Acute Exposure to Simulated Hypoxia on Exercise Capacity

University of Zurich (UZH)

Status: Completed

Conditions: Pulmonary Hypertension

Treatments: Device: Shamed Hypoxia (FiO2: 20.9); Device: Simulated Altitude (FiO2: 15.1%)

Study type: Interventional

Funder types: Other

Identifiers

NCT03592927

2018-00455_A1

Details and patient eligibility

About

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) in constant loaded exercise capacity.

Full description

Low altitude baseline measurements will be performed in Zurich (460m asl) including Echocardiography, Right heart catheterization, six-minute walk test (6MWT), pulmonary function test, clinical assessment and blood gas Analysis.

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.

Towards the end of the exposure after approximately 1h, the participants will perform a constant loaded exercise test on an Ergometer with a calculated resistance of their 60% max. workload.

The patients will be encouraged to perform this test up to their physical exhaustion.

Enrollment: 28 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Informed consent
• PH diagnosed according to internation Guidelines: mean pulmonary artery presssure (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

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Single Blind

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28 participants in 2 patient groups

Order A

Experimental group

Description:

The participants will be exposed to shamed hypoxia (FiO2: 20.9% equivalent to sea level and consecutively to simulated altitude (FiO2: 15.1% equivalent to 2500m above sea level) administered by an altitude Simulator ("Altitrainer", SMTEC), simulated altitude (FiO2: 15.1%), with a facemask.

Treatment:

Device: Simulated Altitude (FiO2: 15.1%)

Device: Shamed Hypoxia (FiO2: 20.9)

Order B

Experimental group

Description:

The participant will be exposed to hypoxia (FiO2, 15.1% equivalent to 2500m above sea level), simulated altitude (FiO2: 15.1%), and consecutively to shamed hypoxia (FiO2, 20.9%) administered by an altitude simulator ("Altitrainer", SMTEC) with a facemask.

Treatment:

Device: Simulated Altitude (FiO2: 15.1%)

Device: Shamed Hypoxia (FiO2: 20.9)