Related Experiment Video
Updated: Jul 18, 2026

Employing the Forced Oscillation Technique for the Assessment of Respiratory Mechanics in Adults
Published on: February 9, 2022
Measuring bronchodilation in COPD clinical trials
Z L Borrill1, C M Houghton, A A Woodcock
1Medicines Evaluation Unit, North-west Lung Centre, Wythenshawe Hospital, Manchester, UK. zborrill@meu.org.uk
Aims:
The aim of this study was to compare the variability and sensitivity of impulse oscillometry (R5, X5 and RF), plethysmography (Raw and sGaw) and spirometry (FEV1, FVC and MMEF) in order to determine the most powerful technique for assessing bronchodilation in COPD clinical trials.
Methods:
Twenty-four patients with COPD had impulse oscillometry, plethysmography and spirometry measured twice 30 mins apart, to determine variability. Then ascending doses of salbutamol (20, 50, 100, 200, 400 and 800 microg) were given and the same measurements made after each dose. Significant changes greater than variability were determined for each performed measurement (expressed as mean percentage improvement with 95% CI).
Results:
Significant effects (P < 0.05) were detected after 20 microg by X5 (18.5% CI 9.8-27.2) RF (11.1% CI 7.2-15.0) and sGaw (21.5% CI 10.1-32.9), and after 50 microg by R5 (16.7% CI 10.8-22.5) and Raw (19.7% CI 13.0-26.4). FEV1 was less sensitive, detecting significant bronchodilation at 100 microg (10.2% CI 7.4-12.9).
Conclusions:
We conclude that impulse oscillometry and plethysmography should be considered the preferred techniques for measuring bronchodilation in COPD clinical trials.
Related Concept Videos
COPD: Management Using Bronchodilators and Corticosteroids
Chronic Obstructive Pulmonary Disease
Smoking is a primary risk factor for COPD, with over 80% of patients having a history of it. Patients typically experience progressive dyspnea or labored breathing, frequent coughing, and recurrent pulmonary infections. Many eventually succumb to respiratory failure, characterized by...
Chronic Obstructive Pulmonary Disease-I: Introduction
Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History
Chronic Obstructive Pulmonary Disease III: Chronic Bronchitis Features
Chronic Obstructive Pulmonary Disease IV: Clinical Manifestations

