The Role of Lung Ultrasound as an Early Diagnostic Tool for Need of Surfactant Therapy in Preterm Infants with Respiratory Distress Syndrome.

OBJECTIVE: This study aimed to determine the accuracy of neonatal lung ultrasound (LUS) in predicting the need for surfactant therapy compared with chest X-ray (CXR) in preterm infants.

STUDY DESIGN: A prospective double-blind study was conducted in infants with a gestational age <34 weeks with respiratory distress syndrome (RDS) by evaluation with LUS and CXR on admission.

RESULTS: Among 45 preterm infants, the median (interquartile range [IQR]) LUS score was 4 (2-8) in the mild RDS group, whereas it was 10 (IQR: 9-12) in the severe RDS group ( p  < 0.01). The LUS score showed a significant correlation with the need for total surfactant doses ( ρ  = 0.855; 95% confidence interval [CI]: 0.801-0.902; p  < 0.001). A cut-off LUS score of four predicted the need for surfactant with 96% sensitivity and 100% specificity (area under the curve [AUC]: 1.00; 95% CI: 0.97-1.00; p  < 0.01). LUS scores predicted continuous positive airway pressure (CPAP) failure accurately (AUC: 0.804; 95% CI: 0.673-0.935; p  = 0.001). A significant correlation was observed between LUS scores and positive end-expiratory pressure levels ( ρ  = 0.782; p  < 0.001). During the study period, the CXR number per infant with RDS decreased significantly when compared with preceding months ( p  < 0.001). The LUS score in the first day of life did not predict the development of bronchopulmonary dysplasia (AUC: 0.274; 95% CI: 0.053-0.495; p  = 0.065).

CONCLUSION: The LUS score in preterm infants accurately predicts the severity of RDS, the need for surfactant and CPAP failure. The routine use of LUS can decrease the frequency of CXRs in the neonatal intensive care units.

KEY POINTS: · LUS is a nonhazardous bedside technique.. · LUS predicts the need for surfactant in preterm infants.. · LUS predicts the severity of RDS better than CXR..