Respiratory Impedance and Response to Salbutamol in Healthy Individuals and Patients with COPD

Abstract

Background: Recent studies suggested that the bronchodilator response depends on airway obstruction. The forced oscillation technique (FOT) may help improve our understanding of the changes in respiratory mechanics that occur after the application of a bronchodilator. Objectives: We aimed to (1) assess the response to salbutamol and to compare the impedance changes in healthy individuals and COPD patients, (2) investigate the effects of airway obstruction on this response and (3) evaluate the utility of the FOT as a complementary measurement to assess the response to the bronchodilator. Methods: Twenty-five healthy individuals and 82 patients with COPD were assessed with the FOT followed by spirometry before and after the use of salbutamol. Results: The changes exhibited by the COPD subgroups were greater than in the healthy individuals (p < 0.05). Increased obstruction resulted in decreased reductions in mean resistance and increased improvements in mean reactance (p < 0.001). In addition, the bronchodilation reduced the ventilation heterogeneity and the impedance modulus in all COPD stages (p < 0.05). The correlation coefficients for the spirometric and FOT changes were low (0.21-0.38). Conclusions: In the initial phases of COPD (stage I), the effects of bronchodilation are greater than in healthy volunteers. The bronchodilator use improved the oscillatory mechanics in all of the studied groups of COPD patients. These improvements are reduced in more advanced phases of airway obstruction (II, III and IV). The FOT provides information that complements the data supplied by spirometry, contributing to an improvement in the evaluation of the bronchodilator response in COPD.

Bronchodilator response of advanced lung function parameters depending on COPD severity

“…This is almost in accordance with the findings of da Costa et al15 regarding bronchodilator response using FOT, since we had more patients with milder disease.…”

“…The response of parameters of forced oscillometry (FOT) after salbutamol has recently been described in different GOLD stages. These data showed a significant response in milder stage of COPD compared to controls with a tendency of lower response in more advanced stage 15. However, the bronchodilator response of parameters measured by the closely related IOS method and volume parameters measured by body plethysmography in correlation to other parameters has not been investigated in relation to COPD disease severity based on FEV 1 %p.…”

Evaluation of Inhaled Procaterol for Potential Assist Use in Patients with Stable Chronic Obstructive Pulmonary Disease

“…Although several authors reported the usefulness of FOT parameters in evaluating COPD [10,19], it is not widely used for this purpose. This is probably due to its high cost, low repeatability [20], and high variances caused by the upper airway structure [21].…”

Bronchodilator response of advanced lung function parameters depending on COPD severity

“…advanced lung function bronchodilation in COPD findings of da Costa et al 15 regarding bronchodilator response using FOT, since we had more patients with milder disease.…”

“…These data showed a significant response in milder stage of COPD compared to controls with a tendency of lower response in more advanced stage. 15 However, the bronchodilator response of parameters measured by the closely related IOS method and volume parameters measured by body plethysmography in correlation to other parameters has not been investigated in relation to COPD disease severity based on FEV 1 %p.…”