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Comparison of washer-disinfector cleaning indicators: impact of temperature and cleaning cycle parameters
Michelle J Alfa1, Nancy Olson2
1Diagnostic Services of Manitoba, Winnipeg, Manitoba, Canada; Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada; St Boniface Research Centre, Winnipeg, Manitoba, Canada.
Background:
Because automated instrument washer-disinfectors (WD) are widely used in health care to reprocess a variety of medical instruments, we developed a study to compare 3 cleaning indicators to determine whether they detected suboptimal temperature, time, enzymatic detergent, and fluid action in a washer-disinfector.
Methods:
The Miele WD was used for this comparison. One optimal cycle and 14 cycles with suboptimal enzymatic detergent, cleaning time, temperature, or inactive spray arms were evaluated. The cleaning indicators evaluated included the following: Pinnacle Monitor for Automated Enzymatic Cleaning Process (PNCL), Wash-Checks (WC), and TOSI. The scoring system for all 3 indicators was harmonized to a common scale. Soiled tweezers were included in each cycle evaluated.
Results:
The PNCL, TOSI, and WC cleaning indicators showed significantly more failures at 40°C compared with 60°C (100% vs 0% for PNCL, 17% vs 0% for TOSI, and 60% vs 22% for WC, respectively). There were significantly more failures at suboptimal temperatures with a 2- versus 4-minute cycle (100% vs 0% for PNCL, 17% vs 0% for TOSI, and 17% vs 0% for WC, respectively, for 40°C cycles). Despite suboptimal cleaning cycles, all soiled tweezers looked clean.
Conclusion:
All 3 cleaning indicators responded to suboptimal WD conditions; however, the PNCL was the most affected by alterations in the cycle conditions evaluated. In simulated use testing, cleaning indicators provided a more sensitive audit tool compared with visual inspection of soiled instruments after automated cleaning.
Insights
Three cleaning indicators (PNCL, WC, TOSI) effectively detected suboptimal conditions in automated washer-disinfectors, with PNCL showing the most sensitivity. These indicators offer a more reliable audit tool than visual inspection for reprocessing medical instruments.
Area of Science:
- Healthcare-associated infection control
- Medical device reprocessing
- Sterilization and disinfection technologies
Background:
- Automated instrument washer-disinfectors (WD) are crucial for reprocessing medical instruments in healthcare settings.
- Ensuring the efficacy of WD cycles is vital for patient safety and infection prevention.
- Suboptimal cleaning can occur due to variations in temperature, time, detergent, or fluid action.
Purpose of the Study:
- To compare the effectiveness of three cleaning indicators in detecting suboptimal conditions within an automated washer-disinfector.
- To evaluate the sensitivity of Pinnacle Monitor for Automated Enzymatic Cleaning Process (PNCL), Wash-Checks (WC), and TOSI to variations in cleaning parameters.
Main Methods:
- A Miele WD was used to evaluate one optimal cycle and 14 suboptimal cycles.
- Suboptimal conditions included variations in enzymatic detergent, cleaning time (2 vs. 4 minutes), temperature (40°C vs. 60°C), and inactive spray arms.
- Soiled tweezers were included in each cycle, and the scoring for PNCL, WC, and TOSI was harmonized to a common scale.
Main Results:
- All three indicators (PNCL, TOSI, WC) demonstrated significantly more failures at 40°C compared to 60°C.
- Suboptimal temperatures and shorter cycle times (2 minutes) led to more indicator failures.
- Despite suboptimal cleaning cycles, visual inspection of soiled tweezers showed them as clean, highlighting the limitations of visual assessment.
Conclusions:
- All evaluated cleaning indicators (PNCL, WC, TOSI) responded to suboptimal washer-disinfector conditions.
- The PNCL indicator was most sensitive to alterations in the evaluated cycle conditions.
- Cleaning indicators serve as a more sensitive audit tool for automated instrument cleaning compared to visual inspection alone.
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