Chpt 28- Hematologic function

Blood

Erythrocytes (red blood cells [RBCs], red cells), leukocytes (white blood cells [WBCs]), and thrombocytes (platelets) Cellular component makes up 40-50% of blood volume Most RBC have short lifespan, body continuous supply- hematopoiesis- bone marrow Under normal conditions, the adult bone marrow produces about 175 billion erythrocytes, 70 billion neutrophils (a mature type of WBC), and 175 billion platelets each day. When the body needs more blood cells, as in infection (when neutrophils are needed to fight the invading pathogen) or in bleeding (when more RBCs are required), the marrow increases its production of the cells required. Thus, under normal conditions, the marrow responds to increased demand and releases adequate numbers of cells into the circulation. Blood makes up approximately 7% to 9% of the normal body weight and amounts to 5 to 6 L of volume for men and 4 to 5 L of volume for women Circulating through the vascular system and serving as a link between body organs, blood carries oxygen absorbed from the lungs and nutrients absorbed from the gastrointestinal (GI) tract to the body cells for cellular metabolism. Blood also carries hormones, antibodies, and other substances to their sites of action or use. In addition, blood carries waste products produced by cellular metabolism to the lungs, skin, liver, and kidneys, where they are transformed and eliminated from the body. Body dissolves clot with fibrinolysis or hemostasis

Lymphocytes

Immature lymphocytes are produced in the marrow from the lymphoid stem cells. A second major source of production for lymphocytes is the thymus. Cells derived from the thymus are known as T lymphocytes (or T cells); those derived from the marrow can also be T cells but are more commonly B lymphocytes (or B cells). Lymphocytes complete their differentiation and maturation primarily in the lymph nodes and in the lymphoid tissue of the intestine and spleen after exposure to a specific antigen. Mature lymphocytes are the principal cells of the immune system, producing antibodies and identifying other cells and organisms as "foreign." Natural killer (NK) cells serve an important role in the body's immune defense system. Like other lymphocytes, NK cells accumulate in the lymphoid tissues (especially spleen, lymph nodes, and tonsils), where they mature. When activated, they serve as potent killers of virus-infected and cancer cells. They also secrete cytokines to mobilize the T and B cells into action.

Type of Apheresis

Plateletpheresis Remove platelets Extreme thrombocytosis, essential thrombocythemia (temporary measure); single-donor platelet transfusion Leukapheresis Remove WBCs (can be specific to neutrophils or lymphocytes) Extreme leukocytosis (e.g., AML, CML) (very temporary measure); harvest WBCs for transfusion Erythrocytapheresis (RBC exchange) Remove RBCs RBC dyscrasias (e.g., sickle cell disease); RBCs replaced via transfusion Plasmapheresis (plasma exchange) Remove plasma proteins Hyperviscosity syndromes; treatment for some renal and neurologic diseases (e.g., Goodpasture syndrome, TTP, Guillain-Barré, myasthenia gravis) Stem cell harvest Remove circulating stem cells Transplantation (donor harvest or autologous)

Function of leukocytes

Protect the body from invasion by bacteria and other foreign entities. The major function of neutrophils is phagocytosis. Neutrophils arrive at a given site within 1 hour after the onset of an inflammatory reaction and initiate phagocytosis, but they are short-lived. An influx of monocytes follows; these cells continue their phagocytic activities for long periods as macrophages. This process constitutes a second line of defense for the body against inflammation and infection. Although neutrophils can often work adequately against bacteria without the help of macrophages, macrophages are particularly effective against fungi and viruses. Macrophages also digest senescent (aging or aged) blood cells, primarily within the spleen. The primary function of lymphocytes is to attack foreign material. One group of lymphocytes (T lymphocytes) kills foreign cells directly or releases lymphokines, substances that enhance the activity of phagocytic cells. T lymphocytes are responsible for delayed allergic reactions, rejection of foreign tissue (e.g., transplanted organs), and destruction of tumor cells. This process is known as cellular immunity. The other group of lymphocytes (B lymphocytes) is capable of differentiating into plasma cells. Plasma cells, in turn, produce antibodies called immunoglobulins (Igs), which are protein molecules that destroy foreign material by several mechanisms. This process is known as humoral immunity. Eosinophils and basophils function in hypersensitivity reactions. Eosinophils are important in the phagocytosis of parasites. The increase in eosinophil levels in allergic states indicates that these cells are involved in the hypersensitivity reaction; they neutralize histamine. Basophils produce and store histamine as well as other substances involved in hypersensitivity reactions. The release of these substances provokes allergic reactions

Allergic reaction

Some patients develop urticaria (hives) or generalized itching during a transfusion; the cause is thought to be a sensitivity reaction to a plasma protein within the blood component being transfused. Symptoms of an allergic reaction are urticaria, itching, and flushing. The reactions are usually mild and respond to antihistamines. If the symptoms resolve after administration of an antihistamine (e.g., diphenhydramine), the transfusion may be resumed. Rarely, the allergic reaction is severe, with bronchospasm, laryngeal edema, and shock. These reactions are managed with epinephrine, corticosteroids, and vasopressor support, if necessary. Giving the patient antihistamines or corticosteroids before the transfusion may prevent future reactions. For severe reactions, future blood components are washed to remove any remaining plasma proteins. Leukocyte filters are not useful to prevent such reactions, because the offending plasma proteins can pass through the filter.

Pharmacologic alternatives

Stimulate the production of one or more types of blood cells by the marrow are commonly use. Manufacturing artificial blood is problematic, given the myriad functions of blood components. Currently, there are two types of products in development: hemoglobin-based oxygen carriers and perfluorocarbons (which can dissolve gases and thus carry oxygen indirectly); none are approved for use in humans, to date Growth Factors Recombinant technology has provided a means to produce hematopoietic growth factors necessary for the production of blood cells within the bone marrow. By increasing the body's production of blood cells, transfusions and complications resulting from diminished blood cells (e.g., infection from neutropenia) may be avoided. However, the successful use of growth factors requires functional bone marrow. Moreover, the safety of these products has been questioned, and the U.S. Food and Drug Administration is limiting their use in some patient populations.

Nursing management of Transfusion

Stop the transfusion. Maintain the IV line with normal saline solution through new IV tubing, given at a slow rate. Assess the patient carefully. Compare the vital signs with baseline, including oxygen saturation. Assess the patient's respiratory status carefully. Note the presence of adventitious breath sounds; the use of accessory muscles; the extent of dyspnea; and changes in mental status, including anxiety and confusion. Note any chills, diaphoresis, jugular vein distention, and reports of back pain or urticaria. Notify the primary provider of the assessment findings and implement any treatments prescribed. Continue to monitor the patient's vital signs and respiratory, cardiovascular, and renal status. Notify the blood bank that a suspected transfusion reaction has occurred. Send the blood container and tubing to the blood bank for repeat typing and culture. The patient's identity and blood component identifying tags and numbers are verified. If a hemolytic transfusion reaction or bacterial infection is suspected, the nurse does the following: Obtains appropriate blood specimens from the patient. Collects a urine sample as soon as possible to detect hemoglobin in the urine. Documents the reaction according to the institution's policy.

Blood Donation

The intent of the interview is to assess the general health status of the donor and to identify risk factors that might harm a recipient of the donor's blood. There is no upper age limit to donation. The American Red Cross requires that donors be in good health and meet specific eligibility criteria related to medications and vaccinations, medical conditions and treatments, travel outside the United States, lifestyle and life events Body weight should be at least 50 kg (110 lb) for a standard 450-mL donation. Donors must wait at least 8 weeks between whole blood (standard) donations. People younger than 17 years require parental consent in some states. The oral temperature should not exceed 37.5°C (99.6°F). The systolic arterial blood pressure should be 80 to 180 mm Hg, and the diastolic pressure should be 50 to 100 mm Hg. The hemoglobin level should be at least 12.5 g/dL. The destinations of people who traveled outside the United States and Canada within the past 3 years are reviewed; a waiting period maybe required before a donation is accepted. Prospective donors who received a blood transfusion must wait 12 months before a donation is accepted. Men who have sexual relations with men must wait 3 months from their last sexual encounter before a donation is accepted.

