Cerebral Autoregulation monitoring using Cerebral Oximetry index after neonatal cardiac surgery: a single-center retrospective cohort study.

OBJECTIVE: The aims of this study are to investigate whether cerebral autoregulation is impaired after neonatal cardiac surgery and if changes in autoregulation metrics are associated with different congenital heart defects or the incidence of postoperative neurological events.

METHODS: This is a retrospective observational study on neonates undergoing monitoring during the first 72 hours after cardiac surgery. Archived data were processed to calculate cerebral oximetry index and derived metrics. Acute neurologic events were identified by electronic medical records review. The Skillings-Mack test and the Wilcoxon signed-rank test were used to analyze the evolution of autoregulation metrics over time; the Mann-Whitney U test was used for comparison between groups.

RESULTS: We included 28 neonates, 7 (25%) with Hypoplastic Left Heart Syndrome and 21 (75%) with Transposition of the Great Arteries. Overall, the median of percentage of time spent with impaired autoregulation, defined as percentage of time with cerebral oximetry index >0.3, was 31.6% (IQR=21.1-38.3). No differences in autoregulation metrics between different cardiac defects subgroups were observed. Seven patients (25%) experienced postoperative acute neurologic events. Patients with acute neurologic events showed higher cerebral oximetry index (0.16 vs.0.07 p=0.035), higher percentage of time with cerebral oximetry index >0.3 (39.4% vs.29.2% p=0.017) and higher percentage of time with mean arterial pressure below the lower limit of autoregulation (13.3% vs. 6.9% p=0.048) than those without acute neurologic events.

CONCLUSIONS: Cerebral oximetry index monitoring after cardiac surgery allowed the detection of impaired cerebral autoregulation, which was more frequent in neonates with postoperative acute neurologic events.