Blood Products
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This article is still under construction. |
| See also: | Transfusion Medicine - Introduction Blood Groups - Dog Blood Groups - Cat Blood Collection for Transfusion |
Production of Blood Products
Whole fresh blood is commonly used in general practice and administered straight away to the patient. Additionally whole bood can be stored or separated into various blood components. Blood components are very useful as they reduce the number of transfusions necessary and also replace specific losses.
If fresh whole blood undergoes slow centrifugation (1100tr/min for 10 mins at 22 o C) then Platelet rich plasma is produced. This can be stored for 3 days at an ambient temperature.
If fresh whole blood undergoes fast centrifugation (2500tr/min for 20 mins at 5 o C then both plasma and red blood cells become separated. Red blood cells can then be stored at 2-60C for 4 weeks. Fresh plasma must be used for the 6 hours following production unless it is frozen at -20oC where it becomes fresh frozen plasma and can then be stored and used for the next 2 years.
Types of Blood products available
Fresh Whole Blood (FWB) can be collected from a healthy donor and combined with anticoagulant which can then be used for up to 8 hours. Whole blood contains all blood components which are Red blood cells, Platelets, White blood cells, Coagulation factors and plasma proteins. This is indicated for for dogs and cats suffering from anaemia, thrombocytopaenia or a coagulopathy with active bleeding.
Stored whole blood (SWB) is FWB collected and stored at 2-6 o C and can be used for up to 4 weeks. It can be useful for patients requiring red blood cells and plasma proteins as the other components will no longer be viable. This can be used to treat anaemic patients who are hypovolaemic.
Packed Red Blood Cells containing only red blood cells are given to patients suffering from anaemia but who are normovolaemic to provide additional oxygen carrying cells.
Fresh Frozen Plasma (FFP) contains coagulation factors and plasma proteins. It can be stored at -20 oC for up to a year. Its use is indicated in patients with Von Willebrand's disease, Haemophilia A ad B, Disseminated Intravascular Coagulation, other coagulation factor deficiencies, hypoproteinaemia, acute pancreatitis and systemic inflammatory response syndrome.
Stored Frozen Plasma (SFP) is FFP that has been thawed and refrozen or FFP which is more than a year old. It can be administered in patients with hypoproteinaemia but will have lost many of its coagulation factors.
Platelet Rich Plasma is used in cases of platelet dysfunction, thrombocytopaenia, it can also be used for coagulopathies in the first six hours of storage. Platelets and plasma protein are present including all coagulation factors.
Cryoprecipitate is produced from FFP that has been thawed slowly and then centrifuged at 5000RPM for 5mins at 4oC. The plasma is then removed leaving a small amount of cryo. It contains Von Willebrands Factor, Factor VIII and XII, fibrinogen, and fibronectin. It is the blood product of choice in the treatment of Von Willebrands disease, Haemophilia A and hypofibrinogenaemia. Cryoprecipitate can be stored for one year after collection.
Oxyglobinis a very useful blood product as it increases plasma haemoglobin concentration. It is produced from bovine haemoglobin and is licenced for use in the dog but not for the cat. Oxyglobin is indicated in cases of severe anamia of any cause.
When recieving oxyglobin patients should be monitored for the development of circulatory overload.
Administration of Blood products
Are normally administered intravenously however if this is not possible then the intraosseous route can be used. Plasma products need to be thawed prior to administration, red blood cell products can normally be given straight away. An in-line filter is required for all blood products.
The rate the transfusion should be administered also varies but generally cn be started at 0.25-1.0ml/kg for the first 20 minutes and can then be increased if no problems are encountered.
The amount of product to give will vary on the patient's state, the product being used and the response to the product.
Generally the PCV will increase by 1% for every 10-22ml/kg administered.
References
Transfusion Therapy. Lymphoreticular and Haematology module. 4th year notes. Royal Veterinary College London. 2009.
Selected Topics in Canine and Feline Emergency Medicine. Volume 1. Handbook for the veterinary practitioner. Royal Canin.