(pt 2) exam #4 - immunohematology (cls 544)

component preparation and transfusion therapy

purpose of anticoagulant preservative solutions

• Prevent activation of clotting factors

• Citrate-based, bind calcium and blocks the coagulation cascade

• Maintain blood in liquid transfusion

• Extends the shelf-life of blood components

***ACD, CPD, CP2D have a shelf life of 21 days

***CPDA-1 shelf life 35 days

production of blood components from whole blood

• Whole blood collected from donor into plastic collection bag containing anticoagulant preservative

  • Satellite bags are storage containers for blood components prepared from donation

    • e.g. plasma, platelets

• The closed system ensures no foreign contaminants from the outside environment can enter system

(component preparation) whole blood

• Comprised of all plasma and cellular components of blood

• Not typically used for transfusion

• Separating whole blood into components allows multiple patients to benefit from single blood donation

  • WB volume: ~450-500 mL

  • Hematocrit ~38%

(component preparation) packed RBCs

• Prepared by centrifuging whole blood

• During centrifugation, the RBCs concentrate at the bottom of the container, followed by white blood cells and platelets

• Top portion of centrifuged collection bag contains liquid plasma portion of whole blood

(component preparation) processing of packed RBCs

• After centrifugation, blood unit plasma expressor

• RBCs and plasma bags separated using tubing sealer

• Packed RBCs component:

  • If additive solutions (AS) used, Hct ~55 to 65%

  • If AS not used, Hct 65-80%

  • 50 to 80 grams of hemoglobin, final volume ~160 to 275 mL

  • ASI, AS3, AS5, AS7--42 days of storage

(component preparation) plasma 

• Stored frozen to preserve activity of labile plasma proteins

  • e.g. Factors V and VIII

• Frozen plasma thawed prior to transfusion

• Stored in thawed state for short periods of time

• 1 unit of each coagulation factor in every 1 mL of FFP

• WB-derived plasma volume range from 200-375 mL

(component prep) solvent/detergent & recovered plasma

• Solvent/detergent plasma

  • Used to inactivate lipid-enveloped viruses such as HIV, HBV, HCV, and CMV

• recovered plasma

  • Proteins separated out for patient use

    • e.g. albumin, specific coagulation factors

(component preparation) cryoprecipitated antihemophilic factor (AHF)

• Frozen FFP thawed slowly at 1-6 C; insoluble proteins precipitate out of the plasma in the cold

  • Fibrinogen, Factor VIII, Factor XIII, von Willebrand factor (vWF) and fibronectin

• 15 mL of residual plasma is left with the insoluble proteins

• Each unit must contain a minimum of 80 IU of Factor VIII and 150 mg of fibrinogen

• remaining plasma (minus the cryo) is called cryoprecipitate reduced plasma

 

(component preparation) platelets (PRP method)

• Donations maintained at RT during all stages of collection, storage, and production

• Platelet-rich plasma (PRP) method

  • Produces a single platelet component from single WB donation, random-donor platelets (RDPs)

  • Contains a minimum of 5.5 x 10¹⁰ platelets

  • Total volume 40-70 mL

  • Residual RBCs cannot exceed 1.0 x 10⁹ RBCs per component

  • One therapeutic dose for adult equivalent to 4-6 PRP platelets, each prepared from one WB donation

buffy coat (B/C) method for platelet preparation 

• produces pool of plts from 4-6 whole blood donations

  • Whole blood subjected to hard spin

  • Second stage starts with pooling buffy coats with one plasma component or bag of platelet additive solution

  • Most common in Europe and Canada

  • One pooled B/C platelet is generally considered a normal adult dose

(component preparation) granulocytes

• White blood cells are not often prepared from whole blood

• Apheresis collection technique results in higher number of granulocytes per collection

  • Buffy coat isolated by using hydroxyethyl starch (HES) to precipitate out the WBCs

  • 1.0 x 10^10 granulocytes

  • Shelf life 24 h--transfused ASAP

  • Stored at room temperature

blood component labeling

• ISBT 128 Labeling includes: 

