Case study: Myths of transfusion medicine (Part two of a two-part series)

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Myth 4: Autotransfusion requires specially prepared kits

In 2016 Robinson et al. described autotransfusion in dogs using a two-syringe technique.

Blood is collected in a sterile manor during surgery from a haemabdomen with a 60mL catheter tip syringe

It is then transferred to a 60mL luer tip syringe

This can either be transferred into a sterile empty saline fluid bag (100mL, 500mL, or 1 L) and administered with a filtered blood-giving set. Or can be connected to an 18 micro haemonate filter and administered with an extension set. Take care not to pressure infuse through the small 18 micro filter. It is recommended to change the filter every 50 mLs.

transfusion medicine
Fig 1: A 60-mL catheter tip syringe that has been used to collect blood from the abdomen. 

Alternate Method

Abdominocentesis or thoracocentesis with a large 14 guage catheter or 18 guage needle or butterfly catheter connected to a short administration set, three-way tap and 50mL syringe.

Place a standard fluid giving set into a 1 L bag of saline 0.9% and allow all fluid to drain.

Connect the end of the giving set to the three-way tap. You now have a closed collection method to collect blood from the abdomen or thorax

Anticoagulation

Adding anticoagulant to autologous blood is controversial. Blood becomes defibrinated when in contact with the thoracic or abdominal serosal surfaces for more than one hour. Therefore, blood that has been in contact with a peritoneal surface for more than one hour may not require anticoagulation prior to autologous blood transfusions. When active haemorrhage is the source of autologous blood, the addition of anticoagulant may be warranted. It has been recommended in the veterinary literature to add either 0.05–0.14 mL of anticoagulant per mL of collected blood. (~1mL anticoagulant per 10mL blood).

transfusion medicine
Fig 2: Luer tip of 60mL syringe (*) is inserted into catheter tip to transfer blood.

Myth 5: red blood cells are destroyed when frozen

In 1950, it was first demonstrated that human red blood cells (RBC) could be cryo- preserved, thawed, washed free of cryoprecipitates and transfused with normal in vivo survival of 85-90% of the recovered cells. High cost, difficulty in preparation and short shelf life of thawed RBCs were deterrents that dampened the enthusiasm for frozen RBC usages. Advancement in technology with the introduction of ACPTM 215 Haemonetics cell processing system (ACP 215) has led to numerous military organisations across the world now utilising this lifesaving resource on the frontline. The Australian Red Cross supplies the Australian Defence Force with frozen RBCs.

Deglycerolized red blood cells have been used by the US military for half a century, starting with the Vietnam War. Deglycerolized red blood cells have a frozen storage life of 10 years, but require special equipment to thaw and deglycerolize. The available data show no difference in either efficacy with complications when compared to standard product red blood cells.

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Fig 3: Luer tip syringe, blood filter, extension set, and needle used to autotransfuse the blood.

Cryoprotecting agent is essential to prevent the dehydration and mechanical trauma to RBC during freezing. Cryoprotecting agents are classified as penetrating and non-penetrating. Glycerol is a penetrating group of cryoprotecting agent. The high concentration of glycerol in RBC prevents formation of ice crystals and consequent membrane damage. Infusion of incompletely deglycerolized RBC has negligible effect except for a shift in intracellular fluid volume. Polyvinylpyrrolidone, hydroxyethyl starch (HES), polyethylene oxide are non penetrating cryoprotecting agents as they require high rates of cooling in liquid nitrogen at -196 °C. Non penetrating cryoprotecting agents protect cells by a process called ‘vitrification’, where they form a glassy shell around the cell. HES is one of the promising cryoprotecting agents for cryopreservation of RBC, since its removal from thawed RBC prior to transfusion is not required.


DR ELLIE LEISTER BVSc FANZVCS

Dr Ellie Leister is the Pet Intensive Care Unit Veterinary Manager at Veterinary Specialist Services in Brisbane.

In 2004, Dr Leister spent four years in mixed practice in country NSW before sitting memberships and moving to England where she started to focus more on small animals and her passion for emergency and critical care started.

Dr Leister has worked exclusively as a critical care veterinarian in the Pet Intensive Care Unit at VSS in Brisbane since returning in 2012. She manages a team of 20 people and the ICU operates 24/7.

The PICU is known nationally a one of the most well run and busiest critical care centers in the country. It manages very complex cardiology, oncology, medical and surgical cases as well as everyday emergencies.


References:

Robinson D, et al. Autotransfusion in dogs using a 2-syringe technique. Journal of Veterinary Emergency and Critical Care. 2016 26(6)

Higgs VA, et al. Autologous blood transfusion in dogs with thoracic or abdominal hemorrhage: 25 cases (2007–2012). Journal of Veterinary Emergency and Critical Care. 2015, 25(6), pp 731–738

LTC Andrew Cap, et al. The Use of Frozen and Deglycerolized Red Blood Cells. Military Medicine. 2018, 183, 9/10:52.

Noorman F, van Dongen TTCF, Plat M-CJ, Badloe JF, Hess JR, Hoencamp R. Transfusion: -80ÊC Frozen Blood Products Are Safe and Effective in Military Casualty Care. 2016. PLoS ONE 11(12)

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