Hanbook of pediatric transfusion medicine - part 2 docx

Acute Normovolemic Hemodilution (ANH) This technique involves WB collection from patients immediately prior to a procedure in which blood loss is anticipated. Rapid replacement of the removed blood volume with crystalloid or colloid solution is done prior to surgery. Re-infusion of the collected blood typically occurs toward the end of the procedure, or as soon as major bleeding has stopped (Goodnough et al. 1992). The reduction of RBC loss during surgery is the purpose of this technique and is sometimes preferred to the cell saver WB collection, which ends up with lower hemat- ocrits than ANH blood products. Postoperative Blood Collection This procedure involves recovery of blood from sur- gical drains and is usually filtered but not always washed before reinfusion. The salvaged product may be hemolyzed and dilute. The product must be transfused within 6 hours or it must be discarded.The primary indi- cations for postoperative blood collection are cardiac and orthopedic surgery cases. PLATELETS Description Two types of platelet components are available to most hospitals in the United States: pooled platelet concentrates (also called “random donor platelets”) and apheresis platelets (also called “single-donor platelets”). Platelet concentrates are derived from WB donations from a single donor. Apheresis platelets are collected via an apheresis device, returning the other WB components to the patient. In addition to the difference in product production, the amount of platelets/unit is also quite distinct. It takes 5 to 8 pooled platelet concentrates (~7 ¥ 10 10 platelets/concentrate) to achieve the same dose of platelets as a single apheresis platelet unit (3 to 6 ¥ 10 11 platelets). As a result, the recipient of pooled platelet concentrates is exposed to 5 to 8 times more blood donors per transfusion than a single apheresis platelet recipient. Additionally, a platelet concentrate unit must undergo leukofiltration to be rendered leukoreduced (WBC <5 ¥ 10 6 ) while an apheresis platelet unit is already “process” leukore- duced (WBC <10 4 to 10 6 ). Finally, RBC contamination is often less in the apheresis product than in WB- derived platelet concentrates; therefore, apheresis platelets may elicit less Rh sensitization. Table 3.2 lists the types of platelet products, with their approximate volumes, compositions, dosing, and storage periods. Indications The normal peripheral blood platelet count is 150,000 to 450,000/mL in premature infants, neonates, children, adolescents, and adults. In premature neonates, the threshold to transfuse is higher than in 3. Blood Components 31 TABLE 3.2 Platelet Products Approximate Neonatal/Pediatric Component Volume (mL) Composition Dosage Storage Period Comments Platelet, apheresis 300 ≥3 ¥ 10 11 Can be dosed at 4 hours if system • Storage 22°–26°C (room (Single donor) platelets; 10 mL/kg body weight, opened (i.e., temp) with constant <10 4 –10 6 but most times is volume reduction horizontal agitation WBCs dosed by 1 / 4 , 1 / 2 , and or washing) • Equivalent to 5–8 units of and plasma whole pheresis units. 5 days (closed platelet concentrates Dose extrapolated back system) • Decreased number donor from adult dose of 1 exposures to patient pheresis for adult BSA • Fewer lymphocytes than 1.7 m 2 –70 kg adult. equivalent dose of platelet concentrates Platelet 50 ≥5.5 ¥ 10 10 Transfused by 4 hours if system • HLA-matched products may concentrate platelets; gravity, pump, or IV opened (i.e., be provided (Random donor) variable push. volume reduction • Cost equivalent to 6–8 units numbers 10 mL/kg body weight or washing) of concentrate RBC, WBCs, transfused by gravity, 5 days (closed • Storage 22°–26°C (room and plasma pump, or IV push. system) temp) with constant horizontal agitation • Average adult dose is 5–8 units, which are pooled for infusion Ch03.qxd 12/19/05 4:12 PM Page 31 other age groups. When the platelet count drops below 10,000/mL there is a clinically significant risk of intracranial hemorrhage, especially in those <1.5 kgs at birth (Andrew et al. 1987). In contrast, most clinically stable, nonbleeding neonates, children, and adolescent patients tolerate platelet counts as low as 5 to 10,000/mL without experiencing major bleeding. Prophylactic transfusions for the prevention of future bleeding remain the most common reason for platelet transfu- sions (Pisciotto et al. 1995). Hanson and Slichter showed that approximately 7000 platelets/mL/day are required to maintain endothelial integrity in normal individuals (Hanson and Slichter 1985). Two recent prospective clinical trials in adults support that the platelet transfusion trigger should be 10,000/mL instead of 20,000/mL in stable patients receiv- ing prophylactic transfusions without coexisting condi- tions (Rebulla et al. 1997; Wandt et al. 1998). However, for patients with fever, active bleeding, or coexisting coagulation defects, a level of 20,000/mL is commonly selected. More detailed indications for platelet transfu- sions, specifically in children, will be covered in Section IV, Chapters 12, 17, 20, and 22. Ordering Informed consent must be obtained before transfu- sion. See the ordering