  • Donation ID number; blood group of donor

  • Product code and description

  • Expiration date & Special testing done

• Label provides all information necessary to handle product appropriately

  • Circular of information

(storage of blood components) adverse effects of RBCs storage

• Blood removed from body undergoes changes and can influence how components function

• Apoptosis = programmed cell death

• Hemolysis is the most obvious impact of storage on RBCs

  • Freed hemoglobin is released into the storage fluid

• Metabolic activity and oxygen release reduce levels of ATP and 2,3-DPG

• Many of these changes are reversible after transfusion

(storage of blood components) RBC viability

• Loss of RBC viability has been correlated with the lesions of storage

• Associated with various biochemical changes within the pRBC unit

  • Glucose, ATP, pH, and 2,3-DPG, # of viable cells are all decreased

  • Lactic acid, plasma K+, and plasma Hgb are all increased

(storage of blood components) adverse effects of storage on platelets

• Very fragile and sensitive

• Adversely affected by temperature and forces applied during centrifugation

• High levels of metabolic activity during storage

• Prolonged storage eventually leads to cell death

platelet storage lesion (see pic)

• Quality control measures

  • Platelet concentrations

    • Platelet concentrate volume

    • Platelet count

    • pH of the platelet unit

    • Residual leukocyte count (if leukoreduced)

  • Visual inspection--assess platelets swirl (observe for any platelet aggregates)

    • Loss of swirl indicates loss of membrane integrity during storage

adverse effects of storage (general)

• Cellular blood components most susceptible to storage lesion

• Transfused cells must remain intact and metabolically active

• Plastics used in collection and storage containers affect cell function

• Anticoagulant preservative solutions play significant role in reducing storage lesion

• Storage conditions

  • Temperature and length of time of storage

  • Colder storage temperature = longer component may be stored

• Providing continuous agitation to platelet components important!

• Use of additive solutions prolongs storage time for cellular components

  • e.g. red blood cells

(storage of blood components) adverse effects on granulocytes, plasma, and bacteria considerations 

• Granulocytes

  • Fragile and deteriorate quickly after removal from body

  • Rapid deterioration = release of cytokines and intracellular enzymes = cell death of RBCs and platelets

• Plasma protein

  • Most very stable; factors V and VIII breakdown when plasma is stored in the refrigerator or room temp

• Bacteria

  • Risk for minute numbers of bacteria may enter the closed system

  • Bacterial metabolism can accelerate RBC, WBC, and platelet destruction

  • Can cause severe reactions in transfused patients

storage conditions for RBC products

• whole blood/pRBC + ACD/CPD/CP2D = 1-6 C

  • expires 21 days from collection

• whole blood/pRBC + CPDA-1 = 1-6 C

  • expires 35 days from collection

storage conditions for platelet products & granulocytes

• both store at 20-24 C

  • platelets need continuous gentle agitation

• expiration time:

  • up to 7 days for platelets

  • 24 hrs for granulocytes

storage conditions for plasma products

• FFP: store at < -18 C for up to 12 months

  • same for cryoprecipitated AHF & reduced cryoprecipitate

• FFP after thawing: store at 1-6 C for up to 24 hours

• thawed plasma: store at 1-6 C; expires 5 days from thawing

• liquid plasma: store at 1-6 C; espires 5 days after expiration of WB

• thawed cryoprecipitated AHF: 20-24 C for up to 6 hours

• reduced plasma cryoprecipitate thawed: 1-6 C; expires 5 days from thawing

transportation of blood components

• Blood collected in donor clinic must be transported to production laboratory for component prep

• Blood separated into components, stored, and labeled upon review of serological/viral marker test results

• Must have the ability to maintain temperature range for components being shipped (1 C - 10 C)

  • Phase-change materials are a compound that shift between solid and liquid state at specific temperatures

(blood component modifications) leukoreduction

Removes WBCs from whole blood or blood components & helps to prevent formation of antibodies to HLA antigens because WBCs carry HLA antigens

• Reduces risk of adverse reactions in transfused patients & decreaes viral load of CMV, HTLV, & EBV

  • e.g., HLA, TRALI, organ rejection (TA-GVHD), plt refractoriness 

• Leukoreduction filter may be used

  • Leukocyte reduction filters remove 99% WBCs (<5×10⁶/unit)

