Effects of an Auto-Regulating Oxygen System Compared to Constant-Flow Oxygen During Walking in Hypoxemic COPD Patients

Study Overview
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Brief Summary
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Oxygen therapy is a cornerstone in treating patients with severe chronic obstructive pulmonary disease. Usually, oxygen supplementation is delivered using constant-flow rates. Varying oxygenation levels may occur throughout patients´ changing activity. There is some evidence available that an auto-regulating oxygen flow system (FreeO2), which adjusts the oxygen flow automatically to prevent desoxygenation could be beneficial in comparison to a constant oxygen dose of 2 liter/min during walking. However, these possible benefits are unknown if the FreeO2 is compared to a constant oxygen dose according to the individual prescription. Therefore, the primary aim of this study is to investigate the effects of auto-regulated oxygen flow rates compared to constant oxygen flow rates as prescribed according to international guidelines on walking capacity in patients with COPD.

Detailed Description
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Rationale: Hypoxemia is frequently observed in COPD and thus can negatively impact exercise tolerance. Supplemental oxygen or long-term oxygen therapy is recommended to ensure that the patient is still able to manage his daily life. Usually, oxygen supplementation is delivered using constant flow rates during day- and nighttime or as needed. However, studies have shown, that auto-regulated oxygen flow systems (FreeO2) may enhance the patients endurance, lower the time in severe hypoxemia and increase the time spent within the SpO2 target range. Aim of this study is to investigate the effects off an auto-regulated oxygen flow system in hypoxemic COPD patients on the patient´s endurance, the oxygen saturation, the pCO2 blood level as well as on heart rate and breathing frequency compared to the effects off the prescribed constant flow (according to the British Thoracic Society Guidelines for Home Oxygen Use in Adults) during an endurance shuttle walk test (ESWT). Additionally, patients experience, e.g. comfort and Preference of the Oxygen-delivery System will be documented. Design: This study is a randomized, controlled cross-over trial. Following an initial incremental shuttle walk test (ISWT) in order to determine the participants individual maximal walking capacity, the participant will perform 2 endurance shuttle walk tests (ESWT) at 85% of the maximal walking rate. In randomized order, the participants will perform one ESWT with constant flow as prescribed and one ESWT with the auto-regulated oxygen flow system.

Official Title
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Effects of an Auto-Regulating Oxygen System Compared to Constant-Flow Oxygen During Walking in Hypoxemic COPD Patients - a Randomized Controlled Trial

Conditions
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COPD

Intervention / Treatment
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* Other: Oxygen therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: GOLD III/ IV Hypoxemia (PaO2<55 mmHg) under roomair conditions (rest or during exercise) or SpO2 <88% during exercise established Long-term oxygen therapy or given indication for a Long-term oxygen therapy Age: 40 to 80 years Participation in an inpatient pulmonary rehabilitation program (Schoen Klinik BGL, Germany) Written informed consent Exclusion Criteria: Acute Exacerbation of COPD Clinical signs of any acute cardiac comorbidity Not able to walk

Ages Eligible for Study
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Minimum Age: 40 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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ESWT Order A and B<br>First Endurance Shuttle walk test (A) with supplemental Oxygen therapy via auto-regulated oxygen flow rates (FreeO2) to maintain a oxygen saturation of 92% and second Endurance Shuttle walk (B) test with supplemental Oxygen therapy via constant oxygen flow rates | Other: Oxygen therapy<br>* Oxygen supply during ESWT, once with the prescribed constant oxygen flow and once using an auto-regulated oxygen flow system setting the SpO2 target at 92%.<br>|
| Experimental: ESWT Order B and A<br>First Endurance Shuttle walk test (B) with supplemental Oxygen therapy via constant oxygen flow rates and second Endurance Shuttle walk (A) test with supplemental Oxygen therapy via auto-regulated oxygen flow rates (FreeO2) to maintain a oxygen saturation of 92% | Other: Oxygen therapy<br>* Oxygen supply during ESWT, once with the prescribed constant oxygen flow and once using an auto-regulated oxygen flow system setting the SpO2 target at 92%.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endurance time | Change of Walking Duration during the ESWT | Day 1 and Day 2 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of oxygen saturation during the endurance shuttle walk test. | SpO2 measured by continuous transcutaneous recordung via Sentec-Digital Monitor® (Sentec, Therwil, Switzerland). | Day 1 and Day 2 | 
| Time to desaturation (SpO2 <=90%) and to severe desaturation (SpO2 <=85%) | SpO2 measured by continuous transcutaneous recordung via Sentec-Digital Monitor® (Sentec, Therwil, Switzerland) and FreeO2 Device. | Day 1 and Day 2 | 
| Change of capillary partial pressure of CO2 (pCO2) during endurance shuttle walk test | pCO2 measured by capillary blood gases taken before and after the ESWT. | Day 1 and Day 2 | 
| Change of capillary partial pressure of O2 (pO2) during endurance shuttle walk test | pO2 measured by capillary blood gases taken before and after the ESWT. | Day 1 and Day 2 | 
| Change of partial pressure of CO2 (pCO2) during endurance shuttle walk test | pCO2 measured by continuous transcutaneous recording via Sentec-Digital Monitor® (Sentec, Therwil, Switzerland) | Day 1 and Day 2 | 
| Change of heart rate during endurance shuttle walk test | Heart rate measured by continuous transcutaneous recordung via Sentec-Digital Monitor® (Sentec, Therwil, Switzerland). | Day 1 and Day 2 | 
| Change of breathing frequency during endurance shuttle walk test | Breathing frequency during the ESWT measured by ApneaLink Air™ (ResMed, ...) | Day 1 and Day 2 | 
| Patients Preference due to oxygen delivery system | Patients will be asked to rate their experienced comfort after each ESWT | Day 1 and Day 2 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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hypoxemia, exercise, oxygen, automatic oxygen-titration