Mechanical antisepsis: goals and methods
The main objective of mechanical antisepsis is to deprive microorganisms of a nutrient medium. To achieve this, devitalized tissues, fibrin deposits, and purulent exudate are physically removed from the wound defect. The elimination of non-viable structures has an indirect effect on the microflora, promoting rapid sterilization of the wound.
There are two main variants of surgical intervention:
- Primary surgical debridement (PSD). The goal of the manipulation is the complete excision of the bottom, walls, and edges of the wound strictly within healthy tissue limits. Along with the excised mass, hemorrhages, hematomas, foreign bodies, and the microflora residing within them are removed. A key success factor here is time: the earlier the operation is performed, the higher the chances of achieving absolute sterility.
- Secondary surgical debridement (SSD). Performed if the PSD was inadequate or performed too late, causing infection to actively proliferate in the tissues. SSD is also indicated for initially purulent processes (after opening a phlegmon or abscess). The cardinal difference from PSD is that the edges and walls are not excised here. The surgeon merely removes pus, fibrin, and necrosis mechanically (using a scalpel, scissors, vacuuming, or a directed fluid jet), opens blind pockets, and eliminates purulent streaks. Complete sterility cannot be achieved with SSD, but the microbial load drops sharply, giving the tissues a chance for normal healing.
Drainage: principle of action and gauze tampons
Drainage is necessary to allow wound discharge to freely flow out into the external environment—into the applied dressing or a special reservoir. There are several classical ways to organize such an outflow.
Gauze tampon A strip of gauze is always inserted loosely into the wound cavity. The drainage effect is based on the physical property of hygroscopicity: the fabric simply absorbs pus, blood, and exudate.
- Limitations: The tampon drains fluid effectively for no more than 8 hours. After becoming fully saturated, it transforms into a dense "plug" that disrupts the outflow of secretions.
- How to enhance the effect: To make the drainage work more actively, the gauze is moistened with a hypertonic solution (usually a 5–10% solution of NaCl). Due to the high osmotic pressure, fluid from the tissues begins to rush rapidly into the dressing.
Mikulicz-Radetzky tampon This is a special construction for prolonged drainage. A wide gauze napkin, with a strong thread sewn to its center, is placed on the walls and bottom of the wound. An improvised "sack" is formed, into which individual gauze tampons are packed tightly. As they become saturated, the inner tampons are removed and replaced with fresh ones, while the outer napkin-"sack" remains in place. When pus stops being secreted, the entire structure is removed by pulling on the central thread.
Tubular and irrigation drainage
Tubular drainage Such systems are made of polyvinyl chloride or rubber. They come in various diameters and are placed in wounds, joint cavities (in purulent arthritis), the pleural cavity (in empyema), or the abdominal cavity (in peritonitis). Through the tube, breakdown products and pus flow into a dressing or a vessel filled with antiseptic, which reduces bacterial contamination around the wound. Through such drains, chemical antiseptics, antibiotic solutions, and proteolytic enzymes can be introduced directly into the focus of inflammation.
Irrigation drainage This is a powerful method combining the principles of physical and chemical antisepsis. Two tubes are placed in the cavity: an antibacterial solution is continuously supplied through one, and outflow occurs through the other.
- Mechanism: Continuous flushing physically washes away blood, fibrin, and pus.
- Indications: Used for complex wounds, peritonitis, and purulent pleurisy.
- Flow enzymatic dialysis: If proteolytic enzymes are added to the flushing solution, it allows dead tissues and fibrin deposits to dissolve very rapidly, repeatedly accelerating wound cleansing.
Briefly: answers to topical questions
What physical methods and instruments are used by the surgeon to cleanse the wound during SSD?
To cleanse the wound during secondary surgical debridement (SSD), mechanical methods for removing necrotic tissues, pus, and fibrin are used. The surgeon uses the following instruments and physical methods:
- Scalpel — for mechanical excision of tissues.
- Scissors — for removing non-viable structures.
- Vacuuming — for aspiration of wound contents.
- Pressure jet irrigation — for effective washing out of pus and fibrin.
Also, during SSD, opening of purulent pockets and evacuation of streaks are mandatory.
What types of primary surgical debridement (PSD) are distinguished depending on the timing of execution?
Depending on the time elapsed since the injury, three main types of primary surgical debridement (PSD) are distinguished.
- Early PSD — performed within 24 hours after receiving the injury.
- Delayed PSD (primary-delayed) — performed in the period from 24 to 48 hours for the purpose of infection prevention and creating conditions for healing.
- Late PSD (primary-late) — carried out after 48 hours in case of late presentation of the patient.
What are the main types into which drainage is divided according to its mechanism of action?
According to the mechanism of action, drainage is divided into two main types: passive and active.
- Passive drainage — carried out due to the outflow of fluid into the external environment. Gauze tampons are used (working due to hygroscopicity), as well as special devices, such as the Bülau underwater valve or the Bobrov jar.
- Active drainage (aspiration) — involves the forced removal of contents by creating controlled negative pressure using electrical suction devices.
Additionally, irrigation drainage is distinguished, combining a constant supply of an antibacterial solution and outflow.
PSD — Perimeter of healthy tissues (excise edges). SSD — Clear out pus (do not touch edges, only remove necrosis and secretions).
Class and exam questions
Why does a gauze tampon stop working after 8 hours?
During this time, it becomes completely saturated with wound discharge, loses its hygroscopicity, and turns into a dense plug that blocks the outflow of exudate.
Why is a gauze tampon moistened with a 5–10% sodium chloride solution?
This is a hypertonic solution that creates high osmotic pressure in the wound. Due to this, fluid is more actively drawn from the inflamed tissues into the dressing.
What is the main difference between PSD and SSD?
During PSD, the edges, walls, and bottom of the wound are excised within healthy tissue limits. During SSD, excision of the edges is not performed; the physician merely removes necrotic masses, fibrin, and pus.
What else to study on this topic
- Technique and stages of primary surgical debridement (PSD)
- Application of proteolytic enzymes in purulent surgery
- Features of wound vacuuming during secondary surgical debridement
- Properties and types of solutions for irrigation drainage
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Other topics in the section "CHAPTER 2. ASEPSIS AND ANTISEPSIS"
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