Brenda J. Grossman

Red blood cell transfusion: A Clinical practice guideline from the AABB

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).

Clinical practice guidelines from the AABB: Red blood cell transfusion thresholds and storage

Importance More than 100 million units of blood are collected worldwide each year, yet the indication for red blood cell (RBC) transfusion and the optimal length of RBC storage prior to transfusion are uncertain. Objective To provide recommendations for the target hemoglobin level for RBC transfusion among hospitalized adult patients who are hemodynamically stable and the length of time RBCs should be stored prior to transfusion. Evidence Review Reference librarians conducted a literature search for randomized clinical trials (RCTs) evaluating hemoglobin thresholds for RBC transfusion (1950-May 2016) and RBC storage duration (1948-May 2016) without language restrictions. The results were summarized using the Grading of Recommendations Assessment, Development and Evaluation method. For RBC transfusion thresholds, 31 RCTs included 12 587 participants and compared restrictive thresholds (transfusion not indicated until the hemoglobin level is 7-8 g/dL) with liberal thresholds (transfusion not indicated until the hemoglobin level is 9-10 g/dL). The summary estimates across trials demonstrated that restrictive RBC transfusion thresholds were not associated with higher rates of adverse clinical outcomes, including 30-day mortality, myocardial infarction, cerebrovascular accident, rebleeding, pneumonia, or thromboembolism. For RBC storage duration, 13 RCTs included 5515 participants randomly allocated to receive fresher blood or standard-issue blood. These RCTs demonstrated that fresher blood did not improve clinical outcomes. Findings It is good practice to consider the hemoglobin level, the overall clinical context, patient preferences, and alternative therapies when making transfusion decisions regarding an individual patient. Recommendation 1: a restrictive RBC transfusion threshold in which the transfusion is not indicated until the hemoglobin level is 7 g/dL is recommended for hospitalized adult patients who are hemodynamically stable, including critically ill patients, rather than when the hemoglobin level is 10 g/dL (strong recommendation, moderate quality evidence). A restrictive RBC transfusion threshold of 8 g/dL is recommended for patients undergoing orthopedic surgery, cardiac surgery, and those with preexisting cardiovascular disease (strong recommendation, moderate quality evidence). The restrictive transfusion threshold of 7 g/dL is likely comparable with 8 g/dL, but RCT evidence is not available for all patient categories. These recommendations do not apply to patients with acute coronary syndrome, severe thrombocytopenia (patients treated for hematological or oncological reasons who are at risk of bleeding), and chronic transfusion-dependent anemia (not recommended due to insufficient evidence). Recommendation 2: patients, including neonates, should receive RBC units selected at any point within their licensed dating period (standard issue) rather than limiting patients to transfusion of only fresh (storage length: <10 days) RBC units (strong recommendation, moderate quality evidence). Conclusions and Relevance Research in RBC transfusion medicine has significantly advanced the science in recent years and provides high-quality evidence to inform guidelines. A restrictive transfusion threshold is safe in most clinical settings and the current blood banking practices of using standard-issue blood should be continued.

Platelet transfusion: a systematic review of the clinical evidence

Platelet (PLT) transfusion is indicated either prophylactically or therapeutically to reduce the risk of bleeding or to control active bleeding. Significant uncertainty exists regarding the appropriate use of PLT transfusion and the optimal threshold for transfusion in various settings. We formulated 12 key questions to assess the role of PLT transfusion.

A national survey of transfusion-related acute lung injury risk reduction policies for platelets and plasma in the United States

BACKGROUND: Little information exists on the specific transfusion‐related acute lung injury (TRALI) risk reduction practices used by multiple blood collecting institutions in the United States.

Antithrombin III: physiology, deficiency, and replacement therapy

FORMATION OF THE FIBRIN BLOOD CLOT OCCUrS as a result of a series of proteolytic reactions whereby proenzymes or zymogens are converted to proteolytic enzymes (proteinases), which ultimately leads to the generation of thrombin and the conversion of fibrinogen to fibrin. Antithrombin 111 (AT 111) is the major inhibitor of serine proteinases generated during the various phases of the coagulation process. Three coagulation proteinases, thrombin, factor Xa (FXa), and factor IXa (F IXa), are the main targets for the inhibitor. Factor XIa (FXIa) and factor XIIa (FXIIa) are to a lesser extent also inhibited by AT 111. Activated protein C and factor VIIa (FVIIa) are the only coagulation enzymes not affected by AT 111. In its function as an inhibitor of the proteinases generated during the coagulation process, AT I11 plays an important role in maintaining the hemostatic balance. This is illustrated by the fact that an inherited deficiency of AT 111 is associated with thromboembolism. The inhibitory effect of AT 111 is dramatically accelerated by heparin.

