Effect of Oxygen Therapy for Patients With Precapillary Pulmonary Hypertension Who Experience an Altitude Related Adverse Health Effect (ARAHE) During 30h Exposure to 2500m

Proportion of patients with precapillary pulmonary hypertension experiencing an ARAHE at 2500 m of high altitude and receiving oxygen therapy titrated to achieve SpO2 ≥ 90% who recover from ARAHE, have improved symptoms and achieve constant work-rate exercise time within a minimal important difference as defined for patients with respiratory disease within 1.75 min of baseline value at 490 m; time frame within 6 h after initiation of oxygen therapy.

Difference with oxygen therapy at high altitude vs. low altitude in constant work-rate exercise time cycle exercise test at 75% Wmax at low altitude

Difference with oxygen therapy at high altitude vs. low altitude in maximal exercise capacity during a incremental ramp cycle exercise test

Difference with oxygen therapy at high altitude vs. low altitude in hemodynamics assessed by echocardiography at rest including pulmonary artery pressure, cardiac output, pulmonary vascular resistance and right heart function assessed as tricuspid plane systolic excursion and fractional area change.

Difference with oxygen therapy at high altitude vs. low altitude baseline in post-exercise Borg dyspnoea scale going from 1-10 scores with higher values meaning worse dyspnea

Difference with oxygen therapy at high altitude vs. low altitude baseline in symptoms assessed by the Visual Analogue Scale for dyspnoea, a 10cm line from left to right where patients have to add a cross-line with higher values meaning better feeling.

Difference with oxygen therapy at high altitude vs. low altitude baseline in cognitive function tests

Difference with oxygen therapy at high altitude vs. low altitude baseline in sit-to-stand test

Difference with oxygen therapy at high altitude vs. low altitude in sleep disordered breathing

Difference with oxygen therapy at high altitude vs. low altitude in 6 minute walk test

Difference with oxygen therapy at high altitude vs. low altitude baseline in symptoms assessed by the Lake Louise acute mountain sickness score going from 0-12 points with mild AMS as 3-5 points, moderate AMS as 6-9 points, and severe AMS as 10-12 points.