Assessment

A careful health history and physical assessment can provide important information related to a patient's known or potential hematologic diagnosis. Because many hematologic disorders are more prevalent in certain ethnic groups, assessments of ethnicity and family history are useful. Similarly, obtaining a nutritional history and assessing the use of prescription and over-the-counter medications, as well as herbal supplements, are important to note, because several conditions can result from nutritional deficiencies, or from the use of certain herbs or medications. Careful attention to the onset of a symptom or finding (e.g., rapid vs. gradual; persistent vs. intermittent), its severity, and any contributing factors can further differentiate potential causes. Of equal importance is assessing the impact of these findings on the patient's functional ability, manifestations of distress, and coping mechanisms. Collect family Hx on maternal and paternal from 3 generations Assess family hx with blood disorders or abnormal bleeding

Transfusion procedures

A febrile nonhemolytic reaction is caused by antibodies to donor leukocytes that remain in the unit of blood or blood component; it is the most common type of transfusion reaction. It occurs more frequently in patients who have had previous transfusions (exposure to multiple antigens from previous blood products) and in Rh-negative women who have borne Rh-positive children (exposure to an Rh-positive fetus raises antibody levels in the untreated mother). The diagnosis of a febrile nonhemolytic reaction is made by excluding other potential causes, such as a hemolytic reaction or bacterial contamination of the blood product. The signs and symptoms of a febrile nonhemolytic transfusion reaction are chills (minimal to severe) followed by fever (more than 1°C elevation). The fever typically begins within 2 hours after the transfusion has begun. Although the reaction is not life threatening, the fever, and particularly the chills and muscle stiffness, can be frightening to the patient. This reaction can be diminished, even prevented, by further depleting the blood component of donor leukocytes; this is accomplished by a leukocyte reduction filter. Antipyretic agents can be given to prevent fever; however, routine premedication is not advised because it can mask the beginning of a more serious transfusion reaction.

Autologous Donation

A patient's own blood may be collected for future transfusion; this method is useful for many elective surgeries where the potential need for transfusion is high (e.g., orthopedic surgery). Preoperative donations are ideally collected 4 to 6 weeks before surgery. Iron supplements are prescribed during this period to prevent depletion of iron stores. Typically, 1 unit of blood is drawn each week; the number of units obtained varies with the type of surgical procedure to be performed (i.e., the amount of blood anticipated to be transfused). Phlebotomies are not performed within 72 hours of surgery. Individual blood components can also be collected. The primary advantage of autologous transfusions is the prevention of viral infections from another person's blood. Other advantages include safe transfusion for patients with a history of transfusion reactions, prevention of alloimmunization, and avoidance of complications in patients with alloantibodies. It is the policy of the American Red Cross that autologous blood is transfused only to the donor. If the blood is not required, it is discarded. The blood is never returned to the general donor supply of blood products to be used by another person Needless autologous donation (i.e., performed when the likelihood of transfusion is small) is discouraged because it is expensive, takes time, and uses resources inappropriately. Moreover, in an emergency situation, the autologous units available may be inadequate, and the patient may still require additional units from the general donor supply. Furthermore, although autologous transfusion can eliminate the risk of viral contamination, the risk of bacterial contamination is the same as that in transfusion from random donors Contraindications to donation of blood for autologous transfusion are acute infection, severely debilitating chronic disease, hemoglobin level less than 11 g/dL, unstable angina, and acute cardiovascular or cerebrovascular disease. A history of poorly controlled epilepsy may be considered a contraindication in some centers.

Blood component

A single unit of whole blood contains 450 mL of blood and 50 mL of an anticoagulant, which can be processed and dispensed for administration. However, it is more appropriate, economical, and practical to separate that unit of whole blood into its primary components: erythrocytes, platelets, and plasma (leukocytes are rarely used; see later discussion). Each component must be processed and stored differently to maximize the longevity of the viable cells and factors within it; thus, each individual blood component has a different storage life. Because the plasma is removed, a unit of packed red blood cells (PRBCs) is very concentrated (hematocrit approximately 70%). PRBCs are stored at 4°C (39.2°F). With special preservatives, they can be stored safely for up to 42 days before they must be discarded In contrast, platelets must be stored at room temperature because they cannot withstand cold temperatures, and they last for only 5 days before they must be discarded. To prevent clumping, platelets are gently agitated while stored. Plasma is immediately frozen to maintain the activity of the clotting factors within; it lasts for 1 year if it remains frozen. Alternatively, plasma can be further pooled and processed into blood derivatives, such as albumin, immune globulin, factor VIII, and factor IX

Transfusion

Administration of blood and blood components requires knowledge of correct administration techniques and possible complications. It is very important to be familiar with the agency's policies and procedures for transfusion therapy. Most blood transfusions are performed in the acute care setting, and sometimes must be done emergently. Patients with long-term transfusion requirements (i.e., patients who require transfusions on an ongoing, periodic basis) often can receive transfusions in other settings. Freestanding infusion centers, ambulatory care clinics, physicians' offices, and even patients' homes may be appropriate settings for transfusion. Typically, patients who need long-term transfusions but are otherwise stable physically are appropriate candidates for outpatient therapy. Verification and administration of the blood product are performed as in a hospital setting. Although most blood products can be transfused in the outpatient setting, the home is typically limited to transfusions of PRBCs and factor components (e.g., factor VIII for patients with hemophilia).

Plasma and protein

After cellular elements are removed from blood, the remaining liquid portion is called plasma. More than 90% of plasma is water. The remainder consists primarily of plasma proteins; clotting factors (particularly fibrinogen); and small amounts of other substances, such as nutrients, enzymes, waste products, and gases. If plasma is allowed to clot, the remaining fluid is called serum. Serum has essentially the same composition as plasma, except that fibrinogen and several clotting factors have been removed during the clotting process. Plasma proteins consist primarily of albumin and globulins. The globulins can be separated into three main fractions (alpha, beta, and gamma), each of which consists of distinct proteins that have different functions. Important proteins in the alpha and beta fractions are the transport globulins and the clotting factors that are made in the liver. The transport globulins carry various substances in bound form in the circulation. For example, thyroid-binding globulin carries thyroxin, and transferrin carries iron. The clotting factors, including fibrinogen, remain in an inactive form in the blood plasma until activated by the clotting cascade. The gamma-globulin fraction refers to the Igs, or antibodies. These proteins are produced by well-differentiated B lymphocytes and plasma cells. The actual fractionation of the globulins can be seen on a specific laboratory test (serum protein electrophoresis). Albumin is particularly important for the maintenance of fluid balance within the vascular system. Capillary walls are impermeable to albumin, so its presence in the plasma creates an osmotic force that keeps fluid within the vascular space. Albumin, which is produced by the liver, has the capacity to bind to several substances that are transported in plasma (e.g., certain medications, bilirubin, and some hormones). People with impaired hepatic function may have low concentrations of albumin, with a resultant decrease in osmotic pressure and the development of edema.

Directed Donation

At times, friends and family of a patient wish to donate blood for that person. These blood donations are referred to as directed donations. These donations are not any safer than those provided by random donors, because directed donors may not be as willing to identify themselves as having a history of any of the risk factors that disqualify a person from donating blood. Therefore, many blood centers no longer accept directed donations.

Hematologic disorders

Autosomal Dominant: •Factor V Leiden •Familial hypercholesterolemia •Hereditary angioedema •Hereditary spherocytosis •von Willebrand disease Autosomal Recessive: •Hemochromatosis •Sickle cell disease •Thalassemia X-Linked: •Hemophilia Assess for specific symptoms of hematologic diseases: •Extreme fatigue (the most common symptom of hematologic disorders) •Delayed clotting of blood •Easy or deep bruising •Abnormal bleeding (e.g., frequent nosebleeds) •Abdominal pain (hemochromatosis) or joint pain (sickle cell disease) •Review blood cell counts for abnormalities. •Assess for presence of illness despite low risk for the illness (e.g., a young adult with a blood clot)

Preprocedure

Confirm that the transfusion has been prescribed. 2.Check that patient's blood has been typed and cross-matched. 3.Verify that patient has signed a written consent form per institution or agency policy and agrees to procedure. 4.Explain procedure to patient. Educate patient about signs and symptoms of transfusion reaction (itching, hives, swelling, shortness of breath, fever, chills). 5.Take patient's temperature, pulse, respiration, blood pressure, and assess fluid volume status (e.g., auscultate lungs, assess for jugular venous distention) to serve as a baseline for comparison during transfusion. 6.Note if signs of increased fluid overload present Use hand hygiene and wear gloves in accordance with standard precautions. 8.Use appropriately sized intravenous cannula for insertion in a peripheral vein.a Use special tubing that contains a blood filter to screen out fibrin clots and other particulate matter. Do not vent blood container.

Transfusion of Platelets or Fresh Frozen Plasma

Confirm that the transfusion has been prescribed. 2.Verify that patient has signed a written consent form per institution or agency policy and agrees to procedure. 3.Explain procedure to patient. Educate patient about signs and symptoms of transfusion reaction (itching, hives, swelling, shortness of breath, fever, chills). 4.Take patient's temperature, pulse, respiration, blood pressure, and assess fluid status, and auscultate breath sounds to establish a baseline for comparison during transfusion. 5.Note if signs of increased fluid overload present Use hand hygiene and wear gloves in accordance with standard precautions. 7.Use a 22-gauge or larger needle or catheter for placement in a large vein, if possible. Use appropriate tubing per institution policy (platelets often require different tubing from that used for other blood products).

