Respiratory and muscular dysfunction of the respiratory muscles and chronic obstructive pulmonary disease: pathophysiological relationships and clinical significance

Abstract

The review presents literature data on the problem of respiratory muscle (RM) dysfunction in patients with chronic obstructive pulmonary disease (COPD). The main features of their pathophysiological interactions and clinical practice values were observed. Both local and systemic factors of the pathogenesis of COPD are important in the development of RM dysfunction. Local factors are associated with lung remodeling and the need of RM to overcome excessive breathing resistance, which increases the intensity of their work, and contributes to the development of hypertrophy and insufficiency. Chronic systemic inflammation, oxidative stress, excessive proteolysis and other systemic manifestations of COPD change the metabolism, structural and functional organization of RM. The severity of morpho-functional disorders and metabolic status of RM depends on the gravity of COPD and emerges on the early stages as myocytes’ hypertrophy, their increasing capillarization and the increasing of mitochondrion density. At late stages it appears as diffuse replacement of muscle fibers by connective tissue. Low nutritional status, increasing protein-energy deficiency, electrolyte imbalance, endocrine disorders on the background of progressive respiratory insufficiency and tissue hypoxia contribute to the development of RM weakness. The combination of COPD, acute disorders of cerebral circulation and chronic heart failure sharply worsens the function of RM and the prognosis of comorbid diseases. Also, the dysfunction of RM in patients having COPD is significantly aggravated at the age of senility. The review discusses the possibilities of pharmacological correction of RM dysfunction and other clinical aspects of this problem.