Hypobaric hypoxia does not affect lung fluid or protein exchange in awake adult sheep at rest

We measured pulmonary artery (Ppa) and left atrial (Pla) pressures, lung lymph flow, and lymph/plasma protein concentrations in four adult sheep at a barometric pressure of 380 Torr (1 Torr = 133.322 Pa) for 22 h. Hypobaric hypoxia caused an immediate increase in Ppa from 20 to 39 Torr. There was no significant change in Pla, lymph flow, or lymph protein concentrations. We conclude that hypobaric hypoxia does not affect lung fluid or protein exchange in awake adult sheep at rest.