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  Key point 1. On average, preoperative anemia affects one in three surgical patients and is associated with worse postoperative clinical outcomes. [9/9]

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  Key point 2. Postoperative anemia affects a high proportion of patients who have major surgery with significant perioperative bleeding and is also associated with worse clinical outcomes. [9/9]

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  Key point 3. At minimum, preoperative anemia should be screened for, classified, and treated in patients who require a surgical procedure, whether elective or non-elective, in which the probability of requiring packed red blood cell transfusion (PRBCT) is >10% and/or in which bleeding >500 mL or >10% of blood volume is expected (Fig. 1). [8/9]

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  Key point 4. Patients with known anemia or anemia caused by the condition that requires surgical treatment are also candidates for inclusion in this program, even if the surgery does not entail bleeding greater than 500 mL or 10% of blood volume. [8/9]

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  Key point 5. It is debatable whether it is necessary to include patients who require a minor surgical procedure or with low bleeding risk (except in patients with additional bleeding risk factors) in this preoperative anemia study program. However, if anemia is detected in the standard preoperative evaluation, it should be studied and treated while proceeding with the surgery, although not necessarily in an optimization program. [8/9]

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  Key point 6. The presence and severity of postoperative anemia must be investigated in all patients who undergo major surgery who were anemic at the time of surgery or who had moderate to severe perioperative blood loss (Fig. 1). [8/9]

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  Key point 7. All institutions in which major surgical procedures are performed should have a protocol for the management of perioperative anemia and hematinic deficiencies. [9/9]

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  Key point 8. For surgeries in which the likelihood of PRBCT is >10% and/or in which bleeding >500 mL or >10% of blood volume is expected, preoperative anemia must be defined as Hb <13 g/dL, regardless of the patient’s sex (Fig. 1). [9/9]

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  Key point 9. For surgeries in which the likelihood of PRBCT is <10% and/or bleeding <500 mL or <10% of blood volume is expected, preoperative anemia can be defined according to WHO criteria: Hb <12 g/dL in non-pregnant women and Hb <13 g/dL in men. [9/9]

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  Key point 10. Postoperative anemia can be defined according to WHO criteria: Hb <12 g/dL in non-pregnant women and Hb <13 g/dL in men. [9/9]

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  Key point 11. In all patients scheduled for surgery with a risk of bleeding and/or transfusion, at minimum, a complete blood count with reticulocytes (and reticulocyte Hb, if available) and determination of iron parameters (iron, ferritin, transferrin, and transferrin saturation), vitamin B12, folate, creatinine (estimated glomerular filtration rate), and an inflammatory marker (C-reactive protein [CRP]) should be ordered (Fig. 2). [8/9]

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  Key point 12. In elective procedures, preoperative anemia screening and classification should be performed when the surgery is indicated or at least four weeks prior to the surgery. However, any period prior to surgery, even if it is short, is acceptable for screening for anemia and initiating treatment if necessary (Fig. 1). [8/9]

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  Key point 13. In non-elective urgent or emergency surgery patients, blood samples should be collected prior to the procedure—ideally upon admission—in order to screen for and classify anemia and initiate perioperative treatment as soon as possible (Fig. 1). [8/9]

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  Key point 14. There are different forms of iron homeostasis abnormality (Fig. 2):

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  Absolute iron deficiency: Ferritin <30 ng/mL.

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  Iron deficiency of inflammation (dual disorder): Ferritin <100 ng/mL, if transferrin saturation (TSAT) <20% or reticulocyte hemoglobin <28 pg and/or CRP > 5 mg/L.

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  Functional iron deficiency or iron sequestration (anemia of inflammation): Ferritin >100 ng/mL with TSAT < 20% and CRP > 5 mg/L

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  Low iron stores: Ferritin 30–100 ng/mL and TSAT > 20%. [8/9]

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  Key point 15. It is generally accepted that a serum vitamin B12 concentration >270 pg/mL and serum folic acid >3–5 ng/mL (depending on the laboratory) rules out deficiency of these maturation factors, but additional laboratory tests may be needed to confirm this (Fig. 2). [8/9]

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  Key point 16. The routine determination of baseline erythropoietin (Epo) levels in preoperative anemia screening is not considered cost-effective. [9/9]

