Forced Oscillation Technique (FOT) and Expiratory Flow Limitation (EFL)
The aim of this study is to distinguish COPD patients with expiratory flow limitation in body plethysmography (open loop) from the patients without expiratory flow limitation in body plethysmography (closed loop) with the obtained FOT parameters.
|Study Design:||Observational Model: Case Control
Time Perspective: Prospective
|Official Title:||Diagnosing Expiratory Flow Limitation in COPD Patients With the Forced Oscillation Technique Using Linear Regression in the Time Frequency Domain|
|Study Start Date:||November 2006|
|Study Completion Date:||April 2008|
|Primary Completion Date:||April 2008 (Final data collection date for primary outcome measure)|
In daily practice the expiratory flow limitation is measured by body plethysmography. An open loop in body plethysmography shows expiratory flow limitation in COPD patients. But body plethysmography requires that the patient quietly sits in a closed box and is not able to follow changes breath by breath. The goal of this study is to validate the Forced oscillation technique (FOT) for measuring expiratory flow limitation in COPD patients.30 COPD patients with an open loop in body plethysmography are compared to 30 COPD patients with a closed loop. The methods used in this study are the maximal overlap discrete short time Fourier transform (MODFT) combined with a total least squares analysis. It is hypothesized that the obtained FOT parameters are able to distinguish the patients with expiratory flow limitation in body plethysmography from the patients without expiratory flow limitation in body plethysmography.Secondary study questions are: 1) to what extend are the FOT parameters distorted by breathing artifacts and measurement noise. 2)What changes can be detected by FOT in expiratory flow limitation after administration of salbutamol.