Clinical trial NCT06509659: Methacholine Challenge Test (MCT) in Healthy Adults
Official title: Methacholine Challenge Test (MCT) in Healthy Adults: Oscillometry Measured Alone Compared to Oscillometry and FEV1 During the Same Test
Study type: OBSERVATIONAL
Overall status: RECRUITING
Conditions: Hyperreactive Airway Disease
Keywords: IOS
oscillometry
spirometry
bronchial hyperreactivity
Lead sponsor: Allergi- og Lungeklinikken, Elsinore
Sponsor class: NETWORK
First posted: 2024-07-19
Enrollment: 25
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_ONLY
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Healthy adults

Brief summary: Knowledge of Methacholine Challenge Test (MCT) and impedance Oscillometry (IOS) is limited. Only three studies have included adult patients, and none of these with healthy controls. The three studies have combined IOS and spirometry in the same test, although it is not recommended to perform IOS after a test that requires deep breathing, e.g. FEV1 measurement. Deep breathing is considered to affect the impedance via reduced tone in the smooth muscle.

Detailed description: Asthma is a common chronic disease that is characterized by a history of variable respiratory symptoms and variable expiratory airflow limitation, and usually associated with airway hyperresponsiveness.

In general, FEV1 is used to test for airway hyperresponsiveness (AHR), and a 20% decrease after methacholine challenge test (MCT) is considered a positive test.

There is increasing recognition that the small airways are involved in 40-80% of patients with asthma, and the function of these airways is overlooked (the "silent zone") when measuring FEV1, which mainly reflects the function of the central airways.

Small airway dysfunction (SAD) can be assessed by IOS where pressure applied to the airways at a range of frequencies, and components of respiratory resistance and reactance are measured. Resistance at 5 Hz (R5) and 20 Hz (R20), respectively, represent total airway resistance and proximal airway resistance. The difference between these two values can be calculated (R5-R20). High R5-R20 and low reactance at 5 Hz (X5) indicate the presence of SAD.

Knowledge of MCT and IOS is limited. Only three studies have included adult patients, and none of these with healthy controls. These studies have combined IOS and spirometry in the same test, although it is not recommended to perform IOS after a test that requires deep breathing, e.g. FEV1 measurement. Deep breathing is considered to affect the impedance via reduced tone in the smooth muscle.

The investigators have the following objectives for these studies:

1. To determine the IOS response to MCT in healthy adults.
2. To investigate whether spirometry (FEV1) carried out in relation to MCT influences IOS by comparing the IOS response to MCT performed with and without spirometry in healthy adults.

Eligibility criteria: Inclusion Criteria:

* Forced expiratory volume in the 1. second (FEV1) \>80%
* FEV1/FVC-ratio \>0,7
* FeNO \<25 pbb
* Oxygen saturation (SatO2) \>95%
* Negative methacholine Challenge Test = drop in FEV1 less than 20%

Exclusion Criteria:

* Any lung disease
* Lung symptoms
* Medicine for lung disease
* Tobacco smoking
* Ex-smokers with more than 5 package years
* BMI (body mass index) \>40 kg/m2

Primary outcomes:
measure: Oscillometry; R5
timeFrame: baseline (carried out with FEV1 measurement)
measure: Oscillometry; R5
timeFrame: 1-10 days from baseline and carried out without FEV1 measurement
measure: Oscillometry; R20
timeFrame: baseline (carried out without FEV1 measurement)
measure: Oscillometry; R20
timeFrame: 1-10 days from baseline and carried out without FEV1 measurement
measure: Oscillometry; X5
timeFrame: baseline (carried out without FEV1 measurement)
measure: Oscillometry; X5
timeFrame: 1-10 days from baseline and carried out without FEV1 measurement
measure: Oscillometry; AX
timeFrame: baseline (carried out without FEV1 measurement)
measure: Oscillometry; AX
timeFrame: 1-10 days from baseline and carried out without FEV1 measurement
measure: Oscillometry; Fres
timeFrame: baseline (carried out without FEV1 measurement)
measure: Oscillometry; Fres
timeFrame: 1-10 days from baseline and carried out without FEV1 measurement
Secondary outcomes:
Other outcomes:
Locations:
city: Helsingør
country: Denmark
facility: Thomas Ringbæk
Study officials:
affiliation: Allergy and Lung Clinic Elsinore
name: Thomas J Ringbæk
role: PRINCIPAL_INVESTIGATOR
References:
citation: Coates AL, Wanger J, Cockcroft DW, Culver BH; Bronchoprovocation Testing Task Force: Kai-Hakon Carlsen; Diamant Z, Gauvreau G, Hall GL, Hallstrand TS, Horvath I, de Jongh FHC, Joos G, Kaminsky DA, Laube BL, Leuppi JD, Sterk PJ. ERS technical standard on bronchial challenge testing: general considerations and performance of methacholine challenge tests. Eur Respir J. 2017 May 1;49(5):1601526. doi: 10.1183/13993003.01526-2016. Print 2017 May.
citation: Cottini M, Lombardi C, Passalacqua G, Bagnasco D, Berti A, Comberiati P, Imeri G, Landi M, Heffler E. Small Airways: The "Silent Zone" of 2021 GINA Report? Front Med (Lausanne). 2022 May 23;9:884679. doi: 10.3389/fmed.2022.884679. eCollection 2022.