• CPB activates the fibrinolytic pathways

• Fibrinolysis causes bleeding not only by clot breakdown, but by fibrin degradation products

APROTININ “Trasylol”

• Naturally occurring antifibrinolytic

• Enhances clotting by reducing rate of clot breakdown by inhibiting substances which are involved the fibrinolytic pathway

• Bind to plasmin & plasminogen, blocking the ability of the fibrinolytic enzymes to bind at the lysin residues of fibrinogen

• Like synthetic antifibrinolytics, inhibits plasmin & plasminogen but also inhibits kallikrein [which enhances factor XII activation & may explain prolongation of ACT]

• Inhibits kallikrein & thus attenuates activation of neutrophils during CPB

• Attenuates platelet response to CPB by inhibiting the plasmin effect on platelets

• Like any other foreign protein, may cause anaphylaxis

AMINOCAPROIC ACID “Amicar”

• Synthetic antifibrinolytic

• Enhances clotting by reducing rate of clot breakdown by inhibiting substances which are involved the fibrinolytic pathway

• Inhibits plasmin & plasminogen

• Bind to plasmin & plasminogen, blocking the ability of the fibrinolytic enzymes to bind at the lysin residues of fibrinogen

• Prophylactic administration decreases bleeding after bypass and reduces transfusion of homologous blood products

• Used in haemophiliacs prior to minor surgical procedures, as therapy from bleeding from fibrinolytic therapy, prophylaxis for rebleeding from intracranial aneurysms

• Side effects include arrhythmias, bradycardia, intravascular thrombosis from inhibition of plasminogen activator

• When infused iv: give 5 g over 1/2 hr to avoid hypotension

TRANEXAMIC ACID “Cyclokapron”

• Synthetic antifibrinolytic

• Analogue of aminocaproic acid

• Enhances clotting by reducing rate of clot breakdown by inhibiting substances which are involved the fibrinolytic pathway

• 7-10 times more potent than aminocaproic acid and considerably less toxic

• Used in excessive menstrual blood loss

DESMOPRESSIN “dDAVP”

• An analog of vasopressin

• Increases factor VIII [antihaemophilic factor] activity of patients with mild haemophilia or von Willebrand’s disease

• Can be used to improve platelet function & haemostasis in the presence of renal failure, or factor VIII deficiency, and may also decrease bleeding in normal patients following CPB