Perioperative medicine training resources: U3M12: Optimisation of Patients with iron deficiency, anaemia and blood product refusal

Abstract
Anaemia is a common finding in patients presenting for major elective surgery and is associated with poor outcomes including death and complications. Iron deficiency is the leading cause of perioperative anaemia. Intravenous (i.v.) iron is considered to be an effective and safe treatment for iron deficiency anaemia and is recommended by expert opinion for treatment of preoperative anaemia, although evidence from clinical trials is lacking. The PREVENTT trial was a large multicentre trial investigating the effects of i.v. iron on red cell transfusion, death, complications and quality of life in 487 patients undergoing major abdominal surgery. The principal finding of this multicentre randomised placebo controlled trial was that there was no difference in the co-primary outcomes of blood transfusion or death, or the number of transfusion episodes, within 30 days after surgery, in patients that received preoperative i.v. iron therapy compared to placebo. The major inferential differences in this independent discussion relate to the limitations of the PREVENTT trial and its implications for future practice. Although PREVENTT represents the best evidence available to guide perioperative use of i.v. iron, it is likely that the study was underpowered. In the context of already widespread adoption of preoperative i.v. iron therapy, many clinicians may have felt they lacked equipoise. In light of the PREVENTT study routine use of i.v. iron in patients undergoing elective abdominal surgery cannot be recommended. Further research should define the optimum red cell transfusion strategy for patients undergoing surgery and idenify other surgical groups who may benefit from this intervention.

Abstract
Objectives: To determine whether a multidisciplinary, multimodal Patient Blood Management (PBM) program for patients undergoing surgery is effective in reducing perioperative complication rate, and thereby is effective in improving clinical outcome.

Background: PBM is a medical concept with the focus on a comprehensive anemia management, to minimize iatrogenic (unnecessary) blood loss, and to harness and optimize patient-specific physiological tolerance of anemia.

Methods: A systematic review and meta-analysis was performed. Eligible studies had to address each of the 3 PBM pillars with at least 1 measure per pillar, for example, preoperative anemia management plus cell salvage plus rational transfusion strategy. The study protocol has been registered with PROSPERO (CRD42017079217).

Results: Seventeen studies comprising 235,779 surgical patients were included in this meta-analysis (100,886 pre-PBM group and 134,893 PBM group). Implementation of PBM significantly reduced transfusion rates by 39% [risk ratio (RR) 0.61, 95% confidence interval (CI) 0.55-0.68, P < 0.00001], 0.43 red blood cell units per patient (mean difference -0.43, 95% CI -0.54 to -0.31, P < 0.00001), hospital length of stay (mean difference -0.45, 95% CI -0.65 to -0.25, P < 0,00001), total number of complications (RR 0.80, 95% CI 0.74-0.88, P <0.00001), and mortality rate (RR 0.89, 95% CI 0.80-0.98, P = 0.02).

Conclusions: Overall, a comprehensive PBM program addressing all 3 PBM pillars is associated with reduced transfusion need of red blood cell units, lower complication and mortality rate, and thereby improving clinical outcome. Thus, this first meta-analysis investigating a multimodal approach should motivate all executives and health care providers to support further PBM activities.

Abstract
Importance: Although iron deficiency is common, it remains unclear which iron repletion strategy is associated with the lowest rate of infusion-related adverse events, and how patients with history of infusion reaction should be managed.

Objective: To evaluate rates of infusion reactions among 4 commonly used intravenous iron repletion strategies and determine how readministration was managed in patients with history of reaction.

Design, setting, and participants: This cohort study included all patients receiving intravenous iron infusion from January 1, 2015, to September 7, 2021, at 6 centers in Portland, Oregon. Participants included a total of 12 237 patients with iron deficiency, not restricted by etiology. Statistical analysis was performed from September to October 2021.

Exposures: Type of intravenous iron formulation and concurrent administration of diphenhydramine, epinephrine, famotidine, and/or hydrocortisone, used as surrogate maker of infusion reaction.

Main outcomes and measures: Incidence of adverse events, including severe events requiring epinephrine, stratified by type of iron formulation, and in patients who received premedication or with history of infusion-related reaction receiving subsequent doses.

Results: Among 35 737 unique iron infusions (12 237 patients [9480 (77.5%) women; 717 (5.9%) Black; 10 250 (83.7%) White; mean (SD) age of 51 (20) years]), comprising 22 309 iron sucrose doses, 9067 iron dextran total doses (1771 preceded by test dose, 56 test doses alone), 3147 ferumoxytol doses, and 1214 ferric carboxymaltose doses, incidence of adverse events was 3.9% (n = 1389; 95% CI, 3.7%-4.1%). Rate of infusion events differed among iron formulations: 4.3% (n = 970; 95% CI, 4.1%-4.6%) iron sucrose, 3.8% (n = 345, 95% CI: 3.4%-4.2%) iron dextran (test and full doses or test dose alone), 1.8% (n = 57; 95% CI, 1.4%-2.3%) ferumoxytol, and 1.4% (n = 17, 95% CI, 0.8%-2.3%) ferric carboxymaltose (P < .001). Severe adverse events were exceedingly rare with only 2 documented epinephrine administrations, both associated with iron dextran. Incidence of adverse events among those who received premedication was 23-fold higher compared with those who did not (38.6% vs 1.7%, χ21 = 7324.8; P < .001). Among 873 patients with history of infusion reaction who underwent readministration, the majority received the same formulation, which was associated with significantly higher reaction rate particularly if premedication was administered (68% [95% CI, 64%-72%] vs 32% [95% CI, 26%-41%], respectively), compared with those who received an alternate formulation (21% [95% CI, 11%-35%] vs 5% [95% CI, 2%-12%], respectively) (P < .001).

