To determine whether the COPD impairs the diaphragmatic mobility (DM), and verify improvements after an inpatient pulmonary rehabilitation (PR).

Ultrasonography on M-mode will assess the diaphragmatic mobility at rest breathing and at slow deep inspiration. Lung functions test, arterial blood gas analyses, six minute walk test will be also performed, on COPD patients and healthy subjects.

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.

Statistical analyses:

The qualitative description of the data will be made with percentages and frequency. The quantitative data described as means and standard deviation for the symmetrical distributions. The Kolmogorov-Smirnov test to determine distributions mean normality. A One-way analysis of variance (ANOVA) with repeated measurements and Bonferroni test will be used as post-hoc test to evaluate statistical significance. Within-group effect sizes will be calculated using the Cohen d coefficient interpretation. For all the study data, the P values lower than 0.05 will be consider significant. The investigators will use the Student T- test for independent sample for quantitative data and for comparisons between the COPD patients and control group and ANOVA to the comparisons within COPD group. The investigators will use Pearson's correlation test to measure the correlation between the diaphragmatic mobility and the lung functioning variables.

Inclusion Criteria

• Clinical Diagnosis of Chronic Obstructive Pulmonary Disease (COPD)
• Informed consent signature

Exclusion Criteria:

• Subjects with Pneumothorax
• Subjects with Active hemoptyses
• Subjects with Acute heart failure
• Subjects with Systemic arterial hypertension
• Subjects with aortic aneurism
• Subjects who underwent Hepatic surgery
• Subjects who underwent Splenectomy surgery
• Subjects with Diaphragmatic paralysis Subjects with Neuromuscular diseases Subjects with Chronic orthopaedic diseases