Blood plasma
Blood plasma is the straw-colored/pale-yellow liquid component of blood that normally holds the blood cells in whole blood in suspension. It makes up about 55% of total blood volume. It is the intravascular fluid part of extracellular fluid (all body fluid outside of cells). It is mostly water (93% by volume) and contains dissolved proteins, glucose, clotting factors, mineral ions, hormones and carbon dioxide (plasma being the main medium for excretory product transportation). Plasma also serves as the protein reserve of the human body. It plays a vital role in intravascular osmotic effect that keeps electrolyte in balance form and protects the body from infection and other blood disorders.[1]
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.[2] Blood plasma has a density of approximately 1025 kg/m3, or 1.025 kg/l.[3]
Blood serum is blood plasma without fibrinogen or the other clotting factors (i.e., whole blood minus both the cells and the clotting factors).[2] Plasmapheresis is a medical therapy that involves blood plasma extraction, treatment, and reintegration.
Composition
| Ion | Normal concentration range (mmol.l−1) |
|---|---|
| Sodium | 135-145 |
| Potassium | 3.7-5.1 |
| Chloride | 95-105 |
| Calcium | 2.1-3.7 |
 |
 |
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 interstitium, causing "third spacing."
If one stands still for a prolonged period, this causes an increase in transcapillary hydrostatic pressure. As a result, approximately 12% of blood plasma volume crosses into the extravascular compartment. This causes an increase in hematocrit, serum total protein, blood viscosity and, as a result of increased concentration of coagulation factors, it causes orthostatic hypercoagulability.[4]
Medical history
"Dried plasmas" were developed and first used in World War II. 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 began in August 1940 to collect blood in New York City hospitals for the export of plasma to Britain. 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 into the first successful mass production techniques.
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.[5] The resulting dried plasma package came in two tin cans containing 400 cc bottles. One bottle contained enough distilled water to 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.[6]
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 policy would lead to needless deaths as soldiers and sailors were required to wait for "same race" blood.[7]
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 the Korean War.[8]
Plasma donation
Plasma is used in blood transfusions, typically as fresh frozen plasma (FFP) or Plasma Frozen Within 24 Hours After Phlebotomy (PF24). When donating whole blood or packed red blood cell (PRBC) transfusions, ABO blood type O- is the most desirable and is considered a "universal donor," since it has neither A nor B antigens and can be safely transfused to most recipients. Type AB+ is the "universal recipient" type for whole blood or PRBC donations. However, for plasma the situation is somewhat reversed. Blood donation centers will sometimes collect only plasma from AB donors through apheresis, as their plasma does not contain the antibodies that may cross react with recipient antigens. As such, AB is often considered the "universal donor" for plasma. Special programs exist just to cater to the male AB plasma donor, because of concerns about transfusion related acute lung injury (TRALI) and female donors who may have higher leukocyte antibodies.[9] However, some studies do not show an increased risk of TRALI despite increased leukocyte antibodies in women who have been pregnant.[10]
Safety and compensation to donors
In contrast to whole blood donation, plasma donation may be done much more often (2 times per week in some jurisdictions, compared to once per 8 weeks for whole blood donation), because the whole blood cells are returned to the body during the donation process, and most plasma is naturally replaced by the body within 48 hours. Also in contrast to whole blood donation, plasma donors are often compensated financially ($10-$100 per week for 5 +/- 2 hours of time, normally). It is usually a compensation for time and trouble, not a "purchase" or "sale" of a body part, for various legal, ethical, and cultural reasons. Professional donation centers use sterile and safe practices. They process the plasma and sell it as a highly quality controlled medical product, selling the product for as high as $1200/week/donor. They set their donor compensation not as a percentage of the expected income, but rather according to how many donors they need, based upon demand for the product and supply of donations.
See also
References
- ^ "Ways to Keep Your Blood Plasma Healthy". Retrieved November 10, 2011.
- ^ a b Maton, Anthea (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1.
{{cite book}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ The Physics Factbook - Density of Blood
- ^ Masoud M, Sarig G, Brenner B, Jacob G (2008). "Orthostatic hypercoagulability: a novel physiological mechanism to activate the coagulation system". Hypertension. 51 (6): 1545–51. doi:10.1161/HYPERTENSIONAHA.108.112003. PMID 18413485.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Transfusion before World War I
- ^ Plasma Equipment and Packaging, and Transfusion Equipment
- ^ Hirsch, Eric (1991). What Your 1st Grader Needs to Know: Fundamentals of a Good First-Grade Education. pp 232-233. New York: Doubleday.
- ^ The Plasma Program
- ^ "AB Plasma Donor Program". NIH Clinical Center. March 20, 2008. Retrieved 2011-03-18.
- ^ "Female Plasma May Not Increase Risk for Transfusion-Related Acute Lung Injury". Medscape. October 23, 2007. Retrieved 2011-07-02.