Conclusions and relevance: These data, and the preponderance of published evidence, suggest that intravenous iron is generally well tolerated with exceedingly low risk of severe reaction, use of premedication and test doses are unnecessary, and that optimal prevention and management of infusion-related reactions warrant further study.

Abstract
Anaemia is common before cardiac surgery and is associated with increased morbidity and mortality. The World Health Organization (WHO) definition of anaemia is lower for women than for men by 10 g.l-1 , potentially putting women at a disadvantage compared with men with regard to pre-operative optimisation. Our hypothesis was that women with borderline anaemia (defined by us as haemoglobin concentration 120-129 g.l-1 ) would have a higher rate of red cell transfusion, morbidity and mortality than non-anaemic women (haemoglobin ≥ 130 g.l-1 ). This retrospective observational study included all adult patients admitted for elective cardiac surgery from January 2013 to April 2016. During the study period, 1388 women underwent cardiac surgery. Pre-operatively, 333 (24%) had a haemoglobin level < 120 g.l-1 ; 408 (29%) 120-129 g.l-1 ; and 647 (47%) ≥ 130 g.l-1 . Compared with non-anaemic women, women with borderline anaemia were more likely to be transfused (68.6% vs. 44.5%; RR 1.5, 95%CI 1.4-1.7; p < 0.0001) and were transfused with more units of red cells, mean (SD) 1.8 (2.8) vs. 1.3 (3.0); p < 0.0001. Hospital length of stay was significantly longer in the borderline anaemia group compared with non-anaemic women, median (IQR [range]) 8 (6-12 [3-45]) vs. 7 (6-11 [4-60]); p = 0.0159. Short- and long-term postoperative survival was comparable in both groups. Borderline anaemia is associated with increased red cell transfusion and prolonged hospital stay. Future research should address whether correction of borderline anaemia results in improved outcomes.

Abstract
Pre-operative anaemia and perioperative red blood cell transfusion carry significant consequence when it comes to surgical outcomes. The establishment of patient-centred clinical pathways has been designed to harness and endorse good transfusion practice, termed the three pillars of patient blood management (PBM). These focus on the timely and appropriate management of anaemia, prevention of blood loss and restrictive transfusion where appropriate. This article reviews the current evidence and ongoing research in the field of PBM in surgery. Strategies to implement PBM have shown significant benefits in appropriate transfusion practice, reduced costs and improved length of hospital stay. Recently published national quality standards have recognised the features of the PBM blueprint such as the consideration of alternatives to red blood cell transfusion, the active measures to reduce perioperative blood loss and the appropriate management of post-operative anaemia. Adopting PBM in surgical patients should be paramount to reduce the risks posed by perioperative anaemia and blood transfusions. The principles of PBM help structure the interventions and decisions relating to anaemia and blood transfusion, but, more importantly, represent a paradigm shift towards a more considered approach to blood transfusion, acknowledging its risks, preventatives and alternatives.

Abstract
Background: The management of perioperative iron deficiency is a component of the concept of patient blood management. The objective of this study was to update French data on the prevalence of iron deficiency in patients scheduled for major surgery.

Methods: The CARENFER PBM study was a prospective cross-sectional study in 46 centers specialized in orthopedic, cardiac, urologic/abdominal, or gynecological surgery. The primary end point was the prevalence of iron deficiency at the time of surgery (D-1/D0) defined as serum ferritin <100 µg/L and/or transferrin saturation (TSAT) <20%.

Results: A total of 1494 patients (mean age, 65.7 years; women, 49.3%) were included from July 20, 2021 to January 3, 2022. The prevalence of iron deficiency in the 1494 patients at D-1/D0 was 47.0% (95% confidence interval [CI], 44.5-49.5). At 30 days after surgery, the prevalence of iron deficiency was 45.0% (95% CI, 42.0-48.0) in the 1085 patients with available data. The percentage of patients with anemia and/or iron deficiency increased from 53.6% at D-1/D0 to 71.3% at D30 ( P < .0001), mainly due to the increase of patients with both anemia and iron deficiency (from 12.2% at D-1/D0 to 32.4% at D30; P < .0001). However, a treatment of anemia and/or iron deficiency was administered preoperatively to only 7.7% of patients and postoperatively to 21.7% (intravenous iron, 14.2%).

Conclusions: Iron deficiency was present in half of patients scheduled for major surgery. However, few treatments to correct iron deficiency were implemented preoperatively or postoperatively. There is an urgent need for action to improve these outcomes, including better patient blood management.

Keywords: anemia; bleeding; blood conservation; blood transfusion; cardiac surgery; patient blood management.

Abstract
Background: Preoperative anemia is associated with increased morbidity, mortality, and risk of transfusion. Treatment through a preoperative anemia clinic (PAC) may improve outcomes.