Delayed Hemolytic reaction

Delayed hemolytic reactions usually occur within 14 days after transfusion, when the level of antibody has been increased to the extent that a reaction can occur. The hemolysis of the erythrocytes is extravascular via the RES and occurs gradually. Signs and symptoms of a delayed hemolytic reaction are fever, anemia, increased bilirubin level, decreased or absent haptoglobin, and possibly jaundice. Rarely, there is hemoglobinuria. Generally, these reactions are not dangerous, but it is important to recognize them because subsequent transfusions with blood products containing these antibodies may cause a more severe hemolytic reaction. However, recognition is also difficult because the patient may not be in a health care setting to be tested for this reaction, and even if the patient is hospitalized, the reaction may be too mild to be recognized clinically. Because the amount of antibody present can be too low to detect, it is difficult to prevent delayed hemolytic reactions. Fortunately, the reaction is usually mild and requires no intervention

Bone marrow aspiration and biopsy

Document infection or tumor within marrow Determine blood formation, quality, and quantity In adults, bone marrow is usually aspirated from the iliac crest and occasionally from the sternum. The bone marrow aspirate provides a sample of cells from the more fluid part of the bone marrow and may not be adequate for evaluating certain conditions, such as anemia. When more information is required, a bone marrow biopsy is performed, which examines a solid part of the bone marrow. Biopsy samples are taken from the posterior iliac crest; although occasionally, an anterior approach is required. A marrow biopsy shows the architecture of the bone marrow as well as its degree of cellularity. Patient preparation includes a careful explanation of the procedure, which may be done at the patient's bedside (for a patient who is hospitalized) or in the outpatient setting. Some patients may be anxious, thus an anxiolytic agent may be prescribed. It is essential the physician or nurse explain the procedure, including risks, benefits and alternatives, and describe sensations the patient may experience. A signed informed consent is required for a bone marrow aspiration and Aseptic technique, brief and sharp pain upon aspiration Bone marrow exam-The bone marrow aspirate is used to determine types and numbers of cells present in the bone marrow. The bone marrow biopsy consists of an actual tissue sample used to study the architecture of the bone marrow and confirm diagnoses. Potential complications of either bone marrow aspiration or biopsy include bleeding and infection. The risk of bleeding is somewhat increased if the patient's platelet count is low or if the patient has been taking a medication that alters platelet function (e.g., aspirin). After the marrow sample is obtained, pressure is applied to the site for several minutes. The site is then covered with a sterile dressing. Most patients have no discomfort after a bone marrow aspiration, but the site of a biopsy may ache for 1 or 2 days. Warm tub baths and a mild analgesic agent (e.g., acetaminophen) may be useful. Aspirin-containing analgesic agents should be avoided in the immediate postprocedure period because they can aggravate or potentiate bleeding. Also, no rigorous activity or exercise for 1 to 2 days is recommended

Erythopoiesis

Erythroblasts arise from the primitive myeloid stem cells in bone marrow. The erythroblast is an immature nucleated cell that gradually loses its nucleus. At this stage, the cell is known as a reticulocyte. Further maturation into an erythrocyte entails the loss of the dark-staining material within the cell and slight shrinkage. The mature erythrocyte is then released into the circulation. Under conditions of rapid erythropoiesis (i.e., erythrocyte production), reticulocytes and other immature cells may be released prematurely into the circulation. This is often seen when the liver or spleen takes over as the site of erythropoiesis and more nucleated red cells appear within the circulation. Differentiation of the primitive myeloid stem cell into an erythroblast is stimulated by erythropoietin, a hormone produced primarily by the kidney. If the kidney detects low levels of oxygen, as occurs when fewer red cells are available to bind oxygen (i.e., anemia), or with people living at high altitudes with lower atmospheric oxygen concentrations, erythropoietin levels increase. The increased erythropoietin then stimulates the marrow to increase the production of erythrocytes. The entire process of erythropoiesis occurs over 1 week (Wimberly, 2019). For normal erythrocyte production, the bone marrow also requires iron, vitamin B12, folate, pyridoxine (vitamin B6), protein, and other factors. A deficiency of these factors during erythropoiesis can result in decreased red cell production and anemia.

Pharmacologic

Erythropoietin- Chronic anemia secondary to diminished erythropoietin- CKD Used for patients who are anemic from chemotherapy or zidovudine (AZT) therapy and for those who have diseases involving bone marrow suppression, such as myelodysplastic syndrome (MDS). The use of erythropoietin can also enable a patient to donate several units of blood for future use (e.g., preoperative autologous donation). The medication can be administered IV or subcutaneously, although plasma levels are better sustained with the subcutaneous route. Side effects are rare, but erythropoietin can cause or exacerbate hypertension. If the anemia is corrected too quickly or is overcorrected, the elevated hematocrit can cause headache and, potentially, seizures. Thrombosis has been noted in some patients whose hemoglobins were raised to a high level; thus, it is recommended that a target hemoglobin level of less than 12 g/dL be used. These adverse effects are rare except for patients with renal failure. Serial complete blood counts (CBCs) must be performed to evaluate the response to the medication. The dose and frequency of administration are titrated to the hemoglobin level. Granulocyte Colony-Stimulating Factor (G-CSF) G-CSF (filgrastim) is a cytokine that stimulates the proliferation and differentiation of myeloid stem cells; a rapid increase in neutrophils is seen within the circulation. G-CSF is effective in improving transient but severe neutropenia after chemotherapy or in some forms of MDS. It is particularly useful in preventing bacterial infections that would be likely to occur with neutropenia. G-CSF is given subcutaneously on a daily basis. The primary side effect is bone pain; this probably reflects the increase in hematopoiesis within the marrow. Serial CBCs should be performed to evaluate the response to the medication and to ensure that the rise in white blood cells is not excessive. The effect of G-CSF on myelopoiesis is short; the neutrophil count drops once the medication is stopped.

Complications of blood donation

Excessive bleeding at the donor's venipuncture site is sometimes caused by a bleeding disorder but more often results from a technique error: laceration of the vein, excessive tourniquet pressure, or failure to apply enough pressure after the needle is withdrawn. Fainting may occur after blood donation and may be related to emotional factors, a vasovagal reaction, or prolonged fasting before donation. Because of the loss of blood volume, hypotension and syncope may occur when the donor assumes an erect position A donor who appears pale or complains of faintness should immediately lie down or sit with the head lowered below the knees. The donor should be observed for another 30 minutes. Anginal chest pain may be precipitated in patients with unsuspected coronary artery disease. Seizures can occur in donors with epilepsy, although the incidence is very low. Both angina and seizures require further medical evaluation and treatment.

Preparations

Factor VIII concentrate (antihemophilic factor) is a lyophilized, freeze-dried concentrate of pooled fractionated human plasma used in treating hemophilia A. Factor IX concentrate (prothrombin complex) is similarly prepared and contains factors II, VII, IX, and X. It is used primarily for the treatment of factor IX deficiency (hemophilia B). Factor IX concentrate is also useful in treating congenital factor VII and factor X deficiencies. Recombinant forms of factor VIII, such as Humate-P or Alphanate, are also useful. Because they contain von Willebrand factor, these agents are used in von Willebrand disease as well as in hemophilia A, particularly when patients develop factor VIII inhibitors. Plasma albumin is a large protein molecule that usually stays within vessels and is a major contributor to plasma oncotic pressure. This protein is used to expand the blood volume of patients in hypovolemic shock and, rarely, to increase the concentration of circulating albumin in patients with hypoalbuminemia. Immune globulin is a concentrated solution of the antibody immunoglobulin G (IgG), prepared from large pools of plasma. It contains very little immunoglobulin A (IgA) or IgM. Intravenous immunoglobulin (IVIG) is used in various clinical situations to replace inadequate amounts of IgG in patients who are at risk for recurrent bacterial infection (e.g., those with chronic lymphocytic leukemia, those receiving HSCT). It is also used in certain autoimmune disorders, such as idiopathic thrombocytopenic purpura (ITP). Albumin, antihemophilic factors, and IVIG, in contrast to all other fractions of human blood, cells, or plasma, can survive being subjected to heating at 60°C (140°F) for 10 hours to free them of the viral contaminants that may be present.

Pharmacologic

Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) GM-CSF (sargramostim) is a cytokine that is naturally produced by a variety of cells, including monocytes and endothelial cells. It works either directly or synergistically with other growth factors to stimulate myelopoiesis. GM-CSF is not as specific to neutrophils as is G-CSF; thus, an increase in erythroid (red blood cell) and megakaryocytic (platelet) production may also be seen. GM-CSF serves the same purpose as G-CSF. However, it may have a greater effect on macrophage function and therefore may be more useful against fungal infections, whereas G-CSF may be better used to fight bacterial infections. GM-CSF is also given subcutaneously. Side effects include bone pain, fevers, and myalgias. Thrombopoietin Thrombopoietin (TPO) is a cytokine that is necessary for the proliferation of megakaryocytes and subsequent platelet formation. Nonimmunogenic second-generation thrombopoietic growth factors (romiplostim; eltrombopag) are used for the treatment of idiopathic thrombocytopenic purpura. Eltrombopag is also approved for use in certain situations for patients with aplastic anemia and in patients requiring hepatitis C treatment that can cause significant thrombocytopenia.

