“The inception of the preoperative anemia clinic (PAC) occurred in 2014 when I was the medical director of our Center for Blood Conservation, which serves the needs of patients who cannot be transfused, such as those of the Jehovah’s Witness faith, or others who, for moral or religious reasons, decline transfusion,” says Nicole R. Guinn, MD, MBA, Associate Professor, Anesthesiology, and Chief of Neuroanesthesiology, Otolaryngology and Offsite Anesthesia at Duke University Medical Center in Durham, North Carolina.
“We see patients when they are admitted to the hospital or before surgery. For major surgeries, we optimize them before their procedure. That means diagnosing and treating anemia and using blood conservation techniques, in addition to documenting what the patient will and will not accept. Our patients do very well during surgery and afterward, which got us thinking, ‘Why are we only doing this for these patients? All patients would benefit from this treatment.’”
That moment of reflection launched the idea of establishing the PAC, says Dr. Guinn. “Now, we get referrals either from the preoperative anesthesia and surgical screening (PASS) clinic or directly from the surgeons. We evaluate the patient’s labs to diagnose anemia and formulate treatment plans to optimize their hemoglobin before surgery to minimize transfusions, all with the hope of creating better outcomes.”
Transfusion isn’t always the answer
Many surgeons and anesthesiologists are familiar with the idea of patient blood management (PBM), which includes optimizing coagulation strategies and interdisciplinary blood conservation modalities. However, they may not be aware of how common anemia is or why it’s a problem. Some studies show that it affects 25%-75% of patients, with an increasing prevalence in the elderly (Anesthesia & Analgesia 2020:130;1364-80). In addition to being the strongest predictor of perioperative transfusion, anemia is an independent risk factor for perioperative morbidity and mortality, including acute kidney injury and cardiovascular events. When not addressed, anemia can increase the risk of postoperative complications such as myocardial infarction, stroke, and cognitive dysfunction, as well as increase length of stay, mortality, and duration of ventilator requirement (Family Med Prim Care 2022;11:5004-9).
“Time is one of the biggest factors that makes anemia management difficult. You really need at least four weeks to get the lab results, diagnose the condition, prescribe treatment, and have patients respond. We recommend patients be screened for anemia as soon as surgery is contemplated, ideally four to six weeks before surgery.”
“When anemia is diagnosed in the perioperative period, it’s often treated with transfusion as the standard treatment. While transfusion is certainly the best treatment for acute severe anemia, such as from a traumatic injury like a car accident when the patient has lost a lot of blood, it’s not necessarily the best treatment for chronic anemia, such as a patient with iron deficiency,” says Dr. Guinn who is chair of the ASA Committee on Patient Blood Management and nationally known as an expert in preoperative optimization of anemia in surgical patients. “Transfusions also carry their own risks. There is a lot of data showing that transfusion is associated with worse outcomes – infections, kidney injury, stroke, and death, to name a few.”
The default to using transfusion to treat anemia also becomes a problem when there’s not enough blood to go around. “When you’re trying to manage a scarce resource, you want to save blood products for those patients with acute, severe anemia, and not the patients with chronic anemia who are better served by figuring out why they are anemic and treating that cause.”
More transfusions of women may be occurring because of the definition of anemia. According to the World Health Organization (WHO), the current definition of anemia is hemoglobin <12 g/dL in adult nonpregnant women and <13 g/dL in adult men. However, women undergoing surgery with hemoglobin of 12 g/dL are twice as likely to be transfused as men presenting with hemoglobin of 13 g/dL (Family Med Prim Care 2022;11:5004-9).
Dr. Guinn said the case could be made for using a hemoglobin of 13 for women and men to be more consistent.
Importance of preoperative evaluation
As part of anemia management, a preoperative evaluation should occur as soon as possible so there is adequate time for intervention. The visit should look for symptoms such as hematochezia, melena, hematemesis, heavy menstrual bleeding, hematuria, hemoptysis, weight loss, history of gastrointestinal surgery, and poor nutrition. Medical history should include previous packed red cell transfusions, inherited/acquired coagulopathy, and venous thromboembolism. In addition, one should look for comorbid conditions and carefully review all prescriptions and over-the-counter drug use (Family Med Prim Care 2022;11:5004-9).
