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Frequency dependence of oscillatory resistance in healthy primary school children
C E Cuijpers1, G Wesseling, G M Swaen
1Department of Epidemiology, University of Limburg, The Netherlands.
Insights
Negative frequency dependence of resistance (FD) is common in healthy children aged 5-12, decreasing with growth and varying by gender. This finding does not necessarily indicate lung disease.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Respiratory input impedance is a key measure of lung function.
- Understanding normal variations in children is crucial for diagnosing respiratory conditions.
Purpose of the Study:
- To investigate respiratory input impedance in healthy children aged 5-12 years.
- To analyze variations in impedance with height and gender.
- To determine the prevalence and characteristics of negative frequency dependence of resistance (FD).
Main Methods:
- Forced oscillation technique used to measure respiratory input impedance.
- Study included 371 healthy children aged 5-12 years.
- Analysis of impedance values in relation to height, gender, and frequency.
Main Results:
- Negative FD between 8 and 28 Hz was common in all height categories.
- Increasing height correlated with decreased resistance and increased reactance.
- Gender-based differences in resistance and reactance were observed, particularly below 140 cm height.
- Negative FD incidence decreased with growth, with more pronounced FD in boys over certain height ranges.
Conclusions:
- Negative FD between 8 and 28 Hz is a normal finding in healthy children up to 12 years old.
- The prevalence and characteristics of negative FD vary with age, height, and gender.
- These findings suggest that negative FD in this age group does not necessarily imply pulmonary pathology.
Abstract:
With the use of the forced oscillation technique, respiratory input impedance was measured in 371 healthy children, aged 5-12 years. How impedance values varied with height (age) and gender and to what extent negative frequency dependence of oscillatory resistance existed in these children was investigated. Negative frequency dependence of resistance between 8 and 28 Hz was a common finding in all height categories. With increasing height, resistance decreased and reactance increased in all children. Below 140 cm of height, resistance values at 8 Hz were higher, and reactance values at 8 Hz were more negative in girls than in boys. At heights above 140 cm the reverse was found. Resonant frequency was found to be higher in boys than in girls. The incidence of negative frequency dependence of resistance (FD) decreases during growth. Over heights of 130-160 cm, more negative FD existed in boys than in girls. It can be concluded that negative FD between 8 and 28 Hz can be found in healthy children up to 12 years of age, most pronounced in boys, not necessarily implicating pulmonary pathology.