Study design and methods: Adult patients undergoing elective orthopedic and gynecologic surgery with preoperative anemia were identified and referred for hemoglobin optimization with iron and/or erythropoietin from a single-site academic health center. Treated patients were propensity matched to untreated controls and compared on outcomes of erythrocyte transfusion, length of stay (LOS), and readmission. Changes in hemoglobin relative to treatment time before surgery were also measured in the treated cohort.

Results: One thousand three hundred thirty-two patients were evaluated between July 2015 and March 2021, of which 161 underwent optimization through the PAC. After propensity matching, 127 (98 orthopedic and 29 gynecology) PAC-treated patients were compared to 127 (98 orthopedic and 29 gynecology) control patients who did not undergo treatment. The primary outcome of perioperative transfusion was significantly lower in treated patients compared with matched controls (12.60% vs. 26.77%, p = .005). A lower LOS was demonstrated in the gynecologic PAC subgroup (2.2 [1.5, 2.4] vs. 3.1 [2.2, 3.4], p = .002). Each day of treatment time before surgery was associated with an increase of 0.040 g/dL hemoglobin (p < .001) until 65 days, after which further time did not increase hemoglobin.

Conclusion: Treatment through a preoperative anemia clinic is associated with a reduction in perioperative transfusion and possible reduction in LOS and readmission compared with matched controls. Additionally, treatment time before surgery is correlated with a greater increase in hemoglobin up until 2 months prior to surgery.

Keywords: Blood management; RBC transfusion; transfusion practices (adult).

Abstract
Treatment of anemia is one of the four pillars of patient blood management programs. Preoperative anemia is common and associated with increased perioperative morbidity after surgery and increased rates of blood transfusion. Effective treatment of preoperative anemia, however, requires advanced screening, diagnosis, and initiation of therapy weeks before elective surgery. Here we describe the development and implementation of a preoperative anemia screening and treatment program at Duke University Hospital.

Abstract
The Centre for Perioperative Care (CPOC) has published in September 2022 guidance addressing perioperative anaemia. This editorial addresses the definition of anaemia for women and management of borderline anaemia in women. We also address implications of the CPOC guidance for anaesthetists and the future direction of anaemia research and management.

Abstract
Background: Approximately 30% of adults undergoing non-cardiac surgery suffer from preoperative anaemia. Preoperative anaemia is a risk factor for mortality and adverse outcomes in different surgical specialties and is frequently the reason for blood transfusion. The most common causes are renal, chronic diseases, and iron deficiency. International guidelines recommend that the cause of anaemia guide preoperative anaemia treatment. Recombinant human erythropoietin (rHuEPO) with iron supplementation has frequently been used to increase preoperative haemoglobin concentrations in patients in order to avoid the need for perioperative allogeneic red blood cell (RBC) transfusion.

Objectives: To evaluate the efficacy of preoperative rHuEPO therapy (subcutaneous or parenteral) with iron (enteral or parenteral) in reducing the need for allogeneic RBC transfusions in preoperatively anaemic adults undergoing non-cardiac surgery.

Search methods: We searched CENTRAL, Ovid MEDLINE(R), Ovid Embase, ISI Web of Science: SCI-EXPANDED and CPCI-S, and clinical trial registries WHO ICTRP and ClinicalTrials.gov on 29 August 2019.

Selection criteria: We included all randomized controlled trials (RCTs) that compared preoperative rHuEPO + iron therapy to control treatment (placebo, no treatment, or standard of care with or without iron) for preoperatively anaemic adults undergoing non-cardiac surgery. We used the World Health Organization (WHO) definition of anaemia: haemoglobin concentration (g/dL) less than 13 g/dL for males, and 12 g/dL for non-pregnant females (decision of inclusion based on mean haemoglobin concentration). We defined two subgroups of rHuEPO dosage: 'low' for 150 to 300 international units (IU)/kg body weight, and 'high' for 500 to 600 IU/kg body weight.

Data collection and analysis: Two review authors collected data from the included studies. Our primary outcome was the need for RBC transfusion (no autologous transfusion, fresh frozen plasma or platelets), measured in transfused participants during surgery (intraoperative) and up to five days after surgery. Secondary outcomes of interest were: haemoglobin concentration (directly before surgery), number of RBC units (where one unit contains 250 to 450 mL) transfused per participant (intraoperative and up to five days after surgery), mortality (within 30 days after surgery), length of hospital stay, and adverse events (e.g. renal dysfunction, thromboembolism, hypertension, allergic reaction, headache, fever, constipation).

