Blood Component Preparation and Therapy

Objectives of Blood Component Preparation and Therapy

• Explain the specific benefits associated with component separation.

• Define the term "storage lesion" and provide a comprehensive list of biochemical elements that change during the blood storage period.

• Compare various anticoagulant and preservative solutions, focusing specifically on their expiration dates and chemical contents.

• Illustrate the sequential steps involved in blood component preparation.

• Identify the most appropriate blood component for transfusion based on specific patient clinical conditions.

• State the exact storage temperatures and storage time limits for every specific blood component.

• Determine if component products meet acceptable American Association of Blood Banks (AABB) standards and Food and Drug Administration (FDA) guidelines based on laboratory quality control (QC) test measurements.

• Explain the regulatory intent and specific activities of the FDA regarding the preparation, storage, and distribution of blood components.

• List labeling requirements applicable to all blood components and discuss the advantages of the International Society of Blood Transfusion (ISBT) 128 system.

• Discuss the necessity of monitored storage equipment and the specific requirements for alarm systems.

• Describe the essential aspects and protocols for safe blood administration.

Blood Collection and Storage Systems

• Primary Collection:

  • Blood is collected into a primary bag that contains specific anticoagulants and preservatives.

  • The standard volume of blood collected is approximately $450\,mL$ plus $63\,mL$ of Citrate Phosphate Dextrose (CPD) or approximately $350\,mL$.

• Closed System:

  • The blood collection set is manufactured as a sterile, closed system.

  • This includes the primary bag, attached satellite bags, and all connected tubing.

  • The integrity of the closed system prevents bacterial contamination.

• Open System:

  • If the sterile system is compromised—for example, if ports or other areas are exposed to air—it is classified as an open system.

  • Open systems have significantly shorter expiration times due to the risk of contamination.

Anticoagulant-Preservative Solutions and Additives

• Mechanism of Action: Anticoagulant-preservatives work in tandem to prevent the clotting of blood and extend the functional storage life of red cells.

• Volume Requirements:

  • The standard volume of anticoagulant-preservative solution is $63\,mL$ or $70\,mL$.

  • If the volume of whole blood collected is less than $300\,mL$, the volume of the anticoagulant-preservative solution must be reduced proportionally to maintain the correct anticoagulant-to-whole blood ratio.

• Specific Chemical Components and Functions:

  • Dextrose: Supports the generation of Adenosine Triphosphate (ATP) via the glycolytic pathway.

  • Adenine: Functions as a substrate to facilitate Red Blood Cell (RBC) ATP synthesis.

  • Citrate: Prevents coagulation by chelating calcium (making it unavailable for the clotting cascade).

  • Sodium Biphosphate: Acts as a buffer to prevent an excessive drop in $pH$.

• Preservative Solution Lifespans:

  • Acid Citrate Dextrose (ACD): $21\,\text{days}$.

  • Citrate Phosphate Dextrose (CPD): $21\,\text{days}$.

  • CPD with 2 dextrose (CP2D): $21\,\text{days}$.

  • CPD with adenine (CPDA-1): $35\,\text{days}$.

• Additive Solutions (AS):

  • Additives extend the storage time of RBCs to $42\,\text{days}$.

  • These must be added within $72\,\text{hours}$ of whole blood collection.

  • AS-1 (Adsol): Contains Saline, Adenine, Glucose (SAG), and Mannitol.

  • AS-3 (Nutricel): Contains SAG plus Sodium Phosphate and Sodium Citrate.

  • AS-5 (Optisol): Contains SAG with different concentrations of ingredients.

  • AS-7 (SOLX): Contains SAG with Citrate and Sodium Bicarbonate.

Storage Lesion: Biochemical Changes in Stored Blood

• Definition: Storage lesion refers to the ensemble of biochemical changes that occur when blood is stored at $1-6\,^{\circ}\text{C}$. These changes impact RBC viability and functionality.

• Acceptable Shelf Life Criteria:

  • At least $75\%$ of the transfused RBCs must remain in the recipient's circulation $24\,\text{hours}$ post-transfusion.

  • Hemolysis in the unit must be less than $1\%$.

• Specific Biochemical Changes (The Storage Lesion):

  • Decreased: Glucose levels, Adenosine Triphosphate (ATP), and $2,3\text{-Diphosphoglycerate (2,3 DPG)}$.

  • Increased: Potassium ($K^+$) and Lactic Acid.

