Research: Ensuring Cavitation in a Medical Device Ultrasonic Cleaner

Background: Ultrasonic cleaners are used for fine cleaning of medical devices, removing soil from joints, crevices, lumens, and other areas that are difficult to clean using other methods. To accomplish this fine cleaning, ultrasonic cleaners use a process known as cavitation. To understand the function of the cavitation process on items that require enhanced cleaning, a study was conducted to determine whether four commercially available products claiming to test for cavitation actually detect cavitation activity. Methods: Each of the products selected for the study were placed into a Mason jar containing cleaning solution at temperatures of 77°F (25°C) and 100°F (38°C), with no cavitation energy generated. The jars were agitated by vigorous manual shaking for five seconds (one time per minute for 15 minutes) by the same operator. The results of the commercial testing products were interpreted according to manufacturers' instructions for use and recorded following the 15-minute agitation process. Each test was repeated three times. Results: Three of the four commercially available tests claiming to detect cavitation were demonstrated to not be specific to cavitation. Each of the three tests satisfied the criteria for passing when in the absence of cavitation. Conclusion: Cavitation is an important and necessary function of all ultrasonic cleaners. The results of the study clearly demonstrate that even when no cavitation is being produced, certain tests will still provide results indicating the presence of cavitation. Those tests do not distinguish between cavitation energy and the other parameters in an ultrasonic cleaner.