Main results: Most of the included trials were in orthopaedic, gastrointestinal, and gynaecological surgery and included participants with mild and moderate preoperative anaemia (haemoglobin from 10 to 12 g/dL). The duration of preoperative rHuEPO treatment varied across the trials, ranging from once a week to daily or a 5-to-10-day period, and in one trial preoperative rHuEPO was given on the morning of surgery and for five days postoperatively. We included 12 trials (participants = 1880) in the quantitative analysis of the need for RBC transfusion following preoperative treatment with rHuEPO + iron to correct preoperative anaemia in non-cardiac surgery; two studies were multiarmed trials with two different dose regimens. Preoperative rHuEPO + iron given to anaemic adults reduced the need RBC transfusion (risk ratio (RR) 0.55, 95% confidence interval (CI) 0.38 to 0.80; participants = 1880; studies = 12; I2 = 84%; moderate-quality evidence due to inconsistency). This analysis suggests that on average, the combined administration of rHuEPO + iron will mean 231 fewer individuals will need transfusion for every 1000 individuals compared to the control group. Preoperative high-dose rHuEPO + iron given to anaemic adults increased the haemoglobin concentration (mean difference (MD) 1.87 g/dL, 95% CI 1.26 to 2.49; participants = 852; studies = 3; I2 = 89%; low-quality evidence due to inconsistency and risk of bias) but not low-dose rHuEPO + iron (MD 0.11 g/dL, 95% CI -0.46 to 0.69; participants = 334; studies = 4; I2 = 69%; low-quality evidence due to inconsistency and risk of bias). There was probably little or no difference in the number of RBC units when rHuEPO + iron was given preoperatively (MD -0.09, 95% CI -0.23 to 0.05; participants = 1420; studies = 6; I2 = 2%; moderate-quality evidence due to imprecision). There was probably little or no difference in the risk of mortality within 30 days of surgery (RR 1.19, 95% CI 0.39 to 3.63; participants = 230; studies = 2; I2 = 0%; moderate-quality evidence due to imprecision) or of adverse events including local rash, fever, constipation, or transient hypertension (RR 0.93, 95% CI 0.68 to 1.28; participants = 1722; studies = 10; I2 = 0%; moderate-quality evidence due to imprecision). The administration of rHuEPO + iron before non-cardiac surgery did not clearly reduce the length of hospital stay of preoperative anaemic adults (MD -1.07, 95% CI -4.12 to 1.98; participants = 293; studies = 3; I2 = 87%; low-quality evidence due to inconsistency and imprecision).

Authors' conclusions: Moderate-quality evidence suggests that preoperative rHuEPO + iron therapy for anaemic adults prior to non-cardiac surgery reduces the need for RBC transfusion and, when given at higher doses, increases the haemoglobin concentration preoperatively. The administration of rHuEPO + iron treatment did not decrease the mean number of units of RBC transfused per patient. There were no important differences in the risk of adverse events or mortality within 30 days, nor in length of hospital stay. Further, well-designed, adequately powered RCTs are required to estimate the impact of this combined treatment more precisely.

Abstract
The use of cell salvage is recommended when it can be expected to reduce the likelihood of allogeneic (donor) red cell transfusion and/or severe postoperative anaemia. We support and encourage a continued increase in the appropriate use of peri-operative cell salvage and we recommend that it should be available for immediate use 24 h a day in any hospital undertaking surgery where blood loss is a recognised potential complication (other than minor/day case procedures).

Abstract
Background: Patient blood management (PBM) programs are associated with improved patient outcomes, reduced transfusions and costs. In 2008, the Western Australia Department of Health initiated a comprehensive health-system-wide PBM program. This study assesses program outcomes.

Study design and methods: This was a retrospective study of 605,046 patients admitted to four major adult tertiary-care hospitals between July 2008 and June 2014. Outcome measures were red blood cell (RBC), fresh-frozen plasma (FFP), and platelet units transfused; single-unit RBC transfusions; pretransfusion hemoglobin levels; elective surgery patients anemic at admission; product and activity-based costs of transfusion; in-hospital mortality; length of stay; 28-day all-cause emergency readmissions; and hospital-acquired complications.

Results: Comparing final year with baseline, units of RBCs, FFP, and platelets transfused per admission decreased 41% (p < 0.001), representing a saving of AU$18,507,092 (US$18,078,258) and between AU$80 million and AU$100 million (US$78 million and US$97 million) estimated activity-based savings. Mean pretransfusion hemoglobin levels decreased 7.9 g/dL to 7.3 g/dL (p < 0.001), and anemic elective surgery admissions decreased 20.8% to 14.4% (p = 0.001). Single-unit RBC transfusions increased from 33.3% to 63.7% (p < 0.001). There were risk-adjusted reductions in hospital mortality (odds ratio [OR], 0.72; 95% confidence interval [CI], 0.67-0.77; p < 0.001), length of stay (incidence rate ratio, 0.85; 95% CI, 0.84-0.87; p < 0.001), hospital-acquired infections (OR, 0.79; 95% CI, 0.73-0.86; p < 0.001), and acute myocardial infarction-stroke (OR, 0.69; 95% CI, 0.58-0.82; p < 0.001). All-cause emergency readmissions increased (OR, 1.06; 95% CI, 1.02-1.10; p = 0.001).

Conclusion: Implementation of a unique, jurisdiction-wide PBM program was associated with improved patient outcomes, reduced blood product utilization, and product-related cost savings.

Abstract
Iron deficiency is the most common nutrient deficiency in the world, affecting over 20% of premenopausal women worldwide. Oral iron supplementation is often the first-line treatment for the acute and chronic management of iron deficiency due to its ease and accessibility. However, there is no consensus on the optimal formulation or dosing strategy, or which patients should be preferentially treated with intravenous iron. Management of iron deficiency is complicated by the hepcidin-ferroportin iron regulatory pathway, which has evolved to prevent iron overload and thereby creates an inherent limit on gastrointestinal iron uptake and efficacy of oral iron. Unabsorbed iron propagates many of the side effects that complicate oral iron use including dyspepsia and constipation, all of which can thus be exacerbated by excessive oral iron doses. Daily low dose and every other day dosing protocols have attempted to bypass this physiologic bottleneck to allow for effective absorption and limit side effects; however, this approach has still resulted in low fractional iron absorption. In the following manuscript, we review the pathophysiology of iron absorption and current evidence for various preparations of oral iron. Lastly, we highlight opportunities for further study to advance the care of individuals affected by iron deficiency.

