AUTHOR=Lichtblau Mona , Saxer Stéphanie , Latshang Tsogyal D. , Aeschbacher Sayaka S. , Huber Fabienne , Scheiwiller Philipp M. , Herzig Joël J. , Schneider Simon R. , Hasler Elisabeth D. , Furian Michael , Bloch Konrad E. , Ulrich Silvia 

TITLE=Altitude Travel in Patients With Pulmonary Hypertension: Randomized Pilot-Trial Evaluating Nocturnal Oxygen Therapy

JOURNAL=Frontiers in Medicine

VOLUME=Volume 7 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2020.00502

DOI=10.3389/fmed.2020.00502

ISSN=2296-858X

ABSTRACT=Introduction
Stable patients with pulmonary arterial or chronic thromboembolic pulmonary hypertension (PH) wish to undergo altitude sojourns or air travel but fear disease worsening. This pilot-study investigates health effects of altitude sojourns and potential benefits of nocturnal oxygen therapy (NOT) in PH-patients.
Methods
Nine stable PH-patients, age 65 (47;71), 5 women, in NYHA class II, on optimized medication, were investigated at 490m and during two sojourns of two days/nights at 2048m, once using NOT, once placebo (ambient air), 3L/min per nasal cannula, according to a randomized cross-over design with 2 weeks washout at <800m. Assessments included safety, nocturnal pulse oximetry (SpO2), 6-minute walk distance (6MWD) and echocardiography.
Results
At 2048m, 2 of 9 patients required medical intervention, one for exercise-induced syncope, one for excessive nocturnal hypoxemia (SpO2<75% for >30min). Both recovered immediately with oxygen therapy. 2 patients suffered from acute mountain sickness. In 6 patients with complete data, nocturnal mean SpO2 and cyclic SpO2 dips reflecting sleep apnea significantly differed from 490m to 2048m with placebo, and 2048m with NOT (medians, quartiles): SpO2 93(91;95)%, 89(85;90)%, 97(95;97)%; SpO2 dips 10.4/h(3.1;26.9), 34.0/h(5.3;81.3), 0.3/h(0.1;2.3). 6MWD at 490m, 2048m without and with NOT was: 620m (563;720), 583m(467;696) and 561m(501;688). Echocardiographic indices of heart function and PH were unchanged at 2048m with/without NOT vs. 490m.
Conclusions
7/9 PH patients stayed safely at 2048m but revealed hypoxemia, sleep apnea and reduced 6MWD. Hemodynamic changes were trivial. NOT improved oxygenation and sleep apnea. The current pilot-trial is import for designing further studies on altitude tolerance of PH-patients.