Erythrocytes Membrane Stability in COPD Patients in Long-Term Home Oxygen Therapy

Chronic Obstructive Pulmonary Disease (COPD) patients in Long-Term Home Oxygen Therapy (LTOT) have a reduction in airflow that is not totally reversible. This obstruction may be associated with an abnormal inflammatory response of the lungs as a result of inhalation of toxic particles, particularly to cigarette smoke. Furthermore, COPD patients also present limited symptoms to physical exercise, significant extrapulmonary effects, including weight loss, nutritional abnormalities and skeletal muscle dysfunction. Hyperinflation has been identified as a major cause of dyspnea and is currently believed to be already present in the early stages of the disease, causing limitations in physical capacity. The progressive exertional dyspnea is most associated with impairment to activities of daily living, decreased quality of life and worse prognosis. Traditionally, the severity of COPD is defined by the degree of obstruction, as measured by forced expiratory volume in one second (FEV1) after bronchodilator use (post-BD) and can be classified as mild, moderate, moderately severe and very severe disease. In the group of patients with Advanced Pulmonary Disease (APD), those with partial pressure values of oxygen (PaO2) lower or equal to 55mmHg, or arterial oxygen saturation (SaO2) lower or equal to 88% in ambient air; or those with PaO2 values between 55-60 or SaO2 lower than 90%, with evidence of pulmonary hypertension or polycythemia require LTOT, over 15 hours / day, with evidence of increased survival. The aim of this study is to evaluate the erythrocyte membranes stability in COPD and APD patients in LTOT compared to healthy subjects. It is a cross-sectional, observational study with evaluation of erythrocyte membranes stability among the groups as well as lung function, physical testing, laboratory analysis, oxidative stress and quality of life questionnaires. As red blood cells are the cells responsible for the gas exchange in the lungs and peripheral tissues, and since the patients with COPD and APD have gas exchange impairment compared to the healthy group, it is expected to find a difference in erythrocyte membranes stability and levels of oxidative stress among the groups.

COPD is a major cause of illness and death worldwide, representing a significant economic and social cost. In the household, it causes concern, limited social life and leisure; commits the budget and shortens life. In the professional field, reduces productivity, anticipates the retirement and results in pension payments and benefits. In the area of health system, motivates repeated calls in emergency rooms, outpatient clinics and is a frequent cause of hospitalizations, which causes high costs for government and society. Most cases can be attributed to smoke.

COPD is often developed in middle-aged smokers with long time exposure which have a variety of other diseases related to smoking or aging. COPD itself has also significant extra-pulmonary effects (systemic) that lead to comorbid conditions. Nutritional abnormalities, weight loss and skeletal muscle dysfunction are well-recognized extrapulmonary effects of COPD and patients are at high risk for myocardial infarction, osteoporosis, respiratory infection, bone fractures, depression, sleep disorders, anemia and glaucoma.

Thus, this study aims to investigate the erythrocyte membranes stability in patients with COPD compared to healthy individuals, since the loss or damage of the red blood cells may be related to worsening gas exchange of patients and caused, for example, by increased oxidative stress observed in the disease mechanism of COPD patients, especially those with advanced lung disease.

Cross-sectional, observational study, which will be compared COPD patients with Advanced Lung disease using Long-Term Home Oxygen Therapy to healthy subjects to evaluate the presence of difference in membrane stability in the red blood cells as well as differences in pulmonary function tests, physical tests, laboratory analysis and presence of oxidative stress, as well as their quality of life.

The results obtained after analysis of erythrocyte membranes stability, as well as oxidative stress and functional and laboratory tests will be correlated, both in patients with COPD Long-Term Home Oxygen Therapy as the control group in order to establish relationships between variables and also compare between groups to determine the differences among them.

Eligibility Criteria:
Inclusion Criteria:

1. Control Group

   * Patients without significant cardiorespiratory disease diagnosed, matched for age and body mass index to the group of COPD patients and APD in LTOT;
   * Nonsmoker;
   * Age group over 40 years old;
   * Male gender;
   * Acceptance to participate and agreement to sign the Informed Consent Term
2. COPD Group in LTOT

   * Patients with COPD and APD in LTOT;
   * Patients who do not have associated severe heart disease;
   * Patients with no pulmonary exacerbations in the past four weeks;
   * Male gender;
   * Age group over 40 years old;
   * Acceptance to participate and agreement to sign the Informed Consent Term

Exclusion Criteria:

* Patients with a disability or orthopedic disfunction that unable mobility or performance of physical tests;
* Patients using lipid-lowering drugs such as statins and fibrates;
* Patients or family / guardians who refuse to sign the Informed Consent Term