Echocardiographic Right Ventricular Pressure Ratio Correlates with Prolonged Oxygen Therapy in Patients with Moderate to Severe Bronchopulmonary Dysplasia - Abstract
Objective : To characterize the incidence of pulmonary hypertension in a cohort of patients with bronchopulmonary dysplasia [BPD] and to correlate echocardiographic markers of pulmonary artery pressure [PAP] with prolonged oxygen supplementation, blood oxygen saturation [SpO2], pH and pCO2. Study design: We prospectively studied 29 infants admitted to a level 3 Neonatal Intensive Care unit[NICU] between February 2006 and August 2007. Neonates born at less than 28 weeks of gestation and requiring oxygen supplementation at 34-36 weeks of postmenstrual age were included. Echocardiographic estimation of pulmonary arterial pressure [PAP] was done with interventricle septal motion, tricuspid regurgitation jet velocity, right ventricular pre-ejection period/ejection time ratio [RVPEP/RVET] and right ventricular acceleration time/ejection time ratio [RVAT/RVET] at weeks 0, 1, 4 and 6 of study. These
echocardiographic measurements were assessed for correlation with duration of oxygen therapy, SpO2
, pH and pCO2.
Results: Twenty-nine patients were enrolled at a mean postmenstrual age of 35 weeks and 3 days [±6 days [SD]]. BPD was moderate in 62% and severe in 38%. Twenty-four patients required prolonged oxygen therapy [oxygen needed past 44 weeks postmenstrual age]. RVPEP/RVET ratio was 0.21 in these patients compared to 0.13 [p=0.02] in those that did not require prolonged oxygen therapy. RVPEP/RVET ratio correlated with low pH [p=0.02] and high pCO2 [p=0.04]. It did not correlate with SpO2 levels. Conclusion: In infants with BPD, the RVPEP/RVET ratio at 34-42 weeks of postmenstrual age was higher in infants requiring prolonged oxygen therapy, and correlated with pH and pCO2. This RVPEP/RVET ratio could help with early identification of patients that will require prolonged oxygen therapy.