The cleaning and disinfecting of reusable medical instruments and devices is a crucial process in patient safety for health care facilities. Sterile processing departments are often overlooked in their importance to the entire facility, but infection preventionists need to have a working understanding of all the steps, various types of equipment involved, and potential points of risk for disease transmission that can occur.
Ultrasonic cleaners are utilized in sterile processing departments (SPD) to automate instrument cleaning. They are critical for instruments that may be challenging to manually clean effectively, such as devices with jagged edges, hinges, or serrations. The manufacturer’s instructions for use (IFU) always indicate if ultrasonic cleaning is required or appropriate for devices.
The instrument-cleaning process starts at the point of use, with the appropriate enzyme or pretreatment applied immediately after the procedure. Instruments must remain wet and transported in a rigid, closed container with appropriate biohazard labeling. Transportation to the SPD should occur immediately after the point-of-use treatment has been applied to prevent the instruments from drying. If bioburden is allowed to dry on the instruments, the cleaning becomes more challenging, potentially impacting the disinfection and sterilization steps in the process.
Once instruments are received in SPD, the decontamination process continues with rinsing, flushing, soaking, inspection, and any manual cleaning indicated by the IFUs. Then, the instruments are ready for ultrasonic cleaning. During manual cleaning, the technician must follow the care instructions for each instrument, ensuring the appropriate brushes are used, any instruments with hinges or moveable parts are opened and cleaned, and visible bioburden is removed.
Ultrasonic cleaners create ultrasonic sound waves to cause cavitation and remove bioburden.1 Cavitation is the process by which microscopic bubbles in the detergent grow and implode, causing the release of tissue and contaminants from the instrument surface.2 This process allows the effective cleaning of instruments with details such as small openings and hinges that are challenging to clean manually. The microscopic bubbles can penetrate these areas and remove any remaining tissue or contamination.
For lumened instruments, ultrasonic cleaners can connect to the instruments and provide the same cavitation process for both the interior and exterior. Additionally, the flushing and rinsing steps are incorporated into the machine’s process, ensuring full cleaning of those lumened devices that are so challenging to clean manually.
The appropriate cleaning agent must be used based on the ultrasonic cleaner and instrument IFUs. The type of cleaning agent used must meet several key considerations. It must be compatible with the cavitation process, work in different types of water quality, and be nontoxic, low-foaming, and free-rinsing.1 Water temperature also impacts the cleaning agent’s effectiveness.
Personnel should receive appropriate training and competencies for the use of ultrasonic cleaners. Sterile processing staff must clearly understand their role and its importance to patient safety. All steps of the decontamination process must be completed with accuracy and attention to detail. This can be challenging when the work is repetitive and there is pressure to quickly turn over instruments for a busy operating room schedule.
Some key points that need to be covered in training include how to properly load instruments in the cleaner to ensure as much surface area is exposed, for example, with hinges open. Instruments should not be overcrowded or overweight for the cleaner. Additionally, the visual inspection of instruments for signs of damage, bioburden, staining, or pitting during the manual cleaning is important to ensure any worn or damaged instruments are removed from use.
Another consideration for the IP when thinking about ultrasonic cleaning, or any process in SPD, is the facility water management program. Water quality for reprocessing medical devices. Water quality can directly impact the ability of sterile processing to perform adequate cleaning and disinfection of instruments. The water management program must be managed by a multidisciplinary team, which includes facilities management, infection prevention, and sterile processing. Recent water quality standards have identified key areas where the water management programs need to focus and where to implement routine water quality testing.
Poor water quality can contribute to many factors that can negatively affect the patient. For ultrasonic cleaners, in particular, water hardness, temperature, bacterial and endotoxin levels, ion levels, and sedimentation would all impact the machine's effectiveness.
For example, corrosion caused by water hardness or sedimentation can contribute to the device's malfunction. If an instrument is not cleaned and disinfected, a patient could be exposed to endotoxins or microorganisms that can contribute to infection. Hardness can impact the washer device itself and leave residue on instruments.
When discussing water management, 3 types of water are important to understand: utility water, critical water, and steam.3 Utility water, which comes from the facility’s connected water supply, is typically used for initial steps in reprocessing, except for a final rinse with critical water. Critical water has been treated to remove bacteria and endotoxins, has the approved pH levels, and meets other specifications. Some ultrasonic washers may perform the final rinse automatically, and critical water would be used for that rinse. The post-wash rinse is essential to remove any residual cleaning agent and contaminants. The manufacturer’s IFUs must be reviewed for the device to ensure the appropriate water is used for each cycle.
SPD staff must maintain logs of ultrasonic cleaners’ required maintenance and quality testing. The specific machine IFUs will indicate the type of maintenance and schedules. This may include device calibration, test strips for detergent levels, or testing for protein levels. The IP should review those logs when performing rounds in SPD to ensure completeness.
