Hemostatic Agent

What Happens During Hemostasis?

Hemostasis includes the following steps:

• Vascular Spasm or Vasoconstriction
• Platelet formation
• Clot formation/ Blood Coagulation

How Does a Hemostatic Agent Work?

When control of capillary, venous, and arteriolar bleeding by pressure, ligature, and other conventional procedures is ineffective or impractical, hemostatic agents are introduced and work either mechanically or by augmenting the coagulation cascade in order to stop the bleeding. The purpose of a hemostatic agent is to maintain hemostasis of the patient during surgery or trauma.

Why are Hemostatic Agents Used?

Without hemostatic agents, operating times may need to be prolonged and the risk of side effects increases.

• In a 2015 clinical study regarding efficacy of Arista™ AH, it was proven that full hemostasis of first treated lesion within 5 minutes (3 minutes for cardiac procedure) results in a success rate of 94.4%, 78.9%, and 94.3% in general, cardic, and orthopedic procedures.

Hemostatic agents can also help to decrease risk in emergency cases such as trauma. Hemorrhagic shock is the second leading cause of death for civilian trauma patients.

When are Hemostatic Agents Needed?

• Hemostatic agents are often needed in surgical procedures when bleeding cannot necessarily be avoided.
• They are also often needed in emergencies where bleeding needs to be controlled.

What are the Subtypes of Hemostatic Agents

There are three main subtypes of hemostatic agents:

• Caustic: Caustic hemostatic agents work by coagulating proteins leading to tissue necrosis and eschar formation, which strengthens the formation of thrombus and hemostasis.
• Physical: Physical hemostatic agents use a substrate (cellulose, gelatin, starch, collagen) which forms a matrix at bleeding site. Extrinsic coagulation cascade is then activated by the dependent reactions of plasma proteins, calcium ions and blood platelets softening that platelet plug from fibrinogen-to fibrin conversion, thus serving as a platform to form clots.
• Biologic: Biologic hemostatic agents, include topical thrombin and fibrin sealants, which promote hemostasis from the bypass of initial steps of coagulation cascade (extrinsic pathway).
  • Topical thrombin agents are applied with either a syringe or spray and should not be combined with oxidized regenerated cellulose since this acidity may neutralize topical thrombin effectiveness.
  • Fibrin sealants enable fibrin clot to form when applied directly to site of bleeding. It is made of thrombin solution and concentrated human fibrinogen solution.

How you use a hemostat will depend on the type of bleeding. Below are directions for two common types:

Microporous polysaccharide hemispheres (Arista™ AH):

• Blot, wipe, or suction the bleeding tissue. It is important to remove excess blood so that Arista™ AH maybe applied immediately and directly to the site of active bleeding.
• Immediately apply a liberal amount of Arista™ AH at the site of bleeding within the wound, as close to the source of bleeding as possible, completely covering the wound. Deep wounds may require equally deep application of Arista™ AH. To minimize occlusion of the tip, pressure should be applied to deliver Arista™ AH as the applicator enters the wound.
• Quickly apply wound-appropriate, direct pressure over the treated site; use of a non-adhering substrate to apply pressure may prevent adhesion of the formed clot to the surgical glove or other instrumentation. Amount and duration of pressure is wound dependent. For neurological applications, pressure is not recommended and for oozing, pressure may not be necessary. For more profuse bleeding wounds, pressure should be maintained longer.
• If bleeding or oozing continues, remove excess Arista™ AH and reapply.
• If any material (ie, surgical glove, sponge, etc) adheres to the newly formed clot, irrigate the material with saline and carefully remove it from the treated site
• Immediately upon contact with fluid, Arista™ AH will swell to approximately 5 times its original volume. Once Hemostasis is achieved, excess Arista™ AH should be carefully removed by irrigation and aspiration.

Microfibrillar Collagen Hemostat (Aviente™):

AVITENE™ (MCH) must be applied directly to the source of bleeding. Because of its adhesiveness, it may seal over the exit site of deeper hemorrhage and conceal an underlying hematoma as in penetrating liver wounds. When possible, surfaces to be treated should be compressed with dry sponges immediately prior to application of the dry AVITENE™. It is then advantageous to apply pressure over the AVITENE™ with a dry sponge for a period of time which varies with the force and severity of bleeding. A minute may suffice for capillary bleeding (e.g., skin graft donor sites, dermatologic curettage) but three to five or more minutes may be required for brisk bleeding (e.g. splenic tears) or high pressure leaks in major artery suture holes. For control of oozing from cancellous bone, it should be firmly packed into the spongy bone surface. After five to ten minutes, excess MCH may be teased away (see Precautions); this can usually be accomplished with blunt forceps and is facilitated by wetting with sterile 0.9% saline solution and irrigation. If breakthrough bleeding occurs in areas of thin application, additional AVITENE™ may be applied…. In neurosurgical and other procedures the non-woven web may conveniently be used by applying small squares to bleeding areas and then covering the sites with moist cottonoid “patties””. After five to ten minutes excess MCH may be removed by teasing and irrigation.