Abstract
Anaemia is common before major surgery and increases complications. A new guideline aims to help with early diagnosis of the type and cause of anaemia and initiate effective treatment. The guideline includes clear education for all staff and patients about the biology of iron homeostasis and patient blood management.

Abstract
Pre-operative anaemia is typically diagnosed with a haemoglobin concentration < 120 g.l-1 for women and < 130 g.l-1 for men on the basis of limited evidence. This retrospective cohort study stratified women undergoing elective, major abdominal surgery based on pre-operative haemoglobin concentration: anaemic (< 120 g.l-1 ); borderline anaemic (120-129 g.l-1 ); and non-anaemic (> 130 g.l-1 ). Data from 1554 women were analysed. Women with borderline anaemia had a greater incidence of postoperative complications (55 (16%) vs. 110 (11%); p = 0.026), longer duration of hospital stay (median (IQR [range]) 3 (1-6 [0-69]) days vs. 2 (1-5 [0-80]) days; p = 0.017) and fewer days alive and out of hospital at postoperative day 30 (median (IQR [range]) 27 (23-29 [0-30]) vs. 28 (25-29 [0-30]) days; p = 0.017) compared with non-anaemic women. However, after matched cohort analysis, these outcome differences no longer remained statistically significant. After multivariable adjustment for procedure, Charlson comorbidity index and patient age, a negative relationship between logarithmic pre-operative haemoglobin concentration and duration of stay was found (parameter estimate (standard error) -0.006 (0.003) vs. 0.003 (0.003) for a haemoglobin concentration < 130 g.l-1 vs. > 130 g.l-1 , respectively; p = 0.03); the difference in duration of stay was approximately 50% greater for women with a haemoglobin concentration of 120 g.l-1 compared with those with a haemoglobin concentration of 130 g.l-1 . Although the contribution of borderline anaemia to the incidence of postoperative complications is uncertain, the current diagnostic criteria should be re-assessed.

Abstract
Despite current recommendations on the management of pre-operative anaemia, there is no pragmatic guidance for the diagnosis and management of anaemia and iron deficiency in surgical patients. A number of experienced researchers and clinicians took part in an expert workshop and developed the following consensus statement. After presentation of our own research data and local policies and procedures, appropriate relevant literature was reviewed and discussed. We developed a series of best-practice and evidence-based statements to advise on patient care with respect to anaemia and iron deficiency in the peri-operative period. These statements include: a diagnostic approach for anaemia and iron deficiency in surgical patients; identification of patients appropriate for treatment; and advice on practical management and follow-up. We urge anaesthetists and peri-operative physicians to embrace these recommendations, and hospital administrators to enable implementation of these concepts by allocating adequate resources.

Abstract
The prevention and treatment of iron deficiency is a major public health goal. Challenges in the treatment of iron deficiency include finding and addressing the underlying cause and the selection of an iron replacement product which meets the needs of the patient. However, there are a number of non-evidence-based misconceptions regarding the diagnosis and management of iron deficiency, with or without anaemia, as well as inconsistency of terminology and lack of clear guidance on clinical pathways. In particular, the pathogenesis of iron deficiency is still frequently not addressed and iron not replaced, with indiscriminate red cell transfusion used as a default therapy. In our experience, this imprudent practice continues to be endorsed by non-evidence-based misconceptions. The intent of the authors is to provide a consensus that effectively challenges these misconceptions, and to highlight evidence-based alternatives for appropriate management (referred to as key points). We believe that this approach to the management of iron deficiency may be beneficial for both patients and healthcare systems. We stress that this paper solely presents the Authors' independent opinions. No pharmaceutical company funded or influenced the conception, development or writing of the manuscript.

Abstract
Background: Preoperative anaemia is common and occurs in 5% to 76% of patients preoperatively. It is associated with an increased risk of perioperative allogeneic blood transfusion, longer hospital stay, and increased morbidity and mortality. Iron deficiency is one of the most common causes of anaemia. Oral and intravenous iron therapy can be used to treat anaemia. Parenteral iron preparations have been shown to be more effective in conditions such as inflammatory bowel disease, chronic heart failure and postpartum haemorrhage due to rapid correction of iron stores. A limited number of studies has investigated iron therapy for the treatment of preoperative anaemia. The aim of this Cochrane Review is to summarise the evidence for iron supplementation, both enteral and parenteral, for the management of preoperative anaemia.

Objectives: To evaluate the effects of preoperative iron therapy (enteral or parenteral) in reducing the need for allogeneic blood transfusions in anaemic patients undergoing surgery.

Search methods: We ran the search on 30 July 2018. We searched the Cochrane Injuries Group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library), Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R), Embase Classic and Embase (Ovid), CINAHL Plus (EBSCO), PubMed, and clinical trials registries, and we screened reference lists. We ran a top-up search on 28 November 2019; one study is now awaiting classification.