Physical assessment

Gray-tan or bronze skin color (especially genitalia, scars, exposed areas) Hemochromatosis (primary or secondary) Ruddy complexion (face, conjunctiva, hands, feet) Polycythemia Ecchymoses (i.e., bruises) Thrombocytopenia, coagulopathy Petechiae (i.e., pinpoint hemorrhagic lesions, usually more prominent on trunk or anterior aspects of lower extremities) Severe thrombocytopenia Rash Variable; if pruritic, may indicate polycythemia, other non-hematologic-related disorders Bleeding (including around vascular lines, tubes) Thrombocytopenia, coagulopathy Conjunctival hemorrhage Severe thrombocytopenia, coagulopathy Pallor, especially in mucous membranes (including conjunctiva), nail beds Anemia Jaundice in mucous membranes (including conjunctiva), nail beds, palate Hemolysis Petechiae in the buccal mucosa, gingiva, hard palate Severe thrombocytopenia Ulceration of oral mucosa Infection, leukemia Tongue: Smooth Pernicious anemia Beefy red Enlarged Vitamin B12/folate deficiency Amyloidosis Angular cheilosis (ulceration at corners of mouth) Anemia Enlarged gums: hyperplasia Leukemia Lymph nodes Enlarged size, firm and fixed vs. mobile and tender Leukemia, lymphoma

Hematopoietic stem cell transplantation

Hematologic disorders such as severe aplastic anemia, some forms of leukemia, and thalassemia. It can also provide longer remission from disease even when cure is not possible, such as in multiple myeloma. Hematopoietic stem cells may be transplanted from either allogeneic or autologous donors. For most hematologic diseases, allogeneic transplant is more effective Patient's own stem cells are harvested and used in autologous transplant

Transfusion related acute lung injury

Idiosyncratic reaction that is defined as the development of acute lung injury occurring within 6 hours after the blood transfusion. All blood components have been implicated in TRALI, including IVIG, cryoprecipitate, and stem cells. TRALI is the most common cause of transfusion-related death Thought to involve specific human leukocyte antigen (HLA) or human neutrophil antigen (HNA) antibodies in the donor's plasma that react to the leukocytes in the recipient's blood. Occasionally, the reverse occurs, and antibodies present in the recipient's plasma agglutinate the antigens on the few remaining leukocytes in the blood component being transfused. Another theory suggests that an initial insult to the patient's vascular endothelium can predispose the neutrophils to aggregate at the injured endothelium. Various substances within the transfused blood component (lipids, cytokines) then activate these neutrophils. Each of these pathophysiologic mechanisms can contribute to the process. The end result of this process is interstitial and intra-alveolar edema, as well as extensive sequestration of WBCs within the pulmonary capillaries Onset is abrupt (usually within 6 hours of transfusion, often within 2 hours). Signs and symptoms include acute shortness of breath, hypoxia (arterial oxygen saturation [SaO2] less than 90%; partial pressure of arterial oxygen [PaO2] to fraction of inspired oxygen [FIO2] ratio of less than 300), hypotension, fever, and eventual pulmonary edema. Diagnostic criteria include hypoxemia, bilateral pulmonary infiltrates (seen on chest x-ray), no evidence of cardiac cause for the pulmonary edema, and no other plausible alternative cause within 6 hours of completing transfusion. Aggressive supportive therapy (e.g., oxygen, intubation, fluid support) may prevent death. Immunologic therapy (e.g., corticosteroids) has not been shown to be effective in this setting; diuretics can worsen the situation Although TRALI can occur with the transfusion of any blood component, it is more likely to occur when plasma and, to a lesser extent, platelets are transfused. One commonly used preventive strategy involves limiting the frequency and amount of blood products transfused. Another entails obtaining plasma and possibly platelets only from men because women who have been pregnant may have developed offending antibodies. A third strategy involves screening donors for the presence of these antibodies and discarding any plasma-containing blood products from those donors who screen positive. The efficacy of these approaches in preventing TRALI remains unclear

Transfusion associated circulatory overload

If too much blood is infused too quickly, hypervolemia can occur. This condition, known as transfusion-associated circulatory overload (TACO), can be aggravated in patients who already have increased circulatory volume (e.g., those with heart failure, renal dysfunction, advanced age, acute myocardial infarction) A careful assessment for signs of circulatory overload or positive fluid status prior to initiating the transfusion is required, particularly in patients at risk for developing transfusion-related acute lung injury (TRALI) (see discussion below). PRBCs are safer to use than whole blood. If the administration rate is sufficiently slow, circulatory overload may be prevented. For patients who are at risk for, or already in, circulatory overload, diuretics are given prior to the transfusion or between units of PRBCs. Patients receiving fresh-frozen plasma or even platelets may also develop circulatory overload. The infusion rate of these blood components must also be titrated to the patient's tolerance. Rates of transfusion may need to decrease to less than 100 to 120 mL/h Signs of circulatory overload include dyspnea, orthopnea, tachycardia, an increase in blood pressure, and sudden anxiety. Jugular vein distention, crackles at the base of the lungs, and hypoxemia will also develop. Pulmonary edema can quickly develop, as manifested by severe dyspnea and coughing of pink, frothy sputum. If fluid overload is mild, the transfusion can often be continued after slowing the rate of infusion and administering diuretics. However, if the overload is severe, the patient is placed upright with the feet in a dependent position, the transfusion is discontinued, and the primary provider is notified. The IV line is kept patent with a very slow infusion of normal saline solution or a saline lock device to maintain access to the vein in case IV medications are necessary. Oxygen and morphine may be needed to treat severe dyspnea Develop as late as 6 hours Patients need close monitoring after the transfusion is completed, particularly those who are at higher risk for developing this complication (e.g., older adults, those with a positive fluid balance prior to transfusion, patients with renal dysfunction, patients with left ventricular dysfunction). Monitoring vital signs, auscultating breath sounds, and assessing for jugular venous distention should be included in patient monitoring.

Gerontologic considerations

In older adults, the bone marrow's ability to respond to the body's need for blood cells (erythrocytes, leukocytes, and platelets) may be decreased, resulting in leukopenia (a decreased number of circulating leukocytes) or anemia. This decreased ability is a result of many factors, including diminished production of the growth factors necessary for hematopoiesis by stromal cells within the marrow or a diminished response to the growth factors (in the case of erythropoietin). Over time, stem cells within the marrow acquire damage to their DNA, which compromises their function. T- and B-cell development is also decreased. This age-related decrease in immune system response due to diminished production and function of blood cells designed to protect the body is called immunosenescence

Leukocytes

Leukocytes are divided into two general categories: granulocytes and lymphocytes. In normal blood, the total leukocyte count is 4000 to 11,000 cells/mm3. Of these, approximately 60% to 80% are granulocytes and 20% to 40% are lymphocytes. Both of these types of leukocytes primarily protect the body against infection and tissue injury. Granulocytes-Granulocytes are divided into three main subgroups—eosinophils, basophils, and neutrophils—that are characterized by the staining properties of these granules. Eosinophils have bright-red granules in their cytoplasm, whereas the granules in basophils stain deep blue. The third and most numerous cell in this class is the neutrophil, with granules that stain a pink to violet hue. Neutrophils are also called polymorphonuclear neutrophils (PMNs, or polys) or segmented neutrophils (segs). The nucleus of the mature neutrophil has multiple lobes (usually two to five) that are connected by thin filaments of nuclear material, or a "segmented" nucleus; it is usually two times the size of an erythrocyte. The somewhat less mature granulocyte has a single-lobed, elongated nucleus and is called a band cell. Ordinarily, band cells account for only a small percentage of circulating granulocytes, although their percentage can increase greatly under conditions in which neutrophil production increases, such as infection. The increased number of band cells is sometimes called a left shift or shift to the left. (Traditionally, the diagram of neutrophil maturation showed the myeloid stem cell on the left with progressive maturation stages toward the right, ending with a fully mature neutrophil on the far right side. A shift to the left indicates that more immature cells are present in the blood than normal.) Fully mature neutrophils result from the gradual differentiation of myeloid stem cells, specifically myeloid blast cells (i.e., immature white blood cells). The process, called myelopoiesis, is highly complex and depends on many factors. These factors, including specific cytokines (i.e., regulatory proteins produced by leukocytes) such as growth factors, are normally present within the marrow itself. As the blast cell matures, the cytoplasm of the cell changes in color (from blue to violet) and granules begin to form with the cytoplasm. The shape of the nucleus also changes. The entire process of maturation and differentiation takes about 10 days. Once the neutrophil is released into the circulation from the marrow, it stays there for only about 6 hours before it migrates into the body tissues to perform its function of phagocytosis (ingestion and digestion of foreign bodies, such as bacteria). Neutrophils die here within 1 to 2 days. The number of circulating granulocytes found in the healthy person is relatively constant; however, in infection, large numbers of these cells are rapidly released into the circulation.

Agranulocytes

Monocytes (also called mononuclear leukocytes) are leukocytes with a single-lobed nucleus and a granule-free cytoplasm—hence the term agranulocyte. In normal adult blood, monocytes account for approximately 5% of the total leukocytes. Monocytes are the largest of the leukocytes. Produced by the bone marrow, they remain in the circulation for a short time before entering the tissues and transforming into macrophages. Macrophages are particularly active in the spleen, liver, peritoneum, and alveoli; they remove debris from these areas and phagocytize bacteria within the tissues.

