Acute Exposure of Simulated Hypoxia on Heart Rate and Ventilation During Exercise

Study Overview
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Brief Summary
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Randomized crossover trial in patients with Pulmonary Hypertension (PAH, CTEPH) to assess the acute response to simulated altitude (FIO2: 15.1% = equivalent to 2500m above sea level) on heart rate and Ventilation changes under exercise.

Detailed Description
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Low altitude baseline measurements will be performed in Zurich (469m asl) including Echocardiography, right heart catheterization, six-minute walk test (6MWT), pulmonary function test, clinical assessment and blood gas analysis at rest and under exercise. Randomly assigned to the order of testing, the participants will be tested under simulated altitude (FiO2: 15.1% with the AMC Altitrainer) and shamed altitude with the same device. During the exposure to simulated altitude (FiO2: 15.1%) and shamed altitude of 1 hour each, the participants' heart rate and Ventilation will be compared under exercise.

Official Title
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Acute Exposure to Hypoxia in Precapillary Pulmonary Hypertension: Physiological and Clinical Effects at Rest and During Exercise

Conditions
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Pulmonary Hypertension

Intervention / Treatment
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* Device: Simulated Altitude: (FiO2: 15.1)
* Device: Shamed Hypoxia (FiO2: 20.9)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Informed consent PH diagnosed according to internation Guidelines: mean pulmonary artery pressure (mPAP) ≥ 25 mmHg along with a pulmonary artery wedge pressure (PAWP) ≤15 mmHg during right heart catheterization at the time of Initial diagnosis PH class 1 (PAH) or 4 (CTEPH) Stable condition, on the same medication for > 4 weeks Patient live permanently at an altitude < 1000m asl. Exclusion Criteria: Resting partial oxygen pressure (PaO2) ≤7.3 kilopascal (kPA) corresponding to the requirement of long-term oxygen therapy > 16hour daily (nocturnal oxygen therapy alone is allowed) Severe daytime hypercapnia (pCO2 > 6.5 kPa) Susceptibility to high altitude related diseases (AMS, high-altitude pulmonary edema (HAPE), etc.) based on previous experienced discomfort at altitudes. Exposure to an altitude >1500m for ≥3 nights during the last 4 weeks before the study participation Residence > 1000m above sea level Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, neurological or orthopedic problems with Walking disability Women who are pregnant or breast feeding

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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Including a baseline assessment and assessments under simulated altitude and normoxia
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Order A<br>The participants will be consecutively exposed to shamed hypoxia (FiO2: 20.9%) equivalent to sea level and to simulated altitude (FiO2: 15.1%) equivalent to 2500m above sea level administered by an altitude simulator (Altitrainer, SMTEC) with a facemask. | Device: Simulated Altitude: (FiO2: 15.1)<br>* Inhalation of deoxygenated air through an altitude simulator (Altitrainer) for approximately 1 hour given by a facemask.<br>Device: Shamed Hypoxia (FiO2: 20.9)<br>* Inhalation of unmodified air through an altitude simulator (Altitrainer) for approximately 1 hour given by a facemask.<br>|
| Experimental: Order B<br>The participants will be consecutively exposed to hypoxia (FiO2: 15,1%) equivalent to 2500m above sea level and to shamed hypoxia (FiO2: 20.9%) equivalent to sea level administered by an altitude simulated (Altitrainer, SMTEC) with a facemask. | Device: Simulated Altitude: (FiO2: 15.1)<br>* Inhalation of deoxygenated air through an altitude simulator (Altitrainer) for approximately 1 hour given by a facemask.<br>Device: Shamed Hypoxia (FiO2: 20.9)<br>* Inhalation of unmodified air through an altitude simulator (Altitrainer) for approximately 1 hour given by a facemask.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| heart rate under exercise | Change in heart rate under exercise during the exposure to simulated altitude (FiO2: 15,1%) and normoxia. | 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ventilation under exercise | Change in Ventilation under exercise during the exposure to simulated altitude | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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heart rate, Simulated altitude, exercise, ventilation