Quadriceps Endurance Increases Following Cycling Exercise With Non-Invasive Ventilation In Moderate-To-Severe COPD Patients. A Non-Randomized Controlled Study

Abstract

Purpose

Application of non-invasive ventilation (NIV) during exercise improves exercise tolerance in severe COPD patients; however, the underlying mechanism is only partially unraveled. As part of its known effect to unload the respiratory muscles, we looked for the influence of NIV on post-exercise quadriceps muscle endurance.

Patients and methods

We included 25 severe COPD patients entering an outpatient pulmonary rehabilitation program. They performed, on successive days, three quadriceps endurance tests at 70% of the maximal strength (1RM) to task failure (TlimQ); 1) control condition; 2) following constant load cycling exercise to exhaustion without Inspiratory Pressure Support (TlimQ IPS-); 3) following the same cycling exercise with IPS (TlmQ IPS+).

Results

Dyspnea Borg score was significantly reduced at the end of the constant load cycling exercise with IPS+ compared to IPS- (3.5±2.6 to 4.3±2.3, p<0.05). Compared to controlled condition, TlimQ was reduced from 78.9±22.7 s to 64.7±22.1 s (p<0.01) with IPS+ and to 48.9±13.7 s (p<0.001) with IPS-. Sensitive analysis revealed a positive effect of NIV on TlimQ in only 15 of the 25 included patients (60%) and was unpredictable from exercise tolerance or maximal quadriceps strength.

Conclusion

Using a simple muscle endurance test, we showed the protective effect of NIV on the exercise-induced quadriceps dysfunction. This beneficial effect is inconstant in our small series of patients and could not be predicted by exercise capacity or endurance to exercise. However, measuring quadriceps muscle endurance following a session of exercise could determine in which patient NIV would improve the benefit of pulmonary rehabilitation.

Keywords:

• limb muscle
• endurance
• non-invasive ventilation
• exercise
• COPD

Acknowledgment

This study was promoted by CHU St Etienne, France, and partly supported by a grant from Association Lyonnaise de Logistique Posthospitalière, Lyon, France.

Author Contributions

FC, PL and ICF made substantial contributions to the conception, design, and/or interpretation of data; PL conducted experiment; MB, LF and SV contributed to data analysis. FC and PL analyzed data and wrote the manuscript. All authors contributed to drafting and revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflict of interest related to this work.