Early screening and treatment of "silent" patent ductus arteriosus in prematures with RDS

From January 1987 to December 1989, prematures with RDS weighing 1750 g or less admitted to the Neonatal Intensive Care Unite (NICU) were submitted from the third postnatal day to serial two-dimensional and pulsed Doppler (ATL MK 600) echocardiographic evaluation for "silent" patent ductus arteriosus (PDA). PDA was diagnosed in 36/175 prematures with RDS (20.5%). Thirty patients had indomethacin treatment and the PDA closed completely in 27 (90%); five needed a second course of indomethacin, that was effective in two (40%). Four RDS patients (4/36-11%) already weaned from the respirator, needed supplemental oxygen. The three non-responders and six other prematures with counterindications to the drug underwent surgical ligation (25%). As historical control, we retrospectively evaluated the population of preterm infants with RDS weighing less than or equal to 1750 g treated for hemodynamically significant PDA during three previous years before the screening protocol; in this group the echocardiographic and Doppler evaluations were done when congestive heart failure and pulmonary edema were clinically evident. In comparison, we found a reduced incidence of prematures with RDS treated for PDA, 7/120 (5.8%) a higher age at medical treatment (9 +/- 1.4 vs 4.4 - 2.3 days) and a larger prevalence of patients underwent ductal ligation (71.4%). These data show that early screening and treatment of "silent" PDA may result advantageous to improve the efficacy (90%) of indomethacin, in a critical time for the recovery of RDS, and furthermore decreasing the need of surgical ligation.