Blood Components Preparationand Therapeutic Uses Ishwar Bihana Department of Haematology, PGIMER, Chandigarh.
Introduction In the past whole blood was the only preparation that could be administered to replace red cells, platelets, coagulation factors . In addition to what patient required, This cause unnecessary administration of unwanted cells or plasma constituents. Large volume of whole blood needed to achieve satisfactory replacement of a particular component. A significant advance in transfusion medicine was made when techniques became available for separation of blood in a closed system and patient could be administered specific replacement therapy. One unit of donor’s blood can be utilized for preparation of different components and thus can be benefit more than one patient.
Now a days , whole blood can be separated into various blood components and further derivatives can be obtained from plasma by fractionation. Specific replacement therapy as per patient’s requirement is permissible to administer and avoid transfusion of unwanted constituents of blood. One unit of blood can benefit more than one patient after its separation into plasma, red cell and platelet components.
HISTORY 1628- Sir William Harvey described venous circulation 1665- Richard Lower performed first animal to animal blood transfusions in a dog in london 1667- Jean-Baptiste Denis in France reported successful transfusions of lamb’s blood to humans
History 1818 - James Blundell, a British obstetrician, performed the first successful transfusion of human Blood for the treatment of postpartum hemorrhage. Considered to be Father of Autotransfusion He also devised various instruments for performing Blood transfusions.
Further Developments 1901 –Karl Landsteiner, an Austrian physician, documented the first three human blood groups A, B and O. 1902 - A fourth main Blood type, AB was found by A. Decastrello and A. Sturli. 1914 - Long-term anticoagulants, among them sodium citrate, were developed, allowing longer preservation of Blood. 1926 - The British Red Cross instituted the first human Blood transfusion service in the world.
1940 - Freeze dried plasma was developed. 1940 - Edwin Cohn developed a cold ethanol fractionation proces. Albumin, Gamma globulin and Fibrinogen were isolated and became available for clinical use. 1950 - Glycerol cryoprotectant for freezing red blood cells. 1950 - Carl Walter and W. P. Murphy introduced the plastic bag for blood collection.
1954 – The blood product Cryoprecipitate was developed for people suffering from hemophilia. 1960 - A. Solomon and J. L. Fahey reported the first therapeutic plasmapheresis procedure. 1972 - Apheresis was used to extract one cellular component. 1979 - A new anticoagulant preservative, CPDA-1, which extends the shelf life of whole Blood and red Blood cells to 35 days is introduced.
Blood Products Blood Products Whole Blood One unit of donor blood collected in a suitable anticoagulant-preservative solution and which contain blood cells and plasma. Blood Components A constituent separated from whole blood, by differential centrifugation of one donor unit or by apheresis. Blood Derivatives A product obtained from multiple donor units of plasma by fractionation.
Whole bloodRed cells Granulocytes Plasma Platelets Fractionated (Fresh) frozen products plasma (F(FP) F Vlla* Immune Globulin F Vlll* Cryo AlbuminCryoprecipitate supernatant plasma (CSP) F lX* * Now available as recombinant products
Types of blood components Whole Blood Packed Red Cells Leukocyte Reduced Red Blood Cells Fresh Frozen Plasma Frozen Plasma Platelet Concentrate Cryoprecipitate
Types of Blood Components Blood component preparation is an essential part of the blood transfusion services. These days, it has been realized that the increasing demand for this precious and scarce fluid. Blood needs can only be met by separating it into various components. Thus component separation and administration will help us in rationalizing use of blood. Blood components are prepared using physical properties of blood for e.g. centrifugation whereas blood derivatives use a chemical (e.g. ethanol) in varying concentration and temperature for its separation. Primary goal of component therapy is to provide right component to the right patient in right quantity at the right time in right quality.
