النقل والتبرع بالدم

Transfusion

Most hospital blood banks also perform testing to determine the
blood type of patients and to identify compatible
blood products for blood transfusions, along
with a battery of tests (e.g. disease) and treatments (e.g. leukocyte
filtration) to ensure and enhance quality. Some such procedures can be done
"upstream" by the collecting agency, or a contracted laboratory. The
increasingly-recognized problem of inadequate efficacy of transfusion and
post-transfusion complications[1] raises the importance of
quality testing and screening; in fact, U.S. hospitals spend more on dealing
with the consequences of transfusion-related complications donors are sometimes
paid. In the U.S. and Europe, most blood for transfusion is collected from
volunteers while plasma (specifically plasma) for manufacturing is from paid
donors.
In the US, certain standards are set for the collection and
processing of each blood product. "Whole blood" (WB) is the proper name for one
defined product, specifically unseparated venous blood with an approved
preservative added. Most blood for transfusion is collected as whole blood. Autologous donations are sometimes transfused
without further modification, however whole blood is typically separated (via
centrifugation) into its components, with Red Blood Cells (RBC) in solution
being a commonly used product. Units of WB and RBC are both kept refrigerated at
1-6 C, with maximum permitted storage periods (****f lives) of 35 and 42 days
respectively.
Red Blood Cell units can also be frozen when buffered with
glycerol, but this is an expensive and time consuming process, and is rarely
done. Frozen red cells are given an expiration date of 3 years and are stored at
-65C.
The less-dense blood plasma is made into a
variety of frozen components, and is labeled differently based on when it was
frozen and what the intended use of the product is. If the plasma is frozen
promptly and is intended for transfusion, it is typically labeled as fresh frozen plasma. If it is intended to be made
into other products, it is typically labeled as recovered plasma or plasma for
fractionation. Cryoprecipitate can be made from other plasma
components. These components must be stored at -18C or colder, but are typically
stored at -30C.
The layer between the red cells and the plasma is referred to
as the buffy coat and is sometimes removed to make platelets for transfusion. Platelets are typically
pooled before transfusion and have a ****f life of five days, or three days once
the transfusion centre that collected them has completed their tests. Platelets
are stored at room temperature (20-24C) and must be agitated. Since they are
stored at room temperature in nutritive solutions, they are at high risk for
growing bacteria.
Some blood banks also collect products
by apheresis. The most common component collected is
plasma via plasmapheresis, but red
blood cells and platelet can be collected by similar methods. These products
have the same ****f life and storage conditions as their manually-produced
counterparts. An ongoing study allows platelets collected by apheresis to be
kept for seven days, but only with specific microbiological testing. The lack of
a preservative solution makes a longer ****f life of little
use.
Short-term Storage

Routine blood storage is limited to several weeks (5 for WB, 6
for RBC), and involves refrigeration but usually not freezing. There has been
increasing controversy about whether the age of blood is a factor in transfusion
efficacy, specifically on whether older blood directly or indirectly increases
risks. complications.[2]
Long-term
Storage

Cryopreservation of red
blood cells is done to store rare units, usually for up to 3 years. Very rare
units may be kept even longer [3]. The cells are incubated
in a glycerol solution which acts as a cryoprotectant ("antifreeze") within the cells. The
units are then placed in special sterile containers in a freezer at very cold
temperatures. The exact temperature depends on the glycerol
concentration.
History

An early development leading to the establishment of blood banks
occurred in 1915, when Richard Lewison of Mount Sinai Hospital in New York City initiated the use of sodium citrate as an anticoagulant. This discovery transformed the blood
transfusion procedure from direct (vein-to-vein) to indirect. In the same year,
Richard Weil demonstrated
the feasibility of refrigerated storage of anticoagulated blood. The
introduction of a citrate-glucose solution by
Francis Peyton Rous and JR Turner two years later
permitted storage of blood in containers for several days, thus opening the way
for the first "blood depot" established in Britain during World War I. Charles R. Drew researched in the field of blood
transfusions, developing improved techniques for blood storage, and applied his
expert knowledge in developing large-scale blood banks early in World War II. Oswald Hope Robertson, a medical researcher and U.S. Army officer who established the depots, is
now recognized as the creator of the first blood bank. The University of Louisville is
also credited for the Blood Bank.


[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة]




Blood donation at the Royal Melbourne Hospital
during the 1940s.


By the mid-1930s, the Soviet Union had set up a system of at least sixty
large blood centers and more than 500 subsidiary ones, all storing "canned"
blood and shipping it to all corners of the country. News of the Soviet
experience traveled to America, where in 1937 Bernard Fantus, director of therapeutics at the
Cook County Hospital in Chicago, established the
first hospital blood bank in the United States.[4] In creating a hospital
laboratory that preserved and stored donor blood, Fantus originated the term
"blood bank." Within a few years, hospital and community blood banks were
established across the United States. Willem Johan Kolff organised the first blood
bank in Europe (in 1940).
An important breakthrough came in 1939-40 when
Karl Landsteiner, Alex Wiener, Philip Levine, and
R.E. Stetson discovered the Rh blood group system, which was found to be the
cause of the majority of transfusion reactions up to that time. Three years
later, the introduction by J.F. Loutit and Patrick L. Mollison of acid-citrate-dextrose (ACD) solution, which reduces
the volume of anticoagulant, permitted transfusions of greater volumes of blood
and allowed longer term storage.
Carl Walter and W.P. Murphy, Jr., introduced
the plastic bag for blood collection in 1950. Replacing breakable glass bottles
with durable plastic bags allowed for the evolution of a collection system
capable of safe and easy preparation of multiple blood components from a single
unit of Whole Blood.
An anticoagulant preservative, CPDA-1 was introduced in
1979. It decreased wastage from expiration and facilitated resource sharing
among blood banks. Newer solutions contain adenine.