Pharmacology Chapter 9 ST

Coagulants

Promote clotting

Anticoagulants

Inhibit clotting

What happens when damage occurs to blood vessels?

The body's coagulation mechanism begins clot formation to prevent excessive blood loss.

How are damaged blood vessels controlled intraoperatively?

With the use of thermal hemostasis or mechanical hemostasis

What are topical hemostatics?

Coagulants used on areas of capillary bleeding as an adjunct to natural hemostasis

Systemic anticoagulants are used to prevent or delay the onset of what?

The coagulation sequence during surgical procedures used on blood vessels.

What is a thrombus?

Blood clot

What are thrombolytics?

Used to speed up clot breakdown.

Stage 1 of clot formation

Thromboplastin is formed

Stage 2 of clot formation

Thromboplastin converts prothrombin into thrombin

Stage 3 of clot formation

Thrombin converts fibrinogen

Two pathways used in Stage 1 of clot formation

Extrinsic and Intrinsic

The extrinsic pathway is initiated by what?

Factors outside the blood

The intrinsic pathway is initiated by what?

Substances contained in the blood

What is required at all stages of clot formation?

Calcium

What is clotting that takes place within an unbroken blood vessel?

Thrombosis

Two major categories of coagulants

hemostatics and systemic coagulants

What are hemostatics?

Agents that enhance or accelerate blood clotting at a surgical site.

How can hemostatics be applied topically?

In the form of films, powder, sponges, or solutions.

What are absorbable gelatin hemostatics made from?

Animal in origin, made from purified porcine skin gelatin USP

Are absorbable gelatin hemostatics mechanical or chemical in action?

Mechanical

How long does it take for absorbable gelatin hemostatics to absorb?

Absorbed completely in 4-6 weeks

When can absorbable gelatins not be used?

in the presence of infection

Where should absorbable gelatins never be placed?

intravascularly

Examples of gelatin hemostatics

Gelfilm as well as Gelfoam powder and sponges and Surgifoam

What are absorbable collagen sponges made from?

Purified bovine collagen

What do absorbable collagen sponges promote when applied to bleeding surfaces?

Platelet aggregation

absorbable collagen sponges should not be applied prior to placement of what?

Methyl Methacrylate (bone cement)

Examples of absorbable collagen sponges

Collastat, Helistat, Hemopad, and Instat

What are the two types of microfibrillar collagen hemostats?

Avitene MCH and Instat MCH

What is Avitene MCH?

Dry, fibrous preparation of purified bovine corium collagen

Avitene MCH causes a formation of what when applied directly to bleeding surfaces?

Fibrin clot

Avitene MCH should be applied with what and why?

Dry instruments only; because wetting decreases its hemostatic efficiency

What is Instat MCH?

Derived from bovine deep flexor tendon, a source of pure collagen

What is the onset of Instat MCH?

2-4 minutes

Oxidized cellulose swells and becomes what?

a gelatinous mass that serves as a nucleus for clotting

Oxidized regenerated cellulose removal is recommended after what is acheived?

Hemostasis

OCR is available in what?

Knitted gauze strips or fiber form

Examples of OCR

Surgicel gauze, Surgicel Nu-knit and Surgicel Fibrillar

Surgicel absorbable hemostat is what?

Bactericidal and effective against a wide range of gram-positive and gram-negative microorganisms

OCR has a low ____ and should not be used with any agent containing ______ or _____ thrombin.

pH; bovine; human

What is Thrombin?

a topical liquid hemostatic agent of bovine origin

How can thrombin come prepared?

A spray bottle kit or in a powder form that must be reconstituted with sterile water or saline.

When should thrombin be used?

Immediately after preparation, or it should be refrigerated and used immediately after reconstituting.

Thrombin works by catalyzing the conversion of _______ to _____, thus increasing the speed of the natural clotting mechanism.

Fibrinogen; fibrin

Thrombin is measured in what?

Units

Thrombin comes in strengths of what?

1000-20000

Thrombin (bovine) gelatin sponge

Thrombi-Gel

Thrombin (bovine) nonwoven

Thrombi-Pad

Thrombin, topical (human)

Evithrom

Thrombin, topical (recombinant)

Recothrom

Thrombin and microfibrillar collagen

Vitagel

Fibrin sealant

Tisseel and Evicel

Thrombin, topical (human) and gelatin granules

Floseal

What topical hemostatic agent is made from beeswax?

Bone Wax

A hemostatic agent that is made from an astringent plant?

Tannic Acid

What is silver nitrate?

Cauterizing agent, especially when mixed with potassium nitrate.

What is the silver nitrate combination molded onto?

Applicator sticks

A chemical hemostatic agent that is deep brown solution of ferrous sulfate, sulfuric acid, and nitric acid diluted with water?

Monsel Solution

What are the 4 types of systemic coagulants?

Calcium Salts, Vitamin K, Antihemophilic factor, Factor IX complex

Calcium salts can not be given to patients with a history of what?

Malignant Hyperthemia

What is a fat-soluble vitamin that promotes blood clotting by increasing synthesis of coagulation factors?

Vitamin K

Vitamin K is available as ____ for oral administration or as ____ for injection.

Phytonadione (Mephyton); Vitamin K (AquaMEPHYTON)

Factor IX is a concentrate of what?

dried plasma fractions

Anticoagulants are administered in the medical setting to prevent what?

Venous thrombosis, pulmonary embolism, acute coronary occlusions after myocardial infection, and strokes caused by an embolus or cerebral blood clot.

What is the most commonly used parenteral anticoagulant?

Heparin sodium

Heparin acts by binding antithrombin ____, which greatly increases AT III's ability to inhibit the action of coagulation factors thrombin, Xa, and IXa.

III

Heparin is measured in what?

Units

Heparin is available in doses of how many units for injection?

10-10,000 units/mL

Hep-Lock catheter flush heparin is supplied in units of what?

10 & 100

Low-molecular-weight heparins are used to prevent or treat what?

DVT and PE

Fondparinux (Arixtra) is what kind of factor used for post op and long-term prophylaxis of DVT and PE in orthopedic fracture, total joint, and abdominal surgery patients.

Xa factor inhibitor

What kind of anticoagulants are used for long-term medical management of thromboembolic disease such as DVT or PE?

Oral

What are the two main types of oral anticoagulants?

Warfarin (Coumadin) and Aspirin

Coumarin derivatives act by inhibiting what activity in the liver?

Vitamin K

What agents are given intravenously in the medical setting to help dissolve blood clots?

Thrombolytics

Thrombolytics activate _____ to form plasmin, which digests fibrin.

plasminogen

Thrombolytic medications

streptokinase (Streptase), urokinase (Abbokinase,Kinlytic), alteplase (Activase), tenectplase (TNKase)