Objective To observe the clinical characteristics of asthma patients with chronic duration stage combined with small airway dysfunction (SAD), and analyze the influencing factors of SAD and the cardiopulmonary function of such patients under exercise. Methods The patients with chronic duration of asthma admitted to Nanjing Affiliated Hospital of Traditional Chinese Medicine from July 2022 to April 2024 were divided into a SAD group and a non-SAD group according to the lung function results. Clinical data and relevant data of cardiopulmonary exercise test (CPET) were collected, the clinical data and cardiopulmonary function between the two groups were compared. The influencing factors of SAD were explored by multivariate logistic regression analysis. Results A total of 102 patients with chronic asthma duration, 59 (57.8%) in the SAD group and 43 (42.2%) in the non-SAD group were included. In the SAD group, age, body masss index, asthma duration were greater than those in the non-SAD group, and SAD score was lower than that in the non-SAD group; the proportion of patients with acute onset of asthma, history of smoking, allergic rhinitis, and asthma control test score were higher than those in the non-SAD group, the exhaled nitric oxide level of SAD group was higher than that in the non-SAD group, and the conventional lung function level was lower than that in the non-SAD group (P<0.05). CPET showed that the VE/VCO2 slope and CO2 equivalent in the SAD group were higher than those in the non-SAD group, and the peak kg oxygen uptake, peak heart rate, and respiratory reserve were lower than those in the non-SAD group, showing a statistically significant difference (P<0.05). Multivariate logistic analysis showed that age, increase of carbon dioxide equivalent at peak exercise, acute onset of asthma and allergic rhinitis were independent risk factors for SAD, and the increase of peak expiratory flow rate was the protective factor (P<0.05). Conclusions SAD in chronic persistent asthma is affected by various factors such as age, acute asthma attacks and history of allergic rhinitis. CPET indicates that patients with asthma who also have SAD have their cardiopulmonary function and aerobic capacity impaired to some extent.
Objective To explore the characteristics of exercise ventilation function in patients with chronic duration of asthma, and the correlation of cardiopulmonary exercise test and control level and conventional lung function in patients with chronic duration of asthma. Methods Seventy-three patients with chronic duration of asthma admitted from December 2021 to December 2022 were recruited in the study. The asthma control level was assessed with the asthma control test (ACT) and the patients were divided into a well-controlled group and a poorly-controlled group. Routine pulmonary function test (PFT) and cardiopulmonary exercise test (CPET) were performed in both groups, to analyze the difference of related parameters between the two groups and observe the correlation between CPET and PFT, ACT score in the patients with chronic persistent asthma. Results CPET results showed that the VE/VCO2 slope, anaerobic threshold carbon dioxide equivalent (EqCO2@AT), and physiologically ineffective peak during exercise (VD/VTpeak) were higher in the poorly-controlled group than those in the well-controlled group (all P<0.05). The peak minute ventilation (VEpeak) and tidal volume (VTpeak) of the patients in the poorly-controlled group were lower than those in the well-controlled group (both P<0.05). The peak respiratory rate (BFpeak) and respiratory reserve (BRpeak) of the two groups were not significantly different (both P>0.05). The results of correlation analysis showed that the VE/VCO2 slope, EqCO2@AT, VD/VTpeak were negatively correlated with ACT score, and VEpeak was positively correlated with FVC%pred and MMEF%pred in the patients with chronic persistent asthma. BRpeak was positively correlated with FEV1%pred, FEV1/FVC%pred, MMEF%pred in routine pulmonary function. Multivariate logistic regression analysis showed that the increase of VE/VCO2 slope and VD/VTpeak were independent risk factors for poor asthma control (P<0.05). Conclusions Patients with poorly-controlled asthma have decreased exercise ventilatory function, mainly showing decreased ventilation and tidal volume during peak exercise and decreased ventilatory efficiency. There is some correlation between exercise ventilatory function and conventional lung function of control level in patients with chronic duration of asthma. The relevant indicators of ventilation efficiency in CPET have suggestive significance for asthma that is not well controlled, so it is necessary to carry out CPET in patients with asthma to improve the comprehensive evaluation of asthma.