Whole blood (WB) is the preferred product for resuscitation of severe hemorrhagic shock in an MWD. Canine WB contains a biologically balanced ratio of all canine blood products and, as such, is the product most likely to restore effective circulating volume and oxygen carrying capacity while preventing coagulation alterations. Any MWD that requires a transfusion subsequent to trauma-induced hemorrhage should receive WB as the product of choice when available.

The primary blood group classification of clinical significance for transfusion in MWDs is based on the dog erythrocyte antigen (DEA) system. Although approximately 13 antigen specificities have been identified, only the DEA 1 system (particularly DEA 1.1) is of most concern due to its high degree of antigenicity and ability to result in an acute hemolytic transfusion reaction. Naturally occurring anti-DEA 1 alloantibodies associated with acute hemolysis (< 24 hours post-transfusion) are not present in canines; therefore, a cross match prior to a MWD’s first transfusion is generally not necessary in a naïve recipient.17

Note: Transfusion of DEA 1-positive blood to a DEA 1-negative MWD will cause the recipient to develop antibodies against the DEA 1 positive antigen; this places the MWD at risk for future transfusion reactions.

To mitigate the risk of a potential transfusion reaction, the recipient’s blood type and previous transfusion history should always be confirmed prior to any transfusion. A crossmatch compatibility should be done for any MWD that has received a previous transfusion ≥3 days prior to their next transfusion or if previous transfusion history cannot be confirmed. See below section on typing and cross matching.

## HANDLING/STORAGE

- Fresh WB is collected from a donor and ideally administered to the recipient within 4-6 hours of collection.
- After 6-8 hours, the product becomes stored/chilled WB and should be kept at 4-6 degrees Celsius in a refrigeration device approved for chilled blood product storage.
- The shelf life of canine WB at 4-6 degrees Celsius depends on the anticoagulant used when the blood was collected.
- Canine WB should be stored refrigerated for up to 21 days when collected in CPD and up to 28 days when collected with CPDA-1. (Note: the 28 day shelf life of canine whole blood is different than the shelf life of human whole blood based on currently available in vitro data on refrigerated canine whole blood.2)
- WB should never be left at room temperature for longer than 4-6 hours and should never be frozen.
- When transporting canine WB, ensure that it is packaged in appropriate insulated containers on wet ice to maintain proper temperatures.

## DOSAGE

- In most MWDs, a reasonable starting dose for a dogs needing a WB transfusion due to acute blood loss is one 450-500 mL bag (unit) of WB. Goal-directed clinical and laboratory reassessment of MWD should be done after the first bag of WB to determine if more blood is indicated.
  - A rough estimate of 2 ml/kg of WB is required to raise the patient PCV by 1%.
  - The desired target PCV to reach is one that results in sustained improvement of clinical signs and laboratory values for the MWD, usually >20-25%.
  - Simply targeting a normal PCV range may not be necessary and could result in increased risk for undesirable transfusion reactions.
- Transfusions that take longer than 4-6 hours to complete are at risk for bacterial contamination and subsequent adverse effects.
- In a controlled setting involving a hemodynamically stable MWD, start with an initial WB transfusion rate of 0.5 to 1 mL/kg/h for the first 15 minutes and monitor for any adverse transfusion reactions. If no transfusion reactions are observed, increase the rate to provide the remaining amount within 4 hours; recommended WB transfusion rates for normovolemic canines is 5 – 10 mL/kg/h.
- In emergent situations involving severe, acute blood loss leading to trauma-induced hemorrhagic shock, a goal-directed WB transfusion rate of up to 20 mL/kg/h or 1.5 mL/kg/min over 20 minutes can be administered to restore hemodynamic stability.
- Reassess the MWD after the first unit of WB to determine if a subsequent transfusion needed.

## ADMINISTRATION

- When possible, chilled WB should be passively warmed to room temperature over 30-60 minutes prior to administration, or passed through an IV infusion line warmer during administration. A gravity drip with an in-line adult human 170-260 micron filter set is recommended for the administration of canine WB to an MWD unless a blood specific infusion pump is available; WB should not be run through a standard fluid pump in order to preserve the structure of the donor RBCs.18,19
- Administration to the MWD patient should occur through either a dedicated, large-bore (18 gauge or larger) peripheral or central intravenous catheter or an intraosseous catheter within a span of 4 hours. No other fluid therapy or medication administration should occur simultaneously through the same catheter supporting a WB transfusion.
- Administration of WB by gravity flow is recommended in canines. In order to preserve the integrity of donor RBCs,20 it is not recommended to administer WB through an infusion pump unless the pump and administration set are designed and validated for use with blood or other blood component (pRBCs, plasma, albumin, platelets).
- Transfusions that take longer than 4-6 hours to complete are at risk for bacterial contamination and subsequent adverse effects.
- In emergent situations, canine WB can be transfused rapidly to maintain effective circulating volume, oxygen carrying capacity and to prevent cardiovascular collapse. This can be accomplished by one of the below methods:
  - Manually squeezing the bag of whole blood or by placing the bag of whole blood in a pressure sleeve OR
  - Employ a rapid transfusion set (See Figure 1 below.)
    - Spike the blood bag with a standard blood administration set.
    - Connect a 3-way stopcock to the administration set and then connect a 60 mL syringe and an extension set to the 3 way stopcock.
    - Pull blood from the bag into the 60 mL syringe and prime the line and the extension set.
    - Ensure any air is removed from the circuit and connect the extension set to the MWD’s catheter.
    - WB can then be rapidly pushed from the syringe to the MWD and refilled from the bag without disconnecting the set.