Lung Ultrasound to Diagnose Transient Tachypnea of the Newborn (TTN) Versus Respiratory Distress Syndrome (RDS) in Neonates

Respiratory distress is a common reason for admission to the neonatal intensive care unit (NICU) for both preterm and full term newborns. TTN and RDS are the two most common diagnoses associated with respiratory distress. Due to their similar clinical presentations, it is often difficult to differentiate the two diseases clinically. Currently chest radiography is used to differentiate between TTN and RDS, however, radiographic findings are not always definitively diagnostic.

In preliminary studies, lung ultrasonography has been shown to be a useful tool in diagnosing both TTN and RDS. However, no one has looked at the use of lung ultrasonography in differentiating TTN from RDS in the neonatal population. We propose to do so in this study.

Patients will be enrolled from neonatal admissions to the NICU with respiratory distress. Lung ultrasound will be performed on all enrolled subjects, looking for specific findings suggestive of either TTN or RDS. Data will be collected on gestational age, physical exam findings and level of respiratory support. Diagnoses will be recorded based on ultrasound findings. Accuracy of lung ultrasound diagnosis will be compared to that using radiographic chest radiography findings to evaluate if lung ultrasound is equivalent, or better than chest radiography in order to diagnose TTN versus RDS in this patient population.

Inclusion criteria

• gestational age ≥ 28 weeks
• symptoms of respiratory distress defined as:
• tachypnea (respiratory rate > 60 breaths per minute)
• FiO2 requirement >21%
• intercostal/subcostal retractions
• grunting and/or nasal flaring
• If clinically warranted, a chest x-ray will be done as part of the workup for respiratory distress; these patients with CXR will be included in the study.
• Inclusion criteria for the control group will be gestational age ≥ 28 weeks with no symptoms of respiratory distress (defined above).

Exclusion criteria

• neonates with prenatally diagnosed structural cardiac disease
• major multiple congenital anomalies
• other causes of respiratory distress that are not RDS or TTN (e.g. pneumothorax, CCAM or pneumonia).