Blood
About 98.5% of the oxygen in a sample of arterial blood in a healthy human breathing air at sea-level pressure is chemically combined with the hemoglobin. About 1.5% is physically dissolved in the other blood liquids and not connected to hemoglobin. The hemoglobin molecule is the primary transporter of oxygen in mammals and many other species (for exceptions, see below). Hemoglobin has an oxygen binding capacity between 1.36 and 1.40 ml O per gram hemoglobin, which increases the total blood oxygen capacity seventyfold, compared to if oxygen solely were carried by its solubility of 0.03 ml O per liter blood per mm Hg partial pressure of oxygen (about 100 mm Hg in arteries).
Biopure
In Hemopure, the average oxygen content is maximized due to the reduced size of the stabilized HBOC molecules in comparison to red blood cells (RBCs). Oxyglobin primarily differs from Hemopure in molecule size of the stabilized HBOC. Oxyglobin is approved for oxygen fluid therapy and an alternative to RBC transfusion in dogs, and is administered intravenously as well. The stabilized HBOC then flows through the blood plasma in the body, where oxygen transport takes place. Due to the reduced size of the HBOC in Hemopure, oxygen can be transported to restricted areas where normal RBCs fail to reach. Another advantage of this patented oxygen technology is the increased shelf life of 36 months through storage conditions at room temperature, while RBCs must be refrigerated and discarded if not used after six weeks. However, these products are only indicated for temporary oxygen replenishment through the oxygen bridge, with an average half-life of 19 hours (specifically Hemopure), therefore long term oxygen support requires RBC blood transfusion.