The aim of this study was to determine the changes in respiratory regulation in patients with bronchial asthma in different phases of the disease and after pharmacological bronchodilation. This study was carried out on 10 healthy volunteers and 35 asthmatics. In order to assess the changes in respiratory regulation the respiratory response to increasing hypercapnia using the rebreathing method. Changes in minute ventilation (VE) and CO2 induced occlusion pressure (PO2) were analysed. The respiratory index and PO2 during quiet breathing were registered. It was found that patients with bronchial asthma have increased respiratory drive (increased VT/TI and PO2), with unchanged time control fo the respiratory cycle. The response to hypercapnic stimulation based on evaluation of occlusion pressure is two times higher bronchial asthma compared with healthy volunteers. The ventilatory response to CO2 is decreased proportionally to the degree of bronchoconstriction. Bronchodilating agents decreased respiratory drive and increased the CO2 ventilatory response. In 2 patients with a history of asthmatic states an individual low reactivity to CO2 was found, which could be the reason for respiratory insufficiency in them.
Adult Asthma