Non-invasive cerebral oxygenation and blood pressure neuromonitoring characterizes dynamic cerebrovascular autoregulation following cardiac arrest.

Background and purpose: Cerebrovascular autoregulation (CVAR) is impaired following cardiac arrest. We describe near-infrared spectroscopy (NIRS)-derived CVAR parameters following cardiac arrest and characterize their evolution over time. Methods: This was a retrospective analysis of a prospectively collected clinical and physiological cardiac arrest data repository at a single academic medical center between March 2022 and October 2023. Eligible patients were connected to neuromonitoring within 72 h of cardiac arrest, had greater than four hours of monitoring, and had no confounding neurologic diagnosis. NIRS derived cerebral oxygenation index (COx) and limits of autoregulation were computed using the linear correlation between time-synchronized regional cerebral oxygenation (rSO Results: Of 60 eligible patients, 56 underwent neuromonitoring, and 55 were included in this analysis. Mean (standard deviation [SD]) age was 53.4 (15.4) years, and the majority had high severity of post-cardiac arrest syndrome. The median (interquartile range) time from cardiac arrest to first recorded COx was 14.2 (10.1-21.2) h; median monitoring duration was 49.1 (26.6-85.3) h. Mean (SD) MAP Conclusion: Impaired CVAR was common and dynamic over at least 120 h following cardiac arrest. If a population-based MAP threshold of ≥65 mmHg were applied to our cohort, it may have resulted in significant time burden below the LLA. While it was feasible to determine CVAR limits, further work is needed to identify if CVAR-based treatment approaches influence outcomes.