Blood: transfusion

• A blood transfusion is the transfer of blood or blood components from one individual (donor) to another (recipient). 
• Infrequently performed in rabbits, but can provide life-saving supportive therapy for conditions such as profound anemia, hypovolemia, coagulopathies and hypoproteinemia.
• A blood transfusion is generally required if the hematocrit decreases to <10-15%, but this depends on the clinical signs and the duration of anemia.

Uses

• Major indication is symptomatic anemia due to:
  • Hemorrhage, eg trauma, surgery, liver lobe torsion, coagulopathy, gastrointestinal ulceration, genitourinary bleeding Uterine adenocarcinoma.
  • Hemolysis, eg heavy metal toxicosis Lead toxicity, immune-mediated disease.
  • Reduced hematopoiesis, eg chronic inflammatory conditions, toxins, chronic renal failure Kidney: renal failure, neoplasia. 
  • Hypovolemia, eg secondary to massive hemorrhage.
  • Thrombocytopenia Hematology: platelet count.
  • Hypoproteinemia Blood biochemistry: total protein Urinalysis: erythrocytes.

Advantages

• Simple technique easy to perform in most practices. 
• Relatively inexpensive.
• Rapid clinical effect. 
• Stabilizes the patient allowing more time to establish a definitive diagnosis and formulate a specific treatment plan.

Disadvantages

• Availability of donors and storage of blood products may be a limiting factor.
• Time intensive.

Alternative techniques

• Alternatives to whole blood transfusion include:
  • Natural colloids, ie blood products.
    • Packed red cells (ideal if anemic patient is normovolemic or has normal total protein).
    • Plasma fresh or fresh frozen (useful for coagulopathies and  hypoproteinemias).
  • Synthetic colloids:
    • Hemoglobin-based oxygen-carrying solutions, eg bovine purified polymerized hemoglobin (Oxyglobin®). 
    • In human medicine, a review suggested that the use of hydroxyethyl starch might increase mortality in critically ill patients.
  • Crystalloids Fluid therapy (+/- hyperbaric oxygen).

Time required

Preparation

• Recipient: 15-30 min.
• Place intravenous Intravenous catheter placement or intraosseous catheter Intraosseous catheter placement.
• Collect blood and/or bone marrow samples prior to transfusion.
• Assess baseline PCV Hematology: packed cell volume and total protein Blood biochemistry: total protein.
• Assess fresh blood smear Hematology: nucleated red blood cells .
• Donor: 15 min. 
• Assess PCV Hematology: packed cell volume and total protein Blood biochemistry: total protein of donor. 
• Calculate transfusion volume required.

Procedure

• Sedate and collect donation: 15-20 min.
• Administration of blood to recipient: up to 4 h.

Decision taking

Criteria for choosing test

• The decision to proceed with a blood transfusion is based on both the clinical condition of the patient and their PCV/platelet count.  
• A transfusion is indicated if:
  • There is a rapid drop in PCV to <15% Hematology: packed cell volume.
  • The rabbit has acutely lost more than 30% blood volume.
  • The blood loss is associated with weakness, dyspnea Dyspnea, ataxia or collapse. 
  • There is ongoing hemorrhage. 
  • There is a poor response to conventional shock therapy with crystalloids and synthetic colloids.

Risk assessment

• Time permitting, a cross-match should be performed prior to transfusion to minimize the risk of a transfusion reaction.