CHANGES IN BODY PLETHYSMOGRAPHY PARAMETERS AFTER BRONCHODILATATION TEST

Abstract

Background. Small airways, due to specific anatomical and physiological features, usually do not cause obvious spirometric changes. Therefore, in order to assess both the condition of the small airways and their response to treatment, a more detailed assessment of lung function is appropriate. The aim of the study. To evaluate changes in plethysmography-derived indices of the body after bronchodilatation test in patients with chronic obstructive pulmonary diseases, and compare it with spirometric indicators. Methods. A prospective study was conducted in respondents with chronic obstructive pulmonary disease (COPD) (n=21) and asthma (n=21). Spirometry and body plethysmography were performed prior and after 20 min of inhalation of 400 µg salbutamol. Based on the results of the bronchodilation test (ΔFEV1≥12% and ≥200 ml from baseline), subjects were divided into two groups: positive and negative response. Results. A total number of 42 middle-aged (59.8±2.1 yrs.) subjects were studied. A positive response was found in 12 subjects (28.6%), a negative – in 30 individuals (71.4%). In both study groups, there was a significant decrease in sRaw and an increase in sGaw after salbutamol inhalation, but FRC, RV, RV/TLC changed only in
the positive response group. Statistically significant correlations were found in both groups between FEV1, and sRaw, RV/TLC before and after bronchodilatation test. In both groups, a significant correlation was found between FEV1 and RV values before bronchodilatation test. Conclusion. Comparing with spirometry body plethysmography provides more detailed information about airways, especially small airways dysfunction in patients with obstructive pulmonary diseases.