Autologous Blood Donation Health Article

Definition

Autologous blood donation is the process of donating one's own blood prior to an elective surgical or medical procedure to avoid or reduce the need for an allogeneic blood transfusion (from a volunteer blood donor).

Purpose

Blood transfusions are given to restore lost blood, to improve clotting time, and to improve the ability of the blood to deliver oxygen to the body's tissues. There are some disadvantages to traditional allogeneic blood transfusions. Although strict regulations are in place to ensure correct matching by blood type, errors in this process can lead to the transfusion of mismatched blood, which can cause a serious and sometimes fatal adverse reaction called transfusion reaction. In addition, while donated blood is rigorously tested for infectious agents such as human immunodeficiency virus (HIV) and hepatitis, there is always a chance that an infectious disease may be transmitted via allogeneic transfusion.

The donation and transfusion of autologous blood has arisen as an alternative to allogeneic blood transfusion. Autologous donation is indicated for an elective surgical or medical procedure in which the likelihood of a blood transfusion is high. Such procedures include surgery on the heart, blood vessels, bones, and chest.

Some of the advantages of autologous blood donation include:

• The patient is assured that the blood is an exact match to his or her blood type, thereby avoiding transfusion reaction.
• There is no risk of inadvertently transmitting infectious agents.
• Autologous blood donations supplement the community blood supply.
• The process of donating blood promotes blood cell production by bone marrow.
• The patient is often reassured by the knowledge that his or her own blood will be used if a blood transfusion becomes necessary.

Some disadvantages to autologous blood donation do exist, which include:

• Contamination of autologous blood with infectious agents is possible during the donation process.
• There is a possibility that a patient's blood will be mislabeled or that allogeneic blood will be inadvertently transfused.
• Autologous blood donation costs more to process and store.
• Blood may be transfused unnecessarily because an autologous blood supply exists.
• Unused units of autologous blood are usually disposed of; approximately 44% of autologous donations remain unused after surgery.

Demographics

Autologous blood donations account for approximately 5% of all blood donated in the United States each year.

Description

The most common form of autologous donation is called preoperative autologous blood donation (PABD). PABD is generally indicated when there is a reasonable chance that a blood transfusion will become necessary, when the patient is in adequate health to donate blood, and when there is sufficient preoperative time for the patient to donate. As the shelf life of liquid blood is approximately 42 days, the patient may begin donating up to six weeks before the scheduled procedure. It is generally recommended that a patient donate no more than once or twice a week, and no later than 72 hours before surgery.

The PABD process is similar to the process of donating allogeneic blood. A tourniquet is placed on the upper arm to increase the pressure in the arm veins and make them swell and become more accessible. Once a suitable vein is identified, the area where the needle will be inserted is sterilized by washing with soap solution or an iodine-containing antiseptic. The donor lies on a bed or cot during the procedure, which takes about 10 minutes. Blood is collected in sterile plastic bags that hold one pint (450 ml). The bags contain an anticoagulant to prevent clotting and preservatives to keep the blood cells alive.

The collected blood may then be transfused during and/or after surgery in a similar manner to allogeneic blood. If the amount transfused is less than anticipated or if no blood was necessary, then the autologous blood is generally disposed of (since the restrictions placed on volunteer donors are stricter than those on autologous donors). If the patient's surgery is postponed, the donated blood may be frozen and stored until the procedure is rescheduled.

Acute normo-volemic hemodilution (ANH) is a variant of autologous donation in which a volume of the patient's blood is removed directly before surgery and replaced with fluids so that any blood lost during surgery has a lower red blood cell count (i.e., the red blood cells have been diluted). The removed blood is then reinfused after surgery. Advantages to ANH are that no processing and storage costs are necessary and the risk of contamination during processing is reduced.

Blood may also be collected during surgery (intraoperative blood salvage, or IBS) or after surgery (postoperative blood salvage, PBS). IBS is commonly used during cardiac, bone, transplant, and trauma surgery and involves the use of specialized equipment to collect and process the blood before reinfusion. PBS involves the collection of blood from drainage tubes, although generally this volume is small.