Proper Washer Decontaminator Washer Disinfector Design Secures Performance
The proper sequence of treatment and the correct choice of time, temperature and the components used are necessary to render surgical instruments that are critically clean, safe to handle, and have the prerequisite for sterilization. 6,7,8. Washer Decontaminators Washer Disinfectors employ a cold water pre-wash to remove gross debris. This removes proteins and lipids, preventing them from being baked onto devices during the high temperature treatments to follow. 9, 10. Then, the ultrasonic process creates millions of micro implosions to loosen and free debris from lock boxes, hinge pins, serrations and other difficult-to-access surface areas. The Washer Decontaminators Washer Disinfectors detergent wash then applies high flow low pressure water with a cleaning concentrate (at ~ 135 degrees F) in such a manner as to evenly reach all areas of the load and strip bioburden from the surgical instruments. The elevated temperature (at ~ 194 to 209 degrees F) purified water final rinse secures the biocidal process, removes mineral deposits from prior cycles and lubricates the instruments. The high temperature (at ~ 158 to 230 degrees F) dry cycle presents heated, forced air which dries each device. The critical cleaned medical devices are now clean, safe to handle, have the prerequisite for sterilization, and are properly prepared for further reprocessing. The Washington University School of Medicine at Washington University Medical Center examined the performance of a properly designed Washer Decontaminator Washer Disinfector (CESCO washer Decontaminator Model 520) and found that it removed all organisms from the surgical instruments tested. 11
The Washer Decontaminator Washer Disinfector was tested for its ability to complete remove pathological organism from surgical instruments. Pure cultures of the following organisms were grown on appropriate agar plates:
1. Staphylococcus aureus;
2. Pseudomonas aerations;
3. Escherichia coli;
4. Bacillus species
Kelly clamps, tweezers and scissors wee placed on these plates of organism, taking care to ensure that all serrated edges were packed with all the organisms. Each contaminated instrument was then dipped into the tube of Thiogycolate medium before being placed in all the washer baskets. The instruments were then processed through the complete Washer Decontaminator Washer Disinfector cycle. At the end of the drying cycle, the instruments were allowed to cool and then dipped into another tube of Thioglycolate medium.
All tubes of the Thioglycoate medium tested before the wash grew the appropriate organism within six to 18 ours after testing. All tubes tested at the end of the wash showed no growth after 14 days of incubation. This Washer Decontaminator Washer Disinfector removed all organisms from the instruments.
Washer Decontaminator Washer Disinfector delivered Disinfection 100%
Another evaluation of Washer Decontaminators Washer Disinfectors confirmed that the efficacy of disinfection was 100%. In this study, L.P. Jette and N.G. Lambert used two test methods.12 One method (N) was to test the effect of heat only within the disinfection process and the other test method (G) was to test the efficacy of both heat and washing. Each method gave reproducible results and confirmed the efficacy of the Washer Decontaminator Washer Disinfector. Washer Decontaminator Washer Disinfector Critical cleaners demonstrated the ability to completely remove pathological organisms with effective repeatability. There operation is automatic, reliable, labor saving and easy to use. Central Processing departments rarely find the need to manually treat devices and report an exceptionally low rate of rejected devices.
The Washer Decontaminator Washer Disinfector sequence, cold water pre-wash, ultrasonic cleaning, detergent washing action, final rinse and drying treatment of a properly designed Washer Decontaminator Washer Disinfector Critical Cleaner will provide critical cleaning, the prerequisite for safe handling, optimal disinfecting, and sterilizing of medical devices.
1. Peggy Ryan, RN, “Concepts of Cleaning Technologies and Processes,” Journal of Healthcare Material Management, (Nov./Dec. ’87), pp. 20-27.
2. Marimargaret Reichert, RN, “processing Reusable Medical Devices, “Journal of Hospital Material Management, p. 40.
3. Training Manual for Central Service Technicians, American Society for Central Services Personnel of the American Hospital Association, (Chicago, IL, 1986), p. 69.
4. Ryan, op. cit.
5. Training Manual for Central Service Technicians, op. cit.
6. Ryan, op. cit.
7. Interview with Charles A. Reed, Washington University School of Medicine, Washington University Medical Center, Dec. 1985.
8. L.P. Jette’and N.G.Lambert, “Evaluation of Two Hot Water Washer Disinfectors for Medical Instruments, “ Infection Control Hospital Epidemiology, Vo.1 9, No. 5, (1988), pp. 194-199.
9. Training Manual for Central Service Technicians, op. cit.
10. Ryan, op. cit.
11. Ryan, op. cit.
12. L.P. Jette’and N.G.Lambert, op.cit.
After surgical instruments and utensils were cleaned in Washers with Ultrasonic Surgical Instrument Cleaner [Washer Decontaminators, Washer Disinfectors] using a combination 4 enzyme detergent cleaning concentrate: “All surgical instruments and utensils tested were sterile at the completion of the process.”
Paper accepted for presentation at APIC:
Eighteenth Annual Conference and International Meeting
Validation of the microbial safety of surgical instruments and utensils following automated cleaning by a properly designed Washer Decontaminator Washer Disinfector Thermal Disinfection.
A. Drake, RN and L. Ayers, MD
The application of universal precautions to instruments/utensils handling became an issue in the selection of replacement decontamination equipment for Central Sterile supply at our hospital. The new technology of an automated thermal disinfection Washer Decontaminator Washer Disinfector (TW)(CESCO TM, Mercersburg, Pa.) offered increased protection to our reprocessing staff due to decreased handling but raised concerns about the efficacy of thermal disinfection as opposed to traditional washer sterilization. Because of the limited scientific documentation of this new technology, a study was undertaken to establish the microbial safety of finished products and to identify any feature or function failure which could adversely affect outcome. The sequential functions of the Washer Decontaminator Washer Disinfector progress from flush/rinse, sonic bath, wash, rinse, lubricant/deionized water (DI) sprays to drying at 240° F. for 4 minutes. The Washer Decontaminator Washer Disinfector was challenged with selected instruments and utensils that are considered to be very difficult to clean. Included were 30 each of stainless steel non-perforating towel clips and stainless steel and glass medicine cups. Each item was rinsed with a 10 5ml suspension of Staphylococcus aureus, Pseudomonsaeruginosa, Enterococcus fecalis and Candida albicans in nutrient media and then dried. The instruments wee processed in the Washer Decontaminator Washer Disinfector 3 separate loads during times of high volume operation. All products were tested for sterility. Ten separate cultures were taken of the final rinse solution of instrument lubricant and de-ionized water prior to the drying cycle. A separate culture was taken of the instrument lubricant fluid. All instruments and utensils tested were sterile at the completion of the process. The final rinse, however, was heavily contaminated with the saprophytic bacteria Flavobacterium sp., Pseudomonas (P.) picketti and P. rubrisubalbicans. The source of the contamination was determined to be resin gel in the DI tank and not the instrument lubricant. The contamination can be eliminated by the addition of a 0.22 u filter to the DI line. Our findings support the practice of validating all features of new technologies that may compromise the expected final outcome. The Washer Decontaminator Washer Disinfector is a valid replacement for the conventional washer-sterilizer.
Ultrasonic Surgical Instrument Cleaners
Optimal Ultrasonic Surgical Instrument Cleaning
and Sterilizing of Surgical Instruments