SERIAL ASSESSMENT OF DUCTUS-ARTERIOSUS HEMODYNAMICS IN HYALINE-MEMBRANE DISEASE

Objectives. To assess the efficacy of Doppler echocardiography (DE) in the quantification of patent ductus arteriosus (PDA) shunt volume and to correlate PDA shunt volume with clinical outcome in infants with h yaline membrane disease.Methods. Ninety-eight DE studies were performe d in 30 preterm ventilated infants with hyaline membrane disease withi n the first 24 hours of age and then at 48-hour intervals to a maximum of three studies while ventilated with a final study after extubation . Right and left ventricular outputs (Q(RV) and Q(LV), respectively) a nd PDA flow were calculated using cross-sectional area and flow veloci ty integrals. Left atrial-to-aortic root diameter measurements were al so taken. Clinical outcomes were correlated with the shunt fraction (Q (LV)/Q(RV)). Results. Q(LV)/Q(RV) demonstrated a linear relationship w ith the left atrial-to-aortic root diameter ratio (n = 92; r = .79). I n the absence of a PDA (n = 33 studies), Q(RV) versus Q(LV) demonstrat ed a linear relationship (r = .88). In the presence of a PDA (n = 64 s tudies) the mean Q(LV) (334 +/- 133 ml/kg per minute) was significantl y greater than the mean Q(RV) (237 +/- 84 ml/kg per minute). There was a linear relationship between Q(LV) - Q(RV) (PDA Shunt volume) and PD A flow (n = 60; r = .84). In studies with exclusive left-to-right shun ting at the PDA (n = 48), the mean Q(LV) - Q(RV) (112 +/- 83 ml/kg per minute) was significantly higher than in those with bidirectional shu nting (n = 16; mean Q(LV) - Q(RV) 50 +/- 27 ml/kg per minute). Two inf ants with severe intraventricular hemorrhage (IVH grade 3) and two inf ants with periventricular leukomalacia (PVL) had significantly higher Q(LV)/Q(RV) (2.09 +/- 0.36 and 1.67 +/- 0.02 respectively) than those with no IVH (n = 6; Q(LV)/Q(RV) = 1.31 +/- 0.18) or those with IVH gra des 1 and 2 (n = 8; Q(LV)/Q(RV) = 1.48 +/- 0.27). There was no differe nce in Q(LV)/Q(RV) in infants with or without bronchopulmonary dysplas ia and retinopathy of prematurity. Necrotizing enterocolitis did not d evelop in any of the 30 infants. Conclusion. PDA shunt volume can be q uantified by DE. Larger studies are needed to correlate clinical outco me with Q(LV)/Q(RV).