Question: Does a new positive expiratory pressure device (conical-PEP) decrease lung hyperinflation during exercise in patients with chronic obstructive pulmonary disease compared to normal breathing? Does it increase the duration of exercise? Thirteen patients with moderate to severe chronic obstructive pulmonary disease (mean FEV1 61% predicted) participated. The experimental intervention was conical-PEP breathing with a positive expiratory pressure of 4-20 cmH2O during 30% of 1 RM alternate knee extension exercise at 70% age-predicted HRmax to fatigue. The control intervention was normal breathing. Total lung capacity (inspiratory capacity and slow vital capacity), breathlessness, and leg discomfort were measured pre and post exercise. Cardiorespiratory function was measured pre and during the last 30 s of exercise. Duration of exercise was recorded. After the experimental intervention, inspiratory capacity increased 200 ml (95% CI 0 to 400) and slow vital capacity increased 200 ml (95% CI 0 to 400) more than the control intervention. Participants exercised for 107 s (95% CI -23 to 238) more during the experimental intervention than the control intervention. Conical-PEP breathing during exercise resulted in 6.1 fewer breaths/min (95% CI 1.4 to 10.8) than normal breathing; it did not have any adverse effects on CO2 retention or oxygen saturation.
The novel conical-PEP device decreases lung hyperinflation, is safe to use, and tends to increase the duration of exercise.