Extrinsic Threshold PEEP Reduces Post-exercise Dyspnea in COPD Patients: A Placebo-controlled, Double-blind Cross-over Study

Abstract

Purpose: Most patients with chronic obstructive pulmonary disease (COPD) complain of dyspnea during and following exercise, and the development of intrinsic positive end-expiratory pressure (PEEP) is thought to contribute to lung hyperinflation and dyspnea. Many people with COPD use pursed lip breathing (PLB) in an attempt to produce extrinsic PEEP to reduce lung hyperinflation and dyspnea during and following exertion. We hypothesized that the use of a threshold, extrinsic PEEP device would reduce post-exercise dyspnea in people with COPD.

Methods: A double blind, crossover study was conducted on post-exercise dyspnea in 8 patients with COPD whose exercise tolerance was limited by dyspnea. Subjects performed two identical 6-minute treadmill bouts that led to a Borg dyspnea rating of at least 5/10. Dyspnea, heart rate, and oxygen-hemoglobin saturation (SpO(2)) were recorded at rest, every 2 minutes during exercise and at 2, 5, and 10 minutes post-exercise. Immediately following the exercise bouts, the subjects used either a threshold PEEP device for 6 breaths at 10 cm H(2)O or a Sham device.

Results: Heart rate and SpO(2) were not different between treatments any time point before, during, or after exercise. Dyspnea ratings were not different between devices at rest or during exercise, but were lower in the post-exercise period following use of PEEP (p < 0.05). When asked which device, if any, the subjects would prefer to use to relieve post-exercise dyspnea, 7 of 8 chose the PEEP device and one had no preference.

Conclusions: We found that the use of a PEEP device can help reduce postexercise dyspnea in patients with COPD.

Keywords: COPD; PEEP; dyspnea; exertion; pursed lip breathing.

Figure 1

Heart rate response. HR was higher (p< 0.05) at minutes 2, 4 and 6 of exercise compared to rest and 2, 5 and 10 minutes post-exercise (Pex). Time intervals with the same letter designation are not different (p > 0.05). There were no significant differences between the PEEP and Sham treatments.

Figure 2

SpO₂(%) response. SpO₂(%) was lower (p< 0.05) at minutes 2,4 and 6 of exercise compared to rest and 2, 5 and 10 minutes post-exercise. Time intervals with the same letter designation are not different (p > 0.05). There were no significant differences between the PEEP and Sham treatments, p > 0.05. Data shown as mean ± SE.

Figure 3

Dyspnea ratings. Dyspnea ratings were lower following the use of PEEP (b) compared to the Sham condition (a) at 2, 5 and 10 minutes post-exercise, p < 0.001. Data shown as mean ± SE.