This study aims to establish normative values for respiratory oscillometry in the Polish pediatric population. It is designed as a multicentre, population-based, prospective cohort study including children and adolescents aged 3-18 years. The results will provide reference standards for respiratory oscillometry that may support the diagnosis and monitoring of respiratory diseases in clinical practice and research.
OSCILLONiCA-PL-Kids is a multicentre, observational, cross-sectional study designed to establish normative reference values for respiratory oscillometry (IOS) in healthy Polish children and adolescents aged 3-18 years. The study is coordinated by the Polish Society of Pediatric Pulmonology and conducted in 12 pediatric centers across Poland between 2023 and 2025. Standardized Jaeger oscillometry systems (ERS-validated) are used across all sites, following harmonized operating procedures. All investigators and technicians undergo centralized training and certification, with periodic audits and refresher sessions to ensure procedural consistency and data quality. Measurements are performed during tidal breathing with cheek support and a nose clip, recording at least three technically acceptable trials per participant. Parameters include resistance (Rrs) and reactance (Xrs) at 5, 10, and 20 Hz, resonance frequency (Fres), and area of reactance (AX). Anthropometric data (height, weight, age, sex) are collected simultaneously to allow modeling of predicted values. Data integrity is verified using automated quality-control algorithms. Reference equations for oscillometric parameters will be derived using generalized additive models for location, scale, and shape (GAMLSS, LMS method). Model performance will be evaluated using the Schwarz Bayesian Criterion, with sensitivity analyses assessing robustness to borderline cases and environmental exposures. Raw measurement data, as well as derived parameters (means, standard deviations, percentiles, and z-scores), will be used to generate normative reference values and percentile charts stratified by age, height, and sex. Quality assurance: Data collection and management follow standardized operating procedures (SOPs) approved by the coordinating center. Each site conducts internal data validation prior to upload, and periodic cross-site audits are performed to ensure compliance and consistency. Automatic range and logic checks are implemented in the database to flag out-of-range or inconsistent entries. Missing data plan: Incomplete or invalid recordings will be excluded from normative modeling. Sensitivity analyses will evaluate the impact of missing data on reference equations. Imputation will not be used for normative dataset derivation. The study adheres to ERS Technical Standards for Oscillometry (2020) and complies with Good Clinical Practice for observational research. The resulting reference equations and percentile charts will provide validated normative standards for pediatric oscillometry in Poland and support future international harmonization efforts.
Study Type
OBSERVATIONAL
Enrollment
2,000
Medical University of Gdańsk
Gdansk, Gdańsk, Poland
Reference values and z-score distributions for respiratory oscillometry parameters (Rrs, Xrs, Fres, AX) in healthy Polish children and adolescents
Quantitative reference data for respiratory oscillometry parameters - respiratory resistance (Rrs) and reactance (Xrs) at 5, 10, and 20 Hz, resonance frequency (Fres), and area of reactance (AX) - measured using impulse oscillometry (IOS) in healthy children and adolescents aged 3-18 years. Results will be summarized as mean (Units of Measure: Rrs, Xrs: kPa·s·L-¹; Fres: Hz; AX: kPa·L-¹); standard deviation (SD), percentiles, and z-score distributions stratified by age, height, and sex.
Time frame: Single assessment at baseline (during one study visit).
Prediction equations and z-score reference models for oscillometric parameters (Rrs, Xrs, Fres, AX)
Regression models describing the relationship between oscillometric parameters (Rrs, Xrs, Fres, AX) and anthropometric predictors (age, height, weight, sex). Models will be developed using the Generalized Additive Models for Location, Scale, and Shape (GAMLSS; LMS method). Predicted means, SDs, and z-score equations will be reported, together with model coefficients, standard errors, and model fit indices (Schwarz Bayesian Criterion). Units of Measure: Model coefficients (unitless); Rrs, Xrs: kPa·s·L-¹; Fres: Hz; AX: kPa·L-¹; z-scores: dimensionless
Time frame: At baseline (single study visit).
Variability of respiratory oscillometry parameters (Rrs, Xrs, Fres, AX) across pediatric age groups
Mean and standard deviation of oscillometry parameters - respiratory resistance (Rrs, kPa·s·L-¹), reactance (Xrs, kPa·s·L-¹), resonance frequency (Fres, Hz), and area of reactance (AX, kPa·L-¹) - compared across three predefined pediatric age groups: preschool (3-5 years), school-aged (6-12 years), and adolescents (13-18 years). All parameters will also be expressed as z-scores (dimensionless) for standardized inter-group comparison.Units of Measure: Rrs, Xrs: kPa·s·L-¹; Fres: Hz; AX: kPa·L-¹; z-scores: dimensionless.
Time frame: At baseline (single study visit).
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Z-score distributions for oscillometry parameters across Polish and international pediatric cohorts
Z-score distributions for respiratory resistance (Rrs), reactance (Xrs), resonance frequency (Fres), and area of reactance (AX) derived from the OSCILLONiCA-KIDS dataset and published international reference datasets (Austria). Differences between cohorts will be summarized as mean z-score differences and limits of agreement.
Time frame: Up to 24 months after completion of data collection (estimated by December 2026).
Nomograms and percentile charts for clinical use
Nomograms and percentile charts illustrating predicted oscillometry parameters (Rrs, Xrs, Fres, AX) across age, height, and sex categories will be created to support clinical interpretation. Each chart will include mean, standard deviation (SD), percentiles (5th, 25th, 50th, 75th, 95th), and corresponding z-score ranges.Units of Measure: Rrs, Xrs: kPa·s·L-¹; Fres: Hz; AX: kPa·L-¹; z-scores: dimensionless
Time frame: Through study completion, approximately 36 months after study start (January 2023 - December 2025).
De-identified reference dataset of pediatric oscillometry measurements
A de-identified dataset containing oscillometry and anthropometric data (age, height, weight, sex, Rrs, Xrs, Fres, AX) will be compiled for research use and potential integration into international reference initiatives (e.g., Global Lung Function Initiative). Dataset records will be reported as counts of included participants and data completeness metrics. Units of Measure: Number of data records (n); data completeness (%)
Time frame: Through study completion, approximately 36 months after study start (January 2023 - December 2025).
Quality and performance indicators of school-based oscillometry testing
Proportion of technically acceptable recordings, coefficient of variation (CoV) between repeated trials, and proportion of children successfully completing valid measurements during school-based testing sessions. Units of Measure: Percentage of valid recordings (%); coefficient of variation (%)
Time frame: Throughout data collection, approximately January 2023 - June 2025.