Autologous Blood Transfusions in an Emergency Setting
Beth Guerra, DVM
One of the problems plaguing the veterinary profession is the availability of blood products in an emergency setting. With a dearth of well-established blood banks, most emergency clinics rely on national suppliers or in-house blood donors. For general practices, the options may be more limited.
The most common causes of thoracic and abdominal hemorrhage are vascular trauma, ruptured neoplasia or coagulopathy (usually rodenticide). In a critical setting, there may be a limited amount of time to locate a blood product, perform a cross match or adequately warm the product to the appropriate temperature. An autologous blood transfusion (ABT) involves re-infusing the patient’s blood quickly in an emergency setting. This can be done in-house with equipment that is usually on hand, and once the procedure is established, can require minimal personnel.
The technique can involve direct aspiration from a body cavity or aspiration into a sterile canister during surgery. In the former, centesis is usually performed using a large-gauge needle attached to an extension line and a three-way stopcock. The blood is collected into large syringes or a sterile collection bag. A 210 micron Hemo-Nate® filter is used on the end of the tubing introduced into the patient catheter. The blood is usually drawn straight from the patient’s body cavity and then infused directly back through the IV. For larger volumes, citrate anticoagulant (at the ratio of 0.14ml/ml of blood) can be added to the collection vessel, usually syringes, and blood can be collected in several syringes sequentially before infusing back into the patient.
During surgery, blood can be collected directly from the body cavity using a Poole suction tip with the pressure set at less than 100mmHg to avoid stress to the RBCs. The suction tip should be kept well below the level of the blood to avoid aspiration of excessive air. The blood can be collected into a sterile suction canister, then transferred to either an empty blood collection kit bag or an empty sterile fluid bag with an IV administration set containing a 210 micron filter.
The bag is rolled over and clamped to form a seal.
Ameroid rings placed around the shunting vessel slowly squeeze the vessel obstructing blood flow.
A third method of collection was just described in the November 2016 issue of JVECC. Blood can be collected from the abdomen during surgery using catheter tip syringes, which can then be passed to an assistant. Luer tip syringes can be inserted into the catheter tip to withdraw the blood and then hooked to a filter and the blood administered to the patient.1
The benefit of ABT is obvious: an immediate source of normothermic, compatible blood with no risk of transfusion reactions. It is also much more cost effective compared to banked products, and there is no risk of disease transmission or degradation of 2,3-DPG associated with stored products. The risks include contamination during collection, air embolism or hemolysis of RBCs (either during suctioning or prolonged contact with a serosal surface). Rarely, hypocalcemia can be seen if a large amount of citrate anticoagulant is used.
A recent retrospective study in JVECCS2 identified 25 dogs receiving ABTs. The hemorrhage was localized to abdominal (76%), thoracic (20%) and both (4%). Of the dogs with vascular trauma (56%), the most common causes were GDV with rupture of short gastric vessels, post-op OVH/neuter complications and blunt force trauma. For dogs with rupture neoplasia (32%), sites included renal, splenic or unidentified intrathoracic. The dogs with coagulopathy (12%) were exclusively brodifacoum. In this study, the median transfused volume was 29ml/kg, with the largest volume transfused in ruptured neoplasms. Additional blood products, such as whole blood or FFP, were given in 68% of the cases. It was noted that there was no significant association between survival and etiology of hemorrhage. Investigations in humans have failed to demonstrate an increased metastatic rate with ABTs in patients with ruptured neoplasia; in this study, most of the dogs already had evidence of metastasis at time of ABT.
If your clinic does not have an in-house blood bank, or when products are scarce, ABT can be considered as an alternate source of blood. Establishing ready-made kits and training technical staff in these procedures can make the process routine.
1) Robinson DA, Kiefer K, Bassett R, Quandt J. Autotransfusion in dogs using a 2-syringe technique. J Vet Emerg Crit Care. 2016: 26: 766-774.
2) Higgs VA, Rudloff E, Kirby R, Linklater AKJ. Autologous Blood Transfusion in dogs with thoracic or abdominal hemorrhage: 25 cases. Vet Emerg Crit Care. Nov/Dec 2015;25(6):731-8.