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Updated: Jul 17, 2026
Employing the Forced Oscillation Technique for the Assessment of Respiratory Mechanics in Adults
Published on: February 9, 2022
Respiratory function in healthy young children using forced oscillations
Graham L Hall1, Peter D Sly, Takayoshi Fukushima
1Respiratory Medicine, Princess Margaret Hospital for Children, and School of Paediatric and Child Health, University of Western Australia, Perth, 6840 Australia. graham.hall@health.wa.gov.au
Insights
This study establishes reference ranges for respiratory function in healthy children aged two to seven years using the forced oscillation technique. The findings demonstrate good repeatability, aiding in the diagnosis and management of pediatric respiratory conditions.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Monitoring respiratory function is crucial for diagnosing and managing respiratory diseases.
- The forced oscillation technique (FOT) is ideal for assessing lung function in young children due to minimal cooperation requirements.
Purpose of the Study:
- To develop reference ranges for respiratory impedance variables in healthy children.
- To document the short-term repeatability of FOT measurements in this pediatric population.
Main Methods:
- FOT with a pseudo-random noise signal (4–48 Hz) was used to measure respiratory function in healthy children.
- Respiratory resistance (Rrs) and reactance (Xrs) were assessed at 6, 8, and 10 Hz.
- Repeatability was evaluated over a 15-minute period, and regression equations/Z-scores were determined.
Main Results:
- Data were collected from 158 healthy children (2–7 years old).
- Respiratory mechanics showed linear relationships with height.
- Within-test variability was 6–9% for resistance and 17–20% for reactance; no significant changes were observed over 15 minutes.
Conclusions:
- Reference ranges for respiratory impedance variables in healthy children (2–7 years) are provided.
- The study reports the short-term repeatability of FOT variables in this age group.
- These data enable the definition of appropriate cut-off values for therapeutic interventions.
Background:
Monitoring of respiratory function is important in the diagnosis and management of respiratory disease. The forced oscillation technique requires minimal patient cooperation and is ideal for the determination of respiratory function in young children. This study aimed to develop reference ranges and to document the repeatability in healthy young children using commercially available forced oscillation equipment.
Methods:
The forced oscillation technique, which uses a pseudo-random noise forcing signal between 4 and 48 Hz, was used to measure respiratory function in healthy young children. Repeatability over a 15 min period was also assessed. Regression equations and standardised Z scores were determined for respiratory resistance (Rrs) and reactance (Xrs) at 6, 8 and 10 Hz.
Results:
Respiratory function was obtained in 158 healthy children aged two to seven years and between 92 and 127 cm in height. Oscillatory respiratory mechanics exhibited linear relationships with height. Within-test variability for resistance ranged between 6% and 9% and between 17% and 20% for reactance. Resistance and reactance did not change significantly over a 15 min period.
Conclusions:
Reference ranges for respiratory impedance variables in healthy children aged two to seven years are presented. The short-term repeatability of forced oscillatory variables in this age group is reported, allowing appropriate cut-off values for therapeutic interventions to be defined.
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