Purpose: 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.
Methods: 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.
Results: 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).
Conclusions: 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.