Healthcare facilities continually struggle to determine if surgical instruments are safe for use. Unfortunately, many surgical instruments that have gone through the sterile processing procedure and determined safe for use are not safe resulting in patient infections and death. The Center for Disease Control (CDC) has suggested that these infectionsare caused by common and antibiotic-resistant bacteria, viruses, and other pathogens due to the use of unsterile surgical equipment. As such, there is a relentlesspursuit of improvement and in the selection and execution of cleaning and sterilization methods to ensure patient safety.
One of these pursuits has been the development of enzymatic cleaning solutions – cleaning solutions with enzymes added that react to attack proteins, fats, carbohydrates, and various salts that exist in blood and body fluids. These enzyme based cleaning solutions have proven to be very helpful towards improving the safety of surgical instruments when used in conventional cleaning equipment such as spray washers. However, when used with ultrasonic cleaning equipment the results have not been as favorable.
Enzymes are a broad-ranging family of proteins that play a variety of roles, including those that can be exploited during the cleaning of medical and dental devices. For example, proteases are enzymes that can facilitate the removal of residual human proteins on medical and dental equipment via proteolytic degradation. Other important examples include lipases, which remove fat, and amylases, which break down starches. In theory, enzymatic solutions could be used at two different stages during ultrasonic cleaning: during the pre-soak phase and during the cleaning phase.
The use of enzymes as a pre-soak prior to cleaning is efficacious, and the CDC has performed detailed studies comparing different methods (http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf). In addition, comparisons have revealed that the use of pre-soak solutions prior to ultrasonic cleaning results in more effective cleaning and sterilization compared with ultrasonic cleaning alone (1).
Ultrasonic cleaning systems have been used for sterile processing for many years -perhaps not as prominently as they should. Sonication allows intricate, complicated, and specialized instruments to be both cleaned and disinfected. The creation of cavitation bubbles in the bath allows for cleaning to occur on a microscopic level by taking advantage of the immense pressures and high temperatures created at the moment of implosion.Furthermore, the violent collapse of these bubbles results in the formation of hydrogen atoms and hydroxyl radicals, which combine to form hydrogen peroxide and promote oxidation reactions. Ultrasonic cleaners can be used either with water or a water-based solution alone, or with enzymatic solutions during or immediately before the cleaning procedure.
When considering the use of enzyme-based solutions during ultrasonic cleaning, it is important to note that enzymes and enzymatic solutions function best at physiological temperature (37°C) or at room temperature.Ultrasonic cleaners generate powerful cavitations and high temperatures, which are likely to denature enzymes and limit or eliminate their activitycompletely. Furthermore, the powerfulenergy forcesgenerated by sonication also denature enzymes and thereby render them useless for cleaning purposes. Consistent with this, previous studies have revealed that that there is little difference between the cleaning achieved using tap water compared with enzyme-containing ultrasonic cleaning agents.
At Sonix4 Ultrasonics, we design and manufacture ultrasonic cleaning systems using the optimum cleaning and oxidizing frequency, and adhere to scientifically peer-reviewed methods to ensure that the highest level of decontamination occurs. Ultrasonic cleaning is the most powerful, efficient and sustainable choice for sterile processing of surgical instruments. Low energy consumption, short cleaning cycles with high throughput, and elimination of environmentally negative and costly cleaning solutions save both time and money. To further increase efficiency and reduce operating costs we do not recommend the use of enzyme-based solutions during the ultrasonic cleaning cycle because of enzyme denaturation which means that the enzymes in the solution would be ineffective both during the initial cleaning stage and even more so after water recycling and repeated use.
Sonix 4 suggests a decontamination process that includes a pre-soak of instruments immediately after use in an enzymatic solution, followed by a 10 minute ultrasonic cleaning cycle at approximately 60C/140F using an environmentally friendly neutral pH cleaning solution such as Sonix 4’s Eco4, and a quick final rinse.