Physical and chemical methods of hemostasis

Physical methods of hemostasis

Physical methods are based on utilizing the thermal factor. Depending on the temperature applied, different physiological effects are achieved. Heat exposure leads to denaturation and coagulation of tissue proteins, which physically plugs the vessel. Conversely, local application of cold causes pronounced vasospasm, reducing the volume of blood loss.

Simple examples of thermal exposure from clinical practice:

• Diffuse bleeding from bone: gauze pads soaked liberally in a hot isotonic sodium chloride (NaCl) solution are applied to the wound surface.
• Subcutaneous hematomas: an ice pack is applied locally to prevent the worsening of edema and hemorrhage.
• Gastric bleeding: the patient is given small pieces of ice to swallow.

More complex hardware techniques include diathermocoagulation, laser radiation, and cryosurgery.

Hardware-based thermal methods

Diathermocoagulation This is the basic and most common thermal technique in the operating room. The method works by locally passing high-frequency alternating current.

• Indications: arresting bleeding from vessels of the subcutaneous adipose tissue, muscle mass, and small cerebral vessels.
• Main condition for success: the operative field (wound) must be completely dry before applying the coagulator.
• Safety: carbonization of the coagulated tissues must be strictly avoided, as the resulting fragile eschar is easily rejected, provoking dangerous secondary hemorrhage.

Laser coagulation This approach utilizes radiation focused into a dense beam. The laser provides extremely precise impact.

• Indications: bleeding gastric ulcers, interventions in patients with coagulation disorders (e.g., hemophilia), as well as extensive oncological surgeries.

Cryosurgery and local freezing The method consists of targeted surgical exposure to cold. Local freezing (cryonecrosis) is actively used for tumor destruction, allowing targeted destruction of pathological foci with minimal trauma to surrounding healthy cells.

• Indications: surgeries on highly vascularized organs (brain tissue, liver and kidney parenchyma).

Chemical and biological agents

This group of hemostatic agents is conventionally classified by their route of administration (delivery mechanism to the bleeding source). There are two main categories: resorbptive (systemic) and topical agents.

Resorbptive agents Such substances are introduced into the body, absorbed into the systemic circulation, and exert a general effect on the hemostatic system. Their main sphere of application is massive internal bleeding when direct access to the damaged vessel is difficult or impossible.

Topical agents and biomaterials Topical agents work only upon direct physical contact with the traumatized bleeding surface. They are extremely in demand in surgery for parenchymatous bleeding (e.g., in deep ruptures or incisions of the liver).

For local tamponade, both the patient's own tissues and special preparations are used:

1. Patient's autologous tissues: fragments of muscle tissue or an omental flap (used both as a free graft and a pedicle flap).
2. Specialized biological products: fibrin film, biological antiseptic tampon, as well as hemostatic sponges (collagen or gelatin).

These materials are indicated for capillary and parenchymatous hemorrhages from muscle tissue, bones, parenchymatous organs, as well as for complex tamponade of dural venous sinuses.

Use of thrombin and combined approaches

A special place among biological preparations is held by thrombin, an enzymatic preparation derived from donor blood plasma.

The mechanism of its action consists in the direct stimulation of the conversion of soluble fibrinogen into insoluble fibrin threads.

• Application technique: dry powder is dissolved in isotonic NaCl solution, then sterile gauze pads or a hemostatic sponge are thoroughly soaked with this solution, after which it is applied directly to the wound surface.
• Indications: effective for capillary and parenchymatous bleeding.
• Important contraindication: thrombin is strictly prohibited for use in bleeding from large vessels. Entry of the drug into the systemic main bloodstream can provoke extensive thrombosis, leading to a fatal outcome.

Combined methods To achieve maximum reliability, surgeons often combine several different methods. For example, a classical vascular suture can be supplemented by wrapping with muscle tissue externally or applying medical glue. In surgeries on parenchymatous organs, the placement of hemostatic sutures is often combined with suturing biological tampons, which minimizes the risk of suture cut-through and enhances local hemostasis.

Briefly: answers to topical questions

What else to study on this topic

• Detailed mechanisms of electrosurgical tissue impact
• Types of hemostatic sponges and their biodegradation
• Vascular suture technique
• Features of hemostasis in neurosurgery (dural venous sinuses)
• Application of laser in the treatment of bleeding ulcers

Other topics in "CHAPTER 5. BLEEDING"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.