Skip to main content
Log in

Chronic Exertional Dyspnea and Respiratory Muscle Function in Patients with Chronic Obstructive Pulmonary Disease

  • Published:
Lung Aims and scope Submit manuscript

Abstract.

The symptom of breathlessness is an important outcome measure in the management of patients with chronic obstructive pulmonary disease (COPD). Clinical ratings of dyspnea and routine lung function are weakly related to each other. However, in the clinical setting breathlessness in COPD is encountered under conditions of increased respiratory effort, impeded respiratory muscle action, or functional weakness. Thus, the present study was carried out to determine whether and to what extent clinical ratings of dyspnea and respiratory muscle dysfunction relate to each other. In 21 patients with COPD two methods were used to rate dyspnea: a modified Medical Research Council Scale (MRC) and the Baseline Dyspnea Index (BDI), which is a multidimensional instrument for measuring dyspnea based on three components: magnitude of task, magnitude of effort, and functional impairment. A baseline focal score was obtained as the sum of the three components. Measures were: pulmonary volumes; arterial blood gases; maximal voluntary ventilation (MVV); maximal inspiratory and expiratory pressures (MIP and MEP, respectively); and breathing patterns ventilation (VE), tidal volume (VT), and respiratory frequency (Rf). In 15 patients pleural pressure was also measured during both quiet breathing (Pplsw) and maximal inspiratory sniff maneuver at FRC (Pplsn). BDI and MRC ratings related to each other and showed comparable weak associations with standard parameters (FEV1, Paco 2, V T), MIP, and MEP. In contrast, MVV closely and similarly related to both ratings. Pplsw (%Pplsn), a measure of respiratory effort, and Pplsw (%Pplsn)/V T(%VC), an index of neuroventilatory dissociation, related significantly to both the BDI (r 2=−0.77 and r 2=−0.75, respectively) and the MRC (r 2= 0.81 and r 2= 0.74, respectively). Using MVV, Pplsw (%Pplsn), and Pplsw (%Pplsn)/V T(%VC) in a stepwise multiple regression as independent variables with BDI rating as dependent variable, MVV explained an additional 14.5% of the variance of the BDI over the 67.8% predicted by Pplsw (%Pplsn). Our results demonstrate that the level of chronic exertional dyspnea in COPD increases as the ventilatory muscle derangement increases. The level of the relationships among dyspnea ratings and MVV and respiratory effort helps to explain some of the mechanisms of chronic dyspnea of COPD. These measures should be considered for therapeutic intervention to reduce dyspnea.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Author information

Authors and Affiliations

Authors

Additional information

Accepted for publication: 30 December 1996

Rights and permissions

Reprints and permissions

About this article

Cite this article

Ferrari, K., Goti, P., Misuri, G. et al. Chronic Exertional Dyspnea and Respiratory Muscle Function in Patients with Chronic Obstructive Pulmonary Disease . Lung 175 , 311 –319 (1997). https://doi.org/10.1007/PL00007577

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/PL00007577

Navigation