PRBC section on p. 27 for more details. Platelets should be ABO and Rh matched, when possible, in order to attain the best response from the platelet transfusion and decrease the potential for RBC hemolysis. Therefore, the blood bank requires an order to ABO and Rh type the patient before transfusion.This has usually been performed with the type and screen/crossmatch order since PRBCs are often given before, or around the same time as, platelets are admin- istered. However, ABO and Rh matching are not absolutely necessary, and platelet transfusion should not be denied if type-specific platelets are not available.The outcome from giving ABO/Rh incompatible platelets does not have as great a potential to yield a fatal outcome as does ABO/Rh mismatched red cells. Rh immunoglobulin should be administered (estimate 1 mL of PRBC transfused, per platelet concentrate) if the platelet Rh type is mismatched. When ABO- mismatched platelet transfusions occur, they may con- tribute to an eventual platelet refractory state (Carr et al. 1990). Thus, in an attempt to prevent platelet and HLA-alloimmunization, leukoreduced, ABO matched units are recommended. Additionally, hemolysis of RBCs has been reported when patients have received either large volumes of ABO-incompatible plasma or plasma with high-titer isohemagglutinins both of which are more likely to occur with an apheresis platelet product rather than with pooled platelet concentrates (Pierce et al. 1985). Therefore, it is generally recom- mended in the neonate and small child that the platelet products, regardless of type (apheresis or platelet con- centrate), be volume-reduced, to eliminate most of the incompatible plasma, before transfusion. However, since volume-reduction practices have been shown to decrease the number and possibly the function of some of the platelets (as well as reducing the storage time to four hours), the procedure is not routinely recom- mended for older children or adult patients receiving ABO-mismatched platelet products. Further discussion of volume-reduction of platelet products can be found in Section IV, Chapter 22. Dosing Transfusion of 10 mL/kg of a platelet concentrate should provide approximately 10 ¥ 10 9 platelets. Platelets dosed from an apheresis unit at 10 mL/kg may yield a slightly lower dose if more plasma than platelets are pulled into the syringe at the time of making smaller components from the apheresis unit. More often however, platelet apheresis products are ordered as “quarters” or “halves.” Different institu- tions have defined patient subgroups’ weights for the different portions of apheresis platelets. Alternatively, if one estimates that an adult has a body surface area of 1.7 m 2 and is 70 kgs then one can extrapolate to a child and neonate’s body surface area and dose accordingly. Expected Response One way to assess the expected response is to calcu- late the corrected count increment with a 15 minute to 1 hour post platelet count. The corrected count incre- ment (CCI) formula can help the physician determine if his or her patient is platelet refractory or is getting an adequate rise in platelet count based on dose and body surface area. If it is less than 5000 to 7500/mL on 2 successive days, the patient is considered to be refractory. When this sit- uation arises, the blood bank should be notified so they can help with the next steps in providing either cross- matched platelets or HLA-matched platelets. Both spe- cialized products may require hours to days for the blood center to obtain and prepare. Platelet refractory CCI 1 h Post PC – Pre P B Number of Platelets Transfused 10 = ¥ ()( ¥ - r C SA m 2 11 32 Josephson and Hillyer Ch03.qxd 12/19/05 4:12 PM Page 32 states are discussed in greater detail in Section IV, Chapter 22. Contraindications Platelet transfusions have several caveats and/or con- traindications. (1) Surgical or local measures should be pursued first to achieve hemostasis when a single anatomic site is thought responsible for the bleeding. Platelet transfusions are indicated in this situation only if the patient is thrombocytopenic. (2) Surgical inter- vention rather than platelet transfusion is likely needed if hemorrhage of >5 mL/kg/hour is occurring.(3) Throm- botic thrombocytopenic purpura (TTP) and heparin induced thrombocytopenia (HIT) patients should gen- erally not be transfused with platelets, as the addition of platelets may worsen the thrombotic complications. (4) Although not absolutely contraindicated, ITP patients are unlikely to benefit from platelet transfusion due to rapid immune-mediated peripheral platelet destruction. (5) Bleeding uremic patients are usually unresponsive to platelet transfusions alone. However, if administered in conjunction with DDAVP, PRBCs to keep hematocrit >30 g/dL, and/or concurrent dialysis, bleeding uremic patients may respond well to platelet transfusion. Adverse Reactions There are three main adverse reactions that are more specific to platelet transfusion: (1) hypotension, (2) human leukocyte antigen (HLA) and/or human platelet antigen (HPA) alloimmunization, and (3) posttransfu- sion purpura. These reactions will be further detailed in Section VI, Chapters 26–28. Special Processing