Clinical trial NCT03592927: Acute Exposure to Simulated Hypoxia on Exercise Capacity
Official title: Acute Exposure to Hypoxia in Precapillary Pulmonary Hypertension: Physiological and Clinical Effects at Rest and During Exercise
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Pulmonary Hypertension
Keywords: exercise capacity
simulated altitude
Lead sponsor: University of Zurich
Sponsor class: OTHER
First posted: 2018-07-19
Enrollment: 28
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Including a baseline assessment and assessments under simulated altitude and normoxia.
Primary purpose: PREVENTION

Brief summary: 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.

Detailed 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.

Eligibility criteria: 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

Primary outcomes:
measure: Endurance time under hypoxia (FiO2: 15.1%)
timeFrame: Towards the end of a one hour exposure
Secondary outcomes:
Other outcomes:
Locations:
city: Zurich
country: Switzerland
facility: Respiratory Clinic, University Hospital of Zurich
Study officials:
affiliation: University of Zurich
name: Silvia Ulrich, Prof.
role: PRINCIPAL_INVESTIGATOR
References:
citation: Schneider SR, Lichtblau M, Furian M, Mayer LC, Berlier C, Muller J, Saxer S, Schwarz EI, Bloch KE, Ulrich S. Cardiorespiratory Adaptation to Short-Term Exposure to Altitude vs. Normobaric Hypoxia in Patients with Pulmonary Hypertension. J Clin Med. 2022 May 14;11(10):2769. doi: 10.3390/jcm11102769.
citation: Schneider SR, Mayer LC, Lichtblau M, Berlier C, Schwarz EI, Saxer S, Furian M, Bloch KE, Ulrich S. Effect of Normobaric Hypoxia on Exercise Performance in Pulmonary Hypertension: Randomized Trial. Chest. 2021 Feb;159(2):757-771. doi: 10.1016/j.chest.2020.09.004. Epub 2020 Sep 9.