Electrical seizures are common during the peri-operative period in young infants undergoing surgery for congenital heart disease

  • Dr Julia Gunn, Murdoch Childrens Research Institute, Melbourne, Australia
  • Dr Rod Hunt, The Royal Children's Hopsital, Australia
  • Dr John Beca, Starship Children's Hospital, Auckland, New Zealand
  • Dr Terrie Inder, Washinton University, St Louis, United States
  • Dr Lara Shekerdemian, The Royal Children's Hopsital, Melbourne, Australia

    • Objective: To determine the incidence of peri-operative seizures in young infants undergoing cardiopulmonary bypass (CPB).
    Methods: 61 full-term infants undergoing surgery for CHD were enrolled in a prospective study of brain injury. Two-channel amplitude integrated EEG (aEEG) monitoring was undertaken prior to and during induction of anaesthesia, throughout surgery and for up to 72 hours post-operatively, with a further recording one week later. A blinded assessor reviewed the aEEG recordings for seizure activity on the background and raw traces. Chi2analysis was used to compare groups.
    Results: Median age at surgery was 6 days (IQR 2-55). Surgical procedures were as follows: Norwood/ Damus operations (24), systemic-to-pulmonary artery shunt (6), arterial switch operations (18), common arterial trunk repairs (5), complex aortic arch repairs (6) and miscellaneous (2). 22 (35%) infants had peri-operative electrical seizures. Only 1 had a clinical correlate. They were pre-operative in 2 (4%), intra-operative in 11 (20%) and during the post-operative phase in 13 (22%). Intra-operative seizures occurred under anaesthetic prior to CPB (3), during CPB (6), during rewarming (5) and following CPB (3). The aEEG background activity was less likely to normalise within 24 hours in those infants who experienced seizures (p=0.02). Severely abnormal background aEEG activity in the first 6 hours after CPB was strongly associated with post-operative seizures (p<0.0001).
    Conclusions: Sub-clinical electrical seizures are common in infants undergoing CPB, both during and after surgery. Further follow up of the survivors is essential to determine the long-term significance of these findings.