Ductal shunting, high pulmonary blood flow, and pulmonary hemorrhage

Objective: To describe the relationship among ductal shunting, estimated pu lmonary blood flow, and pulmonary hemorrhage in very preterm infants. Study design: A total of 126 babies born before 30 weeks' gestation (median gestation 27 weeks, range 23 to 29 weeks) underwent echocardiography, at 5 , 12, 24, and 48 hours of age; measurements included right and left ventric ular output, superior vena cava flow, and color Doppler diameter of any duc tal shunt. Pulmonary, blood now was derived from the sum of right ventricul ar output and estimated ductal shunt flow. Results: Twelve (9.5%) babies had a pulmonary hemorrhage at a mean age of 3 8 hours. Compared with the rest of the cohort, these 12 babies were less li kely to have had antenatal steroids (59% vs 90%) and were less mature (26 w eeks vs 27 weeks). At the echocardiogram closest to the pulmonary hemorrhag e, 11 (92%) of the 12 babies had a significant patent ductus arteriosus >1. 6 mm in diameter (median 2 mm, range 0.7 to 2.4 mm), and the median pulmona ry blood flow was 326 mL/kg/min (range 210 to 598 mL/kg/min). These measure ments were significantly higher than those found in the rest of the cohort in the same period (med;an duct diameter 0.5 mm [range 0 to 2.9 mm], median pulmonary blood now 237 mL/kg/min [range 107 to 569 mL/kg/min]). At 5-hour echocardiography the babies with pulmonary hemorrhage had significantly la rger diameter ducts but similar pulmonary blood flow. Conclusions: Pulmonary hemorrhage in preterm babies is associated with sign ificant ductal shunting and high estimated pulmonary blood flow.