WHAT IS BLOOD TRANSFUSION

DEFINITION

Blood transfusion is the process of transferring blood or blood products from one person into the circulatory system of another.

USES

•   Blood transfusions can be life saving in some situations such as massive blood loss due to trauma.

•  Blood can be used to replace blood lost during surgery.

•    Blood can be used to treat severe anaemia (low HB or thrombocytopenia or low platelet count) caused by a blood disease.

•    Patients with Haemophilia or sickle-cell disease require life long suport with frequent blood transfusions.

TYPES OF BLOOD TRANSFUSION

Blood transfusions can be grouped into two main types depending on source:

(A)  ALLOGENEIC (HOMOLOGOUS)

Transfusions using the stored blood of other persons- THE BLOOD DONOR.

(B)  AUTOLOGOUS

Transfusions using the patient’s own stored blood.

PROCEDURES/PROCESSES

STORAGE

Donated blood must be kept refrigerated at specified temperatures to prevent bacterial growth and to slow cellular metabolism hence extending its shelf life.

Transfusion must begin within 30 minutes after blood being taken out of controlled storage.

BLOOD DONATION

Blood is commonly donated as whole blood by inserting a needle into a vein and collecting it in a plastic bag mixed with anticoagulant. A unit of blood is up to 500mls including the preservative. Red cells, Plasma and Platelets can also be donated individually via a more complex process called Apheresis. This allows for higher product yields and allows doctor to reduce multiple donor antigen exposure of the patient hence improving treatment outcomes and less chances of treatment failure.

BLOOD AND BLOOD PRODUCTS

Collected blood is separated into components to make best use it. Blood components and Blood products include:

(a)   COMPONENTS

(i)                 Red blood cells

(ii)               Plasma

(iii)             Platelets

(b)   BLOOD PRODUCTS

(i)                 Albumin

(ii)               Clotting factor concentrates

(iii)             Cryoprecipitate

(iv)             Fibrinogen concentrate

(v)               Immunoglobulins (antibodies)

ADMINISTRATION

§  Blood can only be administered intravenously, requires that an intravenous canula of suitable size is inserted into a vein.

§  A unit (450mls) is typically administered over 4 hours.

§  In patients at risk of heart failure doctors may administer a diuretic to prevent fluid overload.

§  Antihistamines maybe administered prior to transfusion to prevent allergic transfusion reactions which are common but usually not fatal.

§  Positive patient identification is critical to patient safety. The personal details of the patient are matched with the blood to be transfused to minimise risk of transfusion reactions.

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

By Dr. Gabriel Muyinda

Executive Director - Zambia National Blood Transfusion Service.