Human blood contains many major as well as minor components but broadly from blood bank component separation point of view, it can be divided into: Human blood a) Cellular elements - Packed red cells, granulocytes and platelets (PRP and PC) b) Plasma : Single donor plasma, fresh frozen plasma, cryoprecipitate and cryo-poor plasma
Preparation of Blood Components EQUIPMENTS Collection Bag :- Double, Triple, Quadruple Bag Refrigerated centrifuge Plasma Extractor Cooling water bath Freezer -180C, -800C Blood Refrigerator 1 - 60C Platelet incubator Insulated container for blood transportation
Centrifugation Principle Sediment of blood cells depend on their size as well as the difference of their d ensity from that of the surrounding fluid, visc osity of medium, flexibility of the cells which are temperature dependent
Methods of preparation There are various methods to separate these components and the yield and quality of component depends upon the method applied. Various methods used are; - (a) Gravity separation (b) Low and high speed refrigerated centrifugation (c) Apheresis by cell separator.(a) Gravity separation It is an old time, crude but cheaper method to separate plasma from whole blood
Steps3. The blood is collected in a double or triple bag system.4. Blood is kept hanging overnight at least for 12-16 hours. There is clear plasma above and packed red cells below.5. The supernatant plasma is expressed into the satellite bag, leaving behind, 80-IOOml of plasma.6. Plasma thus collected is called single donor plasma and can be stored for 24-26 days at 4 - 6°C or for 1 year at -20°C or below.(b) Low speed refrigerated centrifugation:-It is used for preparing Platelet Rich Plasma (PRP)(c) High speed refrigerated centrifugation:-It is used for preparing Platelet Concentrate (PC), Fresh Frozen Plasma (FFP) and Cryoprecipitate (CP).
Details High performance centrifuge from Beckman Coulter, type Avanti J-201 with rotor JLA-8.1000. Application: separation or preparation of subcellular components, proteins, precipitates, viruses, nucleic acids, mammalian/insect cells, blood components and elutriation. Technical specifications: 380 V. Technical specifications rotor: fixed angle, maximum 8000 rpm, nominal capacity: 6 x 1000 ml, buckets size (ø)x(H): 95 x 191 mm.
Whole Blood 450 ml of blood 63 ml of anticoagulant solution. Hct-36-44% No components have been removed. Store at 1-6 oC Shelf life- Citrate-Phophate-Dextrose (CPD) - 21 days CPDA-1 (adenine) - 35 days AS-1, AS-3, AS-5 – 42 days Administer through standard blood filter (150-280 micron) Infuse within 4 hours of issue
Whole Blood Drawbacks: After storage for >24 hours, platelets and WBC are non- functional Factor V and VIII (labile factors) decrease with storage Fluid overload Indications: Acute blood loss > 25% TBV
Whole BloodIndication - Acute , active blood loss with hypovolaemia- Exchange transfusionContraindication- Risk of volume overload : Chronic anemia Incipient cardiac failure
WHOLE BLOODAdministration- Must be ABO and RhD compatible- Never add medication to a unit of blood- Use blood administration setDosage1 unit Hct 3 % or Hb 1 g / dL
Packed Red Cellunits with red blood cells and some plasma- with Anticoagulant ACD / CPD / CPDA – 1- Hct ~ 75 – 80 %
Preparation of Packed RBCsPrinciple: RBCs are obtained by removal of supernatant plasma from centrifuged whole blood.Preparation: Centrifuge whole blood unit in refrigerated centrifuge containing the parameters RPM-3850. Acc-4, Decc-5, Time-5 Min, Temp- 40C Express the supernatant plasma with the help of plasma expressor. Double seal the tubing between the primary and satellite bag. Check that the satellite bag has the same donor number as that on the primary bag and cut the tubing between the two seal.Advantages: Oxygen carrying capacity equal to that of whole blood in half the volume. Significantly decrease levels of isoagglutinins, metabolites and electrolytes.
