A Medical Technologist at a level I trauma center in the midwest asks about trauma patients with multiple antibodies: "At what point should antigen typing of the red blood cells be omitted to speed delivery of blood products? Should particular antigen typings occur while others ignored until the demand for red blood cells decreases?"

The following comments have been received.

ADDENDA May 15, 2007

1. Dr. Tim Goodnough, Medical Director of the Stanford transfusion service (attribution used with permission) reports that his institution has a "non-standard" policy for massive transfusion situations such as trauma, liver transplantation, complex cardiac surgeries, etc. which allows medical exceptions for special need indications, such as leukoreduced, irradiated, CMV negative, etc products. For other special needs such as Rh specificity and phenotype-negative units, they try to provide these for the initial 10 units transfused, and the last 10 units transfused. Close communication with the clinical services at each of these two time points is critical in assessing the need for addition units at the first instance, and establishing control of the hemorrhaging patient in the second instance. If time permits, they can continue to phenotype selectively for such antibodies known to fix complement such as the Kidd antibodies, for example.

ADDENDA May 22, 2007

2. A Transfusion Service Medical Director in the New England Region shares the following opinion:

• Obtain verbal agreement from OR about the need to ignore some antibodies, and assure their understanding of the relative difficulty to obtain fully compatible blood and that this constitutes an emergency release
• Request use of one cell saver and possibly two cell savers to salvage blood lost into the surgical field if possible (bowel cases is a contraindication usually)
• Insist on coagulation testing (INR, platelet count, fibrinogen) every 1/2 hour or 1/2 blood volume loss (Request that they get additional OR staff help if necessary to assist with this).
• Ignore clinically insignificant antibodies (P1, Lewis, M)- or antibodies usually clinically insignificant

Then start with the following:

• Ignore undetectable antibodies (historical antibodies)
• Ignore antibodies NOT associated with acute hemolytic reactions, (even if they are likely to lead to a delayed hemolytic reaction postop) if bleeding and blood loss is tremendous (OR orders for blood to stay 4 or 8 ahead)
• Do not ignore detectable antibodies that are highly likely to be associated with overt hemolytic reactions such as anti-K, anti-Jk(a), and anti-D.

After 10 units of RBCs are transfused (1 whole blood volume is lost) switch to partially matched or no matching whatsoever, other than ABO and possibly Rh.

When bleeding or blood use slows down, switch back to partial and if possible fully compatible units.

Most importantly, start assemblying and setting aside (do not use immediately) enough fully compatible, antigen negative RBCs (call the regional and national blood centers if need be) to equal one blood volume (8 to 10 units). If possible, start giving these once majority of bleeding is controlled (requires communication with OR/Anesthesia). Aim to have this many by 12-24 hours postop if delivery by out of region is required. If out of region blood is required, OR must be notified of this, and use of rFVIIa is considered. Alternatively, recommended staged surgery (i.e. stabilization with packing, followed with more surgery later on to get enough units of RBCs).

Obviously if the bleeding is tremendous and antigen typing cannot be done due to inadequate time, then it becomes a non-issue if imminent exsanguination exceeds the risk of incompatibilility outside of ABO, but even then, once things calmed down, he would try to implement some of the above.

While the above is generally agreed upon by him and his supervisory and senior technologists, he admits that it is not a written policy, and is now considering writing one based on this recent discussion.

3. Dr. Holli M. Mason, Director of Transfusion Medicine and Serology at Harbor/UCLA Medical Center in Torrance, California (attribution used with permission) reports that constant communication between the Emergency Department and the blood bank is key. When exsanguination is imminent, taking the time to do antigen typing will result in delays that could cause the patient to die or suffer from the effects of extreme anemia (cardiac ischemia, etc). As the urgency of the situation decreases it is a good idea to do what one can as far as antigen typing given the time constraints at any given time during the situation. She would prioritize antigen typing to those most likely to be associated with severe reactions and/or the frequency in the population. She does not recall who said it, but she is familiar with a famous quote in the blood bank world "we can support incompatible transfusions [not referring to ABO mismatch, but to minor antigen incompatibility], but we can't support the dead."

ADDENDA May 25, 2007

4. A transfusion medicine physician in San Antonio, Texas reports that their approach to the massively bleeding patient who has alloantibodies is individualized to each situation. However it follows two general principles:
• Avoid a potential acute intravascular hemolytic reaction
• Issue RBC units as fast as they are needed.

After a patient has received the equivalent of one blood volume (8-10 units of RBC), a new specimen is requested so that it can be determined whether any antibody has been diluted enough to become undetectable. If so, they would ignore this antibody, since it would not be expected to cause an acute hemolytic reaction. They would follow up later, after the patient has stabilized, for a possible delayed hemolytic process.

They would rank the antibodies according to each one's acute hemolytic potential. They would also consider the availability of RBC units lacking the corresponding antigen. For example, if one of the antibodies is anti-K, 90% of donor RBC units are K negative; it would not significantly increase the availability of blood to ignore anti-K. In general they ignore Rhesus antibodies as these antibodies do not fix complement. They try to respect Duffy antibodies, if at all possible. She comments that they have great respect for Kidd antibodies' ability to fix complement and cause intravascular hemolysis, so they always try, if possible, to respect Kidd antibodies. And, of course, they don't pay attention to anti-Lewis, anti-M and anti-P1 antibodies in these dire situations. They place anti-S and anti-s at about the same level as Duffy antibodies but would more readily ignore anti-s, as this antibody, if respected, would cause a severe decrease in blood availability.

In screening units they would start with finding Kidd antigen phenotyped units (if the patient has a Kidd antibody), as these antibodies are very significant and if present would take 75% of the units out. The remaining 25% of the units would be screened for K (if applicable).

The AABB published a small booklet "Guidelines for massive transfusion" in 2005. On page 14, it specifically states that after 8-10 units RBC have been transfused "it is acceptable to issue antigen-negative RBCs without performing a major crossmatch" and "if the supply of antigen-negative RBCs is exhausted, incompatible units can be issued with approval of the physician covering the transfusion service". It then describes a strategy of preserving 8-10 antigen-negative units for use when the patient's condition is stabilized. While this is good strategy, it does take some very close communication between the transfusion service physician and the clinical team to be effectively accomplished.

ADDENDA May 30, 2007

5. Dr. Glenn Ramsey, Director of Transfusion Services at Northwestern University in Chicago (attribution used with permission) reports that most of his hospital's experience has been with liver transplant patients for which there is usually on a few hours lead time. For a massively bleeding patient with red cell antibodies they try to provide at least one blood volume (10-15 units) of 'antigen-negative' RBC units, and as many as possible beyond that. If supply is insufficient after that, they switch to antigen-positive (or untyped) units, and save a few antigen-negative units if possible for after the surgery is complete. They have had a few delayed immune responses as a consequence of the aforementioned strategy, but no acute intraoperative hemolysis attributable to the antibodies. If they do not have RBC units that lack all the antigens corresponding to a patient's antibodies, they will choose which antibodies to respect, and prioritize for antibodies which are currently present, as opposed to historical, although a past (historical) Kidd antibody would give them extra pause about the risk of delayed hemolysis. They also consider that Rh antibodies do not fix complement and are less likely to cause acute overt hemolytic reactions. If they have antigen-negative units but have reached 'massive-transfusion' status (for them that is 15 units in 24 hr), upon approval by a blood bank physician they may stop antiglobulin crossmatching. Red cell salvage is helpful if feasible.

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