Patent ductus arteriosus in infants <29 weeks gestation--outcomes and factors affecting closure.

OBJECTIVE To determine Patent ductus arteriosus (PDA) closure rates for extremely preterm infants in a tertiary care centre, factors affecting response to indomethacin and outcomes of these infants relative to their PDA status. SETTING Neonatal intensive care unit in tertiary-care children's hospital. DESIGN Retrospective medical record review. METHODS A retrospective chart review of all infants <29 weeks gestation between 1st Jan 2003 and 30th June 2006 was carried out. Multiple courses of standard intravenous indomethacin (dose: 0.2 mg/kg 12 hourly; 3 doses) followed by a tail course (0.1 mg/kg/day; 3 doses) were used to treat PDA depending on clinical and hemodynamic status. Data on demographic characteristics, PDA status, use of indomethacin, and outcome factors such as chronic lung disease and mortality were collected. RESULTS A total of 166 infants were identified in the study period, of which 15 were excluded. The median gestation was 27 weeks [IQR (25, 28)] and the mean (SD) birthweight was 950 (244) grams. The remaining infants (n=151) were divided into three groups. Group1 (n=47): no or non-significant PDA, Group 2 (n=91): significant PDA closed after indomethacin treatment (= 1 course) and Group 3 (n=13): significant PDA not responding to indomethacin. The closure rate of PDA with indomethacin treatment (group 2) was 87%. A low gestational age < 26 weeks (OR 5.6, 95% CI 1.6-19.9) and female sex (OR 5.8, 95% CI 1.5-22.8) was associated with poor response to indomethacin in our study population. CONCLUSIONS Multiple indomethacin courses using the standard dosing approach result in high PDA closure rates for infants < 29 weeks gestation.