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Maximum expiratory flow-volume curves in children: changes with growth and individual variability

S R Leeder, A V Swan, J K Peat

    Bulletin Europeen De Physiopathologie Respiratoire
    |March 1, 1977
    PubMed

    Insights

    Detecting environmental impacts on children's lung development requires large studies. Measuring maximum expiratory flow-volume (MEFV) curves revealed growth differences between boys and girls, with significant sample sizes needed to track lung function changes.

    Area of Science:

    • Pediatric Pulmonology
    • Environmental Health
    • Respiratory Physiology

    Background:

    • Environmental factors can impede children's lung growth and ventilatory capacity.
    • Understanding normal lung function growth patterns is crucial for identifying deviations.

    Purpose of the Study:

    • To assess normal growth patterns of maximum expiratory flow-volume (MEFV) curves in children aged 8-14 years.
    • To determine the accuracy of measuring deviations from normal growth in ventilatory capacity.
    • To calculate the sample sizes needed for detecting retarded lung growth.

    Main Methods:

    • Recorded MEFV curves in boys and girls aged 8-14 years.
    • Analyzed expiratory flow rates, timed expiratory volumes, and forced vital capacity (FVC).
    • Calculated reproducibility of measurements and minimum sample sizes for detecting growth changes.

    Main Results:

    • Girls exhibited different MEFV curve shapes than boys, with higher maximum expiratory flow rates (Vmax.) adjusted for FVC.
    • The ratio of Vmax. 50% FVC to FVC decreased with age in both sexes.
    • Detecting a 10% change in Vmax. 50% FVC growth rate annually requires nearly 2,000 children; smaller samples suffice for FVC growth concerns.

    Conclusions:

    • Significant sample sizes are necessary to detect subtle environmental effects on children's lung growth.
    • MEFV curve analysis provides insights into sex-based differences in pediatric respiratory development.
    • Future research should consider these sample size requirements for environmental exposure studies.

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