Optimized Single-breath Helium Lung Volume in Obstructive Lung Disease

Study Overview
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Brief Summary
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Whole-body plethysmography (WBP) is the gold standard for measuring lung volume, but its clinical application is limited because it requires expensive equipment and is complicated to use. Studies have shown that the single-breath helium dilution (SBHD) method, which is commonly used in clinical practice, significantly underestimates lung volume in patients with obstructive lung disease (OLD). Therefore, by comparing the differences in lung volume measured by the SBHD method and WBP in patients with different severities of obstructive lung disease, we aim to establish a correction equation for the SBHD method to determine the total lung volume in obstructive lung disease patients.

Official Title
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Measurement of the Total Lung Volume Using Optimized Single-breath Helium Dilution Method in Patients With Obstructive Lung Disease

Conditions
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Obstructive Lung Disease

Intervention / Treatment
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* Diagnostic Test: the single-breath helium dilution method and Whole-body plethysmography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: (1) age 18-80 years and (2) in line with the ATS/ERS definition of obstructive lung disease. Exclusion Criteria: (1) contraindications for spirometry, pulmonary diffusion function test, and WBP and (2) history of lung surgery and recent history of chest trauma.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| modeling group<br>Of these 628 individuals, we set 407 patients enrolled from January 2018 to November 2019 as the modeling group | Diagnostic Test: the single-breath helium dilution method and Whole-body plethysmography<br>* The patients with obstructive lung disease simultaneously subjected to the single-breath helium dilution method and Whole-body plethysmography tests.<br>|
| verification cohort<br>221 patients enrolled from December 2019-December 2020 served as a prospective verification cohort | Diagnostic Test: the single-breath helium dilution method and Whole-body plethysmography<br>* The patients with obstructive lung disease simultaneously subjected to the single-breath helium dilution method and Whole-body plethysmography tests.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Establishment of the TLC-SBHD correction equation | TLC-adjusted SBHD (L) = -0.669 + 0.756 × TLC-SBHD (L) - 0.047 × FEV1/FVC + 0.039 × height (cm) - 0.009 × weight (kg) (r2 = 0.753 and adjusted r2 = 0.751) | 2 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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total lung capacity, obstructive lung disease, the single-breath helium dilution, Whole-body plethysmography, correction equation