What is ultrasonic cleaning?

Cleaning is the most important step in reprocessing medical devices. Disinfection and sterilization can not be carried out effectively without adequate cleaning. Ultrasonic cleaning is particularly useful for hard-to-reach areas of equipment, such as serrated or box-lock joints, but it can also gently clean precision instruments, such as microsurgery and ophthalmic equipment.

How does ultrasonic cleaning work?

The ultrasonic cleaning process uses mechanical vibration to agitate the solution to help remove dirt from the surface of the surgical instrument and, in some cases, within the lumen. The sound waves in the liquid produce tiny bubbles that implode when they come into contact with the surface, creating a vacuum-like scrubbing effect that moves the soil away from the surface; this effect is called cavitation. Then cavitation removes the biological load from the surface of the object immersed in the chamber.

The ultrasonic cleaning system uses a combination of three parameters to provide effective cleaning:

• Cavitation

• Flow/sonic irrigation

• Detergent

These correct combinations provide highly efficient cleaning systems for precision and difficult-to-clean medical equipment such as minimally invasive surgical instruments, laparoscopic equipment, and robotic surgical accessories.

Cavitation and ultrasonic cleaning machine

The effectiveness of the cavitation process depends on the design of the ultrasonic system, especially the ultrasonic frequency (in kHz) and power density.

How cavitation bubbles are created is also important. For example, older technologies use metal transducers, while newer designs use ceramic transducers that are gentler to the device. Some systems install sensors at the bottom of the tank, which can effectively remove soil from a single-layer instrument tray. As the ultrasonic wave rises from the bottom, cavitation will more effectively implode on the surface of the instrument placed on the first, most direct tray it will encounter, this is not the case for instruments placed on a second or third tray. However, the large ultrasonic cleaning machine installs the transducer on the side of the water tank, thereby effectively cleaning the multi-layer tray.

The benefits of ultrasonic cleaning

Many of the devices in today's surgical environment are complex, sophisticated, and complex in design. If there is no automatic cleaning, staff in the aseptic handling department must manually clean corners, crevices and hinges, wasting their valuable time.

Ultrasonic cleaning provides a safe and effective way to clean multiple surgical instruments at once, from precision ophthalmic and laparoscopic equipment to heavy orthopaedic equipment. The ultrasonic cleaning process allows the scrubbing action to reach small cracks, irregular surfaces, and internal passages without damaging complex equipment. Ultrasonic cleaning machines are designed to remove challenging dirt from instrument surfaces and lumen and provide consistent cleaning throughout the cleaning chamber.

Ultrasonic cleaning recommended

The ultrasonic cleaning system shall be installed, used and maintained in accordance with the manufacturer's instructions. This will include the use of specific cleansers and adherence to recommended preventive and routine maintenance.

In order to use the ultrasonic cleaning system safely and effectively, the following suggestions are given:

• Coarse (pre-cleaned) dirt should be removed from the equipment prior to the use of an ultrasonic cleaner and the brushing/flushing of the lumen.

• Surgical instrument cleaning chemicals should be designed for use in ultrasound systems

• It is generally recommended that freshly prepared cleaning solutions be degassed in accordance with the manufacturer's instructions prior to treatment of the equipment.

• The device instructions should be consulted to ensure compatibility. Because of the risk of damage to equipment components, ultrasonic treatment of certain equipment/structural materials, such as certain types of adhesives on optical components or rubber, is not recommended. Equipment containing metals such as brass, copper, aluminum, or chromium plating may not be compatible if mixed with other equipment materials, such as stainless steel.

• The cleaning solution should be changed frequently, preferably every time it is used, and always before handling ophthalmic instruments.

• It is suggested that periodic verification tests should be carried out to confirm the normal operation of the cleaning process. This will include routine maintenance and regular service maintenance, or use of clean validation instructions.