Using impulse oscillometry, multiple-breath nitrogen washout and exhaled nitric oxide together to assess asthma inflammation

Using impulse oscillometry, multiple-breath nitrogen washout and exhaled nitric oxide before and after salbutamol inhalation to determine the site and degree of airways inflammation in patients with asthma

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12619000287134

Enrollment

Registered

2019-02-26

Start date

2019-03-18

Completion date

2019-11-15

Last updated

2020-02-10

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

It has been argued that, because of the complex relationship between FENO and airway calibre, FENO should not be measured alone but should instead be integrated into an ‘inflammometer’ that comprises FENO measurement and physiological measurement of airways obstruction. Unfortunately, measures of small airways obstruction are not routinely used in clinical practice and this region of the lung has been described as the ‘silent zone’ as a consequence. Impulse oscillometry and multiple breath nitrogen washout are physiological tests that can measure variables related to small airways obstruction in a research setting and they have become more reliable and user-friendly in recent years. We intend to explore the relationship between FENO and measures of small airways obstruction in patients with asthma. In particular, the relationship between FENO and measures related to small airways obstruction using impulse oscillometry has not previously been examined. This is important because, like FENO, impulse oscillometry is a simple, easy test for patients. If we could determine a relationship between FENO and measures obtained from impulse oscillometry, it might ultimately be possible to integrate the two into an ‘inflammometer’ that could be used clinically. In this study, we will test the hypothesis that, in the presence of a stable airway inflammatory state, there is a relationship between baseline physiological measures of small airways obstruction and the change in FENO on subsequent bronchodilation with inhaled ß2-agonist. We will recruit 40 participants with physician-diagnosed asthma. They will be asked to withhold short-acting inhaled asthma treatment for 6 hours and long-acting inhaled asthma treatment for 12-24 hours prior to a single visit to the Otago Respiratory Research Unit. At that visit, we will obtain informed consent, collect demographic data from participants and they will complete an asthma control questionnaire. Then impulse oscillometry, FENO measurement, multiple breath nitrogen washout and spirometry will be undertaken (1) at baseline and (2) after inhaled ß2-agonist therapy (bronchodilation).

Interventions

One dose of inhaled salbutamol (600mcg) given by research staff via metered-dose inhaler (with spacer) over 10 minutes at one study visit.

Study design

Allocation

Non-randomised trial

Intervention model

Single group

Primary purpose

Diagnosis

Masking

Open (masking not used)

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

Physician-diagnosed asthma requiring a minimum of treatment with regular inhaled corticosteroid.

Exclusion criteria

Diagnosis of COPD, bronchiectasis, lung cancer. Other co-morbidity likely to affect study participation. Current smoker (any cigarette smoking within past two months). Previous ICU admission for acute asthma.

Outcome results