Preparation of Packed RBCsShelf life: (If CPDA1 anticoagulant) -35 daysStorage temp. : 40C (Range is 2-60C)QC Requirements: PCV 80% (Range is 65-80%)Volume: 250- 300 ml.CONTENTS: Red cells- 65-80% Plasma – 20-35% Some platelets, white cells storage lesion by products and anticoagulant preservative solutions.Transfusion Criterias: ABO/Rh specific and compatibleIndications: Restore oxygen carrying capacity symptomatic anemia and surgical blood loss.Effect: 1 unit RBCs should raise HCT -3%, Hb 1 g/dl
Packed Red Cells ( in plasma)Indication - Replacement of red cells in anemic patients - Use with crystalloid or colloid solution in acute blood lossDosage 10 - 15 ml / kgPRC 1 unit Hct 3 % or Hb 1 g/dL
ASA Guidelines forTransfusion of Packed Red Cells in Adults Transfusion for patients on cardiopulmonary bypass with hemoglobin level ≤6.0 g/dL is indicated. Hemoglobin level ≤7.0 g/dL in patients >65 years and patients with chronic cardiovascular or respiratory diseases justifies transfusion. For stable patients with hemoglobin level between 7 and 10 g/dL, the benefit of transfusion is unclear. Transfusion is recommended for patients with acute blood loss more than 1,500 mL or 30% of blood volume. Evidence of rapid blood loss without immediate control warrants blood transfusion. *Ann Thorac Surg 2007;83:S27–86
Red cell aliquots For babies 10-25 mL units. 5 mL/kg will raise Hb by ~1 gm/dL.
Irradiated Red Cells Gamma-radiated to kill the lymphocytes. The lack of T-cells prevents graft-vs-host disease. Use for Severely immunocompromised patients Lymphoma patients Stem-cell / marrow transplants Intrauterine transfusion Units from close “blood relatives” Neonates undergoing exchange transfusion or ECMO Hodgkin’s Disease
Leukocyte poor red blood cellUnit of red blood cells with some plasma,anticoagulant and additive solution Hct ~ 55 – 65 %
Leukocyte poor red blood cellsCentrifugation method - easiest and least cost - least efficient - reduce WBC only 70 - 80% RBC volume ~ 20%
Leukocyte depleted red blood cellsFiltration method easy, quick, but more expensive high efficient remove WBC more than 99.9% ( third generation ) little loss of RBC volume 38
Leukocyte reduced red cellsIndication - Minimizes white cell immunization in patients - Prevention of FNHTR (Febrile Non-Hemolytic Transfusion Reaction ) - Reduces risk of CMV transfusionContraindication - Not prevent graft –vs- host diseaseDosage - same as Packed Red CellAdministration - same as Whole Blood
Granulocyte Concentrate Obtained by apheresis from family members for administration to cancer patients. Contain 1.0 x 1010 granulocytes Pre-treatment with recombinant G-CSF and dexamethasone can yield 4-8 x 1010 granulocytes Stored at 24o C Infuse within 24 hours of collection
Criteria ANC <500 Fever Documented infection (bacterial or fungal) for 24-48 hours Unresponsive to appropriate antibiotics Reasonable hope of marrow recovery
Platelet Rich Plasma (PRP)It is prepared from the whole blood within six-hours of collection, preferably stored at room temperature of 20-24°C.
Steps1. The blood is collected in-CPDA-1 double or triple bag system.2. The blood bags are weighed on a weighing balance and bags weighing equal are placed opposite to each other in the buckets of centrifuge.3. Temperature of the centrifuge is adjusted between 20 -24°C4. The speed of the centrifuge is calculated according to the radius of the arm of the centrifuge rotor.5. The calculated speed for platelet preparation is 1750 rpm for 11 min. in PGI6. After centrifugation, the bags are taken out from centrifuge chamber with minimal disturbance and the PRP is expressed from the primary bag into the satellite bag with the help of a plasma expresser. After placing proper knots, labeling the blood group and ensuring the screening status the satellite bag is detached from the primary bag.