Diagnostic

Most hematologic diseases reflect a defect in the hematopoietic, hemostatic, or reticuloendothelial systems. The defect can be quantitative (e.g., increased or decreased production of cells), qualitative (e.g., the cells that are produced are defective in their expected functional capacity), or both. Initially, many hematologic conditions cause few symptoms, and extensive laboratory tests are often required to establish a diagnosis. For most hematologic conditions, continued monitoring via specific blood tests is required because it is very important to assess for changes in test results over time. In general, it is important to assess trends in test results because these trends help the clinician decide whether the patient is responding appropriately to interventions.

Procedure

Obtain packed red blood cells (PRBCs) from the blood bank after the IV line is started. (Institution policy may limit release to only 1 unit at a time.) 2.Double-check labels with another nurse or physician to ensure that the ABO group and Rh type agree with the compatibility record. Check to see that number and type on donor blood label and on patient's medical record are correct. Confirm patient's identification by asking the patient's name and checking the identification wristband. 3.Check blood for gas bubbles and any unusual color or cloudiness. (Gas bubbles may indicate bacterial growth. Abnormal color or cloudiness may be a sign of hemolysis.) 4.Make sure that PRBC transfusion is initiated within 30 minutes after removal of PRBCs from blood bank refrigerator. 5.For the first 15 minutes, run the transfusion slowly—no faster than 5 mL/min. Observe patient carefully for adverse effects. If no adverse effects occur during the first 15 minutes, increase the flow rate unless patient is at high risk for circulatory overload. 6.Monitor closely for 15 to 30 minutes to detect signs of reaction. Monitor vital signs at regular intervals per institution or agency policy; compare results with baseline measurements. Increase frequency of measurements based on patient's condition. Observe patient frequently throughout the transfusion for any signs of adverse reaction, including restlessness, hives, nausea, vomiting, torso or back pain, shortness of breath, flushing, hematuria, fever, or chills. Should any adverse reaction occur, stop infusion immediately, notify primary provider, and follow the agency's transfusion reaction standard. 7.Note that administration time does not exceed 4 hours because of increased risk of bacterial proliferation. 8.Be alert for signs of adverse reactions: circulatory overload, sepsis, febrile reaction, allergic reaction, and acute hemolytic reaction. 9.Change blood tubing after every 2 units transfused to decrease chance of bacterial contamination.

Procedure

Obtain platelets or fresh-frozen plasma (FFP) from the blood bank (only after the IV line is started.) 2.Double-check labels with another nurse or physician to ensure that the ABO group matches the compatibility record (not usually necessary for platelets; here only if compatible platelets are ordered). Check to see that the number and type on donor blood label and on patient's medical record are correct. Confirm patient's identification by asking the patient's name and checking the identification wristband. 3.Check blood product for any unusual color or clumps (excessive redness indicates contamination with larger amounts of red blood cells). 4.Make sure that platelets or FFP units are given immediately after they are obtained. 5.Infuse each unit of FFP over 30 to 60 minutes per patient tolerance; be prepared to infuse at a significantly lower rate in the context of fluid overload. Infuse each unit of platelets as fast as patient can tolerate to diminish platelet clumping during administration. Observe patient carefully for adverse effects, especially circulatory overload. Decrease rate of infusion if necessary. 6.Observe patient closely throughout transfusion for any signs of adverse reaction, including restlessness, hives, nausea, vomiting, torso or back pain, shortness of breath, flushing, hematuria, fever, or chills. Should any adverse reaction occur, stop infusion immediately, notify primary provider, and follow the agency's transfusion reaction standard. 7.Monitor vital signs at the end of transfusion per institution policy; compare results with baseline measurements. 8.Flush line with saline after transfusion to remove blood component from tubing.

Postprocedure

Obtain vital signs and auscultate breath sounds; compare with baseline measurements. If signs of increased fluid overload present, consider obtaining prescription for diuretic, as warranted. 2.Dispose of used materials properly. 3.Document procedure in patient's medical record, including patient assessment findings and tolerance to procedure. 4.Monitor patient for response to and effectiveness of procedure. A platelet count may be ordered 1 hour after platelet transfusion to facilitate this evaluation. 5.If patient is at risk for transfusion-associated circulatory overload (TACO), monitor closely for 6 hours after transfusion if possible.

Postprocedure

Obtain vital signs and breath sounds; compare with baseline measurements. If signs of increased fluid overload present (e.g., heart failure), consider obtaining prescription for diuretic as warranted. 2.Dispose of used materials properly. 3.Document procedure in patient's medical record, including patient assessment findings and tolerance to procedure. 4.Monitor patient for response to and effectiveness of procedure. If patient is at risk, monitor for at least 6 hours for signs of transfusion-associated circulatory overload (TACO); also monitor for signs of delayed hemolytic reaction. Note: Never add medications to blood or blood products; if blood is too thick to run freely, normal saline may be added to the unit. If blood must be warmed, use an in-line blood warmer with a monitoring system.

Diagnostic

Other common tests of coagulation are the prothrombin time (PT), typically replaced by the standardized test, international normalized ratio (INR), and the activated partial thromboplastin time (aPTT). The INR and aPTT serve as useful screening tools for evaluating a patient's clotting ability and monitoring the therapeutic effectiveness of anticoagulant medications. In both tests, specific reagents are mixed into the plasma sample, and the time taken to form a clot is measured. For these tests to be accurate, the test tube must be filled with the correct amount of the patient's blood; either excess or inadequate blood volume within the tube can render the results inaccurate.

Pretransfusion

Patient Hx- The history should include the type of reaction, its manifestations, the interventions required, and whether any preventive interventions were used in subsequent transfusions. The nurse assesses the number of pregnancies a woman has had, because a high number can increase her risk of reaction due to antibodies developed from exposure to fetal circulation. Other concurrent health problems should be noted, with careful attention to cardiac, pulmonary, and vascular disease. Informed consent must be obtained preprocedure Physical assessment-A systematic physical assessment and measurement of baseline vital signs and fluid status are important before transfusing any blood product. The respiratory system should be assessed, including careful auscultation of the lungs and the patient's use of accessory muscles. Cardiac system assessment should include careful inspection for any edema as well as other signs of heart failure (e.g., jugular venous distention) Skin- rashes, petechiae, and ecchymoses The sclera should be examined for icterus. In the event of a transfusion reaction, a comparison of findings can help differentiate between types of reactions.

Standard Donation

Phlebotomy consists of venipuncture and blood withdrawal. Standard precautions are used. Donors are placed in a semirecumbent position. The skin over the antecubital fossa is carefully cleansed with an antiseptic preparation, a tourniquet is applied, and venipuncture is performed. Withdrawal of 450 mL of blood usually takes less than 15 minutes. After the needle is removed, donors are asked to hold the involved arm straight up, and firm pressure is applied with sterile gauze for 2 to 3 minutes. A firm bandage is then applied. The donor remains recumbent until they feel able to sit up, usually within a few minutes. Donors who experience weakness or faintness should rest for a longer period. The donor then receives food and fluids and is asked to remain another 15 minutes. The donor is instructed to leave the dressing on and to avoid heavy lifting for several hours, to avoid smoking for 1 hour, to avoid drinking alcoholic beverages for 3 hours, to increase fluid intake for 2 days, and to eat healthy meals for at least 2 weeks. Specimens from the donated blood are tested to detect infections and to identify the specific blood type

Platelets (thrombocytes)

Platelets, or thrombocytes, are not technically cells; rather, they are granular fragments of giant cells in the bone marrow called megakaryocytes. Platelet production in the marrow is regulated in part by the hormone thrombopoietin, which stimulates the production and differentiation of megakaryocytes from the myeloid stem cell. Each megakaryocyte has the capacity to produce approximately 2000 platelets; 80% of these platelets are active in the circulation and 20% are stored in the spleen. Platelets play an essential role in the control of bleeding. They circulate freely in the blood in an inactive state, where they nurture the endothelium of the blood vessels, maintaining the integrity of the vessel. When vascular injury occurs, platelets collect at the site and are activated. They adhere to the site of injury and to each other, forming a platelet plug that temporarily stops bleeding. Substances released from platelet granules activate coagulation factors in the blood plasma and initiate the formation of a stable clot composed of fibrin, a filamentous protein. Platelets have a normal lifespan of 7 to 10 days

