Abstract

BACKGROUND There are no overviews of systematic reviews investigating haemoglobin thresholds for transfusion. This is important as the literature on transfusion thresholds has grown considerably in recent years. Our aim was to synthesise evidence from systematic reviews and meta-analyses of the effects of restrictive and liberal transfusion strategies on mortality. METHODS This was a systematic review of systematic reviews (overview). We searched MEDLINE, Embase, Web of Science Core Collection, PubMed, Google Scholar, and the Joanna Briggs Institute EBP Database, from 2008 to 2018. We included systematic reviews and meta-analyses of randomised controlled trials comparing mortality in patients assigned to red cell transfusion strategies based on haemoglobin thresholds. Two independent reviewers extracted data and assessed methodological quality. We assessed the methodological quality of included reviews using AMSTAR 2 and the quality of evidence pooled using an algorithm to assign GRADE levels. RESULTS We included 19 systematic reviews reporting 33 meta-analyses of mortality outcomes from 53 unique randomised controlled trials. Of the 33 meta-analyses, one was graded as high quality, 15 were moderate, and 17 were low. Of the meta-analyses presenting high- to moderate-quality evidence, 12 (75.0%) reported no statistically significant difference in mortality between restrictive and liberal transfusion groups and four (25.0%) reported significantly lower mortality for patients assigned to a restrictive transfusion strategy. We found few systematic reviews addressed clinical differences between included studies: variation was observed in haemoglobin threshold concentrations, the absolute between group difference in haemoglobin threshold concentration, time to randomisation (resulting in transfusions administered prior to randomisation), and transfusion dosing regimens. CONCLUSIONS Meta-analyses graded as high to moderate quality indicate that in most patient populations no difference in mortality exists between patients assigned to a restrictive or liberal transfusion strategy. TRIAL REGISTRATION PROSPERO CRD42019120503.

Abstract

OBJECTIVES Assess support for the effectiveness of two separate practices, restrictive transfusion strategy and computerized physician order entry/clinical decision support (CPOE/CDS) tools, in decreasing RBC transfusions in adult surgical and nonsurgical patients. METHODS Following the Centers for Disease Control and Prevention Laboratory Medicine Best Practice (LMBP) Systematic Review (A-6) method, studies were assessed for quality and evidence of effectiveness in reducing the percentage of patients transfused and/or units of blood transfused. RESULTS Twenty-five studies on restrictive transfusion practice and seven studies on CPOE/CDS practice met LMBP inclusion criteria. The overall strength of the body of evidence of effectiveness for restrictive transfusion strategy and CPOE/CDS was rated as high. CONCLUSIONS Based on these procedures, adherence to an institutional restrictive transfusion strategy and use of CPOE/CDS tools for hemoglobin alerts or reminders of the institution's restrictive transfusion policies are effective in reducing RBC transfusion overuse.

Abstract

OBJECTIVES To evaluate the effectiveness of antifibrinolytics tranexamic acid (TA), epsilon-aminocaproic acid (EACA), and aprotinin to decrease overuse of red blood cell transfusions in adult surgical and non-surgical patients. METHODS This review followed the Centers for Disease Control and Prevention (CDC) Laboratory Medicine Best Practice (LMBP) Systematic Review (A-6) method. Eligible studies were assessed for evidence of effectiveness of TA or EACA in reducing the number of patients transfused or the number of whole blood transfusions. RESULTS Seventy-two articles met LMBP inclusion criteria. Fifty-six studies assessed Topical, Intra-articular Injection, or Intravenous TA, 4 studied EACA, and 12 studied the effectiveness of aprotinin. The overall strength of the body of evidence of effectiveness for each of these practices was rated as high. CONCLUSION LMBP recommends the use of topical, intra-articular injection, or intravenous tranexamic acid and the use of epsilon-aminocaproic acid for reducing overuse of red blood cell transfusion.

Abstract

Objectives: To evaluate the effectiveness of anemia management and audit with feedback practices in reducing overuse of RBC transfusion. Methods: This review follows the Centers for Disease Control and Prevention's Laboratory Medicine Best Practice Systematic Review (A-6) method. We searched the literature and solicited unpublished studies on practices to reduce overuse of RBC transfusions as measured by reductions in units transfused and proportion of patients transfused. Results: Thirteen studies on preoperative anemia management and three studies on audit feedback practices met inclusion criteria. Strength of evidence was high to moderate for reducing the number of units and proportion of patients transfused. Conclusions: Preoperative anemia management reduces the proportion of patients transfused and units of RBCs transfused. Audit with feedback across cases, physicians, and/or service areas, as part of a continuous quality improvement practice, reduces the proportion of patients and units of RBCs transfused.

