Estabilidade de Membrana de Eritrócitos em Pacientes Portadores de Doença Pulmonar Obstrutiva Crônica em Oxigenioterapia Domiciliar Prolongada

Abstract

Introduction: Chronic Obstructive Pulmonary Disease (COPD) is a debilitating and systemic inflammatory disease caused by irritants such as cigarette smoke. Patients present airflow reduction, which is not completely reversible and have progressive decreasing on life quality during disease progression. COPD has been associated with an increase on body’s oxidative stress which can modify erythrocyte’s membrane stability. Objective: The aim of this work is to investigate the existence of associations between erythrocyte membrane stability and respiratory, biochemical and hematological variables in patients with COPD in Long-Term Oxygen Therapy (LTOT) compared to healthy volunteers. Material and methods: The study population consisted of 145 men, 74 of the control group and 71 with COPD in LTOT. Biochemical and hematologic tests and evaluation of the erythrocytes osmotic stability were performed. Additionally, the six-minute walk test was applied and the pulmonary function was tested by spirometry. Results: The volunteers with COPD presented erythrocytes with greater stability both in isotonic and hypotonic conditions in relation to blood, concomitantly with lower hemoglobin levels and lower values of mean corpuscular hemoglobin concentration, as well as higher values of mean corpuscular volume and red-cell distribution width. Iron status and blood levels of total and indirect bilirubin, albumin, triglycerides, total cholesterol (C), VLDL-C and LDL-C were lower in the COPD group, suggesting a tendency to malnutrition. The erythrocytes osmotic stability was inversely correlated with the indicators of lung function, body mass index and physical capacity in this group. Conclusions: Individuals with COPD in LTOT showed osmotically more stable and heterogeneous erythrocytes, but this increased erythrocytes stability was associated with worsening of lung function, body mass index and physical capacity.