Studies have compared the effectiveness of manual cleaning to ultrasonic cleaning. Most studies have found that compared to manual cleaning, ultrasonic cleaning is more effective at removing residue from instruments, particularly those that are harder to clean.2 As medical instruments become more complex, manual cleaning becomes more difficult. However, manual cleaning is still considered best practice in the first step of the decontamination process and should not be skipped over instead of ultrasonic or automated cleaning alone. Manual cleaning of larger debris is critical for the ability of the ultrasonic cavitation process to be effective.
Are there any cons to ultrasonic cleaning? The first consideration is the cost of the equipment. However, given the benefits over manual cleaning alone, that can easily be countered with a risk-benefit analysis. Second, it is important to review the IFUs for any instruments that will be placed in the cleaner. Some materials are incompatible with ultrasonic cleaning and could damage the machine or the instruments. While not a barrier, SPD staff must have the proper training and competencies on the equipment to ensure all aspects of the IFUs are adhered to.
For many IPs, sterile processing is an intimidating and challenging area to develop expertise in, especially as a novice IP who has not worked in a perioperative field. It is important for the IP to collaborate with SPD leadership, make frequent rounds in the department, talk with staff about their processes, and reach out to fellow IPs to ask questions.
References
Ultrasonic cleaners in hospitals provide an automated cleaning process for surgical instruments and support compliance with the manufacturer's instructions for use (IFUs) of those instruments. Many complex instruments have crevices or narrow lumens, which can be difficult for other washing methods, such as a washer/disinfector, to clean. Correctly performing ultrasonic cleaning requires knowledge of the equipment, cleaning chemistries, and techniques to maximize cavitation and remove soils.
Ultrasonics can be particularly useful for washing hard-to-reach areas on a medical device, including fine serrations and box lock joints. Ultrasonic cleaning is also useful on small surgical instruments, including select microsurgical and ophthalmology devices.
Ultrasonic cleaning is only one part of the complete cleaning (or decontamination) process. The cleaning process starts in the procedure room, where pre-treatment products are applied to keep surgical instruments moist. Once the instruments arrive in the sterile processing department (SPD) for decontamination, they are rinsed, and lumens are flushed. They are often soaked for an amount of time specified in the IFU. Manual cleaning uses specialized instrument cleaning brushes and cleaning chemistries to remove soils from instrument surfaces. If the device IFUs require ultrasonic cleaning, this is the next step in the decontamination process.
Ultrasonic cleaning provides the power needed to remove residual soils from intricate instruments. In sterile processing, these ultrasonic cleaners use powerful sound waves to create cavitation capable of removing residual soils from complex instruments.
Ultrasonic cleaners work based on a successful combination of three key parameters:
First, instruments are fully submerged in a cleaning solution with detergents such as Prolystica™ HP Instrument Cleaning Chemistries in a specialized basket or holder. The ultrasonic cleaner then creates high-frequency sound waves that agitate the solution.
Ultrasonic systems consist of generators and transducers. The generators produce high-frequency electrical signals, which transducers convert into vibrations to agitate the solution. Some systems mount the transducers to the bottom of the tank. Since the ultrasonic waves are coming up from the bottom of the tank, cavitation may only reach instruments in the bottom tray.
Large-capacity ultrasonic cleaners, such as the InnoWave™ Pro Sonic Irrigator, mount transducers to the sides of the tank to evenly clean multiple layers of trays.
As the ultrasonic waves pass through the solution, they create alternating high and low-pressure cycles. During the low-pressure cycle, small bubbles are formed. When the high-pressure cycle occurs, these bubbles rapidly collapse or implode in what is known as cavitation.
Goto RedCrown to know more.
The bubbles imploding across the instrument's surfaces act like scrubbers and remove contaminants from the devices' surfaces.
The solution the instruments are submerged in allows for efficient cleaning, while the use of pressurized flow can provide additional mechanical cleaning to the internal channels of lumened or cannulated medical devices.
Innowave Ultrasonic Irrigators have sonic irrigation capabilities, delivering ultrasonic energy and cavitation to reach the devices' exterior and interior. Lumen flushing facilitates the cleaning of the challenging soils within lumens, and power flushing provides a high-pressure irrigation force through lumens. This combination provides cleaning inside these hard-to-reach lumens.
Explore our Large Capacity Ultrasonic Cleaners
Typical steps for using an ultrasonic cleaner for surgical instruments include:
After the ultrasonic process, instruments must be thoroughly rinsed with critical water. Though the instruments have been cleaned and rinsed, they may still be contaminated with microorganisms. Appropriate precautions must be taken to ensure technicians are not exposed to potential pathogens left on devices. Processing in an automated washer after an ultrasonic can offer thermal disinfection to make the devices safe to handle. Always refer to the device IFU before running a device through a washer/disinfector.
Incorrect cleaning and sterilization of ophthalmic instrumentation have been linked to the formation of Toxic Anterior Segment Syndrome (TASS). TASS is an acute inflammation of the anterior chamber of the eye occurring postoperatively and has caused blindness in some patients. It occurs when foreign matter such as enzymatic cleaners, residual debris, steam chemical carryover, powder from surgical gloves, or other material is transferred to the eye during surgery.
