Anemia and perioperative red blood cell transfusion: A matter of tolerance

Abstract

In the past, anemia in the perioperative period has been treated by red blood cell (RBC) transfusions relatively uncritically. RBC transfusions were believed to increase oxygen delivery by increasing hemoglobin concentration. Arbitrary transfusion triggers such as the "10/30 rule" (i.e., RBC transfusion indicated below a hemoglobin concentration of 10 g/dL or a hematocrit of 30%) were applied. However, there is now increasing evidence that RBC transfusions are associated with adverse outcomes and should be avoided whenever possible. Restraining from RBC transfusions and maintaining normovolemia in patients suffering from surgical blood loss results in acute anemia. Therefore, knowing the compensatory mechanisms during acute anemia is crucial. This review focuses on acute anemia tolerance, its limits, and physiologic transfusion triggers in the perioperative period.

Anemia of chronic disease: A harmful disorder or an adaptive, beneficial response?

“…Under normal circumstances, oxygen consumption in the resting human body is approximately 4 times less than oxygen delivery to the tissues. 4 Increased extraction of oxygen from the tissues, combined with a rightward shift in the oxygen-hemoglobin dissociation curve, is sufficient to maintain normal oxygen delivery in the presence of mild to moderate anemia. 5,6 Experiments designed to quantify the cardiovascular response to anemia have generally done so by the acute induction of severe anemia below 80 g/L.…”

Uludag University Medical Faculty Research Hospital Emergency Service an Epidemiological Investigation into Blood and Blood Product Transfusion

“…Transfüzyon için eşik değer olarak 7 g/dL altında bir değer kullanan çalışma olmamasına rağmen, bazı kılavuzlarda bazı hasta grupları için bu değerin, yetersiz oksijen sunumunun işaretlerinin yani hipoksinin görüldüğü düzeye kadar inmesine izin verilmiştir (28,29). Hücresel düzeydeki hipoksi ve şokun anlaşılmasında kritik oksijen sunumunun anlaşılması önemlidir.…”

Blood Tranfusion in Critically Ill Patients: State of the Art

“…This results in a shift of the oxyhemoglobin dissociation curve to the right, favoring oxygen release. 35,38 The patient's individual tolerance to anemia is one of the most important factors regarding decisions on transfusions. Thus, it is mandatory to assess the capacity of each patient to compensate for an acute decrease in hemoglobin concentration.…”

“…This means that below this threshold, any further decrease in Do 2 or Hb also results in a decrease in Vo 2 and in tissue hypoxia. 35 The concept of critical oxygen delivery (Do 2CRIT ) is important to the understanding of cellular hypoxia and shock. Tissue oxygen delivery is determined by oxygen-carrying capacity (hemoglobin concentration and the oxyhemoglobin dissociation curve) and cardiac output.…”