Routine use of saline washed RBCs for patients undergoing cardiac surgery

A blood banker located at an East Coast hospital reports that their cardiac surgeons have begun to request that all units of red blood cells (RBCs) used by post cardiac surgery patients be saline washed prior to transfusion in the surgical ICU. Currently, in the OR, cardiac surgery patients are receiving autologous intraoperative red cells (which are saline washed) and the perfusionists are also saline washing each RBC unit that is brought into the OR from the blood bank, prior to the RBC units being transfused. The surgeons want to extend the use of washed RBC to all transfusions of cardiac surgery patients, using the autotransfusion device. According to the surgeons, the reason for the request is to reduce the amount of potassium and artifact in the aging red cell product. Three journal articles were provided to the blood bank from the surgeons to justify their request:

1. Washing of stored red blood cells by an autotransfusion device before transfusion. Vox Sanguinis, Volume 92, Issue 2, 2007, pages 130–135.
2. Processing of stored packed red blood cells using autotransfusion devices decreases potassium and microaggregates: a prospective, randomized, single-blinded in vitro study. Transfusion Medicine 2007, Volume 17 Issue 2, Pages 89 - 95.
3. Intraoperative Washing of Long-Stored Packed Red Blood Cells by Using an Autotransfusion Device Prevents Hyperkalemia, Anesth Analg 2002;95:324-325.

The inquiring colleague comments that have had a preliminary meeting to discuss the logistics of the above request. The perfusion manager contacted the AABB and was given the suggestion to include the physicians and staff who work in the ICU when defining the policy. They are also discussing labeling, documentation, and expiration times. The inquiring colleague wonders if this practice being done elsewhere.

The following comments have been submitted.

ADDENDA Dec. 29, 2009

1. Dr. Neil Blumberg, Professor of Pathology & Laboratory Medicine, Director, Clinical Laboratories, Strong Memorial Hospital, Director, Transfusion Medicine/Blood Bank at the University of Rochester Medical Center (attribution used with permission) comments that with regard to washed transfusions, as a proponent of the theory that removing stored supernatant might improve clinical outcomes, he is certainly predisposed to think that the use of washed red cells is moving in the right direction. However, he acknowledges that the only evidence for improved outcomes with washed transfusions is in patients with acute leukemia, and probably only in patients < 50 years of age:

   Blumberg N, Heal JM, Rowe JM. A randomized trial of washed red blood cell and platelet transfusions in adult acute leukemia. BMC Blood Disord. 2004 Dec 10;4(1):6.

   While it is possible washing may reduce morbidity and mortality in cardiac surgery or other settings, that line of thinking is a hypothesis/educated guess just now. Dr. Blumberg and his group have underway a randomized trial of washed transfusions in the pediatric cardiac surgery setting, led by Dr. Jill Cholette, a pediatric intensivist:

   Clinical Study: Washed Versus Standard Blood Cell Transfusions in Pediatric Open Heart Surgery

Thus the first question that Dr. Blumberg would ask is why not perform the washed red cell transfusions as a randomized trial, so that data can be collected to see if that approach is beneficial over standard therapy, and whether it might help the rest of us caring for similar patients.

If they have neither the patient volume, resources nor the mental will to conduct such a study, the next question that Dr. Blumberg would ask is whether they are doing easier, more proven things to reduce morbidity and mortality due to transfusion, as a first priority. Are they using leukoreduced blood products for all of their transfusions in their institution, so no cardiac surgery patient ever receives a non-leukoreduced transfusion? There is compelling, definitive evidence that using leukoreduced blood products reduces morbidity and mortality in the cardiac surgery setting, and universal leukoreduction of blood products should be a priority, in his opinion. The other compelling opportunity is that if they are transfusing, say 40-80% of their patients, getting that proportion down to 5-20% should be a priority. Transfusion is generally associated with dose related adverse outcomes, and finding ways of reducing who gets blood and how much is more important than whether it is washed or not in his view. Even washed, leukoreduced red cells are likely to be worse for outcomes than no transfusions.

Assuming their practices are all cutting edge (a minority of patients being transfused, all transfusions leukoreduced), the next question would be are they still transfusing a lot of FFP/FP24 and platelets? At some centers, 30-50% of patients in cardiac surgery receive platelet transfusions, a practice that is, to his mind, likely contributing significantly to increased morbidity and mortality, and providing little to no benefit. If they are transfusing platelets, are they giving them as infrequently as possible (<10% of patients), and are they planning on washing the platelets as well as the red cells? It's hard for Dr. Blumberg to conceive that washing red cells alone, yet giving unwashed platelets is going to do much to benefit these patients. Some of the evil "humours" we're guessing are in stored red cells are certainly in stored platelets as well, and possibly in FFP. So the problems could be pretty complex and not readily addressable by washing.

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