Anemia is a significant risk for morbidity and mortality in surgical patients. That risk depends on the patient’s comorbidities, type of surgery planned, and the severity, stability, and etiology of the anemia. The prevalence of baseline anemia varies in different surgical populations, with anemia present in >30% of noncardiac surgery patients, 46% of colorectal surgeries, and approximately 35% of hip and knee surgeries.1 Even mild anemia, with an approximate hemoglobin of <13 g/dl in men and <12 g/dl in women, is associated with adverse perioperative outcomes.2 In addition to the risk of mortality, perioperative anemia is associated with an increased risk of pulmonary, wound, and thromboembolic complications.
Although it is possible to treat perioperative anemia with a transfusion of packed red blood cells (PRBCs), this is associated with a myriad of complications. Allogeneic PRBC transfusion is associated with transfusion-related acute lung injury, acute hemolytic transfusion reactions, increased risk of infections, allergic reactions, transfusion-related immunomodulation, and transfusion-associated circulatory overload.3,4 These risks are relatively low overall, but transfusion is avoidable in some cases. In addition, increased exposure to allogeneic blood transfusions may increase antibody production and make subsequent transfusion or transplantation more difficult. Transfusion is also associated with mortality. In a study of cardiac surgical patients, transfusion of red cells was associated with an odds ratio for mortality of 1.18 per unit of blood transfused.5 Transfusion is also associated with increased cost of care.3
Almost 70% of PRBC units are transfused to surgical patients, and a preoperative blood management protocol may decrease the rates and risks of transfusion.1
When the timeframe to surgery permits, it is useful to evaluate appropriate patients for anemia, and if present, make efforts to treat anemia to decrease the risks associated with anemia and perioperative transfusion.
PREOPERATIVE EVALUATION/RISK FACTORS
Patient risk factors for anemia and excessive bleeding should be considered during the preoperative evaluation. These include conditions such as anemia history, liver disease, age, and other hematologic disorders.6
Preoperative evaluation with respect to anemia and blood management should include a review of medical records/laboratories, a patient interview and physical exam, and ordering of additional required tests. Specific history that is useful includes history or symptoms of anemia, previous blood transfusions, coagulopathies (heritable or drug-induced), thrombotic history, and risks for organ ischemia (coronary artery disease, renal disease, etc.).
Testing for abnormal hemoglobin levels in preoperative patients should be targeted to identify patients at risk of anemia and blood loss, while decreasing wasteful testing in patients at lower risk. For patients who receive selected testing, over half have abnormal findings, while significantly fewer are abnormal when routine or unselected testing is performed.6 Preoperative hemoglobin levels are indicated for patients scheduled to undergo procedures with ...