Table 2 Comparison of general clinical characteristics and diaphragm ultrasound findings between the two groups

General clinical characteristics

 Gender (male, n,%)

19(86.3)

40(70.2)

2.200

0.138

 Age (years)

68(56,78)

68(54,77)

-0.103

0.918

 APACHE2 scores

21(15,25)

12(8,17)

-4.182

< 0.001

Oxygenation index(mmHg)

239.535 ± 94.084

305.508 ± 114.127

2.411

0.018

 SaO₂(%)

97 ± 3.232

98.08 ± 2.52

1.522

0.132

 Pplat (cmH₂O)

23.890 ± 1.197

20.350 ± 0.971

-13.093

< 0.001

 Vt (ml)

408.950 ± 19.118

456.170 ± 26.876

8.443

< 0.001

 F (time/min)

28(25,35)

20(18.22)

-6.106

< 0.001

 RSBI (bpm/L)

71.429(64.103,85.366)

44.315(40.523,48.837)

-6.350

< 0.001

 Cst, rs (ml/cmH₂O)

23.408 ± 1.560

30.094 ± 2.403

-6.176

< 0.001

 IWI (ml/cmH₂O/bpm/L)

37.613 ± 11.423

57.415 ± 17.773

5.846

< 0.001

Ultrasound indicators

 Dtei-1

0.348 ± 0.070

0.348 ± 0.069

3.236

0.002

 Dtei-2

0.346 ± 0.067

0.401 ± 0.070

3.439

0.002

 Dtee-1

0.274 ± 0.055

0.289 ± 0.047

1.135

0.308

 Dtee-2

0.277 ± 0.052

0.286 ± 0.045

0.766

0.446

 DTF-1

0.246 ± 0.026

0.385 ± 0.063

13.781

< 0.001

 DTF-2

0.23 ± 0.035

0.395 ± 0.068

0.766

< 0.001

 Average DTF

0.287 ± 0.081

0.350 ± 0.078

3.200

0.002