Page 610 - Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice

598 SPECIAL THERAPY

to effect. 26 Hypothermia is common after large-volume normal heart rate) or hyperkalemia (decreased height of
transfusion in veterinary patients, and use of warming P waves, loss of P waves, or widening of the QRS complex
blankets should be instituted whenever possible. Dilution with large T waves) ifrapidmeasurement of serum electro-
of coagulation factors by large-volume transfusion of lyteconcentrations cannotbeobtained. Venous access and
coagulation factor-depleted stored blood results in blood pressure should be maintained by an infusion of a
prolongation of coagulation times. In dogs receiving crystalloid solution such as lactated Ringer’s solution or
large-volume transfusions, prolongation of coagulation 0.9% NaCl. Intravenous administration of short-acting
times is associated with a poor prognosis. 62 Administra- glucocorticoids may suppress some of the mediators of
tion of fresh frozen plasma is indicated to correct the acute hemolytic transfusion reactions and lessen the clini-
coagulation abnormalities. cal progression, but their efficacy in transfusion reactions
Any transfusion can cause circulatory overload. Dogs has not been evaluated in veterinary patients. When the
and cats with chronic severe anemia or compromised evaluation of a patient with a suspected transfusion
cardiac and pulmonary systems are at greater risk for reaction suggests that an acute hemolytic transfusion reac-
circulatory overload and pulmonary edema than are those tion is occurring, the blood typing and crossmatching
without cardiopulmonary disease. Dogs and cats devel- must be repeated to determine whether a laboratory error
oping volume overload from transfusion are treated with is responsible for the reaction. In patients with fever,
oxygen supplementation, diuretics, and vasodilators. without evidence of hemolysis, the transfusion may be
Improvement should be seen within 1 to 2 hours. restarted if the Gram stain is negative for bacterial
contamination.
DELAYED NONIMMUNOLOGIC It is important to recognize the late effects of transfu-
TRANSFUSION REACTIONS sion and not mistake them for another disease process.

In humans, human immunodeficiency virus, hepatitis Delayed transfusion reactions usually are managed with
virus, and cytomegalovirus infections are documented supportive care. The only specific treatment for a delayed
as late effects of transfusion. One late complication transfusion reaction consists of treating a transfusion-
of transfusion described in veterinary medicine is acquired infection appropriately.
hemochromatosis. 104 A Schnauzer received blood
transfusions every 6 to 8 weeks for 3 years to treat chronic PREVENTION STRATEGIES
anemia. Hemochromatosis was confirmed by necropsy A special effort is not necessary to prevent transfusion
when the dog was euthanized because of progressive reactions. By simply following the transfusion guidelines
liver disease. discussed here with reference to donor selection, blood
typing, blood storage, and administration, most transfu-
EVALUATION OF A PATIENT WITH A sion reactions can be prevented. Crossmatching should
SUSPECTED TRANSFUSION be included in the guidelines for providing a safe blood
REACTION transfusion. Major and minor crossmatches detect
When an acute transfusion reaction is suspected, immedi- antibodies in the plasma of the donor or recipient capable
ate intervention is critical because of the life-threatening of causing an acute hemolytic transfusion reaction; how-
nature of acute transfusion reactions. In all animals ever, a transfusion reaction may still occur despite a com-
suspected of having some form of acute transfusion reac- patible crossmatch. Crossmatching does not prevent
tion, the transfusion should be stopped and samples of sensitization to red blood cell antigens, which may result
patient blood and urine obtained for baseline evaluation in a hemolytic reaction during future transfusions because
of biochemical, hematologic, and coagulation values. it detects only antibodies that are currently present in
The unit of blood should be inspected to ensure it is the donor or recipient. It should be performed routinely
from the appropriate speciesand is the intendedunit based in veterinary clinics either by a commercially available gel
on the crossmatch or blood type. A Gram stain and tube method (DMS Laboratories, Inc., Flemington,
bacterial culture of the blood remaining in the blood N.J.) or by the tube method. A tube crossmatch is
bag should be submitted to the laboratory. Urine can be described below.
visually inspected to determine the presence or absence
ofhemoglobin. Rectal temperature ofthe recipient should Crossmatch Procedure
be compared with the pretransfusion value. A transfusion- Performing a crossmatch is an intimidating but simple
associated fever is defined as an increase in 1 F over the procedure once all the equipment is assembled

pretransfusion temperature. 118 The cardiovascular system (Box 24-4). Several descriptions of the procedure have
should be monitored by electrocardiogram and blood been published, all of which describe the same basic pro-
pressure measurement. Immediate evaluation of serum cedure with minor variations. 14,35,103 Not all protocols
ionized calcium and potassium concentrations are critical, recommend the use of phosphate-buffered saline; others
but certain electrocardiographic changes serve as surro- have an additional step at the end using species-specific
gate markers of hypocalcemia (long QT– interval with a Coombs reagent to increase test sensitivity, and some