissue oxygen tension (PbtO2) preceding CT-scanning.

Results: Eighteen percent of the reviewed head-CTs (12/67) revealed new infarcts. Of the eight infarcts in the vascular territory of the neuromonitoring, seven were clinically silent. Neuromonitoring changes preceding radiological evidence of infarction included lactate-pyruvate-ratio elevation and brain glucose decreases when compared to those with distant or no ischemia (P ≤ 0.03, respectively). PbtO2 was lower, but this did not reach statistical significance.

Conclusions: These data suggest that there may be distinct changes in brain metabolism and oxygenation associated with the development of silent infarction within the monitored vascular territory in poor-grade SAH patients. Larger prospective studies are needed to determine whether treatment triggered by neuromonitoring data has an impact on outcome.