Central Service - Issue 6/2007
In Search of "the Truth"
- What’s New in Standardisation: Directive Concerning Medical Devices Amended
- Surgical Instruments Design: Patient Safety First. 1st Meeting of the Dutch Association of Experts for Sterile Medical Devices Nijmegen
- Decision-Making Pathways in Europe. European Legislature by Way of Example of Medical Device Decontamination
G. Fichet*, J. Harrison, G. McDonnell:
Reduction of Risk of Prion Transmission on Surgical Devices with Effective Cleaning Processes
(Zentr Steril 2007; 15 (6): 418-437)
Prions are unique infectious agents which have been shown to be transmitted iatrogenically through contaminated devices. Device contamination and its removal/inactivation is a particular concern in the reprocessing of medical devices. Cleaning is the first step in device reprocessing and is fundamental for effective disinfection and/or sterilization. In this report we review what is currently known on the effective cleaning of prions from contaminated devices. The various international and national guidelines on reprocessing of medical devices emphasize the importance of cleaning but, in most cases, they give little advice on how this should be achieved. Only recently has there been an increasing number of reports in the literature on investigations of cleaning efficacy against prions, with some surprising findings. Further investigations have been conducted with a CE marked alkaline cleaning formulation that claims to reduce the risk of prion contamination. This formulation has been successfully shown to be effective in both in vitro and in vivo laboratory investigations, under a wide range of conditions and using various strains of prions including scrapie, BSE, CJD and vCJD. Clinical testing has also been completed, with successful cost reduction and cleaning efficacy outcomes. It is now possible that prion decontamination can be addressed as part of standard precautions for device reprocessing.
prion, decontamination, cleaning
S. Nakata*, R. Fushimi, R. Hanamura, S. Noguchi, K. Umeshita, M. Takashina, T. Kawamoto:
Interference of Blood with the Disinfectant Process Before Washing
(Zentr Steril 2007; 15 (6): 440-450)
When used surgical instruments are decontaminated by immersion in disinfectant solutions prior to cleaning, the residual protein may be modified or altered by the disinfectants and may result in the protein adhering to the instruments.
These modified proteins and their effect on instrument cleaning were investigated by mixing blood with various disinfectant solutions and by using TOSI® cleaning indicators to identify obstacles to removal of the residual protein following immersion of the indicators in the various disinfectant solutions.
After whole human blood and each disinfectant were added to a test tube and mixed, the mixture was centrifuged. The TOSI indicators were immersed in the various disinfectant solutions for 20 minutes and then cleaned using either a washer disinfector or an ultrasonic washer.
When blood was mixed with the disinfectants and centrifuged, the protein in the blood was altered and a gel or precipitate was formed. Protein from the TOSI indicators that was also modified after immersion in the disinfectants and remained on the indicators despite the effect of cleaning by the washer disinfector or ultrasonic washer.
These findings suggest that disinfectants used before cleaning may interfere with the proper cleaning of surgical instruments. It is therefore recommended that surgical instruments be cleaned in a centralized cleaning department without the use of disinfectants prior to cleaning.
disinfection, cleaning, blood, interference
AFS Working Group:
Control and Testing of the Sterilisation Environment. Recommendation by the French Sterilisation Association AFS - Part 3
Quality Management in the CSSD - Standard Surgical Instruments (6):
Visual Inspection, Maintenance and Functional Testing of Standard Ring Needle Holders
RECOMMENDATIONS BY THE QUALITY TASK GROUP (AK »QUALITÄT«)
Requirements for Construction or Conversion of a Hospital Central Sterile Supply Department Part 2 - Staff and Material Routes