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Conducting Respiratory Oscillometry in an Outpatient Setting
Published on: April 8, 2022
Increased day-to-day variability of forced oscillatory resistance in poorly controlled or persistent pediatric asthma
Paul D Robinson1, Nathan J Brown2, Martin Turner2
1Woolcock Institute of Medical Research, Sydney; The University of Sydney, Sydney; Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead; Cooperative Research Centre for Asthma and Airways, Sydney.
Insights
Day-to-day variability in forced oscillation technique (FOT) respiratory resistance (Rrs) is increased in children with asthma and correlates with severity and control. FOT shows promise as an objective pediatric asthma monitoring tool.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Biomedical Engineering
Background:
- Pediatric asthma management requires sensitive, objective monitoring tools.
- The forced oscillation technique (FOT) is feasible for children, but its variability in relation to asthma control is not well understood.
Purpose of the Study:
- To investigate the relationship between day-to-day variability of FOT parameters (respiratory system resistance [Rrs] and respiratory system reactance [Xrs]) and asthma severity and control in children.
- To compare FOT variability in children with asthma to healthy children.
Main Methods:
- 22 children with asthma and 38 healthy children participated.
- Day-to-day variability of FOT Rrs and Xrs, and peak expiratory flow (PEF) were measured over 5 days in children with asthma.
- FOT variability was compared between asthma severity/control groups and with healthy controls.
Main Results:
- Increased day-to-day Rrs variability was observed in children with persistent and uncontrolled asthma compared to intermittent and partly controlled asthma, respectively.
- Day-to-day variability of Rrs and Xrs, but not baseline values, were significantly higher in children with asthma than in healthy controls.
- PEF variability did not distinguish between asthma groups.
Conclusions:
- Increased day-to-day FOT Rrs variability is a characteristic of pediatric asthma and is associated with asthma severity and control.
- FOT demonstrates potential as an objective tool for monitoring asthma in school-aged children.
- Further research is warranted to validate FOT's role in pediatric asthma management.
Background:
Pediatric asthma lacks sensitive objective measures for asthma monitoring. The forced oscillation technique (FOT) offers strong feasibility across the pediatric age range, but relationships between FOT parameter day-to-day variability and pediatric asthma severity and control are unknown.
Methods:
Day-to-day variability in FOT respiratory system resistance (Rrs) and respiratory system reactance (Xrs) compared with peak expiratory flow (PEF) were defined in 22 children with asthma (mean ± SD age, 10.4 ± 1.1 years) during a 5-day asthma camp. FOT was performed at 6 Hz in triplicate on each test occasion. Relationships between day-to-day FOT variability (expressed as within-subject SD [SDW] and asthma control and severity (defined according to GINA [Global Initiative for Asthma] recommendations) were explored. For comparison, normal baseline FOT values and variability, measured on two occasions, were defined in a separate cohort of 38 healthy children (age, 9.5 ± 1.0 years).
Results:
Day-to-day Rrs variability was greater in persistent (n = 16) vs intermittent (n = 6) asthma (mean SDW, 0.69 cm H2O/L/s vs 0.39 cm H2O/L/s; P ≤ .01). Day-to-day Rrs variability was increased in uncontrolled (n = 13) vs partly controlled asthma (n = 9) (mean SDW, 0.75 cm H2O/L/s vs 0.42 cm H2O/L/s; P ≤ .05). PEF variability did not differentiate the groups. Day-to-day variability of Rrs and Xrs but not baseline values were increased in children with asthma vs control children (Rrs mean SDW, 0.61 cm H2O/L/s vs 0.33 cm H2O/L/s [P ≤ .05]; Xrs mean SDW, 0.24 cm H2O/L/s vs 0.15 cm H2O/L/s [P ≤ .05]).
Conclusions:
Increased day-to-day FOT variability exists in school-aged children with asthma. Day-to-day Rrs variability was associated with asthma severity and asthma control. FOT may be a useful objective monitoring tool in pediatric asthma and warrants further study.
Trial Registry:
Australian and New Zealand Clinical Trials Registry; No.: ACTRN12614000885695; URL: www.anzctr.org.au.
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