Local hemostatic agents(2)

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Local hemostatic agents(2)

  1. 1. Surgical Secondary Hemostasis in Wound Healing Dr. Milan D Choksey
  2. 2. "An area of increasing concern is lethal hemorrhage from sites that are not suitable for application of tourniquets or compression dressings." Hasan B. Alam. "Hemorrhage control in the battlefield: Role of new hemostatic agents." Military Medicine, 170(1):63-69.
  3. 3. Hemostasis
  4. 4. Biology of Hemostasis Injury to a vessel Platelet factors Platelet plug Vascular factors Vasoconstriction Plasma/blood factors Fibrin clot Stable Hemostatic clot Synergy of Factors contributing to normal hemostasis
  5. 5. Phases of Hemostasis • Primary hemostasis – Arteriolar vasoconstriction – Formation of platelet plug • Secondary hemostasis – Activation of coagulation cascade – Formation of permanent fibrin plug
  6. 6. Types of bleeding during Surgery • Arterial bleeding: – Pulsating • Venous bleeding – Oozes Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  7. 7. Factors influencing Surgical bleeding Type of procedure Patient position Surgical incisions Exposed bone Large surfaces of exposed capillaries • Unseen sources of bleeding • Tissues that cannot be sutured or low-pressure suture lines • Adhesions stripped during surgery • Specific anatomical considerations • Medications (eg. Anticoagulants) • Coagulopathies Procedural factors Patient factors • • • • • • Platelet dysfunction or deficiency • Fibrinolytic activity • Coagulation factor deficiencies • Medical conditions • Nutritional status Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  8. 8. Adverse effects of Surgical bleeding • • • • • • Visual obstruction of the surgical field Need for blood transfusions Reduction in core temperature Thrombocytopenia Hypovolemic shock Economic consequences Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  9. 9. Characteristics of an Ideal hemostatic agents for prehospital/battlefield use: (1) capability to stop large vessel arterial and venous bleeding within minutes of application when applied to an actively bleeding wound through a pool of blood; (2) no requirement for mixing or pre-application preparation; (3) simplicity of application by wounded victim, buddy, or medic; (4) light weight and durable; (5) long shelf life in extreme environments; (6) safe to use with no risk of injury to tissues or transmission of infection; (7) cost-effective
  10. 10. Methods of Hemostasis Mechanical methods . Direct pressure . Fabric pads/sponges/gauzes . Sutures/staples/ligating clips Thermal/energy based methods . Electrosurgery . Monopolar . Bipolar . Bipolar vessel sealing device . Argon enhanced coagulation . Ultrasonic device . Laser Chemical methods . Pharmacological agents . Epinephrine . Vitamin K . Protamine . Desmopressin . Lysine analogues . rFVIIa Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  11. 11. . Topical hemostatic agents . Passive (mechanical) agents . Active agents . Others . Collagen based agents . Cellulose . Gelatin . Polysaccharide spheres . Thrombin products . Flowables . Sealants . Fibrin sealants . Polyethylene glycol (PEG) polymers . Albumin and glutaraldehyde . Cyano-acrylate Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  12. 12. Mechanical methods Direct pressure • Simplest & fastest • Surgeon’s first choice • Arterial bleeding better controlled than venous Fabric pads/gauzes/sponges • Application of direct pressure • Packaging of body cavity • No. of sponges used during surgery needs to be counted • Temporary measures Sutures/staples/ligating clips • Sutures and ties used as ligatures to tie off blood vessels • Chances of FB reaction, tissue reaction, injury & allergic reactions • For staples, stapling device required • Efficient method when diving tissue • Ligating clips – quick & easy to apply • Applicator required • Site of application should be clearly visible Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  13. 13. Thermal/energy based methods Electro-surgery • Use of high frequency (radio) alternating current for cutting, coagulating and vaporizing tissues • Potential risks – patient injuries, user injuries, fires & electromagnetic interference • Monopolar – most frequently used • Bipolar – better on delicate tissues/small anatomical structures • Bipolar vessel sealing device – applies heat with high compression. Capable of simultaneously sealing and transecting vessels upto 7 mm diameter, large tissue pedicles, vascular bundles • Argon enhanced coagulation technology Ultrasonic devices • Converts electrical energy to mechanical energy • Simultaneously cuts & coagulates • Less thermal damage to tissues Lasers • Laser energy delivered to target site can be reflected, scattered, transmitted or absorbed Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  14. 14. Monopolar Electrosurgical Unit Bipolar Electrosurgical Unit Bipolar Vessel Sealing device
  15. 15. Chemical methods – pharmacological agents Chemical agents enhance the natural coagulative mechanisms Epinephrine • Causes direct vasoconstriction & increases heart rate • Can be applied topically or injected with local anesthesia Vitamin K • Administered pre-operatively to reverse effects of warfarin & to avoid need of transfusion of FFP • Reversal of raised INR takes app. 24 hours Protamine • Only agent with ability to reverse heparin anticoagulation • Can cause anaphylaxis, acute pulmonary vasoconstriction, right ventricular failure
  16. 16. Desmopressin • Stimulates release of von Willebrand factor (vWF) & enhances primary hemostasis Lysine analogues • Aminocaproic acid, tranexamic acid • Are antifibrinolytic and competitively inhibit activation of plasminogen • Variable effect & published data is limited Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  17. 17. Historical background of Chemical hemostatic agents • Hippocrates used caustics to achieve hemostasis. • At the end of the eighteenth century, Carnot introduced gelatin. • In 1886 Horsley developed a mixture of beeswax, salicylic acid, and almond oil, thus leaving his legacy of “antiseptic wax.” • Oxidized cellulose(OC) in 1942 • Oxidized Regenerated Cellulose (ORC) was developed in 1960 • Gelatin foam(GF) in 1945 • Microfibrillar collagen (MFC) was developed in 1970 by Hait • Chitosan based agents was approved by FDA at 2003 • The newest mineral based agent has been introduced by US Army Institute of Surgical Research in 2007 • A Plant extract agents was registered in Turkey in 2007
