Changes in gas exchange, anthropometrics, spirometry, daytime somnolence and HRQL between NIV initiation and follow-up
| AVAPS | Fixed-level PS | Mean difference between treatments (95% CI) | p Value | |
| ∆PaCO2 (kPa) | −0.6±1.0 | −0.6±1.1 | 0 (−0.7 to 0.6) | 0.867 |
| ∆PaO2 (kPa) | 0.2±1.7 | 0.5±1.6 | 0 (−1 to 1) | 0.519 |
| ∆HCO3 (mmol/litre) | −3±3 | −3±4 | 0 (−2 to 2) | 0.825 |
| ∆BMI (kg/m2) | −1±2 | −2±4 | 1 (−1 to 2) | 0.497 |
| ∆Fat free mass (kg) | −1±6 | 0±8 | −1 (−4 to 3) | 0.805 |
| ∆Waist circumference (cm) | −3±5 | −2±7 | −1 (−3 to 4) | 0.676 |
| ∆FEV1 (% predicted) | 6±13 | 4±14 | 2 (−6 to 10) | 0.588 |
| ∆FVC (% predicted) | 6±12 | 5±17 | 1 (−7 to 10) | 0.777 |
| ∆ESS (/24) | −5±6 | −6±6 | 1 (−2 to 5) | 0.428 |
| ∆SRI-SS (/100) | 11±12 | 7±13 | 5 (−2 to 12) | 0.212 |
The p value refers to comparison between interventions by independent t test.
AVAPS, average-volume-assured pressure support; BMI, body mass index; ESS, Epworth Sleepiness Score (higher values indicate higher degrees of daytime somnolence); FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; HCO3, arterial concentration of bicarbonate; HRQL, health-related quality of life; PaCO2, arterial partial pressure of carbon dioxide; PaO2, arterial partial pressure of oxygen; PS, pressure support; SRI-SS, Severe Respiratory Insufficiency questionnaire summary score (higher values indicate better health-related quality of life).