Blood transfusion

Blood transfusion is the process of transferring bloodor blood-based products from one person into the circulatory systemof another. It can be considered a form of organ transplant^{[citation needed]}. Blood transfusions may treat medical conditions, such as massive blood loss due to trauma, surgery, shockand where the red cell producing mechanism (or some other normal and essential component) fails (see blood diseases).

History

Roman Catholicauthors take pains to discredit the contemporary chronicler Stefano Infessura's story of Innocent VIII's deathbed. In 1492, as the Popesank into a coma, the harrowing story was told that, at the suggestion of a physician, the blood of three boys was infused into the dying pontiff's veins. They were ten years old, and had been promised a ducateach. All three died. Historians of medicine note this event as the first reported historical attempt at a blood transfusion.

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With Harvey's discovery of the circulation of the blood, more sophisticated research into blood transfusion began in the 17th century, with successful experiments of transfusions between animals. However, successive attempts on humans continued to bring death.

The first fully-documented human blood transfusion was administered by Dr. Jean-Baptiste Denyson June 15, 1667. He transfused the blood of a sheepto a 15-year old boy (the boy later died, and Denys was accused of murder).

Only in the first decade of the 19th centurywas the reason for such death found in the existence of blood types, and the practice of mixing some blood from the donor and the receiver before the transfusion allowed a greater number of successes.

In 1818 Dr.James Blundell, a British obstetrician, performed the first successful transfusion of human blood to a patient for the treatment of postpartum hemorrhage. He used the patient's husband as a donor, and extracted four ounces of blood from his arm to transfuse into his wife. During the years 1825 and 1830, he performed 10 transfusions, five of which were beneficial and published his results. He also invented many instruments for the transfusion of blood. He made a substantial amount of money from this endeavour, roughly $50 million in real dollars.

In 1840, at St. George's School in London, Samuel Armstrong Lane, aided by Dr. Blundell, performed the first successful whole blood transfusion to treat hemophilia.

While the first transfusions had to be made directly from donor to receiver before coagulation, in the 1910sit was discovered that by adding anticoagulantsand refrigeratingthe blood it was possible to store it for some days, thus opening the way for blood banks. The first non-direct transfusion was performed on March 27, 1914by the Belgiandoctor Albert Hustin, who used sodium citrateas an anticoagulant. The first blood transfusion using blood that had been stored and cooled was performed on January 1,1916. It was performed by the Royal Army Medical Corps(RAMC), and the procedure was very successful.

The first blood transfusion institute was set up by Alexander Bogdanov(who would sacrifice his own life in one of the experiments) in Moscowin 1925.

There is an urban legendconcerning one of the pioneers of blood transfusion research, Dr. Charles Drew. Drew's research led to the discovery that blood could be separated into blood plasmaand red blood cells, and that the components could be frozen separately. Blood stored in this way lasted longer and was less likely to become contaminated. His untimely deathafter an automobileaccident is commonly believed to have resulted partly from delayed access to emergency blood transfusion treatment because of his race. The popular televisionseries M*A*S*Honce aired an episode(see Season 2, Episode 9 - "Dear Dad ... Three") propagating this legend. Contemporary eye-witness accounts however, contradict that version.

Precautions

Great care is taken to ensure that the recipient's immune systemwill not attack the donor blood, and also to avoid transfusing white blood cellsthat could initiate an immune attack on the host (graft versus host disease). Nevertheless, blood transfusion does suppress the immune system, increasing the risk of complications after surgery.

In addition to the familiar human blood type(A, B, AB and O) and Rhesus(positive or negative) classifications, other red cell antigensare known to determine compatibility, to one degree or other. These other type become increasingly important in people who receive many blood transfusions as their bodies develop increasing resistance to blood from other people.

