Baseline characters of participants
The baseline characteristics of the participants are summarized in Table
1. Throughout the study (Figure 1B), 322 infants developed symptoms or
signs of respiratory distress in the monitoring room. All of them
underwent LUS, and clinical data were collected. Twelve of these infants
were excluded according to the stated criteria (4 with complex
malformation or congenital lung diseases, 3 were transferred to another
hospital, and 5 did not have qualified LUS images). A total of 310
infants were enrolled, and their LUS images were obtained at one of
following times—-(67, 85, 92, 37, 29 infants with LUS obtained
at at 0.5 h, 1 h, 2 h, 4 h, 6 h after birth, respectively). After the
three-day follow-up, 236 infants were confirmed to be healthy, and 74
were admitted to the NICU due to pulmonary issues, including RDS
(28/74), TTN (31/74), pneumonia (6/74) and MAS (6/74). The GA range was
34w+0d to 41w+5d, and the birth weight range was 1990 g to 4520 g. Most
NICU and healthy infants were scanned at second 2 hour after birth.
Infants admitted to the NICU were more likely to have a higher
respiratory rate (65 (87.8%) vs 57 (24.2%), p<0.01) and a
higher incidence of lower TcSO2 (below 95% for more than 3 mins, 23
(31.1%) vs 18 (7.6%), p<0.01) than the healthy infants.