Blood transfusions (BT), autologous or allogeneic, have been the common therapeutic intervention for treating perioperative anemia and surgical blood loss. In the case of allogeneic blood transfusion, there are a number of substantial risks for the blood recipient, including transmission of infectious diseases, as patients are potentially exposed to bacteria, parasites and viruses. Countries with more advanced healthcare systems, such as the US, have implemented thorough testing of allogeneic blood products, which reduced allogeneic blood transfusion (ABT)-transmitted viruses to very low levels. However, transfusion-related acute lung injury, hemolytic transfusion reactions, and transfusion-associated sepsis became the leading causes of ABT-related mortality.1 In addition, ABT can still transmit lethal infections due to novel pathogens.2 For these reasons, effective perioperative blood management (PBM) strategies are crucial to minimize allogeneic blood transfusions. There are generally three modes for perioperative blood management: preoperative, intraoperative and postoperative.
Preoperative blood management includes:
1) Detecting and correcting abnormalities in hematological homeostasis. For instance, looking for abnormal bleeding tendencies in the past, prior BTs, thrombotic events, intake of drugs that can adversely affect bleeding etc.
2) Preparing for autologous blood donation. For patients that are scheduled for elective procedures in which they are likely to receive transfusion, they can store one unit of blood per week for a month prior to their operation, to be transfused back into the same patient.3
Intraoperative blood management generally focuses on reducing blood loss and/or collection and reinfusion of the patient’s own blood.3 Strategies include:
1) Positioning. The surgical position of the patient can significantly influence intraoperative bleeding.
2) Ventilation. Positive pressure ventilation under general anesthesia can hamper venous return.
3) Surgical technique.
4) Maintenance of normal body temperature. Even mild hypothermia (<1oC) increases blood loss by approximately 16%.4
5) Deliberate hypotensive techniques/drugs to reduce arterial pressure.
6) Cell salvage (CS). CS is used in surgeries that result in large anticipated blood loss. CS involves collecting shed blood, processing it and re-infusing autologous red cells lost during surgery. One of the major drawbacks on this procedure is its high cost and the need for trained operators.
Lastly, postoperative blood management is often a continuation of strategies used in the intraoperative period. In conjunction with blood management strategies, patient monitoring during and after surgery is also crucial for avoiding allogeneic blood transfusion. This strategy consists of monitoring for perfusion of vital organs, blood loss, anemia, and coagulopathy using point-of-care (POC) tests since they allow for smaller volumes of blood to be used to obtain the desired laboratory parameter.5
All these techniques have been safely used in certain situations and form the basis of an integral strategy to avoid allogeneic blood transfusions. Ultimately, the combination of these techniques needs to be evaluated for individual patients on a case-by-case basis in order to achieve the lowest surgical risk.
References
[1] Vamvakas EC, Blajchman MA. Transfusion-related mortality: the ongoing risks of allogeneic blood transfusion and the available strategies for their prevention. Blood. 2009;113(15):3406-3417.
[2] Pealer LN, Marfin AA, Petersen LR, et al. Transmission of West Nile virus through blood transfusion in the United States in 2002. N Engl J Med. 2003;349(13):1236-1245.
[3] Spahn DR, Casutt M. Eliminating blood transfusions: new aspects and perspectives. Anesthesiology. 2000;93(1):242-255.
[4] Schmied H, Kurz A, Sessler DI, Kozek S, Reiter A. Mild hypothermia increases blood loss and transfusion requirements during total hip arthroplasty. Lancet. 1996;347(8997):289-292.
[5] AuBuchon JP, Puca K, Saxena S, Shulman IA, Waters JH. Getting Started in Patient Blood Management. American Association of Blood Banks. 2011.
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