Effect of Continuous Positive Airway Pressure on Respiratory Sensation in Patients with Chronic Obstructive Pulmonary Disease during Submaximal Exercise

Abstract

We wished to evaluate the role of dynamic hyperinflation and dynamic airway compression as potential sources of exertional dyspnea in patients with chronic obstructive pulmonary disease (COPD). The rationale was that if such factors contribute importantly, then the administration of continuous positive airway pressure (CPAP), which serves to unload the inspiratory muscles and attenuate dynamic compression on expiration, should improve respiratory sensation. Further partitioning of CPAP into its continuous positive inspiratory pressure (CPIP) and continuous positive expiratory pressure (CPEP) components permitted an assessment of the relative importance of the above factors with respect to respiratory sensation. CPAP, CPIP, and CPEP (4 to 5 cm H2O each) were administered intermittently (for intervals of 40 to 60 s on each occasion) in random order during steady-state submaximal exercise in five patients with COPD (average FEV1, 40% predicted) and in five normal healthy subjects. Changes in the sense of breathing effort during the various pressure applications were assessed by asking the subjects to point to a category scale of -5 to +5, where -5 indicated that breathing was markedly easier and +5 indicated that breathing was markedly harder. CPAP, when administered to the COPD group, resulted in a highly significant (p less than 0.005) reduction in the sense of breathing effort. By contrast, CPAP significantly increased the sense of breathing effort in the normal group (p less than 0.01). CPIP facilitated breathing in both the COPD group and the normal group (p less than 0.05 and p less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Expiratory Positive Airway Pressure on Dynamic Hyperinflation During Exercise in Patients With COPD

“…Previous studies that applied continuous positive airway pressure (CPAP) in COPD patients during exercise demonstrated improvement in exercise endurance 13 and reduction of inspiratory muscle effort 14 and dyspnea. [13][14][15] Therefore, this study aimed to evaluate the effects of EPAP delivered by a spring loaded resistor face mask on operational lung volumes during exercise in patients with moderate to severe COPD who overtly developed effort related DH.…”

The role of inspiratory muscle function and training in the genesis of dyspnoea in asthma and COPD

“…Treatments that reduce hyperinflation have been shown to reduce dyspnoea significantly, e.g., bronchodilators [9], lung volume reduction surgery [10], and continuous positive airway pressure (CPAP) [11]. Thus, there is clear evidence that dyspnoea can be alleviated by reducing the load placed upon the inspiratory muscles.…”

Pulmonary hyperinflation a clinical overview

“…Provided that modest pressures are used, CPAP produces no further increase in FRC [65]. Furthermore, in ambulant patients with stable COPD, CPAP of 4-5 cmH 2 O has been shown to reduce dyspnoea during exercise [66], and to increase exercise endurance time [67], again without producing greater dynamic hyperinflation.…”