No evidence for interstitial lung oedema by extensive pulmonary function testing at 4,559 m

Area of Science:

• Physiology
• Altitude Medicine
• Pulmonary Function

Background:

• Understanding lung function changes at high altitude is crucial for mountaineers and researchers.
• Previous studies suggested alterations in pulmonary mechanics with ascent to high elevations.

Purpose of the Study:

• To investigate comprehensive pulmonary function changes in mountaineers at high altitude.
• To assess the impact of high altitude on lung volumes, capacities, and gas exchange.

Main Methods:

• Pulmonary function testing using body plethysmography and closing volume assessment.
• Measurements were taken at sea level and repeatedly over 2 days at 4,559 m in 34 mountaineers.
• Evaluated parameters included total lung capacity, forced vital capacity, lung compliance, airway resistance, and diffusing capacity for carbon monoxide.

Main Results:

• No significant differences in total lung capacity, forced vital capacity, closing volume, or lung compliance were observed at high altitude compared to sea level in subjects without high-altitude pulmonary oedema (HAPE).
• Lung diffusing capacity for carbon monoxide significantly increased at high altitude.
• Airway resistance and bronchodilator responsiveness remained unchanged, excluding bronchoconstriction as a cause for altered closing volumes.
• Mild alveolar edema in HAPE cases was associated with minor decreases in forced vital capacity, diffusing capacity, and lung compliance, and slight increases in closing volume.

Conclusions:

• Comprehensive lung function testing showed no evidence of interstitial pulmonary edema in mountaineers without HAPE during the initial 2 days at 4,559 m.
• Existing pulmonary function tests may not be sensitive enough to detect early, mild interstitial fluid accumulation in high-altitude pulmonary edema.