Time course of asymptomatic interstitial pulmonary oedema at high altitude

► Interstitial pulmonary oedema was assessed at 4350 m by ultrasonography. ► Interstitial pulmonary oedema was clearly observed the first 2 days at altitude. ► Transient interstitial pulmonary oedema is part of acclimatization to high altitude. ► It does not relate to changes in left ventricle function or pulmonary hypertension.