Monitoring cerebral blood flow pressure autoregulation in pediatric patients during cardiac surgery

The limits of cerebral blood flow-pressure autoregulation have not been adequately defined for pediatric patients. Mean arterial blood pressure below these limits might contribute to brain injury during cardiac surgery. The purpose of this pilot study was to assess a novel method of determining the lower limits of pressure autoregulation in pediatric patients supported with cardiopulmonary bypass. A prospective, observational pilot study was conducted in children (n=54) undergoing cardiac surgery with cardiopulmonary bypass for correction of congenital heart defects. Cerebral oximetry index (COx) was calculated as a moving, linear correlation coefficient between slow waves of arterial blood pressure and cerebral oximetry measured with near-infrared spectroscopy. An autoregulation curve was constructed for each patient with averaged COx values sorted by arterial blood pressure. Hypotension was associated with increased values of COx (P