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Breath Collection from Children for Disease Biomarker Discovery
Published on: February 14, 2019
Clinical investigation of respiratory system admittance in preschool children
Shannon J Simpson1, Sune P Straszek, Peter D Sly
1Centre for Child Health Research, Telethon Institute for Child Health Research, University of Western Australia, Perth, Western Australia, Australia.
Insights
Respiratory system admittance (Ars) shows promise for measuring airway challenges, particularly with inhaled adenosine-5'-monophosphate (AMP). However, Ars did not improve differentiation of bronchodilator responses in children with respiratory disease.
Area of Science:
- Pediatric Respiratory Medicine
- Pulmonary Function Testing
- Respiratory Physiology
Background:
- Upper airway shunting affects respiratory system impedance (Zrs) measurements, especially in children.
- Respiratory system admittance (Ars), the inverse of Zrs, is theoretically unaffected by shunting.
- This study investigates Ars as an alternative to standard outcomes for assessing respiratory disease and challenge responses.
Purpose of the Study:
- To compare the diagnostic ability of Ars versus standard forced oscillation technique (FOT) outcomes.
- To evaluate Ars's effectiveness in differentiating responses to inhaled adenosine-5'-monophosphate (AMP) and bronchodilators.
- To establish reference equations for Ars in healthy preschool children.
Main Methods:
- Utilized the forced oscillation technique (FOT) to measure respiratory system admittance (Ars).
- Established reference equations for Ars in healthy preschool children.
- Compared Ars and standard FOT outcomes during inhaled AMP and bronchodilator challenges in healthy children and those with respiratory disease.
Main Results:
- Children with respiratory disease exhibited lower baseline Ars compared to healthy children.
- Ars did not enhance the differentiation of bronchodilator responses between healthy and diseased populations.
- Inhaled AMP challenge responses were detected at lower concentrations using Ars compared to respiratory system resistance (Rrs).
Conclusions:
- Ars is a valuable tool for assessing responses to inhaled challenges like AMP.
- Ars is not recommended for evaluating bronchodilator responses in this context.
- Further research may explore Ars's utility in pediatric respiratory diagnostics.
Introduction:
The upper airway shunt attenuates measurements of respiratory system impedance (Zrs), with greater impact in young children. Changes in respiratory system admittance, Ars (or Zrs(-1)), are theoretically independent of the shunt. This study compared the ability of Ars, to standard oscillatory outcomes, to determine respiratory disease and differentiate responses to inhaled bronchial challenges in the clinical setting.
Methods:
The forced oscillation technique (FOT) was used to establish reference equations for Ars in healthy preschool children, compare the change in Ars to standard oscillatory outcomes during bronchial challenge with inhaled adenosine-5'-monophosphate (AMP) and to inhaled bronchodilator in healthy children and those with respiratory disease.
Results:
Children with respiratory disease had lower baseline Ars than healthy children (P < 0.05). However, there was no improved ability for Ars to differentiate between bronchodilator responses in healthy and disease populations. In contrast, the response to inhaled AMP occurred at a lower concentration, [25 (3.12-400) mg ml(-1); median (10th-90th centile)], as measured by Ars when compared to respiratory system resistance [225 (6.25-400) mg ml(-1); P = 0.016].
Conclusion:
This study supports the use of Ars during inhaled challenges, but not in response to bronchodilation.
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