Sir.—In their recent report in AJDC, Ramsay et al1 found a 58% closure rate in 19 premature infants with respiratory distress syndrome (RDS) who underwent indomethacin therapy for a patent ductus arteriosus proved by two-dimensional and pulsed Doppler echocardiographic studies. Furthermore, they reported an eventual surgical ligation rate of 50%. They concluded that the low response rate observed might have resulted from relatively late (mean age of patients, 7 days) indomethacin treatment.
In our neonatal intensive care unit between November 1984 and November 1986, 100 premature infants with RDS and a patent ductus arteriosus proved by two-dimensional Doppler echocardiographic studies underwent medical therapy with indomethacin. We analyzed the total number of indomethacin courses (utilizing the intravenous preparation at standard recommended dosages). These 100 patients underwent a total of 116 indomethacin treatment courses. Our patients fell into two main groups by their response to indomethacin: patients weighing less than