Due to the low threshold of contaminant needed to cause TASS, ophthalmic instrumentation must undergo special processing. For example, some manufacturers require the use of treated water only instead of cleaning chemistries.
Many organizations, such as the Association for the Advancement of Medical Instrumentation (AAMI) and the Association of periOperative Registered Nurses (AORN), provide special recommendations for ophthalmic instrumentation. A common recommendation is that surgical eye instruments be cleaned in a designated area and with an ultrasonic unit dedicated to these instrument sets. A dedicated sonic is often recommended because enzymatic detergents cannot be used on these instruments, and a shared ultrasonic needs to be cleaned before use.
Beyond cleaning - selecting a suitable detergent for ultrasonic cleaning is an important consideration. The cleaning chemistry's formulation should be:
Prolystica Instrument Cleaning Chemistries go beyond cleaning to meet all these requirements.
Suitable cleaning chemistries designed for use on medical instruments (with or without enzymes) and optimized for use at lower temperatures should be used. Most ultrasonic units heat the solution to temperatures ranging between 27 °C (80 °F) and 49 °C (120 °F). Enzymatic-based chemistries are sensitive to the effects of temperature ranges. The enzymes work less efficiently or not at all at suboptimal temperatures. Ensure the enzymatic cleaning chemistry is compatible with the ultrasonic cleaner's temperature range.
The medical instrument manufacturer's written instructions should provide specific details on solutions and process conditions for cleaning various instruments. In addition, maintaining a proper level of solution in the tank is important. Low levels of solution can cause adverse effects on the cleaning process as well as the unit itself.
As noted above, cavitation is the cleaning power of ultrasonic cleaners. Conditions or materials that prevent the formation of cavitation prevent cleaning. Since sound waves pass through materials differently, the acoustical properties of the materials have a significant impact on the formation of cavitation. Materials that block or absorb sound waves and inhibit the formation of cavitation include plastics, such as polycarbonate and silicone. On the other hand, metals readily conduct sound waves, which is why metal baskets are often used to hold instrumentation.
Some materials are also not appropriate for ultrasonic cleaning, as they can be damaged:
Overloading the ultrasonic can also impede sound wave transmission, reducing cavitation and cleaning effectiveness. Weight limitations, as defined in the IFUs, must be followed. In addition to too much weight, too much gross soil within the tank can also impede the transmission of sound waves. Tissue, bone cement, and other residuals can block or absorb sound waves and reduce cavitation. Lastly, improper cleaning agents may inhibit the formation of cavitation. Avoid cleaning chemistries with excessive foaming, and only use cleaning agents specifically designed for ultrasonic cleaners.
An ultrasonic cleaner must be maintained in proper working order according to the manufacturer's IFU. Staff must perform daily maintenance, including solution changes and degassing. Larger or more complex ultrasonic cleaners may require calibration and preventative maintenance. Quality controls ensure that the process is followed, the equipment functions, and the expected outcome is achieved.
Ultrasonic Indicator – a test that provides a realistic challenge using a synthetic test soil that mimics blood and tissues found on surgical instruments can ensure that your equipment is functioning properly.
The VERIFY Ultrasonic Indicator provides an independent objective test to evaluate the ultrasonic cycle. Problems such as insufficient energy, water level, improper temperature, and degassing may impact the results.
Residual Protein Test - A residual soil analysis looks for the presence of bioburden that may remain on instruments that have completed the cleaning process. Samples collected from instrumentation are chemically evaluated, and the detection of residual protein shows can indicate that the cleaning process was not successful.
All staff using the ultrasonic cleaner should follow policies and procedures for operating an ultrasonic cleaning unit. The facility should develop policies and procedures based on the manufacturer's owner's manual and IFUs for the equipment.
Best practice in SPDs for ultrasonic cleaning must be stated in written policies and procedures, as recommended by AAMI: "The health care organization should establish policies and procedures for all methods of cleaning and decontamination of reusable items." (ANSI/ AAMI ST79: 7.2; Policies and Procedures).
Daily and preventative maintenance procedures should be in place to ensure the ultrasonic cleaning unit is in optimal working order for the expected performance. Daily maintenance procedures can be found in the manufacturer's IFUs. Some examples might include proper cleaning of the ultrasonic unit's exterior surface, internal surfaces of the tank, and the drain screen.
An ultrasonic preventive maintenance program that the facility designs should follow the manufacturer's recommendation as to how often preventive maintenance is to be performed. These regular maintenance programs should include adjustments and replacements of worn parts so that untimely or costly schedule interruptions can be avoided. The maintenance records should be available for the department, surveying bodies, facility operations, biomedical department, and maintenance department, depending on your facility's organization.
As surgical and reusable medical devices evolve in complexity, the need for proper cleaning equipment is essential to the SPD. Ultrasonic cleaners are one piece of equipment that can assist in this process.
Explore STERIS Ultrasonic Cleaners
Want more information on Medical Ultrasonic Cleaner? Feel free to contact us.