Dataset Information

Methacholine Challenge Testing: Comparison of FEV₁ and Airway Resistance Parameters.

ABSTRACT:

Background

A 20% reduction in the FEV₁ is routinely used as an end point for methacholine challenge testing (MCT). Measurement of FEV₁ is effort dependent, and some patients are not able to perform acceptable and repeatable forced expiration maneuvers. The goal of the present study was to investigate the diagnostic value of airway resistance measurement by forced oscillation technique (FOT), body plethysmography, and interrupter technique compared with the traditionally accepted standard FEV₁ measurement in evaluating the responsiveness to methacholine during MCT.

Methods

We included in the study adult subjects referred for MCT because of asthma-like symptoms and with normal baseline spirometry. We modified routine MCT protocol by adding the assessment of airway resistance to the measurement of FEV₁ at each step of MCT.

Results

We observed, in the subjects with airway hyper-responsiveness versus those with normal airway responsiveness, a significantly greater percentage change in median (interquartile range) FOT resistance at 10 Hz (25.9% [13.7%-35.4%] vs 16% [15.7%-27.2%]), plethysmographic resistance (70.2% [39.5%-116.3%] vs 37.1% [23.9%-81.9%]), and mean ± SD conductance (-41.3 ± 15.4% vs -29.6 ± 15.9%); and a significantly greater change in mean ± SD FOT reactance at 10 Hz (-0.41 ± 0.48 cm H₂O/L/s vs -0.09 ± 0.32 cm H₂O/L/s) and at 15 Hz (-0.29 ± 0.2 cm H₂O/L/s vs -0.1 ± 0.19 cm H₂O/L/s). We also recorded significant differences in airway resistance parameters (FOT resistance at 10 Hz, FOT reactance at 15 Hz, plethysmographic airway resistance, and conductance indices as well as interrupter resistance) in FEV₁ non-responders at the onset of respiratory symptoms during MCT compared with baseline.

Conclusions

Measurements of airway resistance could possibly be used as an alternative method to spirometry in airway challenge. Significant changes in airway mechanics during MCT are detectable by airway resistance measurement in FEV₁ non-responders with methacholine-induced asthma-like symptoms. (ClinicalTrials.gov registration NCT02343419.).

SUBMITTER: Urbankowski T

PROVIDER: S-EPMC9994076 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Publications

Methacholine Challenge Testing: Comparison of FEV<sub>1</sub> and Airway Resistance Parameters.

Urbankowski Tomasz T Przybyłowski Tadeusz T

Respiratory care 20201117 3

<h4>Background</h4>A 20% reduction in the FEV<sub>1</sub> is routinely used as an end point for methacholine challenge testing (MCT). Measurement of FEV<sub>1</sub> is effort dependent, and some patients are not able to perform acceptable and repeatable forced expiration maneuvers. The goal of the present study was to investigate the diagnostic value of airway resistance measurement by forced oscillation technique (FOT), body plethysmography, and interrupter technique compared with the tradition ...[more]

PMID: 33203723

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Project description:BackgroundSmall airways are known to be affected early in the course of COPD; however, traditional spirometric indices may not accurately identify small airways disease.Research questionCan forced expiratory volume in 3 s/forced expiratory volume in 6 s (FEV3/FEV6) identify early airflow abnormalities and predict future clinically important respiratory-related outcomes, including development of COPD?Study design and methodsThe study included 832 current and former smokers with post-bronchodilator FEV1/FVC ≥ 0.7 from the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) cohort. Participants were classified as having a reduced pre-bronchodilator FEV3/FEV6 based on lower limit of normal (LLN) values. Repeatability analysis was performed for FEV3 and FEV6. Regression modeling was used to evaluate the relationship between baseline FEV3/FEV6 and outcome measures, including functional small airways disease, on thoracic imaging and respiratory exacerbations. Interval-censored analysis was used to assess progression to COPD.ResultsFEV3/FEV6 less than the LLN at baseline, defined as reduced compared with FEV3/FEV6 at or above the LLN, was associated with lower FEV1, poorer health status (St. George's Respiratory Questionnaire score), more emphysema, and more functional small airways disease on quantitative imaging. FEV3 and FEV6 showed excellent agreement between repeat measurements. A reduced FEV3/FEV6 was associated with increased odds of a severe respiratory exacerbation within the first year of follow-up and decreased time to first exacerbation. A low FEV3/FEV6 was also associated with development of COPD according to spirometry results (post-bronchodilator FEV1/FVC < 0.7) during study follow-up.InterpretationFEV3/FEV6 is a routinely available and repeatable spirometric index that can be useful in the evaluation of early airflow obstruction in current and former smokers without COPD. A reduced FEV3/FEV6 can identify those at risk for future development of COPD and respiratory exacerbations.Clinical trial registrationClinicalTrials.gov; No.: NCT01969344; URL: www.Clinicaltrialsgov: ClinicalTrials.gov.

Project description:Rationale: According to the Global Initiative for Obstructive Lung Disease (GOLD), the FEV1/FVC ratio is used to confirm the presence of airflow obstruction in the diagnosis of chronic obstructive pulmonary disease (COPD), whereas FEV1 percent predicted normal value (FEV1%pred) is used for grading its severity. The STaging of Airflow obstruction by the FEV1/FVC Ratio (STAR), and its prediction of adverse outcomes, has not been evaluated in general populations. Objectives: To compare the STAR (FEV1/FVC) and the GOLD (FEV1%pred) classifications for the severity of airflow limitation in terms of exertional breathlessness and mortality in the general U.S. population. Methods: Severity stages according to the STAR and GOLD were applied to the multiethnic National Health and Nutrition Examination Survey of 2007-2012, including people ages 18-80 years, using a postbronchodilatory FEV1/FVC ratio of <0.70 to define airflow obstruction in both staging systems. Prevalence of the severity stages STAR 1-4 and GOLD 1-4 was calculated, and associations with breathlessness and mortality were analyzed by multinomial logistic regression and Cox regression, respectively. Measurements and Main Results: STAR versus GOLD severity staging of airflow obstruction showed similar associations with breathlessness and all-cause mortality, regardless of ethnicity and/or race. In those with airflow obstruction, the correlation between the two classification systems was 0.461 (P < 0.001). STAR reclassified 59% of GOLD 2 subjects as having mild airflow obstruction (STAR 1). Compared with GOLD 1, STAR 1 was more clearly differentiated from nonobstruction in terms of both breathlessness and mortality. Conclusions: FEV1/FVC and FEV1%pred as measures of airflow limitation severity show similar predictions of breathlessness and mortality in the adult U.S. population across ethnicity groups. However, Stage 1 differed more clearly from nonobstruction on the basis of FEV1/FVC ratio than FEV1%pred.

Dataset Information

Methacholine Challenge Testing: Comparison of FEV₁ and Airway Resistance Parameters.

Background

Methods

Results

Conclusions

Publications

Methacholine Challenge Testing: Comparison of FEV<sub>1</sub> and Airway Resistance Parameters.

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OmicsDI is part of the ELIXIR infrastructure

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Dataset Information

Methacholine Challenge Testing: Comparison of FEV1 and Airway Resistance Parameters.

Background

Methods

Results

Conclusions

Publications

Methacholine Challenge Testing: Comparison of FEV<sub>1</sub> and Airway Resistance Parameters.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Methacholine Challenge Testing: Comparison of FEV₁ and Airway Resistance Parameters.