Researchers Using EEG Find Seizures in Newborns After Cardiac Surgery

It is imperative for clinicians to detect and treat seizures that may occur in newborns with congenital heart disease (CHD) who have cardiac surgery. Seizures are associated with underlying brain injury, greater illness severity, and worse neurodevelopmental outcomes. The problem is that seizures can be difficult to identify during a routine bedside clinical assessment.

Continuous postoperative encephalographic (EEG) monitoring can show physicians when these medically fragile patients are experiencing a seizure by measuring the electrical activity in their brains. Yet, many centers do not follow professional guidelines issued in 2011 by The American Clinical Neurophysiology Society (ACNS) that call for continuous EEG monitoring of neonates undergoing surgery for CHD.

Experts at The Children’s Hospital of Philadelphia acted on the ACNS recommendations and began routine postoperative EEG monitoring for these patients in 2012. In a study published in the July issue of The Journal of Thoracic and Cardiovascular Surgery, CHOP cardiac critical care physicians and colleagues at the Perelman School of Medicine at the University of Pennsylvania reported results from implementation of the EEG monitoring clinical pathway.

“We found that continuous EEG monitoring identified newborns who had seizures, which indicated underlying brain injury, and are a risk factor for worse neurodevelopmental outcomes and mortality,” said study leader Maryam Y. Naim, MD, an attending physician in CHOP’s Pediatric Cardiac Intensive Care Unit. The majority of the seizures found using EEG would not have been visible to clinical caregivers, she added.

Over an 18-month period, the researchers studied 161 newborns with CHD who underwent open heart surgery at CHOP and received continuous EEG monitoring as part of routine postoperative monitoring. The study team found seizures in 13 of the infants (8 percent). Of those 13 infants, 11 (85 percent) had subclinical seizures, detectable only by EEG. Eight of the 13 infants had status epilepticus seizures, which are particularly dangerous. Five of the 13 infants with seizures died, which is a mortality rate of 38 percent, compared to four deaths among the 148 infants who did not have seizures (3 percent). “

Recognizing these seizures early is crucial for implementing treatments to prevent their recurrence,” Dr. Naim said, although she acknowledged that investigators have not yet demonstrated that treating seizures will improve long-term outcomes in high-risk pediatric heart patients.

An editorial commentary that accompanied the study calls for a larger, multicenter study to analyze continuous EEG monitoring following infant heart surgery and to investigate seizure prevention and treatment. The commenters also advocate for a less expensive and less labor-intensive screening tool than continuous EEG monitoring.

Funds from the National Institutes of Health and the June and Steve Wolfson Family Foundation supported this research.