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Normal values for inspiratory muscle function in children
Uwe Mellies1, Florian Stehling, Christian Dohna-Schwake
1Departement of Pediatric Pulmonolgy and Sleep Medicine, University of Essen, Children's Hospital, Hufelandstr. 55, 45122 Essen, Germany.
Insights
This study establishes normative data for inspiratory muscle function (IMF) in children, providing percentile curves for maximum inspiratory pressure (MIP) and other key metrics. These findings aid in assessing IMF in pediatric neuromuscular disorders.
Area of Science:
- Pediatric Pulmonology
- Neuromuscular Disorders
- Respiratory Physiology
Background:
- Assessment of inspiratory muscle function (IMF) in children with neuromuscular disorders is challenging due to a lack of standardized tests and normative data.
- Existing respiratory muscle tests are poorly validated for pediatric populations.
Purpose of the Study:
- To establish gender-specific and age-dependent normative data for key inspiratory muscle function parameters in healthy schoolchildren.
- To develop percentile curves for maximum inspiratory pressure (MIP) and other derived indices.
Main Methods:
- Investigated maximum inspiratory pressure (MIP), mouth occlusion pressure (P0.1), and inspiratory time in 301 healthy children aged 6-16 years.
- Derived inspiratory muscle load (P0.1/MIP) and tension time index (TTI).
- Generated gender-specific and age-dependent percentile curves and confidence intervals for all measured parameters.
Main Results:
- MIP was significantly higher in boys than girls, while P0.1/MIP and TTI were higher in girls.
- Developed regression equations for MIP based on age for both genders.
- Established 95% confidence intervals for MIP, P0.1/MIP, TTI, and P0.1, revealing wide interindividual variability.
Conclusions:
- The developed percentile curves and confidence intervals facilitate longitudinal assessment of individual pediatric patients.
- Normative IMF data and derived indices are crucial for accurate diagnosis and monitoring in pediatric neuromuscular disorders.
- These standardized measures can serve as appropriate endpoints in clinical trials for pediatric respiratory conditions.
Abstract:
Assessment of inspiratory muscle function (IMF) is limited in children with neuromuscular disorders, because respiratory muscle tests are poorly standardized and valid normative data are unavailable. We investigated maximum inspiratory pressure after exhalation to residual volume (MIP), mouth occlusion pressure (P0.1) and time of inspiration during quiet breathing and derived inspiratory muscle load (P0.1/MIP), and tension time index (TTI) in 301 healthy schoolchildren 6-16 years old. Gender-specific and age-dependent percentile curves for MIP were drawn with the median, 5%, 10%, 25%, 75% and 95% percentile. P0.1 was equal in boys and girls (0.23 ± 0.11 kPa), while MIP was significantly higher in boys (6.8 ± 2.2 versus 5.8 ± 2.4 kPa). Consequently, P0.1/MIP (4.8% ± 3.2% versus 4.0% ± 3.1%) and TTI (0.2 ± 0.14 versus 0.16 ± 0.14) were significantly higher in girls. MIP was 2.90 + 0.36 × age (kPa) and 3.19 + 0.24 × age (kPa) in boys and girls, respectively. The 95% confidence intervals for boys and girls, respectively, were MIP, 6.3-7.3 kPA and 5.4-6.2 kPa; P0.1/MIP, 3.5%-4.5% and 4.3%-5.3%; TTI, 0.14-0.18 and 0.18-0.22; and P0.1, 0.20-0.24 kPa for both. IMF in children has a wide interindividual variability; however percentile curves facilitate a longitudinal assessment of individual patients. Furthermore, narrow confidence intervals allow for comparisons of study populations, making IMF an appropriate endpoint for clinical trials.
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