Anaemia is defined by the World Health Organization as a haemoglobin level below 12 g/dL in women and 13 g/dL in men. Specific thresholds apply to pregnant women and children . Anaemia prior to surgery significantly increases the risk of perioperative complications and transfusion. Managing preoperative anaemia is an important part of Patient Blood Management.
Preoperative anaemia is caused by disease, disorder or a nutritional deficit. Even mild preoperative anaemia is independently associated with increased perioperative morbidity and mortality. An underlying disease may negatively affect perioperative outcome, and furthermore preoperative anaemia significantly increases the risk of transfusion and its associated risks. A surgical procedure with a moderate or high blood loss will further aggravate the anaemia and deplete iron stores.
Early screening for preoperative anaemia is necessary to allow time for diagnostic workup and for treatment to raise the haemoglobin concentration and reduce perioperative transfusion. Anaemia should be classified and the underlying cause identified and treated, if possible. Iron deficiency anaemia is the most frequent type, e.g. caused by bleeding, diet or malabsorption. Anaemia of chronic inflammation (disease) is also frequent due to e.g. autoimmune disease or cancer, and is often seen in combination with iron deficiency. Other causes of anaemia are hematologic disease, kidney failure, B-vitamin deficiency and haemolytic conditions, and some of these will be more amenable to treatment than others.
Patients with multiple preoperative risks, such as anaemia in combination with anticoagulant treatment and a major surgical procedure may be at risk for intraoperative organ ischemia and/or massive transfusion and a complicated postoperative period. Patients, in whom anaemia diagnosis reveals severe disease, may have to have their surgery postponed or cancelled. In other cases, performing the surgery quickly may be imperative, and further anaemia management may have to be postponed. Therefore, a complete PBM plan should always include an individual risk assessment. Even though PBM should be tailored to the patient, algorithms for anaemia management prior to specific procedures such as cardiac or orthopaedic surgery is useful. See Figure in .
- definitions according to World Health Organization (WHO) .
- prevalence depends on the haemoglobin threshold.
- According to WHO limits, this increases with age to 10% of the general population above 65 years of age and >20% of above 85 years of age [4, 5].
- In the middle-aged population, anaemia is associated with cancer, heart and kidney disease, and with increased long-term mortality , even at haemoglobin concentrations well above WHO anaemia definition.
- is frequent and often previously undiagnosed, and depending on age and comorbidity, it is seen in 5-75% of the patients [7-9].
- even mild, it is a marker for disease, and associated with increased perioperative mortality and morbidity [1, 10]
- is associated with a 2-6 fold increased risk of perioperative transfusion, and postoperative anaemia [11-14]
- should be diagnosed at least 4 weeks ahead of surgery to allow time for correction of haemoglobin [7, 15]
Click on Figure to enlarge
The purpose of anaemia treatment is to raise the haemoglobin concentration before surgery. Treatment should be directed against the cause of the anaemia [7, 15]. In iron deficiency anaemia and in functional iron deficiency, haemoglobin can be raised with iron alone or in combination with erythropoiesis-stimulating agents [2, 16-18]. Iron can be administered orally, which is cheap but takes 2-3 month to work. Between 10-30% of the patients on oral iron have gastrointestinal side effects, which reduces compliance with treatment [19, 20]. Furthermore, inflammation inhibits gastrointestinal absorption and reticulo-endothelial release of iron for erythropoiesis, so tablets may not be useful in anaemia of chronic disease [20, 21]. Intravenous iron is more expensive but may increase haemoglobin levels in 2-4 weeks, depending on the pre-treatment haemoglobin level. Intravenous iron bypasses gastrointestinal absorption and can increase haemoglobin levels in patients with anaemia of chronic disease, even as a sole therapy. Side effects are few and generally mild, but rare cases of anaphylaxis are seen [20, 22], and one meta-analysis found an increase in infection rates with intravenous iron .
- The BloodSafe elearn from National Blood Authorities has very good appendices with details of iron deficiency anaemia management, including the use of the Ganzoni formula for calculation of the dose.
- When dosing iron the expected surgical blood loss should be included in the dose calculation .
- Postoperative iron deficiency or anaemia optimization may succeed in raising haemoglobin and improve fatigue and/or physical function, but transfusion rate may not be affected because of the late timing of iron treatment in relation to the timing of perioperative transfusion .
- National Blood Authorities Australia:
- Society of Thoracic Surgeons Guideline
- American Society of Anesthesiologists - Guideline on perioperative PBM: bleeding management
- Network for Advancement of Transfusion Alternatives
- Algorithm for detection, assessment and management of preoperative anaemia (Figure 2 in ) and similar in .
- Figure 1 (PBM) in  gives a quick overview of pre- intra and postoperative anaemia management and the PBM-context.
- The Perioperative module (BloodSafe) will provide guidance on how to make an outline for an individual patient PBM ahead of surgery.
