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General Principles of

General Principles of. Hemostasis. Kristine Krafts, M.D. Hemostasis is a balancing act!. pro - clotting. anti - clotting. plugs up holes in blood vessels. keeps clotting under control. Pro-Clotting. clot. Pro-Clotting. vessels. platelets. cascade. Pro-Clotting.

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General Principles of

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  1. General Principles of Hemostasis Kristine Krafts, M.D.

  2. Hemostasis is a balancing act! pro-clotting anti-clotting plugs up holes in blood vessels keeps clotting under control

  3. Pro-Clotting clot

  4. Pro-Clotting vessels platelets cascade

  5. Pro-Clotting Blood vessel constricts. • Blood loss decreases • Platelets and factors meet

  6. Pro-Clotting Platelets form a plug. • Proteins are exposed • Platelets adhese • Granules release contents • Platelets aggregate • Phospholipids are exposed

  7. Pro-Clotting Fibrin seals up plug. • Tissue factor is exposed • Cascade begins • Cascade makes fibrin • Fibrin solidifies plug

  8. Intrinsic Extrinsic Coagulation Cascade thrombin exposed TF XII XIIa XI XIa TF VIIa IX IXa VII VIIIa VIII Final common pathway X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  9. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  10. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  11. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  12. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  13. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  14. Where does tissue factor come from? • “Hidden” cells exposed during injury • Microparticles floating in blood • Endothelial cells and monocytes (during inflammation)

  15. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  16. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  17. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  18. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  19. Extrinsic Intrinsic TF VII IX VIII X V thrombin fibrin clot

  20. tissue factor fibrin clot

  21. busy simple distracting riveting sinful sexy

  22. Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  23. SINtrinsic Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin busy clot fibrinogen fibrin distracting sinful

  24. SEXtrinsic Intrinsic Extrinsic thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin simple fibrinogen fibrin riveting sexy clot

  25. SINtrinsic SEXtrinsic TF VII IX VIII X V thrombin fibrin clot

  26. Anti-Clotting clot 1 cascade inhibition

  27. Intrinsic Extrinsic TFPI ATIII protein C thrombin exposed TF XI XIa TF VIIa IX IXa VII VIIIa VIII X Xa Va V prothrombin thrombin clot fibrinogen fibrin

  28. Anti-Clotting clot 1 cascade inhibition • TFPI • ATIII • Proteins C, S 2 clot lysis

  29. Anti-Clotting clot plasminogen plasmin t-PA

  30. Hemostasis Outline • The big picture • Laboratory tests

  31. Platelet Lab Tests Count • Done by particle counter • 150 – 450 x 109/L Morphology • Size • Granulation

  32. Platelets

  33. Normal Platelets

  34. Bleeding Time Why? • Evaluate platelet response to vascular injury • Some platelet disorders have a long bleeding time How? • Inflate blood pressure cuff • Make incision • Time how long it takes to stop bleeding Careful! • Lots of things affect the test! • Some consider the test unreliable.

  35. Coagulation Lab Tests • Draw blood into citrate tube • Spin tube, decant plasma • Add reagents to plasma • Watch for formation of fibrin

  36. Prothrombin Time • Plasma + thromboplastin • Measures extrinsic pathway

  37. SEXtrinsic Intrinsic TF VII IX VIII X V thrombin fibrin clot

  38. Extrinsic Intrinsic TF VII IX VIII X V The PT is increased in: •  VII, X, V, II, I • Coumadin • Heparin • DIC thrombin fibrin clot

  39. When should you order a PT? • Never! • Order an INR instead.

  40. What is an INR? Just a corrected PT.

  41. When should you order an INR? • To assess liver function • To monitor Coumadin therapy • To diagnose DIC* • To assess pre-op status * Disseminated intravascular coagulation

  42. Partial Thromboplastin Time • Plasma + phospholipid • Measures intrinsic pathway • APTT = same thing

  43. SINtrinsic Extrinsic TF VII IX VIII X V thrombin fibrin clot

  44. Extrinsic Intrinsic TF VII IX VIII X V The PTT is increased in: • hemophilia A • hemophilia B • DIC • heparin thrombin fibrin clot

  45. When should you order a PTT? • To investigate a history of abnormal bleeding • To monitor heparin therapy • To diagnose DIC • To assess pre-op status

  46. Fibrin Degradation Product Assay • Measures FDPs (including D-dimers) • VERY sensitive!

  47. Anti-Clotting clot

  48. Thrombin XIII cross-linked fibrin fibrinogen fibrin

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