Focus on Anemia May Alter Transfusion Practices
by Brian P. Dunleavy
New York—Blood transfusions have been among the most commonly performed invasive procedures in the United States, with a significant percentage occurring perioperatively to treat anemia.Now, there is a movement within anesthesiology to change the way anemia is managed in patients undergoing elective surgery. During a session at the 2012 PostGraduate Assembly in Anesthesiology (PGA), a panel of blood conservation specialists within the profession said that, given the risks associated with blood transfusion, it is time for a “new paradigm.”
“There is a long tradition of accepting anemia as a relatively harmless problem that can be easily corrected with transfusion,” said Aryeh Shander, MD, chief of the Departments of Anesthesiology, Critical Care Medicine, Pain Medicine and Hyperbaric Medicine at Englewood Hospital and Medical Center, in Englewood, N.J. “Transfusion for many of us is the default. That has to change.”
Studies have shown that anemia in the surgical setting is associated with significant morbidity and mortality, and the PGA panelists saw a clear need to address the condition within this patient population. However, they noted, blood transfusions carry significant risks, and too often these complications are poorly understood by clinicians—and therefore improperly explained to patients.
For example, according to session moderator Linda J. Shore-Lesserson, MD, professor of anesthesiology and chief of cardiothoracic anesthesiology at Montefiore Medical Center, in New York City, inflammatory events and infection are among the well-known risks associated with transfusion. But mortality, renal damage and lung dysfunction also may occur—some of which may be the result of the age of the blood being transfused, she said. Although the advent of citrate-phosphate-dextrose-adenine-1 has enabled blood banks to store red blood cells for up to 42 days, Dr. Shore-Lesserson said this “may be too long.”
“There is evidence that there is a linear if not geometric increase in the levels of cell lysis and oxidative injury markers as you store blood for longer periods of time,” Dr. Shore-Lesserson continued. “What is the effect clinically? If there is an effect, it is going to be difficult to measure in prospective, randomized trials. And given that in our country and in our world blood-banking procedures are really not equipped to limit the blood supply to younger units of blood, I think it’s worth taking the time to really investigate this question further. To say that you need to only transfuse units that are 14 days [old] or younger would be catastrophic [to] our blood supply and may not be worthy of the outcomes we are looking for. However, it is clear that there is morbidity associated with blood transfusion.”
Although the risk for infection—including HIV and hepatitis C—associated with transfusion is well understood, the leading cause of transfusion-related mortality in the United States is transfusion-related acute lung injury (TRALI; Table). And TRALI is “underreported and underrecognized,” said Ian J. Welsby, MD, associate professor of anesthesiology and critical care at Duke University Medical Center, in Durham, N.C.
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Avoiding Transfusions by … Transfusing
The panelists agreed that the goal for treating patients undergoing elective surgery should be to prevent transfusion without incurring risk for anemia. Another panelist, Keyvan Karkouti, MD, associate professor of anesthesiology and health policy, management, and evaluation, at the University of Toronto, Canada, has explored a possible alternative approach: prophylactic transfusion.
Dr. Karkouti and his team published a study in Anesthesiology (2012;116:613-621) that found that prophylactic transfusions of red blood cells may reduce anemia and limit the need for additional transfusions. The trial found that anemic patients—those with hemoglobin levels of 10 to 12 g/dL—undergoing cardiac surgery with cardiopulmonary bypass who received prophylactic transfusions one to two days before surgery were less likely to experience perioperative anemia and erythrocyte transfusions (P=0.0002).
Dr. Shander said Dr. Karkouti’s study indicates that when it comes to anemia, clinicians are missing an “opportunity to diagnose an underlying disease that carries significant morbidity and mortality before these patients enter the surgical arena.” Studies have found that prophylactic transfusion is used in only 25% to 50% of anemic patients who “could have been treated preemptively prior to elective surgery,” Dr. Shander added.
Dr. Shander is president of the Society for the Advancement of Blood Management, which is working with the American Society of Anesthesiologists to develop new criteria for the diagnosis and treatment of anemia in patients undergoing elective surgery and position anesthesiologists as the “gatekeepers” in the management of these patients.
“We can debate whether or not the best approach is transfusion or treatment with erythropoiesis-stimulating agents, but if the therapy is directed, correct and implemented at the right time it is the safest option for the patient,” Dr. Shander said. “Anemia is a burden that is not well defined, and part of the burden is lack of knowledge we have. Transfusion is only one treatment among many available. Preoperative detection and diagnosis of anemia reduces both the risk of transfusion as well as risks of anemia.”
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