Jan 20, 2021 | Sterile Processing Best Practice

Don’t Trust Your Eyes When Checking Cleaning Indicators of Instruments in Washers-Disinfectors

With the widespread use of automated washers/disinfectors (WD), a lot can go wrong without a procedure in place to routinely monitor the effectiveness of your WD cleaning cycle parameters. That concern led AAMI to address this in the updating of standard ST79 in 2017.

Is the quality assurance program in your institution comprehensive and monitoring all the critical steps of medical device reprocessing?

ST79 standardizes the inspection and frequency of inspection of washers. Its recommendations cover the proper use of processing equipment at every step of processing, including criteria for setting up sterilization processing areas, staff qualifications, education, processing procedures; installation, care, and maintenance of steam sterilizers; quality control; and quality process improvement.

AAMI ST79 states that verification testing should be performed on all mechanical cleaning equipment as a part of an overall quality assurance program. “At minimum, mechanical cleaning equipment should be tested upon installation, each day it is used, when evaluating and changing cleaning solutions and after major repairs.”

That applies to all the cycles you use, too.

Like sterilizers, washers can be programmed with different cycles, for example orthopedic and standard. Each of the cycles used should be tested. Is your hospital doing that?

The presence of residual soil in instruments is an indicator of the effectiveness of your washer-disinfector. Everything from the temperature of the wash, effectiveness of washer arms, and variable cleaning in different trays within the WD should be evaluated. At fault may be the detergent, cleaning time, temperature, and function of spray arms.

If you are relying on visual inspection to determine the cleanliness of instruments, you may be missing contaminants that can be transmitted to the next patient.

There are many products and instruments available today that can quickly detect residue on medical devices. Borescopes can be used to inspect the internal channels and crevices of medical devices. Even then, microscopic contaminants may exist.

Some of the other products that can identify suboptimal cleaning are outlined in a case study from 2014 that compared three cleaning indicators to determine whether they detected residual soil due to suboptimal temperature, time, enzymatic detergent, and fluid action in a washer-disinfector. The three indicators were:

  • Pinnacle Monitor for Automated Enzymatic Cleaning Process (PNCL), which uses a dye pad put in with instruments. It changes color, based on enzymatic detergent activity, temperature, time, and mechanical activity.
  • Wash Checks (WC): a colored monitoring system that indicates when all residue is gone.
  • Test Object Surgical Instrument (TOSI), which picks up blood soil in areas not available for visual inspection.

The enzymatic detergent, cleaning time, temperature, and inactive spray arms were evaluated. The study showed that all three indicators showed more failures at 40°C compared with 60°C. Despite suboptimal cleaning cycles, all instruments looked clean. All three cleaning indicators were more sensitive to identifying soiled instruments than visual inspection.

A lot of progress has been made in monitoring and testing mechanical cleaning equipment. The advances allow for cleaning equipment to be tested daily with immediate results following cycle completion. Even then, complex instruments with crevices and lumens should be visually inspected prior to sterilization. Make sure you are attuned to your hospital’s auditing procedures and follow them.