  • Functional Impact: A decrease in $2,3\text{ DPG}$ leads to a decreased ability to exchange oxygen ($O_2$) because the hemoglobin binds oxygen too tightly and does not release it to tissues effectively.

Blood Component Preparation Steps

1. Initial Centrifugation (Light Spin): Whole blood is centrifuged at a low speed.

2. Expression: Platelet-Rich Plasma (PRP) is expressed (pushed) into a satellite bag, leaving the RBCs in the primary bag.

3. Additive Inclusion: Additive solution is added to the RBCs (if applicable), followed by optional leukoreduction.

4. Sealing: The RBC bag is sealed and cut off from the system.

5. Second Centrifugation (Heavy Spin): The PRP is centrifuged at a high speed.

6. Separation: Plasma is expressed from the platelets into a separate bag.

7. Platelet Finalization: Platelets are sealed and stored at room temperature (producing random donor platelet concentrates). A small amount of plasma remains to maintain a $pH$ of at least $6.2$.

8. Plasma Processing: The remaining plasma can be further processed into:

   • Fresh Frozen Plasma (FFP): Frozen within $8\,\text{hours}$.

   • Plasma Frozen within 24 hours (PF24).

   • Cryoprecipitate: Created by thawing FFP and collecting the cold-precipitate.

Whole Blood (WB)

• Composition: Consists of all blood components (RBCs, WBCs, platelets, and plasma).

• Storage Parameters:

  • Storage Temperature: $1-6\,^{\circ}\text{C}$.

  • Shipping Temperature: $1-10\,^{\circ}\text{C}$.

• Expiration:

  • CPD/CP2D: $21\,\text{days}$.

  • CPDA-1: $35\,\text{days}$.

• Clinical Indications:

  • Active bleeding (massive blood loss).

  • Exchange transfusions.

• Expected Response: One unit increases Hemoglobin ($Hgb$) by $1\,g/dL$ and Hematocrit ($Hct$) by $3\%$.

• Complications: High risk of Transfusion-Associated Circulatory Overload (TACO) and loss of viable platelets/coagulation factors over time.

• Requirements: Must be ABO identical and crossmatched.

Red Blood Cell (RBC) Components

• Storage Parameters:

  • Temperature: $1-6\,^{\circ}\text{C}$.

  • Shelf Life: $21\,\text{days}$ to $42\,\text{days}$ depending on the preservative/additive.

  • Shipping Temperature: $1-10\,^{\circ}\text{C}$.

• Indications: Surgical and post-surgical bleeding, oncology patients, renal dialysis patients, sickle cell anemia, thalassemia, active bleeding, and premature infants.

• Donor-Recipient ABO Compatibility:

  • Recipient O: Can receive Donor O.

  • Recipient A: Can receive Donor A or O.

  • Recipient B: Can receive Donor B or O.

  • Recipient AB: Can receive Donor A, B, AB, or O.

Specialized RBC Modifications

• Leukocyte-Reduced RBCs:

  • Purpose: Prevents febrile non-hemolytic reactions, HLA immunization, and reduces transmission of Cytomegalovirus (CMV).

  • Standard: Final unit must contain less than $5 \times 10^6$ White Blood Cells (WBCs).

  • Method: Filtration (in-line before storage or bedside during transfusion).

  • Note: Does not prevent Graft-Versus-Host Disease (GVHD).

• Apheresis RBCs:

  • Collection: 1 unit every $8\,\text{weeks}$ or 2 units every $16\,\text{weeks}$.

  • Criteria: Final unit must have at least $51\,g$ of hemoglobin and a minimum volume of $153\,mL$.

• Frozen RBCs:

  • Indications: Storing rare units or extending the life of autologous units (up to $10\,\text{years}$).

  • Cryoprotective Agent: Glycerol is added to prevent ice crystal formation.

  • High-Glycerol Method: $40\%$ Glycerol, stored at $-65\,^{\circ}\text{C}$.

  • Low-Glycerol Method: $20\%$ Glycerol, initial freeze at $-196\,^{\circ}\text{C}$, stored at $-120\,^{\circ}\text{C}$.

• Deglycerolized RBCs:

  • Process: Thawed in a $37\,^{\circ}\text{C}$ water bath and washed with decreasingly osmolar saline to remove toxic glycerol.

  • Expiration: $24\,\text{hours}$ (due to being an open system).

• Washed RBCs:

  • Indications: Patients with IgA deficiency and anti-IgA antibodies, or those prone to severe allergic/anaphylactic reactions.

