Before surgical instruments can be properly sterilized, they must be completely clean. Any bioburden or residual soil left on the instruments can hide bacteria and viruses. It can block disinfection and sterilization of that part of the instrument. This, in turn, can lead to instruments that are not properly sterilized being used in surgery, and possibly result in spreading an infection.
In addition, disinfection and sterilization take longer when there are more microorganisms to kill. Ultrasonic cleaners aren’t sterilizers or disinfectors, but they are thorough and effective cleaners, cleaning at a microscopic scale that hand washing and washer-disinfectors cannot achieve.
Cavitation and enzymatic detergent
Ultrasonic cleaners work by creating microscopic bubbles in an enzymatic detergent solution in a process called cavitation. The enzymatic detergent helps with soil removal both biologically, with enzymes digesting the soil, and chemically, with the detergent surfectants lifting soils off the instruments.
Detergents for ultrasonic cleaners often contain several types of enzymes that aid in removing different types of bioburden. Ultra Clean’s Sanizyme detergent contains three types of enzymes: protease, amylase, and lipase. Protease enzymes attack proteins, while amylase enzymes work to remove starches, and lipase enzymes break down fats.
Blood and other fluids can infiltrate the hidden areas inside lumen and robotic instruments. Ultrasonic cleaners that irrigate the instruments’ lumens and other hidden areas allow the enzymatic detergent to degrade and loosen any bioburden stuck in these areas. Once loosened, the cavitation bubbles gently scrub the bioburden and fine debris away as they implode and create suction.
Brushes often can’t get into the smallest openings, but detergent and cavitation bubbles can. They can enter the smallest cracks, crevices, and joints. This, combined with the irrigation of lumened instruments cleans those instruments inside and out.
Robotic instruments a challenge
The complexities of robotic instruments pose a particularly difficult challenge. While manual scrubbing removes larger pieces of soil and debris, it is hard to get brushes into small crevices or through the interior spaces of these complex surgical instruments to thoroughly remove bioburden and smaller debris. An ultrasonic cleaner can remove bioburden and microorganisms from pulleys, hinges, joints, springs, and all the hard-to-reach areas of robotic surgical instruments.
Most medical instrument manufacturers, including Intuitive Surgical, maker of da Vinci robotic surgical instruments, recommend or require ultrasonic cleaning in their instructions for use (IFUs). They promote the use of an ultrasonic cleaner as the most effective way to clean instruments after manual cleaning has removed any large debris.
In the Ultra Clean Systems Triton series, as the detergent solution recirculates through the basin, it passes through a filter that removes any large debris. Then the solution passes over an ultraviolet light to inactivate any microbes flushed from the instruments. After the cleaning cycle is completed, a rinse cycle then washes any remaining detergent and loosened soils down the drain.