• Acceptable number of remaining leukocytes = 5 x 10^6 per component

(blood component modifications) pathogen inactivation

• Process that inactivates viruses and bacteria in prepared blood components

  • Solvent and detergent treatment: HIV, HBV, HCV, HTLV, EBV, CMV, HHV-6, HHV-8

  • Plasma treated using methylene blue, psoralen (platelets), or riboflavin

(blood component modifications) aliquoting & pooling

• Aliquoting

  • To prepare product for low-volume transfusion, usually neonatal or pediatric patients

  • Can be done in a closed or open system

• Pooling

  • Reduce number of bags accessed at time of transfusion

  • Commonly done with PRP platelets or cryo to create a single dose

(blood component modifications) volume reduction

• Remove plasma or additive solution from components

• Done via centrifugation

• Reduces risk for circulatory overload and adverse reactions related to transfusion of certain plasma proteins

(blood component modifications) irradiation & washing & rejuvenation

• Irradiation

  • Exposing blood components to gamma or x-ray radiation inactivates T lymphocytes

  • No adverse effect on platelet or red blood cell function

  • Increased potassium leakage into the storage fluid

• Washing

  • removes plasma proteins that can cause severe reactions in certain patient populations

• Rejuvenation

  • Rejuvenates and restores RBCs up to 3 days after expiration with FDA-approved solution

(blood component modifications) freezing, thawing, deglycerolizing RBCs

• Freeze and store RBCs with rare phenotypes for long period of time (below -65 C, 10 years)

• RBCs normally undergo cell lysis when frozen, then thawed

• Glycerol (high-40%, low-20%) limits formation of ice crystals within RBCs, reducing damage to cell membrane

• Deglycerolization

  • Washing thawed component with successive concentration changes of sterile saline solution, starting with hypertonic saline, 1-6 C, open system for 24 hours; closed-14 days

RBCs that are not properly leukoreduced can produce what adverse reactions?

• Febrile, non-hemolytic reaction

• Reaction to cytokines

• Alloimmunization to HLA or granulocyte antigens

• Transmission of CMV

plasma fractionation

• Plasma not used for transfusion can be shipped to large manufacturing facilities

  • Solvent/detergent treatment

  • Heat or nanofiltration process

• Facilities separate out specific proteins and package them to meet specific patient needs

  • Albumin (5% or 25%)

  • Immune globulins (e.g. RhIG, IVIG)

  • Coagulation proteins

    • FVIII, FIX, fibrinogen, anti-thrombin III, protein C

recombinant protein production

• Produced by inserting genetic information that codes for specific human protein into DNA of plant or animal cells

  • Production does not rely on availability of donor plasma

  • Manufacturers use methods that use no human or animal derived proteins during production

  • Completely within manufacturer's control

  • Factor VII and Factor IX in use in recombinant form rather than plasma derived

blood banks without collection facilities

• Blood banks that depend on an outside source for their blood supplies usually receive their products in component form

• Platelet concentrates and cryoprecipitate may be received as individual units but are more easily administered if pooled before infusion

• Individual units of platelets outdate in 5 days

• Pooled platelets in open system are good for 4 hours

  • Proper timing for utilization is critical

• Sterile connecting devices (STCDs) have also become commonplace in some blood banks

blood bank equipment for storage / processing of blood products

• Refrigerators

  • Packed RBCs and whole blood—1-6 C

  • Storage requirement for transportation of RBC: 1-10 C

• Freezers

  • Maintained at -18 C or lower for FFP, FFP24, and cryoprecipitate

  • Maintained at -65 C or lower for frozen RBCs (40% glycerol)

• Platelet Rotators/Flatbed Agitators

  • Provide constant gentle agitation @ RT for storage of apheresis and random donor platelets

    • 20-24 C

• Automated Cell Washer

  • Used to prepare washed RBCs or to deglycerolize frozen RBCs

(blood bank instruments) irradiator

used to render donor T lymphocytes nonfunctional in whole blood, red blood cells, platelets, and granulocytes prior to transfusion

