Requirements for chemical antiseptics
For safe and effective use in surgical practice, agents must meet several strict criteria.
First, this is high efficacy: they must exert a powerful bactericidal or bacteriostatic effect on infectious agents. Second, safety during local application is mandatory — the solution must not cause systemic toxicity, allergies, or irritation of healthy tissues. The third important factor is stability. The agent must not be volatile in air, and its properties must not decrease in the presence of biological fluids, such as exudate, blood, or pus. Finally, the production of the agent must be economical.
Chemical antiseptics often outperform classical antibiotics precisely in purulent surgery. Antibiotics can lose their potency due to low penetration into inflamed tissues, and can also be inactivated by an acidic environment, inflammatory mediators, and necrotic masses. Antiseptics are much more resistant to these factors.
Methods of application in surgery
Chemical agents can be used both for direct action within the focus of infection and for systemic effects on the body.
Local application:
- Bandage application: using solutions, ointments, or powders for the treatment of wounds and burns (e.g., moistening tampons or washing).
- Introduction into closed cavities: the method combines physical and chemical antisepsis. The solution is introduced into the cavity (e.g., in pleurisy or peritonitis) followed by aspiration through drains (through-and-through drainage, peritoneal dialysis).
- Abdominal cavity sanitization: special agents safe for the systemic bloodstream are used (sodium hypochlorite, furazidine, hydroxymethylquinoxalinedioxide).
General application:
- Oral administration: tablet forms are used to prepare the gastrointestinal tract for surgery (suppression of local flora) and for systemic effect after absorption into the blood.
- Intravenous administration: certain drugs (furazidine, sodium hypochlorite) are injected directly into the vascular bed to combat severe infection.
Main groups of drugs
A multitude of compound classes are used in medical practice, the choice of which depends on the purpose of treatment.
- Iodine preparations: Classical 5% or 10% alcohol solution is used for treating abrasions and the surgical field. Complex agents are also used — a combination with potassium iodide (diluted with water 1:4.5) and povidone-iodine (0.1–1%), which is excellent for hand washing.
- Alcohols and aldehydes: Ethanol (Spiritus aethylicus) in 70% and 96% concentrations is used for suture material, hands, and optics. Formalin (Formalinum, 0.5–5% solution) is excellent for sterilizing drains and catheters.
- Quaternary ammonium compounds: Degmicid (Degmicidum, working solution 1:30) and benzalkonium chloride (1% and 10%). The latter is used for instruments, adding sodium carbonate for corrosion protection.
- Nitrofuran derivatives: Active against pyogenic cocci. Nitrofural (Nitrofuralum) is used as an aqueous solution of 1:5000 for washing fistulas.
- Chlorhexidine bigluconate (Chlorhexidini bigluconas): A 0.5% water-alcohol solution is prepared from the initial 20% solution (1:40 dilution in 70% ethanol). The surgical field is treated with it twice at a 2-minute interval.
Agents for disinfection and pre-sterilization cleaning
Combined agents with powerful detergent and antimicrobial properties are used to prepare equipment, furniture, and premises.
- «Alaminol»: contains surfactants, glyoxal, and alkyldimethylbenzylammonium chloride. Destroys bacteria (including the tuberculosis pathogen), viruses, and fungi. Metal instruments are immersed in a 5% solution for 60 minutes.
- «Lizafin-special»: possesses a similar broad spectrum. Endoscopes are soaked in a 1% solution for 60 minutes, and at a 2% concentration, the exposure time is reduced to 15 minutes.
- «Kemi-side»: aqueous solutions (0.5–2%) are used for twice-daily wiping of surfaces and plumbing fixtures.
- Perвомур (C-4 preparation): a mixture of performic acid and hydrogen peroxide. Used primarily for preoperative scrubbing of the surgeon's hands.
Before final sterilization, the quality of cleaning is mandatory checked using tests for residual blood (benzidine or amidopyrine test).
Briefly: answers to topical questions
What are the main classes of chemical antiseptics distinguished by their chemical structure?
Based on chemical structure, the following main classes of chemical antiseptics are distinguished:
- Halogens — iodine and chlorine preparations.
- Oxidizing agents — act through the release of oxygen.
- Acids and alkalis — acetic, boric, salicylic acids, ammonia.
- Alcohols — ethyl alcohol.
- Aldehydes — formaldehyde, hexamethylenetetramine.
- Detergents (surfactants) — decamethoxine, chlorhexidine, ethonium.
- Synthetic derivatives — derivatives of 8-hydroxyquinoline, 4-quinolone, quinoxaline, nitrofuran, phenol.
- Dyes — brilliant green, methylene blue, ethacridine lactate.
- Heavy metal compounds — salts of mercury, silver, zinc, copper.
Which drugs belong to the group of oxidizing agents and in which surgical pathologies are they used?
The group of oxidizing agents includes hydrogen peroxide, urea peroxide, and potassium permanganate. In surgical practice, they are used for the following pathologies:
- Hydrogen peroxide solution (Solutio Hydrogeniiperoxydi diluta) — used for the primary treatment of contaminated and purulent wounds, washing fistulas, empyemas, and abscesses, as well as for stopping capillary bleeding from superficial wounds.
- Urea peroxide (Hydroperitum) — used for washing wounds.
- Potassium permanganate (Kaliipermanganas) — used for treating purulent wounds, burns, and washing cavities.
What is the mechanism of the antimicrobial action of alcohols and aldehydes on microbial cells?
In the presented sources, the mechanism of the antimicrobial action of alcohols and aldehydes as separate groups is not described. It is indicated that organic solvents, including alcohol, disrupt hydrophobic interactions and can cause protein denaturation. The mechanism of action of aldehydes is not provided in the sources.
Class and exam questions
Why do antiseptics work better than antibiotics in the presence of pus?
Unlike many antibiotics, chemical antiseptics retain their stability and activity upon contact with tissue breakdown products, exudate, and the acidic pH characteristic of a purulent focus.
How to properly dilute chlorhexidine for surgical site preparation?
Factory-made 20% chlorhexidine bigluconate solution is taken and diluted with 70% ethyl alcohol in a 1:40 ratio. The result is a working 0.5% water-alcohol solution.
Why is sodium added when sterilizing instruments with benzalkonium chloride?
To prevent rusting (corrosion) of metal instruments, sodium carbonate is mandatorily added to the working benzalkonium chloride solution at the rate of 2 grams per 1 liter of solution.
What is the characteristic feature of furazidin usage compared to nitrofural?
Both drugs belong to nitrofuran derivatives, however, furazidine (0.1% solution) can be used not only locally, but also administered intravenously (up to 300 ml) for a systemic effect.
What else to study on this topic
- Mechanisms of reduced antibiotic efficacy in the inflammatory focus
- Performing benzidine and amidopyrine tests for occult blood
- Methods of through-and-through drainage and peritoneal dialysis
- Rules for the preparation and use of the Perвомур (C-4) preparation
- Interaction of chemical antiseptics with physical wound treatment methods
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