Hemostasis and coagulation for medical .pptx

hemostasis, Surgical bleeding & Transfusion

1. SALALE UNIVERSITY COLLEGE OF HEALTH SCIENCES SCHOOL OF MEDICINE SURGERY CLERKSHIP –I ( SURG 4011 ) LECTURE FOR CLINICAL- I STUDENTS DEPARTMENT OF SURGERY 10/20/2024

2. HEMOSTASIS, SURGICAL BLEEDING & TRANSFUSION Dr. Kasahun G. (MD, Asst. Prof of Surgery ) 10/20/2024

3. OUTLINE OF PRESENTATION Objectives Biology of Hemostasis Tests for Hemostasis & Coagulation Coagulation disorders Evaluation of excessive intra or post op bleeding Transfusion 10/20/2024

4. OBJECTIVES At the end of this lecture the students Will be able to:- Define hemostasis & State the Mechanism Describe Tests for Hemostasis & Coagulation Common Disorders of Hemostasis & Coagulation Evaluation of excessive intra or post op bleeding Indication, Contraindication & Complication of Blood Transfusion 10/20/2024

5. BIOLOGY OF HEMOSTASIS 10/20/2024

6. Definition Hemostasis is the prevention of blood loss by arresting of bleeding from injured vessels 10/20/2024

7. BIOLOGY OF HEMOSTASIS C omplex process whose function is to limit blood loss from an injured vessel Four major physiologic events participate in the hemostatic process: V ascular constriction, P latelet plug formation, F ibrin formation (Coagulation), Fibrinolysis . Although each tends to be activated in order, they are interrelated so that there is a continuum and multiple reinforcements. 10/20/2024

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9. BIOLOGY …. 1. Vascular Constriction I nitial response to vessel injury. M ore pronounced in vessels with medial smooth muscles D ependent on local contraction of smooth muscle. S ubsequently linked to platelet plug formation. MEDIATORS Thromboxane A2 ( TXA2) Endothelin S erotonin (5-hydroxytryptamine [5-HT]) B radykinin and F ibrinopeptides , The extent varies with the degree of vessel injury. 10/20/2024

10. BIOLOGY …. 2. Platelet Plug formation Platelets Anucleate fragments of megakaryocytes. 150,000 and 400,000/ μL . Up to 30% of may be sequestered in the spleen A verage life span of 7 to 10 days. Form a hemostatic plug and contribute to thrombin formation Do not normally adhere to each other or to the vessel wall but can form a plug that aids in cessation of bleeding when vascular disruption occurs . 10/20/2024

11. BIOLOGY …. 2. Platelet Plug formation Platelet aggregation results from the release of platelet factors and fibrin. Leads to formation of a platelet plug that acts as a physical barrier to further bleeding. 10/20/2024

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13. BIOLOGY …. 3 . Coagulation C omplex interplay and combination of interactions b/n Platelets, The endothelium, and C irculating or membrane-bound coagulation factors D ivided into the initiation, amplification, and propagation phases 10/20/2024

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15. BIOLOGY …. 4. Fibrinolysis A llows restoration of blood flow during the healing Begins at the same time clot formation is initiated D irected by circulating kinases, tissue activators , and kallikrein present in vascular endothelium 10/20/2024

16. BLEEDING DISORDER A. CONGENITAL 10/20/2024

17. Hemophilia Hemophilia A (von Willebrand’s disease):- Factor VIII deficiency Hemophilia B (Christmas disease ): - Factor IX deficiency Inherited as sex-linked recessive disorders, M ales affected almost exclusively . C linical severity depends on the measurable level of factors in the plasma Severe disease ( ≤ 1% of normal ) :- spontaneous bleeding Moderately severe disease ( 1 % - 5 % ):- less spontaneous bleeding but are likely to bleed severely after trauma or surgery Mild disease ( 5% - 30 %): - have only minor bleeding after major trauma or surgery H emophilia A or B are treated with factorVIII or factor IX concentrate, respectively 10/20/2024

18. von Willebrand’s Disease T he most common congenital bleeding disorder, Characterized by a quantitative or qualitative defect in vWF , Patients Will have easy bruising and mucosal bleeding. Menorrhagia is common in women. (like platelet disorder) Type I: - partial quantitative deficiency; (respond well to desmopressin ( DDAVP)) T ype II: - qualitative defect; (may respond, depending on the particular defect) T ype III: - is total deficiency; (usually unresponsive .) may require vWF concentrates . 10/20/2024

19. BLEEDING DISORDER B. AQUIRED 10/20/2024

20. Platelet Abnormalities 10/20/2024

21. Disseminated Intravascular Coagulation (DIC). C haracterized by systemic activation of coagulation pathways that result in excessive thrombin generation and the diffuse formation of microthrombi The diagnosis is made based on an inciting etiology with associated thrombocytopenia , prolongation of the prothrombin time, a low fibrinogen level, and elevated fibrin markers (FDPs, D-dimer, soluble fibrin monomers). Treatment P rimary medical or surgical problem ( most important) M aintaining adequate perfusion. If there is active bleeding, hemostatic factors should be replaced with FFP, (cryoprecipitate , fibrinogen concentrates, or platelet concentrates may also be needed ) Heparin may be indicated in cases where thrombosis predominates , 10/20/2024

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24. Coagulopathy of trauma 10/20/2024

25. Anticlotting and Thrombolytic Drugs Agents that depress the action of procoagulants Aspirin – platelet cyclooxygenase inhibitor. Oral anticoagulants ( Dicumarol ) – inhibits action of vitamin K required for synthesis of clotting factors by the liver. Heparin – activates antithrombin III. Fibrinogen blockers - interfere with fibrinogen binding to platelets. Agents that dissolve clots (thrombolytic drugs) Recombinant t-PA Desmodus rotundus salivary plasmninogen activator (DSPA) Streptokinase

