Related Experiment Videos
Effects of thoracic gas compression on maximal and partial flow-volume maneuvers
R D Fairshter1, R B Berry, A F Wilson
1University of California, Irvine Medical Center, Orange 92668.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|August 1, 1989
Summary
Comparing maximal (MEFV) and partial (PEFV) expiratory flow-volume curves helps evaluate airway hysteresis. While gas compression artifacts affect spirometry, this study found that these artifacts generally do not prevent accurate identification of airway hysteresis.
Area of Science:
- Pulmonary Physiology
- Respiratory Mechanics
Background:
- Airway hysteresis is assessed using maximal (MEFV) and partial (PEFV) expiratory flow-volume curves.
- Pulmonary function systems can introduce gas-compression artifacts, potentially affecting MEFV and PEFV curve accuracy.
Purpose of the Study:
- To simultaneously measure MEFV and PEFV curves using both spirometry and volume-displacement plethysmography.
- To investigate the impact of gas-compression artifacts on airway hysteresis measurements in normal and asthmatic subjects.
Main Methods:
- Simultaneous acquisition of MEFV and PEFV curves using a spirometer and a volume-displacement plethysmograph.
- Comparison of flow rates and alveolar pressures between the two measurement techniques.
- Analysis of Vmax-p/Vmax-c ratios to assess airway hysteresis.
Main Results:
- Plethysmographic flow rates were consistently higher than spirometric flow rates for both MEFV and PEFV maneuvers.
- The qualitative findings regarding the presence or absence of airway hysteresis were consistent between the two methods.
- Alveolar pressure differences between MEFV and PEFV maneuvers were observed, particularly in asthmatic subjects.
Conclusions:
- Volume-displacement plethysmography provides a method free from gas-compression artifacts for evaluating airway hysteresis.
- Despite quantitative differences in ratios, spirometry can generally still identify airway hysteresis even with gas-compression artifacts.