Introduction
More than 51 million surgical procedures are performed annually. Sometimes an injury can also lead to excessive loss of blood. To ensure timely hemostasis (stopping bleeding from a blood vessel) during surgical procedures and injuries, effective bleeding control is necessary for a good outcome and to prevent complications from excessive blood loss. During the natural process of hemostasis in humans, a thrombotic response occurs with complex interactions between clotting and fibrinolytic factors and platelets and vessel walls to endothelial damage.
Hemostasis has two stages. The primary stage is the cellular stage which begins with endothelial injury. Blood flow is then slowed down by vasoconstriction. Following vasoconstriction, inflammatory effector platelet cells adhere and form loose aggregated plugs containing platelets and fibrinogen. In the secondary stage, the soft plug stabilizes with thrombus formation. Platelets, which maintain vasoconstriction and decreased blood flow through the release of serotonin and thromboxane, facilitate this step. The coagulation cascade converts plasma-soluble fibrinogen to insoluble fibrin by thrombin. At the same time, through the conversion of factor XIII to factor XIIIa, cross-linking of fibrin monomers is initiated to form a stable clot.
What Are the Types and Benefits of Hemostatic Agents?
When surgeons ensure rapid hemostasis, the following benefits are expected:
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Reduced surgery time.
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Reduced need for blood transfusions.
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Improved management of patients receiving anticoagulant therapy.
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Improved overall patient recovery time.
Hemostats, sealants, and adhesives are used to promote hemostasis and offer many advantages in injury and surgery. The importance of hemostasis has accelerated the development of new drugs such as oxidized regenerated cellulose (ORC), porcine gelatin, bovine collagen, polysaccharide spheres, and thrombin. These agents vary widely in their mechanism of action, chemical structure, ease of administration, wet or dry tissue adhesion, immunogenicity, and cost.
Hemostatic agents fall into three main categories:
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Hemostats.
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Sealants.
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Adhesives.
In addition, hemostats are also classified as:
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Mechanical hemostats.
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Active hemostats.
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Fluid hemostats.
What Are Different Types of Hemostats?
Different types of hemostats are explained below:
1. Mechanical: Mechanical agents are considered the most effective for small bleeding, creating a barrier that stops blood flow and a surface that allows blood to clot faster.
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Gelatin: Gelatin, known as a hydrocolloid, is made by partially acid-hydrolyzing porcine-derived collagen. It can be found in sponge and powder form. It can be used alone, but it can also be used in combination with topical thrombin. Gelatin can absorb up to 40 times its weight in blood and swell up to 200 percent of its original size. It is possible to cut dry sponge molds into any size and shape. It should be applied dry or with a single press directly on the bleeding site. Gelatin can be left alone; its absorption time is 4 to 6 weeks.
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Collagen: Collagen hemostatic material is made from cowhide. To provide a matrix for clot formation and increase platelet aggregation, degranulation, and release of clotting factors, they bind tightly to the blood surface, thus further promoting clot formation. It is very effective in patients with low platelet counts and controlling arterial bleeding. It is more expensive than gelatin but stops bleeding in 1 to 5 minutes. It can be easily removed by rinsing and suctioning. It also reduces postoperative bleeding and eliminates the need for repeated applications. It is expected to be reabsorbed in 8 to 10 weeks if left untreated. The main problem with bovine collagen is swelling and allergic reactions. Therefore, use a collagen hemostat on areas where pressure can be applied. Bovine collagen should not be used in patients with hypersensitivity or allergy to bovine-derived materials.
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Oxidized Regenerated Cellulose (ORC): ORC products are made from plant-based alpha-cellulose. They can be in single-layer or multi-layer form, as absorbent knitted fabrics, low or high density. Stored at room temperature, ready to use, it can hold 7 to 10 times the weight of blood. They act in an essential way, resulting in contact and platelet activation. Once absorbed, it forms a gelatinous mass that aids in clotting. ORC hemostats are primarily used to control bleeding in capillaries, veins, and arterioles. They should be applied dry. Their absorption time is 4 to 8 weeks. Due to potential swelling, it is not recommended for use in areas of blockage or bleeding from large arteries.
2. Active: Active hemostatic agents include the thrombin enzyme, which catalyzes the conversion of fibrinogen to fibrin, the final part of blood clotting. The first thrombin used was bovine, but its use is complicated by the production of antibodies that cross-react with human clotting factors. To reduce this risk, human thrombin is used in combination with a gelling sponge. On the other hand, using human thrombin is dangerous as it can lead to the transmission of blood-borne pathogens.
3. Flowable: This category is divided into two types:
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Procrine gelatin products are combined with three thrombins like bovine collagen products packaged with bovine, human or prothrombin, and human plasma thrombin.
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Fluid hemostats are known to be the most effective of the hemostats.
What Are Different Types of Sealants?
Various types of sealants are listed below:
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Fibrin Sealants: Fibrin sealants are made from human or animal blood products that mimic the final part of the clotting cascade during clot formation. The combination of lyophilized coagulation protein (such as fibrinogen) and thrombin are in separate vials. They interact to form a stable clot during use. The preparation and application of fibrin glue are somewhat complicated. Fibrinogen is solubilized in water, while thrombin is solubilized in dilute CaCl2 solutions. The two solutions are then transferred into a double syringe so that both solutions can be easily combined during application. Some sealants include two additional components: Human blood factor XIII and aprotinin inhibit enzymes that damage clots.
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Synthetic Sealant: Synthetic sealants contain polyethylene glycol (PEG) polymers and at least one additional ingredient. These agents are known as biodegradable agents that act as both fluid barriers and hemostatic agents. They quickly establish adherent bonds and degrade in 1 to 6 weeks. Synthetic sealants are more expensive than other hemostatic agents.
What Are Different Types of Adhesives?
Adhesive hemostatic agents are mainly used in cardiovascular surgery as a part of routine hemostatic measures. Various types of adhesives are listed below:
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Cyanoacrylate: Most adhesives require evaporation of water, but cyanoacrylates require a small amount of water to affect adhesion. Until recently, it was used topically because its application to surfaces other than the skin causes severe inflammatory reactions. The primary surgical purpose of cyanoacrylate was to close skin incisions.
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Albumin and Glutaraldehyde: These types of tissue adhesives have been used as adjunctive treatments for great vessel hemostasis. It has excellent strength and strong adhesion to tissue in 2 to 3 minutes. Mainly used in complex cardiac surgery to help seal the separated layers of the aortic wall.
Conclusion
A hemostat is a medical device or bandage used to stop bleeding from blood vessels in the body. It used for surgery and emergency hemostasis. The process of stopping blood flow from blood vessels is called hemostasis. Hemostasis is most often induced during surgery when blood flow must be stopped in the specific part of the body undergoing surgery. It is also done to stop bleeding from deep cuts and other injuries when the bleeding takes a long time to stop and a person's life is in danger.
