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• 1. Contraction of vessel wall, vascular response
• 2. Platelet aggregation - unstable clot
• 3. Initiation of clotting cascade - stable fibrin clot

• 1. Where bleeding is profuse at the site of operation. Therefore PROLONGED bleeding, but clotting may be normal.
• 2. Where bleeding stops for a short time after op, but persistent haemorrhage occurs later owing to failure of the blood to clot. Therefore bleeding time may be normal, but there is an abnormality in coagulation.

• Trauma
• Infection
• Local vascular lesion (eg. haemangioma)

Excessive trauma causes ST bleeding and may also damage blood vessels.

• Bacteria can break down the clot.
• Loose pieces of bone or retained tooth fragments also favour secondary infection.

• 1. Platelet disorders
• 2. Vessel disorders
• 3. Coagulation disorders

• Bruising of skin
• Bleeding from mucosal membranes
• Petechiae

• Bleeding into joints (haemarthroses)
• Muscle haematomas

• Decrease in platelet NUMBER
• Decrease in platelet FUNCTION

• -Thrombocytopenia (idiopathic, drugs, leukaemia, autoimmune)
• - hypersplenism
• -DIC

Disseminated intravascular coagulation. Small clots throughout body consume platelets available for clotting.

• Aspirin
• Clopidogrel
• Von Willebrands disease

• Arterial circulation, where anticoagulants have little effect.
• They may double bleeding time, but minimal affect on coag.

Patients with established cardiovascular or cerebrovascular disease

• Inhibit platelet aggregation to blood vessel wall.
• Irreversible, lasting for the life of the platelet.
• 7-10 days

• Used as an adjunct to anticoag, or in pts with stroke and TIAs
• Reversible effect on enzyme in platelets and vessel cell walls.

• Hereditary disease. VWF helps attract platelets, and binds with factor 8 to prevent its clearance away from site.
• Decrease level of von Willebrand factor +/- factor 8
• DDAVP can be given to raise the level of VWF, but does not work in all types of the disease.
• Factor 8 is also given in haemorrhage cases.

• Hereditary hemorrhagic telangiectasia
• Inherited condition
• Abnormal blood vessels which are delicate, prone to bleeding.

• Inherited: Haemophilia A, B, VW disease
• Acquired: Liver disease, biliary disease, DIC, drugs - warfarin

Factor 8

• Mild - 5-40% (DDAVP will do in these cases)
• Moderate - 2-5%
• Severe - 0-1%

• Desmopressin, a synthetic substance with an action similar to vasopressin.
• Increases renal water absorption, and at high concs increases level of factor 8 and VWF.
• Subcutaneously or intranasal spray.

• No regional blocks, or injections in FOM or IM. Factor 8 cover must be given.
• AB cover can protect clot from breaking down.

9. Factor 9 has a longer half life, so can be given daily.

An antifibrinolytic drug. Available as a mouth wash.

• Vit K deficiency
• Reduced synthesis of clotting factors
• Funtional abnormalities of platelets

• Vit K
• tranexamic acid
• FFP

• FBC - Platelet count
• Blood film - Morphology of cells
• Coagulation screen - aPPT and PT measures if clotting factors are working properly.

• Abnormalities of factors 7, 10, 5, 2, 1
• Liver disease
• Pts on Warfarin

• Decreased factor 8
• PT normal
• aPTT prolonged

Venous. Slow-moving, thrombus is made from a Fibrin web emeshed with platelets and RBCs.

• 2, 7, 9, 10
• Therefore treatment with Vit K, Fresh frozen plasma

• Prophylaxis/prevent DVT
• Recent MI 3/12
• Established DVT 3/12
• PE 3-6/12
• Xenograft cardiac valves 3/12

• Recurrent venous thromboembolism
• Rheumatic heart disease
• Atrial Fibrillation
• Prosthetic heart valves

• Metronidazole
• Fluconazole, itraconazole, miconazole -- very serious!!
• Alcohol
• NSAIDs (caution increased GI bleeds)

• Barbiturates
• Erythromycin? - unpredictable.

• Ratio of patient's PT to a normal reference
• Normal - 1

• Below 4.0 for atraumatic removal of upto 3 teeth. Suture and pack.
• MOS and multiple extractions below 3.0