Acute Exposure of Simulated Hypoxia on Cardiac Output

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 non-invasive cardiac output assessments by Finapres® NOVA Technology at rest and under exercise.

Detailed Description
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Low altitude baseline measurements will be performed in Zurich (470m 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 cardiac output non-invasively assessed will be measured throughout the whole intervention.

Official Title
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Acute Exposure of Simulated Hypoxia on Non-invasive Cardiac Output Assessments 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: Prevention
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 Sham/Hypoxia<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 Hypoxia/Sham<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 |
| --- | --- | --- |
| Cardiac Output measured non-invasively | Change in non-invasive assessed cardiac output measured with a finger cuff (Finapres) during the exposure to simulated altitude (FiO2: 15.1%) compared to normoxia | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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simulated altitude, exercise, non-invasive cardiac output