Blood Transfusions

Posted on March 15, 2008
Filed Under Blood Transfusion |

What is a transfusion?
Transfusion therapy is a procedure involving the intravenous injection to a person of a considerable amount of blood from a donor. For this to take place with due efficiency and safety is very important to observe a series of laboratory and clinical procedures, from the time the blood is obtained from the donor until it is injected to the receiver, ensuring the maximum therapeutic benefit and minimum risk possible.

Donation
The gesture of solidarity that involves donating a small part of our blood (which is no more than 10% of the total blood of our organization) to benefit those who need it is still necessary today as it is not possible to replace this precious tissue in the body.

When a person chooses to donate their blood should go to a bank of blood from a hospital or a mobile sensor unit of donations on the street. There shall be informed of the basic profile that must have a suitable donor will be diagnosed and you are asked about whether it meets some basic conditions, or if it is a trait that has made the donation inadvisable. You will be asked to fill out this form which sets out the conditions and requirements. This first phase is necessary to exclude those who might have reasonable doubts about their suitability as donors.

Optimum conditions of the donor are regulated by law in all countries. In Spain you can summarize the basic criteria underlying the rules according to the following sections:
* With over 18 years and under 65, who came by choice and not have donated blood in the last 2 months.
* With good general health and normal (weight, blood pressure and heart rate normal, no fever, no cause of unexplained illnesses, they have operated recently without being bound by medication side effects, patents, etc.). .
* Available from any disease or at risk of having acquired in the last year (together with infectious patients, having received transfusions in the past year by unsafe sex, coming from countries or areas with endemic or epidemic diseases, etc. .).
* Available also in certain non-communicable diseases (heart disease, hyperthyroidism, insulin-dependent diabetes, cancer, anemia, blood coagulation diseases, epilepsy, gastroduodenal ulcer, severe asthma, allergy medications, etc.)…
* Available in the risk of being under the influence of toxic substances (drug addicts, people treated with certain drugs, etc.)…
Complying with the right conditions, the donation does not involve any special risk to anyone. The donation process usually lasts no more than ten or fifteen minutes and the amount drawn must be that a full bag of 450 cc. If you can not get this amount, the gift is usually discarded.

After obtaining a blood analysis is done to it to verify that the donor is healthy and free from diseases. This is determined, usually by serological tests to detect the presence of antibodies to certain viruses, bacteria and parasites. These antibodies usually appear within days or weeks in people who get an infection.

When it comes to the conclusion that safe blood is not receiving any possible risks, it is split into different useful components for transfusion concentrate red blood cells (the cells that transport oxygen), platelet concentrate (the cells that repair damage to blood vessels) and plasma (blood fluid containing the remaining seroproteínas) mainly.

The splitting of blood is possible because this is their best use and a safer job. The fractional blood is also used to obtain concentrates of clotting factors (proteins that are essential to stop bleeding) and other derivatives (albumin, immunoglobulins, white blood cells, etc.).

What types of transfusions are there?
Transfusions may take various forms depending on the need to provide the receiver under the condition that suffers. The donation is the most common red blood cell concentrates (red blood cells). The diseases that can make vital transfusion of concentrated red blood cells are numerous (severe bleeding, acute leukemia, anemia after chemotherapy and radiotherapy treatments for cancer, bone marrow aplasia, major surgery, myelodysplastic syndrome, hemolytic anemia, etc..), But all common key is the existence of a severe anemia that can not be corrected by other means and seriously jeopardizing the cardio circulatory function of blood and oxygen to the body.

Anemia is the situation where there is a shortage of hemoglobin, the oxygen carrier protein, present in red blood cells. If anemia is always occurs because there is no blood in a sufficient amount of hemoglobin, which generally corresponds to an unrealistically low number of red blood cells, but not always. Therefore, the key figure of the blood of a person who requires a transfusion is the hemoglobin level, which indicates the total oxygen from your blood. When this figure is less than 9 g / dL is usually required transfusions of concentrated red cells, but if the doctor is convinced that hemoglobin may be increased in patients with a good predictable evolution of the disease or other therapy, can decide not. The key to the final decision lies above all in the general state of the patient and the reversibility of anemia or other means.

