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Normal values for forced oscillatory respiratory resistance in children
Insights
This study establishes normal respiratory resistance values for children using a quadratic regression model. Results suggest FEV1 is a more sensitive indicator of bronchial obstruction than forced oscillatory resistance in pediatric patients.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Assessing respiratory resistance in children is crucial for diagnosing and managing lung diseases.
- Existing methods may have limitations in accuracy and applicability to young children.
Purpose of the Study:
- To establish normative data for forced oscillatory respiratory resistance in healthy children.
- To evaluate the predictive accuracy of different regression models for respiratory resistance.
- To compare the sensitivity of forced oscillatory respiratory resistance with FEV1 in detecting mild bronchial obstruction.
Main Methods:
- Measured forced oscillatory respiratory resistance in 138 healthy children (aged 2-16 years) using a commercial device.
- Performed regression analysis using height as the independent variable to predict normal resistance values.
- Calculated coefficients of variation (CV) to assess measurement reproducibility.
- Compared resistance values in children with mild asthma to established normal ranges.
Main Results:
- A quadratic regression model using height provided the best prediction of normal respiratory resistance and its range.
- Average individual coefficients of variation for resistance parameters were 9-13%, suggesting an expected CV of ~10% for repeated measurements.
- Most children with mild asthma fell within the normal reference intervals for respiratory resistance, indicating FEV1 may be more sensitive to obstruction.
Conclusions:
- Height-based quadratic regression effectively predicts normal respiratory resistance in children.
- Forced oscillatory respiratory resistance demonstrates good reproducibility with an expected CV of 10%.
- FEV1 appears more sensitive than forced oscillatory resistance for detecting mild bronchial obstruction in pediatric populations.
- This method is applicable for evaluating young children, monitoring individual patients, and in bronchodilation/challenge testing.
Abstract:
Forced oscillatory respiratory resistance was measured in 138 healthy children aged 2- to 16-years-old using a commercial unit. Regression analysis was performed using the resistance measurements obtained at frequencies of 6 Hz and 26 Hz and averages of measurements obtained at frequencies of from 6-26 Hz, 6-10 Hz, and 22-26 Hz. The analysis suggested that regression curves and 95% confidence intervals obtained using a quadratic model with height as the independent variable provided the best prediction of normal values and their ranges. Three independent sets of resistance measurements, which were obtained for all 138 subjects, were used to calculate the average individual coefficients of variation (CV) for the five resistance parameters noted above; these ranged from 9 to 13%. This analysis suggested that the expected CV of repeated measurements would be about 10%. Finally, values from 13 children who had asthma with mild bronchial obstruction (FEV1 less than 80% of predicted) were compared with the normal values derived from the regression curves. Values from all but two of the children fell within the reference intervals, suggesting that FEV1 may be a more sensitive measure of obstruction than forced oscillatory resistance. The main applications of this new approach may be in the evaluation of young children, in following individual patients, and in bronchodilation and bronchial challenge tests.