What are hemostatic agents?
Hemostatic agents are substances or materials used to expedite blood clotting and stop bleeding, particularly when conventional methods like direct pressure or suturing are ineffective or impractical. These agents are critical in surgical settings to manage oozing from large surfaces and in emergency trauma care for life-threatening hemorrhage. They can be applied topically to a wound or, in some cases, administered systemically.
The Most Commonly Used Hemostatic Agents by Application
The specific hemostatic agent most frequently used varies by the medical setting and the type of bleeding that needs to be controlled.
In the Operating Room
In surgery, where bleeding is often diffuse or from large surface areas, absorbable agents are particularly common.
- Absorbable Gelatin Sponge (e.g., Gelfoam, Surgifoam): Derived from purified animal skin gelatin, these porous, pliable sponges absorb many times their weight in blood, providing a matrix and physical barrier for clot formation. They are often saturated with topical thrombin to enhance the clotting effect and are absorbed by the body in 4 to 6 weeks.
- Oxidized Regenerated Cellulose (ORC) (e.g., Surgicel): This knitted, sterile fabric is derived from plants and is highly effective for controlling diffuse bleeding. When it contacts blood, it swells into a gelatinous mass that aids clotting and also has antibacterial properties due to its low pH. Excess material should be removed after hemostasis to prevent inflammation or delayed healing.
In Emergency and Trauma Care
In prehospital or combat situations, the focus is on rapid, reliable control of severe external hemorrhage, for which specialized dressings are most common.
- Kaolin-Impregnated Gauze (e.g., Combat Gauze): Kaolin is a mineral that, when impregnated into gauze, directly activates the intrinsic clotting pathway, significantly accelerating clot formation. Combat Gauze is the hemostatic agent of choice for the U.S. military and many other forces due to its efficacy in managing compressible bleeding.
- Chitosan-Based Dressings (e.g., Celox, HemCon): Chitosan is a natural, mucoadhesive polysaccharide derived from shellfish. Its mechanism works independently of the body's normal clotting cascade, as the positively charged chitosan molecules bind strongly to negatively charged red blood cells, forming a gel-like clot. This makes it effective even in coagulopathic patients.
Comparison of Common Hemostatic Agents
| Agent | Mechanism | Common Application | Pros | Cons |
|---|---|---|---|---|
| Absorbable Gelatin Sponge (Gelfoam) | Provides a physical matrix, absorbs blood, can be used with thrombin. | Surgical procedures, especially internal bleeding. | Biodegradable, can be left in place, versatile with added thrombin. | Potential for swelling, foreign body reaction, may potentiate bacterial growth. |
| Oxidized Regenerated Cellulose (Surgicel) | Creates a gelatinous matrix, lowers pH, antibacterial properties. | Surgical use for diffuse bleeding; preferred in contaminated areas. | Biodegradable, antibacterial effect, provides a scaffold for clotting. | Low pH can cause inflammation, inactivates thrombin, potentially delays healing. |
| Kaolin-Impregnated Gauze (Combat Gauze) | Activates the intrinsic clotting cascade (Factor XII). | Military and prehospital trauma for severe external bleeding. | Proven efficacy in combat, easy to pack into deep wounds. | Requires manual pressure, less effective for some noncompressible bleeding. |
| Chitosan-Based Dressings (Celox) | Works independently of the clotting cascade by binding to red blood cells. | Field trauma, effective on coagulopathic patients. | Works quickly regardless of coagulation status, biodegradable. | Potential for shellfish allergy in sensitive patients, granular form can be messy. |
| Fibrin Sealants (Tisseel) | Mimics the final stage of the clotting cascade using concentrated fibrinogen and thrombin. | Specialty surgeries (vascular, neurosurgery) for rapid hemostasis. | Very rapid and effective, forms a strong clot. | Expensive, requires complex preparation, risk of viral transmission (for human-derived products). |
How These Agents Work
The mechanisms of action for hemostatic agents vary widely:
- Passive Agents: These act as a physical scaffold, such as absorbable gelatin sponges and oxidized cellulose. They absorb blood, concentrating platelets and clotting factors, and swell to create a physical barrier.
- Biologically Active Agents: These directly participate in the coagulation cascade. Topical thrombin, for instance, converts fibrinogen to fibrin at the bleeding site, while fibrin sealants provide a concentrated supply of procoagulant factors to form a rapid, stable clot.
- Mineral-Based Agents: These agents, like kaolin and zeolite, accelerate the intrinsic clotting pathway, speeding up the body's natural coagulation process.
- Mucoadhesive Agents: Chitosan-based agents rely on an electrostatic attraction to red blood cells, creating a physical seal independent of the coagulation cascade.
Conclusion
The question of what is the most commonly used hemostatic agent? has no single answer, as the preferred agent is highly dependent on the medical context and type of hemorrhage. In the controlled environment of a surgical theater, time-tested and absorbable options like gelatin sponges and oxidized cellulose are widely utilized due to their efficacy and biocompatibility. Conversely, in critical prehospital or military trauma scenarios, kaolin- or chitosan-impregnated dressings are the standard for managing severe external bleeding, offering rapid clotting independent of the patient's coagulation status. The development of new hemostats continues, but understanding the mechanisms and appropriate application of these existing agents is key for effective hemorrhage control across different clinical situations. For further reading, an overview of agents used for emergency hemostasis is available via PubMed Central.