Leukoreduction, gamma-irradiation, washing, and volume reduction are all special processes relevant to platelets. The reader is referred to Section III, Chapters 7, 9, and 10, and Section IV, Chapter 22. GRANULOCYTES Description Granulocyte collections are mainly performed via automated leukapheresis. The final product is approxi- mately 300 mL in volume and contains, in addition to granulocytes, other elements such as RBCs (6 to 7 g/dL of hemoglobin per granulocyte product), platelets, and citrated plasma.The product is collected from volunteer apheresis donors who receive either corticosteriods (dexamethasone) and/or growth factors such as G-CSF. Oral dexamethasone has been demonstrated to increase baseline peripheral blood granulocytes two- to three- fold (1.7 ¥ 10 9 ), whereas G-CSF stimulated donors have been shown to have a seven- to tenfold increase from baseline (4 to 5 ¥ 10 10 ). The combination of dexam- ethasone and G-CSF has been deemed superior with a 9 to 12 fold increase in circulating granulocytes from baseline. Usually collections are daily for 4 to 5 days. The final granulocyte yield per collection depends upon the total volume of blood processed as well as the start- ing peripheral blood neutrophil count of the donor. Seven to 12 liters of blood are usually processed through a continuous flow blood cell separator over 2 to 4 hours (Price 1995). Indications Clinical indications for granulocyte transfusions include severe neutropenia (<0.5 ¥ 10 9 polymorphonu- clear cells [PMNs]/mL), and the following: (1) progres- sive, nonresponsive, documented bacterial, yeast, or fungal infection nonresponsive to therapy after 48 hours of antimicrobial treatment, (2) a protracted period of neutropenia in stem cell transplant recipients, (3) con- genital granulocyte dysfunction, and (4) bacterial infec- tion in neonates (Klein et al. 1996). These indications will be discussed in greater detail in Chapter 16. It is important to note that the use of prophylactic granulo- cyte transfusion is not recommended (Vamvakas and Pineda 1997). Ordering Granulocytes constitute an unlicensed product and therefore have no official FDA product specifications. However, the American Association of Blood Banks (AABB) standards require the leukapheresis product to contain at least 1 ¥ 10 10 granulocytes ≥75% of units tested (AABB 2003). Ideally, the ordering physician should notify the hospital blood bank who will in turn notify the blood center that a granulocyte transfusion is necessary. The blood center will call potential donors, usually on a known registry, who have the same blood type as the patient. ABO compatibility is required because the granulocyte product has a large volume of RBC con- tamination. A crossmatch is also required prior to administration. Also, as granulocyte products contain a significant number of T-lymphocytes capable of causing TA-GVHD in these immunocompromised recipients, irradiation of all granulocyte products are recom- mended. While likely obvious, the product cannot be leukocyte depleted and should not be infused through a leukocyte reduction filter (Chanock and Gorlin 1996). It 3. Blood Components 33 Ch03.qxd 12/19/05 4:12 PM Page 33 is not necessary to HLA match granulocytes, unless the patient is known to be HLA-alloimmunized. Finally, in most centers an emergency release needs to be signed by the ordering physician as the product needs to be infused soon after collection, a time when the blood supplier has yet to perform all of the infectious disease testing. Dosing For children, the average granulocyte dosage is 1 ¥ 10 9 /kg/day. The neonatal dose average is 1 to 2 ¥ 10 9 /kg (Vamvakas and Pineda 1996). The product is recom- mended to be given for a period of 4 to 7 days to increase the granulocyte count to combat nonantibiotic treatment-responsive infections in severely neutropenic patients. Expected Response It is difficult to accurately predict the posttransfusion increment of granulocytes. A measurement can be made; however, the increment has not been shown to correlate with granulocyte dose given, thus clinical sig- nificance is difficult to assess. The goal is to achieve a sustained granulocyte count above 500 PMN/mL (0.5 ¥ 10 9 /L) after transfusion. This is increasingly possible as the ability to collect large numbers of granulocytes improves. Contraindications Amphotericin B administration concurrent with granulocyte transfusions has been reported to be asso- ciated with pulmonary toxicity. Therefore, granulocyte transfusion is recommended to be separated by at least 4 hours from amphotericin B infusion (Chanock and Gorlin 1996). Adverse Reactions Transfusion reactions, such as fever, dyspnea, rigors, and hypotension, may occur with granulocyte infusions. Reduction of the infusion rate, antihistamines, cortico- steriods, and meperidine may help control these symp- toms (see Chapter 26). PLASMA PRODUCTS Description Plasma, the aqueous, acellular portion of WB, con- sists of proteins, colloids, nutrients, crystalloids, hor- mones, and vitamins. Albumin, the most abundant of the plasma proteins, is discussed on p. 38. Other plasma proteins include complement (C3 predominantly), enzymes, transport