Reference Values for Respiratory Muscle Strength in Children and Adolescents.

BACKGROUND

Measurement of respiratory muscle function is important in the diagnosis of respiratory muscle disease, respiratory failure, to assess the impact of chronic diseases, and/or to evaluate respiratory muscle function after treatment.

OBJECTIVES

To establish reference values for maximal inspiratory and expiratory pressure, and the tension-time index at rest in healthy children and adolescents aged 8-19 years, as well as to present sex- and age-related reference centiles normalized for demographic and anthropometric determinants.

METHODS

In this cross-sectional observational study, demographic, anthropometric, and spirometric data were assessed, as well as data on respiratory muscle strength (PImax and PEmax) and work of breathing at rest (TT0.1), in a total of 251 children (117 boys and 134 girls; mean age 13.4 ± 2.9 years). Reference values are presented as reference centiles developed by use of the lambda, mu, sigma method.

RESULTS

Boys had significantly higher PImax and PEmax values. Next to sex and age, fat-free mass appeared to be an important predictor of respiratory muscle strength. Reference centiles demonstrated a slight, almost linear increase in PImax with age in boys, and a less steep increase with age in girls. TT0.1 values did not differ between boys and girls and decreased linearly with age.

CONCLUSION

This study provides reference values for respiratory muscle strength and work of breathing at rest. In addition to sex and age, fat-free mass was found to be an important predictor of respiratory muscle strength in boys and girls.