Abstract

Description: Although approximately 85 million units of red blood cells (RBCs) are transfused annually worldwide, transfusion practices vary widely. The AABB (formerly, the American Association of Blood Banks) developed this guideline to provide clinical recommendations about hemoglobin concentration thresholds and other clinical variables that trigger RBC transfusions in hemodynamically stable adults and children. Methods: These guidelines are based on a systematic review of randomized clinical trials evaluating transfusion thresholds. We performed a literature search from 1950 to February 2011 with no language restrictions. We examined the proportion of patients who received any RBC transfusion and the number of RBC units transfused to describe the effect of restrictive transfusion strategies on RBC use. To determine the clinical consequences of restrictive transfusion strategies, we examined overall mortality, nonfatal myocardial infarction, cardiac events, pulmonary edema, stroke, thromboembolism, renal failure, infection, hemorrhage, mental confusion, functional recovery, and length of hospital stay. Recommendation 1: The AABB recommends adhering to a restrictive transfusion strategy (7 to 8 g/dL) in hospitalized, stable patients (Grade: strong recommendation; high-quality evidence). Recommendation 2: The AABB suggests adhering to a restrictive strategy in hospitalized patients with preexisting cardiovascular disease and considering transfusion for patients with symptoms or a hemoglobin level of 8 g/dL or less (Grade: weak recommendation; moderate-quality evidence). Recommendation 3: The AABB cannot recommend for or against a liberal or restrictive transfusion threshold for hospitalized, hemodynamically stable patients with the acute coronary syndrome (Grade: uncertain recommendation; very low-quality evidence). Recommendation 4: The AABB suggests that transfusion decisions be influenced by symptoms as well as hemoglobin concentration (Grade: weak recommendation; low-quality evidence). 2012 American College of Physicians.

Abstract

BACKGROUND There is little systematically derived evidence-based guidance to inform plasma transfusion decisions. To address this issue, the AABB commissioned the development of clinical practice guidelines to help direct appropriate transfusion of plasma. STUDY DESIGN AND METHODS A systematic review (SR) and meta-analysis of randomized and observational studies was performed to quantify known benefits and harms of plasma transfusion in common clinical scenarios (see accompanying article). A multidisciplinary guidelines panel then used the SR and the GRADE methodology to develop evidence-based plasma transfusion guidelines as well as identify areas for future investigation. RESULTS Based on evidence ranging primarily from moderate to very low in quality, the panel developed the following guidelines: 1) The panel suggested that plasma be transfused to patients requiring massive transfusion. However, 2) the panel could not recommend for or against transfusion of plasma at a plasma : red blood cell ratio of 1:3 or more during massive transfusion, 3) nor could the panel recommend for or against transfusion of plasma to patients undergoing surgery in the absence of massive transfusion. 4) The panel suggested that plasma be transfused in patients with warfarin therapy-related intracranial hemorrhage, 5) but could not recommend for or against transfusion of plasma to reverse warfarin anticoagulation in patients without intracranial hemorrhage. 6) The panel suggested against plasma transfusion for other selected groups of patients. CONCLUSION We have systematically developed evidence-based guidance to inform plasma transfusion decisions in common clinical scenarios. Data from additional randomized studies will be required to establish more comprehensive and definitive guidelines for plasma transfusion.

Abstract

Untreated preoperative anemia and acute perioperative blood loss may add to surgical risk. To understand the prevalence of anemia in surgical patients (with a primary focus on preoperative anemia), and the impact that preexisting anemia has on transfusion rates as well as on clinical and functional outcomes, a systematic review was performed of articles published between January 1966 and February 2003. The estimates of anemia prevalence in the literature ranged widely, from 5% in geriatric women with hip fracture to 75.8% in patients with Dukes stage D colon cancer. Diagnosis of anemia was most strongly associated with an increased risk of receiving an allogeneic transfusion. In general, patients who donated autologous blood preoperatively received less allogeneic blood than those who did not donate. There was some suggestion that lower hemoglobin levels are associated with decreased survival rates, although this was not found universally. Too few studies were found that evaluated the impact of anemia on other outcomes, such as functional status and costs and resource utilization, to draw reliable conclusions. Several other factors also limited the interpretation of the data, including the lack of a uniform definition for anemia and a dearth of studies expressly designed to quantify the prevalence and impact of anemia. Establishing a uniform definition and specifically evaluating the effect of anemia on outcomes are important considerations for future study.