Anemia is a potent risk factor for mortality and morbidity in surgical patients, and its management has begun to shift away from allogeneic blood transfusion in recent years. This article reviews the clinical importance of perioperative anemia, the role and shortcomings of blood transfusion, and the pros and cons of alternative approaches to managing perioperative anemia. I conclude with an overview of a program for perioperative blood product use at my institution, Cleveland Clinic.
SIGNIFICANCE OF PERIOPERATIVE ANEMIA
Prevalence depends on many factors
The reported prevalence of anemia in surgical patients varies widely—from 5% to 76% 1—and depends on the patient’s disease and comorbidities, the surgical procedure and associated blood loss, and the definition of anemia used. The prevalence of preoperative anemia increases with patient age and is higher in women than in men. 2
A multiplier of risk
Anemia is an important multiplier of mortality risk. For example, the presence of anemia raises the relative risk of 2-year mortality from 2.05 to 3.37 in patients with chronic kidney disease, from 2.86 to 3.78 in patients with heart failure, and from 4.86 to 6.07 in patients with concomitant heart failure and chronic kidney disease. 3
Adverse effects of anemia have been demonstrated specifically in the perioperative setting as well. A large retrospective cohort study showed that a preoperative hemoglobin concentration of less than 6 g/dL increases the risk of death 30 days after surgery by a factor of 26 relative to a concentration of 12 g/dL or greater in surgical patients who declined blood transfusion for religious reasons. 4 The anemia-associated mortality risk was especially pronounced among patients with cardiovascular disease. 4 Other studies have demonstrated perioperative anemia to be associated with increases in the risk of death, 5 cardiac events, 6 pneumonia, 7 and postoperative delirium. 8
IS BLOOD TRANSFUSION THE ANSWER
The use of allogeneic blood transfusion to manage anemia and blood loss is a concept that originated several centuries ago and has changed little over the years.
Blood supply challenges
Blood collection has historically lagged demand, resulting in a blood supply insufficient to meet transfusion needs. According to the federal government’s 2007 National Blood Collection and Utilization Survey Report, 6.89% of US hospitals reported that they cancelled elective surgery on 1 or more days in the prior year because of a lack of blood availability, and 13.5% experienced at least 1 day in which nonsurgical blood needs could not be met. 9 Unless practices are changed to increase blood donation, these unmet tranfusion needs may grow.
Joint Commission set to measure blood management
In response to this challenge, an advisory panel formed by the Joint Commission has identified 17 performance measures related to blood conservation and appropriate transfusion. 10 These measures are currently in development, and we expect to see some types of metrics in the near future. Such metrics are likely to further prioritize blood management for US hospitals.
Safety of the blood supply: Viral transmission down, TRALI risk persists
The safety of the blood supply has improved markedly. Sophisticated testing and public demand have led to a dramatic decline in the risk of transfusion-related transmission of HIV, hepatitis C virus, and hepatitis B virus. 11