Normal limits for oscillometric bronchodilator responses and relationships with clinical factors

Kanika Jetmalani¹, Nathan J Brown^{1

2}, Chantale Boustany^{1

3}, Brett G Toelle^{1

4}, Guy B Marks^{1

5

6}, Michael J Abramson⁷, David P Johns⁸, Alan L James^{9

10

11}, Michael Hunter^{9

12}, Arthur W Musk^{9

10}, Norbert Berend¹, Claude S Farah^{1

13}, David G Chapman^{1

14}, Cindy Thamrin¹, Gregory G King^{1

4}

Affiliations

¹ The Woolcock Institute of Medical Research, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
² Royal Brisbane and Women's Hospital, Emergency and Trauma Centre, Herston, QLD, Australia.
³ School of Nursing, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
⁴ Sydney Local Health District, Sydney, NSW, Australia.
⁵ South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia.
⁶ Ingham Institute of Applied Medical Research, Sydney, NSW, Australia.
⁷ School of Population Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
⁸ College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia.
⁹ Busselton Population Medical Research Institute, Busselton, WA, Australia.
¹⁰ School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia.
¹¹ Dept of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia.
¹² School of Population and Global Health, University of Western Australia, Perth, WA, Australia.
¹³ Dept of Thoracic Medicine, Concord Repatriation General Hospital, Sydney, NSW, Australia.
¹⁴ Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.

PMID: 34761000
PMCID: PMC8573235
DOI: 10.1183/23120541.00439-2021

Normal limits for oscillometric bronchodilator responses and relationships with clinical factors

Kanika Jetmalani et al. ERJ Open Res. 2021.

. 2021 Nov 8;7(4):00439-2021.

doi: 10.1183/23120541.00439-2021. eCollection 2021 Oct.

Authors

Affiliations

¹ The Woolcock Institute of Medical Research, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
² Royal Brisbane and Women's Hospital, Emergency and Trauma Centre, Herston, QLD, Australia.
³ School of Nursing, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
⁴ Sydney Local Health District, Sydney, NSW, Australia.
⁵ South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia.
⁶ Ingham Institute of Applied Medical Research, Sydney, NSW, Australia.
⁷ School of Population Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia.
⁸ College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia.
⁹ Busselton Population Medical Research Institute, Busselton, WA, Australia.
¹⁰ School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia.
¹¹ Dept of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia.
¹² School of Population and Global Health, University of Western Australia, Perth, WA, Australia.
¹³ Dept of Thoracic Medicine, Concord Repatriation General Hospital, Sydney, NSW, Australia.
¹⁴ Dept of Respiratory Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.

PMID: 34761000
PMCID: PMC8573235
DOI: 10.1183/23120541.00439-2021

Abstract

Introduction: We aimed to determine normal thresholds for positive bronchodilator responses for oscillometry in an Australian general population sample aged ≥40 years, to guide clinical interpretation. We also examined relationships between bronchodilator responses and respiratory symptoms, asthma diagnosis, smoking and baseline lung function.

Methods: Subjects recruited from Sydney, Melbourne and Busselton, Australia, underwent measurements of spirometry, resistance (R _rs₆ ) and reactance (X _rs₆ ) at 6 Hz, before and after inhalation of salbutamol 200 μg. Respiratory symptoms and/or medication use, asthma diagnosis, and smoking were recorded. Threshold bronchodilator responses were defined as the fifth percentile of decrease in R _rs₆ and 95th percentile increase in X _rs₆ in a healthy subgroup.

Results: Of 1318 participants, 1145 (570 female) were analysed. The lower threshold for ΔR _rs₆ was -1.38 cmH₂O·s·L^-1 (-30.0% or -1.42 Z-scores) and upper threshold for ΔX _rs₆ was 0.57 cmH₂O·s·L^-1 (1.36 Z-scores). Respiratory symptoms and/or medication use, asthma diagnosis, and smoking all predicted bronchodilator response, as did baseline oscillometry and spirometry. When categorised into clinically relevant groups according to those predictors, ΔX _rs₆ was more sensitive than spirometry in smokers without current asthma or chronic obstructive pulmonary disease (COPD), ∼20% having a positive response. Using absolute or Z-score change provided similar prevalences of responsiveness, except in COPD, in which responsiveness measured by absolute change was twice that for Z-score.

Discussion: This study describes normative thresholds for bronchodilator responses in oscillometry parameters, including intra-breath parameters, as determined by absolute, relative and Z-score changes. Positive bronchodilator response by oscillometry correlated with clinical factors and baseline function, which may inform the clinical interpretation of oscillometry.

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Conflict of interest statement

Conflict of interest: K. Jetmalani is a part-time employee of GlaxoSmithKline. Conflict of interest: N.J. Brown has nothing to disclose. Conflict of interest: C. Boustany has nothing to disclose. Conflict of interest: B.G. Toelle has nothing to disclose. Conflict of interest: G.B. Marks has nothing to disclose. Conflict of interest: M.J. Abramson reports an investigator-initiated grant to conduct the BOLD study in Australia from the National Health and Medical Research Council during the conduct of the study; and investigator-initiated grants for unrelated research from Pfizer and Boehringer Ingelheim, personal fees for unrelated consultancies and assistance with congress attendance from Sanofi, and a speaker's fee from GlaxoSmithKline, outside the submitted work. Conflict of interest: D.P. Johns has nothing to disclose. Conflict of interest: A.L. James has nothing to disclose. Conflict of interest: M. Hunter has nothing to disclose. Conflict of interest: A.W. Musk has nothing to disclose. Conflict of interest: N. Berend is a part-time employee of GlaxoSmithKline. Conflict of interest: C.S. Farah has nothing to disclose. Conflict of interest: D.G. Chapman has nothing to disclose. Conflict of interest: C. Thamrin has a patent WO 2006130922 A1 issued, which is broadly relevant to the work. In addition, she has intellectual property arrangements with Thorasys, Thoracic Medical Systems and Restech srl relating to research collaborations, but does not have any financial relationships with either company. Conflict of interest: G.G. King reports intellectual property arrangements covering research collaborations and provision of FOT devices for research from Restech during the conduct of the study; fees for consultancy services (which include lectures and advisory board services), conference attendance support and unrestricted research grants from AstraZeneca, Boehringer Ingelheim, CycloPharm, GlaxoSmithKline, Novartis, Menarini and MundiPharma, and research grants and fellowships from the National Health and Medical Research Council, the Asthma Foundation and philanthropic donations via Sydney University, outside the submitted work.

Figures

**FIGURE 1**
The bronchodilator-induced changes in a) resistance and b) reactance parameters of the respiratory system, for each of the clinically defined groups. BDR: bronchodilator response; Δ: post-bronchodilator minus pre-bronchodilator change; R_rs₆: resistance of the respiratory system measured at 6 Hz; insp: inspiratory; X_rs₆: reactance of the respiratory system measured at 6 Hz; EFLi: expiratory flow limitation index; Asym; asymptomatic: Symp: symptomatic.

**FIGURE 2**
Disposition into clinical groups. See Results section for definition of groups. Asym: asymptomatic; Symp: symptomatic.

See this image and copyright information in PMC

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Normal limits for oscillometric bronchodilator responses and relationships with clinical factors

Affiliations

Normal limits for oscillometric bronchodilator responses and relationships with clinical factors

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

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