  18. 18. Topical hemostatic agents • Two primary categories: passive and active Passive Act passively thru contact with bleeding sites and promotion of platelet aggregation Active Acts biologically on the clotting cascade Eg collagens, cellulose, gelatins and Eg thrombin and products in which polysacchride spheres thrombin is combined with a passive agent • Two more categories: flowables & sealants Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  19. 19. Topical agents – passive Provides a physical, lattice like matrix that adheres to bleeding site Matrix activates the extrinsic clotting pathway Platelets aggregate and form a clot Passive agents rely on fibrin production and hence can be used only in a patient with intact coagulation cascade Passive agents can absorb several times its weight in fluid. However, this expansion of the agent can cause complications like compression of surrounding tissues. Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  20. 20. Collagen based products Activated on contact with bleeding. Provide stable matrix for clot formation, enhance platelet aggregation, degranulation and release of clotting factors Derived from either bovine tendon or bovine dermal collagen Microfibrillar collagen hemostat • Derived from purified bovine dermal collagen • Effective agents when there is capillary, venous or small arterial bleeding • Potential adverse events: allergic reaction, adhesion formation, inflammation, FB reaction, potentiation of infection and abscess formation Absorbable collagen hemostat sponge • Derived from purified and lyophilized bovine flexor tendon • Collagen sponge gets absorbed into 8 to 10 weeks Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  21. 21. Oxidized regenerated cellulose • ORC reacts with blood, increases in size and forms a gelatinous mass and promotes clot formation • Potential AEs: encapsulation of fluid and FB reaction, stenosis of vascular structures, burning or stinging sensations, headaches , etc Gelatins • Derived from purified bovine gelatin solutions • Can be used in dry or wet form • Conforms easily to wounds and therefore can be used for irregular wounds Polysacchride hemospheres • Derived from vegetable starch • Contains no human or animal component Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  22. 22. Topical agents – active Have biological activity Participate directly at the end of coagulation cascade Stimulate fibrinogen at the bleeding site to produce a clot Thrombin acts at the end of the clotting cascade, action of agent is not affected by clotting factor deficiencies or platelets malfunction. Can also be given to patients receiving anti-platelets/anti-coagulation Active topical agents provide hemostasis within 10 minutes and they are more effective in controlling bleeding than passive agents Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  23. 23. Thrombin products Bovine thrombin • Applied using a pump or spray kit, or in a saturated, absorbable gelatin sponge • AEs: antibody formation to bovine thrombin can lead to coagulopathy, allergic reactions, death Pooled human plasma thrombin • Delivered via saturated, absorbable gelatin sponge • Has potential risk of viral or prion disease transmission Recombinant thrombin • Reduced risk of antibody formation and eliminates risk of viral or prion disease transmission Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  24. 24. Flowable hemostatic agents • Combine passive and active hemostatic agents into a single application product • Work by blocking blood flow & actively converting fibrinogen into fibrin • Two types of products: – Absorbable bovine gelatin + pooled human thrombin – Absorbable porcine gelatin + either of the 3 thrombin types • Both the products do not contain fibrinogen. Hence direct contact with blood is necessary • Both products are indicated for all types of surgeries except ophthalmic surgeries • AEs: anemia, arrhythmia, arterial thrombosis, atelectasis, atrial fibrillation, hemorrhage, infection, pleural effusion, right heart failure Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  25. 25. Sealants Sealants work by forming a barrier that is impervious to the flow of most liquids Fibrin sealants • Consists of conc fibrinogen and thrombin which upon mixing with blood create a fibrin clot • Increases rate of clot formation by providing higher conc of both fibrinogen & thrombin at bleeding site • 3 types: pooled human plasma, individual human plasma with bovine collagen and bovine thrombin, pooled human plasma and equine collagen • Fibrin sealants control local as well as diffuse bleeding • Do not control vigorous bleeding • Fibrin sealants can be used in patients with coagulopathies • Also in patients receiving heparin • Clinical concerns: difficulty of reconstitution, time taken for surgeon to learn application • AEs: viral or prion disease transmission, antibody formation with bovine thrombin, swelling associated with collagen use Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  26. 26. Polyethylene glycol polymers Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  27. 27. Albumin-glutaraldehyde • Contains 10% glutaraldehyde sol and 45% bovine serum albumin • Glutaraldehyde cross-links the residual proteins in albumin to cell proteins at wound site and forms a tough scaffold to which clot can adhere • Commonly used for sealing holes around suture or staple lines in complex CV procedures and in peripheral vascular procedures • AEs: tissue injury, muscle necrosis, emboli, delayed pseudoaneurysm formation, sensitivity to glutaraldehyde Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  28. 28. Cyano-acrylates • Consists of 2 cyanoacrylate monomers – 2-octyl cyanoacrylate – Butyl lactoyl cyanoacrylate • Product to be used as a sealant and not as a substitute for sutures, staples, or other methods of mechanical closure Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  29. 29. Key considerations in the selection of topical agent • • • • • • • • • Rapidly and effectively control bleeding Effectively contact the bleeding surface Work reliably Be handled easily Be prepared easily Be available in multiple delivery options Be compatible with patient’s physiology Be safely used Be cost effective Adapted with permission from: Samudrala S. Topical hemostatic agents in surgery: a surgeon’s perspective. AORN J. 2008;88(3): S2-S11
  30. 30. Thank you

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