(e.g. all patients admitted for a certain type of elective surgery). Secondly you need to establish if and when haemoglobin is measured (how many days or weeks before surgery). If anaemia is systematically investigated weeks prior to surgery, you can go on to measure the effect of anaemia treatment by checking haemoglobin levels immediately prior to surgery and the effect on perioperative blood transfusion.
- BloodSafe (National Blood Authorities of Australia) has set up award winning transfusion practice and PBM education:
- Anaemia working group España (e-learning in Spanish)
- The percentage of patients who gets an early haemoglobin screen 3-8 weeks before elective surgery (patients with surgery + early haemoglobin / all patients with surgery)
- The percentage of anaemic patients at the time of the screen (patients with anaemia / all patients with early haemoglobin)
- The percentage of anaemic patients just before surgery (patients with anaemia at surgery / patients with anaemia at early screen)
- If preoperative target haemoglobin is reached in treated patients
- The percentage of patients exposed to RBC transfusion (patients with surgery + transfusion / all patients with surgery)
- Number of RBC units per 1000 surgeries (activity-indexed blood utilization)
- Improved or unchanged patient safety (e.g. complications, length of stay, mortality)
- Liberal versus restrictive transfusion thresholds for patients with symptomatic coronary artery disease. Am Heart J 2013; 165:964-971.
- Alternatives to blood transfusion. Lancet 2013; 381(9880):1855-1865.
- WHO: Haemoglobins for the diagnosis of anaemia and asessment of severity Vitamins and Mineral Nutrition information system. World Health Organisation. Geneva. 2011.
- Epidemiology of anemia in older adults. Semin Hematol 2008; 45(4):210-217.
- Prevalence of anemia in persons 65 years and older in the United States: evidence for a high rate of unexplained anemia. Blood 2004; 104(8):2263-2268.
- Anemia in the general population: prevalence, clinical correlates and prognostic impact. Eur J Epidemiol 2014; 29(7):489-498.
- Detection, evaluation, and management of preoperative anaemia in the elective orthopaedic surgical patient: NATA guidelines. Br J Anaesth 2011; 106(1):13-22.
- Predicting the risk of perioperative transfusion for patients undergoing elective hepatectomy. Ann Surg 2009; 250(6):914-921.
- Detection, evaluation, and management of anemia in the elective surgical patient. Anesth Analg 2005; 101(6):1858-1861.
- Preoperative anaemia and postoperative outcomes in non-cardiac surgery: a retrospective cohort study. Lancet 2011; 378(9800):1396-1407.
- The prevalence and association with transfusion, intensive care unit stay and mortality of pre-operative anaemia in a cohort of cardiac surgery patients. Anaesthesia 2011; 66(9):812-818.
- Preoperative anaemia is associated with poor clinical outcome in non-cardiac surgery patients. Br J Anaesth 2014; 113(3):416-423.
- Role of preoperative anemia for risk of transfusion and postoperative morbidity in fast-track hip and knee arthroplasty. Transfusion 2014; 54(3):717-726.
- The risks of red cell transfusion for hip fracture surgery in the elderly. Vox Sang 2012; 103(3):223-230.
- National Blood Authorities of Australia-Patient Blood Management Guidelines 2013
- Safety and usefulness of intravenous iron sucrose in the management of preoperative anemia in patients with menorrhagia: a phase IV, open-label, prospective, randomized study. Acta Haematol 2009; 121(1):37-41.
- Blood transfusion reduction with intravenous iron in gynecologic cancer patients receiving chemotherapy. Gynecol Oncol 2010; 116(3):522-525.
- The feasibility and clinical efficacy of intravenous iron administration for preoperative anaemia in patients with colorectal cancer. Colorectal Dis 2014; 16(10):794-800.
- Iron replacement therapy in inflammatory bowel disease patients with iron deficiency anemia: a systematic review and meta-analysis. J Crohns Colitis 2012; 6(3):267-275.
- Parenteral versus oral iron therapy for adults and children with chronic kidney disease. Cochrane Database Syst Rev 2012; 1:CD007857.
- Perioperative anemia management in colorectal cancer patients: a pragmatic approach. World J Gastroenterol 2014; 20(8):1972-1985.
- The safety of intravenous iron preparations: systematic review and meta-analysis. Mayo Clin Proc 2015; 90(1):12-23.
- Safety and efficacy of intravenous iron therapy in reducing requirement for allogeneic blood transfusion: systematic review and meta-analysis of randomised clinical trials. BMJ 2013; 347:f4822.
- Efficacy and safety of intravenous iron therapy as an alternative/adjunct to allogeneic blood transfusion. Vox Sang 2008; 94(3):172-183.
- Randomized trial comparing ferric carboxymaltose vs oral ferrous glycine sulphate for postoperative anaemia after total knee arthroplasty. Br J Anaesth 2014; 113(3):402-409.
- 2011 update to the Society of Thoracic Surgeons and the Society of Cardiovascular Anesthesiologists blood conservation clinical practice guidelines. Ann Thorac Surg 2011; 91(3):944-982.
- Practice guidelines for perioperative blood management: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management* Anesthesiology 2015; 122(2):241-275.
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