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Basics ⬇

Basics

Overview

  • Classified as acute or delayed, immune mediated or not immune mediated.
  • Severe reactions usually occur during or shortly after transfusion.
  • Can occur with any blood product, including hemoglobin-based oxygen-carrying solutions.

Signalment

  • Dogs and cats
  • No sex predilection
  • All ages affected

Signs

Acute Hemolytic Reaction

  • Restlessness
  • Fever
  • Tachycardia
  • Vomiting
  • Tremors
  • Weakness
  • Incontinence
  • Collapse
  • Shock
  • Oliguria
  • Loss of transfusion efficacy

Delayed Hemolytic Reaction

Loss of transfusion efficacy-usually no clinical signs.

Acute Non-hemolytic Reaction

  • Anaphylactic reaction-fever, urticaria, erythema, angioedema, and pruritus.
  • Transfusion of contaminated blood-acute septicemia, fever, and shock.
  • Circulatory overload/rapid transfusion-vomiting, distended jugular veins, dyspnea, cough, cyanosis, and congestive heart failure.
  • Citrate toxicity-hypocalcemia, myocardial depression, and weakness.
  • Hyperammonemia-encephalopathy.
  • Hypothermia-shivering and impaired platelet function.

Causes & Risk Factors

Purebred cats and previously transfused dogs have a higher risk of severe transfusion reaction than other animals.

Acute Hemolysis

  • Blood group mismatch.
  • Naturally occurring autoantibody (particularly in cats).
  • Acquired autoantibody (IHA).
  • Transfusion of damaged and hemolyzed RBCs (after inappropriate storage, excessive heating, freezing, or mechanical damage).

Delayed Hemolysis

  • Immune reaction to minor red cell antigens; occurs after 3–14 days.

Acute Non-hemolytic Reaction

  • Anaphylaxis and immune reaction to donor leukocytes or platelets, major histocompatibility complex antigens, or plasma antigens, resulting in release of inflammatory mediators and pyrogens.
  • Transfusion of contaminated blood-lack of aseptic collection and storage conditions.
  • Circulatory overload-rapid transfusion; excessive volume of blood in small patients or in patients with heart failure or oliguric renal failure.
  • Citrate toxicity-after circulatory overload, particularly in small patients or in patients with hepatopathy.
  • Hyperammonemia-high ammonia concentration in stored blood; important only for animals with hepatopathy.
  • Hypothermia-rapid transfusion of refrigerated blood to small or already hypothermic patients.

Delayed Non-hemolytic Reaction

  • Transmission of blood-borne disease-use of infected donor (hemotropic Mycoplasma spp. DNA found in 10% of active donors in one study).
  • Transfusion-associated graft vs. host disease-rare, but >90% fatal complication of transfusion of blood components that contain immunocompetent donor T-lymphocytes. Has not been clearly reported in canine or feline patients yet.

Diagnosis ⬆ ⬇

Diagnosis

Differential Diagnosis

  • Hemolysis-rule out ongoing fulminant hemolytic disease (IHA, Babesia, Mycoplasma) and use of hemolyzed blood.
  • Fever, hypotension-rule out underlying infectious and inflammatory diseases, bacterial contamination.

CBC/Biochemistry/Urinalysis

Hemoglobinemia, leukocytosis, bilirubinemia, hemoglobinuria, and bilirubinuria.

Other Laboratory Tests

  • Repeat cross-match to confirm incompatibility.
  • Bacterial culture or Gram staining of contaminated blood may reveal organism.
  • Mycoplasma PCR in cats.

Treatment ⬆ ⬇

Treatment

Medications ⬆ ⬇

Medications

Drug(s)

  • For hemolysis-rapid-acting corticosteroid, such as prednisolone sodium succinate (11 mg/kg once) or dexamethasone sodium phosphate (2.2 mg/kg once); heparin (dose still controversial, 300 U/kg SC q6h; not for use in bleeding patients).
  • For urticaria, fever-diphenhydramine (1–2 mg/kg); dexamethasone sodium phosphate (0.2 mg/kg once); continue transfusion afterwards, if clinically indicated.
  • For septicemia-broad-spectrum IV antibiotics
  • For volume overload-furosemide 2–4 mg/kg IV, oxygen supplementation.

Follow-Up ⬆ ⬇

Follow-Up

Patient Monitoring

  • Check attitude, temperature, vital signs, lung sounds, PCV, total solids, and plasma color before, during, and after transfusion.
  • For acute hemolytic reactions or septicemia-monitor CVP and urine output.
  • If pulmonary thromboembolism is suspected, check chest radiographs and arterial blood gases frequently.

Prevention/Avoidance

  • Carefully record any transfusion reaction in the patient's medical file.
    • Pretransfusion testing:
    • Screen donors for infectious disease.
    • Blood type donors and recipients.
    • Typing cards/cartridges (DMS, Alvedia, DMS/Agrolabo, DMS/Abaxis).
    • Crossmatching: Gel agglutination or strip tests (Diamed, DMS, Alvedia).
  • Adhere to standard transfusion protocols (e.g., use of healthy donors; appropriate blood collection, storage, and administration techniques).
  • Initially, transfuse at 0.5 mL/minute.

Possible Complications

  • Fulminant hemolysis may cause acute renal failure, pulmonary thromboembolism, multiorgan thromboembolism, DIC, and cardiac arrhythmias.
  • Volume overload may cause heart failure.
  • Cardiac arrest.

Expected Course and Prognosis

  • Acute course in most animals.
  • Prognosis good in stable animals, guarded in severely ill animals or when not recognized early.
  • Cats with type B blood receiving mismatched blood have the worst prognosis.

Miscellaneous ⬆

Miscellaneous

Abbreviations

  • CVP = central venous pressure
  • DIC = disseminated intravascular coagulation
  • IHA = immune hemolytic anemia
  • PCR = polymerase chain reaction
  • PCV = packed cell volume
  • RBC = red blood cell

Author Jörg Bucheler

Consulting Editor Alan H. Rebar

Suggested Reading

Sullivan L, Hackett TB. Transfusion Medicine: Best Practices. In: Bonagura JD, Twedt DC, eds., Current Veterinary Therapy XV: Elsevier, 2014, pp. 309–313.