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Blood Bank

Plasma

The liquid matrix of blood. While it might look like just yellowish fluid, it’s packed with essential proteins crucial for coagulation, immunity, and maintaining osmotic pressure. For transfusion purposes, we’re primarily interested in its coagulation factors

What is Plasma?

  • Definition: Plasma is the largest component of blood (~55% by volume), primarily composed of water (~92%) but containing vital dissolved substances:
    • Proteins: Albumin (maintains osmotic pressure), Globulins (including immunoglobulins/antibodies), Fibrinogen, and all other Coagulation Factors (Factors II, V, VII, VIII, IX, X, XI, XII, XIII, etc.)
    • Other Solutes: Electrolytes (sodium, potassium, chloride, etc.), nutrients (glucose, amino acids, lipids), hormones, and waste products (urea, CO₂)
  • Function in Transfusion: The primary goal of transfusing plasma is to replenish deficient coagulation factors to treat or prevent bleeding

Types of Plasma Components for Transfusion

The key difference between plasma products lies in how quickly they were frozen after collection, which impacts the preservation of labile coagulation factors (Factors V and VIII are the most sensitive to degradation):

  • Fresh Frozen Plasma (FFP)
    • Preparation: Plasma separated from whole blood and frozen solid at ≤ -18°C (or colder) within 8 hours of collection (if collected into CPD, CPDA-1) or within 6 hours (if collected into ACD). Can also be collected by apheresis
    • Key Feature: Considered the “gold standard” as rapid freezing best preserves all coagulation factors, including the labile Factors V and VIII
    • Volume: Typically ~200-275 mL per unit
  • Plasma Frozen within 24 hours (PF24)
    • Preparation: Plasma separated from whole blood and frozen solid at ≤ -18°C within 8 to 24 hours of collection
    • Key Feature: Contains clinically effective levels of most coagulation factors, but may have slightly lower levels of Factor V and Factor VIII compared to FFP. For most clinical situations requiring factor replacement, PF24 is considered equivalent to FFP
    • Volume: Similar to FFP (~200-275 mL)
  • Plasma Frozen within 24 hours held at Room Temperature (PF24RT24)
    • Preparation: Plasma separated from whole blood held at room temperature (20-24°C) for up to 24 hours, then frozen solid at ≤ -18°C within 24 hours of collection
    • Key Feature: Logistical advantage for processing. Factor levels are comparable to PF24 (slightly lower Factor V/VIII than FFP)
    • Volume: Similar to FFP/PF24
  • Thawed Plasma
    • Preparation: Any of the above frozen plasma products (FFP, PF24, PF24RT24) that have been thawed
    • Storage: Stored at 1°C to 6°C after thawing
    • Key Feature: Factor V and VIII levels decline significantly during refrigerated storage after thawing. Can be used for up to 5 days, but is not ideal if specific replacement of labile factors is critical after the first 24 hours
  • Liquid Plasma
    • Preparation: Plasma separated from whole blood that has never been frozen
    • Storage: Stored at 1°C to 6°C
    • Key Feature: Very low levels of labile Factors V and VIII. Limited use, primarily for patients needing plasma exchange who don’t require labile factors. Shelf life is tied to the original whole blood expiry + up to 5 days
  • Cryoprecipitate-Reduced Plasma
    • Preparation: The supernatant plasma remaining after Cryoprecipitated AHF has been removed from thawed FFP
    • Key Feature: Deficient in Fibrinogen, Factor VIII, Factor XIII, and von Willebrand Factor. Its main use is in plasma exchange for patients with Thrombotic Thrombocytopenic Purpura (TTP), as it lacks the large vWF multimers implicated in TTP pathogenesis
  • Source Plasma
    • Preparation: Collected by plasmapheresis specifically for further manufacturing into plasma derivatives (like Albumin, IVIG, Factor Concentrates). Not typically intended for direct transfusion

Indications for Transfusion

Plasma transfusion is indicated for:

  • Replacement of Multiple Coagulation Factor Deficiencies: In patients who are actively bleeding or at high risk of bleeding due to:
    • Severe Liver Disease (impaired factor synthesis)
    • Disseminated Intravascular Coagulation (DIC) (factor consumption)
    • Massive Transfusion (dilution and consumption of factors)
  • Urgent Reversal of Warfarin (Coumadin): When Vitamin K is too slow and Prothrombin Complex Concentrates (PCCs) are unavailable or contraindicated
  • Plasma Exchange Procedures: For conditions like TTP, Guillain-Barré syndrome, Myasthenia Gravis
  • Rare Specific Factor Deficiencies: If specific factor concentrates are unavailable (e.g., Factor V deficiency)

Contraindications Plasma should NOT be used for:

  • Volume expansion alone (use crystalloids or albumin)
  • Nutritional support
  • When specific factor concentrates or Vitamin K are more appropriate and available

Storage and Expiration

  • Frozen State (FFP, PF24, PF24RT24, Cryo-Reduced Plasma)
    • Storage Temperature: ≤ -18°C (≤ -30°C preferred for better long-term stability)
    • Expiration: 1 year from the date of original collection
  • Thawed State
    • Storage Temperature: 1°C to 6°C
    • Expiration:
      • As “Thawed FFP/PF24”: 24 hours after thawing
      • Relabeled as “Thawed Plasma”: 5 days after thawing (acknowledging lower labile factor levels)
  • Liquid Plasma
    • Storage Temperature: 1°C to 6°C
    • Expiration: Up to 5 days past the original whole blood expiration date

Administration

  • Thawing: Rapidly at 30-37°C in a monitored water bath or FDA-approved microwave/thawing device. Overwrapping is crucial in water baths to prevent port contamination
  • Compatibility: Plasma units MUST be ABO compatible with the recipient’s RED BLOOD CELLS. This means:
    • Group O recipient can receive O, A, B, AB plasma
    • Group A recipient can receive A, AB plasma
    • Group B recipient can receive B, AB plasma
    • Group AB recipient can receive only AB plasma (Universal plasma donor)
    • Rationale: The antibodies (anti-A, anti-B) are in the donor plasma and must not react with the recipient’s red cell antigens
    • Rh Type: Generally not considered critical for plasma transfusion itself, as plasma contains negligible RBCs. However, hospital policies may prefer Rh-compatible plasma
  • Dosage: Typically 10-20 mL/kg body weight, adjusted based on clinical situation and coagulation results (e.g., INR, PTT)
  • Filtration: Administered through a standard blood filter (170-260 microns)
  • Infusion Time: Usually infused over 30-60 minutes, but must be completed within 4 hours of thawing (or spiking the bag)

Potential Risks / Adverse Reactions

  • Transfusion-Related Acute Lung Injury (TRALI): A leading cause of transfusion-related mortality. Often associated with antibodies (anti-HLA or anti-neutrophil) in donor plasma reacting with recipient WBCs. Risk mitigated by using plasma predominantly from male donors, or female donors tested negative for HLA antibodies
  • Transfusion-Associated Circulatory Overload (TACO): Risk due to the volume infused, especially in susceptible patients (elderly, cardiac/renal impairment)
  • Allergic Reactions: Range from mild urticaria (hives) to severe anaphylaxis
  • Febrile Non-Hemolytic Reactions (FNHTRs)
  • Transfusion-Transmitted Infections (TTIs): Very low risk due to donor screening and testing
  • Citrate Toxicity: Possible with rapid, large-volume infusions (especially in patients with liver impairment) due to citrate anticoagulant binding calcium

Key Terms

  • Coagulation Factors: Proteins in plasma essential for blood clot formation
  • Labile Factors: Factors V and VIII, which degrade relatively quickly if not frozen promptly
  • FFP (Fresh Frozen Plasma): Plasma frozen within 8 hours of collection
  • PF24 (Plasma Frozen within 24 hours): Plasma frozen within 8-24 hours of collection
  • Thawed Plasma: Previously frozen plasma stored at 1-6°C, expires in 24 hours or 5 days
  • TRALI (Transfusion-Related Acute Lung Injury): Serious pulmonary complication potentially linked to donor antibodies
  • TACO (Transfusion-Associated Circulatory Overload): Pulmonary edema due to excessive volume infusion
  • ABO Compatibility (Plasma): Donor plasma antibodies must be compatible with recipient red cell antigens (e.g., Group A recipient needs A or AB plasma)