Selection criteria: We included all randomised controlled trials (RCTs) that compared preoperative iron monotherapy to placebo, no treatment, standard care or another form of iron therapy for anaemic adults undergoing surgery. We defined anaemia as haemoglobin values less than 13 g/dL for males and 12 g/dL for non-pregnant females.

Data collection and analysis: Two review authors collected data and a third review author checked all collected data. Data were collected on the proportion of patients who receive a blood transfusion, the amount of blood transfused per patient (units), quality of life, ferritin levels and haemoglobin levels, measured as continuous variables at the following predetermined time points: pretreatment (baseline), preoperatively but postintervention, and postoperatively. We performed statistical analysis using the Cochrane software, Review Manager 5. We summarised outcome data in tables and forest plots. We used the GRADE approach to describe the quality of the body of evidence.

Main results: Six RCTs, with a total of 372 participants, evaluated preoperative iron therapy to correct anaemia before planned surgery. Four studies compared iron therapy (either oral (one study) or intravenous (three studies)) with no treatment, placebo or usual care, and two studies compared intravenous iron therapy with oral iron therapy. Iron therapy was delivered over a range of periods that varied from 48 hours to three weeks prior to surgery. The 372 participants in our analysis fall far short of the 819 required - as calculated by our information size calculation - to detect a 30% reduction in blood transfusions. Five trials, involving 310 people, reported the proportion of participants who received allogeneic blood transfusions. Meta-analysis of iron therapy versus placebo or standard care showed no difference in the proportion of participants who received a blood transfusion (risk ratio (RR) 1.21, 95% confidence interval (CI) 0.87 to 1.70; 4 studies, 200 participants; moderate-quality evidence). Only one study that compared oral versus intravenous iron therapy measured this outcome, and reported no difference in risk of transfusion between groups. There was no difference between the iron therapy and placebo/standard care groups for haemoglobin level preoperatively at the end of the intervention (mean difference (MD) 0.63 g/dL, 95% CI -0.07 to 1.34; 2 studies, 83 participants; low-quality evidence). However, intravenous iron therapy produced an increase in preoperative postintervention haemoglobin levels compared with oral iron (MD 1.23 g/dL, 95% CI 0.80 to 1.65; 2 studies, 172 participants; low-quality evidence). Ferritin levels were increased by intravenous iron, both when compared to standard care ((MD 149.00, 95% CI 25.84 to 272.16; 1 study, 63 participants; low-quality evidence) or to oral iron (MD 395.03 ng/mL, 95% CI 227.72 to 562.35; 2 studies, 151 participants; low-quality evidence). Not all studies measured quality of life, short-term mortality or postoperative morbidity. Some measured the outcomes, but did not report the data, and the studies which did report the data were underpowered. Therefore, uncertainty remains regarding these outcomes. The inclusion of new research in the future is very likely to change these results.

Authors' conclusions: The use of iron therapy for preoperative anaemia does not show a clinically significant reduction in the proportion of trial participants who received an allogeneic blood transfusion compared to no iron therapy. Results for intravenous iron are consistent with a greater increase in haemoglobin and ferritin when compared to oral iron, but do not provide reliable evidence. These conclusions are drawn from six studies, three of which included very small numbers of participants. Further, well-designed, adequately powered, RCTs are required to determine the true effectiveness of iron therapy for preoperative anaemia. Two studies are currently in progress, and will include 1500 randomised participants.

Abstract
Background: Preoperative anaemia affects a high proportion of patients undergoing major elective surgery and is associated with poor outcomes. We aimed to test the hypothesis that intravenous iron given to anaemic patients before major open elective abdominal surgery would correct anaemia, reduce the need for blood transfusions, and improve patient outcomes.

Methods: In a double-blind, parallel-group randomised trial, we recruited adult participants identified with anaemia at preoperative hospital visits before elective major open abdominal surgery at 46 UK tertiary care centres. Anaemia was defined as haemoglobin less than 130 g/L for men and 120 g/L for women. We randomly allocated participants (1:1) via a secure web-based service to receive intravenous iron or placebo 10-42 days before surgery. Intravenous iron was administered as a single 1000 mg dose of ferric carboxymaltose in 100 mL normal saline, and placebo was 100 mL normal saline, both given as an infusion over 15 min. Unblinded study personnel prepared and administered the study drug; participants and other clinical and research staff were blinded to treatment allocation. Coprimary endpoints were risk of the composite outcome of blood transfusion or death, and number of blood transfusions from randomisation to 30 days postoperatively. The primary analysis included all randomly assigned patients with data available for the primary endpoints; safety analysis included all randomly assigned patients according to the treatment received. This study is registered, ISRCTN67322816, and is closed to new participants.

Findings: Of 487 participants randomly assigned to placebo (n=243) or intravenous iron (n=244) between Jan 6, 2014, and Sept 28, 2018, complete data for the primary endpoints were available for 474 (97%) individuals. Death or blood transfusion occurred in 67 (28%) of the 237 patients in the placebo group and 69 (29%) of the 237 patients in the intravenous iron group (risk ratio 1·03, 95% CI 0·78-1·37; p=0·84). There were 111 blood transfusions in the placebo group and 105 in the intravenous iron group (rate ratio 0·98, 95% CI 0·68-1·43; p=0·93). There were no significant differences between the two groups for any of the prespecified safety endpoints.

