Blood Component Therapy

Transcription

1 Blood Component Therapy Dr Anupam Chhabra Incharge-Transfusion Medicine Pushpanjali Crosslay Hopital NCR-Delhi Introduction Blood a blood components are considered drugs because of their use in treating diseases. As with drugs, adverse effects may occur, necessitating careful consideration of therapy. The transfusion of blood cells is also transplantation, in that the cells mu survive a function after transfusion in order to have a therapeutic effect. The transfusion of red blood cells (RBSs) is the be tolerated form of transplantation, but it may cause rejection. The rejection of platelets shown as refractoriness to the platelet transfusion is relatively common in multiple transfused patients. Fresh Frozen Plasma can be used to replace all coagulation factors, so it especially useful to treat multiple coagulation deficiencies occurring in patients with liver failure, DIC, vitamin K etc. Cryoprecipitate contains factor VIII, fibrinogen, von Wille bra factor (vwf), a factor XIII, thus this product can be used to correct deficiency of these coagulation factors. Each patient mu be evaluated iividually to determine the proper transfusion therapy, taking care to avoid inappropriate over- or uertransfusion. Transfusion decisions should be based on clinical assessment anot on laboratory values alone. Red blood cells The decision to transfuse red blood cells should be based on clinical assessment of the patient a their response to any previous transfusion as well as the hemoglobin level. The function of a RBC transfusion is to exte oxygen delivery to tissues. Hemoglobin levels during Dr Anupam Chhabra active bleeding are imprecise measures of tissue oxygenation. Adequate or inadequate fluid resuscitation can significantly alter the measured hemoglobin concentration. In addition, a number of factors mu be considered besides the blood hemoglobin level such as oxygenation in the lungs, blood flow, hemoglobin, oxygen affinity a tissue demas for oxygen. Consequently, the adequacy of oxygen delivery mu be assessed in iividual patients. Dosage: A dose of one unit of compatible Red Blood Cells will increase the hemoglobin level in an average sized adult who is not bleeding or hemolysing by approximately 1 g/dl or Hct by 3%. In neonates, a dose of ml/kg isgenerally given, packed red cells with a hematocrit of approximately 60% will increase the hemoglobin by about 3 g/dl. Response: Unless the recipient is bleeding or hemolysing, a provided the transfused red cells are compatible, the po-transfusion hemoglobin can be accurately predicted from the patient s eimated blood volume, baseline red cell volume a transfusion volume. Transfused red cells have a half-life of approximately 30 days in the absence of other processes that would result in red cell loss or premature removal. Iications: Red blood cells are iicated for patients with asymptomatic deficiency of oxygen-carrying capacity or tissue hypoxia due to an inadequate circulating red cell mass. They are also iicated for exchange transfusion (eg, for hemolytic disease of the newborn)

2 a red cell exchange (eg, for acute che syrome in sickle cell disease). 1. Transfusion is rarely iicated when the hemoglobin level is above 10 g/dl a is almo always iicated inpatients when the hemoglobin level is below 6 g/dl; 2. The determination of transfusion in patients whose hemoglobin level is 6-10 g/dl should be based on any ongoing iication of organ ischemia, the rate a magnitude of any potential or actual bleeding, the patient s intravascular volume atus a risk of complications due to inadequate oxygenation. 3. Transfusion for patients on cardiopulmonary bypass with hemoglobin level 6.0 g/dl is iicated. 4. Hemoglobin level 7.0 g/dl in patients >65 years a patients with chronic cardiovascular or respiratory diseases is iicated. 5. For able patients with hemoglobin level between 7 a 10 g/dl, the benefit of transfusion is unclear. 6. Transfusion is recommeed for patients with acute blood loss more than 1,500 ml or 30% of blood volume. 7. Evidence of rapid blood loss without immediate control blood transfusion is iicated. Table 1. In Neonates a Critically Ill Children Maintain HCT between Clinical Status 40-45% Severe cardiopulmonary disease (e.g., mechanical ventilation >0.35 FiO2) 30-35% Moderate cardiopulmonary disease (e.g. less intensive assied ventilation such as nasal CPAP or supplemental oxygen) 30-35% Major surgery 20-30% Stable anemia, especially if unexplained breathing disorder or unexplained poor growth Controversial iications include Leg ulcers, Pregnancy, Silent cerebral infarct a/or neurocognitive damage. Inappropriate Iications a Contraiications: Chronic, eady-ate (asymptomatic anemia) Uncomplicated pain episodes Infection Minor surgery that does not require general Table 2. Adminiration of Packed Red Blood Cells Recipient (Patient) A B O AB A 1 2 B 1 2 Rh Rh Positive Negative O 1 AB 2 1 Rh 1 2 Positive Rh 1 Negative anehesia Aseptic necrosis of the hip or shoulder (unless iicated for surgery) Uncomplicated pregnancy Platelets Platelets are also referred to as whole blood derived platelets, raom donor platelets (RDP), raom platelet concentrates. Platelet pheresis is also referred to as single donor platelets, or SDPs. RDP are derived from Whole Blood a should contain 5.5 x 10^10 platelets per bag in approximately 50-0 ml of plasma. SDP is obtained using automated cell separators a should contain 3.0 x 10^11 plateletsper bag in >200 ml of plasma. Dosage: To help prevent or treat bleeding, transfuse as needed to maintain target platelet count. Prophylactic platelet transfusion in surgical patients: i. Rarely iicated when the platelet count is >100 x 10 /l ii. Usually iicated when the count is <50 x 10 /l iii. With intermediate platelet counts ( x 10 /l) - based on the risk of bleeding Surgical a obetric patients with micro vascular bleeding: I. Usually require transfusion if the platelet count is <50 x 10 /l

