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 (rScO₂) 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 rScO₂ 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, rScO₂, cFTOE and aEEG were monitored before, during and up to 24 h after surgery.

Results Before surgery, median (range) rScO₂ 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 rScO₂ during surgery (range 2–21%), accompanied by a decrease in aEEG amplitude. Twelve infants had rScO₂ values below 50% during surgery, with five being below 40%. Only at 24 h after surgery was rScO₂ 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.