Table 4

Changes in gas exchange, anthropometrics, spirometry, daytime somnolence and HRQL between NIV initiation and follow-up

AVAPSFixed-level PSMean difference between treatments (95% CI)p Value
∆PaCO2 (kPa)−0.6±1.0−0.6±1.10 (−0.7 to 0.6)0.867
∆PaO2 (kPa)0.2±1.70.5±1.60 (−1 to 1)0.519
∆HCO3 (mmol/litre)−3±3−3±40 (−2 to 2)0.825
∆BMI (kg/m2)−1±2−2±41 (−1 to 2)0.497
∆Fat free mass (kg)−1±60±8−1 (−4 to 3)0.805
∆Waist circumference (cm)−3±5−2±7−1 (−3 to 4)0.676
∆FEV1 (% predicted)6±134±142 (−6 to 10)0.588
∆FVC (% predicted)6±125±171 (−7 to 10)0.777
∆ESS (/24)−5±6−6±61 (−2 to 5)0.428
∆SRI-SS (/100)11±127±135 (−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).