7. The PRP for storage can be kept at 22-24°C in a, platelet incubator with constant agitation for a maximum of 48-72.hours (at our centre in PGI).8. As a part of internal quality control 1% of the random components units over a month are tested for pH and yield. For PRP the pH should always be > 6.2 and yield 4.5 x 1010 / bag (Drugs and Cosmetics Act) and 5.5 x 1010/ bag (AABB Technical Manual) and one bag of PRP generally raises the platelet count in the recipient by 5000-10000 / µl.Note: Aspirin and related analgesics affect the platelet function, so the donor for platelets is accepted after 3 days of ingestion of these drugs.
Platelets Concentrate (PC) This supplies the same amount of platelets as PRP, but in lesser volume (40 - 50ml). Principle: Platelets are harvested from whole blood following ‘light spin‘ centrifugation. The platelets are concentrated by heavy spin centrifugation with subsequent removal of supernatant plasma. Steps 1. Blood is collected in the triple bag system only 2. PRP is prepared by following the above mentioned steps 3. After detaching the satellite bags from the primary bag, the PRP in again spun at 4000 - 5000 rpm (high spin) for 4 to 5 minutes. 4. A platelet button is formed at bottom and platelet poor plasma is expressed from the 1st satellite bag to the 2nd satellite bags, leaving behind 40 - 50 ml plasma for platelet button suspension. 5. The platelet concentrate in stored at 20°C-24°C for a maximum of 3 days (at PGI) with constant agitation.
Platelets Concentrate (PC)Shelf life: 3 days in platelet incubator & agitator. 24 hrs if no storage cabinetStorage temp.: 20°C - 24°CQ.C. Requirements: To be prepared within 8 hrs after collection, pH should be 6.2 or more at the end of storage time. Platelet count > 5.5 x 1010 /unit.Volume: 30 to 50 mlContents: Platelet - 5.5 x 1010 /bag Plasma - 30 to 50 ml and some white cellsTransfusion Criteria: ABO / Rh specific and compatibleIndications: Severe thrombocytopenia, qualitative platelet defectsEffect: Increases in platelet count 10,000 / ul per unit
CCI (Corrected Count Increment) should be done at 1 hour and 20 hours post transfusion. It compares observed versus expected increase in platelet count.CCI = platelet increment x body surface area (m2) number of platelets transfused x 1011Percentage platelet recovery (PPR)PPR = platelet increment x weight (kg) x blood volume (75 ml/kg) x 100 number of platelets transfused x volume of product (ml)Platelet refractoriness: is defined as poor increment in platelet count following 2 consecutive platelet transfusion. It is also calculated as follows CCI < 7500 at 1 hour CCI < 4500 at 20 hours
PLATELET CONCENTRATE Dosage 1 unit of PC / 10 kg B.W. Increment will be less in - Spleenomegaly - DIC - Septicemia 1 unit of PC Platelet 5000-10,000 / ul
PLATELET CONCENTRATE Administration should be ABO & Rh compatible After pooling, should be infused as soon as possible Use blood administration or platelet infusion set Must not be refrigerated before infusion
Platelet concentrate(Random Donor Platelets) Differential centrifugation from freshly drawn blood units Volume- 60ml Store at 20-24 o C with constant & gentle agitation Use within 5 days Bacterial contamination a problem 1unit raise the platelet count by 5k-10k/microliter. ABO matched platelets preferable
Single-donor platelets Obtained by plateletpheresis technique. 6 - 8 times as many platelets as in a random-donor unit. Larger volumes and HLA-compatibility results in an increase of 30k-60k. Leukoreduced because of apheresis collection ABO matched platelets preferable Rh negative receive Rh negative platelets
Single Donor Platelet Indication same as random PC special requirement obtain from selected donor Dosage Usually 1pack of SDP = 1 therapeutic dose
Single Donor Platelet Vol ~ 300 ml Administration same as random PC , but ABO compatible is more important Vol ~ 50 – 70 ml
PLATELET CONCENTRATE Indications Treatment of bleeding due to Thrombocytopenia Platelet Dysfunction Prevention of bleeding Contraindication prophylaxis of bleeding in surgical patients
Apheresis platelets:This component is equivalent to six random donor platelet units. One unit contains 3 x1011 Platelets.Advantages: 1. Large dose from single exposure 2. Repeat procedure after 72 hours is possible 3. HLA matched platelets can be given 4. Decreases chances for allo-immunisation and transfusion transmitted diseasesDisadvantages: 1. Expensive 2. Time consuming
