BLOOD PLASMA

Blood plasma is the yellow liquid component of blood, in which the blood cells in whole blood would normally be suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid. It is mostly water (90% by volume) and contains dissolved proteins, glucose, clotting factors, mineral ions, hormones and carbon dioxide (plasma being the main medium for excretory product transportation). Blood plasma is prepared by spinning a tube of fresh blood containing an anti-coagulant in a centrifuge until the blood cells fall to the bottom of the tube. The blood plasma is then poured or drawn off. Blood plasma has a density of approximately 1025 kg/m3, or 1.025 kg/l. 

Blood serum is blood plasma without fibrinogen or the other clotting factors (i.e., whole blood minus both the cells and the clotting factors). 

Plasmapheresis is a medical therapy that involves blood plasma extraction, treatment, and reintegration.

FRESH FROZEN PLASMA AND OTHER TRANSFUSED PLASMAS

"Fresh frozen plasma" (FFP) is prepared from a single unit of blood or by apheresis, drawn from a single person. It is frozen to −40 °C (−40.0 °F) after collection and can be stored for ten years from date of collection. The term "FFP" is sometimes used informally to mean any frozen transfusable plasma product, including products which do not meet the standards for FFP. FFP contains all of the coagulation factors and proteins present in the original unit of blood. It is used to treat coagulopathies from warfarin overdose, liver disease, or dilutional coagulopathy. Other transfusable plasma is identical except that the coagulation factors are no longer considered completely viable. This is particularly important for Factor VIII and hemophilia, but these have been mostly replaced by more specific Factor VIII concentrates in the developed world and true FFP is rarely used for that indication.

Plasma used as a source of Cryoprecipitate (Plasma, Cryoprecipitate Reduced) cannot be used for treatment of some coagulation problems but is still acceptable for many uses.

DRIED PLASMA

"Dried plasma" was developed and first used in WWII. Prior to the United States' involvement in the war, liquid plasma and whole blood were used. The "Blood for Britain" program during the early 1940s was quite successful (and popular in the United States) based on Dr. Charles Drew's contribution. A large project was begun in August of the year 1940 to collect blood in New York City hospitals for the export of plasma toBritain. Dr. Drew was appointed medical supervisor of the "Plasma for Britain" project. His notable contribution at this time was to transform the test tube methods of many blood researchers, including himself, into the first successful mass productiontechniques.

Nonetheless, the decision was made to develop a dried plasma package for the armed forces as it would reduce breakage and make the transportation, packaging, and storage much simpler. 

The resulting Army-Navy dried plasma package came in two tin cans containing 400 ccbottles. One bottle contained enough distilled water to completely reconstitute the dried plasma contained within the other bottle. In about three minutes, the plasma would be ready to use and could stay fresh for around four hours. 

Following the "Plasma for Britain" invention, Dr. Drew was named director of the Red Cross blood bank and assistant director of the National Research Council, in charge of blood collection for the United States Army and Navy. Dr. Drew argued against the armed forces directive that blood/plasma was to be separated by the race of the donor. Dr. Drew argued that there was no racial difference in human blood and that the policywould lead to needless deaths as soldiers and sailors were required to wait for "same race" blood. 

By the end of the war the American Red Cross had provided enough blood for over six million plasma packages. Most of the surplus plasma was returned to the United States for civilian use. Serum albumin replaced dried plasma for combat use during theKorean War.

PLASMA SHIFT

Blood plasma volume may be expanded by or drained to extravascular fluid when there are changes in Starling forces across capillary walls. For example, when blood pressure drops in circulatory shock, Starling forces drive fluid into the blood vessels, causing autotransfusion.

Also prolonged still standing causes an increase in transcapillary hydrostatic pressure. As a result, approximately 12% of blood plasma volume crosses into the extravascular compartment. This causes and increase in hematocrit, serum total protein, blood viscosity and, as a result of increased concentration of coagulation factors, it causes orthostatic hypercoagulability.