3 Table 3: Current Prophylactic Platelet Transfusion Triggers Patient Category ii. Rarely require therapy if it is >100 x 10 /l iii. With intermediate platelet counts ( x 10 /l)- based on the patient's risk for more significant bleeding iv. Vaginal deliveries or operative procedures ordinarily associated with insignificant blood loss may be uertaken in patients with platelet counts less than 50 x 10 /l v. Platelet transfusion may be iicated despite an apparently adequate platelet count if there is known platelet dysfunction a micro vascular bleeding. vi. When the platelet count cannot be done in a timely fashion in the presence of coagulopathy, platelets may be given when thrombocytopenia is suspected. Transfusion of Platelets SDPs a RDPs should be ABO-identical with the recipient when possible. Table 4. Adminiration of Platelets Platelet Count All Patient or Stable patient 5000/µl Patient with fever or recent hemorrhage (now opped) Patient with Coagulopathy, on heparin, or with anatomic lesion likely to bleed Patients at risk for transfusion-associated graft-versus ho disease (TA-GVHD) should receive gamma irradiated platelets. The dose of platelets is determined by the pretransfusion platelet count, blood volume a the presence of additional risk factors. A dose of one raom donor unit per 10 kg body weight may be used as a guide. Response: Po-transfusion platelet counts should be obtained between minutes after infusion to asses transfusion recovery. Generally, expect an adult platelet count increment of approximately 7-10,000/mm3 for each RDP given, or 30-60,000/ mm3 for each SDP given. In neonates a infants, a dose of 5-10 ml/kg of platelets (RDP or SDP) should result in a ,000/mm3 increment. Transfusion Refractoriness: a) To assess the platelet survival a poinfusioncounts at 24 hours should be performed (in non-immune factors such as sepsis, splenomegaly, DIC, etc.) b) Alloimmune refractoriness may develop when at lea two consecutive poor platelet increments at minutes after transfusion. Contraiications: 1. Thrombotic thrombocytopenic purpura (TTP), Idiopathic thrombocytopenic purpura (ITP), Hepariniuced thrombocytopenia, unless life threatening hemorrhage exis. 2. There is no role for prophylactic platelet transfusion in routine primary open heart surgery unless there is: Recipient's (Patient's) ABO STATUS 1ST CHOICE 2ND CHOICE 3RD CHOICE 4TH CHOICE AB AB A* B* O* A A AB B* O* B B AB A* O* O O A B AB Recipient's Rh D Status Rh positive Rh negative Rh positive Rh negative Rh positive 1 Choice 2 Choice 1 Choice 2 Choice Rh negative 2 Choice 1 Choice 2 Choice 1 Choice *In non-availability of group specific platelet concentrate, non-group specific platelet concentrate can be transfused after consultation.