Fresh Frozen Plasma Plasma along with anticoagulant preservative Volume ~ 250-300 ml Prepared from blood within 8 hrs of donation Maximum level of labile and non-labile clotting factors (about 1 IU per ml) V & VIII, proteins C and S, complement, and immunoglobulins. Good for 24 hours post thaw Then it can be stored for 5 days as liquid plasma (labile factors V and VIII decreased) Shelf life: 1 year
Fresh Frozen Plasma (FFP)It is prepared from the whole blood collected in a CPDA-1 double or triple bag system within 6-8 hours of its collection.Principle: Plasma is separated from cellular blood elements and frozen to preserve the activity of labile coagulation factors.Steps1. Blood is collected in a CPDA-1 double or triple bag system.2. The blood bags are weighed in a weighing balance and bags weighing equal are placed opposite to each other in the buckets of the centrifuge.3. The temperature of the centrifuge is adjusted at 4 - 6°C.4. The bags are subjected to a high spin (3850 rpm) centrifugation for 5 min.5. After the centrifuge stops, the blood bags are taken out with minimal disturbance and supernatant plasma is expressed into the satellite bag, with the help of a plasma expressor, leaving behind 80-90ml.6. After labeling the group and ensuring screening status, the plasma is stored at -20°C or below. The storage shelf life is one year at -20°C and 5 years at -70 to-80°C
Fresh Frozen Plasma contains coagulation factors and other plasma protein (per unit or bag)Volume - 200-250 mlFactor VIII - 0.6 IU / mlFactor IX - 0.9 IU / mlFibrinogen - 250-300 mg / bagProteins - Albumin, globulin, etc.1 IU / kg of factor VIII or factor IX raises the factor VIII levels in plasma by 2% and factor IX levels by 1% respectively.Shelf life: One yearStorage temp.: -20°C or belowQ. C, Requirements: The entire proems of preparation and freezing should be completed within 8 hrs after collection.Volume: 50 to 200 ml
Indications for FFP Transfusion Clinically significant deficiency of Factors II, V, X, XI DIC Plasma exchange Immunodeficiencies Massive transfusion of stored blood. Liver disease Urgent reversal of warfarin therapy Correction of known coagulation factor deficiencies for which specific concentrates are unavailable Correction of microvascular bleeding in the presence of elevated (> 1.5 times normal) PT or PTT Correction of microvascular bleeding secondary to coagulation factor deficiency in patients transfused with more than one blood volume and when PT and PTT cannot be obtained in a timely fashion
FFP Dose 10-15 ml/kg of FFP For warfarin reversal, 5-8 ml/kg of FFP Contraindication Volume expansion Immunoglobulin replacement Nutritional support Wound healing
FRESH FROZEN PLASMA Precaution Acute allergic reaction are common Anaphylactic reaction may occur Hypovolemia alone is not an indication for use Dosage Initial dose of 15 - 20 ml / kg
FRESH FROZEN PLASMA Administration Must be ABO compatible Infuse as soon as possible after thawing ( within 6 hrs ) using standard blood administration set
FROZEN PLASMA Plasma which separate from whole blood at any time during storage. Contain all non-labile coagulation factors. Indication Treatment of stable coagulation deficiencies Contraindication same as FFP
Single Donor Plasma Prepared from stored blood Poor in coagulation factors Cannot be used to correct coagulation factor deficiencies Effective as volume expander
Solvent- Detergent Plasma Plasma from multiple donors is pooled Added a mixture of solvent (tri-n-butyl phosphate) & detergent (Triton X-100) Inactivate lipid enveloped infectious agents Disadvantages: Risk of contamination of nonenveloped agents Expensive
Other Types Donor Retested Single Donor Plasma IgA Deficient Fresh Frozen Plasma
CRYOPRECIPITATECryoprecipitate is the cold – insoluble portion of plasma that precipitates when 0 FFP is thawed between 1-6 C
Cryoprecipitate (C.P) Cryoprecipitate contains precipitated proteins of plasma, rich in factor VIII and fibrinogen, obtained from FFP prepared within 6-8 hours of collection, subsequent thawing at 4- 60 C and removal of supernatant. Also the advantage of Cryoprecipitate is that we can administer large amount of factor VIII without overloading the recipient, especially in pediatric patients. Principle: Coagulation factor VIII can be concentrated by cryoprecipitation of freshly collected plasma. Cryoprecipitation is accomplished by rapid freezing of plasma and slow thawing at low temperature.
