Aim: To evaluate the accuracy of lung ultrasound in diagnosing and differentiating transient tachypnea of the newborn and respiratory distress syndrome in preterm neonates. Material and methods: This was a single-center study. From January 2020 to June 2021. A total of 100 preterm neonates, admitted to the neonatal intensive care unit with symptoms of respiratory distress within six hours of birth, including 50 diagnosed with transient tachypnea of the newborn and 50 with respiratory distress syndrome on the basis of clinical examination, laboratory testing, chest X-rays, were recruited in the study. Lung ultrasound was performed in each neonate by a senior radiologist who was blinded to the clinical diagnosis. Lung ultrasound findings in both conditions were analyzed and compared. Results: Pulmonary edema manifesting as alveolar-interstitial syndrome, double lung point sign and less commonly as white out lungs in the absence of consolidation has 100% sensitivity and specificity in diagnosing transient tachypnea of the newborn. A combination of three signs of consolidation with air or fluid bronchograms, white out lungs and absent spared areas has 100% sensitivity and specificity for diagnosing respiratory distress syndrome. Double lung point sign was seen only in infants suffering from transient tachypnea of the newborn and consolidation with air or fluid bronchograms only in cases of respiratory distress syndrome. Conclusion: Lung ultrasound can accurately diagnose and reliably differentiate transient tachypnea of the newborn and respiratory distress syndrome in preterm neonates. It has advantages that cannot be replicated by chest radiography. Lung ultrasound may be used as an initial screening tool.

respiratory distress syndrome (RDS); transient tachypnea of the newborn (TTN); lung ultrasonography (LUS); neonatal intensive care unit (NICU)