Effects of Non-Invasive Ventilation Combined with Oxygen Supplementation on Exercise Performance in COPD Patients with Static Lung Hyperinflation and Exercise-Induced Oxygen Desaturation: A Single Blind, Randomized Cross-Over Trial

The effects of non-invasive ventilation (NIV) in addition to supplemental oxygen on exercise performance in patients with chronic obstructive pulmonary disease (COPD) with hyperinflation and exercise-induced desaturation (EID) remain unclear. We hypothesized that these patients would benefit from NIV and that this effect would be an add-on to oxygen therapy. Thirteen COPD patients with a residual volume >150% of predicted, normal resting arterial oxygen pressure (PaO2) and carbon-dioxide pressure (PaCO2) and EID during a six-minute walk test were included. Patients performed four constant work-rate treadmill tests, each consisting of two exercise bouts with a recovery period in between, wearing an oronasal mask connected to a ventilator and oxygen supply. The ventilator was set to the following settings in fixed order with clockwise rotation: Sham (continuous positive airway pressure (CPAP) 2 cm H2O, FiO(2) 21%), oxygen (CPAP 2 cm H2O, FiO(2) 35%), NIV and oxygen (inspiratory positive airway pressure (IPAP) 14 cm H2O/expiratory positive airway pressure (EPAP) 6 cm H2O, inspired oxygen fraction (FiO(2)) 35%), intermittent (walking: Sham setting, recovery: NIV and oxygen setting). During the first exercise, bout patients walked further with the oxygen setting compared to the sham setting (225 +/- 107 vs 120 +/- 50 meters, p <0.05), but even further with the oxygen/NIV setting (283 +/- 128 meters; p <0.05). Recovery time between two exercise bouts was shortest with NIV and oxygen. COPD patients with severe static hyperinflation and EID benefit significantly from NIV in addition to oxygen during exercise and recovery.