Effects of practice change on outcomes of extremely preterm infants with patent ductus arteriosus

Aim: To determine whether a decrease in patent ductus arteriosus (PDA) treatment or ligation in extremely preterm (EP) infants was associated with changes in rates of mortality and/or morbidities. Methods: Observational study on EP infants admitted from 2008 to 2015. The small baby guidelines do not mandate ligation, however, in late 2010 the guidelines were amended based on new literature suggested that ligation may increase rates of morbidities. Results: There were 717 EP infants admitted during the study period. There were no significant changes in gestational age, birthweight or annual admissions during the study period. The annual rate of PDA medical treatment declined significantly (R = 0.83, p = 0.01), while the annual rate of PDA ligation declined substantially (R = 0.88, p = 0.004). The annual mortality rate also declined significantly (R = 0.81, p = 0.014). The annual rates of bronchopulmonary dysplasia (BPD), necrotising enterocolitis and intraventricular haemorrhage did not change significantly. Conclusion: In this cohort of EP patients, the rate of PDA ligation decreased substantially since 2010, with no apparent adverse effects on mortality or rates of BPD. These data are consistent with the concept that ligation does not improve outcomes in EP infants.