• Prevents development of Transfusion Associated Graft-Versus Host Disease (TA-GVHD) by gamma irradiation of cellular blood products

• Storage-life of red blood cells and whole blood reduced to 28 days or original outdate, whichever is sooner

• Immunocompromised patients, fetus and neonates, transplant patients, or patients receiving transfusion from a relative (directed donation) are at increased risk of TA-GVHD

goals of tranfusion therapy

• Common goals

  • Increase oxygen-carrying capacity

  • Restore hemostasis

• Laboratory testing

  • CBC is the first laboratory test performed to assess need for transfusion

  • Common coagulation screening tests

    • PT, aPTT, INR, and fibrinogen

transfusion therapy (general)

• Blood components are deemed as "drugs" by the FDA

• RBCs are the best tolerated blood product for transfusion

• Rejection of platelet components are relatively common for patients who have received multiple platelet transfusions

• Appropriate transfusion therapy requires proper selection of blood products for treatment and optimization of blood product inventory

• decision to transfuse blood into a patient is not made lightly

  • Severely anemic patients may require an infusion of pRBCs to increase O2-carrying capacity of the blood

  • Platelets given to patients with decreased platelet quantity or function

  • Plasma given to patients who require an infusion of coag factors

transfusion triggers for RBCs + expected response

• trigger: hgb < 7 g/dL; higher if there are underlying cardiac/pulmonary disease

• common adult dose: 1 unit

  • expected response: hgb increases by 1 g/dL per dose 

transfusion triggers for FFP + expected response

• trigger: aPTT/PTT increases greater than 1.5 upper limit or INR > 1.5

• common adult dose: 2 whole blood derived units/1 apheresis unit

  • expected response: coag factors increase by 25%

transfusion triggers for platelets + expected response

• trigger: platelet count <10 × 10³/uL

• common adult dose: 1 apheresis unit or 4-6 pooled whole blood derived units

  • expected response: increase of 30-50 × 10³/uL 1 hr post transfusion

transfusion triggers for cryoprecipitate + expected response

• trigger: fibrinogen <100 mg/dL

• common adult dose: 10 units or 1 unit/10kg body weight

  • expected response: 14 units = increase fib by 50 mg/dL 

transfusion triggers for granulocytes + expected response

• trigger: documented sepsis unresponsive to antimicrobial therapy

• common adult dose: 1 unit

  • expected response: no demonstrable rise in neutrophil count 

(transfusion therapy) categories of blood products

primary function of the blood bank is to supply the safest and most suitable blood and blood products to patients as quickly as possible

• Cellular components: whole blood, red blood cells (packed RBCs), platelets, and granulocytes

• Plasma components

  • FFP, PF24, and thawed plasma

  • Cryoprecipitate

  • Platelet products

• Hematopoietic Progenitor Cell (HPC) Products

  • Bone marrow, peripheral blood stem cells (PBSC), and cord blood

• Plasma Fractionation Products

  • Albumin, immune globulins, and coagulation factor concentrates

(transfusion therapy) infusion rate

• All blood components should be infused in LESS THAN 4 HOURS

  • Minimal risk of bacterial contamination

  • Refrigeration inhibits bacterial growth

  • Infusion rate for each patient document

  • First 10-15 min: infused slowly, vital signs

(transfusion therapy) infusion sets and filters

• Set used dependent of the time limit or maximum number of units being infused

• Standard set manufactured with flexible plastic tubing and an inline blood filter

  • Pore size: 150-260 um

    • Traps large cellular debris

(infusion sets and filters) microaggregate & leukocyte reduction filters

• Microaggregate filters for RBC transfusions

  • Pore size: 20-40 um

  • Traps degenerating platelets, WBC fragments, and small strands of fibrin

  • Pore size slows down infusion rate

• Leukocyte Reduction Filters

  • Reduce the number of WBCs in RBC (or PLT) components to less than 5 × 10⁶ WBCs/unit

  • Filters are not interchangeable between blood components

  • Can occur pre-storage while components are being prepared or before transfusion at the bedside

(infusion considerations; transfusion therapy) needles, rapid infusers, blood warmers

