Respiratory muscle dysfunction is a common problem in patients with COPD, mostly related to pulmonary hyperinflation. A reduced diaphragm and harmful changes in the length-tension relationship of muscles cause a reduction in the ability of muscles to generate force, which results in a mechanical disadvantage in this type of patients.

Until now, the only way to evaluate a dysfunction of respiratory muscles was to measure the relationship between the transdiaphragmatic pressure and the electrical activity of the diaphragm, which involves invasive methods that cause discomfort to patients.

Raimón Jané, leader of  Biomedical Signal Processing and Interpretation at IBEC, in collaboration with the Hospital Germans Trias i Pujol  and Hospital del Mar, has used the mechanomyography (MMG) technique in respiratory muscles —a noninvasive method to measure mechanical vibrations related to muscle activation using accelerometers placed on the skin— to evaluate the function of  respiratory muscles in 10 patients with severe or very severe COPD.

The study, which has been published in the European Respiratory Journal, consisted in making patients breathe normally through a filter and a tube while wearing a nose clip, which allowed researchers and clinicians to obtain, for the first time, a direct comparison between the mechanical activation of  inspiratory muscles, estimated through the amplitude of the MMG, and the inspiratory effort in relation to tidal volume —the volume of air moved in and out of the lungs during restful breathing.

The researchers are hopeful that that their contribution may be a very useful tool to assess the progression of COPD, and that it could provide valuable information on the effects of treatments.

More information at IBEC website.