# Diaphragmatic Ultrasound in Neonates with Transient Tachypnea: Comparison with Healthy Controls and Inter-Operator Reliability

## TL;DR

This study shows that diaphragmatic ultrasound can detect early functional issues in newborns with transient tachypnea, helping to assess disease severity and guide treatment.

## Contribution

The study introduces the use of diaphragmatic ultrasound in combination with lung ultrasound to monitor neonates with transient tachypnea.

## Key findings

- Diaphragmatic excursion increases in healthy neonates during the first 48 hours.
- TTN infants show lower diaphragmatic excursion compared to controls on day two.
- A negative correlation between diaphragmatic excursion and lung ultrasound score suggests impaired diaphragmatic function in TTN.

## Abstract

What are the main findings?
•Diaphragmatic excursion increases during the first 48 h in healthy neonates.•On day two, TTN infants show lower diaphragmatic excursion compared with controls, and a negative correlation develops between excursion and LUS, indicating impaired diaphragmatic function in the context of lung disease.

Diaphragmatic excursion increases during the first 48 h in healthy neonates.

On day two, TTN infants show lower diaphragmatic excursion compared with controls, and a negative correlation develops between excursion and LUS, indicating impaired diaphragmatic function in the context of lung disease.

What are the implications of the main findings?
•Diaphragmatic ultrasound may help identify early functional impairment in neonates with TTN, complementing lung ultrasound to characterize disease severity.•Integrated lung–diaphragm ultrasound assessment may support monitoring of disease progression and guide decisions on respiratory support, especially during the first 48 h of life.

Diaphragmatic ultrasound may help identify early functional impairment in neonates with TTN, complementing lung ultrasound to characterize disease severity.

Integrated lung–diaphragm ultrasound assessment may support monitoring of disease progression and guide decisions on respiratory support, especially during the first 48 h of life.

Background: The role of diaphragmatic function in transient tachypnea of the newborn (TTN) remains poorly understood. This study aimed to compare diaphragmatic ultrasound parameters between neonates with TTN requiring non-invasive ventilation (NIV) and healthy neonates. Secondary objectives include the relationships between these parameters and gestational age (GA), birth weight (BW), and the evaluation of inter-operator reproducibility. Methods: This prospective observational pilot study involved neonates with GA ≥ 34 weeks with clinical and ultrasound diagnosis of TTN treated with NIV. An equal number of healthy neonates served as controls. Diaphragmatic and lung ultrasound were performed on day 1 (T0) and day 2 (T1) of life. Measurements included end-inspiratory and end-expiratory diaphragmatic thickness (DTi and DTe, respectively), diaphragmatic excursion (DE), and Lung Ultrasound Score (LUS). Inter-operator reproducibility was tested in 31 neonates (62 scans in total). Results: Forty neonates were enrolled (20 TTN, 20 controls). DE was significantly higher in controls compared with TTN neonates (4.6 ± 0.9 mm vs. 5.4 ± 1.3 mm, p = 0.03) and increased from T0 to T1 in the control group (4.6 ± 1.1 mm vs. 5.4 ± 1.3 mm, p = 0.04), while no significant variation was observed in TTN cases. A negative correlation, approaching significance, was found between DE and LUS at T1 (p = 0.05). DTi and DTe increased linearly with GA and BW (p < 0.001). Bland–Altman analysis showed low bias and acceptable limits of agreement between measurements. Conclusions: The underlying pulmonary disease may influence diaphragmatic function in neonates with TTN. The integration of lung and diaphragmatic ultrasound could be useful for monitoring disease progression and follow-up.