Abstract 1203 Poster Session IV, Tuesday, 5/4 (poster 326)

Pulmonary hemorrhage in infants with respiratory distress syndrome (RDS) may be related to the changes in pulmonary artery pressure(PAP). Decrease in aortopulmonary pressure gradient(ΔAPPG) - i.e. high PAP - on echocardiogram in preterm RDS has been reported to be associated with complications such as pulmonary hemorrhage. On the other hand, abrupt fall in PAP after surfactant administration increases left to right shunt through ductus and might be associated with pulmonary hemorrhage. We hypothesized that preterm RDS infants with high PAP would have delayed ductal closure and increased morbidities. We performed echocardiography on 36 preterm RDS infants with patent ductus arteriosus (PDA) (GA 29.5±2.5 wk, BW 1379±431 g) at postnatal day 2 and daily thereafter and divided them into two groups (high pressure group, HP, n=13, defined as ΔAPPG < 10mmHg and AT/RVET < 0.3; low pressure group, LP, n=23, ΔAPPG≥10mmHg and AT/RVET≥0.3). We compared parameters for PDA, respiratory status and incidence of complications. GA and Bwt were similar. Left atrial to aorta (LA/Ao) ratio, size of PDA before and after administration of in-domethacin were similar, but days of ductal closure was significantly longer in HP group than in LP group (11.4±2.8 vs. 5.6±2.4, p=0.03). Mean arterial pressure during first 72 hour was similar. Initial radiologic severity of RDS and Fi02 were comparable. In HP group after administration of surfactant, there was no improvement in radiologic severity (p=0.01), no decrease in Fi02 (p=0.02), and longer duration of mechanical ventilation (28±19 vs.8±5 days, p=0.021) compared to LP group. The incidence of pulmonary hemorrhage (7 vs. 0 cases, p=0.01) and death (8 vs. 0 cases, p=0.001) was greater in HP group than in LP group. In conclusion, high PAP in preterm infants with RDS and PDA was associated with delayed ductal closure, unimprovement of respiratory status after administration of surfactant and higher incidence of complications. We speculate that lowering PAP would be advisable to prevent complications like pulmonary hemorrhage.