26. Testing the Surgical Patient for Hemostatic Risk Factors For minor surgical procedures , Hx & P/E is enough PT, PTT, Bleeding Time :- major surgical procedure (one that involves a large part of the body), or the operation is to involve a part of the body where even a small amount of excessive bleeding would have disastrous complications (that is, involving the eye or brain ) 10/20/2024

27. Hemostatic Tests PROTHROMBIN TIME (PT) :- measures the function of factors I, II, V, VII, and X B est suited to detect abnormal coagulation caused by vitamin K deficiencies and warfarin therapy . Activated Partial Thromboplastin Time ( aPTT ): - measures function of factors I, II , and V of the common pathway and factors VIII, IX, X, and XII of the intrinsic pathway. Heparin therapy is often monitored by following aPTT values with a therapeutic target range of 1.5 to 2.5 times the control value PLATELET COUNT:- Hemorrhage expected if, < 50,000/ μL - with major surgical procedures < 30,000/ μL ,- with minor surgical procedures < 20,000/ μL - spontaneous hemorrhage 10/20/2024

28. HAEMORRHAGE M ust be recognised and managed aggressively to reduce the severity and duration of shock and avoid death and/or multiple organ failure. T reated by arresting the bleeding – not by fluid resuscitation or blood transfusion . Revealed haemorrhage :- obvious external haemorrhage , like open arterial wound or from massive haematemesis from a duodenal ulcer. Concealed haemorrhage is contained within the body cavity and must be suspected, actively investigated and controlled. 10/20/2024

29. HAEMORRHAGE Primary haemorrhage :- occur immediately due to an injury (or surgery). Reactionary haemorrhage :- delayed haemorrhage (within 24 hours) Usually due to dislodgement of a clot by resuscitation, normalisation of BP and vasodilatation. May also be due to technical failure, such as slippage of a ligature. Secondary haemorrhage is due to sloughing of the wall of a vessel. Usually occurs 7–14 days after injury Precipitated by factors such as infection, pressure necrosis (such as from a drain) or malignancy . 10/20/2024

30. MANAGEMENT OF HAEMORRHAGE Local measures — Pressure application D igital pressure P acking B alloon tamponade . Elevation of limb. Mechanical H emostatic forceps, vascular clamps. L igature . Harmonic scalpel Thermal :- Heat causes denaturation of protein that results in coagulum formation 10/20/2024

31. TRANSFUSION of BLOOD AND ITS COMPONENTS 10/20/2024

32. History of blood transfusion . 1492 Pope Innocent VIII suffers a stroke and receives a blood transfusion from three 10-year-old boys (paid a ducat each). All three boys died, as did the pope later that year 1665 Richard Lower in Oxford conducts the first successful canine transfusions 1667 Jean-Baptiste Denis reports successful sheep–human transfusions 1678 Animal–human transfusions are banned in France because of the poor results 1818 James Blundell performs the first successful documented human transfusion in a woman suffering post-partum haemorrhage . She received blood from her husband and survived 1901 Karl Landsteiner discovers the ABO system 1914 The Belgian physician Albert Hustin performed the first non-direct transfusion, using sodium citrate as an anticoagulant 1926 The British Red Cross instituted the first blood transfusion service in the world 1939 The Rhesus system was identified and recognised as the major cause of transfusion reactions 10/20/2024

33. Indications Acute blood loss: - to replace circulating volume and maintain oxygen delivery; Perioperative anaemia :- to ensure adequate oxygen delivery during the perioperative phase; Symptomatic chronic anaemia :- without haemorrhage or impending surgery. Replacement of clotting factors —In hemorrhagic disorders (e.g. hemophilia, Christmas disease) 10/20/2024

34. Whole Blood and Its Fractions Whole blood — Stored ( 4°C ± 2°C), The shelf life is 3 weeks Ideal component for patients having acute hemorrhage amounting ≥ 25 % of TV Packed RBC —prepared by certifugation . & Indicated in pediatric patients & In elderly, patient with chronic anemia. Platelet concentrates — Indicated in both qualitative and quantitative platelet disorders. Prepared either as random donor (RD) platelets or single donor apheresis platelets stored on a special agitator at 20–24°C and have a shelf life of only 5 days 10/20/2024

35. Whole Blood and Its Fractions Fresh-frozen plasma — stored at -40 to -50°C with a 2­year shelf life. source of vitamin K- dependant factors and the only source of factor V. Indicated in congenital hemorhagic disorders, TTP, patient with liver failure. Cryoprecipitate — a source of fibrinogen, factor VIII, von Willebrand factor . Is an alternative to factor VIII concentrate. It is stored at -30°C with a 2 ­ year shelf life 10/20/2024

36. Complications of Transfusion Incompatibility haemolytic transfusion reaction; Febrile transfusion reaction; Allergic reaction; Infection: Bacterial infection (usually due to faulty storage); Hepatitis; HIV; Malaria; Air embolism; Thrombophlebitis; Transfusion ­related acute lung injury (usually from FFP) From single transfusion 10/20/2024

37. Complications of Transfusion From massive transfusion Coagulopathy; Hypocalcaemia; Hyperkalaemia ; Hypokalaemia ; Hypothermia 10/20/2024

38. References Schwartz’s Principles Of Surgery Eleventh Edition Bailey & Love’s Short Practice of Surgery 28 th Edition Up to date 2024 Medscape 10/20/2024

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