Interpretation: Preoperative intravenous iron was not superior to placebo to reduce need for blood transfusion when administered to patients with anaemia 10-42 days before elective major abdominal surgery.

Abstract
Iron deficiency is a common cause of morbidity and can arise as a consequence or complication from many diseases. The use of intravenous iron has increased significantly in the last decade, but concerns remain about indications and administration. Modern intravenous iron preparations can facilitate rapid iron repletion in one or two doses, both for absolute iron deficiency and, in the presence of inflammation, functional iron deficiency, where oral iron therapy is ineffective or has not worked. A multidisciplinary team of experts experienced in iron deficiency undertook a consensus review to support healthcare professionals with practical advice on managing iron deficiency in gastrointestinal, renal and cardiac disease, as well as; pregnancy, heavy menstrual bleeding, and surgery. We explain how intravenous iron may work where oral iron has not. We provide context on how and when intravenous iron should be administered, and informed opinion on potential benefits balanced with potential side-effects. We propose how intravenous iron side-effects can be anticipated in terms of what they may be and when they may occur. The aim of this consensus is to provide a practical basis for educating and preparing staff and patients on when and how iron infusions can be administered safely and efficiently. Key messages Iron deficiency treatment selection is driven by several factors, including the presence of inflammation, the time available for iron replenishment, and the anticipated risk of side-effects or intolerance. Intravenous iron preparations are indicated for the treatment of iron deficiency when oral preparations are ineffective or cannot be used, and therefore have applicability in a wide range of clinical contexts, including chronic inflammatory conditions, perioperative settings, and disorders associated with chronic blood loss. Adverse events occurring with intravenous iron can be anticipated according to when they typically occur, which provides a basis for educating and preparing staff and patients on how iron infusions can be administered safely and efficiently.

Abstract
In the intravenous iron therapy to treat iron deficiency anaemia in patients undergoing major abdominal surgery (PREVENTT) trial, the use of intravenous iron did not reduce the need for blood transfusion or reduce patient complications or length of hospital stay. As part of the trial protocol, serum was collected at randomisation and on the day of surgery. These samples were analysed in a central laboratory for markers of iron deficiency. We performed a secondary analysis to explore the potential interactions between pre-operative markers of iron deficiency and intervention status on the trial outcome measures. Absolute iron deficiency was defined as ferritin <30 μg.l-1 ; functional iron deficiency as ferritin 30-100 μg.l-1 or transferrin saturation < 20%; and the remainder as non-iron deficient. Interactions were estimated using generalised linear models that included different subgroup indicators of baseline iron status. Co-primary endpoints were blood transfusion or death and number of blood transfusions, from randomisation to 30 days postoperatively. Secondary endpoints included peri-operative change in haemoglobin, postoperative complications and length of hospital stay. Most patients had iron deficiency (369/452 [82%]) at randomisation; one-third had absolute iron deficiency (144/452 [32%]) and half had functional iron deficiency (225/452 [50%]). The change in pre-operative haemoglobin with intravenous iron compared with placebo was greatest in patients with absolute iron deficiency, mean difference 8.9 g.l-1 , 95%CI 5.3-12.5; moderate in functional iron deficiency, mean difference 2.8 g.l-1 , 95%CI -0.1 to 5.7; and with little change seen in those patients who were non-iron deficient. Subgroup analyses did not suggest that intravenous iron compared with placebo reduced the likelihood of death or blood transfusion at 30 days differentially across subgroups according to baseline ferritin (p = 0.33 for interaction), transferrin saturation (p = 0.13) or in combination (p = 0.45), or for the number of blood transfusions (p = 0.06, 0.29, and 0.39, respectively). There was no beneficial effect of the use of intravenous iron compared with placebo, regardless of the metrics to diagnose iron deficiency, on postoperative complications or length of hospital stay.

Keywords: anaemia; iron; transfusion.

Abstract
By virtue of their religious principles, Jehovah's Witnesses (JWs) generally object to receiving blood products, raising numerous ethical, legal, and medical challenges for providers who care for these patients, especially in the emergent setting. In this review, we discuss several areas relevant to the care of JWs, including the current literature on "bloodless" medical care in the setting of perioperative and intraoperative management, acute blood loss, trauma, pregnancy, and malignancy. We have found that medical and administrative efforts in the form of bloodless medicine and surgery programs can be instrumental in helping to reduce risks of morbidity and mortality in these patients. Planning prior to an anticipated event associated with blood loss or anemia (such as elective surgery, pregnancy, and chemotherapy) is critical. Specifically, bloodless medicine programs should prioritize vigilant early screening and management of anemias, early establishment of patient wishes regarding transfusion, and the incorporation of those wishes into multidisciplinary medical and surgical care. Although there are now a variety of human-based and nonhuman-based products available as transfusion alternatives, the degree and quality of evidence to support their use varies significantly between products and is also largely dependent on the clinical setting.

Abstract
Background: Perioperative anemia has been associated with increased risk of red blood cell transfusion and increased morbidity and mortality after surgery. The optimal approach to the diagnosis and management of perioperative anemia is not fully established.