molecules, immunoglobulins (gamma-globulins), and coagulation factors. The latter two are also discussed later in this chapter. Coagulation factors in plasma include fibrinogen (2 to 3 mg/mL); factor XIII (60 mg/mL); von Willebrand factor (5 to 10 mg/mL); factor VIII, primarily bound to its carrier protein vWF (approximately 100 ng/mL); and vitamin K-dependent coagulation factors II, VII, IX, X (1 unit of activity/mL for each factor). WB or plasmapheresis collections give rise to several types of plasma products. Single donor plasma or source plasma is produced by plasmapheresis and is stored at -20°C. All other plasma products are derived from WB, and the “time after collection to time of freezing” deter- mines its designation. FFP must be frozen within 6 to 8 hours of collection and stored at -18°C or colder (Brecher 2002). F24 plasma must be frozen within 24 hours of collection and frozen at -18°C or colder. FFP and F24 are considered as essentially equivalent prod- ucts, though factor VIII levels are slightly lower in F24. However, due to factor VIII’s acute phase reactant property, its levels are quickly replenished in recipients without hemophilia A. Furthermore, specific factor VIII concentrates and recombinant factor VIII are available for use in patients with congenital factor VIII deficiency. Thus, FFP and F24 may be used interchangeably in patients without hemophilia A. Another FDA- approved plasma product is cryoreduced plasma (CRP) also, known as cryosupernatant.This product is depleted of its cryoprecipitate fraction; the cryosupernatant is then refrozen at the above temperature. Table 3.3 lists the plasma-derived products, appropriate volumes, composition, and storage periods. Indications The primary use of frozen plasma products (FFP and F24) is for the treatment of coagulation factor deficien- cies in which specific factor concentrates are not avail- able or when immediate hemostasis is critical. Specific indications include: bleeding diatheses associated with acquired coagulation factor deficits, such as end stage liver disease, massive transfusion (Crosson 1996), and disseminated intravascular coagulation (DIC); the rapid reversal of warfarin effect; plasma infusion or exchange for TTP; congenital coagulation defects (except when specific factor therapy is available); and C1-esterase inhibitor deficiency. A more detailed discussion of the indicated uses are addressed in Section IV, Chapters 13, 15, 18, and 20, and Section VII, Chapter 31. 34 Josephson and Hillyer Ch03.qxd 12/19/05 4:12 PM Page 34 Ordering No specific compatibility testing is performed prior to infusion of plasma products. However, the blood bank needs to have an order to ABO type the patient because plasma products must be ABO compatible despite the lack of formal compatibility testing. This requirement exists because plasma contains isohemag- glutinins, which must be compatible with the recipient’s blood type, otherwise hemolysis will ensue. However, if the recipient’s ABO type is unknown prior to plasma infusion, AB plasma may be administered to all recipi- ents, due to its lack of isohemagglutinins. Rh alloimmu- nization rarely occurs due to Rh mismatch of plasma products, as there are few RBCs in the plasma compo- nent. Therefore, Rh compatibility is not as essential as is ABO type when transfusing plasma. Dosing In children and adults, 10 to 20 mL/kg of plasma will usually yield a coagulation factor concentration of approximately 30% of normal. Multiple doses are usually required to correct a clinically significant coag- ulopathy. The infusion can be rapid, if the patient’s 3. Blood Components 35 TABLE 3.3 Plasma-Derived Products Approximate Neonatal/Pediatric Component Volume (mL) Composition Dosage Storage Period Comments Source plasma 180–300 • Plasma proteins 10–15 mL/kg • One year if • Obtained through (Single donor plasma) • Immunoglobulins body weight frozen single donor • Complement transfused over 1 • 24 hours if plasmapheresis • Coagulation hour or IV push maintained at • Stored at -20°C factors (II, VII, 1°–6°C after collection IX, X, VIII, XIII, • Not for volume vWF, fibrinogen) expansion or • Albumin fibrinogen replacement Recovered plasma 180–300 Same as above 10–15 mL/kg • One year if • Plasma obtained body weight frozen from WB of regular transfused over 1 • 24 hours if donor hour or IV push maintained at • Not for volume 1°–6°C expansion or fibrinogen replacement Fresh frozen plasma 180–300 Same as above 10–15 mL/kg • One year if • Separated from WB (FFP) body weight frozen within 6–8 hours of transfused over 1 • 1–5 days collection hour or IV push after thawing • Stored frozen at -18°C • Not for volume expansion or fibrinogen replacement Plasma frozen within 180–300 Same as above 10–15 mL/kg • One year if • Separated from WB 24 hrs (F24) body weight frozen and frozen within 24 transfused over 1 • 1–5 days hours of collection hour or IV push after thawing • Stored frozen at -18°C • Not for volume expansion or fibrinogen replacement Cryoreduced plasma 180–300 Same as above • 1 bag/10 kg • One year if • Depleted of its (CRP) except depleted body weight frozen cryoprecipitate levels of factors • Bags pooled in • 24 hours after fraction VIII, XIII, blood