Introduction Blood transfusion can be life-saving & many areas of surgery could not be undertaken without reliable transfusion support. Tansfusion of blood & its components carries potential risks, which must be outweighed by the patient’s need.
Blood Group Systems There are more than 400 blood groups have been found The two major blood groups: (1) ABO system (2) Rh system Others: (Kell, Duffy, Kidd)
ABO System Phenotype Antigens Naturally Frequency (%) occuring antibodies O O Anti-A & Anti-B 46 A A Anti-B 42 B B Anti-A 9 AB AB Nil 3
Principles of Cross-match Blood is selected on the basis of ABO & Rh D group. Check compatibility between potential donor red cells & recipient serum. Takes about 40 minutes. O –ve group can be used in extreme emergency situations.
Fresh whole blood Average volume of blood withdrawn is 470mls taken into 63ml of anticoagulant. Refers to the blood that is administered within 24 hours of its donation. Rarely indicated. Poor source of platelets & factor VIII.
Indications: - Acute blood loss - Sickle cell disease - Cardiac surgery
Red cell concentrates Product of choice for most clinical situations. Concentrated suspension of RBCs can be prepared by removing most of the supernatant plasma after centrifugation. The preparation reduces but does not eliminate reaction caused by plasma components. Reduces Na+, K+, lactic acid & citrate administered. Provides oxygen-carrying capacity.
Indications: - Severe anemia - Haemolytic anemia - Anaemia in pregnancy
Platelet concentrates Made either from centrifugation of whole blood or from an individual donor using apheresis. An adult dose is manufactured from 4 separate donations pooled together or 1 apheresis collection. Carry a greater risk of bacterial contamination as they cannot be refrigerated.
Indications: - Leukaemia - Prophylactically to prevent bleeding in patient with bone marrow failure
Fresh frozen plasma Some 200-300ml of plasma can be removed from a unit of whole blood. Prepared by freezing the plasma from 1unit blood at -30C within 6 hours of donation Contains all the coagulation factors present in plasma
Cryoprecipitate A single unit of cryoprecipitate can be removed from 1 unit of FFP after controlled thawing. After resuspension in 10-20ml plasma, the cryoprecipitate is frozen once more to -30oc & can be stored for up to a year. Contains Factor VIII, fibrinogen & von Willebrand factor. Indication: DIC
Factor VIII and IXconcentrates Freeze dried preparation of specific coagulation factors prepared from large pools of plasma recombinant coagulation factor concentrates , treatment of choice for inherited coagulation factor deficiencies. Haemophilia A (VIII) Haemophilia B (IX)
Human albumin Human albumin solution 20% 200 g/L albumin and 130 mmol/L sodium Indicated for treatment of acute severe hypoalbuminemia
Granulocyte concentrate Prepared from single donor using cell separatos and are used for pt with severe neutropenia with evidence of bacterial infection. Numbers of granulocytes increase by treating donors with G-CSF and steroids
Blood Storage Blood products Storage Shelf lifeRed cells 2-6 oc 35 daysFrozen red cells 2-6 oc 24 hoursWashed red cells 2-6 oc 6 hoursPlatelet concentrate Room temperature 5 daysFresh frozen plasma -20 to -40 oc 12 monthsCryoprecipitate -20 to -40 oc 12 monthsGranulocyte concentrate Room temperature 24 hours
Types of Blood Transfusion Homologous – from a volunteer donor ; interval between 2 donations of at least 2 months Autologous – pre-operative collection & re-infusion on requirement. - possible if Hb > 11g%; No infection; Fit for anesthesia.
Autologous transfusion1. Pre-operative donation2. Isovolemic haemodilution3. Cell salvagePre-operative donation - blood withdrawn pre-operatively & stored for up to 35-42 days. - up to 5 units of patient’s own blood made available, with the last unit being collected 48-72 hours before surgery.
Isovolemic haemodilution - restricted to patients anticipated with significant blood loss (>1000ml). - up to 1.5L of blood withdrawn + standard anticoagulant replaced by saline to maintain blood volume. - fall in Hct reduces the loss of RBCs - withdrawn blood re-infused either during or after surgery.
Cell salvage - blood collected from the operation site either directly during surgery or by the use of collection devices attached to surgical drains. - during surgery, blood collected by suction processed by a cell salvage machine (anticoagulated + washed to remove clots & debris) returned to patient - post-operative drainage returned to patient, most commonly not washed.