The Role of EEG Recordings in Children undergoing Cardiac Surgery for Congenital Heart Disease

Background: Neurological dysfunction may occur after corrective cardiac surgery using cardio-pulmonary bypass (CPB) with or without circulatory arrest. Different neurophysiological monitoring systems have been employed to detect neurological complications and possible brain injury in infants and children during and after cardiac surgery. The value of electroencephalogram (EEG) in infants and children at risk for neurological sequelae has not been systematically studied.

Methods: Sequential performance of two EEGs before and after cardiac surgery at a tertiary University Hospital to screen for possible brain injury after cardiac surgery in neonates and children undergoing CPB surgery. In addition, a complete neurological examination and assessment by a physiotherapist was performed.

Results: Over a 4-year period, in 313 patients (age: 54.2 ± 55.7 months; normal initial EEG) after cardiac surgery CPB (duration of surgery: 146.0 ± 58.9 min; aortic cross clamp time: 34.1 ± 19.1 min), a 19-channel EEG recording was performed 2.4 ± 1.8 days prior to and 11.6 ± 5.3 days after cardiac surgery. An abnormal EEG was detected in only 8 of 313 patients (2.5%; focal slowing: 1, generalized slowing: 5, epileptiform discharges: 2) after cardiac surgery, while the EEG was normal in the remaining 305 patients (97.5%). In 1 patient, an intra-cerebral pathology was seen on MRI (ischemic); in 5 patients, follow-up EEGs were performed, which revealed normalized findings. None of the 8 patients demonstrated new focal neurological deficits on physical examination, but 33 (9.7%) children demonstrated minor abnormalities (e.g., subtle motor asymmetry, increase in muscle tone, etc.), which were unrelated to abnormal EEG findings.

Conclusion: According to the used protocol, pathological EEG findings were very infrequent in our study cohort. The routine and indiscriminative recording of EEGs in children before and after corrective or palliative cardiac surgery for congenital heart disease using CPB is not recommended. Further intra-operative neuromonitoring methods with immediate intervention should be evaluated.