BLOOD-GAS TRANSPORT AT HIGH-ALTITUDE

As a model of human hypoxia, exposure to high altitude causes a number of ventilatory, circulatory and hemopoietic adaptations. A review of the literature on blood gas transport responses to hypoxia indicates t hat they are influenced not only by altitude, but also by factors rela ted to acclimatization. In addition, it appears that the need to oxyge nate tissues conflicts with the need to maintain Hf homeostasis. Thus, the final situation represents a compromise between the respiratory a djustment aimed at increasing blood alkalosis in order to optimize the oxygen transport system, and the metabolic readjustment aimed at rees tablishing normal blood pH. There are factors like red cell 2,3-diphos phoglycerate, a compound that decreases the hemoglobin affinity for ox ygen, that can influence that balance by affecting arterial oxygen sat uration through mechanisms independent of respiration.