Diaphragmatic Mobility, Lung Hyperinflation and Effects of the Pulmonary Rehabilitation

The diaphragm pathophysiological changes occurring in chronic obstructive pulmonary disease (COPD) leads to functional inefficiency that strongly correlates to the loss of lung function. Muscle fiber shortening follows lung hyperinflation, resulting to a chronic mechanical disadvantage, which worsens in COPD exacerbations. The DM is mostly assessed with techniques that exposes the patient to risks. The ultrasonography on M-mode is easy to use, safe and measures directly the diaphragmatic dome displacement. The study aim to determine whether the COPD impairs the DM, and verify improvements after an inpatient PR.

Every COPD patient will comprise a standard evaluation that consists on lung function test, six minute walk test and arterial blood gas analyses, according to the American Thoracic Society/ European Respiratory Society (ATS/ERS) statements.

Within the second day of recovery the diaphragm mobility ultrasonographic (US) measurement will be assessed as follow: the patients positioned in a semi recumbent position (45 degrees).The US probe positioned between the anterior and mean axillary line, on the central right subcostal area, cranial and dorsal. The US wave perpendicularly on the posterior hemidiaphragm third (it is visualized as the hyperechogenic line behind the liver). The mobility assessed by M-mode while the patient breaths on tidal volume (rest breathing) and deep slow breathing (to Functional Residual Capacity).

The COPD patients classification and diagnosis will be according to the the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. Every patient, after the assessment will follow the PR as ATS/ERS statement on pulmonary rehabilitation. All patients will follow a routine of five days a week of physical exercise. The rehabilitation program consists on a 30 minutes calisthenic gymnastic once a day, 20 minutes of cycloergometer training activity twice a day. The aerobic cycloergometer training was set at 60%-70% of the maximum cardiac frequency determined by 220 minus the patients age. The patients will perform lower limbs strengths exercises, especially for the quadriceps and hamstring. During the in-hospital stay, the patients will receive regular prescribed medication and oxygen therapy according to the medical staff evaluation, which will be prescribed by the clinician in charge. The patients will also have respiratory physiotherapy, regarding the presence of lung secretion retain, and the need to expand unventilated areas.

The control group will be composed by healthy volunteers. The volunteers will be screened on their lung function. The subjects on the control group will be submitted to the same evaluation protocol regarding the spirometry and the M-mode ultrasonography.