Cryoprecipitate (C.P) Cryoprecipitate contains (1 unit)Volume - 10-20 mlFactor VIII-C - 80-120 IUFactor VIII R: Ag - high levelsFactor VIII vWF - high levelFibrinogen - 150-200mg / bagFactor XIII - 20-30% of original level
Cryoprecipitate (C.P)Shelf life: Frozen - 1 year Thawed - 6 hoursStorage temp: Frozen - -20°C or lessQ. C. Requirements: Thaw at 37°C Factor VIII: C-80 units/bagVolume: 10 to 20mlContents: Factor VIII: C - 80 to 150 units/bag Fibrinogen - 150 to 250 mg/bag Factor Xlll - 20 - 30% of whole blood von Willebrand factor - 40-70% of whole bloodTransfusion Criteria: ABO compatibility not requiredIndications: Correction of factor VIII deficiency (Hemophilia A, von Willebrand disease).
Cryoprecipitate Indication Quantitative and Qualitative Fibrinogen Deficiency : DIC von Willebrand Disease Factor XIII deficiency Uremic Coagulopathy Fibrin Glue Factor VIII ( haemophilia A )
CRYOPRECIPITATE Administration Dose of Cryo is based on the desired target level of the specific factor to be replaced ABO compatible if possible no compatibility testing required After thawing & pooling, infuse as soon as possible through blood admin. Set must be infused within 6 hours of thawing
Fresh Whole Blood Heavy spin,4oC(within 8 hrs)Packed Red Cells Fresh Plasma oStored in 1- 6 C Freeze -80oC immediately o Stored at < -18 C
Fresh Whole Blood Light spin, 22oC(within 8 hrs)Packed Red Cells Platelet Rich Plasma Heavy spin,22oC Platelet Concentrate Fresh Plasma Store at 22oC Freeze(FFP)
Fresh Frozen Plasma Thaw at 4oC & heavy spin Cryoprecipitate Cryoremoved Plasma-Refrozen within 1 hr Freeze -80oC immediately o-Store at < - 18 C Stored at < -18oC
Component Storage Red blood cells: 1-6°C Platelets: 22-24°C, with continuous agitation Plasma: FFP: ≤ -18°C (after thawing ~ 1-6°C for 24 hours) FP: ≤ -18°C (after thawing ~ 1-6°C for 24 hours) CSP: ≤ -18°C (after thawing ~ 1-6°C for 24 hours) Cryoprecipitate: ≤ -18°C (after thawing ~ 20°C for 4 hours)
How long can Blood Componentsbe Stored? Red cells: 42 days, collected in CP2D/AS-3 35 days, collected in CPDA-1 Platelets: 5 days with continuous agitation Cryo: 12 months at -18°C or 4 hours after thawing Plasma: 12 months at -18°C or (FFP/FP/CSP) 24 hours after thawing
Left:Freezer filled with FFP and Cryo.Upper Right:Refrigerator with RBC units.Lower Right:Platelet Storage.
