Abstract
Background: Reduced respiratory muscle force and endurance are commonly observed in patients with COPD and contributes to dyspnea, oxygen desaturation and reduced exercise capacity, hence respiratory muscle assessment is clinically relevant.
Aim: To propose an assessment method of respiratory muscle endurance in patients with COPD and to verify it relationship with maximal inspiratory pressure (MIP) and maximal voluntary ventilation (MVV).
Method: 18 patients (GOLD 1-4; 63±9years) performed the MIP and an incremental and constant respiratory muscle endurance test using the PowerBreathe® device. The incremental test started with 10cmH2O, increasing 10cmH2O each 2min, with 1min of rest between them, which determined the maximal pressure sustained (MPS). The endurance test was 80% of the MPS. The limit time (tlim) was determined. Comparisons and correlations were determined using Paired t-test and Pearson correlation.
Results: The MIP was 52±20cmH2O, MVV (%pred) 44±15, MPS 48±23cmH2O, tlim 10±8 min and 80%MPS 35±21cmH2O. The MIP and MPS were not different. Correlation was found between MIP and MPS (r=0.5; p=0.03) and MIP and MVV (r=0.6; p=0.03).
Conclusion: The MPS and MIP were similar in the endurance test and showed a relationship with MVV; with suggest to be a reasonable test to assess the respiratory performance in these patients.
Funding: CAPES - Brazil
- © 2011 ERS