• Needles

  • Small bore sizes can cause hemolysis during rapid infusion of RBCs

  • 18 gauge or larger needles used for transfusion

  • Smaller needles (23 gauge) used for pediatric patients

  • Use slow infusion rate for smaller needles and large bore needles for rapid infusion of RBCs

• Rapid Infusers

  • Resemble pressure cuffs that surround entire bag of blood

  • Massive rapid infusion or infusion into central venous catheter presents a higher risk of hypothermia in recipients

  • Hypothermia can cause arrhythmia which can be fatal

• Blood Warmers: prevent hypothermia and patients with cold agglutinin disease

 

(transfusion therapy) infusion pumps and infusion solutions

• Infusion pumps

  • Mechanical pumps used to regulate blood flow into patients

  • Often used in neonates--volume shifts has a drastic impact

• Infusion solutions

  • Normal saline of 0.9% sodium chloride (USP) may be added to most blood components to increase flow rate

  • Safe to add RBC units

    • ABO-compatible plasma, 5% albumin, and Plasma-Lyte

  • Medications, intravenous solutions, Ringer's lactate solution should not be added to blood components during transfusion

  • Some solutions not compatible with fractionated products

(transfusion therapy) whole blood 

• Comprised of RBCs, platelets, and plasma

• Originally used for volume replacement (plasma)

• Improve oxygen-carrying capacity (RBCs)

• Volume replacement treated with crystalloid solutions or colloid solutions

• Component therapy replaced use of whole blood

• If whole blood used, must be ABO identical and crossmatched

  • Typically encountered with presurgical autologous donation

 

(transfusion therapy) RBC components

referred to as "packed cells" or "packed red blood cells"

• Commonly used to treat anemia

• Whole blood and pRBCs improve oxygen transport

• Transfusion Triggers

  • Hemoglobin falls between 7–10 g/dL

  • Decision to transfuse should not be based only on laboratory findings

effects of transfusing packed RBCs on hemoglobin levels

• A unit of packed RBCs is highly concentrated with RBCs

• For each unit of packed RBCs that is transfused into a patient (70 kg ro 154 lb) who is NOT actively bleeding, the patient's hemoglobin level can be expected to increase by 1 g/dL

• 1 mL of RBCs = 1 mg of iron

 

effects of transfusing packed RBCs on hematocrit levels

• estimated that one unit of packed RBCs has a hematocrit level of approx 55-65%

• For every unit of packed RBCs, the hematocrit can be expected to increase 3% in a patient (70-kg or 154 lbs) who is NOT actively bleeding

(transfusion therapy) special considerations for RBC components

• Directed Donation

  • Blood from a specific donor drawn and set aside for a specific recipient

  • blood donation from a first-degree family member? → product must be irradiated for prevention of TA-GVHD

    • Family members more likely to share the same HLA haplotype

  • donated units are screened for infectious diseases and processed into packed RBC units

• Community Directed Donations

  • Donor programs aim to treat patients diagnosed with hemoglobinopathies

    • e.g. sickle cell anemia (C, E, K matched), thalassemia

  • Benefits:

    • Decreased risk of alloimmunization, increased donor retention

(transfusion therapy) granulocytes

• WBCs collected by apheresis and used to treat neutropenic patients with bacterial and/or fungal sepsis

  • These patients are typically resistant to antimicrobial therapy

• Used as an interim therapy for patients expected to recover neutrophil production (1 × 10¹⁰ granulocytes)

• Granulocyte units should always be irradiated to prevent TA-GVHD

• Do NOT use microaggregate or leukocyte reduction filters

• Both donor and recipient should be Rh and human leukocyte antigen (HLA) compatible

• Crossmatch required when more than 2 mL of RBCs are present in the unit

(transfusion treatment of coagulopathies) FFP & transfusable plasma components

• Fresh frozen plasma (FFP)

  • Indicated for patients with multiple coagulation deficiencies that occur in liver failure, DIC, vit K deficiency, warfarin overdose, massive transfusion and multiple-factor deficiencies

• Transfusable Plasma Components

  • Cryoprecipitate-reduced plasma indicated for use for treating patients with thrombotic thrombocytopenic purpura (TTP), provides ADAMTS 13, and other coagulation factors

