IN THE NAME OF GODIn the name

of God

Transfusion

Presented by: a.pourhosseini

Background

Human blood replacement therapy was accepted in the late nineteenth century. This was followed by the introduction of blood grouping by Dr. Karl Landsteiner, who identified the major A, B, and O groups in 1900. In 1939 Dr. Philip Levine and Dr. Rufus Stetson followed with the concept of Rh grouping. These breakthroughs established the foundation from which the field of transfusion medicine has grown. Whole blood was considered the standard in transfusion until the late 1970s, when goal-directed component therapy began to take prominence. This change in practice was made possible by the development of improved collection strategies, testing for infection, and advances in preservative solutions and storage.

Typing and Cross-Matching

Serologic compatibility for A, B, O, and Rh groups is established routinely. Cross-matching between donors' red blood cells and recipients' sera (the major cross-match) is performed. Rh-negative recipients should receive transfusions only of Rh-negative blood. However, this group represents only 15% of the population. Therefore, the administration of Rh-positive blood is acceptable if Rh-negative blood is not available. However, Rh-positive blood should not be transfused to Rh-negative females who are of childbearing age.

Cont…

In emergency situations, type O-negative blood may be transfused to all recipients. O-negative and type-specific red blood cells are equally safe for emergency transfusion. Problems are associated with the administration of 4 or more units of O-negative blood, because there is a significant increase in the risk of hemolysis. In patients with clinically significant levels of cold agglutinins, blood should be administered through a blood warmer. If these antibodies are present in high titer, hypothermia is contraindicated.

Cont…

In patients who have been transfused multiple times and who have developed alloantibodies or who have autoimmune hemolytic anemia with pan–red blood cell antibodies, typing and cross-matching is often difficult, and sufficient time should be allotted preoperatively to accumulate blood that might be required during the operation. Cross-matching should always be performed before the administration of dextran, because it interferes with the typing procedure.

Cont…

The use of autologous transfusion is growing. Up to 5 units can be collected for subsequent use during elective procedures. Patients can donate blood if their hemoglobin concentration exceeds 11 g/dL or if the hematocrit is >34%. The first procurement is performed 40 days before the planned operation and the last one is performed 3 days before the operation. Donations can be scheduled at intervals of 3 to 4 days. Administration of recombinant human erythropoietin accelerates generation of red blood cells and allows for more frequent harvesting of blood.

Banked Whole Blood

Banked whole blood, once the gold standard, is rarely available. The shelf life is now around 6 weeks. At least 70% of the transfused erythrocytes remain in the circulation for 24 hours after transfusion and are viable. The age of red cells may play a significant role in the inflammatory response and incidence of multiple organ failure. The changes in the red blood cells that occur during storage include reduction of intracellular ADP and 2,3-diphosphoglycerate, which alters the oxygen dissociation curve of hemoglobin and results in a decrease in oxygen transport. Although all clotting factors are relatively stable in banked blood except for factors V and VIII, banked blood progressively becomes acidotic with elevated levels of lactate, potassium, and ammonia. The hemolysis that occurs during storage is insignificant.

Fresh Whole Blood

Fresh whole blood refers to blood that is administered within 24 hours of its donation. Advances in testing for infectious disease now make fresh whole blood another option. Recent evidence has shown that the use of fresh whole blood may improve outcomes in patients with trauma-associated coagulopathy in the combat situation, and a civilian study will soon be under way. An advantage to the use of fresh whole blood is that it provides greater coagulation activity than equal units of component

Packed Red Blood Cells and Frozen Red Blood Cells

Packed red blood cells are the product of choice for most clinical situations. Concentrated suspensions of red blood cells can be prepared by removing most of the supernatant plasma after centrifugation. This preparation reduces, but does not eliminate, reaction caused by plasma components. It also reduces the amount of sodium, potassium, lactic acid, and citrate administered. Frozen red blood cells are not available for use in emergencies. They are used for patients who are known to have been previously sensitized. By freezing red blood cells viability is theoretically improved, and the ATP and 2,3-diphosphoglycerate concentrations are maintained. Little clinical outcome data are available to substantiate these findings.

Leukocyte-Reduced and Leukocyte-Reduced/Washed Red Blood Cells

Leukocyte-reduced and leukocyte-reduced/washed red blood cell products are prepared by filtration that removes approximately 99.9% of the white blood cells and most of the platelets (leukocyte-reduced red blood cells), and if necessary, by additional saline washing (leukocyte-reduced/washed red blood cells). Leukocyte reduction prevents almost all febrile, nonhemolytic transfusion reactions (fever and/or rigors), alloimmunization to HLA class I antigens, and platelet transfusion refractoriness as well as cytomegalovirus transmission. In most western nations, it is the standard red blood cell transfusion product.

