Medical devices used in modern medicine differ greatly in purpose, size, complexity of configuration, materials included in their composition, and methods of application. Among them are instruments made from heat-resistant metals, polymers, rubber, glass, those using fiber-optic technology, and others. Particularly diverse are medical devices for dentistry: surgical, therapeutic, endodontic, rotary instruments, molds, etc.

Disinfection solutions are prepared in enameled, metal, glass, or plastic containers with lids and labeling (name of the agent, manufacturing date, concentration, purpose). Instruments are fully immersed in the working disinfectant solution; detachable instruments are immersed disassembled, filling cavities and channels.

Instruments with locks and hinges should be disinfected in the open position.

Devices must be completely covered by the disinfectant solution. For this reason, the soaking bath should not be overloaded.

Instruments with cavities should have no air inside. Special attention must be given to instruments with narrow lumens (tubes and cannulas) and those with cavities that are difficult to clean, ensuring the solution fills them internally (without air bubbles), or syringes should be used for this purpose.

The next stage of processing reusable medical devices that require sterilization is pre-sterilization cleaning (PSC). According to industry standard 42-21-2-85, pre-sterilization cleaning can be performed by soaking and boiling, manually or mechanically. Boiling is conducted in a 1.5% solution of "Lotos," "Lotos-automat," "Astra," "Aina," "Marichka," "Progress"; in 2% baking soda solution for 15 minutes; hydrogen peroxide with detergents may also be used.

By their composition, contaminants are carbohydrates, fats, proteins, and lime deposits. To remove them from instruments, they must be converted into water-soluble compounds. This can be achieved by breaking down large molecules into simpler components that dissolve well in water, for example, using enzymes. Such agents are compatible with ultrasonic devices, since mechanized cleaning of medical instruments involves the use of such devices or washing machines.

Therefore, today a number of modern agents for PSC have been developed and proposed that include not only detergents but also enzymatic systems that ensure cleaning from protein, fat contaminants, and residues of medicinal products.

When choosing a disinfectant, recommendations of the medical device manufacturer, methodological guidelines, and instructions for use should be considered.

For example, chlorine-containing agents are recommended for corrosion-resistant devices. Alcohol-based aerosols (as well as wipes soaked with these solutions) can be used for disinfecting surfaces of anesthesiology equipment and dental handpieces. To save costs and reduce processing time, it is advisable to use innovative composite agents that, due to their components, allow combining disinfection and pre-sterilization cleaning in one step. Quaternary ammonium compounds, tertiary ammonium compounds (amine derivatives), guanidine derivatives have good detergent and cleaning properties, while aldehydes, on the contrary, fix organic contaminants. Therefore, when choosing an aldehyde-containing agent for combined PSC + disinfection processes, the possibility of fixation of organic contaminants on the surfaces of devices (especially on rough surfaces of lock parts and hard-to-clean places) must be taken into account. Additionally, some chemical compounds are incompatible with each other, such as aldehydes and amine derivatives. In aged, fixed organic contaminants, aldehyde residues may remain. For this reason, to avoid undesirable chemical reactions (manifesting as precipitation and dark spots on the surfaces of devices) when switching from an aldehyde-containing preparation to a disinfectant with amine derivatives, it is necessary to additionally perform thorough cleaning of the devices with an enzyme-containing agent.

After disinfection, instruments are rinsed with water until the disinfectant odor disappears. Tap water usually contains salts. The presence of chlorides and mineral substances, which cause water hardness, is especially undesirable. Upon evaporation, salts precipitate as deposits. Lime compounds in hard water cause deposits on instruments. High chloride content may cause pitting corrosion. It is necessary to remember that chlorides are always present in water but in varying concentrations. All this negatively affects and can lead to damage of the structural materials of medical devices during subsequent sterilization.

Therefore, an obligatory rule of PSC is rinsing devices with distilled water.

That is, pre-sterilization cleaning or disinfection + PSC ends with washing the skin device using swabs or wipes, rinsing with running water, rinsing with distilled water, and then drying the medical devices (the duration of the steps is indicated in regulations or methodological recommendations on the use of agents).

Usually, the working solution of the disinfectant is used once. The working solutions of some disinfectants are used not once, but during several days or a work shift if this is provided by the usage regulations. At the same time, quality control of the working solution is carried out visually by organoleptic signs (color change, appearance of flakes, sediment, turbidity). Obviously, this method of control may be subjective and cannot guarantee the proper content of active substance. It is different when a simple and quick method for controlling the quality of the working solution is developed and applied for the disinfectant, for example, test strips impregnated with a special substance, the color change of which indicates whether the working solution can continue to be used.

For medical devices subject to mandatory sterilization and that cannot be sterilized by high temperature or steam under pressure (autoclaving) due to the peculiarities of the materials used, chemical sterilization methods may be used. Agents with sporicidal properties are applied—aldehyde-containing, peroxide compounds—that do not damage medical devices. Before chemical sterilization, devices undergo all stages of processing. After the required exposure time, devices are washed only with sterile water. The stages of sterilization and preparation of devices for further use must be carried out in aseptic conditions.

When choosing a disinfectant for use in healthcare facilities, it is necessary to consider the working conditions of the personnel. If the rooms where working solutions of the disinfectant are prepared are not equipped with mechanical ventilation, and personnel do not use special respiratory protection, the choice of aldehyde-containing or other compounds requiring strict safety measures to preserve workers’ health may be considered unsuccessful (the rules for working with specific disinfectants are outlined in regulations or methodological guidelines for their use).

To determine the need of a healthcare facility for disinfectants for decontaminating medical devices, the following calculations can be used.

The consumption of disinfectants for decontaminating syringes, kits, sets for childbirth is determined according to norms. For other devices, it is based on actual consumption required for complete immersion in solution and filling of cavities.

The cost of 1 liter of working solution Ci is calculated by the formula:

Ci = (A × B) / 1000.0

where:

A — cost of 1 liter (or kg) of disinfectant concentrate in UAH;

B — amount in ml (or g) of the preparation needed to prepare 1 liter of working solution (provided in tables in methodological instructions);

1000.0 — 1000 ml.

Taken and adapted from the journal "Chief Medical Nurse."