EFFECTS OF OXYGEN ON BLOOD FORMATION AND DESTRUCTION

Publisher Summary This chapter describes the effects of oxygen on blood formation and destruction. Blood is normally exposed to a P O2 of 100 mmHg at the alveolar capillary level, resulting in O 2 saturation of approximately 98% of the available hemoglobin. As hemoglobin is essentially saturated at normal ambient P 02 , increasing the O 2 tension can only augment the blood's oxygen-carrying capacity by increasing the amount of O2 that is physically dissolved. Under hyperoxic conditions, the only O 2 increase to which the formed elements of the blood are exposed is the O 2 physically dissolved in the water of blood plasma and cells. The chapter presents a series of blood studies including measurements of RBC mass. Crew members and test subjects in the several projects were exposed to very different breathing atmospheres, ranging from pure O 2 in the space flights to mixtures of O 2 with He or N 2 in the diving situations.