Hemostasis

Preventing blood loss from intact vessels and of stopping bleeding from a severed vessel, which requires adequate numbers of functional platelets. Platelets nurture the endothelium and thereby maintain the structural integrity of the vessel wall. Two processes are involved in arresting bleeding: primary and secondary hemostasis. In primary hemostasis, the severed blood vessel constricts. Circulating platelets aggregate at the site and adhere to the vessel and to one another. An unstable hemostatic plug is formed. For the coagulation process to be correctly activated, circulating inactive coagulation factors must be converted to active forms. This process occurs on the surface of the aggregated platelets at the site of vessel injury. The end result is the formation of fibrin, which reinforces the platelet plug and anchors it to the injury site. This process is referred to as secondary hemostasis. Blood coagulation is highly complex. It can be activated by the extrinsic pathway (also known as the tissue factor pathway) or the intrinsic pathway (also known as the contact activation pathway). Both pathways are needed for maintenance of normal hemostasis. Many factors are involved in the reaction cascade that forms fibrin. When tissue is injured, the extrinsic pathway is activated by the release of thromboplastin from the tissue. As the result of a series of reactions, prothrombin is converted to thrombin, which in turn catalyzes the conversion of fibrinogen to fibrin. Clotting by the intrinsic or contact activation pathway is activated when the collagen that lines blood vessels is exposed. Clotting factors are activated sequentially until, as with the extrinsic pathway, fibrin is ultimately formed The intrinsic pathway is slower, and this sequence is less often responsible for clotting in response to tissue injury. However, it is important if a noninjured vessel wall comes into contact with lipoproteins (e.g., atherosclerosis) or with bacteria, resulting in a clot that is formed for purposes other than protection from trauma or bleeding. As the injured vessel is repaired and again covered with endothelial cells, the fibrin clot is no longer needed. The fibrin is digested via two systems: the plasma fibrinolytic system and the cellular fibrinolytic system. The protein plasminogen is required to lyse (break down) the fibrin. Plasminogen, which is present in all body fluids, circulates with fibrinogen and is therefore incorporated into the fibrin clot as it forms. When the clot is no longer needed (e.g., after an injured blood vessel has healed), the plasminogen is activated to form plasmin. Plasmin digests the fibrinogen and fibrin. The breakdown particles of the clot, called fibrin degradation products, are released into the circulation. Through this system, clots are dissolved as tissue is repaired, and the vascular system returns to its normal baseline state.

Health history

Prior episodes of bleeding (epistaxis, tooth, gum, hematuria, menorrhagia, hematochezia, gastrointestinal bleeding and/or ulcers) Thrombocytopenia, coagulopathy, anemia Prior blood clots, pulmonary emboli, miscarriages Thrombotic disorder Fatigue and weakness Anemia, infection, malignancy, clonal disorders Dyspnea, particularly dyspnea on exertion, orthopnea, shortness of breath Anemia, infection Prior radiation therapy (especially pelvic irradiation) Anemia, pancytopenia, myelodysplastic syndrome, leukemia Prior chemotherapy Myelodysplastic syndrome, leukemia Hobbies/occupational/military exposure history (especially benzene, Agent Orange) Myelodysplastic syndrome, leukemia, myeloma, lymphoma Diet history Anemia (due to vitamin B12, folate, iron deficiency) Alcohol consumption Anemia (effect on hematopoiesis, nutritional deficiency) Use of herbal supplements Platelet dysfunction Concurrent medications Neutropenia, anemia, hemolysis, thrombocytopenia Family history/ethnicity Some hematologic disorders have a higher prevalence in certain ethnic groups and families

Assessment

Respiratory Increased rate and depth of respirations; adventitious breath sounds Anemia; infection Cardiovascular Distended neck veins, edema, chest pain on exertion, murmurs, gallops Hypotension (below baseline) Hypertension (above baseline) Severe anemia Polycythemia Genitourinary Hematuria Hemolysis, thrombocytopenia Proteinuria Myeloma Musculoskeletal Rib/sternal tenderness to palpation Leukemia, myeloma Back pain; tenderness to palpation over spine, loss of height, kyphosis Myeloma Pain/swelling in knees, wrists, hands Hemophilia, sickle cell disease Abdominal Enlarged spleen Leukemia, myelofibrosis Enlarged liver Myelofibrosis Stool positive for occult blood Anemia, thrombocytopenia Central nervous system Cranial nerve dysfunction Vitamin B12 deficiency Peripheral nerve dysfunction (especially sensory) Visual changes, headache, alteration in mental status Vitamin B12 deficiency, amyloidosis, myeloma Severe thrombocytopenia Gynecologic Menorrhagia Thrombocytopenia, coagulopathy Constitutional Fever, chills, sweats, asthenia Leukemia, lymphoma; infection

Patient educations

Reviewing the signs and symptoms of a transfusion reaction is crucial with all patients, including those who have and have not received a previous transfusion. Signs and symptoms of a reaction include fever, chills, respiratory distress, low back pain, nausea, pain at the IV site, or anything "unusual." Although a thorough review is very important, the nurse also reassures the patient that the blood is carefully tested against the patient's own blood (cross-matched) to diminish the likelihood of any untoward reaction. Similarly, the patient can be reassured about the very low possibility of contracting HIV from the transfusion; this fear persists among many people.

Blood processing

Samples of the unit of blood are always taken immediately after donation so that the blood can be typed and tested. Each donation is tested for antibodies to human immune deficiency virus (HIV) types 1 and 2, hepatitis B core antibody (anti-HBc), hepatitis C virus (HCV), human T-cell lymphotropic virus type I (anti-HTLV-I/II), hepatitis B surface antigen (HbsAG), and syphilis. Negative reactions are required for the blood to be used, and each unit of blood is labeled to certify the results. Nucleic acid amplification testing has increased the ability to detect the presence of HCV, HIV, and West Nile virus infections, because it directly tests for genomic nucleic acids of the viruses rather than for the presence of antibodies to the viruses. This testing significantly shortens the "window" of inability to detect HIV and HCV from a donated unit, further ensuring the safety of the blood Blood is also screened for cytomegalovirus (CMV). If it tests positive for CMV, it can still be used, except in recipients who are negative for CMV and who are severely immunocompromised; any components are labeled as CMV positive. Equally important is accurate determination of the blood type. More than 200 antigens have been identified on the surface of RBC membranes. Of these, the most important for safe transfusion are the ABO and Rh systems. The ABO system identifies which sugars are present on the membrane of a person's erythrocytes: A, B, both A and B, or neither A nor B (type O). To prevent a significant reaction, the same type of PRBCs should be transfused. Previously, it was thought that in an emergency situation in which the patient's blood type was not known, type O blood could be safely transfused. This practice is no longer recommended. Rh antigen or D-Those who lack the D antigen are referred to as being Rh negative. PRBCs are routinely tested for the D antigen as well as ABO. Patients should receive PRBCs with a compatible Rh type.

Therapeutic Apheresis

Separation -Apheresis In therapeutic apheresis (or pheresis), blood is taken from the patient and passed through a centrifuge, where a specific component is separated from the blood, removed The entire system is closed, so the risk of bacterial contamination is low. When platelets or leukocytes are removed, the decrease in these cells within the circulation is temporary. Platelet donors can have their platelets apheresed as often as every 14 days. Leukocytes can be obtained similarly, typically after the donor has received growth factors (granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor) to stimulate the formation of additional leukocytes and thereby increase the leukocyte count. The use of these growth factors also stimulates the release of stem cells within the circulation. Apheresis is used to harvest these stem cells (typically over a period of several days) for use in peripheral blood stem cell transplant Removal of plasma is plasmapheresis

RBC destruction

The average lifespan of a normal circulating erythrocyte is 120 days. Often, older erythrocytes lose elasticity and become trapped in small blood vessels and the spleen. These older erythrocytes are removed from the blood by the reticuloendothelial cells, particularly in the liver and the spleen. As the erythrocytes are destroyed, most of their hemoglobin is recycled. Some hemoglobin also breaks down to form bilirubin and is secreted in the bile. Most of the iron is recycled to form new hemoglobin molecules within the bone marrow; small amounts are lost daily in the feces and urine and monthly in menstrual flow.

Bone marrow

The bone marrow is the site of hematopoiesis, or blood cell formation. In adults, blood cell formation is usually limited to the pelvis, ribs, vertebrae, and sternum. Marrow is one of the largest organs of the body, making up 4% to 5% of total body weight. It consists of islands of cellular components (red marrow) separated by fat (yellow marrow). As people age, the proportion of active marrow is gradually replaced by fat; however, in healthy adults, the fat can again be replaced by active marrow when more blood cell production is required. In adults with disease that causes marrow destruction, fibrosis, or scarring, the liver and spleen can also resume production of blood cells by a process known as extramedullary hematopoiesis. The marrow is vascular. Within it are primitive cells called stem cells. The stem cells have the ability to self-replicate, thereby ensuring a continuous supply of stem cells throughout the life cycle. When stimulated to do so, stem cells can begin a process called differentiation, and develop into either myeloid or lymphoid stem cells These stem cells are committed to produce specific types of blood cells. Lymphoid stem cells produce either T or B lymphocytes, cells that have specific immune functions that will be described in more detail later. Myeloid stem cells differentiate into three broad cell types: erythrocytes, leukocytes, and platelets. Thus, with the exception of lymphocytes, all blood cells are derived from myeloid stem cells. A defect in a myeloid stem cell can cause problems with erythrocyte, leukocyte, and platelet production. In contrast, a defect in the lymphoid stem cell can cause problems with T or B lymphocytes, plasma cells (a more differentiated form of B lymphocyte), or natural killer (NK) The stroma of the marrow refers to all tissue within the marrow that is not directly involved in hematopoiesis. However, the stroma is important in an indirect manner, in that it produces the colony-stimulating factors needed for hematopoiesis. The yellow marrow is the largest component of the stroma. Other cells comprising the stroma include fibroblasts (reticular connective tissue), osteoclasts, osteoblasts (both needed for remodeling of skeletal bone), and endothelial cells.

