Table 4: Ventilation effectiveness according to blood gas analysis parameters in COPD and OHS.

Before NIV With NIV Diff. 95% CI of the difference
mean SE mean SE mean lower upper p
COPD
pH 7.36 0.06 7.45 0.04 -0.09 -0.11 -0.07 0
pCO2 8.7 1.5 5.8 0.8 2.83 2.34 3.29 0
pO2 8.0 1.8 10.2 1.4 -2.25 -2.94 -1.56 0
HCO3 32.4 6.0 30.2 3.7 2.24 0.67 3.80 0.006
BE 8.6 5.2 5.8 3.0 2.78 1.30 4.26 0
SO2 87.5 8.2 95.7 2.6 -8.2 -10.64 -5.75 0
6-MWT 206.8 110.4 267.0 108.4 60.2 81.7 38.8 0
OHS
pH 7.37 0.06 7.45 0.05 -0.08 -0.10 -0.06 0
pCO2 8.5 1.2 5.9 0.8 2.55 2.12 2.98 0
pO2 7.6 1.3 10.0 1.7 -2.37 -2.99 -1.75 0
HCO3 32.7 4.9 30.0 4.0 2.65 0.98 4.32 0.003
BE 8.5 4.1 5.1 2.7 3.43 2.02 4.84 0
SO2 86.7 5.4 95.1 2.6 -8.34 -10.40 -6.35 0
6-MWT 190.8 124.0 259.0 137.4 65 93.7 36.2 0

Blood gas analysis at rest, spontaneous breathing. Before NIV: Before initiation of ventilation; with NIV: before discharge with ventilation. Values as mean, standard deviation, and difference: before NIV – with NIV; 6-MWT walk distance: with NIV – before NIV. p: significance level, two-sided, (t-test for dependent samples).