Bleeding Time & Clotting Time

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Bleeding Time & Clotting Time

  1. 1. Aim ; Estimation of Bleeding Time (B.T) & Clotting Time (C.T) with Discussion. Dr. Laxmikanta Say
  2. 2. What is the clinical significance of doing BT & CT ?  1. History of frequent, persistent or spontaneous bleeding  2.Before every minor and major surgery -(e.g. tooth extraction)  3.Before taking biopsy -( bone marrow, liver, kidney etc.)  4.Before and during anticoagulant therapy  5.Family history of bleeding disorder 2
  3. 3. BLEEDING TIME (B.T)  Definition ; - time interval between the skin puncture and spontaneous , unassisted stoppage of bleeding.  Method ; “Duke’s method”,  Other methods ; “ivy” Bleeding time  Apparatus Required ; - sterile finger prick, clean filter paper, stop watch.  Procedure;  Precautions;  Normal bleeding time ; 1 – 5 min. 3
  4. 4. CLOTTING TIME ( C.T )  Definition ; - time interval between entry of blood into glass capillary tube, or a syringe, and formation of fibrin threads.  Method ; Wright’s capillary glass tube  Other Methods ; Duke’s Drop method, Lee and White test-tube method  Apparatus Required ; - 10-12 cm long, glass capillary tube with uniform diameter, stop watch  Procedure ;  Normal Clotting Time ; 3 – 6 min. 4
  5. 5. PROTHROMBIN TIME (P.T)  Normal P.T ; 15 – 20 sec.  Clinical Significance ; bleeding tendency occurs below 20% (Normal plasma prothrombin = 30- 40 mg/dl)  Low prothrombin suggest Vit. K def. and liver and biliary diseases.  Prolonged suggests deficiency of factor II, V, VII, and X. 5
  6. 6. DISCUSSION 6
  7. 7. WHAT IS HOMEOSTASIS ? “milieu interieur” Maintenance of nearly constant conditions in the internal environment. 7
  8. 8. WHAT IS HEMOSTASIS ? Haema = blood Stasis = to halt The process of stoppage of bleeding.  It is the process of forming clots in the wall of damaged blood vessels & preventing blood loss while maintaining blood in a fluid state with in the vascular system. 8
  9. 9. What are the stages of Hemostasis ? 1. Vasoconstriction ( contraction of injured blood vessels ) 2.Platelet plug formation 3.Formation of blood clot 4.Fibinolysis ( dissolution of the clot ) 9
  10. 10. Factors responsible for Contraction of blood vessels ! 1. Mechanical stimulation of smooth muscle fibers 2.Local reflexes by stimulation of pain and sensory fibers. 3.Release of potent vasoconstrictors from platelets - serotonin, epinephrine, thromboxane A2 , prostaglandins, endothelins. 10
  11. 11. Platelet plug formation: platelet adhesion
  12. 12. Platelet plug formation: platelet release action
  13. 13. Platelet plug formation: platelet aggregation
  14. 14. Clotting Factors Factor I Fibrinogen Factor II Prothrombin Factor III Thromboplastin Factor IV Calcium Factor V Labile factor, or proaccelerin Factor VI Non – existent Factor VII Stable factor or proconvertin Factor VIII Antihaemophilic Factor IX Christmas factor or Antihaemophilic factor B Factor X Stuart – Prower factor Factor XI Plasma thromboplastin antecedent or Antihaemophilic factor C Factor XII Hageman factor or Contact factor Factor XIII Fibrin stabilizing factor or Laki – Lorand factor factor / globulin A 14
  15. 15. Mechanism of blood Coagulation 15
  16. 16. Why blood does not clot in circulation ? 1.Endothelial surface factor -smoothness -layer of glycocalyx -Negatively charged 2.Velocity of circulation 3.Natural anticoagulants 4.Activation of Fibrinolytic system 5.Liver removes activated clotting factors
  17. 17. Bleeding Disorders 17
  18. 18. Name the conditions where bleeding time is prolonged and clotting time is normal ?  1. Low platelet count  2.Functional platelet defect ; i.Drugs : aspirin, large dose of penicilin ii.von Willebrand disease iii.others : uremia, cirrohosis, leukemia  3. Vessel wall defects ; i. Prolonged corticosteroid trt. ii. Allergic purpura iii. Infections : typhus, bacterial endocarditis iv. Deficiency of Vit – C v.Connective tissue diseases 18
  19. 19. Name the conditions where clotting time is prolonged and bleeding time is normal ?  1. Hereditary coagulation disorders i. Hemophilias ii. von Willebrand disease iii. Afibrinogenemia or dysfibrinogenemia  2. Acquired Coagulation disorders i. Vit – K def. ii. Liver disease iii. Intravascular clotting iv. Anticoagulant therapy  3. Newborns 19
  20. 20. Vit-K dependent factors Factor - II, VII, IX, X 20
  21. 21. Cofactors HMW Kininogen ,F-V, F-VIII, Protein-S, Tissue factor, Platelet lipid 21
  22. 22. Inhibitors Protein-C, Antithrombin-III,Extrinsic Pathway Inhibitor 22
  23. 23. Hemophilia – A (Classic Hemophilia) Factor VIII deficiency 23
  24. 24. Hemophilia – B ( Christmas disease) Factor – IX deficiency 24
  25. 25. Hemophilia - C Factor – XI ( Plasma thrombo plastin anticedent ) deficiency. 25
  26. 26. Hemophilia - D Factor – XII ( Hageman factor) deficiency 26
  27. 27. Purpura Definition - purple coloured petichial hemorrhages and bruises in the skin. - blood leaks out from capillaries Causes - thrombocytopenia, functional platelet defects, allergy, old age 27
  28. 28. Types  Pathologic I. Primary – idiopathic , ITP (antibody formation) II. Secondary – Drugs, chemicals, bone marrow depression, excess destruction, hypersplenism  Forms or Classification 1. Thrombocytopenic Purpura 2. Athrombocytopenic Purpura 3. Thromboasthenic Purpura 4. Haemorrhagic Telangiectasis 28
  29. 29. THANK YOU 29
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