[Incidence of clinically apparent ductus arteriosus in premature infants less than 2 000 g].

We have studied the incidence of patent ductus arteriosus (PDA), its clinical features and hemodynamic significance in 715 newborns < 2,000 g admitted to our nursery between 1978-1988. Among 566 in borns, 100 (18%) met clinical diagnostic criteria for PDA. Incidence of PDA by birth weight (BW) was: 17/88 (20%) for BW < 1,000 g; 57/179 (32%) for BW 1,000-1,499 g; and 26/299 (9%) for BW 1,500-1,999 g. PDA was considered hemodynamically significant (HS PDA) in 57 of the 100 babies with PDA, this was found to happen more frequently in smaller babies: 17/17 (100%) with BW < 1,000 g; 30/57 (52.6%) when BW was 1,000-1,499 g; and 10/26 (38.5%) for BW 1,500-1,999 g. Both incidence of PDA and percentage of HS PDA were significantly higher in preterms < 1,500 g (p < 0.01 and < 0.001 respectively). Among 149 outborns, 45 (30%) had PDA, the incidence by birth weight was: 7/17 (41%) in < 1,000 g; 27/70 (39%) in 1,000-1,499 g; and 11/62 (18%) for 1,500-1,999 g. The clinical findings and conditions more frequently found associated with HS PDA were: tachycardia (72%), bounding pulses (67%) and need of ventilatory support (64%), and 89% of these patients had some evidence of pulmonary disease, usually hyaline membrane disease (60%).