bank thawing fibrinogen, and before vWF transfusion Ch03.qxd 12/19/05 4:12 PM Page 35 cardiovascular status is stable. Timing of repeat doses depends upon the half-life of each factor deficiency being addressed. Contraindications The use of FFP or F24 is not without risk to the reci- pient and should not be used to expand plasma volume, increase plasma albumin concentration, or bolster the nutritional status of malnourished patients. Antithrom- bin (ATIII) or Activated Protein C concentrates may offer an advantage over FFP or F24 use when consid- ering treatment of burns, meningococcal sepsis (Churchwell et al. 1995), or acute renal failure. Adverse Effects Anaphylactic allergic reactions have been attributed to antibodies in the donor’s plasma that react with the recipient’s WBCs, although the reactions are uncom- mon. Furthermore, isohemagglutinins may cause mild to severe hemolytic reactions or result in a positive direct antiglobulin test (Coombs’ test) if “out-of-group” plasma is administered to the patient. Lastly, to avoid life-threatening anaphylaxis, IgA-deficient patients who have formed anti-IgA antibodies must receive IgA- deficient plasma from a national rare donor registry. However, the presence of absolute IgA deficiency with anti-IgA antibodies is an extremely rare occurence and should be confirmed by demonstration of 0% IgA levels using sensitive measures and presence of anti-IgA antibodies before requesting these rare plasma components. CRYOPRECIPITATE Description Cryoprecipitate contains the highest concentrations of factor VIII (80 to 150 U/unit), vWF (100 to 150 U/unit), fibrinogen (150 to 250 U/unit), factor XIII, and fibronectin. Upon thawing FFP (1° and 6°C) an insoluble precipitate is formed, isolated, and is refrozen in 10 to 15 mL of plasma within 1 hour and is termed cryoprecipitate. Storage (£-18°C) is up to 1 year. Before the 1980s, cryoprecipitate was primarily used for the treatment of von Willebrand’s disease and hemo- philia A. However, with the development of recombi- nant factor products and improved viral inactivation procedures, cryoprecipitate’s therapeutic role in treat- ing these diseases has diminished. Presently, fibrinogen replacement is its primary use due to the high fibrino- gen content. Indications Cryoprecipitate has a narrow range of indications, due to the development of safer, more specific factor concentrates. Congenital or acquired fibrinogen defi- ciencies, factor XIII deficiency, DIC, orthotopic liver transplantation, and poststreptokinase therapy (hyper- fibrinogenolysis) are a few of its indicated uses. A more detailed discussion of these uses can be found in Section IV, Chapters 13, 17, and 20. Ordering Cryoprecipitate units have a small volume compared with other plasma products, PRBCs, and apheresis platelets. Thus, anti-A and anti-B isohemagglutinins are present only in small quantities. While the AABB Stan- dards recommend (AABB 2003) ABO compatibility for cryoprecipitate transfusions, especially in pediatric patients, compatibility testing is not required. Further- more, since cryoprecipitate does not contain red cells, Rh matching is not necessary. Dosing Dosing of cryoprecipitate is dependent upon the clin- ical condition being treated. For fibrinogen replace- ment, the most common condition treated with this product, 1 bag/10 kg will increase the fibrinogen level by 60 to 100 mg/dL. However, in a neonate 1 unit will increase fibrinogen by >100 mg/dL. The dosing fre- quency may vary from every 8 to 12 hours to days depending on the cause of hypofibrinogenemia. In von Willebrand’s disease, cryoprecipitate is a second line therapy, and in children 1 unit/6 kg every 12 hours should be administered. In hemophilia A, cryoprecipi- tate is also a second line therapy. If an assumption is made that 1 unit of cryoprecipitate has 100 U factor VIII, then 1 unit/6 kgs will give an approximate factor VIII level of 35% if the patient has <1% at initiation of therapy. The interval for this dosing is discussed in greater detail in Chapter 20. For factor XIII deficiency, due to the low level necessary to achieve hemostasis (2% to 3%), only 1 unit/10 kg every 7 to 14 days is necessary. Contraindications The availability of recombinant factor VIII products, which go through viral inactivation steps unlike cryo- precipitate, have made the use of this product in that disease a relative contraindication. It should only be given if recombinant products are unavailable. 