Central Nervous System Consequences in Infants of Cardiac Surgery Using Deep Hypothermia and Circulatory Arrest

Preoperative and postoperative neurological evaluation of 22 infants (4 days to 24 months old, 2.7 to 9.7 kg) having correction of congenital cardiac anomalies by deep hypothermia (14° to 23°C) and circulatory arrest (10 to 57 minutes) revealed only 6 normal clinical neurological examinations prior to surgery. Sixteen patients had neurological defects, delayed psychomotor development, or muscular hypotonia. Seizures occurred in 2 and choreo-athetosis in 4 of 22 survivors 4 to 6 days after surgery and varied in severity and duration. Abnormal electroencephalograms )eeg) 1 week after surgery in 6 patients did not necessarily correlate with clinical defects. Continuous EEG during 14 operations showed decreased voltage and frequency with hypothermia, but cerebral activity was not lost prior to circulatory arrest. Low-voltage (1 to 4μv) activity persisted in 8 patients through the arrest period.

Examination 2 to 15 months postoperatively showed that only 1 of 18 patients had significant persistent dyskinesias, and the EEG was normal in all except 3. Developmental delay and/or hypotonia persisted in one-half the patients, but the degree was often less marked.

Cerebral metabolism is altered by deep hypothermia and circulatory arrest, and neurological defects may follow. Fortunately, significant persistent neurological damage is unusual (1/22 = 4%).