NIRS and BIS Monitoring During Cerebral Aneurysm Coiling

Cerebral aneurysm coil embolization carries a potential risk of cerebral hypoperfusion and ischemia during the intraoperative period. Near-Infrared Spectroscopy (NIRS) provides continuous, non-invasive monitoring of regional cerebral oxygen saturation, while Bispectral Index (BIS) allows assessment of anesthetic depth. In this prospective observational study, adult patients undergoing endovascular coil embolization for cerebral aneurysms under general anesthesia will be monitored using standard anesthesia monitoring, including NIRS and BIS, which are part of routine clinical practice at the study center. Baseline NIRS and BIS values will be recorded prior to anesthetic induction, followed by continuous intraoperative monitoring at predefined time points. A decrease of ≥20% from baseline rSO₂ will be defined as clinically significant cerebral desaturation. Relationships between NIRS values, BIS measurements, and hemodynamic parameters will be evaluated. The study aims to contribute to the understanding of multimodal neuromonitoring during neuroendovascular procedures and to support clinical decision-making regarding cerebral protection strategies.