36 Josephson and Hillyer Ch03.qxd 12/19/05 4:12 PM Page 36 Adverse Reactions Refer to FFP adverse reactions. COAGULATION FACTORS Description Before the 1960s, plasma infusion was the only way to treat bleeding disorders. As was described above, plasma contains fibrinogen (I), factor XIII, von Wille- brand factor (vWF), factor VIII, and all of the vitamin- K dependent coagulation factors: II (prothrombin),VII, IX, and X. However, Pool’s discovery in 1964 of high concentrations of factor VIII in cryoprecipitate revolu- tionized the treatment of hemophilia A and eventually vWD (Pool et al. 1964). Subsequently, investigators, with the use of chromatography and monoclonal antibody immunoaffinity technology, were able to produce pro- gressively more purified forms of factor VIII concen- trates. However, the purification techniques did not change the fact that the pooled plasma source could and did transmit viral infection, such as HIV, hepatitis C, hepatitis B, nonenveloped viruses, and other pathogens. In order to create a product free of infectious disease transmission, recombinant DNA technology allowed the production of recombinant coagulation factor prod- ucts via cloning of a desired factor gene and optimiza- tion of an expression system. There are many products used to treat various clot- ting disorders (congenital and acquired) that are either plasma derived or recombinantly produced. Tables 3.4 and 3.5 summariz these products, their manufacturers, and unique characteristics. Indications Various indications for factor replacement exist for each type of factor deficiency. The specifics of thera- peutic indications for various congenital and acquired disorders are addressed in Chapter 20. Ordering The specifics of ordering each product will not be addressed here but can be found in Chapter 20. Gener- ally, however, the ordering physician should be aware of whether he or she desires a plasma-derived product or a recombinantly-derived product.The units and interval of dosing is critical for each factor deficiency because the therapy is necessary to achieve hemostasis, and if underdosed or overdosed the consequences could be fatal. Furthermore, these products are expensive, so more than others, and should not be administered unless absolutely deemed necessary in consultation with either a hemophilia or transfusion medicine specialist. Dosing Dosing of any factor preparation is not only depend- ent on the product being infused but the type of insult being managed. When dosing factor VIII in general the calculation should be based on body weight in kilo- grams and desired factor VIII level to be achieved. This level will vary according to prophylaxis or treatment regimen being employed. Each FVIII unit per kilogram of body weight will increase the plasma FVIII level by approximately 2%. The half-life is 8 to 12 hours; there- fore the interval of IV dosing can vary from 8 to 24 hours depending upon initial biodistribution and the desired FVIII level to be maintained. Bolus dose (U) = weight (kg) ¥ (% desired FVIII level) ¥ 0.5 Continuous infusion dose (U) = expected level 100% = 4 - 5 U/kg/hr (individualize dose depending on postinfusion FVIII level) When dosing factor IX products for hemophilia B disease, the ordering physician must know that Benefix, the only recombinant product available, has a 28% lower recovery in vivo than the more highly purified plasma derived FIX products, Mononine and Alpha Nine SD. There is no significant difference in half-life, approximately 24 hours, between the two products. Each FIX unit (plasma derived) per kilogram of body weight will increase the plasma FIX level by approxi- mately 1%. However, when dosing Benefix one should use the following calculations: (FIX units required) = body weight (kg) ¥ desired FIX increase (%) ¥ 1.2 U/kg (Abshire et al. 1998) The dosing and specific uses of recombinant FVIIa, Humate-P, and aPCCs will be specifically addressed in Chapter 20. Contraindications/Adverse Reactions Generally, any allergic or anaphylactic type of reaction to infusion of any of these preparations would make a second dose contraindicated. The specifics 3. Blood Components 37 Ch03.qxd 12/19/05 4:12 PM Page 37 surrounding each product will be addressed in Chapter 20. Another problem is inhibitor formation with antibodies directed against an infused factor or protein contained in the preparation. Inhibitors render the product ineffective, blocking the product’s ability to aid in hemostasis. This type of adverse reaction, technically the most severe, would make the product in question contraindicated. Further discussion of inhibitor formation and treatment can be found in Chapter 20. ALBUMIN Description Albumin is the most abundant of the plasma proteins (3500 to 5000 mg/dL) and has multiple functions. Its main purpose is to maintain plasma colloid oncotic pressure. Synthesis of albumin occurs in the liver, and there are small body stores, which undergo rapid catab- olism. Each molecule remains intact for approximately 15 to 20 days. Albumin produced specifically for trans- 38 Josephson and Hillyer TABLE 3.4 Plasma-Derived Factor Products Factor Manufacturer Virus Inactivation Purification Purity Comments Factor VIII Cryoprecipitate AHF Blood Center None Low Only used for FVIII deficiency when other factors unavailable Factor VIII Humate-P Aventis Behring Pasteurization Intermediate Licensed for vWD treatment Factor VIII Alphanate Alpha Therapeutic Solvent detergent Gel High Contains vWF (S/D), heat chromatography treated, filtered Factor VIII Koate-DVI Baxter S/D, polysorb High Stabilized with 80, heat treated human albumin Factor VIII Hemofil M Baxter S/D Immunoaffinity Ultra-high Mouse protein, trace chromatography Factor VIII Monoclate-P Aventis Behring Pasteurization Immunoaffinity Ultra-high Stabilized with chromatography human albumin Factor IX Konyne 80 Bayer Heat treated Low PCC, high content of FII, VII, IX, X Bebulin VH Immuno