Validity of foetal Doppler indices in predicting postnatal respiratory distress syndrome: a prospective study

Abstract

BackgroundRespiratory distress syndrome (RDS) is a potentially fatal condition of neonate occurring due to alveolar surfactant deficiency causing inefficient gaseous exchange and leading to hampered respiratory function. Purpose of our study is to investigate the role of Doppler indices in antenatal prediction of clinical Respiratory Distress Syndrome (RDS) in late preterm and early term foetuses using Main pulmonary artery (MPA) Doppler indices. The current study was conducted on 342 pregnant women between 34 and 39 weeks of gestational age, who came for routine third trimester ultrasound examination. The standard foetal biometric parameters, gestational age and estimated foetal weight were first obtained. The MPA Doppler indices like pulsatility index (PI), resistivity index (RI), peak systolic velocity (PSV), systolic/diastolic ratio and acceleration time/ejection time (At/Et) were recorded and correlated with the postnatal development of RDS.ResultsOf the 342 foetuses, neonatal RDS was diagnosed in 47 foetuses. Foetuses diagnosed with RDS had statistically higher PI and RI values, whereas At/Et ratio and PSV were lower. At/Et ratio, PI and RI, PSV showed significant correlation with gestational age and the most statistically significant correlation was found with At/Et ratio. A cut-off value of 0.2865 (sensitivity 89.45%, specificity 94.79%) and 0.3155 (sensitivity 93.22%, specificity 96.78%) correlated strongly with development of RDS in late preterm foetuses and early term infants.ConclusionFoetal MPA indices like PSV, RI, PI and especially Foetal At/Et ratio is a promising non-invasive tool which helps in identifying foetuses at risk and may be very useful to plan delivery in complicated pregnancies and also for better post-natal care of the neonate.