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  Key point 17. The patient should be referred for the study and treatment of anemia when it is not justified by the condition which led to the surgical procedure indication, especially in cases of iron deficiency, renal failure, anemia of inflammation or of unknown origin, macrocytic anemia not justified by liver disease and/or B12/folate deficiency, or any other anemia accompanied by another cytopenia. Studying these anemias in a quick-resolution consultation is a priority in order to minimize the possible delay in surgery. [7/9]

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  Key point 18. After major surgery with significant perioperative bleeding, at least one Hb determination in the first 24 h is required. In stable patients, it is advisable to perform another determination on the third or fourth day after surgery (when the Hb nadir is reached) in order to screen for the presence of anemia and its severity as well as to initiate treatment, if necessary (Fig. 3). In patients with persistent postoperative bleeding, daily Hb monitoring is justified. [9/9]

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  Key point 19. During postoperative hospitalization, if iron deficiency is suspected and preoperative data are not available, iron deficiency should be defined as ferritin <100 ng/mL or ferritin <300 ng/mL and transferrin saturation <20%, but additional laboratory tests may be needed for confirmation, such as a reticulocyte hemoglobin <28 pg (or equivalent parameters) or a ferritin ratio (log ferritin/soluble transferrin receptor) >2, if available. [8/9]

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  Key point 20. The iron content of food is unlikely to be enough to correct anemia and replenish iron stores in a patient with iron deficiency anemia (IDA). [9/9]

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  Key point 21. Provided there is adequate tolerance and enough time (ideally six to eight weeks), oral iron salts administration can be useful for the preoperative treatment of iron deficiency and mild to moderate iron deficiency anemia (IDA) IDA as well as to replenish low iron stores (Fig. 2). [9/9]

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  Key point 22. Oral iron salts must be administered at low doses (40–50 mg of elemental iron) once daily or at moderate doses (80–100 mg of elemental iron) every other day in order to maximize absorption and improve tolerance and treatment adherence. [9/9]

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  Key point 23. After major surgery, the release of hepcidin induced by the inflammatory response to surgical aggression drastically decreases the absorption of oral iron salts, limiting their bioavailability and increasing their adverse gastrointestinal effects. Therefore, the administration of oral iron salts in the immediate postoperative period is generally not recommended. [9/9]

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  Key point 24. The absorption of oral sucrosomial® iron is mostly independent of hepcidin. The available evidence suggests the efficacy of its administration for treating IDA and perioperative iron deficiency in different surgeries (cardiac, vascular, orthopedic, bariatric, gynecological), but further studies are needed.14[8/9]

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  Key point 25. If the efficacy of oral sucrosomial® iron administration is confirmed, this could be the treatment of choice, especially in cases of refractoriness/intolerance to oral iron salts. It could be started early from primary care departments, which could reduce the prevalence of anemia and intravenous iron (FeIV) requirements in the days prior to elective surgery. [8/9]

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  Key point 26. FeIV is a safe and effective alternative to oral iron for treating perioperative iron deficiency and IDA.15 It should preferably be used in anemic patients who:

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  Have intolerance or a contraindication to oral iron, inflammation, moderate to severe anemia, or persistent bleeding.

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  Are expected to have moderate to high perioperative blood loss (>500 mL or >10% of blood volume).

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  Receive erythropoiesis-stimulating agents (ESAs)

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  Have little time before major surgery (≤4 weeks) or have developed moderate or severe postoperative anemia. [9/9]

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  Key point 27. The timing of administration, the severity of the anemia, the underlying disease, and perhaps the FeIV formulation used (high dose vs. low dose) influence treatment response.15[9/9]

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  Key point 28. Although they are becoming increasingly safe, FeIV formulations are more expensive than oral iron formulations and entail the need for venous access (adverse effects at the injection site may occur) and infusion monitoring (a risk of infusion reactions [relatively frequent] and hypersensitivity [rare] remains).15[9/9]

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  Key point 29. FeIV formulations that allow for administration of high doses (1000–1500 mg) in a single infusion (15–30 min) can facilitate treatment and be cost-effective.15[9/9]

