Efficacy of Positive Expiratory Pressure on Acute Mountain Sickness

Efficacy of Positive Expiratory Pressure on Acute Mountain Sickness, a Pilot Crossover Trial at 6000 Meters

This pilot study aims to evaluate the efficacy of positive expiratory pressure (PEP) therapy at 10 cmH₂O in improving peripheral oxygen saturation (SpO₂) and mitigating symptoms of acute mountain sickness (AMS) in healthy individuals exposed to extreme altitude conditions.

Three male participants will be monitored during an ascent of Mount Aconcagua, Argentina, at elevations of 4,300 m, 5,560 m, and 6,000 m above sea level. The study involves three sequential phases of 10 minutes each: baseline breathing without PEP, breathing with PEP applied via a mechanical face mask, and post-PEP breathing.

Primary outcomes include changes in SpO₂ and Lake Louise Score (LLS) to assess AMS severity. Findings will provide preliminary data on the potential role of PEP as a non-pharmacological intervention in high-altitude medicine.

Inclusion Criteria:

• Healthy volunteers without ongoing medical conditions
• Over 18 years of age
• Volunteers with the physical and technical skills necessary to undertake a mountaineering expedition on Mount Aconcagua, Argentina, and with previous experience at extreme altitudes

Exclusion Criteria:

• Subjects with any ongoing medical conditions
• Under 18 years of age
• Subjects without previous mountaineering experience at extreme altitudes and without adequate physical and technical preparation necessary to undertake a mountaineering expedition on Mount Aconcagua, Argentina