Perioperative amplitude-integrated EEG and neurodevelopment in infants with congenital heart disease

Perioperative brain injury is common in young infants undergoing cardiac surgery. We aimed to determine the relationship between perioperative electrical seizures, the background pattern of amplitude-integrated electroencephalography (aEEG) and 2-year neurodevelopmental outcome in young infants undergoing surgery for congenital heart disease. A total of 150 newborn infants undergoing cardiac surgery underwent aEEG monitoring prior to and during surgery, and for 72 h postoperatively. Two blinded assessors reviewed the aEEGs for seizure activity and background pattern. Survivors underwent neurodevelopmental outcome assessment using the Bayley Scales of Infant Development (3rd edn.) at 2 years. The median age at surgery was 7 days (IQR 4-11). Cardiopulmonary bypass was used in 83 %. Perioperative electrical seizures occurred in 30 %, of whom 1/4 had a clinical correlate, but were not associated with 2-year outcome. Recovery to a continuous background occurred at a median 6 (3-13) h and sleep-wake cycling recovered at 21 (14-30) h. Prolonged aEEG recovery was associated with increased mortality and worse neurodevelopmental outcome. Failure of the aEEG to recover to a continuous background by 48 postoperative hours was associated with impairment in all outcome domains (p < 0.05). Continued abnormal aEEG at 7 postoperative days was highly associated with mortality (p < 0.001). Perioperative seizures were common in this cohort of infants but did not impact on 2-year neurodevelopmental outcome. Delayed recovery in aEEG background was associated with increased risk of early mortality and worse neurodevelopment. Ongoing monitoring of the survivors is essential to determine the longer-term significance of these findings.