Temperature Monitoring Systemfor blood product storage Temperature chart and alarm system
Frozen Deglycerolized Red Cells RBCs are glycerolized and frozen < -65 o C for as long as 10 years Good only for 24 hours after thawing Deglycerolization washes away plasma and WBC Reduces FNHTR, allergic reactions and CMV risk Advantages Blood of rare types can be stored for long periods Reduce risk of transfusion hepatitis Safer in massive blood transfusion Prompt tissue oxygenation Does not prevent GVHD
Plasma Derivatives Factor VIII Concentrate Factor IX Concentrate AT-III Concentrate Factor XIII concentrate Albumin IV Immunoglobulin Rh Immunoglobulin
Albumin Prepared from large pool of plasma reconstituted in isotonic electrolyte solution 96% albumin and 4% globulin and other proteins Heat treated to prevent viral transmission Available as 5% or 25% solutions T1/2=16 hours Used for Hypovolemia or hypoproteinemia Can be given without regard to ABO blood type & cross match
CMV- Negative Blood Products For Pregnant women Newborns Immunocompromised.
Quality control of blood components At least 1% of total components prepared are subjected to quality control at random. The individual parameters to be assessed are as follows and should be fulfilled by at least 75% of the components tested. 1. Platelet rich plasma & Platelet concentrates Platelet rich plasma Platelet concentratesVolume 250 ± 20ml 50±10mlTotal platelet count/bag 4.5-5.5x1010 4.5-5;5x1010pH during storage ≥6.2 ≥6.2and on the day ofexpiry (3rd day)Gross appearance swirling present, no swirling present, no evidence of any evidence of any discoloration/turbidity discoloration/turbidity
2. Single donor apheresis concentratesVolume is 200ml approximatelyTotal platelet count ≥ 3 x 1011/ bagpH > 6.2 at end of storage.3. Fresh Frozen plasma and Cryoprecipitate Factor Vlll concentration is measured by factorVII assays using commercial available factor VIII deficient plasma. Factor Vlll level should; to.e 0.6 l.U. per ml; in case of Fresh Frozen Plasma more than 80 I.U. per bag in case of cryoprecipitates Fibrinogen is measured by dry clot weight method. Fibrindgen level should be 250-300 mg/bag in FFP and 150 mg/bag in case of cryoprecipitates.
Apheresis (Hemapheresis) The word apheresis is derived from a Greek word which means separation. Apheresis also known as hemapheresis is removal of whole blood from donor / patient, separation into components, retention of desired or unwanted components and reinfusion of remaining constituents to the donor or patient.
Indications A. Collection of components from healthy donors Plateietpheresis Plasmapheresis Erythrocytapheresis (2 RBC procedure) Neocytapheresis Leucapheresis Peripheral blood stem cells (PBSC) B. Removal of pathological components from patients i. Therapeutic plasma exchange ii. Therapeutic leucapheresis iii. Therapeutic thrombocytapheresis iv. Therapeutic red-cell, exchange - - Techniques 1. Manual method 2. Cell separators Manual method It is performed using refrigerated centrifuges and specialized plastic bag systems. Blood which is collected in the primary bag is centrifuged to separate the desired component which is retained in the satellite bag and the remainder is infused through the same vein back to the donor. Advantages: Simple and less expensive method Disadvantages: The amount of component prepared per procedure is less than that collected from cell separators. The risk of returning red cells to the wrong patient if stringent donor identification is not done.
Cell separators Apheresis machines using centrifugal force and differing densities of various blood components is used for separation of desired components. Types a) Intermittent flow centrifugation (IFC) - Hemonetics V-50, S-30, MCS. b) Continuous flow centrifugation (CFC) - Fenwal CS 3000, Fenwal CS 3000 plus, Amicus, COBE Spectra. Donor selection for apheresis procedure Plateletpheresis donors • Donors should be healthy individuals meeting the standard criteria for normal blood donation as mentioned in chapter 1. • Donor should have a minimum platelet count of 1.5x 105 / ul. • The interval between two procedures should be at least 48 hours and the amount of red cell loss should not exceed 25 ml / week. • The donor should not have taken salicylates and anti-platelet drugs for last 72 hours. • The validity of mandatory tested infectious disease markers is taken upto 3: days, if a repeat procedure is done in that time frame.
