Table 1

Demographics

	NIV duration<14 days n=1470 (95.5%)	NIV duration≥14 days n=69 (4.5%)	P value
Age, years	69±14	72±14	0.08
Female/male	418/1052	18/51	0.79
Do-not-intubate order	121 (8.2%)	19 (27.5%)	<0.01
Diagnosis
AECOPD	848 (57.7%)	34 (49.3%)	0.17
Pneumonia	333 (22.7%)	24 (34.8%)	0.03
ARDS	45 (3.1%)	1 (1.4%)	0.72
Asthma	28 (1.9%)	0 (0%)	0.63
Heart failure	36 (2.4%)	0 (0%)	0.41
Pulmonary cancer	59 (4.0%)	7 (10.1%)	0.03
Others	121 (8.2%)	3 (4.3%)	0.36
Data collected at the beginning of NIV
APACHE II score	16±4	17±4	0.42
Heart rate, beats/min	112±23	117±26	0.14
Respiratory rate, breaths/min	30±7	30±6	0.91
Systolic blood pressure, mm Hg	137±26	134±23	0.36
Diastolic blood pressure, mm Hg	81±16	80±15	0.59
GCS	14.7±1.0	14.7±0.6	0.78
pH	7.36±0.11	7.40±0.11	0.01
PaCO₂, mm Hg	58±25	54±24	0.20
PaO₂/FiO₂	182±89	161±74	0.05
Data collected at day 1 of NIV*
Heart rate, beats/min	93±20	100±17	0.01
Respiratory rate, breaths/min	24±6	26±6	0.02
Systolic blood pressure, mm Hg	124±20	123±20	0.90
Diastolic blood pressure, mm Hg	71±12	72±12	0.79
GCS	14.8±1.0	14.9±0.3	0.34
pH	7.42±0.07	7.44±0.06	0.04
PaCO₂, mm Hg	50±17	48±16	0.30
PaO₂/FiO₂	231±87	203±82	0.01
Data collected at day 7 of NIV†
Heart rate, beats/min	88±19	94±20	0.01
Respiratory rate, breaths/min	24±5	24±5	0.44
Systolic blood pressure, mm Hg	127±21	127±18	0.94
Diastolic blood pressure, mm Hg	72±12	71±12	0.47
GCS	14.8±0.9	14.7±1.1	0.52
pH	7.42±0.06	7.44±0.06	0.09
PaCO₂, mm Hg	50±15	48±15	0.30
PaO₂/FiO₂	228±87	195±72	<0.01

*At day 1 of NIV, only 1158 patients were left in the study.
†At day 7 of NIV, only 343 patients were left in the study (9 patients were excluded because some data were unavailable).
AECOPD, acute exacerbation of chronic obstructive pulmonary disease; ARDS, acute respiratory distress syndrome; GCS, Glasgow Coma Scale; NIV, non-invasive ventilation.