Results 5 patients had PDA ligation within the study period. Average gestation at birth was 25+4 weeks and average birth weight was 0.754kg. Surgery was performed at an average weight of 1.027kg and 26.8 days. 9 PICC lines were inserted; mean of 1.8 per patient with removal following a mean of 12.5 days. 2 cases of catheter related thrombosis, post PDA ligation, resulted in SVC obstruction. Both patients had a PICC in situ at the time of surgery, the other 3 patients did not have PICC access during surgery. SVC thrombosis was detected at a mean of 15 days post operatively. One affected patient died subsequently due to complications. Conclusions Post-surgical catheter related thrombosis is well documented. SVC syndrome can infrequently result as a complication, which may cause severe respiratory compromise leading to high morbidity and mortality. As treatment of SVC syndrome is very difficult, especially in post operative patients and with a trend towards fewer PDA ligations, increased awareness in neonatal units may allow early diagnosis and thrombolytic therapy to prevent the progression of this syndrome.