High altitude pulmonary edema is a life-threatening condition that remains a concern for climbers and clinicians alike. It is defined as a non-cardiac pulmonary edema occurring at altitudes exceeding 3000m in non-acclimatised individuals. Recently, studies conducted in remote areas have demonstrated that ultrasound lung comets (B lines) can be used as a measure of sub-acute pulmonary edema and high altitude pulmonary edema in climbers ascending to altitude. the investigators want to assess the occurrence of of comet tails (B lines) as a measure of pulmonary edema among patients after lung transplantation and healthy individuals during an expedition to Mount Kilimanjaro.