Best practices for the disinfection and cleaning of medical equipment

One of the most effective methods of preventing the spread of viruses, including SARS-CoV-2, consists of applying good hygiene and surface decontamination practices. Cleaning is a preliminary, mandatory, and permanent step in every activity or procedure for removing dirt (organic and inorganic matter) from various surfaces.

Cleaning: is carried out through mechanical or manual operations using physical and/or chemical agents and is mandatory in healthcare facilities so that medical activity can be carried out under optimal safety conditions.

Disinfection: represents the procedure for destroying the majority of pathogenic or non-pathogenic microorganisms on surfaces using physical and/or chemical agents, such as disinfectant products. It is essential that cleaning is always performed first, followed by disinfection or sterilization.

CLEANING

Cleaning can be done manually or by using mechanical cleaning machines (for example, an ultrasonic washer-disinfector, a standard washer, or a washer-sterilizer) after gross dirt has been removed. Automatic machines can have increased productivity because the cleaning process is more efficient, thereby also reducing staff exposure to blood and body fluids. Manual cleaning may be necessary for delicate or more complex items. It is important to consult the cleaning instructions of the equipment/device manufacturer in question, including specifications for the type of detergent to be used, water temperature, and cleaning methods. In the case of manual cleaning, when handling multiple pieces of equipment/devices simultaneously, it is recommended to use a hand disinfectant solution or to wash your hands before touching the already cleaned equipment/devices again (to ensure they are not contaminated with pathogenic microorganisms picked up from equipment that has not yet been cleaned but was touched previously).

Procedures included in the cleaning process:

1. Physical removal of residual organic materials

• Completely submerge immersible items during the cleaning process to minimize the aerosolization of microorganisms.
• Minimize aerosol production when cleaning non-immersible equipment/devices.
• Remove gross dirt using tools such as brushes and cloths.

2. Manual cleaning

• Clean equipment/devices that have lumens with a special brush according to the manufacturer's instructions, then rinse manually or mechanically with a detergent-based solution.
• Check equipment/devices with lumens for obstructions and leaks.
• Manually clean very dirty equipment/devices before mechanical cleaning.
• Soak the equipment/device in a hospital-approved instrument soaking solution.
• Do not use saline solution as a soaking solution, as it damages some medical equipment/devices.
• Ensure that detergents (including enzymatic cleaning agents) are suitable for the equipment/device being cleaned (the products used must be approved by the equipment/device manufacturer).
• Avoid prolonged soaking (e.g., leaving in liquid overnight) of equipment/devices.

3. Mechanical cleaning

• Ensure that the equipment/device to be cleaned is compatible with mechanical cleaning and the chemical solutions being used.
• Ultrasonic washers: are especially recommended for any semi-critical or critical medical equipment/device that has mobile connections, cracks, lumens, or other hard-to-clean areas.
• Washer-disinfectors: are recommended for medical equipment/devices that can withstand mechanical cleaning, thereby also reducing the potential risk to staff.

DISINFECTION

Disinfection is the procedure of inactivating disease-causing microorganisms. The disinfection of medical equipment/devices falls into two main categories: low-level disinfection and high-level disinfection.

1. Low-level disinfection

Low-level disinfection eliminates vegetative ("live") bacteria, some viruses, some fungi, but does not destroy resistant microorganisms such as Mycobacterium tuberculosis or bacterial spores. This method is used for non-critical medical equipment/devices and some environmental surfaces. Low-level disinfectants include 3% hydrogen peroxide, 0.5% accelerated hydrogen peroxide formula, some quaternary ammonium compounds, phenolic solutions, and diluted sodium hypochlorite (e.g., bleach). Disinfection is performed after the equipment/device is thoroughly cleaned, rinsed, and excess water is removed. A surface disinfectant or instrument disinfectant can be used, applied by wiping, immersion, spraying, or nebulization (cold fog).

2. High-level disinfection

Eliminates vegetative bacteria, enveloped viruses, fungi, non-enveloped viruses, as well as Mycobacterium tuberculosis (the bacterium that causes tuberculosis). This method of disinfection is used for semi-critical medical equipment/devices. High-level disinfectants include 2% glutaraldehyde, 6% hydrogen peroxide, 0.2% peracetic acid, 2-7% accelerated hydrogen peroxide formulations, and 0.55% ortho-phthalaldehyde. Pasteurization also achieves high-level disinfection. Disinfection is performed after the equipment/device is thoroughly cleaned, rinsed, and excess rinse water is removed.

Contaminated surfaces can predispose to illness. It is important to avoid contamination situations within the medical unit by disinfecting the instruments used. This can be done with Sporycide – a high-level disinfectant concentrate for instruments but also for work surfaces. It efficiently cleans and disinfects surfaces and the micro-aero-flora in private spaces and public health areas, having a certified biocidal action and a rapid effect (5 minutes).

In the category of high-level instrument disinfectants is also Sterisol, which is a product intended for long-term use for cleaning instruments and the ambient environment in rooms. It can be used for disinfecting equipment, containers, and utensils. This disinfectant has the following characteristics: it has a certified biocidal action, does not contain aldehydes, phenols, or alcohol, quickly dissolves protein residues, and is suitable for any type of material.

Disinfection methods for semi-critical medical equipment/devices

1. Liquid chemical disinfection

Achieves the destruction of all microorganisms and a large number of bacterial spores. The contact time required for the chemical substance with the treated substrate is several hours. It is important to follow the manufacturer's recommendations regarding contact time and conditions of use. Chemical substances that achieve chemical disinfection/sterilization are: Glutaraldehyde (2%), stabilized Hydrogen peroxide (6%), Peracetic acid (various concentrations).

For liquid chemical disinfection, it is important to consider the following:

• each device must be thoroughly rinsed after disinfection, according to the chemical product manufacturer's instructions
• the quality of the rinse water (i.e., sterile, filtered, or tap water) – this will depend on the intended purpose of the device's use
• non-critical devices can be dried by air drying or other methods

2. Pasteurization (thermal disinfection)

Pasteurization or thermal disinfection is a hot water disinfection process (minimum 71°C for at least 30 minutes), which is carried out using automatic pasteurizers or disinfector machines. The calibration of pasteurization equipment will be performed according to the manufacturer's indications. Semi-critical medical equipment/devices suitable for pasteurization include respiratory therapy and anesthesia equipment.

Advantages of pasteurization: it involves no toxicity; there is a rapid disinfection cycle; and it presents a moderate cost for machines and maintenance.

Disadvantages of pasteurization include: it can cause splash burns; the difficulty of validating the efficacy of the process; pasteurizers and related equipment can become contaminated without good preventive maintenance; and the need for careful monitoring of processes.

Pasteurization is also frequently used for washing and disinfecting linens, tableware, laboratory glassware, and instruments.