“Time is one of the biggest factors that makes anemia management difficult,” says Dr. Guinn. “You really need at least four weeks to get the lab results, diagnose the condition, prescribe treatment, and have patients respond. We recommend patients be screened for anemia as soon as surgery is contemplated, ideally four to six weeks before surgery.”
The preoperative anemia clinic at Duke considers these possible underlying etiology(s) for anemia:
- Iron deficiency
- Anemia of chronic disease/anemia of inflammation
- Vitamin B12 and folate deficiency
- Other issues such as hemoglobinopathies, hemolysis, medications, and bone marrow suppression.
Laboratory evaluation includes:
- Complete blood count
- Iron studies:
- Ferritin
- Iron, TIBC, TSAT
- Retic count, Retic-Hb.
- Folate and vitamin B12
- Creatinine
- Hemoglobin electrophoresis.
“I understand that you may not have the time to run these tests or start treatment because even with elective surgery, patients and surgeons often don’t want to delay. However, even if you can’t treat anemia before surgery, you can treat it afterward in the hospital. This may still result in improved outcomes.”
Treatment options
If time allows (e.g., at least six weeks), oral iron is the preferred treatment for preoperative anemia or iron deficiency as it is inexpensive and readily available (Anesth Analg 2002;135:532-44).
“Our preoperative anemia clinic predominately uses low molecular weight iron dextran, which is one of the lower-cost intravenous iron formulations and has been around for a long time,” says Dr. Guinn. “The disadvantage is that the infusion appointment is longer because it is given at a slower rate. Newer medications can be given as a push administration, but these cost more.
“We also use erythropoietin stimulating agents (ESAs), which stimulate bone marrow to produce more red blood cells. We recommend ESAs for treating patients who decline red cell transfusion, have moderate to severe anemia, anemia secondary to chronic kidney disease, or anemia of chronic inflammation.
“Anemia is emerging as an important modifiable risk factor, and that’s the way we should think of it going forward,” says Dr. Guinn. “Just as you wouldn’t have a patient undergo an elective surgery with a hemoglobin A1C of 13 whose diabetes is poorly controlled, anemia should be diagnosed and managed. Awareness of the consequences of anemia in the preoperative period can lead to better recognition of the condition, early management, and potentially better outcomes during surgery and afterward.”
Evidence-Based Recommendations for Managing Preoperative Anemia and Iron Deficiency in Patients Undergoing Cardiac Surgery
The Eighth Perioperative Quality Initiative (POQI 8) consensus conference, in conjunction with the Enhanced Recovery After Surgery Cardiac Surgery Society, brought together an international, multidisciplinary team of experts to review and evaluate the literature on screening, diagnosing, and managing preoperative anemia and iron deficiency in patients undergoing cardiac surgery and to provide evidence-based recommendations. The recommendations, published in September 2022, include (Anesth Analg 2022; 135:532-44):
- Screening all patients for anemia and iron deficiency as soon as surgery is contemplated
- Measurement of hemoglobin concentration as a screening tool for anemia
- Measurement of ferritin and transferrin saturation as a screening tool for iron deficiency
- Further work-up for patients identified as being anemic to determine etiology and appropriate treatment (laboratory work-up, including complete blood count, if anemia identified by point-of-care testing, creatinine, vitamin B12, folate, reticulocyte count, history and physical)
- Preoperative treatment for anemia
- Preoperative treatment of iron deficiency with or without anemia
- Treatment of iron-deficiency anemia with intravenous iron preferred over oral iron when there is limited time before surgery
- Referral for consideration of erythropoietin stimulating agent (ESA) treatment for the following patient populations: patients who decline red cell transfusion, have moderate to severe anemia, or have anemia secondary to chronic kidney disease and/or anemia of chronic inflammation
- Use of a preoperative anemia care coordination program as a cost-effective method to improve outcomes.