Acute Exposure to Simulated Hypoxia on Exercise Capacity

University of Zurich28 enrolled

Overview

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.

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Enrollment

Conditions

Pulmonary Hypertension

Interventions

Simulated Altitude (FiO2: 15.1%)DEVICE

Inhalation of deoxygenated air through a altitude simulator ("Altitrainer"), for approx. 1 hour. given by a facemask.

Shamed Hypoxia (FiO2: 20.9)DEVICE

Inhalation of unmodified air through an altitude Simulator ("Altitrainer") for approximately 1 hour given by a facemask

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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

Locations (1)

Respiratory Clinic, University Hospital of Zurich

Zurich, Switzerland

Outcomes

Primary Outcomes

Endurance time under hypoxia (FiO2: 15.1%)

Constant loaded exercise test

Time frame: Towards the end of a one hour exposure

Data from ClinicalTrials.gov

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