Lung ultrasound
We performed beside LU at birth, at three days, and weekly thereafter
until 36 weeks’ PMA, and we calculated LU score as previously described
in neonatal patients 7 by adding the score (0-3)
obtained in three areas of the thorax defined by the anterior axillary
line, the posterior axillary line and the mammary line (upper anterior,
lower anterior and lateral), with a total range of 0 to 18.
We used a portable ultrasound machine (Sonoscape Medical Corp.,
Shenzhen, China) with a high-frequency linear 8-15 MHz probe, holding
the probe perpendicular to the ribs. All LU were performed by the same
neonatologist, and were recorded anonymously.