Long term transfusion complications

The complications that have been described represent a real risk to any patient any time a blood component is given. However, patients with long-term transfusion requirements (e.g., those with myelodysplastic syndrome, thalassemia, aplastic anemia, sickle cell disease) are at greater risk for infection transmission and for becoming more sensitized to donor antigens, simply because they are exposed to more units of blood and, consequently, more donors. Iron overload is a complication unique to people who have had long-term PRBC transfusions. One unit of PRBCs contains 250 mg of iron. Patients with long-term transfusion requirements can quickly acquire more iron than they can use, leading to iron overload. Over time, the excess iron deposits in body tissues can cause organ damage, particularly in the liver, heart, testes, and pancreas. Promptly initiating a program of iron chelation therapy can prevent end-organ damage from iron toxicity

Introduction

The hematologic system consists of the blood and the sites where blood is produced, including the bone marrow and the reticuloendothelial system (RES). Blood is a specialized organ that differs from other organs in that it exists in a fluid state. Blood is composed of plasma and various types of cells which account for 7% to 9% of total blood volume Plasma is the fluid portion of blood; it contains various proteins, such as albumin, globulin, fibrinogen, and other factors necessary for clotting, as well as electrolytes, waste products, and nutrients. About 55% of whole blood volume is plasma

Bacterial contamination

The incidence of bacterial contamination of blood components is very low; however, administration of contaminated products puts the patient at great risk. Contamination can occur at any point during procurement or processing but often results from organisms on the donor's skin. Many bacteria cannot survive in the cold temperatures used to store PRBCs, but some organisms can. Platelets are at greater risk of contamination because they are stored at room temperature. In response to this, blood centers have developed rapid methods of culturing platelet units, thereby diminishing the risk of using a contaminated platelet unit for transfusion Preventive measures include meticulous care in the procurement and processing of blood components. When PRBCs or whole blood is transfused, it should be given within a 4-hour period, because warm room temperatures promote bacterial growth. A contaminated unit of blood product may appear normal, or it may have an abnormal color. The signs of bacterial contamination are fever, chills, and hypotension. These manifestations may not occur until the transfusion is complete, and occasionally not until several hours after the transfusion. As soon as the reaction is recognized, any remaining transfusion is discontinued (see the Nursing Management of Transfusion Reactions section). If the condition is not treated immediately with fluids and broad-spectrum antibiotics, sepsis can occur. Sepsis is treated with IV fluids and antibiotics; corticosteroids and vasopressors are often also necessary

Red blood cells

The membrane of the red cell is very thin so that gases, such as oxygen and carbon dioxide, can easily diffuse across it; the disc shape provides a large surface area that facilitates the absorption and release of oxygen molecules. Mature erythrocytes consist primarily of hemoglobin, which contains iron and protein and makes up 95% of the cell mass. Mature erythrocytes have no nuclei, and they have many fewer metabolic enzymes than do most other cells. The presence of a large amount of hemoglobin enables the red cell to perform its principal function, which is the transport of oxygen between the lungs and tissues. Occasionally, the marrow releases slightly immature forms of erythrocytes, called reticulocytes, into the circulation. This occurs as a normal response to an increased demand for erythrocytes (as in bleeding) or in some disease states. The oxygen-carrying hemoglobin molecule is made up of four subunits, each containing a heme portion attached to a globin chain. Iron is present in the heme component of the molecule. An important property of heme is its ability to bind to oxygen loosely and reversibly. Oxygen readily binds to hemoglobin in the lungs and is carried as oxyhemoglobin in arterial blood. Oxyhemoglobin is a brighter red than hemoglobin that does not contain oxygen (reduced hemoglobin); thus, arterial blood is a brighter red than venous blood. The oxygen readily dissociates (detaches) from hemoglobin in the tissues, where the oxygen is needed for cellular metabolism. In venous blood, hemoglobin combines with hydrogen ions produced by cellular metabolism and thus buffers excessive acid. Whole blood normally contains about 15 g of hemoglobin per 100 mL of blood

Hematologic studies

The most common tests used are the complete blood count (CBC) and the peripheral blood smear. The CBC identifies the total number of blood cells (leukocytes, erythrocytes, and platelets) as well as the hemoglobin, hematocrit (percentage of blood volume consisting of erythrocytes), and RBC indices. Because cellular morphology (shape and appearance of the cells) is particularly important in accurately diagnosing most hematologic disorders, the blood cells involved must be examined. This process is referred to as the manual examination of the peripheral smear, which may be part of the CBC. In this test, a drop of blood is spread on a glass slide, stained, and examined under a microscope. The shape and size of the erythrocytes and platelets, as well as the actual appearance of the leukocytes, provide useful information in identifying hematologic conditions. Blood for the CBC is typically obtained by venipuncture

Acute hemolytic reaction

The most dangerous, and potentially life-threatening, type of transfusion reaction occurs when the donor blood is incompatible with that of the recipient (i.e., type II hypersensitivity reaction). Antibodies already present in the recipient's plasma rapidly combine with antigens on donor erythrocytes, and the erythrocytes are destroyed in the circulation (i.e., intravascular hemolysis). The most rapid hemolysis occurs in ABO incompatibility. Rh incompatibility often causes a less severe reaction. This reaction can occur after transfusion of as little as 10 mL of PRBCs. Although the overall incidence of such reactions is not high (1:20,000 to 1:40,000 units transfused) The most common causes of acute hemolytic reaction are errors in blood component labeling, a type of clerical error, and errors in patient identification that result in the administration of an ABO-incompatible transfusion. Symptoms consist of fever, chills, low back pain, nausea, chest tightness, dyspnea, and anxiety. As the erythrocytes are destroyed, the hemoglobin is released from the cells and excreted by the kidneys; therefore, hemoglobin appears in the urine (hemoglobinuria). Hypotension, bronchospasm, and vascular collapse may result. Diminished renal perfusion results in acute kidney injury, and disseminated intravascular coagulation may also occur. The reaction must be recognized promptly and the transfusion discontinued immediately Acute hemolytic transfusion reactions are preventable. Meticulous attention to detail in labeling blood samples and blood components and accurately identifying the recipient cannot be overemphasized. Bar coding methods can be useful safeguards in matching a patient's wristband with the label on the blood component; however, these methods are not fail proof and do not reduce the nurse's responsibility to ensure the correct blood component is transfused to the correct patient

Iron and metabolism

The rate of iron absorption is regulated by the amount of iron already stored in the body and by the rate of erythrocyte production. Daily dietary iron requirements vary based on age, gender, and health status. For example, pregnant women require up to 30 mg of iron daily, while adult men require up to 12 mg and children up to 10 mg of iron daily. Additional amounts of iron, up to 2 mg daily, must be absorbed by women of childbearing age to replace that lost during menstruation. Total body iron content in the average adult is approximately 3 g, most of which is present in hemoglobin or in one of its breakdown products. Iron is stored as ferritin and when required, the iron is released into the plasma, binds to transferrin, and is transported into the membranes of the normoblasts (erythrocyte precursor cells) within the marrow, where it is incorporated into hemoglobin. Iron is lost in the feces, either in bile, blood, or mucosal cells from the intestine. Concentration of iron from 50-250 mg/dL With iron deficiency, bone marrow iron stores are rapidly depleted; hemoglobin synthesis is depressed, and the erythrocytes produced by the marrow are small and low in hemoglobin. Iron deficiency in the adult generally indicates blood loss (e.g., from bleeding in the GI tract or heavy menstrual flow). Lack of dietary iron is rarely the sole cause of iron deficiency anemia in adults. The source of iron deficiency should be investigated promptly, because iron deficiency in an adult may be a sign of bleeding in the GI tract or colon cancer.

splenctomy

The surgical removal of the spleen, called splenectomy, is a possible treatment for some hematologic disorders. For example, an enlarged spleen may be the site of excessive destruction of blood cells. In addition, some patients with grossly enlarged spleens develop severe thrombocytopenia as a result of platelets being sequestered in the spleen. Splenectomy removes the "trap," and platelet counts may normalize over time. Laparoscopic splenectomy is associated with decreased postoperative morbidity compared to open splenectomy. Acute risks associated with a splenectomy include hemorrhage, increased clotting, and injury to surrounding organs and tissues. Long-term risks post splenectomy includes greater likelihood to develop life-threatening infections. Patients should be vaccinated for pneumonia before undergoing splenectomy, if possible. The patient is instructed to seek prompt medical attention for even minor symptoms of infection Patients without spleens receive vaccines for influenza, pneumonia, and meningococci. Also, if a patient has other conditions that increase risk of serious infection in addition to a history of splenectomy, they may need antibiotic prophylaxis

