Blood Transfusion in Dogs

Blood products are readily available from animal blood banks in many countries and can also be obtained in-house or from an external donor program.^6,7 About 15 to 20 mL/kg of blood can be safely collected from a dog. There is no need to administer crystalloid solutions during blood collection from dogs. Blood products may also be acquired via cell salvage and autotransfusion techniques.^8,9

Dogs rarely need sedation for blood collection; if sedation is elected, acepromazine should be avoided due to its effects on platelet function. Several other sedative agents can be used. One common combination consists of butorphanol at 0.2 mg/kg IV +/- dexmedetomidine at 1 µg/kg IV for nonsensitive MDR1 breeds, or methadone at 0.2 mg/kg IV +/- dexmedetomidine at 2 µg/kg IV for MDR1-sensitive breeds can be considered.  

Whether selected in-house or from external programs, dogs that are candidates to become blood donors must meet several conditions: 

• Clinically healthy and assessed with annual examinations and testing (see Donor testing)
• 1-8 years of age
• Weigh >20 kg
• Normal body condition 
• Good temperament 
• Updated vaccination status 
• Packed cell volume (PCV) >40% 
• Negative for dog erythrocyte antigen-1 (DEA 1)
  • Ideal canine blood should be DEA 1, DEA 3, DEA 5, and DEA 7 negative and positive for DEA 4.¹
• Readily accessible jugular vein 
• No previous history of receiving blood product transfusions
• No previous history of pregnancy
  • Pregnancy is known to lead to alloantibody formation against erythrocyte antigens.¹⁰ The few studies available about this issue in dogs did not demonstrate that these alloantibodies are associated with increased incidence of transfusion reactions. Nevertheless, until further research is available, it is advised to avoid previously pregnant female dogs as blood donors, except in emergency situations where no other source of blood products is available. 

Blood obtained from closed cavities can be safely used for autotransfusion if there is no evidence of septic, bile, intestinal content, and urine contamination; if the dwelling time in the cavity is fewer than 72 hours; and if no gross clotting is apparent. Neoplastic disease can also be considered as a contraindication to blood product autotransfusion, although the risk of metastatic spreading may be reduced by leukocyte depletion filters.⁹ Blood for autotransfusion can also be collected and processed with cell salvage devices.                                                                                 

Take the donor’s temperature, pulse, and respiratory rate before placing in lateral recumbency. Evaluate the quality and location of the jugular vein before shaving and sterilizing the skin around the jugular vein.

Place the collection bag (available through Animal Blood Resources International) on a gram scale and zero the scale. Flush and fill the line tubing of the collection system and the connected needle with the bag’s anticoagulant. Most commercially available blood bags now use a citrate-phosphate-dextrose-adenine [CPDA-1] or citrate-phosphate-dextrose/adsol preservation solution as an anticoagulant. Avoid kinking or twisting the line tubing to prevent red blood cell (RBC) damage. Clamp the collection line 3 to 4 cm distal from the needle (use a plastic hemostat to avoid damage to the collection line).

Have an assistant compress the thoracic inlet to increase jugular vein distension, then insert the needle in the jugular vein in a cranial direction and with the bevel up (Figure 1). Once blood enters the collection system, remove the hemostat clamp and let blood flow into the tubing and collection bag. 

An assistant should carefully agitate the collection bag back and forth during collection to allow blood to mix with the anticoagulant. Once 405 to 480 g of blood is collected, have an assistant remove the pressure to the thoracic inlet.  (Figure 2). Remove the needle and perform compression over the puncture site for 1 minute. Wrap the jugular site with cohesive bandage wrap for at least 30 minutes to prevent bruising and hematoma formation.

Hemoclip or heat seal the collection line at least 3 cm above the bag to imprint a unique identifying line number on the bag. Identify the collection bag with donor identification, date, time, and amount collected. Record the donation in the donor record, including its weight, vital signs, and PCV/total protein before and 30 minutes after transfusion. Include data about vessel and draw position used, and record any problems that occurred during donation.

In the first 4-6 hours after blood collection, blood can be administered as FWB, be refrigerated and stored as WB, or refrigerated until processing for component therapy. If the latter option is chosen, the collected blood should be stored at 4°C to 6°C (39°F-42°F) until processing. Blood component therapy is commonly used in human medicine and is becoming more frequent in veterinary medicine. Its main advantage is that it permits the veterinarian to tailor therapy more appropriately while avoiding transfusion-related reactions, as it spares the patient exposure to unnecessary blood products. In addition, it makes transfusion medicine more efficient, because a single unit can be divided in multiple components, which can be used for more than one patient. Each blood component has its own indications, advantages, and disadvantages. A summary of all blood components available is described in Table 1.  

The different blood components are mainly obtained by centrifugation; each blood component needs its established times and speeds of centrifugation to obtain the correct blood product components (Figure 3).¹

For example, to obtain packed red blood cells (pRBCs) and fresh frozen plasma (FFP), WB is first centrifuged and then, with the use of a plasma separator, separated into those 2 components (Figure 4). If any solutions are added to pRBCs, this should be clearly indicated in the blood product identification label, as various preservative solutions have different expiration dates. 

During the process of obtaining them, blood products should be handled with care and with aseptic technique to prevent mechanical damage and contamination (ideally in a laminar flow chamber; Figure 5).  

If possible, consider the use of leukoreduction before RBC product storage. Leukoreduction, the process where white blood cells (WBCs) are removed from an RBC unit, is normally performed by passing the blood product through specific filters. Leukoreduction may reduce storage lesions, transfusion reactions, transfusion-related inflammation, and disease transmission.^1,8  Storage lesions consist of changes in RBC metabolism, protein activity and function, phenotype, and morphologic properties induced by storage. Storage lesions were associated with an increase in reactive oxygen species, pro-inflammatory mediators, and microvesicle concentration, with the potential to have deleterious side effects in the blood component transfusion recipient.¹

Stored blood products should be labeled with blood type, donor’s name, collection date, and expiration date (Figure 6). The ideal storage time that preserves the functional qualities of the blood product without significantly increasing storage lesions is still being studied. In the case of WB and pRBCs, although these blood components can be stored for longer periods, it has been suggested to use units with storage time no greater than 21 days (and no greater than 14 days if the recipient is a critically ill patient).^1,3,8  Regarding FFP, whether using “younger” units has benefits to the recipient or not is currently unknown. Currently advised storage times and temperature for FFP are -30ºC to -20ºC (-22°F to -4°F) for 1 year (see Table 2).^1,7

A dedicated refrigerator that records temperature fluctuations should be used for blood product storage. The importance of a dedicated refrigerator should not be underestimated, as a recent study associated the lack of a dedicated blood product refrigerator with the development of hemolysis in the blood product units, leading to 3 fatalities.¹⁴ 

However, if a dedicated refrigerator is not available, a dedicated space may be acceptable. In this case, blood products should be kept separate from other products to avoid chemical and biologic contamination. Frozen products should be stored in a freezer set on manual defrost.

Blood products should be stored vertically, with airspace between each bag, and never in crisper drawers. Blood product storage refrigerators should be opened as infrequently as possible to prevent temperature fluctuations, as this can cause damage to RBC products. Blood products with RBCs should also be inspected and gently rotated every other day to allow mixture of RBCs with the anticoagulant.