Sir.—In the March issue of AJDC, Ramsay et al1 reported that nine of 19 infants required ductus ligation because of initial treatment failure or relapse after indomethacin administration for a patent ductus arteriosus (PDA). Their treatment regimen with indomethacin consisted of an initial dose of 0.2 mg/kg followed by two doses of 0.1 mg/kg at 12- and 24-hour intervals. Ramsay et al speculated that the success rate of the treatment could be improved by increasing the amount of the first and/or subsequent indomethacin doses. We would like to report our experience with indomethacin given in three doses of 0.2 mg/kg every eight hours.
In our unit, PDA is suspected if an infant has consistent clinical signs or cannot be weaned from the ventilator and after the primary cause for administration of mechanical ventilation has resolved. The diagnosis is always confirmed with contrast echocardiography2 or echo-Doppler cardiography. The