The proper processing of instruments used in healthcare settings or at home is an important safety measure against the transmission of infectious agents. A medical instrument is any tool used in patient care that contacts the body, ranging from simple scissors to complex reusable devices. Failing to correctly clean and disinfect these items allows microorganisms to persist on surfaces, potentially causing severe infections when the instrument is used again. Understanding the differences between cleaning, disinfection, and sterilization is the first step toward ensuring these tools are safe for their intended purpose.
Understanding the Required Cleanliness Level
The necessary level of processing depends entirely on the instrument’s intended use and where it contacts the body. Instruments that only touch intact skin, such as a stethoscope or blood pressure cuff, require the least rigorous treatment: simple cleaning and low-level disinfection. Items contacting mucous membranes or non-intact skin, like a nasal speculum, require a more thorough process. Tools that penetrate the skin or contact sterile body tissues, such as surgical instruments, demand the highest level of microbial elimination.
This hierarchy involves three distinct stages. Cleaning is the foundational first step, involving the physical removal of all visible soil, debris, and foreign material using water and specialized detergents. This step drastically reduces the number of microorganisms present. Disinfection follows cleaning and targets most pathogenic microorganisms, including many viruses and bacteria, but does not destroy all bacterial spores. Sterilization represents the complete destruction of all forms of microbial life, including highly resistant bacterial spores. An instrument must be sterile if it is used to penetrate the skin.
The Essential Manual Cleaning Steps
Immediate processing of instruments after use is recommended because dried biological material is much harder to remove. The initial step is to rinse the instrument under cool running water to remove gross soil immediately. Cool water is intentional, as hot water can cause proteins in blood and other fluids to coagulate and bind firmly to the surface, making subsequent cleaning difficult.
After the initial rinse, the instrument should be immersed in a specialized enzymatic or neutral pH detergent solution. These solutions break down organic materials without corroding the metal. Instruments should be fully submerged for 5 to 10 minutes to allow the detergent to penetrate hinges and crevices. During this manual cleaning process, wear personal protective equipment, including utility gloves and eye protection, due to contaminated materials and potential sharp objects.
Manual scrubbing must be thorough, using soft-bristled brushes to ensure all surfaces are reached. Pay particular attention to difficult-to-reach areas like hinges, serrations, and lumens, which may require a pipe cleaner or vigorous flushing. After scrubbing, the instrument must be rinsed completely in purified or distilled water to eliminate all detergent residue. Residual cleaning agents can cause staining, spotting, or damage to the instrument over time.
Accessible Disinfection Methods for Home Use
Once an instrument is clean, it is ready for disinfection using readily available methods. Boiling is a common method that achieves disinfection by exposing the clean instrument to moist heat. The instrument must be fully submerged in water and boiled for at least 20 minutes, starting only once the water reaches a rolling boil. Boiling is effective against many organisms but is a form of disinfection, not sterilization.
Chemical soaks provide another accessible disinfection pathway, using common household agents like isopropyl alcohol or household bleach. Isopropyl alcohol should be used at a concentration of 70%, as higher concentrations evaporate too quickly, reducing the necessary contact time. The clean instrument must be fully immersed for the duration specified by the product label, typically at least one minute, ensuring the surface remains wet throughout.
Household bleach, which contains sodium hypochlorite, is a broad-spectrum disinfectant but must be used with caution, particularly on metal instruments, as it is corrosive. For general disinfection, a solution of approximately 1:10 dilution of standard household bleach (5-6% concentration) with water is recommended. The diluted solution should be prepared fresh daily, as the active ingredient degrades quickly. Instruments should be exposed to the bleach solution for the required contact time, usually one minute, and then thoroughly rinsed with water to prevent corrosion. Never mix bleach with other chemicals, such as ammonia-based cleaners, because this can produce toxic gases.
Post-Cleaning Handling and Storage
After an instrument has been cleaned and disinfected, it must be dried completely before storage. Residual moisture creates an environment where microorganisms can rapidly re-grow and promotes corrosion on metal surfaces. Instruments should be dried using a lint-free cloth or allowed to air dry completely.
Once dry, each instrument must be visually inspected under adequate lighting. Confirm that no debris remains and check for signs of damage, such as pitting, cracks, or rust. If soil is still visible or if the instrument appears damaged, it must be re-cleaned or disposed of immediately. Hinged instruments may benefit from a manufacturer-approved lubricant to maintain smooth operation.
The final step is to store the instruments in a manner that preserves their cleanliness until the next use. Storage must be in a clean, dry, and dust-free environment, ideally within a closed drawer, cupboard, or sealable container. Instruments should be kept away from sources of moisture, such as sinks, which can compromise the clean state. If a disinfected instrument is stored for a long period or its packaging is damaged, it should be fully re-processed before its next use.