Is cerebral oxygen supply compromised in preterm infants undergoing surgical closure for patent ductus arteriosus?

BACKGROUND: A haemodynamically important patent ductus arteriosus (PDA) is a risk factor for brain damage in preterm infants. The authors previously reported lower regional cerebral oxygen saturation (rScO(2)) in infants with PDA, which recovered after administration of indomethacin. However, PDA ligation has been reported to pose an even higher risk of neurodevelopmental impairment.

OBJECTIVE: To investigate the impact of surgical closure of PDA on rScO(2) and cerebral fractional tissue oxygen extraction (cFTOE), measured by near-infrared spectroscopy, and on amplitude-integrated electro-encephalography (aEEG) measured brain activity.

DESIGN/METHODS: In 20 preterm infants (gestational age 24.7-30.4 weeks; birth weight 630-1540 g), blood pressure, arterial saturation, rScO(2), cFTOE and aEEG were monitored before, during and up to 24 h after surgery.

RESULTS: Before surgery, median (range) rScO(2) was 53% (41-68%), and during surgery, but before ductal clipping, it was 46% (31-89%). Eleven infants showed a drop in blood pressure and 13 infants a drop in rScO(2) during surgery (range 2-21%), accompanied by a decrease in aEEG amplitude. Twelve infants had rScO(2) values below 50% during surgery, with five being below 40%. Only at 24 h after surgery was rScO(2) higher (61% (36-85%), p<0.05) and cFTOE values lower (0.38 (0.09-0.61); p<0.05) compared with preclipping values.

CONCLUSION: Ductal ligation poses a risk for a further decrease in already compromised cerebral oxygenation in preterm infants.