Table 2

Physiological parameters, exercise capability and health-related quality of life: high-intensity versus low-intensity NPPV

	Period	LI-NPPV	HI-NPPV	Difference between treatments (95% CI)	p Value
Paco₂ (mm Hg) mean nighttime	Period 1	56.6±9.2	48.1±5.8	−9.2 (−13.7 to −4.6)	0.001
Paco₂ (mm Hg) mean nighttime	Period 2	57.2±7.7	47.3±9.3	−9.2 (−13.7 to −4.6)	0.001
HCO₃⁻ (mmol/l) mean nighttime	Period 1	31.3±2.2	28.9±1.9	−1.9 (−3.5 to −0.3)	0.022
HCO₃⁻ (mmol/l) mean nighttime	Period 2	31.1±2.1	29.6±2.6	−1.9 (−3.5 to −0.3)	0.022
TLC (l)	Period 1	7.5±1.6	7.6±1.5	0.03 (−0.52 to 0.57)	0.91
TLC (l)	Period 2	7.4±0.8	7.3±1.5	0.03 (−0.52 to 0.57)	0.91
FEV₁ (l)	Period 1	0.64±0.11	0.97±0.46	0.05 (−0.01 to 0.11)	0.086
FEV₁ (l)	Period 2	0.94±0.46	0.70±0.17	0.05 (−0.01 to 0.11)	0.086
VC (l)	Period 1	1.82±0.23	2.22±0.59	0.08 (−0.2 to 0.36)	0.55
VC (l)	Period 2	2.29±0.87	2.00±0.18	0.08 (−0.2 to 0.36)	0.55
6MWD (m)	Period 1	271±56	302±163	14 (−42 to 70)	0.58
6MWD (m)	Period 2	308±145	303±93	14 (−42 to 70)	0.58
BDS after 6MWT	Period 1	6.5±2.8	3.4±3.6	−2.4 (−4.3 to −0.4)	0.025
BDS after 6MWT	Period 2	6.6±4.5	5.0±2.9	−2.4 (−4.3 to −0.4)	0.025
Paco₂ (mm Hg) mean daytime	Period 1	51.8±8.6	50.1±3.0	−2.9 (−7.1 to 1.4)	0.17
Paco₂ (mm Hg) mean daytime	Period 2	53.5±8.6	49.6±6.7	−2.9 (−7.1 to 1.4)	0.17
HCO₃⁻ (mmol/l) mean daytime	Period 1	30.1±2.7	29.4±1.3	−1.0 (−2.5 to 0.5)	0.18
HCO₃⁻ (mmol/l) mean daytime	Period 2	30.5±2.3	29.3±2.3	−1.0 (−2.5 to 0.5)	0.18
PImax (kPa)	Period 1	5.0±1.2	6.4±3.0	0.01 (−0.65 to 0.66)	0.99
PImax (kPa)	Period 2	5.3±1.9	4.6±1.7	0.01 (−0.65 to 0.66)	0.99
SRI-SS	Period 1	60.3±12.9	65.3±21.2	−0.14 (−4.9 to 4.6)	0.95
SRI-SS	Period 2	65.3±23.1	60.1±1\0.3	−0.14 (−4.9 to 4.6)	0.95

Data are presented as mean±SD.
6MWD, 6-minute walking distance; 6MWT, 6-minute walking test; BDS, Borg dyspnoea scale; FEV₁, forced expiratory volume in 1 s; HI-NPPV, high-intensity non-invasive positive pressure ventilation; HCO₃⁻, bicarbonate; LI-NPPV, low-intensity non-invasive positive pressure ventilation; Paco₂, arterial carbon dioxide tension; PImax, maximal inspiratory mouth occlusion pressure; SRI-SS, Severe Respiratory Insufficiency Questionnaire Summary Score; TLC, total lung capacity; VC, vital capacity.