الفهرس 
Physiology of BloodOnly 14 pages are availabe for public view
 |  | from | 119 |  |  |
| | | from | 119 | | |
Abstract
The need for human blood for blood transfusion is steadily increasing due to an increase in ageing population, and decreased allogenic donations. However, donated human blood has many problems. The maintenance of intravascular volume is essential and resuscitation with isotonic crystalloid or volume expanders such as gelofusin or penta-starch is fundamental in the management of shock, with the addition of packed red cells when available, to restore oxygen carrying capacity and oxygen delivery to reinstate tissue perfusion.
There are two main indications for the transfusion of red cells: [1] Severe hemorrhage, & [2] chronic symptomatic anemia for which no specific therapy exist. Although of its great benefits, donated blood may exert an immunosuppressive effect on the recipient, making them more susceptible to infections, and may lead to various metabolic conditions, such as Hyperkalaemia, Hypocalcaemia and Alkalosis.
The development of artificial oxygen carriers include:
1. Perfluorocarbons: they are synthetic oxygen carriers composed of eight to ten hydrocarbon molecules where the hydrogen atom has been replaced by fluorine; they are biologically and chemically inert. They possess high gas dissolving properties. They are not miscible with water and therefore have to be brought into an emulsion prior to use. Perfluorocarbons have short intravascular half-life of 12-18 hours, but are only cleared from the
body weeks later, preventing multiple doses in a short time span.
2. Hemoglobin-based solution: they would seem to be a natural substitute for red cells that need some chemical modification to form a stable, functional tetramer of hemoglobin which would not dissociate into dimers upon infusion. They are derived from three principal sources: human, bovine and genetically engineered hemoglobin.