Objective: To develop consensus recommendations for anemia management in surgical patients.

Methods: An international expert panel reviewed the current evidence and developed recommendations using modified RAND Delphi methodology.

Results: The panel recommends that all patients except those undergoing minor procedures be screened for anemia before surgery. Appropriate therapy for anemia should be guided by an accurate diagnosis of the etiology. The need to proceed with surgery in some patients with anemia is expected to persist. However, early identification and effective treatment of anemia has the potential to reduce the risks associated with surgery and improve clinical outcomes. As with preoperative anemia, postoperative anemia should be treated in the perioperative period.

Abstract
Introduction: Erythropoiesis-stimulating agents (ESAs) are widely used in treating anemia associated with renal failure. They are also now used perioperatively to reduce the use of allogeneic blood transfusions (ABTs) in patients undergoing surgery with anticipated high blood loss. Although they can reduce the risks associated with ABT and improve quality of life, the use of ESAs is still associated with adverse effects.

Areas covered: A narrative review is provided on ESAs and a systematic review has been conducted to examine the current evidence for the efficacy and safety of perioperative ESAs use. A search of PubMed and Medline databases has been performed using a combination of search terms including erythropoietin, perioperative, surgical, safety and efficacy.

Expert opinion: Current evidence supports the use of perioperative ESAs to reduce the need for ABT. However, large studies assessing safety in anemic patients with chronic renal disease have found adverse effects including cardiovascular, stroke and thromboembolic events. However, whether these concerns can be conferred onto the surgical population remains to be seen as the perioperative dosing strategies have been more variable in timing, dose and duration in comparison with those used for chronic diseases. Future research needs to address the questions of optimal dosing strategies in order to maximize the positive effects and minimize adverse events.

Abstract
Our study investigated whether pre-operative screening and treatment for anaemia and suboptimal iron stores in a patient blood management clinic is cost effective. We used outcome data from a retrospective cohort study comparing colorectal surgery patients admitted pre- and post-implementation of a pre-operative screening programme. We applied propensity score weighting techniques with multivariable regression models to adjust for differences in baseline characteristics between groups. Episode-level hospitalisation costs were sourced from the health service clinical costing data system; the economic evaluation was conducted from a Western Australia Health System perspective. The primary outcome measure was the incremental cost per unit of red cell transfusion avoided. We compared 441 patients screened in the pre-operative anaemia programme with 239 patients not screened; of the patients screened, 180 (40.8%) received intravenous iron for anaemia and suboptimal iron stores. The estimated mean cost of screening and treating pre-operative anaemia was AU$332 (£183; US$231; €204) per screened patient. In the propensity score weighted analysis, screened patients were transfused 52% less red cell units when compared with those not screened (rate ratio = 0.48, 95%CI 0.36-0.63, p < 0.001). The mean difference in total screening, treatment and hospitalisation cost between groups was AU$3776 lower in the group screened (£2080; US$2629; €2325) (95%CI AU$1604-5947, p < 0.001). Screening elective patients pre-operatively for anaemia and suboptimal iron stores reduced the number of red cell units transfused. It also resulted in lower total costs than not screening patients, thus demonstrating cost effectiveness.

Abstract
Treatment with blood and 'its substitutes is a common practice in surgical patients who bleed perioperatively; also, nonsurgical patients with chronic disease receive blood/blood components. However, some patients refuse blood because of personal or religious beliefs, like in the case of Jehovah's Witnesses. Those patients may accept different artificial substitutes of blood components as well as some surgical techniques, that decrease the risk of bleeding or the volume of blood lost. It is extremely important to inform the patients about the risk of losing blood without its replacement and to get an informed consent, as well as to document which treatments and/or procedures the patient consents to and which they do not. Such patients must be correctly prepared for the operation with hematologic optimization. All drugs that influence hemostasis must be stopped preoperatively. There have been several interventions/methods of decreasing the need for transfusion developed. All surgeons and anesthesiologists must be familiar with indications and appropriate use of blood and blood components and their alternatives, but close liaison with hematology specialists and their local blood sciences laboratory is encouraged. Based on the latest guidelines, there are many options of preoperative preparations and treatment, very important for the surgical and anesthesiology team, described in the manuscript.

Abstract in English, French
Purpose: Iron supplementation has been evaluated in several randomized controlled trials (RCTs) for its potential to increase baseline hemoglobin and decrease red blood cell transfusion during cardiac surgery. This study's main objective was to evaluate the current evidence for iron administration in cardiac surgery patients.

Methods: We searched MEDLINE, EMBASE, CENTRAL, Web of Science databases, and Google Scholar from inception to 19 November 2020 for RCTs evaluating perioperative iron administration in adult patients undergoing cardiac surgery. The RCTs were assessed using a risk of bias assessment and the quality of evidence was assessed using the grading of recommendations, assessments, development, and evaluations.

Results: We reviewed 1,767 citations, and five studies (n = 554) met the inclusion criteria. The use of iron showed no statistical difference in incidence of transfusion (risk ratio, 0.86; 95% confidence interval, 0.65 to 1.13). Trial sequential analysis suggested an optimal information size of 1,132 participants, which the accrued information size did not reach.

Conclusion: The current literature does not support or refute the routine use of iron therapy in cardiac surgery patients.