Heat treated Low Factor IX Proplex T Baxter Heat treated PCC, high content of FII, VII, IX, X Factor IX Alpha Nine Alpha Therapuetic S/D Immunoaffinity Contains factor IX only. Mononine Aventis Behring Non-S/D Chromatography Recovery after infusion is normal compared to recombinant FIX product (see text). Factor IX Autoplex-T Nabi Heat treated aPCC, high content FVIIa, IXa, Xa Factor IX FEIBA VH Bayer Heat treated aPCC, high content FVIIa, IXa, Xa Factor XIII Fibrogammin P Aventis Behring Pasteurization Administered every 4–6 weeks Ch03.qxd 12/19/05 4:12 PM Page 38 fusion purposes is separated from human plasma through a cold ethanol fractionation procedure. Com- mercially available human albumin preparations include a 5% solution, a 25% solution, and a plasma protein fraction 5% solution (PPF).All preparations are from pooled plasma and have a balanced physiological pH, contain 145 mEq of sodium, and contain less than 2 mEq of potassium per liter. The products contain no preservatives or coagulation factors. Indications Albumin has a wide variety of uses (Table 3.6). It is indicated after large-volume paracentesis, for nephrotic syndrome resistant to diuretics, and for volume/fluid replacement in plasmapheresis. Relative indications include adult respiratory distress syndrome (ARDS); cardiopulmonary bypass pump priming; fluid resuscita- tion in shock, sepsis, and burns; neonatal kernicterus; and enteral feeding intolerance. A further detailed dis- cussion can be found in Section IV, Chapters 13 and 17, as well as in Section VII. Ordering Albumin is an acellular product virtually devoid of blood group isohemagglutinins. Therefore, neither serologic testing nor ABO or Rh compatibility is necessary prior to administration. It is important to specify the percent solution preparation of albumin when ordering because the volume infused will vary accordingly. Dosing In children with hypoproteinemia 0.5 to 1 g/kg/dose is recommended and may be repeated one to two times in a 24-hour period. No more than 250 grams should be administered within 48 hours and the infusion should run over 2 to 4 hours. Contraindications Albumin use is contraindicated in the following situ- ations: correction of nutritional hypoalbuminemia or hypoproteinemia, nutritional deficiency requiring total parenteral nutrition, preeclampsia, and wound healing. Albumin should not be used for resuspending RBCs or simple volume expansion (for example, in surgical or burn patients). Furthermore, it should not be adminis- tered to those patients with severe anemia or cardiac failure or with a known hypersensitivity. Adverse Reactions These include hypertension due to fluid overload, hypotension due to hypersensitivity reaction, as well as fever, chills, nausea, vomiting, and rash. GAMMA-GLOBULINS Description Immune Globulin Intravenous (Human) is the FDA- approved name for IVIG. The product was first licensed 3. Blood Components 39 TABLE 3.5 Recombinant Factor Products Products Factor/Generation Manufacturer Protein Additives Comments Kogenate Factor VIII Bayer Human albumin • Half-life 8–12 hours Bioclate First Aventis Behring Human albumin • Dosing varies from continuous 4–5 U/ Helixate Aventis Behring Human albumin kg/hour to every 24 hours depending Recombinate Baxter Human albumin upon hemostatic injury Helixate FS Factor VIII Aventis Behring Human albumin • Kogenate and ReFacto formulated with Kogenate FS Second Bayer None sucrose ReFacto Genetics Institute/Wyeth None • ReFacto is B-domain deleted FVIII • Half-life and dosing same as first generation products Benefix Factor IX Genetics Institute/Wyeth None • 28% lower recovery rate then plasma- First derived FIX products, thus must dose 20% higher to achieve same level of hemostasis NovoSeven Factor VIIa NovoNordisk None • Half-life 2 hours First • Dosing for factor VIII and IX inhibitor patients—only FDA-approved indication 90–300 mg/kg for first 48 hours of bleeding episode, then every 2–6 hours based on clinical hemostasis assessment Ch03.qxd 12/19/05 4:12 PM Page 39 in the United States in 1981 and is currently the most widely used plasma product in the world. IVIG is pre- pared by fractionation of large pools of human plasma and has a half-life between 21 to 25 days, similar to native immunoglobulins. However, increased clearance of immunoglobulins has been seen in states of increased metabolism such as fever, infection, hyperthyroidism, or burns. There are numerous preparations available, each prepared in a slightly different manufacturing process. There are theoretical disadvantages and advantages linked to each licensed product. An ideally composed product should contain each IgG subclass; retain Fc receptor activity; have a physiologic half-life; demon- strate virus neutralization, opsonization, and intra- cellular killing; and possess antibacterial capsular polysaccharide antibodies. In addition, the product should be devoid of transmissible infectious agents and vasoactive substances. In reality, although each company strives for this composition, certain brands have better profiles than others regarding the treatment of different disease states. For example, Polygam S/D and Gammagard S/D, both produced by Baxter, have <3.7 mg/mL IgA content and are therefore the most suit- able IVIG product for IgA-deficient patients. IVIG’s immunomodulatory effects are not well understood. There are several postulated mechanisms of action, such as autoantibodies inhibition, increased IgG clearance, complement activation modulation, macrophage-mediated phagocytosis inhibition, cytokine suppression, superantigen neutralization, and B and T cell function modulation. The wide range of potential effects explains the vast array of on- and off-label IVIG indications. Indications There are six FDA-approved uses for IVIG, four of which are directly applicable to children (Table 3.7).The efficacy of IVIG in the following four indications has been well substantiated in controlled clinical trials (Buckley et al. 1991; Anonymous 1999; Cines and Blanchette 2002). The approved uses are idiopathic thrombocytopenic purpura (ITP), congenital (that is, severe combined immunodeficiency syndrome [SCIDS]) and acquired immunodeficiences (that is, pediatric human immunodeficiency virus [HIV]), and Kawasaki syndrome (mucocutaneous lymph node syn- drome) (Burns et al. 1998). Interestingly, greater than half of the IVIG produced yearly is used for off-label indications Table 3.8 (Nydegger et al. 2000;Anonymous 1999). More in-depth discussion of the on- and off-label uses of IVIG are covered in various chapters through- out Section IV. Ordering When ordering an IVIG product it is good to know that most hospitals will use whatever immunoglobulin preparation they have available at the time unless the physician specifies otherwise. In most situations that substitution is appropriate. However, in certain disease states such as renal insufficiency and IgA-deficiency, a specific knowledge of the product is important. Table 3.9 (modified from Knezevic-Maramica and Kruskall 2003) lists seven licensed products with some of their specifications. Dosing The dose of IVIG used is dependent upon the disease being treated—not the type of product being adminis- 40 Josephson and Hillyer TABLE 3.6 Albumin Indicated Nephrotic syndrome resistant to potent diuretics Volume/fluid replacement in plasmapheresis Possibly Indicated Adult respiratory distress syndrome Cardiopulmonary bypass pump priming Fluid resuscitation in shock/sepsis/burns Neonatal kernicterus To reduce enteral feeding intolerance Not Indicated Correction of measured hypoalbuminemia or hypoproteinemia Nutritional deficiency, total parenteral nutrition Red blood cell suspension Simple volume expansion (surgery, burns) Wound healing Investigational Cadaveric renal transplantation Cerebral ischemia Stroke Common Usages Serum albumin <20 g/dL Nephrotic syndrome, proteinuria, and hypoalbuminemia Labile pulmonary, cardiovascular status Cardiopulmonary bypass pump priming Extensive burns Plasma exchange Hypotension Liver disease, hypoalbuminemia, diuresis Protein-losing enteropathy, hypoalbuminemia Resuscitation Premature infant undergoing major surgery Ch03.qxd 12/19/05 4:12 PM Page 40 [...]... 22 % 23 % 1% 6% 15% 0% 0% 0% 2% 7% 16% 2% 13% 33% 2% 5% 19% 0.4% 0.4% 0.7% African-Americans 21 % 6% African-American M+N-S+sM+N-S+s+ M+N-S-s+ M+N+S+sM+N+S+s+ M+N+S-s+ M-N+S+sM-N+S+s+ M-N+S-s+ M+N-S-sM+N+S-sM-N+S-s- Caucasians P1-negative Phenotypes TABLE 4.13 Prevalence of MNS Antigen-Negative Phenotypes Prevalence Phenotypes Caucasians African-Americans M-negative N-negative S-negative s-negative U-negative... Mild-severe Mild Mild Mild-severe Rare Mild-severe Mild-severe Mild-moderate Mild-moderate Mild-moderate Mild-moderate Mild-severe Mild Mild-moderate None-mild None-mild None None-severe None-severe Mild-severe None None None-mild Mild +DAT/ No HDN None Mild-severe Mild None 40% 11% 85% 68% 29 % 80% 98% 9% 99.8% 2% >99% 99% 66% 83% 77% 74% 78% 70% 52% 89% 100% 22 % 72% 8% >99% 67% 27 % 20 % 92% 27 % 22 %... Population Transfusion Reactions Mild-severe Mild-severe Mild-severe Mild-severe Mild-moderate Mild-severe Mild-moderate Mild-severe Mild-moderate Mild-moderate None-moderate None-moderate Mild-moderate Mild-severe Mild-severe None-severe None-severe None None None-moderate None-mild Mild-severe Few None None Mild-moderate Rare Rare None-moderate None-moderate Rare HDN* Caucasians None-moderate None-moderate... Populations Lu(a+b-) Lu(a-b+) Lu(a+b+) Lu(a-b-) 0 .2% 92. 4% 7.4% Rare TABLE 4.16 Prevalence Phenotypes Le(a+b-) Le(a-b+) Le(a-b-) Le(a+b+) Caucasians African-Americans 22 % 72% 6% Rare 23 % 55% 22 % Rare Prevalence of Lutheran Antigen-Negative Phenotypes Prevalence Phenotypes Caucasians African-Americans Lua-negative Lub-negative 92% . Mild-severe 85% 92% C Rh X Mild-severe Mild 68% 27 % E Rh X X Mild-moderate Mild 29 % 22 % c Rh X Mild-severe Mild-severe 80% 96% e Rh X Mild-moderate Rare 98% 98% K Kell X X Mild-severe Mild-severe. Caucasians African-Americans Asians Jk(a+b-) 26 .3% 51.1% 23 .2% Jk(a-b+) 23 .4% 8.1% 26 .8% Jk(a+b+) 50.3% 40.8% 49.1% Jk(a-b-) Rare Rare 0.9% TABLE 4.11 Prevalence of Kidd Antigen-Negative Phenotypes Prevalence Phenotypes. rarely bind com- plement. Anti-K is strongly immunogenic and is fre- quently found in the serum of transfused K-negative patients. Anti-k, -Kp a , -Kp b , -Js a , and -Js b are less com- monly observed