The correlation between expiratory and inspiratory spirometric parameters during the bronchodilation test in asthmatic patients

<bold>Introduction:</bold> The bronchodilation test (BDT) involves administering a bronchodilator and measuring subsequent changes in spirometric parameters. It is a common diagnostic method for assessing the reversibility of airway obstruction in asthma. <bold>Objective:</bold> To evaluate the correlation between the response of expiratory (Forced Expiratory Volume in one second “FEV1” and Forced Vital Capacity “FVC”) and inspiratory (Forced Inspiratory Volume in one second “FIV1” and Forced Inspiratory Vital Capacity “FIVC”) spirometric parameters to BDT in asthmatic patients. <bold>Methods:</bold> This was a cross sectional study of 50 adults with asthma referred to our department (October-January 2023). Spirometry was performed for all patients. FEV1, FVC, FIV1 and FIVC before and after BDT, were measured. ΔFEV1, ΔFVC, ΔFIV1 and ΔFIVC were calculated as percentage of change from baseline. <bold>Results:</bold> Mean age was 45.12±17.41 years. Spirometric profiles were distributed as follows : 61% had normal spirometry, 25% had an obstructive ventilatory disorder and 14% had a restrictive ventilatory disorder. Means of FEV1(%), FVC(%), FIV1(%) and FIVC(%) before BDT were 91.17±14.8, 87.88±12.04, 97.76±16.95 and 84.11±12.71. Means of FEV1(%), FVC(%), FIV1(%) and FIVC(%) after BDT were 96.05±13.10, 91.64±9.31, 99.88±12.96 and 87±10.82, respectively. Mean of ΔFEV1, ΔFVC, ΔFIV1, ΔFIVC were, respectively, 4.88%, 3.76%, 2.11% and 2.88%. ΔFEV1 were correlated with ΔFIV1 (p<0.05 ; r=0.575) as well as ΔFVC were correlated with ΔFIVC (p<0.05; r=0.579). <bold>Conclusion:</bold> This correlation highlights the importance of assessing both expiratory and inspiratory parameters when monitoring lung function in asthma.