Randomised placebo-controlled trial of non-invasive ventilation for hypercapnia in cystic fibrosis

Abstract

Background: The clinical benefits of domiciliary non-invasive positive pressure ventilation (NIV) have not been established in cystic fibrosis (CF). We studied the effects of nocturnal NIV on quality of life (QoL), functional and physiological outcomes in CF subjects with awake hypercapnia (PaCO2> 45 mmHg).

Methods: In a randomised, placebo-controlled, crossover study eight CF subjects with mean (SD) age 37 (8) years, BMI 21.1 (2.6) kg/m2, FEV1 35 (8) % predicted and PaCO2 52 (4) mmHg received six weeks of nocturnal (1) air (placebo), (2) oxygen and (3) NIV. The primary outcome measures were CF-specific QoL, daytime sleepiness and exertional dyspnoea. Secondary outcome measures were awake and asleep gas exchange, sleep architecture, lung function and peak exercise capacity.

Results: Compared to air, NIV improved the chest symptom score in the CFQoL Questionnaire (mean difference, 10; 95% CI, 5 to 16; p=0.002) and the transitional dyspnoea index score (mean difference, 3.1; 95% CI, 1.2-5.0; p=0.01). It reduced maximum nocturnal PtcCO2 (mean difference, -17mmHg; 95%CI, -7 to -28 mmHg; p=0.005) and increased exercise performance on the Modified shuttle test (mean difference, 83m; 95% CI, 21 to 144m; p=0.02). NIV did not improve sleep architecture, lung function or awake PaCO2.

Conclusion: Six weeks of nocturnal NIV improves chest symptoms, exertional dyspnoea, nocturnal hypoventilation and peak exercise capacity in stable adult CF patients with awake hypercapnia. Further studies are required to determine whether or not NIV can improve survival.