Page 1036 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

H aemolymphatic system 1011

VetBooks.ir 9.13 Table 9.2 Blood transfusion protocol

• Select an appropriate donor. A clinically normal adult horse
should be chosen. The horse should be negative for EIA
virus, have never received a blood or plasma transfusion,
never foaled and have a normal PCV
• Crossmatching is ideal, particularly if the animal has had a
prior transfusion. A major crossmatch identifies
incompatibility of donor RBCs with recipient serum.
A minor crossmatch evaluates the inverse
• Blood should be collected into sterile containers with
anticoagulant (acid–citrate–dextrose or citrate–
phosphate–dextrose). The anticoagulant/blood ratio
should be 1:9
• Blood should be collected using sterile technique.
A healthy horse can donate up to 20% of its blood volume
(approximately 8 litres for a 500 kg horse) every 30 days.
Blood should be used immediately if possible, but whole
Fig. 9.13 Transabdominal ultrasound image of a foal blood can be stored refrigerated for up to 3 weeks
with haemoabdomen secondary to trauma. Note the • An intravenous catheter should be placed in the recipient.
echogenicity of the peritoneal fluid (arrow), which is Blood must be given via a transfusion filter set to remove
suggestive of haemoabdomen. any clots
• Baseline heart rate, respiratory rate and temperature
client estimates of blood loss, as they are often exces- should be obtained. Blood should be administered at a rate
of 0.1 ml/kg over the first 15 minutes, then increased to
sive. A CBC taken immediately may not reflect 20 ml/kg/h if no adverse reactions are observed. Adverse
blood loss, but in the ensuing hours the haematocrit reactions include tachypnoea, tachycardia, restlessness,
declines as extravascular fluid enters the vascular urticaria, muscle fasciculation and collapse
space to replace lost volume. Over the next several • If adverse reactions are encountered, the transfusion
days, if haemorrhage has ceased, the haematocrit should be ceased and flunixin meglumine (1.1 mg/kg i/v)
and MCV should increase and the MCHC should given. If anaphylaxis is encountered, adrenaline
(epinephrine) (0.01–0.02 mg/kg of 1:1,000 i/v) should be
decrease as younger RBCs are released into circu- administered, along with aggressive intravenous fluid
lation. Horses do not release sufficient numbers of therapy. Corticosteroids (prednisolone sodium succinate,
polychromatophils to easily determine the presence 4.5 mg/kg i/v) are often administered concurrently. If the
of regeneration, and therefore serial haemograms reaction was mild, transfusion can be recommenced 15–30
minutes after flunixin administration. If adverse reactions
should be used to follow the clinical progress. Total redevelop or the reaction was severe, the blood should be
protein concentration should decrease approximately discarded, and another source obtained
in proportion with RBC concentration if external • Transfused RBCs have a short lifespan (4–6 days), so the
blood loss has occurred. If not, internal haemor- beneficial effects of blood transfusion will be transient.
rhage should be suspected. Additional diagnostic Icterus and an increase in free bilirubin will be expected
tools might include ultrasonography, radiography, within a few days of transfusion
abdominocentesis, thoracocentesis or palpation p/r
(Fig. 9.13). Excessive blood loss with minor trauma
should prompt evaluation of haemostasis. arterial bleeding. Replacement of lost blood volume is
achieved by administration of fluid therapy and blood
Management products if required. Replacement with a balanced
Cessation of haemorrhage is the primary goal. If electrolyte solution is most often indicated. Blood
active bleeding is still present, direct pressure should transfusion should be considered with severe haemor-
be applied. Surgical intervention may be required for rhage and clinical signs of anaemia (tachycardia, tachy-
internal haemorrhage, severe trauma or uncontrollable pnoea, pale mucous membranes, weakness) (Table 9.2).