Transfusion Medicine

Blood Typing

  • Canine Blood Typing

    • Individual test for DEA negative or positive.
    • One line = negative, two lines = positive.
    • Questionable positive: Assume DEA positive. Faint line still means positive (compare to pregnancy test).

  • Feline Blood Typing

    • Blood types: A, B, or AB.
    • Cats can only receive same type transfusions.
    • Rare AB blood should get type A first if no AB donors, type B as secondary choice.
How to Run Canine/Feline Blood Typing Test
  1. Place 3 drops buffer solution into the well of the test.
  2. Absorb 10 microliters of blood using a stir stick (no heparinized blood). EDTA, ACD, CPD usable.
  3. Stir for 7 seconds.
  4. Cover test cartridge.
  5. Insert cartridge into well and wait for migration (1-2 minutes).
  6. Replace cover to read results.
  7. Enter results in SmartFlow and EZy Vet.

Blood Smear Preparation

Steps for Preparing a Blood Smear
  1. Create smear on a microscope slide with a small blood amount (1 drop optimal).
    • Direct patient sample preferred; avoid clotted blood.
    • Use EDTA tube within 1 hour to avoid aggregation.
  2. Stain smear (Diff-Quick)
    • Fixative (solution 1 - blue): Dip 7 sec.
    • Eosinophilic Stain (solution 2 - red): Dip 7 sec.
    • Basophilic Stain (solution 3 - purple): Dip 9 sec.
  3. Rinse with distilled water and air dry.
  4. Count platelets in 10 fields at 100x oil lens, average count x 15,000 = estimated number of platelets.
  5. Report results in EZy Vet.

Crossmatching

  • Required after a recent transfusion (3-5 days) unless specified otherwise.
  • Check with a doctor for feline requirements as they may need crossmatches more frequently.
  • Keep blood products to be crossmatched separate for identification.
Process of Crossmatching
  1. Use commercial kits:
    • Donor sample: 0.1ml EDTA whole blood or 0.05ml pRBCs.
    • Recipient sample: 1.0ml serum/plasma.
  2. Follow instructions for samples in color-coded tubes (blue, yellow, green, red) for mixing and centrifuging.
  3. Compare results after spinning:
    • Matching yellow tube with green = negative crossmatch (compatible).
    • Matching yellow tube with red = positive crossmatch (incompatible).
  4. Record and enter results in EZy Vet.

Manual Crossmatch (Major)

Preparation Steps
  1. Wash donor sample (EDTA whole blood) by centrifuging and resuspending in NaCl through multiple washes.
  2. Mix 1 drop donor RBC suspension with 2 drops recipient plasma.
  3. Centrifuge mixed sample and look for macroscopic agglutination to determine compatibility.

Blood Product Handling and Administration

  • Types of Blood Products:
    • Packed Red Blood Cells (pRBC), Fresh Frozen Plasma (FFP), Whole Blood (WB), Frozen Plasma, Frozen Platelet Concentrate, Human Albumin, Canine Albumin.
General Handling Guidelines
  • Store products at specific temperatures.
  • Monitor transfusions via transfusion sheets.
  • Use a filter for blood products (except Albumin and IVIG).
  • Do not mix blood products; use separate lines.
  • Ensure proper labeling and verification before administration.
  • Medications to be given after transfusion completion.

Specifics of Blood Products

  • pRBCs:
    • Store at 1-6 degrees Celsius, viable for 6 weeks.
    • Keep track of bag weight and administer slowly over 4-6 hours.
  • Whole Blood:
    • Good for 21-28 days when not punctured.
    • Used for severe hemorrhage, anemia, coagulopathies.
  • FFP:
    • Fresh Frozen Plasma is good for 1 year; used for clotting factor deficiencies.

Thawing and Administration of Plasma and Platelets

  • Thaw plasma at 30-37 degrees Celsius; use within set time limits.
  • Platelets thawed at room temperature, avoid warm water baths.
  • Infusion rates typically over 1-2 hours.

Transfusion Reactions

Types of Reactions
  1. Febrile Non-Hemolytic Reaction: Common; reacts to donor WBCs.
    • Signs: Fever, lethargy.
  2. Allergic Reaction: Immune response to plasma proteins.
    • Signs: Itching, hives.
  3. Acute Hemolytic Reaction: Severe; blood type mismatch.
    • Signs: Fever, hemoglobinuria.
  4. Delayed Hemolytic Reaction: Subtle, may occur days to weeks later.
  5. Anaphylactic Reaction: Rare but life-threatening.
    • Signs: Sudden collapse, difficulty breathing.
  6. TRALI: Immune-mediated lung inflammation.
  7. TACO: Fluid overload; more common in cats.
  8. Transfusion-Related Sepsis: Infection from contaminated blood.
Immediate Actions for Reactions
  1. Notify doctor and stop transfusion if necessary.
  2. Monitor vitals and administer emergency medications as directed.
  3. Provide support and evaluate bloodwork if needed for further reaction assessment.

Species Differences in Transfusion Reactions

  • Cats prone to hemolytic reactions if not typed.
  • Dogs may have delayed reactions without crossmatching, while also tolerant to first transfusions.
  • Signs of reactions vary in sensitivity between cats and dogs.
Signs of Transfusion Reactions
  • Mild Reactions: Fever, lethargy, vomiting.
  • Moderate to Severe: Increased heart rate, jaundice, hemoglobinuria.
  • Severe Reactions: Anaphylaxis, seizures.