Baseline | Final | Change | ANCOVA p-value NIMV versus s-NIMV | ||
Pa,CO2 mmHg | NIMV | 56.5±6 | 48.3±4 | −8.2 | <0.0001 |
s-NIMV | 56.7±6 | 56.0±7 | −0.7 | ||
Pa,O2 mmHg | NIMV | 45.3±5 | 53.0±6 | 7.7 | <0.001 |
s-NIMV | 47.9±5 | 50.1±5 | 2.2 | ||
HCO3− mEq·L−1 | NIMV | 34±3 | 29±2 | −5 | <0.0001 |
s-NIMV | 33±4 | 33±4 | 0 | ||
pH | NIMV | 7.39±0.3 | 7.39±0.2 | 0 | ns |
s-NIMV | 7.38±0.2 | 7.38±0.2 | 0 | ||
VT mL | NIMV | 526±158 | 693±196 | 167 | <0.0001 |
s-NIMV | 529±145 | 541±158 | 12 | ||
fR breaths·min−1 | NIMV | 21±5 | 17±5 | −4 | <0.0001 |
s-NIMV | 20±5 | 21±5 | 1 | ||
V′E L·min−1 | NIMV | 10.7±3 | 11.4±3 | 0.7 | ns |
s-NIMV | 10.4±3 | 11.1±3 | 0.7 | ||
FEV1 L | NIMV | 0.75±0.18 | 0.83±0.21 | 0.08 | <0.001 |
s-NIMV | 0.76±0.19 | 0.76±0.19 | 0.00 | ||
FVC L | NIMV | 2.32±0.7 | 2.55±0.8 | 0.23 | <0.001 |
s-NIMV | 2.26±0.7 | 2.24±0.7 | −0.02 | ||
FEV1/FVC % | NIMV | 34±9 | 34±10 | 0 | ns |
s-NIMV | 35±7 | 35±7 | 0 | ||
P0.1 cmH2O·L−1 | NIMV | 4.4±1.7 | 3.0±1.2 | −1.4 | <0.0001 |
s-NIMV | 4.2±1.3 | 4.3±1.3 | 0.1 | ||
P0.1/VT/tI cmH2O·L−1·s−1 | NIMV | 8.2±2.8 | 5.1±1.7 | −3.1 | <0.0001 |
s-NIMV | 7.9±3.0 | 7.8±2.7 | −0.1 | ||
PI,max cmH2O | NIMV | 53±13 | 61±14 | 8 | 0.034 |
s-NIMV | 58±12 | 62±12 | 4 | ||
TTmus | NIMV | 0.14±0.07 | 0.09±0.07 | −0.05 | <0.0001 |
s-NIMV | 0.11±0.03 | 0.11±0.04 | 0 | ||
6MWD m | NIMV | 329±103 | 405±95 | 76 | <0.0001 |
s-NIMV | 380±94 | 393±84 | 13 | ||
Borg scale points | NIMV | 6.6±1.7 | 5.1±1.7 | −1.5 | <0.0001 |
s-NIMV | 6.3±1.8 | 6.2±1.4 | −0.1 |
Data are expressed as mean±sd. ANCOVA: analysis of covariance; NIMV: noninvasive mechanical ventilation; s-NIMV: sham-NIMV; Pa,O2: arterial oxygen tension; Pa,CO2: carbon dioxide arterial tension; HCO3−: serum bicarbonate; VT: tidal volume; fR: breathing frequency; V′E: minute ventilation; FEV1: forced expiratory volume in one second; FVC: forced vital capacity; P0.1: mouth occlusion pressure; P0.1/VT/tI: effective respiratory impedance; PI,max: maximal inspiratory pressure; TTmus: tension-time index of inspiratory muscles; 6MWD: 6-min walking distance; ns: not significant.