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  Key point 30. ESAs have a role in the treatment of anemia in surgical patients in whom substantial blood loss is anticipated, especially those with anemia of inflammation, who have little time for optimization prior to surgery and in those who decline packed red blood cell transfusion (PRBCT).6,8,11 Coadjuvant treatment with IV iron is advised in order to increase the efficacy of ESAs and reduce the risk of thrombocytosis. [9/9]

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  Key point 31. All patients with a documented vitamin B12 and/or folate deficiency must be treated. The route of administration (oral or parenteral) and regimen (dose and frequency) will depend on the cause and severity of the deficiency and the associated symptoms. [9/9]

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  Key point 32. Prophylactic supplementation with oral folic acid (5 mg/day until surgery) and parenteral vitamin B12 (1 mg dose) may be useful in meeting the demands of increased erythropoietic activity during the treatment of moderate-severe anemia, especially in patients at risk of deficiencies of these maturational factors and/or those who receive ESAs.8[8/9]

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  Key point 33. PRBCT would be indicated for the treatment of severe anemia in patients with hemodynamic instability, risk criteria, and/or alarm symptoms. Although it is a useful measure in these cases, it is a limited therapeutic resource of transitory efficacy and is not without complications. [9/9]

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  Key point 34. A restrictive strategy for PRBCT (if hemoglobin concentration <7–8 g/dL and/or presence of signs or symptoms of acute anemia) has been shown to be at least as effective as a liberal strategy (if Hb <9–10 g/dL) in most inpatient studies. [9/9]

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  Key point 35. The use of “restrictive” criteria for PRBCT has been shown to be safe in most populations studied except in patients with acute cardiac ischemia or those who have undergone oncologic abdominal surgery; no conclusive data are available on these patients. [8/9]

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  Key point 36. In most hemodynamically stable patients in whom PRBCT is considered, the administration of a single unit may be a valid option. It should be remembered that the transfusion of each PRBC unit is a separate clinical decision, which makes it necessary to reevaluate the patient before prescribing the next one. [9/9]

Adequate management of perioperative anemia is one of the fundamental pillars of PBM.4,5 There are consensus documents and clinical practice guidelines developed by national and international working groups and/or scientific societies that recommend a systematic approach to treating preoperative anemia.6–11,13 Regarding postoperative anemia, most recommend the use of a restrictive threshold for PRBCT in treating severe anemia, but recommendations on pharmacological treatment are scarce or non-existent. This leads to variability in clinical practice.3,6–11,13

Based on the scientific evidence and their clinical experience, this multidisciplinary panel of professionals reached a consensus on the most important epidemiological, etiological, diagnostic, and treatment aspects related to perioperative anemia and its comprehensive management (presented as KPs). Based on the 36 KPs that were agreed upon—most of them unanimously—a pragmatic, clear, easy-to-follow clinical pathway was developed through algorithms (Figs. 1–3) for the diagnosis and treatment of perioperative anemia and hematinic deficiencies in order to improve the clinical progress and functional recovery of surgical patients and to do so in a cost-effective manner.5

To achieve this objective, close collaboration among the main departments involved (surgery, anesthesiology, hematology, internal medicine, family medicine) is essential in order to ensure continuity of care throughout the entire process, from the indication for surgery to postoperative recovery. In addition, it would be ideal to establish a multidisciplinary preoperative care clinic, such as those proposed by the Centre for Preoperative Care in the United Kingdom (https://cpoc.org.uk) or the Clinical Pathway for Intensified Recovery in Adult Surgery in Spain10 in order to develop a personalized care plan to optimize not only erythropoiesis, but also the patient’s overall health status. This care would continue during surgery and post-anesthesia recovery (surgery, anesthesia), the hospital stay on the ward (ideally in a multidisciplinary manner in shared-care programs: internal medicine, hematology), and after hospital discharge (family medicine).

In summary, this consensus document not only analyzes why, for whom, with what, and when to treat perioperative anemia, but also provides a clinical pathway on how to screen for, classify, and treat it based on the type of surgery. Therefore, it is hoped that it will be a useful tool for the development and implementation of early identification and appropriate management programs that are adapted to the available resources and particular characteristics of the different hospital institutions in Spain.

Communication presented at the 44th National Congress of the Spanish Society of Internal Medicine. Valencia, Spain. November 15–17, 2023. Award for the best type A poster.