Relationship between neonatal respiratory distress syndrome pulmonary ultrasonography and respiratory distress score, oxygenation index, and chest radiography grading

Table 1 Ultrasonography B-line and dual-lung 6-zone pulmonary consolidation score in children with respiratory distress syndrome

Classification	Ultrasonography changes	Ultrasonography scores
B-line	There are A-lines and the number of B-lines is < 3	0
	B-lines appear between two consecutive ribs or more, i.e. B-lines ≥ 3	1
	Dense and integrated B-line (without A-line)	2
Pulmonary consolidation	No pulmonary consolidation	0
	Involved intercostal space, lung consolidation range ≤ 1/2 of the lung field	3
	The range of the lung consolidation involving the intercostal space is greater than half of the lung field	4

Table 2 X-ray grading and imaging manifestations

X-ray grading	X-ray imaging manifestations
0	No image changes
I	The transparency of both lung fields is generally reduced, with evenly scattered small particles and reticular shadows visible
II	Except for the aggravation of grade I changes, bronchial inflation sign can be seen, extending to the middle and outer zones of the lung field
III	The lesion worsens, the transparency of the lung field decreases further, and the cardiac and diaphragmatic margins appear blurry
IV	The entire lung field appears as a white lung, with more pronounced bronchial inflation signs resembling bald branches

Table 3 Comparison of respiratory distress syndrome neonatal ultrasonography score, respiratory distress score, oxygenation index, and chest X-ray grade before treatment

Items		n	Ultrasonography score, points	Respiratory distress score, points	Oxygenation index	Chest X-ray grade
						0	I	II	III	IV
Sex	Male	50	26.68 ± 7.41	7.60 ± 1.32	7.99 ± 2.64	0	1	13	17	19
	Female	23	26.87 ± 7.35	7.83 ± 0.98	7.76 ± 1.59	0	1	7	5	10
t/Z			−0.102	−0.730	0.388	−0.057
P value			0.919	0.468	0.699	0.955
Pregnancy duration in wk	< 32	29	25.66 ± 7.83	7.69 ± 1.26	7.59 ± 2.76	0	2	7	10	10
	32–36	35	26.77 ± 6.95	7.57 ± 1.29	8.01 ± 2.17	0	0	11	11	13
	> 36	9	30.11 ± 6.86	8.00 ± 0.87	8.66 ± 1.40	0	0	2	1	6
F/H			1.277	0.436	0.744	2.073
P value			0.285	0.648	0.479	0.355
Weight in g	< 1500	21	26.29 ± 8.28	7.76 ± 1.22	7.87 ± 3.06	0	1	6	5	9
	1500–2500	38	26.29 ± 6.85	7.53 ± 1.22	7.56 ± 2.03	0	1	10	14	13
	> 2500	14	28.64 ± 7.39	7.93 ± 1.27	8.97 ± 1.70	0	0	4	3	7
F/H			0.576	0.625	1.901	0.494
P value			0.565	0.538	0.157	0.781
First ultrasonography time in h	< 1	15	29.20 ± 6.13	8.07 ± 0.80	9.02 ± 2.65	0	0	2	3	10
	1–1.5	39	25.23 ± 7.68	7.59 ± 1.33	7.68 ± 2.30	0	2	12	13	12
	> 1.5	19	27.89 ± 7.09	7.53 ± 1.26	7.55 ± 2.06	0	0	6	6	7
F/H			1.954	1.000	2.135	5.689
P value			0.149	0.373	0.126	0.058

Data are mean ± standard deviation or n (%).

Table 4 Comparison of the respiratory distress syndrome neonatal ultrasonography score, respiratory distress score, oxygenation index, and chest X-ray grade before and after treatment

Items		Before treatment, n = 73	After treatment, n = 73	t/Z	P value
Ultrasonography score (points)		26.74 ± 7.34	15.12 ± 6.11	17.324	< 0.001
Respiratory distress score (points)		7.67 ± 1.23	3.93 ± 1.25	47.887	< 0.001
Oxygenation index		7.92 ± 2.35	5.84 ± 2.13	9.543	< 0.001
Chest X-ray grade	0	0 (0.00)	32 (43.84)	−7.460	< 0.001
	I	2 (2.74)	24 (32.88)
	II	20 (27.40)	16 (21.92)
	III	22 (30.14)	1 (1.37)
	IV	29 (39.73)	0 (0.00)

Data are mean ± standard deviation or n (%).

Table 5 Correlation between the respiratory distress syndrome neonatal ultrasonography score and respiratory distress score, oxygenation index, and chest X-ray grade before and after treatment (n = 73)

Comparator	Ultrasonography score
	Before treatment		After treatment
	ρ	P value	ρ	P value
Respiratory distress score	0.446	< 0.001	0.429	< 0.001
Oxygenation index	0.703	< 0.001	0.748	< 0.001
Chest X-ray grade	0.859	< 0.001	0.764	< 0.001

Table 6 Respiratory distress syndrome parameters

Categorical variable	AUC	SE	P value	Youden index	Optimal cutoff value	Sensitivity, %	Specificity, %
I–II	1.000	0.000	< 0.001	1.000	> 12	100.00	100.00
II–III	0.805	0.077	< 0.001	0.682	> 24	68.18	100.00
III–IV	0.946	0.030	< 0.001	0.795	> 30	93.10	86.36

AUC: Area under the curve; SE: Standard error.