Discrete cerebral oximetry measurements and the potential contribution of hemolysis to circulating neuron-specific enolase after pediatric cardiac surgery

Wang and colleagues reported an association between the minimum of three intraoperative regional cerebral oxygen saturation measurements and peak plasma neuron-specific enolase in infants aged ≤ 6 months undergoing cardiac surgery. Two issues warrant consideration. Hemolysis related to cardiopulmonary bypass may affect circulating neuron-specific enolase independently of neuronal injury, but whether hemolysis influenced the reported association cannot be determined. Describing the minimum of three discrete measurements as a nadir may imply continuous ascertainment. These measurements cannot characterize transient desaturation, duration below threshold, or cumulative hypoxic burden. Individual hemolysis measures and continuous cerebral oximetry could clarify the reported association.