Diagnostic Utility of Bedside Lung Ultrasonography in Neonates with Respiratory Distress

Background: Lung Ultrasound (LUS) has recently become an important method for diagnostic examination and monitoring of lung disease. Many lung diseases, such as respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTNB), pneumonia were diagnosed by chest X-ray, but can now easily be diagnosed with LUS. LUS has many advantages over X-ray including accuracy, reliability, low cost, radiation free, simple investigation, do multiple times, results are obtained immediately. 
Objective: The aim of this study was to evaluate role of LUS in neonates with respiratory distress (RD) within 4 hours of life and to calculate the sensitivity, specificity, and negative and positive predictive value of LUS for RDS and TTNB, using an external reader blinded to the clinical condition. 
Design and Methods: Neonates born at a gestation from 28 weeks to 40 weeks born in the hospital and developing RD on first 4 hours of life were enrolled. The diagnosis based on clinico-radiological features as ascertained by the treating neonatologist was considered gold standard. Just before LUS, the RD was objectively scored using Modified Silverman Andersen score. X-ray and LUS were performed bed side within 4 hours of life. Images were captured and stored and interpreted by the Radiologist who was blinded to the neonate’s clinical condition. LUS were interpreted according to observational index included pleural A lines, B lines, Air bronchogram and Lung consolidation. Based on LUS findings, differentiation between RDS, TTNB, MAS and Pneumonia were made. 
Results: 100 neonates were studied. 22 infants had a final diagnosis of RDS and 64 of TTNB. LUS showed a Sn of 100% and Sp of 89.7%, with a PPV of 73.3% and a NPV of 100 % for RDS, and a Sn of 82.8% and Sp of 100% with a PPV of 100% and a NPV of 76.6% for TTNB. 
Conclusion: LUS is a reliable method to diagnose RDS and TTNB in newborns with RD with high sn and sp.