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Pulmonary function with expiratory resistive loading in healthy volunteers
Jyotika Erram1, Monica Bari1, Antoinette Domingo1
1School of Exercise & Nutritional Sciences, San Diego State University, San Diego, California, United States of America.
Plos One
|June 11, 2021
Summary
Expiratory loading in healthy adults significantly reduced forced expiratory volume (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF). This method mimics obstructive lung disease mechanics without disease-specific variations.
Area of Science:
- Pulmonary Physiology
- Respiratory Mechanics
Background:
- Expiratory flow limitation is a hallmark of obstructive pulmonary diseases.
- Studying lung mechanics requires isolating flow limitation from disease-specific heterogeneities.
Purpose of the Study:
- To investigate the effects of imposed expiratory loading on lung mechanics in healthy adults.
- To simulate conditions resembling obstructive pulmonary diseases in a controlled setting.
Main Methods:
- Thirty-seven healthy volunteers underwent spirometry and body plethysmography.
- Expiratory threshold loading was applied at 7, 11, and 20 cmH2O.
- The rectangular area ratio (RAR) of the flow-volume loop was analyzed.
Main Results:
- Increased airway resistance (p<0.0001) and reduced FEV1, FVC, and PEF (p<0.0001) were observed with expiratory loading.
- No clinically significant changes in FEV1/FVC, FRC, or RAR were found.
- A concave expiratory flow-volume relationship was consistently absent under loading.
Conclusions:
- Imposed expiratory loading reduces key pulmonary function parameters (FEV1, FVC, PEF) in healthy individuals.
- This loading strategy mimics dynamic airway compression seen in obstructive lung diseases.
- Threshold loading may be a valuable tool for studying increased work of breathing and dynamic hyperinflation.
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