(transfusion treatment of coagulopathies) platelet products & cryoprecipitate

• Platelet Products

  • Indicated for patients with thrombocytopenia

  • Prophylactic treatment for patients with platelet counts under 5,000 to 10,000/μL

• Cryoprecipitate

  • Primarily used for fibrinogen replacement

(transfusion therapy) determining FFP effects 

• If separated from a whole blood unit, then the plasma is frozen or centrifuged for the purpose of removing platelets into a separate unit

  • Units are frozen w/in 8 hrs of collection to preserve all coag factors (FFP)

  • Units frozen after 8 hours BUT within 24 hours = PF24

• Fresh-frozen units thawed in the following:

  • 37°C water bath / FDA-approved microwave

• Considerations for plasma

  • 1 unit of plasma increases clotting factors by 10%

  • 2 units usually sufficient to increase clotting factor activity by 15% to 20% in a pt with diminished clotting capacity

(transfusion therapy) platelet components

• May be manufactured from WB or apheresis collection

• Platelet transfusion indicated in the following conditions:

  • Decreased platelet production

  • Increased platelet destruction

  • Platelet dysfunction

• Medications (e.g., aspirin) can alter or interfere with platelet function

• Platelet Refractoriness – recipients no longer exhibit the expected increase in platelet numbers after infusion of a platelet product

  • Commonly caused by alloimmunization directed towards HLA or platelet antigens

effects of transfusing WB-derived platelet concentrate

• will increase the platelet count by 5,000-10,000/uL in an adult patient

  • Considered a prophylactic dosage to prevent spontaneous bleeding (contains a minimum of 5.5 x 10¹⁰ platelets)

  • A platelet count of 50,000/μL deemed sufficient for most surgeries

  • Transfusion of whole blood-derived platelets will increase the platelet count by 50,000/μL in pediatric patients

how much platelet concentrate is needed to prevent spontaneous bleeding?

• Pool of 4-6 platelet concentrates (random donor platelets) OR a single donor apheresis unit (contains min 3.0 x 10¹¹ platelets) is sufficient to prevent spontaneous bleeding in a normal sized adult

  • 1 single donor apheresis unit = 4-6 random donor platelet concentrates; therefore, it should increase the platelet count by 20,000 – 60,000/μL in an adult patient (approximately 70 kg)

transfusion considerations for platelet products

• In the absence of platelet destruction or consumption, platelet transfusions may occur every 3 to 5 days

• Daily administration of platelets may be necessary if platelet destruction or consumption is observed in a patient

• In the presence of platelet destruction or consumption, the platelet count may not improve

(transfusion therapy) cryo, fibrin glue, platelet gel

• Cryoprecipitate

  • Manufactured from FFP—has fibrinogen, factor VIII, factor XIII, VWF, and fibronectin

  • Used to treat hemophilia A and source of fibrinogen (<100 mg/dL)

• Fibrin Glue

  • Sealant in surgical procedures for tight closure of wound

• Platelet Gel

  • Intraoperative combination of autologous platelets, WBC-rich plasma, calcium chloride, and thrombin

  • Stimulates coagulation and healing

(plasma fractionation products) albumin, RHIG, IVIG

• Albumin

  • Used as a volume replacement in trauma, shock, burns, and therapeutic plasma exchange

• Rh immune globulin (RhIG)

  • Administered to prevent alloimmunization against D antigen

• Intravenous immune globulin (IVIG)

  • A product composed of IgG antibodies direct against many antigens

  • Commonly used to treat hypogammaglobulinemia

(plasma fractionation products) hyperimmune globulins & coag factor concentrates

• Hyperimmune globulins

  • Specific immune globulins prepared from donor plasma with high titers--used as passive immunity for MMR, CMV, tetanus, varicella, Hep B and others

• Coagulation factor concentrates

  • Used to prevent or treat bleeding episodes in patients with coagulation deficiencies

  • Factor VIII, Factor IX, Factor XIII, Factor VII, fibrinogen and more

(transfusion therapy; pharmaceuticals) DDVAP & vitamin K

• Desmopressin (DDAVP)

