Introduction: EEG seizures are seen in 11-20% of neonates undergoing cardiac surgery with CPB with low flow or circulatory arrest.(1,2) The objective of this study was to assess neonates for EEG seizures after surgery with high flow CPB and maximized cerebral oxygenation. The hypothesis was that EEG seizures would be minimized.

Methods: CPB protocol was 150-ml/kg/min flows, pH stat, hematocrit 30-35%, NIRS monitoring. Antegrade cerebral perfusion was used, DHCA was minimized. 10 lead neonatal EEG was used for 6 hour baseline EEG preoperatively, and 72 hours of continuous postoperative EEG.

Results: 68 patients were studied: 36 single ventricle, and 32 two ventricle. In 4968 hours of postoperative EEG, no 2V patients had seizures, and 2 SV patients had brief seizures, for an incidence of 2.9%. (p=0.49) A 30-second seizure occurred in a Norwood Stage I patient at hour 72, and another SV patient had a 30 second seizure at hour 7, and 95 second seizure at hour 10. (See Table). Both had prolonged rSO2 <45% (total of 2105 and 668 minutes) although low rSO2 was not associated with EEG seizures.(p=0.1)

Discussion: Previous reports note duration of ictal activity of 139 minutes in one study, and mean 36 seizures in another. Our cohort exhibits dramatically reduced EEG seizure burden, likely due to improved perioperative oxygen delivery to the brain. Our patients did receive a significant dose of benzodiazepines; both patients who seized were SV patients receiving large doses of intra- and postoperative benzodiazepines.

References:
1. Circulation 1998;97:773
2. JTCVS 2005;130:1278