Objective: To evaluate the health-related quality of life of patients with chronic obstructive pulmonary disease receiving long-term oxygen therapy (LTOT) at home through oxygen cylinders and compare these results with those obtained six months after the transition from oxygen cylinders to oxygen concentrators. Methods: A total of 45 patients were evaluated. Of those, 24 had chronic hypoxemia and 21 presented no evidence of hypoxemia. The patients with chronic hypoxemia had been regularly receiving LTOT for at least the last six months and were evaluated at baseline, while using cylinders, and six months after the transition from cylinders to concentrators. The non-hypoxemic patients were evaluated at the same time points as were the hypoxemic patients. In order to evaluate quality of life, a version of the Saint George's Respiratory Questionnaire (SGRQ), translated and validated for use in Brazil, was administered. Results: At baseline, quality of life, as evaluated using the total score and the symptom and impact domain scores of the SGRQ, was more impaired in the hypoxemic patients than in the non-hypoxemic patients. After six months of using the concentrators, the hypoxemic patients presented a significant improvement in the quality of life, and, at that time, no difference was found between the patients with and without hypoxemia. Conclusion: Our findings show that quality of life is impaired in patients with chronic obstructive pulmonary disease and chronic hypoxemia, that their quality of life can be improved through regular use of LTOT, and that the oxygen delivery system has an influence on this improvement.

Keywords: Pulmonary disease, Chronic obstructive; Anoxemia; Oxygen inhalation therapy; Quality of life.

Chronic obstructive pulmonary disease is progressive and is characterized by abnormal inflammation of the lungs in response to inhalation of noxious particles or toxic gases, especially cigarette smoke. Although this infirmity primarily affects the lungs, diverse extrapulmonary manifestations have been described. The likely mechanisms involved in the local and systemic inflammation seen in this disease include an increase in the number of inflammatory cells (resulting in abnormal production of inflammatory cytokines) and an imbalance between the formation of reactive oxygen species and antioxidant capacity (leading to oxidative stress). Weakened physical condition secondary to airflow limitation can also lead to the development of altered muscle function. Chronic obstructive pulmonary disease presents diverse systemic effects including nutritional depletion and musculoskeletal dysfunction (causing a reduction in exercise tolerance), as well as other effects related to the comorbidities generally observed in these patients. These manifestations have been correlated with survival and overall health status in chronic obstructive pulmonary disease patients. In view of these facts, the aim of this review was to discuss findings in the literature related to the systemic manifestations of chronic obstructive pulmonary disease, emphasizing the role played by systemic inflammation and evaluating various therapeutic strategies.

Keywords: Pulmonary disease, chronic obstructive/complications; Nutritional status; Exercise tolerance;