Cont…

Opponents of universal leukoreduction believe that the additional costs associated with this process are not justified because they are of the opinion that transfused allogenic white blood cells have no significant immunomodulatory effects. Supporters of universal leukocyte reduction argue that allogenic transfusion of white cells predisposes to postoperative bacterial infection and multiorgan failure. Reviews of randomized trials and meta-analysis have not provided convincing evidence either way, although a large Canadian retrospective study suggests a decrease in mortality and infections when leukocyte-reduced red blood cells are used.

Platelet Concentrates

The indications for platelet transfusion include thrombocytopenia caused by massive blood loss and replacement with platelet-poor products, thrombocytopenia caused by inadequate platelet production, and qualitative platelet disorders. The shelf life of platelets is 120 hours from time of donation. One unit of platelet concentrate has a volume of approximately 50 mL. Platelet preparations are capable of transmitting infectious diseases and can provoke allergic reactions similar to those caused by blood transfusion.

Cont…

Therapeutic levels of platelets reached after therapy are in the range of 50,000 to 100,000/μL. However, there is a growing body of information suggesting that platelet transfusion thresholds can safely be lowered in patients who have no signs of hemostatic deficiency and who have no history of poor tolerance to low platelet counts. Prevention of HLA alloimmunization can be achieved by leukocyte reduction through filtration. In rare cases, such as in patients who have become alloimmunized through previous transfusion or patients who are refractory from sensitization through prior pregnancies, HLA-matched platelets can be used.

Fresh-Frozen Plasma

Fresh-frozen plasma (FFP) prepared from freshly donated blood is the usual source of the vitamin K–dependent factors and is the only source of factor V. However, FFP carries infectious risks similar to those of other component therapies. FFP has come to the forefront with the inception of damage control resuscitation in patients with trauma-associated coagulopathy. In an effort to increase the shelf life and avoid the need for refrigeration, lyophilized plasma is being tested. Preliminary animal studies suggest that this process preserves the beneficial effects of FFP.

Concentrates and Recombinant DNA Technology

Technologic advancements have made the majority of clotting factors and albumin readily available as concentrates. These products are readily obtainable and carry no inherent infectious risks as do other component therapies.

Human Polymerized Hemoglobin (Polyheme)

Human polymerized hemoglobin (PolyHeme) is a universally compatible, immediately available, disease-free, oxygen-carrying resuscitative fluid that has been successfully used in massively bleeding patients when red blood cells were not transfused. Advantages of an artificial oxygen carrier include the absence of blood-type antigens (no cross-match needed) and viral infections and long-term stability, which allows prolonged periods of storage. Disadvantages include shorter half-life in the bloodstream and the potential to increase cardiovascular complications. This product has not yet been approved for use in patients.

Indications for Replacement of Blood and Its Elements

1) Improvement in Oxygen-Carrying Capacity

2)Treatment of Anemia: Transfusion Trigger

3)Volume Replacement

A healthy adult can lose up to 15% of total blood volume (class I hemorrhage or up to 750 mL) with only minor effects on the circulation. Loss of 15 to 30% of blood volume (class II hemorrhage or 750 to 1500 mL) is associated with tachycardia and decreased pulse pressure but, importantly, a normal blood pressure. Loss of 30 to 40% (class III hemorrhage or 1500 to 2000 mL) results in tachycardia, tachypnea, hypotension, oliguria, and changes in mental status. Class IV hemorrhage is loss of >40% of blood volume and is considered life-threatening.

Damage Control Resuscitation

Current resuscitation algorithms are based on the sequence of crystalloid followed by red blood cells and then plasma and platelet transfusions and have been in widespread use since the 1970s. Recently, the damage control resuscitation (DCR) strategy, aimed at halting and/or preventing rather than treating the lethal triad of coagulopathy, acidosis, and hypothermia, has challenged traditional thinking on early resuscitation strategies.

Rationale

In civilian trauma systems nearly half of all deaths occur before a patient reaches the hospital, and few of these deaths are preventable. Those patients who survive until arrival at an emergency center have a high incidence of truncal hemorrhage, and deaths in this group of patients may be potentially preventable. Truncal hemorrhage patients in shock often present with the early coagulopathy of trauma in the emergency department and are at significant risk of dying.

Many of these patients receive a massive transfusion, generally defined as the administration of 10 or more units of packed red blood cells within 24 hours of admission. Although 25% of all trauma patients admitted receive a unit of blood early after admission, only a small percentage of patients receive a massive transfusion. In the military setting, however, the percentage of patients receiving a massive transfusion almost doubles.

Complications of Transfusion

Nonhemolytic Reactions Allergic Reactions Respiratory Complications Hemolytic Reactions Transmission of Disease

Transmission of Disease

Malaria,Chagas' disease, brucellosis, and, very rarely, syphilis,CMV

hepatitis C virus and HIV-1 Hepatitis A virus other pathogens, such as West Nile virus Prion disorders (e.g., Creutzfeldt-Jakob

disease)

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