There is increased awareness that a number of diseases (such as AIDS, syphilis, hepatitis Band hepatitis Cand others) can be passed from the donor to recipient. This has led to strict human blood transfusion standards in developed countries, such as HIV blood screening. Standards include screening for potential risk factors and health problems including determining donor hemoglobinlevel, and answering a set of standard oral and written questions, as well as testing donated units for these infections. The lack of such standards in places like rural China, where desperate villagers donated plasma for money and had others' red blood cells reinjected, has produced entire villages infected with AIDS.

When a person's need for a transfusion can be anticipated, as in the case of scheduled surgery, autologousdonation can be used to protect against disease transmission and eliminate the problem of blood type compatibility.

Procedure

Blood can only be administered intravenously. It therefore requires the insertion of a cannulaof suitable caliber. Before the blood is administered, the personal details of the patient are matched with the blood to be transfused, to minimize risk of transfusion reactions.

A unit (up to 500 ml) of blood is typically administered over 4 hours. In patients at risk of congestive heart failure, many doctors administer furosemideto prevent fluid overload.

Contraindications

The contraindications to a blood donor include:

• previous malaria or hepatitis.
• history of drug abuse
• donors who have received human pituitary hormone.
• donors with high risk sexual behaviour
• donors who have previously been transfused (12-month min. deferral)

Sometimes only parts of the blood are taken as a donation. Blood is made up mostly of plasma, red blood cells, white blood cellsand platelets. Plasma and platelets can be donated separately in a process called ~apherisis. Blood is usually separated into components after being donated to make the most use of it. Donation of whole blood is generally reserved for treating young children and remote areas where the hospital summons donors when it needs them. Resulting blood component products also include albuminproteinused to treat burns, clotting factor concentrates used to treat hemophilia, cryoprecipitate, fibrinogen concentrate, and immunoglobulinantibodiesfor immunological disorders.

Donation of whole blood eliminates transfusion-related risk of illness for the blood donor, aside from the minuscule chance of infection or perhaps of localized injury to the donor site. While there is a theoretical risk to the donor when they donate plasma and have red cells reinfused, this risk is eliminated by proper sterilization procedures. However, this caused public health disasters in China where this practice was often unregulated. Modern, well-run blood plasmacollection centers are completely safe. In some developed countries including the United States, they are maintained by pharmaceutical companies, using paid donors up to twice weekly; in others they rely on unpaid donors and are operated by non-profit organisations such as the Australian Red Cross.

Donations are usually anonymous to the recipient, but products in a blood bankare always individually traceable through the whole cycle of donation, testing, separation into components, storage, administration to the recipient. This enables management and investigation of any suspected transfusion related disease transmission.

Complications

Possible complications in the recipient include:

• Febrile reactions
• Haemolytic reactions
• Allergic reactions
• Infection
• Fluid overload
• Acute respiratory distress syndromespecifically transfusion-related acute lung injury(TRALI)
• Transfusion-associated graft versus host disease(TA-GVHD)

Animal blood transfusion

Veterinariansalso administer transfusions to animals. Various speciesrequire different levels of testing to ensure a compatible match. Catshave 3 blood types, cattlehave 11, dogshave a dozen, pigs16 and horseshave 34.

The rare and experimental practice of inter-species blood transfusions is a form of xenograft.

Blood transfusion substitutes

There are currently no clinically acceptable oxygen-carrying blood substitutesfor humans, however, there are widely available non-blood volume expanders and other blood saving techniques. These are helping doctors and surgeons avoid the risks of disease transmission and immune suppression, address the chronic blood donor shortage and address the religious objections of Jehovah's Witnesses.

A number of blood substitutes are currently in the clinical evaluation stage. Most attempts to find a suitable alternative to blood have so far concentrated on cell-free hemoglobin solutions. Blood substitutescould make transfusions more readily available in emergency medicineand in pre-hospital EMScare. If successful such a blood substitute could save many lives, particularly in traumas where massive blood loss results.

See also

• Blood donation
• Coombs test
• Phlebotomist
• Intravenous therapy
• Blood substitutes
• Luis Agote
• Norman Bethune

References

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This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Blood+transfusion Wikipedia article Blood transfusion.