Pre-sterilization cleaning and preparation

Difference between sterilization and disinfection

Medical instruments require rigorous processing to prevent contact and implantable wound infections. It is important to distinguish between two key terms. Disinfection aims exclusively at destroying pathogenic microbial flora. Sterilization (from the Latin sterilis — barren) implies the total elimination of all microorganisms whatsoever from objects, materials, and solutions, including their resistant spore forms. For sterilization to be successful, the material requires high-quality pre-sterilization cleaning (the first preparation stage).

Basic processing algorithm for uninfected instruments

Medical staff always perform pre-sterilization cleaning wearing rubber gloves. If instruments are contaminated with blood, they must under no circumstances be left to dry out.

The standard cycle includes the following steps:

1. Rinsing under running water for 5 minutes using brushes in a separate sink.
2. Soaking in a special detergent solution heated to 50°C for 15–20 minutes (syringes must be disassembled).
3. Thorough washing in the same solution using brushes, paying special attention to box locks, serrations, and teeth.
4. Rinsing with warm running water (5 minutes).
5. Rinsing in distilled water (1 minute).
6. Drying in a hot-air sterilizer at 85°C until moisture is completely removed.

After this, the instruments are fully ready for packaging and subsequent sterilization.

Cleaning features for specific contaminants

The algorithm changes significantly if the instruments are contaminated with pus, intestinal contents, or traces of an anaerobic infection.

• Pus and intestinal contents: Before standard cleaning, instruments are soaked for 30 minutes in an enamel container with a 0.1% diocide solution, washed with brushes directly in it, rinsed with running water, and only then transferred to the standard processing scheme.
• Anaerobic infection: This is the strictest regimen. The devices are soaked for 1 hour in an aggressive mixture (6% hydrogen peroxide and 0.5% detergent), brushed, and then boiled for 90 minutes. Only after this are they prepared as uninfected. Such instruments are sterilized fractionally: exactly 24 hours are allowed to elapse between processing and autoclaving to give potential spores time to germinate.

Specifics of preparing reusable devices

Some items require an individualized approach during cleaning:

• Needles (injection, puncture): After lumen flushing and mechanical cleaning with a stylet, the needle is boiled twice. First for 30 minutes in a 2% sodium bicarbonate solution, and 8–12 hours later for 40 minutes in distilled water. The lumen must be purged with ether or alcohol for drying.
• Rubber gloves: When contaminated with blood, they are washed with running water right on the hands, dried, soaked in a 0.5% ammonia solution for 30 minutes, rinsed, and hung up to dry. Gloves soiled with pus must be destroyed. In case of extreme necessity, they are soaked in a disinfectant for an hour, but thereafter used exclusively in the purulent dressing room.
• Transfusion sets: Reused only out of necessity. They are completely disassembled, the rubber tubing is kneaded under water, soaked for 2 hours at 60°C, and then boiled twice in distilled water (30 and 20 minutes, respectively).

Quality control and preparation for packaging

The benzidine test helps evaluate cleaning quality and the completeness of blood removal. Three drops each of a 1% benzidine solution and hydrogen peroxide are applied to the instrument. The appearance of a blue-green color indicates hidden traces of blood, and the cleaning must be repeated.

At the second stage, cleaned instruments are packaged for sterilization. In dry-heat sterilizers, devices are placed in metal boxes vertically and strictly in a single layer. For autoclaving, sterilization boxes (drum containers), cloth bags, or special thick paper bags in two layers are used.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Specifics of packing dressings and linen into sterilization boxes (drum containers).
• Rules for chemical disinfection and sterilization of anesthesia and respiratory equipment.
• Fractional sterilization technique for effective control of spore-forming microflora.
• Specifics of preparing and sterilizing specialized surgical kits (cardiovascular, bone).

Other topics in the section "CHAPTER 2. ASEPSIS AND ANTISEPSIS"

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