  • Process: Washed with normal saline; results in a $20\%$ loss of RBCs and an expiration of $24\,\text{hours}$.

• Irradiated RBCs:

  • Purpose: Prevents Transfusion-Associated Graft-Versus-Host Disease (TA-GVHD) by inactivating T-cell proliferation.

  • Dosage: $2500\,cGy$ (or $25\,Gy$) at the center; minimum dose of $1500\,cGy$.

  • Expiration: Becomes $28\,\text{days}$ from the date of irradiation.

  • Side Effects: Membrane damage leads to higher plasma potassium and lower ATP/2,3-DPG.

Platelet Components

• Function: Maintain vascular integrity, form platelet plugs, and contribute to fibrin formation.

• Indications: Chemotherapy, hematopoietic progenitor cell transplant, postoperative bleeding.

• Storage: $20-24\,^{\circ}\text{C}$ (room temperature) with continuous gentle agitation.

• Expiration: Usually $5\,\text{days}$; can be $7\,\text{days}$ if using FDA-approved containers and bacterial detection (e.g., Verax PGD test).

• Metrics:

  • Random Donor Platelet concentrate: Minimally $5.5 \times 10^{10}$ platelets.

  • Single Donor Apheresis: Minimally $3 \times 10^{11}$ platelets (equivalent to a pool of 5-6 random donors).

  • Response: One unit should increase the count by $5000-10,000/\mu L$.

• Refractoriness: Unresponsiveness to platelet transfusion defined by a Corrected Count Increment (CCI) of less than $5000/\mu L$ at $10\,\text{minutes}$ to $1\,\text{hour}$ post-transfusion.

  • CCI Formula: $\text{CCI} = \frac{(\text{Postplt} - \text{Preplt}) \times \text{BSA}}{\text{Platelets Infused}}$

Plasma and Cryoprecipitated AHF

• Fresh Frozen Plasma (FFP):

  • Frozen within $8\,\text{hours}$ of collection.

  • Stored at $-18\,^{\circ}\text{C}$ for up to $1\,\text{year}$.

  • Thawed at $30-37\,^{\circ}\text{C}$; stored at $1-6\,^{\circ}\text{C}$ for up to $5\,\text{days}$ after thawing.

• PF24: Frozen within $24\,\text{hours}$; lower in labile factors like Factor VIII.

• Cryoprecipitated Antihemophilic Factor (CRYO):

  • Cold-insoluble precipitate from FFP.

  • Contains: von Willebrand Factor (vWF), Fibrinogen, Factor VIII, Factor XIII, and Fibronectin.

  • QC: Must have $150\,mg$ fibrinogen and $80\,IU$ Factor VIII per unit.

  • Usage: Treatment for Factor VIII or fibrinogen deficiency, and for making "Fibrin Glue" (topical) for surgical bleeding.

• Plasma Compatibility:

  • Recipient A: Receives A or AB.

  • Recipient B: Receives B or AB.

  • Recipient AB: Receives AB only.

  • Recipient O: Receives O, A, B, or AB.

Granulocytes, Apheresis

• Indication: Absolute neutrophil count < 0.5 \times 10^3/\mu L with bacterial/fungal infection.

• Content: At least $1.0 \times 10^{10}$ granulocytes plus platelets and $20-50\,mL$ of RBCs.

• Storage: $20-24\,^{\circ}\text{C}$ for only $24\,\text{hours}$.

• Requirements: Must be crossmatched due to RBC content; must be irradiated to prevent GVHD.

Regulatory and Administrative Safety

• Labeling (ISBT 128):

  • Required since May 1, 2008.

  • Labels must include: Donation ID number, ABO/Rh group, product code, expiration date/time.

• Equipment Requirements:

  • Refrigerators and freezers must have recording devices (checked every $4\,\text{hours}$) and audible alarms with 24-hour response.

• Transport Temperatures:

  • RBCs/Whole Blood: $1-10\,^{\circ}\text{C}$.

  • Platelets: $20-24\,^{\circ}\text{C}$.

  • Frozen Plasma/Cryo: Shipped on dry ice.

• Administration:

  • Positive ID of patient and sample is mandatory.

  • Only normal saline ($0.9\%\,NaCl$) can be administered with blood.

  • Use a standard $170\,\text{micron}$ filter.

  • Infusion must be completed within $4\,\text{hours}$.