Increased risk of a positive test for antibody to hepatitis B core antigen (anti‐HBC) in autologous blood donors

ABSTRACT: Controversy exists about the suitability of blood from autologous donors for homologous use. We compared the infectious disease test results of 426 autologous donors, designated by donor history as suitable for homologous use, to those of 86,138 volunteer donations collected over the same 5 month period. Although donor characteristics differed, the relative risk of a positive test for anti‐HBc in the autologous group was 2.09. When 413 autologous donors were compared to 413 volunteer donors matched for age, sex, and zip code, the relative risk of a positive test for anti‐HBc in the autologous group was 3.2. If anti‐HBc is a marker for non‐A, non‐B hepatitis transmissibility, then our autologous group is not as safe as our volunteer donors. We recommend that autologous blood, even when designated by donor history and laboratory screening results as suitable for homologous transfusion, not be used for other than the intended autologous recipient.

Red Cell Transfusion Decreases Hemoglobin A1c in Patients with Diabetes

To the Editor: Hemoglobin A1c (Hb A1c)1 is a mainstay of diabetes diagnosis and management that allows clinicians to estimate the recent mean blood glucose concentration of a patient. Glycation of hemoglobin is an irreversible, nonenzymatic process that depends on the glucose concentration in red blood cells (RBCs), and Hb A1c represents the integrated glucose concentration in RBCs over their life span. RBC transfusion can complicate the interpretation of Hb A1c values in diabetic patients because it introduces hemoglobin molecules exposed to glucose concentrations that may have been different from the glucose concentrations in the diabetic transfusion recipient. The potential effect of transfusion on Hb A1c has been recognized for some time, but opinions on the direction of the effect are contradictory. Data from the older literature (1–3) suggest that the high concentration of glucose in RBC storage medium promotes glycation and causes Hb A1c values to increase over time, which would predict that Hb A1c might increase in transfused patients. This concept has been stated in a recent review article (4) and on consumer Web sites, such as Lab Tests Online (http://labtestsonline.org/understanding/analytes/a1c/test.html); however, a recent case in which a pathology resident was contacted to explain a patients Hb A1c value decreasing from 7.4% to 5.4% in 3 days after the patient …

Efficacy of extracorporeal photopheresis in clearance of antibodies to donor-specific and lung-specific antigens in lung transplant recipients

BACKGROUND Extracorporeal photopheresis (ECP) has been used to treat chronic rejection after lung transplantation (LTx). We investigated the effect of ECP on several immune parameters that have been associated with poor lung function, including donor-specific antibodies (DSA) to human leukocyte antigen (HLA), antibodies against the lung-associated self-antigens (SAg), Kα1-tubulin (Kα1T), collagen I and V, and circulating levels of pro-inflammatory and anti-inflammatory cytokines. METHODS Sera were collected from post-LTx patients diagnosed with bronchiolitis obliterans before and 6 months after initiation of ECP. DSA and cytokine levels were measured by Luminex (Invitrogen, Carlsbad, CA). Changes in lung function over the 6 months preceding and after the initiation of ECP were measured by retrospective analysis of spirometry performed at routine clinic visits. RESULTS ECP was associated with a significant decline in DSA levels as well as antibodies to lung-associated SAg. ECP also reduced circulating levels of pro-inflammatory cytokines and increased levels of anti-inflammatory cytokines. These immunologic changes were associated with a significant 63% reduction in the rate of decline in forced expiratory volume in 1 second over a 1-year period. Though statistically insignificant, a higher rate of clearance of antibodies to lung-associated SAg was strongly associated with better response to ECP. CONCLUSIONS ECP is associated with a reduction in the levels of circulating DSA, antibodies to lung-associated SAg (Kα1T, collagen I, and collagen V), and circulating levels of several pro-inflammatory cytokines. We propose that these changes contribute to the beneficial effect of ECP in reducing the decline in lung function.

TRANSFUSION PRACTICE: Liver donor's age and recipient's serum creatinine predict blood component use during liver transplantation

BACKGROUND: Excessive use of blood components during liver transplantation should be avoided because it has been associated with poor outcomes and it may stress blood bank resources.

Linear relationship between lymphocyte counts in peripheral blood and buffy coat collected during extracorporeal photopheresis.

Extracorporeal photopheresis (ECP) is commonly used to treat patients with graft‐versus‐host disease (GVHD) and lung transplant rejection (LTR) in our institution. The quantitative relationship between the number of white blood cells treated during ECP and the cell count in peripheral blood is unclear.