Noninvasive ventilation during exercise reduces dynamic hyperinflation in severe COPD

Noninvasive ventilation during exercise reduced dynamic hyperinflation and increased cycle endurance in adults with severe COPD, researchers reported in Chest.

“Bilevel noninvasive ventilation during exercise may provide greater benefits to people with dynamic hyperinflation than does noninvasive ventilation with inspiratory pressure support alone or techniques that provide only positive expiratory pressure by combining the beneficial effects of positive inspiratory and expiratory pressures,” Clancy J. Dennis, BEng, with the faculty of medicine and health at the University of Sydney, and colleagues wrote. “However, the effect on dynamic hyperinflation of bilevel noninvasive ventilation during exercise is unknown.”

The randomized, crossover trial included 19 participants with COPD (mean age, 69 years; 57.8% men) and an FEV₁/FVC of less than 0.7, an FEV₁ of less than 50% predicted, resting hyperinflation with residual volume/total lung capacity of more than 110% predicted, no exacerbations in the past 4 weeks and dynamic hyperinflation during a peak incremental cycle test. All participants completed three constant work rate endurance cycle tests in a random order of no noninvasive ventilation, noninvasive ventilation with standardized expiratory positive airway pressure and noninvasive ventilation with titrated expiratory positive airway pressure during exercise.

The primary outcome was isotime inspiratory capacity and exercise endurance time. Isotime inspiratory capacity was greater in cycle tests of noninvasive ventilation with standardized expiratory positive airway pressure (mean difference, 0.19 L) and titrated expiratory positive airway pressure (mean difference, 0.22 L) compared with cycle tests with no noninvasive ventilation. Similarly, compared with cycle tests with no noninvasive ventilation, exercise endurance time was also greater in tests of noninvasive ventilation with standardized expiratory positive airway pressure (mean difference, 153 seconds) and titrated expiratory positive airway pressure (mean difference, 145 seconds).

Researchers observed no difference between cycle tests involving noninvasive ventilation with standardized expiratory positive airway pressure and noninvasive ventilation with titrated expiratory positive airway pressure.

According to researchers, inspiratory capacity improvement at isotime and at the end of exercise with noninvasive ventilation with titrated expiratory positive airway pressure exceeded 200 mL in 79% of participants compared with no noninvasive ventilation. These results were greater than the minimal clinically important difference for inspiratory capacity in an exercise endurance cycle test with bronchodilators, according to the researchers. In addition, the exercise endurance time increase of 152 seconds was greater than the minimal clinically important difference of 105 seconds for constant-load endurance cycle tests that are established in pharmacologic interventions and exercise training programs, the researchers wrote.

“Bilevel noninvasive ventilation with a standardized expiratory positive airway pressure of 5 cm H₂O may be a beneficial adjunct to exercise training in patients with severe COPD who have clinically significant resting hyperinflation and/or dynamic hyperinflation during exercise,” the researchers wrote.