Ensuring compliance with HTM01-05 has now become an essential part of the job of practice managers and principals. The adherence to protocols that ensure safe and effective cleaning and sterilisation is important but so too is a thorough understanding of why certain procedures should be followed. This understanding enables a better appreciation of how decontamination procedures serve to reduce the potential for the transmission of infections and provides a framework for practices to comply with essential quality standards.
HTM01-05 references research that indicates that a 'low level of prion contamination may theoretically be present on some instruments following contact with dental tissues' and that the risk of prion transmission exists through protein contamination of instruments.
Prion contamination is important in the face of recent evidence that suggests the prion disease marker PrPsc can accumulate in peripheral tissue, for both the variant and sporadic Creutzfeldt-Jakob Disease strains. This evidence, and the reports linking prion disease transmission through blood transfusions, has led to a rise in concern over the possibility of large numbers of sub-clinical, asymptomatic carriers of the disease being present within the standard population. Any transmission risk is compounded by the ability of the prion infectious agent to remain viable after traditional inactivation regimes such as autoclaving (121°C, 30 minutes) or the use of chemical solutions.
HTM01-05 suggests 'the risk of prion transmission will be usefully reduced by compliance with the decontamination procedures described in [HTM01-05], in which protocols advise that ideally all instruments should be cleaned immediately after use'.
If a practice is unable to initiate cleaning and sterilisation processes immediately after use, they must ensure the removal of all biological matter from the instruments in order to implement effective sterilisation; a process that can be severely hampered if contaminants are allowed to dry onto the instrument surface for any length of time. The effective removal of all debris from the surface of instruments is essential prior to sterilisation as the process itself will 'bake-on' any residual debris making the instrument non-sterile and therefore unable to be used.
If instruments are allowed to dry before sterilisation, removal of residual contamination can be extremely difficult, and as tissues contain salts that can discolour and cause instruments to rust if left long enough, there is an increasing likelihood of mechanical failure.
Section 3.44 of HTM01-05 recommends the pre-soaking of instruments, to help maintain a moist, humid environment which is an aid to decontamination procedures: 'Gathering evidence indicates that keeping instruments moist after use and prior to decontamination improves protein removal and overall decontamination outcomes.'
In a paper published in 2007, Lipscomb, Pinchin, Collin and Keevil found that pre-soaking instruments significantly reduced (by up to 96 per cent) prion-infected tissue contamination. In addition the same study concluded that allowing a contaminant to dry onto an instrument surface for any length of time could severely hamper its removal and thereby compromise the effectiveness of subsequent sterilisation procedures.
HTM01-05 Section 3.5 suggests 'Instruments cleaned as soon as possible after use may be more easily cleaned than those left for a number of hours before reprocessing. Where this is not possible, water immersion or the use of a foam spray intended to maintain a moist or humid environment are thought useful in aiding subsequent decontamination.'
Practices that require this option should look for a non-hazardous, water-based liquid that is supplied as a ready-to-use formulation. Such products are sprayed directly onto the instruments, leaving surfaces coated in liquid. This immediately starts the decontamination process, helping loosen debris, and for those products containing an integral non-drying component, prevents biological matter from becoming 'dried-on' to the instruments' surface. Once instruments are ready to be cleaned, the presoaking foam is simply rinsed away using water and cleaning and sterilisation takes place in the normal way.
Using a pre-soaking solution is a simple, yet highly effective answer to the problem of instruments that are unable to be cleaned immediately after use, making it easier for the practice to operate a fully compliant decontamination operation.
References available on request.