The Effect of Spontaneous Respiration on Pulse-oximetry Measurements

Study Overview
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Brief Summary
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This is a study designed to measure, characterize and describe changes on pulse-oxymetry values produced as a result of deep breaths in patients with stable chronic hypoxemic respiratory failure.

Detailed Description
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There is no standard way of measuring rest pulse-oxymetry in terms of depth of respiration. Rest pulse-oxymetry values are used in the clinical setting to make therapeutic decisions regarding the need of supplemental oxygen. The primary goal of this study is to measure the change of pulse-oxymetry values during an experimental protocol of 10 deep breaths during one minute in patients with chronic hypoxemia. 45 patients will be studied in this first phase. In a second phase, secondary goals will be to measure Vd/Vt vent, noninvasive cardiac output and CT densitometry during the same deep breaths protocol in a subset of 13 patients with the grater increase observed in the first phase of study.

Official Title
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The Effect of Spontaneous Respiration on Pulse-oximetry Measurements and Analysis of Variability Mechanisms

Conditions
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Chronic Respiratory Disease, COPD, Interstitial Lung Disease

Intervention / Treatment
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* Procedure: Deep breaths


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with chronic lung disease causing rest hypoxemia, with rest SpO2 values equal or lower than 94% on room air Ambulatory patients capable of performing 6 min walking test Patients older than 18 years old. Exclusion Criteria: Patients with significant collagen disease causing Raynaud phenomenon. Patients with hypothermia lower than 35 degrees Celsius Patients with rest SpO2 values equal or lower than 80% on room air Patients unable to perform PFTs Patients unable to complete 6 min walking test without supp O2. Patients unable to perform experimental deep breaths on CT scan

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Interventional Model Description: Clinical experimental trial of changes in pulse-oxymetry measurements with deep inspirations
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Patients with rest O2 desaturation<br>Patient will undergo an experimental protocol consisting of 10 deep inspirations to measure and characterize changes on pulse-oxymetry values | Procedure: Deep breaths<br>* Patients will undergo a 6 minutes protocol. Baseline: 1 minute normal breaths. Intervention: 1 minute with 10 deep breaths, 1 each 6 secs. Pulse-oxymetry will be continuously recorded.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in O2 saturation | A Saturation change greater than 4% will be considered significant | Lenght of experimental protocol: 6 minutes. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vd/VT | In a subset of 13 patients with the greater increase on O2Sat, Vd/Vt will be measured during the same protocol | Lenght of experimental protocol: 6 minutes. | 
| Cardiac output (CO) | In a subset of 13 patients with the greater increase on O2Sat, CO will be measured during the same protocol | Lenght of experimental protocol: 6 minutes. | 
| CT recruitment | In a subset of 13 patients with the greater increase on O2Sat, CT recruitment will be calculated using densitometry values during the same protocol | Lenght of experimental protocol: 6 minutes. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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pulseoxymetry, capnography, Dead space, cardiac output, lung recruitment, deep breaths