Differences in the elastic work of breathing of the pulmonary parenchyma in patients with bronchial asthma and COPD

Abstract

To determine and compare the work of breathing to overcome elastic resistance (Ael) in patients with bronchial asthma (BA) and chronic obstructive pulmonary disease (COPD) with similar changes in the elastic properties of the parenchyma in the same settings of ventilation disorders (grade 1). Differences in the manifestations of similar changes in the elastic properties of the lungs in patients with BA and COPD were evaluated. To identify differences, a comparative study was conducted on Аel overcome in BA patients with positive bronchodilator (with salbutamol) and bronchoconstrictor (with methacholine) tests, with reduced and preserved bronchial conductance (groups 1 and 2, respectively), and in COPD patients with negative bronchodilator and bronchoconstrictor tests (group 3). All study patients showed a grade 1 lung ventilation disorder (a decrease in the one-second forced expiratory volume by 15-35%). The results were compared with each other and with the control group (group 4, healthy non-smokers). All study patients were comparable by age and sex. The respiration mechanics was studied using simultaneous registration of spirogram and transpulmonary pressure, and the parameters of bronchial conductance and ventilation were determined using body plethysmopressography using the Jager software and hardware system. In COPD patients, Ael was significantly increased (p>0.05), whereas in both BA groups, it was unchanged. Increased elastic work of breathing in patients with COPD may be associated with the involvement of certain types of contractile elements, which are preserved in patients with BA at the initial stages of the disease.