The number of pockets of concentrated red blood cells required varies according to each case, but one must decide the size just to ensure total recovery of an appropriate minimum level of hemoglobin to overcome their bad situation, no more any less.

Platelet transfusion is another type of blood needed for some patients. A platelet concentrate is obtained by combining the appropriate fractions from several whole blood donations, so the platelets are derived from the blood more precious still.

Obtaining platelet concentrates not only done by the sum of the number of platelets extractions. It is also possible to obtain concentrates of platelets by apheresis procedures quote. This technique yields a concentrate of platelets from a donor and is selectively removing a small percentage of such cells in their blood. This is achieved by passing blood from one arm of the donor to a machine that is only removed from the platelets. Then, the machine returns the remaining blood to the donor injected into a vein in the arm opposite. The process usually lasts no more than 2 hours and involves risks not worth mentioning in the vast majority of donors.

Diseases that require the donation of platelets are those that produce a severe deficit of these cells in the blood and an increased risk of bleeding for this cause (acute leukemia, hemorrhagic worsening picture, liver transplant surgery, bone marrow aplasia syndrome myelodysplastic, politransfusión of red cells, etc.) platelet transfusion is usually indicated when the amount in the blood drops to less than 50,000 plaquetas/mm3 and there is clear risk of bleeding. When the level drops to less than 10,000 plaquetas/mm3 the risk of bleeding is such that transfusion is usually indicated if ever there are no other therapeutic alternative that can raise that figure immediately.

Other possible transfusions are fresh frozen plasma or factor concentrates, which are often required in cases where there is partial or total deficit of certain blood proteins, especially clotting factors. Transfusion of white blood cells is also possible for severely immunocompromised patients, but currently is not usually used on a regular basis.

Today it is very unusual to indicate that blood transfusion is rare that a patient requires more than a derivative transfusion and because it is not medically acceptable risk and the added advantage that can lead to improper input from other blood components not required.

What risks involving transfusions?
Transfusion today is an extremely safe procedure. This is due to meet strict security measures that ensure careful selection of appropriate healthy donors, a careful fractionation, processing and storage of blood bags and an allocation of safe transfusion to the recipient in terms of compatibility. To perform this last phase of the process is essential to concentrate transfusions are of the same blood type as the receiver. There are many known blood groups, but the most important of all the systems belonging to the ABO and Rh antigen, but there are other systems that must be taken into account in the allocation of blood in transfusions.

To do so, before transfusion is always done in the lab tests what is called cross. They are facing a small sample of blood from the receiver with different blood samples of the concentrated pockets of same blood group ABO and Rh of the same, and choosing only those where there is no rejection of the mixture. In this way only those products that are transfused not react with the blood of the recipient, thus ensuring a safe transfusion therapy and proper performance.

All these safety measures to reduce the possibility for extremely low rates of side effects associated with transfusion therapy. However, it is not yet possible to eliminate such hazards so absolute. Therefore the general approach is to prescribe a transfusion only when strictly necessary.

Some of the risks, often rare, are the transmission of infectious diseases, for various reasons, including: poor maintenance of products, transmission of a donor who is not clinically manifested infection (and neither has been detected with previous study undertaken recently for their illness); group incompatibility reactions, allergic reactions, fever Post (for the transmission of pyrogens, are substances that promote the onset of fever, or cells that produce these substances); complex effects type immune, or effects of politransfusión.

Why is still required transfusion therapy?
For some diseases there are now alternative treatments for transfusion. In many patients, for a few years ago there was no other option; it is now possible to treat with erythropoietin, a hormone produced continuously by the kidney, and whose principal effect is to stimulate production of red blood cells. Over the last few years has been to synthesize this material and now many patients with anemia benefit from therapeutic use of this hormone. Unfortunately, there is still the possibility of pharmacological use of a hormone similar to production of platelets, called trombopoyetina but expected this to be a reality in the not too distant future.

The technology that permits the manufacture of synthetic preparations of blood or fluids capable of linking similar oxygen remains investigational and should take several years to come.

Until then, it remains imperative to maintain and stimulate solidarity which is the act of donating our blood, but on a regular basis, not to mention that throughout the year in our hospitals is an ongoing need for blood.

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