Neuromonitoring

TCD-derived indices provide a quality metric for cerebral autoregulation and allow comparison with NIRS-derived indices. COx and HVx are calculated separately for each hemisphere as moving Pearson correlations between arterial blood pressure and rSO2. COx or HVx near zero indicates preserved autoregulation, while values near one indicate impaired pressure-passive perfusion. NIRS-derived rSO2 is treated as a clinically appropriate surrogate for cerebral blood flow in cerebral autoregulation monitoring. Intraoperative monitoring includes invasive arterial blood pressure and bilateral forehead NIRS sensors. TCD monitoring measures continuous cerebral blood flow velocity in both middle cerebral arteries when feasible.