4 i. Micro vascular bleeding a platelet count 50,000/µl ii. Microvascular bleeding (eg, po-operative che tube drainage greater than 500 ml within 6 hours) a non-diagnoic coagulation abnormality. 3. Surgery or invasive procedure where platelet counts is more than 50,000/µl, prophylactic platelet transfusion is not iicated. Fresh frozen plasma Plasma consis of the non-cellular portion of blood that is separated a frozen after donation. It may be prepared from whole blood or collected by apheresis.it contains all coagulation factors. Dosage: The amount of FFP needed depes on the patient s clotting factor levels, the levels needed to attain a therapeutic result, whether or not the patient is bleeding, a the patient s blood volume. If possible, coagulation tes (ie, PT or INR a aptt) should be performed before the adminiration of FFP in a bleeding patient. Iications: Fresh Frozen Plasma is iicated for use in patients with the following coitions: 1. Active bleeding due to deficiency of multiple coagulation factors, or risk of bleeding due to deficiency of multiple coagulation factors. 2. Severe bleeding due to warfarin therapy, or urgent reversal of warfarin effect 3. Massive transfusion with coagulopathy a bleeding. Table 5: Adminiration of Fresh Frozen Plasma Recipient (Patient) A B O AB A 1 2 B 1 2 O 2 rd 3 1 th 4 AB 1 Note: Rh(D) positive plasma should not be given to Rh(D) negative women in the reproductive age group. 4. Bleeding or prophylaxis of bleeding for a known single coagulation factor deficiency for which no concentrate is available. 5. Thrombotic thrombocytopenic purpura. 6. Rare specific plasma protein deficiencies, such as C1- inhibitor. Contraiications: 1. Increasing blood volume or albumin concentration 2. Coagulopathy that can be corrected with adminiration of Vitamin K. 3. Normalizing abnormal coagulation screen results, in the absence of bleeding. 4. Hypovolaemia, plasma exchange procedures or treatment of immunodeficiency ates. Cryoprecipitate Cryoprecipitate AHF is prepared by thawing FFP a a recovering the precipitate. It contains factor VIII, fibrinogen, vonwillebra factor (vwf), a factor XIII. Dosage: The number of cryoprecipitate units can be eimated byusing the following calculation 1. Weight (Kg) x 70mL/Kg = blood volume (ml) 2. Blood volume (ml) x (1.0-hematocrit) = plasma volume(ml) 3. Fibrinogen required (mg) = (desired fibrinogen level (mg/dl) - initial fibrinogen level (mg/dl)) multiplied by (plasma volume (ml) / 100). 4. Bags of cryoprecpitate required = mg fibrinogen required/ 250 mg fibrinogen per bag of cryo. The frequency of dosing depes on the half-life a recovery of the coagulation factor that is being replaced (check factor levels). As a thumb rule - one cryoprecipitate unit per 7-10 kg of body weight can be transfused. Iications: Patients with fibrinogen deficiency where there is clinical bleeding, an invasive procedure, trauma or disseminated intravascular coagulation. Adminiration of Cryoprecipitate Cryoprecipitate may not be ABO identical however ABO compatible cryoprecipitate is preferred. The compatibility teing is not necessary, Rh type need not be considered when using this component.

5 Response: Pretransfusion a po-transfusion coagulation factor levels should be determined to assess the adequacy of the cryoprecipitate dose. Contraiications: This component is not generally considered appropriate in the treatment of i. hemophilia ii. von Will bra s disease, or deficiencies of factor XIII or fibronectin, unless alternative therapies are unavailable. Conclusions: Patients who require blood or blood products, whether in life-threatening acute situations or as a supportive therapy in chronic hematological disorders, mu receive the required component only. Transfusion of packed red blood cells should be used for situations in which clear physiological iicators for transfusion are present. Depeing upon the coition a disease of the patient prophylactic platelet transfusion trigger can be as low as. Before adminiration of FFP in a bleeding patient coagulation profile should be obtained. Fibrinogen concentration should be obtained before the adminiration of cryoprecipitate in a bleeding patient. References 1. Staards for Blood Banks/Bank Centers a Transfusion Services, NABH. 2. Transfusion Medicine Technical Manual Seco edition; Directorate General of Health Services, Miniry of health & Family Welfare, Govt. of Iia, New Delhi. 3. Practice Guidelines for Blood Transfusion, seco edition, American Red Cross. 4. Practice Guidelines for Perioperative Blood Transfusion a Adjuvant Therapies; 2006 American Society of Anehesiologis, Inc. Lippincott Williams & Wilkins, Inc.