Introduction:

A recent National Heart, Lung, and Blood Institute expert panel concluded that despite significant reduction in the risk of transfusion transmitted viruses, the transfusion of autologous blood remains safer than that of allogeneic blood and is appropriate for properly selected patients. Exclusive or supplemental use of autologous blood can prevent adverse effects of transfusion, including bloodborne viral transmission, immunologic transfusion reactions, and sensitization. On the other hand, collection of autologous blood in patients with a low probability of transfusion (hence, a high discard rate of donated units) is the major factor reducing its cost-effectiveness.

The rationale for directed donor transfusions stems largely from the perception among the public that blood obtained from persons they know may be safer than that from the regular volunteer donor population. Based on prevalence studies of viral markers, however, physicians should be aware of the lack of objective evidence to support this belief when considering transfusion options with their patients. It should also be recognized that directed donations are not as safe as the patient’s own blood and should not be considered equivalent to autologous blood donations.

Patient Selection For Autologous Donations:

Candidates for autologous donation are patients undergoing elective surgery that is likely to require transfusion. Examples include patients who are undergoing total hip replacement, spine surgery with instrumentation, and individuals undergoing coronary artery bypass surgery in whom the time required to collect autologous units will not compromise patient safety or outcome. A useful guide for estimation of the number of units required is the hospital’s maximum surgical blood order schedule (MSBOS).

Autologous donation can be utilized in children weighing at least 65 pounds and is generally a safe procedure, even for elderly patients. However, vasovagal reactions, which occur in 1-4% of all blood donations, may carry the risk of greater morbidity for some patients with unstable cardiac or cerebral vascular disease. A recently reported survey found that 1 in 16,000 autologous donors had a reaction severe enough to warrant hospitalization. The Institute’s medical staff are available to assist with questions regarding donor suitability and the need for special monitoring. Additional factors which determine eligibility include the absence of infection (in order to exclude possible bacteremia and proliferation in the stored blood component) and the presence of adequate red cell mass (hemoglobin and hematocrit 11gm/33%).

Autologous Donation Technique: Autologous units may be stored and used as whole blood, but are usually processed into packed red blood cells; fresh frozen plasma may also be prepared from the latter. Liquid-stored red blood cells have a shelf-life of 35-42 days depending upon the anticoagulant. Once a surgery date is confirmed and the physician prescribes the amount of units needed, patients may be scheduled at one of Central Blood Bank’s (CBB) 20 community donor centers throughout the area. In general, donations begin 3-4 weeks before surgery; the individual may donate every 3 to 7 days until the requested number of units have been drawn. The last donation should ideally be at least one week before surgery, but no less than 72 hours prior to surgery to allow sufficient time to regenerate the patient/donor’s red cell mass and blood volume. A single unit donation a few days before surgery will not be beneficial because minimal red blood cell regeneration will occur.

Iron therapy (e.g., FeSO₄ 325 mg p.o. t.i.d.) is necessary since inadequate iron reserves is the major limitation to completing the donation schedule. This is particularly true in female donors. Should surgery be postponed, the hospital blood bank and CBB should be contacted so that the red cells may be frozen, if necessary. Freezing the collected units is also an option if an insufficient number of red cell units is collected due to hematocrit deferral (less than 33%) and the patient’s physician decides to reschedule surgery. This would permit additional time to collect the prescribed amount in order to maximize availability of autologous blood and minimize allogeneic donor exposures.

While recombinant erythropoietin therapy has also been proposed to maximize availability of autologous blood, it is not Food & Drug Administration (FDA)- approved for this indication. However, this strategy might permit the patient who is already anemic to build up sufficient red blood cell mass in order to allow self-donation.

Directed Donation Procedure:

Since there is no established medical advantage in using directed donors, the same rigorous screening criteria used to safeguard both the health of the donor and the transfusion recipient are followed as for regular volunteer blood donors. Directed donation requests require advanced planning to allow time for scheduling of donors, blood collection, processing (including testing), and shipping, as well as cross-matching at the hospital. CBB’s Special Donations Department generally requests that extra donors be recruited in order to insure that a sufficient number of compatible units are available. It is recommended that females of child-bearing age not receive directed donations from husbands/or sexual partners because of the risk of sensitization to minor blood group antigens, which may cause hemolytic disease of the newborn.

Policies:

Directed donations between blood relatives are gamma-irradiated using 2500 cGy in order to prevent transfusion-induced graft-vs-host disease. Since directed donors must meet all regular blood donor criteria, unused units may be "crossed-over" for general use unless notified otherwise by the patient’s physician.

Unused autologous blood is stored for the patient’s peri-operative needs until the unit outdates or until the patient is discharged (according to specific hospital policy); it is then discarded. All CBB autologous units are labeled "For Autologous Use Only", because many of these units do not meet the stricter standards established for allogeneic blood. In accordance with FDA requirements, CBB performs all regular donor testing on autologous donations. Because of the potential biohazard, units reactive for anti-HIV 1/2, and Hepatitis B surface antigen are discarded. In instances where markers other than these (anti-HCV, HBcAb etc.) are reactive, the patient’s physician is notified and determines whether to continue the donation schedule and the appropriateness for transfusion.

Hospital policies differ regarding comparative indications for transfusion of autologous or allogeneic blood. Since precise indications for a blood transfusion are often difficult to define, the lower risk for autologous blood supports a more liberal transfusion threshold. On the other hand, because some risk of unrecognized bacterial contamination remains, the transfusion of autologous red blood cells to the mildly anemic or non-anemic patient who would derive no benefit is inappropriate.

Questions:

Contact CBB’s Donor Resources Office (412 209-7063) or Dr. Joseph E. Kiss (412 209-7326) for further information on these important community programs.