Optimal brain perfusion pressure derived from the continuous monitoring of cerebral autoregulation status during neonatal heart surgery under cardiopulmonary bypass in relation to brain injury: An observational study

Background

Understanding cerebral blood flow regulation and later optimizing brain perfusion is part of neuroprotection during cardiopulmonary bypass (CPB) in neonates.

Methods

A total of 38 neonates undergoing CPB were monitored using near-infrared spectrometry and mean arterial pressure (MAP). Cerebral autoregulation (CAR) was assessed through the continuous measurement of the Cerebral Oxygenation Index (COx), and CAR-derived metrics were determined by plotting averaged COx values by MAP: Optimal MAP (MAPopt), lower limit of CAR (LLA), upper limit of CAR (ULA).

Results

Out of 38, 17 (45%) neonates exhibited moderate to severe brain lesions post-operatively. The onset of CPB was associated with CAR disruption (mean COx pre-CPB = 0.16 ± 0.11; during CPB: 0.39 ± 0.37, p < 0.001). A LLA was identified in 31 out of 38 (82%), 23 out of 38 (61%), and 14 out of 38 (37%) patients before, during, and after CPB, respectively. An ULA was identified in 29 out of 38 (76%), 22 out of 38 (58%), and 14 out of 38 (37%) patients in the same time frames. Patients with abnormal post-operative brain MRI spent more time below the LLA during CPB: 28.3% [17.1–32.9] versus 9.9% [6.9–18.5] in patients without detected brain injury, p = 0.039. No differences were observed regarding the time spent above the upper limit of autoregulation.

Conclusion

The study provides valuable insights into the intricate relationship between intraoperative cerebral hemodynamics and post-operative brain injury. Further research is warranted to explore potential interventions based on CAR-derived metrics during CPB in neonates.

Clinical trial registration number

Not applicable.

Prior presentation

Not applicable.