Artificial Blood

Better known as blood surrogates/substitutes, artificial blood serves two main purposes like filling the fluid volume and carry oxygen and other gases in blood through the entire cardiovascular system. It should be noted that nothing could replace the human blood since it performs innumerable other functions apart from these. So the accurate term for the product performing first function could be volume expanders and the gas carriers could be named Oxygen therapeutics.

In simple words, Volume expanders are certain passive materials which raise the blood quantity. They are of two types, mainly colloid based like Voluven, Haemaccel, gelofusin etc. and crystalloid based where Ringer's lactate, normal saline are examples. The case of Oxygen Therapeutics, they function as a substitute for the oxygen carrying ability of the body fluid. Common examples are Hemopure, Oxygent, PolyHeme and Perftoran. Depending on the mode of the transport mechanism, Oxygen therapeutics fall into two main streams called per fluorocarbon based and hemoglobin based.

Volume expanders are common and easily obtained in markets and they are mainly used for first aid and in case of trauma. Consider the case of trauma and when there is a loss of blood, there arises a necessity to prevent blood loss. Another requirement is the substitution of lost amount of body fluid. And the remaining RBC's can provide oxygen for the tissues.

Oxygen Therapeutics is employed to imitate the oxygen carrying ability of normal blood. But the modern science find it difficult to develop a completely efficient therapeutic and hence two fundamental approaches has been installed to assemble an oxygen therapeutic. Now, per fluorocarbons (PFCs) a chemical compound that transports and gives out oxygen is made use of. The frequently used PFC is per fluorodecalin. Their main property is that it will not get assorted with blood and hence there arises a need to produce emulsions that are made by dispersing minute droplets of PFC in water. This emulsion is then mixed with antibiotics, vitamins, nutrients and also salts, thus making an emulsion that consists of some 80 different types of constituents and that will perform a lot of the important purposes of body fluid. They are just 1/40 the size of the diameter of the Red Blood Cells and this minute structure will help them to seep into the very minute and dead capillaries where normal blood flow is almost absent. The per fluorocarbon solutions can transport oxygen; hence the mammals and human beings could survive by just breathing the liquid per fluorocarbon solution, termed the liquid breathing.

It is to be noted that 33% of the entire Red blood cell mass is consisted by the Hemoglobin. The Hemoglobin-associated materials are termed HBOCs (Hemoglobin Based Oxygen Carriers). As red blood cell contains certain other substances other than the hemoglobin it is quite difficult to extract hemoglobin alone from blood. If used, it will end up in a condition called renal toxicity which could be considered fatal. By making use of the following processes like self linking, polymerization and encapsulation hemoglobin could be extracted and could be used in a safer way too. Fluosol-DA-20, the only approved HBOC by Food and drug Administration, is now banned with its least success and the increase in the number of side effects.

The artificial blood seems advantageous in different walks of life. As discussed earlier, the small size of oxygen therapeutics will seem superior to normal body fluid and hence it could lessen the number of transfusions which is being increasing day by day.

If such a system is employed nobody needs to become much fearful about the hazards during a blood transfusion like the spreading of AIDS and anthrax viruses.

In case of trauma or in certain battlefields the blood surrogates or the blood substitutes find wide varieties of applications. In future, let's hope that no patient dies due to unavailability of blood.

The main advantage of blood substitutes is that it could be stored for much longer time as compared to the transfused blood. It is capable of using at anytime with a tension free mind.

The major merit of artificial blood is that it supports instantaneous full capability for the transport of oxygen, a contradiction to blood which is transfused that need some 24 hours to arrive at complete oxygen transport ability because of the depletion of 2,3-diphosphoglycerate.