Pulmonary Diffusing Capacity During Postural Postural Changes and Acute Exercise

Study Overview
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Brief Summary
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The combined measurement of the pulmonary diffusing capacity to carbon monoxide (CO) and nitric oxide (NO) (DLCO/NO) has recently been standardised and validated for clinical use. It involves a very short breath-hold time (≤5 seconds), and it may be repeated up to 12 times without affecting measurements, and it is thus ideal for assessing acute changes in pulmonary diffusing capacity and its components during various physiological manoeuvres. The aim of the present study is to compare the test-retest reliability of pulmonary diffusing capacity measurements during postural changes (sitting vs. supine) vs. rest-to-exercise. DLCO/NO will either be measured in the sitting position during rest vs. exercise or in the sitting and supine posture, and this will be repeated within 1-7 days in 20 healthy individuals that will be randomised to one of the two interventions. Statistically,the test-retest relaibility of sitting-to-supine vs. rest-to-exercise changes in DLCO/NO will be compared by parametric methods.

Official Title
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Pulmonary Diffusing Capacity Changes to Posture and Acute Exercise in Healthy Volunteers: a Randomised Test-retest Relaibility Study

Conditions
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Clinical Assessments of Pulmonary Diffusing Capacity

Intervention / Treatment
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* Diagnostic Test: Rest-to-exercise
* Diagnostic Test: Sitting-to-supine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: • Regular exercise (1-3 timer per week) Exclusion Criteria: Any known medical condition that requires regular medication or any known lung condition Smoking Symptoms of disease within 2 weeks prior to the study Abnormal lung function test Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Randomised study
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Rest-to-exercise<br> | Diagnostic Test: Rest-to-exercise<br>* Pulmonary diffusing capacity is assessed at rest and during exercise (70% of VO2max on a bicycle ergometer)<br>|
| Experimental: Sitting-to-supine<br> | Diagnostic Test: Sitting-to-supine<br>* Pulmonary diffusing capacity is assessed in the sitting and supine position<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Between intervention DLNO/DLCO-ratio repeatability coefficient | Test-retest reliability coefficient of rest-to-exercise and supine-to-prone DLNO/DLCO-ratio | 1 week | 
| Between intervention DLCO repeatability coefficient | Test-retest repeatability coefficient of rest-to-exercise and supine-to-prone DLCO | 1 week | 
| Between intervention DLNO repeatability coefficient | Test-retest repeatability coefficient of rest-to-exercise and supine-to-prone DLNO | 1 week | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Between intervention DM repeatability coefficient | Test-retest repeatability coefficient of rest-to-exercise and supine-to-prone DM | 1 week | 
| Between intervention Vc repeatability coefficient | Test-retest repeatability coefficient of rest-to-exercise and supine-to-prone Vc | 1 week |