Instruments may be precleaned in one of three ways: hand scrubbing, ultrasonic cleaning, and instrument washing machines.
Ultrasonic Cleaning
Ultrasonic cleaners are used to loosen and remove debris from instruments. These cleaners also reduce the risk of hand injuries from cuts and punctures during the cleaning process (Procedure 8-1).
Puncture-resistant utility gloves, a mask, protective eyewear, and a protective gown should always be worn when the ultrasonic cleaner is used. To further limit contact with contaminated instruments, keep a set of tongs near the ultrasonic unit for removing instruments after the cleaning cycle (Figure 8-5).
The ultrasonic cleaner works by producing sound waves beyond the range of human hearing. These sound waves, which can travel through metal and glass containers, cause cavitation (formation of bubbles in liquid). The bubbles, which are too small to be seen, burst by implosion (bursting inward, the opposite of an explosion). The mechanical cleaning action of the bursting bubbles combined with the chemical action of the ultrasonic solution removes the debris from the instruments.
Instruments should be processed in the ultrasonic cleaner until they are visibly clean. The time may vary from 5 to 15 minutes, depending on the amount and type of material on the instruments, and the efficiency of the ultrasonic unit. Instruments in plastic or resin cassettes require slightly longer cleaning times because the cassette material absorbs some of the ultrasonic energy.
You should use ultrasonic solutions that are specially formulated for use only in the ultrasonic cleaner. Some ultrasonic cleaning products have enzyme activity (Figure 8-6). Other ultrasonic cleaning products have antimicrobial activity, which reduces the buildup of microbes in solutions with repeated use. Antimicrobial activity does not disinfect the instruments; it merely prevents microorganisms from increasing in number.
Do not use other chemicals such as plain disinfectants in the ultrasonic cleaner. Some disinfectants can “fix” the blood and debris onto the instruments, making subsequent cleaning more difficult. Specific ultrasonic solutions are available that remove difficult materials, such as cements, tartar, stains, plaster, and alginate (Figure 8-7). Refer to the ultrasonic unit manufacturer’s instructions regarding the specific solution to be used.
Similar to the holding solution, the ultrasonic cleaning unit should be labeled with both a chemical label and a biohazard label because it contains a chemical along with contaminated instruments.
