The process of sterilizing instruments in an autoclave uses pressurized steam to eliminate all microbial life. This process is entirely dependent upon the quality of the cleaning that precedes it. Cleaning is not sterilization itself, but rather the preparation that makes true sterilization possible. The purpose of this initial step is the physical removal of debris, including organic matter known as bioburden, along with any inorganic soil or residues. Steam cannot effectively penetrate dried contaminants, meaning that any microorganism shielded by this soil will survive the autoclave cycle. Therefore, thorough cleaning is the foundation for achieving a sterile instrument.
Immediate Handling and Transport
The moment an instrument is used, a race begins to prevent organic soil from drying and adhering to the surfaces. This immediate point-of-use care is a simple defense against difficult-to-remove, hardened bioburden. Instruments should be wiped down with a sponge or cloth moistened with water to remove gross debris while still in the procedure area.
If a delay is expected before the full cleaning process can begin, the instruments must be kept moist. This is often accomplished by using a specialized enzymatic spray, gel, or foam designed to prevent the drying of proteinaceous material. This practice is preferred over soaking in plain water, and instruments should never be soaked in saline, as the sodium chloride can accelerate corrosion and pitting on stainless steel surfaces.
Hinged instruments must be opened and fully extended during this initial handling phase to expose their box locks and serrations to the moistening agent. Instruments must then be safely transported to the central processing area in a contained, sealed tray or bin. This contained transport minimizes the risk of spills, aerosolizing contaminants, and accidental sharps injuries to personnel.
Detailed Cleaning Procedures
Intensive cleaning involves either manual scrubbing or automated processes, both designed to mechanically remove all residual soil. For manual cleaning, technicians must use soft-bristled nylon or plastic brushes, as metal brushes can scratch the instrument’s protective surface. All surfaces, especially complex areas like hinges, box locks, and teeth, must be scrubbed while keeping the instrument submerged to prevent the creation of contaminated aerosols.
Instruments with multiple parts must be fully disassembled before cleaning to ensure that every surface is accessible to the detergent and brush. Cannulated instruments, which have hollow channels or lumens, require specific attention, as soil can easily become impacted inside. The lumens must be force-flushed using a water pistol or syringe, followed by brushing the internal channel with a brush sized appropriately to create friction against the inner walls.
Automated cleaning methods utilize specialized equipment to enhance efficiency and consistency. Ultrasonic cleaners work by generating high-frequency sound waves, which create millions of microscopic bubbles in the cleaning solution. This phenomenon, known as cavitation, causes the bubbles to rapidly implode, generating tiny vacuum forces that dislodge soil from fine crevices and hard-to-reach areas.
Instrument washer-disinfectors operate similarly to dishwashers, combining high-pressure water jets with specialized detergents and high-temperature thermal disinfection cycles. For cannulated instruments, these machines often feature specific ports that connect directly to the lumens, forcing the cleaning solution through the channels. Automated cleaning requires instruments to be pre-cleaned to remove gross soil, as the heat from the washer can otherwise “bake” residual organic matter onto the surface.
Essential Safety and Chemical Considerations
All personnel involved in instrument cleaning must wear appropriate Personal Protective Equipment (PPE) to protect against exposure to blood-borne pathogens and chemical agents. This gear typically includes heavy-duty, puncture-resistant utility gloves, fluid-resistant gowns, and face shields or protective eyewear. Following these protocols is necessary because the cleaning process involves handling contaminated items that can create splashes and aerosols.
The choice of cleaning agent must be a neutral pH detergent, ideally one that is enzymatic. Enzymatic detergents contain enzymes like proteases, lipases, and amylases that chemically break down proteins, fats, and starches, effectively loosening the bioburden. Non-enzymatic, neutral pH detergents are also suitable, but they rely more heavily on mechanical action.
It is prohibited to use household cleaners like laundry detergent, dish soap, or bleach. These products often have high or low pH levels, which can be corrosive to the stainless steel, causing pitting, discoloration, or a breakdown of the protective surface layer. Abrasive materials, such as steel wool, wire brushes, or scouring pads, must also be avoided, as they create microscopic scratches that harbor microorganisms and initiate rust.
The quality of the water used for mixing detergents and rinsing is also important for preventing instrument damage. Using filtered, demineralized, or distilled water is recommended for the final rinse, as tap water contains minerals that can leave deposits on the instrument surface. These mineral deposits can interfere with the sterilization process and lead to staining or corrosion.
Final Preparation for Sterilization
After the intensive cleaning step, instruments must be thoroughly rinsed to remove all traces of residual detergent and enzymatic solution. Residual cleaning agents can impede steam penetration and lead to toxic residues or instrument damage. A final rinse with purified water, followed by a flush of all lumens, ensures that no chemicals remain in the channels or on the surfaces.
A visual inspection of every instrument must follow the rinse cycle. Technicians check for any remaining soil, focusing on the hinges, crevices, and box locks where debris often hides. The instruments are also inspected for signs of damage, such as rust, pitting, cracks, or dull edges, and all movable parts are checked for proper functionality.
Complete drying is required before sterilization, as lingering moisture can cause corrosion and interfere with the steam sterilization process. Instruments can be dried using specialized drying cabinets, forced air, or a lint-free towel. Once fully dry, hinged or moving instruments can be treated with an approved, water-soluble lubricant, which prevents friction and preserves function during the autoclave cycle.