Therapeutic phlebotomy

Therapeutic phlebotomy is the removal of a certain amount of blood under controlled conditions. Patients with elevated hematocrits (e.g., those with polycythemia vera) or excessive iron absorption (e.g., hemochromatosis) can usually be managed by periodically removing 1 unit (about 500 mL) of whole blood. Over time, this process can produce iron deficiency, leaving the patient unable to produce as many erythrocytes. The actual procedure for therapeutic phlebotomy is similar to that for blood donation

Hemodilution

This transfusion method may be initiated before or after induction of anesthesia. About 1 to 2 units of blood are removed from the patient through a venous or arterial line and simultaneously replaced with a colloid or crystalloid solution. The blood obtained is then reinfused after surgery. The advantage of this method is that the patient loses fewer erythrocytes during surgery, because the added IV solutions dilute the concentration of erythrocytes and lower the hematocrit. However, patients who are at risk for myocardial injury should not be further stressed by hemodilution. Hemodilution has been associated with adverse outcomes in patients having cardiopulmonary bypass; it has also been linked to tissue ischemia, particularly in the kidneys

Intraop Blood Salvage

This transfusion method provides replacement for patients who cannot donate blood before surgery and for those undergoing vascular, orthopedic, or thoracic surgery. During a surgical procedure, blood lost into a sterile cavity (e.g., hip joint) is suctioned into a cell-saver machine. The whole blood or PRBCs are washed, often with saline solution; filtered; and then returned to the patient as an IV infusion. Salvaged blood cannot be stored, because bacteria cannot be completely removed from the blood and thus cannot be used when it is contaminated with bacteria. The use of intraoperative blood salvage has decreased the need for autologous blood donation but has not affected the need for allogeneic blood products

Vitamin B12 and folate metabolism

Vitamin B12 and folate are required for the synthesis of deoxyribonucleic acid (DNA) in RBCs. Both vitamin B12 and folate are derived from the diet. Folate is absorbed in the proximal small intestine, but only small amounts are stored within the body. If the diet is deficient in folate, stores within the body quickly become depleted. Because vitamin B12 is found only in foods of animal origin, strict vegetarians may ingest little vitamin B12. Vitamin B12 combines with intrinsic factor produced in the stomach. The vitamin B12-intrinsic factor complex is absorbed in the distal ileum. People who have had a partial or total gastrectomy may have limited amounts of intrinsic factor, and therefore the absorption of vitamin B12 may be diminished. The effects of either decreased absorption or decreased intake of vitamin B12 are not apparent for 2 to 4 years. Vitamin B12 and folate deficiencies are characterized by the production of abnormally large erythrocytes called megaloblasts. Because these cells are abnormal, many are sequestered (trapped) while still in the bone marrow, and their rate of release is decreased. Some of these cells actually die in the marrow before they can be released into the circulation. This results in megaloblastic anemia.

Blood cells

WBC (Leukocyte) Fights infection Neutrophil Essential in preventing or limiting bacterial infection via phagocytosis Monocyte Enters tissue as macrophage; highly phagocytic, especially against fungus; immune surveillance Eosinophil Involved in allergic reactions (neutralizes histamine); digests foreign proteins Basophil Contains histamine; integral part of hypersensitivity reactions Lymphocyte Integral component of immune system T lymphocyte Responsible for cell-mediated immunity; recognizes material as "foreign" (surveillance system) B lymphocyte Responsible for humoral immunity; many mature into plasma cells to form antibodies Plasma cell Secretes immunoglobulin (antibody); most mature form of B lymphocyte RBC (Erythrocyte) Carries hemoglobin to provide oxygen to tissues; average lifespan is 120 days Platelet (Thrombocyte) Fragment of megakaryocyte; provides basis for coagulation to occur; maintains hemostasis; average lifespan is 10 days

Reticuloendothelial System

When released from the marrow, monocytes spend a short time in the circulation (about 24 hours) and then enter the body tissues. Within the tissues, the monocytes continue to differentiate into macrophages, which can survive for months or years. Macrophages have a variety of important functions. They defend the body against foreign invaders (i.e., bacteria and other pathogens) via phagocytosis. They remove old or damaged cells from the circulation. They stimulate the inflammatory process and present antigens to the immune system Macrophages give rise to tissue histiocytes, phagocytic cells that are present in loose connective tissue. These include Kupffer cells of the liver, peritoneal macrophages, alveolar macrophages, and other components of the RES. Thus, the RES is a component of many other organs within the body, particularly the spleen, lymph nodes, lungs, and liver. The spleen is the site of activity for most macrophages. Most of the spleen (75%) is made of red pulp; here, the blood enters the venous sinuses through capillaries that are surrounded by macrophages. Within the red pulp are tiny aggregates of white pulp, consisting of B and T lymphocytes. The spleen sequesters newly formed reticulocytes from the marrow, removing nuclear fragments and other materials (e.g., damaged or defective hemoglobin, iron) before the now fully mature erythrocyte returns to the circulation. If the spleen is enlarged, a greater number of red cells and platelets can be sequestered. The spleen is a major source of hematopoiesis in fetal life. It can resume hematopoiesis later in adulthood if necessary, particularly when marrow function is compromised (e.g., in bone marrow fibrosis). The spleen has important immunologic functions as well. It forms substances called opsonins that promote the phagocytosis of neutrophils; it also forms the antibody immunoglobulin M (IgM) after exposure to an antigen.

Blood processing

When these errors occur, the patient is transfused an incompatible unit of blood product. Reactions (other than those due to procedural error) are most frequently due to the presence of donor leukocytes within the blood component unit (PRBCs or platelets); the recipient may form antibodies to the antigens present on these leukocytes. PRBC components typically have 1 to 3 × 109 leukocytes remaining in each unit. Leukocytes from the blood product are frequently filtered to diminish the likelihood of developing reactions and refractoriness to transfusions, particularly in patients who have long-term transfusion needs. The process of leukocyte filtration renders the blood component "leukocyte poor" (i.e., leukopoor). Filtration can occur at the time the unit is collected from the donor and processed, which achieves better results but is more expensive, or at the time the blood component is transfused by attaching a leukocyte filter to the blood administration tubing. Many centers advocate routinely using leukopoor filtered blood components for people who have or are likely to develop long-term transfusion requirements. When a patient is immunocompromised, as in the case following stem cell transplant, any donor lymphocytes must be removed from the blood components. In this situation, the blood component is exposed to low amounts of radiation (25 Gy) that kill any lymphocytes within the blood component. Irradiated blood products are highly effective in preventing transfusion-associated graft-versus-host disease, which is fatal in most cases. Irradiated blood products have a shorter shelf life.

Blood and components used in therapy

Whole blood Cells and plasma, hematocrit about 40% Volume replacement and oxygen-carrying capacity; usually used only in significant bleeding (>25% blood volume lost) PRBCs RBCs with little plasma (hematocrit about 75%); some platelets and WBCs remain ↑ RBC mass; symptomatic anemia: •Platelets within the unit are not functional •WBCs within the unit may cause reaction and are not functional Platelets—random Platelets (5.5 × 1010 platelets/unit), plasma; some RBCs, WBCs Bleeding due to severe ↓ platelets Prevent bleeding when platelets <5,000-10,000/mm3 Survival ↓ in presence of fever, chills, infection Repeated treatment leads to ↓ survival due to alloimmunization Platelets—single donor Platelets (3 × 1011 platelets/unit) 1 unit is equivalent to 6-8 units of random platelets Used for repeated treatment: •darr; alloimmunization risk by limiting exposure to multiple donors Plasma Plasma; all coagulation factors Complement Bleeding in patients with coagulation factor deficiencies; plasmapheresis Granulocytes Neutrophils (>1 × 1010/unit); some lymphocytes, RBCs, and platelets will remain within the unit Severe neutropenia in select patients; controversial Lymphocytes Lymphocytes (number varies) Stimulate graft-vs.-host disease effect Cryoprecipitate Fibrinogen ≥150 mg/bag, AHF (VIII:C) 80-110 units/bag, von Willebrand factor; fibronectin von Willebrand disease Hypofibrinogenemia Hemophilia A AHF Factor VIII Hemophilia A Factor IX concentrate Factor IX Hemophilia B (Christmas disease) Factor IX complex Factors II, VII, IX, X Hereditary factor VII, IX, X deficiency; hemophilia A with factor VII inhibitors Albumin Albumin 5%, 25% Hypoproteinemia; burns; volume expansion by 5% to ↑ blood volume; 25% leads to ↓ hematocrit IV gamma-globulin Immunoglobulin G antibodies Hypogammaglobulinemia (in CLL, recurrent infections); ITP; primary immunodeficiency states Antithrombin III concentrate (AT III) AT III (trace amounts of other plasma proteins) AT III deficiency with or at risk for thrombosis