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990 Transfusion Reactions

HISTORY, CHIEF COMPLAINT reactions, clinical signs typically occur several • AHTR: treat for hypotensive shock (IV
Current (acute reaction) or recent (delayed days or longer after a transfusion and may fluids, vasopressor agents for persistent
VetBooks.ir RBCs (pRBCs), platelets, or plasma disorder (e.g., hemolysis). Additional diagnostic • FNHTR: temporarily stop or slow the
hypotension). Glucocorticoids are not likely
present similar to a recurrence of the primary
reaction) transfusion of whole blood, packed
beneficial.
testing may be required based on the type and
PHYSICAL EXAM FINDINGS
Initial signs of a transfusion reaction may be severity of the reaction. infusion rate. If the fever is significant,
antihistamines or nonsteroidal antiinflam-
subtle, but if unnoticed, the recipient’s condi- Differential Diagnosis matory drugs (NSAIDs) might reduce the
tion can rapidly decline. • Hemolysis: underlying hemolytic disorder fever. Discontinue the transfusion if the fever
Clinical signs associated with acute immuno- (p. 59) persists or worsens.
logic reactions: • Fever: acute hemolytic transfusion reaction, • Volume overload: diuretics (furosemide 2 mg/
• Whole blood/pRBCs: vomiting, fever, sepsis, underlying inflammatory or infectious kg IV) and oxygen (p. 1146)
hemolysis (pallor, tachycardia, weakness), pig- disease • Sepsis: obtain samples for culture, IV
menturia, jaundice, anaphylaxis, tachypnea/ • TRALI: volume overload (difficult to antibiotics, and IV fluids
dyspnea, urticaria, pruritus, hypotension distinguish from each other) • Dilutional coagulopathy: transfuse fresh-
(weak pulse), ventricular arrhythmias, apnea frozen plasma if prolonged PT or aPTT
• Platelets: fever, vomiting Initial Database (p. 1169).
• Plasma: urticaria, edema, pruritus, erythema • CBC, serum biochemistry • TRALI: oxygen supplementation, maintain
Clinical signs associated with acute nonim- ○ Hemoglobinemia (red/pink serum; repeat blood pressure (IV fluids ± vasopressors).
munologic reactions: blood sampling to rule out hemolysis Glucocorticoids are controversial; avoid
• Transfusion-related sepsis: signs of sepsis due to collection technique or sample diuretics. May require ventilatory support
(fever, weak pulse, tachycardia), hemoglo- handling) (p. 1185)
binuria, vomiting ○ Bilirubinemia
• Citrate toxicity: vomiting, tremors, tetany, ○ Leukocytosis Chronic Treatment
excessive hemorrhage • Urinalysis: hemoglobinuria, bilirubinuria Recognition of infectious disease may be
• Volume overload: dyspnea, tachypnea, tachy- • Hypocalcemia (ionized): citrate toxicity delayed; treatment varies with pathogen type.
cardia, cough (dry, soft initially), vomiting • Blood pressure: hypotension (p. 1065)
• Dilutional coagulopathy: excessive hemorrhage • Thoracic radiographs Possible Complications
• Improper collection, in vitro hemolysis: ○ Suspected volume overload or TRALI (rule • AHTR and reactions to contaminated blood
vomiting out pulmonary edema) may be severe and require an aggressive
• Hyperammonemia: neurologic signs ○ Enlarged pulmonary vasculature supports therapeutic response. Most other reactions,
Clinical signs associated with delayed immu- fluid volume overload. when detected early, respond to conservative
nologic reactions: • Prothrombin time (PT)/activated partial management.
• Whole blood/pRBCs: fever, jaundice, thromboplastin time (aPTT)/platelet count: • AHTR from contaminated blood: hypo-
premature recurrence of anemia before and during massive transfusions tension, shock, renal failure, disseminated
• Platelets: thrombocytopenia (post-transfusion intravascular coagulation
purpura [rare]), spontaneous hemorrhage Advanced or Confirmatory Testing • Volume overload, TRALI: hypoxemia
Clinical signs associated with delayed nonim- • AHTR: confirm hemolysis in recipient • TRALI: hypotension, hypoxemia
munologic reactions: disease transmission; signs (centrifuge); perform major cross match,
vary with pathogen ideally with pretransfused recipient blood Recommended Monitoring
Clinical signs associated with TRALI: dyspnea (p. 1084); Coombs’ test on recipient Monitor mentation, temperature, vital
(noncardiogenic pulmonary edema), tachypnea • Inspect transfused unit for contamination. parameters, hematocrit before, during, and
○ Dark discoloration, clots, air bubbles after transfusion, with very close monitoring of
Etiology and Pathophysiology ○ In vitro hemolysis (unit and administration mentation and vital parameters (q 15 minutes)
Immunologic: a sensitized recipient mounts an set) through at least the first 60 minutes.
immune response to a specific antigen (cellular ○ Gram stain and culture (aerobic/anaerobic)
or protein) in transfused blood. • Echocardiography (p. 1094) and central PROGNOSIS & OUTCOME
• Acute: patients receiving incompatible blood. venous pressure may help distinguish volume
○ Dogs: usually dog erythrocyte antigen overload from TRALI. • Stable patients: good with early recognition
(DEA) 1.1 incompatibility • Specific testing if infectious disease transmis- and intervention
○ Cats: usually incompatibility with A/B sion suspected (e.g., blood culture, serology, • Critical patients: guarded
blood types; reactions severe in type B polymerase chain reaction [PCR])
cats receiving type A blood. In the United PEARLS & CONSIDERATIONS
States, purebred cats are more likely than TREATMENT
domestic shorthair cats to have type B Comments
blood. Treatment Overview • Pretreatment with antihistamines or glu-
• Delayed: immune response with antibodies Treatment depends on the type and severity of cocorticoids may not prevent immunologic
to minor RBC antigens reaction. In mild reactions, slowing or stopping reactions.
Nonimmunologic: bacterial contamina- the transfusion might be sufficient, but in severe • Severe reactions usually occur during or
tion, improper unit selection, handling, or reactions, aggressive fluid and pharmacologic shortly after transfusion.
administration therapy may be required. Supportive care is • Most AHTRs can be prevented by using
necessary while the cause of the reaction is DEA 1.1–negative canine blood donors (for
DIAGNOSIS identified and corrected. nontyped recipients) and using typed and
matched feline blood donors.
Diagnostic Overview Acute General Treatment • With the discovery of new RBC antigens
For acute transfusion reactions, clinical signs • The initial action should be to stop the (e.g., Mik in cats; Dal in dogs), pretransfu-
usually develop during or immediately after transfusion; it can often be restarted at a sion cross-matching should be performed for
completion of the transfusion. For delayed slower rate when the patient is stable. all cats and all previously transfused dogs.

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