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Determination of peak expiratory flow
S Kano1, D L Burton, C J Lanteri
1Division of Clinical Science, W.A. Research Institute for Child Health, Perth.
The European Respiratory Journal
|October 1, 1993
Summary
Peak expiratory flow (PEF) is influenced by airway mechanics, not solely wave speed. Breathholds at total lung capacity (TLC) and neck flexion reduced PEF, suggesting airway wall compliance affects flow limitation.
Area of Science:
- Respiratory Physiology
- Pulmonary Mechanics
Background:
- Peak expiratory flow (PEF) is a key measure of airflow limitation.
- The role of "wave speed" (Vws) in determining PEF remains unclear.
- Airway mechanical properties may influence PEF.
Purpose of the Study:
- To investigate the impact of airway mechanical properties on PEF.
- To determine if PEF is limited by wave speed.
- To explore the effects of breath-holding and neck position on PEF.
Main Methods:
- Five healthy adults performed maximal forced expiratory effort (MFEE) maneuvers.
- Measurements included spirometry and pneumotachography.
- Variations included breath-holds at total lung capacity (TLC) (2s, 10s), Valsalva maneuver, and neck flexion/extension.
Main Results:
- Breath-holds at TLC (2s, 10s) and neck flexion significantly reduced PEF (approx. 9-10%).
- These reductions occurred despite consistent respiratory effort.
- Neck extension and Valsalva maneuver did not increase PEF.
Conclusions:
- The findings do not refute the "wave-speed" hypothesis for PEF.
- Breath-holding at TLC may increase airway compliance, potentially reducing achievable "Vws".
- Airway wall stress relaxation during breath-holds could influence PEF.