Abstract
The long-term effect of average volume-assured pressure support (AVAPS) on health-related quality of life (HRQOL) in chronic obstructive pulmonary disease (COPD) patients with chronic hypercapnic respiratory failure (CHRF) remains unclear. The objective of this study is to identify the long-term effect of AVAPS in COPD patients with CHRF through assessment of HRQOL, exercise tolerance after six months duration. METHODS: In this randomized, controlled, parallel-group study, 40 stable hypercapnic COPD patients were randomized in a 1:1 ratio to receive either spontaneous timed AVAPS (ST/AVAPS) (intervention) or Bilevel positive airway pressure (ST/BiPAP) (control). HRQL was measured with the Short Form 12 Health Survey Questionnaire (SF-12). Exercise tolerance assessed by 6 min walking distance. Analyses were done between groups from baseline to the average of six months measurements. RESULTS: AVAPS led to significant 6 months improvements in several domains of (SF-12) compared to the control group, with the greatest improvement seen in general health [treatment effect of 8.2 points (95% confidence interval [95% CI 3.2 to 11.7; p = 0.001)], vitality (treatment effect 5.4 points [95% CI 1.4 to 9.3]; p = 0.001), physical functioning 5.5 points [95% CI 1.1 to 9.8]; p = 0.001) and bodily pain 5.1 points [95% CI 3.4 to 8.8]; p = 0.002). The physical health summary score improved by 3.7 points (95% CI 1.2 to 5.8; p = 0.001), but no significant improvement in the emotional or social role functioning, mental health subscale was noted. AVAPS also resulted in improvement 6 min walking distance 9.2 points (95% CI - 1 to - 15];p = 0.001). A significant reduction in the daytime (PaCO2) was observed after 6 months in those treated with AVAPS. CONCLUSIONS: In COPD patients with hypercapnic respiratory failure, AVAPS improved exercise tolerance and multiple domains of HRQOL over six months of follow-up, with the significant improvement observed in general health.