Table 2—

Arterial blood gases, spirometry and lung volumes before and after 3 weeks of noninvasive mechanical ventilation (NIMV)

BaselineFinalMean (95% CI) change from baseline after NIMV
Pa,CO2 kPa
 s-NIMV7.36±0.677.25±0.80
 NIMV7.57±0.806.45±0.53−1.12 (−1.52–−0.73)
Pa,O2 kPa
 s-NIMV6.56±0.806.73±0.80
 NIMV6.02±0.937.17±1.06#1.14 (0.70–1.50)
VE L·min−1
 s-NIMV10.10±310.28±2
 NIMV10.86±412.01±3*1.16 (0.05–2.28)
VT, mL
 s-NIMV552±147543±133
 NIMV514±173694±193181 (110–252)
ttot s
 s-NIMV3.36±0.83.25±0.8
 NIMV2.95±0.83.62±1.1#0.67 (0.29–1.06)
FEV1 % pred
 s-NIMV37.6±1136.7±11
 NIMV31.7±935.8±11#4.1 (1.5–6.9)
FVC % pred
 s-NIMV80±2178±20
 NIMV71±1780±189 (5–13)
FEV1/FVC %
 s-NIMV37.9±938.3±9
 NIMV36.6±1037.1±120.5 (−1.7–2.8)
FEF25–75% L·s−1
 s-NIMV0.25±0.080.24±0.08
 NIMV0.20±0.080.25±0.09#0.05 (0.015–0.076)
TLC % pred
 s-NIMV133±24136±25
 NIMV127±24117±23−10 (−13–−7)
FRC % pred
 s-NIMV171±41175±42
 NIMV173±36148±35−25 (−31–−18)
RV % pred
 s-NIMV201±55209±51
 NIMV201±48165±49−36 (−45–−27)
  • CI: confidence interval

  • Pa,CO2: arterial carbon dioxide tension

  • s-NIMV: sham NIMV

  • Pa,O2: arterial oxygen tension

  • VE: minute ventilation

  • VT: tidal volume

  • ttot: total breathing cycle time

  • FEV1: forced expiratory volume in one second

  • % pred: % predicted

  • FVC: forced vital capacity

  • FEF25–75%: forced mid-expiratory flow

  • TLC: total lung capacity

  • FRC: functional residual capacity

  • RV: residual volume

  • Analysis of covariance: *: p<0.05

  • #: p<0.01

  • : p<0.001