AUTOLOGOUS BLOOD AS AN ALTERNATIVE
TO ALLOGENEIC BLOOD TRANSFUSION

“Autologous” transfusions refer to those transfusions in which the blood donor and transfusion recipient are the same. “Allogeneic” transfusions refer to blood transfused to someone other than the donor.

Preoperative Donation

The most common autologous donation is the preoperative donation of blood for possible transfusion back to the donor during elective surgery. For example, a person might give one unit of blood each week for up to six weeks before surgery, because blood can be stored in its liquid form for up to 42 days. Preoperative autologous donation is not allowed within 72 hours of surgery due to the time needed for recovery from donation. Approximately 10 percent of body iron stores are removed with each autologous donation. When appropriate, iron supplements are prescribed for patients making autologous donations to help increase red blood cell count.

Autologous donation is most often employed in surgery on bones, blood vessels, the urinary tract and the heart, when the likelihood of transfusion is high. Potential autologous blood donors are medically stable patients who are free of infection. There is no age limitation for autologous donation. Many children and elderly patients have successfully completed autologous donations; however, some patients may not be good candidates. The decision regarding autologous donation and transfusion should be made jointly by the physician and the patient.

The process of donating autologous blood stimulates the bone marrow to produce new blood cells. Given adequate time for recovery, the collected cells may be replaced prior to surgery. If blood loss is less than anticipated, transfusion of autologous blood may not be medically necessary. Although the risk of a complication from autologous blood is low, some residual risk persists making automatic transfusion of autologous units unwise. Almost one-half of autologous donations are unused. These units are discarded since current standards do not allow transfusion of these units to another patient for safety reasons. Due to the special handling and separate storage requirements, autologous donations cost more to process.

Blood Dilution (Hemodilution)

Blood dilution, or hemodilution, is the removal of one or more units of blood at the beginning of surgery for transfusion to the patient during or at the end of the operation. Hemodilution is used

to decrease the loss of red blood cells during surgery. In this procedure, blood is drawn from a patient before surgery, and the patient is immediately given intravenous fluids to compensate for the amount of blood removed. Since the number of red blood cells in the person's circulatory system has been diluted, fewer red blood cells will be lost from bleeding during the operation. After surgery, the patient’s own blood is reinfused.

Intraoperative Blood Collection

In intraoperative blood collection, blood lost by the patient during surgery is recovered and recycled throughout the surgery. Most intraoperative blood collection programs use machines in which shed blood is collected and the red blood cells are concentrated and washed prior to transfusion. This procedure is widely used for surgical procedures, such as cardiac, vascular, orthopedic, urologic, trauma, gynecologic and transplant surgery, in which the anticipated blood loss is 20 percent or more of the patient's estimated blood volume.

Postoperative Blood Collection

In postoperative blood collection, blood that is lost in the early postoperative period is collected from a drainage tube at the surgical site and transfused to the patient, either washed or unwashed. Postoperative collection is used primarily in cardiac surgery.