blood donation lecture part 2

Overview of Transfusion Biology

  - Transfusion biology involves understanding the processes and products associated with blood donation and transfusion therapy.

Platelet Transfusions

  - Platelet Donation Methods
    - Pooling: Involves combining platelets from 4-5 individual donors into one bag.
    - Apheresis: Platelets are collected from one individual donor, often used for HLA matched donors, ensuring compatibility and quality.

Apheresis vs. Pooling

  - Apheresis
    - One donor's platelets are collected, allowing for HLA matching.
    - Plasma is returned to the donor, minimizing blood loss.
    - Apheresis donations take longer (45-60 mins) compared to whole blood donations (15 mins).
  - Pooling
    - Multiple donors’ platelets are combined into one bag, usually having to label the unit based on the Rh factor of the majority of donors.

Storage and Viability of Platelets

  - Platelets must be stored at 20-24°C with constant agitation.
  - pH for viability is critical, aiming to maintain around 6.2. A drop below this affects function.
  - Temperature monitoring is essential; charts are reviewed regularly.

Expected Responses to Platelet Transfusions

  - Following a transfusion, a patient’s platelet count typically rises by 15-25 x 10⁹ per liter within one hour.
  - Critical Platelet Levels:
    - 20,000: Critical level
    - 10,000: Super critical; hemorrhaging risk increases.
    - Normal range: 150,000 to 400,000 per liter.

Indications for Platelet Transfusions

  - Patients experiencing bleeding or very low platelet counts.
  - Conditions where platelets are dysfunctional despite normal counts.

Donation Procedures

  - Preparation: Platelets must equilibrate for an hour post-processing before being agitated for transfusion.
  - Irradiated Platelets: Used to prevent Graft-versus-Host Disease (GVHD).

Compatibility and Selection

  - Platelets should be ABO compatible; give group-specific where possible.
  - Plasma in apheresis units comes from one person, pooling combines multiple individuals.

Factors in Selection

  - Selection considers ABO types and the antibodies in plasma to reduce complications.
  - Frozen Plasma (FP) and Apheresis Plasma (AFFP)
    - Apheresis plasma is collected from single donors, generally in larger volumes compared to traditional frozen plasma, which might consist of components from multiple donors.

Frozen Plasma Use and Storage

  - Frozen plasma can be stored for one year under proper conditions.
  - Must be thawed before use, with a shelf life of 24 hours at refrigerated temperatures post-thaw.
  - Utilized in massive transfusion protocols or liver disease treatment.

Cryoprecipitate

  - Used for low fibrinogen levels in patients.
  - Limited use due to availability of synthetic alternatives.
  - Thawed cryoprecipitate must be used within four hours after thawing.

Blood Inventory Management

  - Larger hospitals maintain extensive inventories; first in, first out policy for shelf-life management.
  - Control mechanisms in place to prevent waste, including redistribution of units nearing expiration.

Transport and Receipt of Blood Products

  - Blood must arrive within specific temperature ranges; red blood cells should not exceed 10°C or drop below 1°C.
  - A tamper-proof seal is mandatory on transportation boxes to avoid contamination.

Summary of Blood Component Shelf Lives

  - Red Cells: 42 days (standard), 21 days (low-volume).
  - Platelets: 5-7 days at room temperature.
  - Frozen Plasma: 1 year.
  - Thawed plasma: 24 hours at room temperature.
  - Cryoprecipitate: 4 hours at room temperature post-thaw.

Training and Compliance

  - Continuous training for staff involved in blood management and transfusion protocols to ensure quality and safety in transfusion medicine.

Conclusion

  - Understanding the complexities of blood donation and transfusion is vital for improving patient outcomes in clinical settings, emphasizing safety, compatibility, and effective management of blood products.