Plasmapheresisdonors • Serial plasmapheresis donors (donating at interval of less than 48 hours) shou : preferably be less than 50 years of age and have had given blood previously c- one or two occasions. • Occasional plasmapheresis donor (no more than once in 4 weeks) are accepted on the same criteria as mentioned for whole blood donation in chapter 1. • Total blood count and total serum proteins should be within normal range. • The maximum amount ofplasma which an individual can donate in one sitting should not exceed 500 ml if the weight is between 50-65 kg and no more than 900 ml if the weight is more than 65 kg. • Adequate replacement fluid should be given to donor if more than 500 ml of plasma is drawn. • If the red cells are not reinfused back to the donor, the donor should be deferred for 12 weeks. • No more than two procedures should be done in one week.
Leucapheresis Leucapheresis is defined as the removal of white cells with the return of red cells, plasma and platelets to the donors. The granulocyte concentrate must contam minimum of 1.0 x 1010 granulocytes in atleast 75% of the units tested. The product should be transfused as soon as possible -after collection. The maximum shelf life is 24 hours. The granulocyte collection yield by apheresis procedure (cell separator) can be increased by: • Increasing the granulocyte count of the donor .by giving steroids or haematopoietic growth factors. • By improving the separation with addition of red cell aggregating agents. e.g. hydroxyethyl starch (HES).
Neocytapheresis In patients requiring repeated transfusions e.g. Thalassemia major, the administration of relatively young cells .(Neocytes) would improve the management of such patients, by decreasing the frequency of transfusion and the rate of iron loading. The neocytes for transfusion purposes are prepared by the use of automated cell separator on the principle that young, larger and less dense red cells are expressed earlier than older cells. Neocytes obtained in such a manner show improved survival but are expensive and take approximately 3-4 hours of donor time.
Erythrocytapheresis / 2 RBC collection procedure For collection of negative RBC units, e.g. O negative Advantages: 1. Standardized RBC mass collection is possible. 2. Metered anti-coagulantobviatesmixing during collection, thus reducing clot formation. 3. Reduces the risk of hypovolemia to the donor. 4. On line separation of RBC and plasma is possible. 5. Anti-coagulant to whole blood ratio is 1:16, thus decreases citrate foxicity. 6. Use of smaller gauge needle is possible. ^ Deferral Period: After 2 RBC procedure, the donor is deferred for 16 weeks.
Adverse effects of Apheresis Citrate toxicity may occur in the form of numbness and tingling sensation around the mouth if the amount of citrate infused exceeds the bodys ability to metabolize it. This problem can be solved by decreasing the rate Of i nfusion of anti-coagulant or by giving exogenous calcium to the donor. The other side effects are similar to that of normal blood donation.
Therapeutic Apheresis Therapeutic plasma exchange and plasmapheresis If 500 ml of plasma is removed without any replacement fluid, the term plasmapheresis is used. For e.g. to prepare anti Rh immunoglobulin, donors are hyper-immunized to Rh antigen. If more than the above amount is removed the lost plasma proteins is replaced by crystalloid and colloidal solution. Replacement fluids for plasma exchange Exchange volumes vary between 1-1.5 times the plasma volume of the patient
Replacement Advantages Disadvantages AdvantagesLow costCrystalloid • and disadvantages of replacement fluids • No coagulation factors • No risk of disease • No immunoglobulins transmission • Hypo-oncotic •Albumin • No risk of disease • No coagulation factors transmission • No immunoglobulins • Iso-oncotic • CostlyPlasma Protein • Less expensive than • Induction of some hypotensiveFractions (PPF) albumin reactionFresh Frozen • Maintains normal level of • Disease transmission if notPlasma (FFP) coagulation factors tested properly • Immunoglobulin & plasma • Citrate overload protein