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Effect of maximal versus submaximal expiratory effort on spirometric values
Respiration; International Review of Thoracic Diseases
|January 1, 1981
Summary
Maximal expiratory effort may not always yield the highest spirometry results. Some individuals show improved forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) with submaximal efforts, suggesting varied patient responses in pulmonary function testing.
Area of Science:
- Pulmonary physiology
- Respiratory medicine
- Spirometry
Background:
- Flow-volume curves can paradoxically show lower mouth flow with maximal effort compared to submaximal effort.
- This observation suggests that maximal effort might not consistently produce the highest spirometric values.
Purpose of the Study:
- To investigate the impact of maximal versus submaximal expiratory effort on key spirometric values.
- To determine if submaximal efforts can yield larger pulmonary function measurements in certain individuals.
Main Methods:
- Subjects performed spirometry using both maximal and submaximal expiratory efforts.
- Key spirometric parameters including FVC, FEV1, and FEF25-75% were measured and compared between effort types.
Main Results:
- A significant increase in FVC, FEV1, or FEF25-75% with submaximal effort was observed in 12 out of 38 subjects.
- In these subjects, peak flows during submaximal efforts ranged from 65% to 91% of their maximal effort peak flows.
Conclusions:
- Spirometric values can be higher with submaximal expiratory effort in a subset of the population.
- These findings highlight the importance of considering patient effort variability in interpreting spirometry results.