  • reduces or prevents bleeding in patients with mild hemophilia A or type I von Willebrand disease

• Vitamin K

  • can reverse the effects of oral anticoagulants overdose

(transfusion therapy; pharmaceuticals) erythropoietin & thrombopoietin

• Erythropoietin

  • recombinant EPO used to treat anemia in patients with renal failure

• Thrombopoietin

  • recombinant TPO stimulates platelet production in patients suffering from bone marrow suppression that has caused thrombocytopenia

(transfusion therapy; pharmaceuticals) colony stimulating factors & plerixafor

• Colony-stimulating factors

  • HPC donors and granulocyte donors receive this medication prior to donation

  • Used for treatment of neutropenia after chemotherapy in cancer patients

• Plerixafor

  • used as a stem cell mobilizer for patients with non-Hodgkin’s lymphoma or multiple myeloma

(transfusion therapy; pharmaceuticals) antifibrinolytics & recombinant factor VIIa

• Antifibrinolytics

  • inhibits fibrinolysis and commonly used during cardiac surgery to reduce bleeding

• Recombinant factor VIIa

  • used as a supplement for patients with Factor VII deficiency and treating patients with Hemophilia A/B

massive transfusion (general)

Replacement of one or more total blood volumes within 24 hours or about 10 units of blood in adult

• critical first step: establishing intravenous access

• Crystalloid solutions may be used to restore circulating systemic volume to avoid circulatory collapse

• Infusion of FFP, platelets, cryoprecipitate aid in restoring hemostatic function

• Rapid infusers and blood warmers commonly used

• Clinical status of patient and inventory of transfusion service assessed regularly to evaluate any changes

transfusion committee

• Consists of members representing both laboratory and clinical areas

• Review of all elements required by Standards

  • Ordering practices, patient identification, adverse events, near-misses, inventory management, blood administration policies

• Cases of massive transfusion often reviewed by transfusion committee

  • Proper patient identification, appropriate blood usage, patient needs met

• Routinely involved in drafting or reviewing emergency preparedness plans

(transfusion therapy) testing for anti-CMV

• In immune-suppressed individuals, CMV infection can cause debilitating effects and even death

• The two methods to decrease risk of transfusion-associated CMV transmission

  • Leukoreduction

  • Testing blood donors for antibodies to CMV to provide CMV-negative units

(transfusion therapy) hemoglobin S testing 

• RBCs selected for transfusion to a patient diagnosed with SCD (or neonates) should test negative for hemoglobin S

• Screening methods include use of the Hgb solubility test

  • e.g., Sickledex

• RBC products from sickle cell trait donors should not be transfused into a patient with SCD

  • Phenotypically matched for C, E, K antigens

• Considerations for use of autologous blood

(modifications of cellular components) irradiation

• Used to prevent A-GVHD in recipients (immunocompromised)

• Viable transfused T lymphocytes replicate in recipient, recognize recipient as foreign, then a destructive immune response is mounted against recipient's body

• Gamma irradiation disrupts DNA in WBC nuclei

  • Destroys WBCs' ability to replicate

  • Standard dose: 2,500 cGy (centigray)

• RBCs, PLT, and granulocyte products contain WBCs

(modifications of cellular components) freezing

• Blood from donors with rare RBC phenotypes stored frozen for up to 10 years

• Used for autologous or allogeneic transfusion

• Each unit is phenotyped prior to storage and frozen with a cryoprotective agent (e.g., 20% or 40% glycerol)

• Deglycerolization is performed to wash the cryoprotective agent off from frozen RBCs prior to transfusion

  • open system = 24 hours expiration

  • closed system = good for 2 weeks

• Frozen platelets can be stored for up to 2 years

(modifications of cellular components) washing

• Washing RBC units eliminates 85% of WBCs, 15% of RBC mass, and 99% of plasma

• Process performed as an open system = seal of unit is breached

  • Washed RBCs expire in 24 hrs 

  • Washed PLTs expire in 4 hrs

• Closed system: washed RBCs expire in 2 weeks

• Patients with severe allergic reactions to blood products, e.g., transfused to IgA deficient patients who have antibodies to IgA

• Rare donor units, autologous units