Predictive value of diaphragm ultrasound for mechanical ventilation outcome in patients with acute exacerbation of chronic obstructive pulmonary disease

Table 1 Comparison of clinical data between two groups

Variable	Successful ventilation group, (n = 68)	Failed ventilation group, (n = 26)	t/χ2	P value
Male [n (%)]	35 (51.47)	16 (61.54)	0.768	0.381
Age (years)	64.74 ± 4.25	65.77 ± 4.48	1.040	0.301
BMI (kg/m2)	23.41 ± 2.12	23.62 ± 2.15	0.428	0.669
Complications [n (%)]
Hypertension	39 (57.35)	16 (61.54)	0.136	0.713
Asthma	26 (38.24)	12 (46.15)	0.490	0.484
Diabetes	22 (32.35)	11 (42.31)	0.818	0.366
Systolic pressure (mmHg)	109.85 ± 21.09	107.77 ± 13.19	0.469	0.640
Mean arterial pressure (mmHg)	91.98 ± 9.79	90.85 ± 10.43	0.496	0.621
Heart rate (times/min)	83.79 ± 12.37	88.92 ± 12.56	1.790	0.077
Oxygen saturation (%)	87.93 ± 4.01	88.73 ± 5.39	0.788	0.433
Respiratory rate (times/min)	21.85 ± 3.24	23.04 ± 3.36	1.569	0.120
Hospital stays (d)	8.89 ± 3.14	11.46 ± 4.34	3.172	0.002
Blood gas analysis results
pH	7.32 ± 0.16	7.21 ± 0.15	2.936	0.004
PaO2 (mmHg)	47.69 ± 5.41	46.69 ± 5.66	0.790	0.432
PaCO2 (mmHg)	62.21 ± 3.69	66.54 ± 3.02	5.334	< 0.001
PaO2/FiO2	98.35 ± 5.24	96.32 ± 5.16	1.687	0.095
Diaphragm ultrasound
DTF (%)	24.18 ± 3.02	19.12 ± 3.18	7.172	< 0.001
DE (mm)	21.02 ± 2.26	17.42 ± 2.14	7.010	< 0.001
TI (s)	1.14 ± 0.19	1.06 ± 0.14	1.920	0.058
E-T index	2.39 ± 0.47	1.84 ± 0.33	5.411	< 0.001

pH: Potential of hydrogen; PaO2: Partial pressure of oxygen; PaCO2: Partial pressure of carbon dioxide; PaO2/FiO2: Oxygenation index; DTF: Diaphragm thickening fraction; DE: Diaphragm activity; E-T: Diaphragm movement time; TI: Time of inspiration.

Table 2 Multivariate logistic regression analysis of predictive indicators for non-invasive ventilation outcome in acute exacerbation of chronic obstructive pulmonary disease patients

Index	β	SE	Wald	P value	OR	95%CI
Hospital stays	0.221	0.156	1.999	0.157	1.247	0.918-1.694
pH	5.367	2.731	3.861	0.049	0.005	0.000-0.986
PaCO2	0.845	0.350	5.841	0.016	0.430	0.216-0.852
DTF	0.562	0.219	6.613	0.010	0.570	0.371-0.875
DE	0.190	0.219	0.758	0.384	1.210	0.788-1.857
E-T index	2.401	2.020	1.413	0.234	0.091	0.002-4.747

OR: Odds ratio; CI: Confidence interval; pH: Potential of hydrogen; PaCO2: Partial pressure of carbon dioxide; DTF: Diaphragm thickening fraction; DE: Diaphragm activity; E-T: Diaphragm movement time.

Table 3 Predictive efficacy of potential of hydrogen, partial pressure of carbon dioxide, and diaphragm thickening fraction for non-invasive ventilation outcomes in patients with acute exacerbation of chronic obstructive pulmonary disease

Index	AUC	95%CI	P value	Sensitivity	Specificity
pH	0.690	0.576-0.804	0.005	0.885	0.500
PaCO2	0.833	0.745-0.920	< 0.001	0.923	0.691
DTF	0.873	0.793-0.953	< 0.001	0.808	0.809

pH: Potential of hydrogen; PaCO2: Partial pressure of carbon dioxide; DTF: Diaphragm thickening fraction; AUC: Area under curve; CI: Confidence interval.