Seminar discloses ‘Dirty little secrets’

The seminar, which was held on 9 February at Birmingham’s Hilton Metropole Hotel, was chaired by Graham Stanton, a senior decontamination officer at NHS Wales Shared Services Partnership – Facilities Services, who is also Chair of IHEEM’s Decontamination Technical Platform, and a member of the Institute’s Council. It was attended by 50 delegates employed in a variety of decontamination/sterilisation, estates and facilities, infection prevention, and health and safety roles. After a brief introduction, in which he drew attention to the new Choice Framework for local Policy and Procedures (CFPP) 01-01 guidance on Management and decontamination of surgical instruments used in acute care (which has recently been out for consultation, and is expected to be published very shortly as a replacement for existing HTM guidance), Graham Stanton introduced the first speaker, Dr Brian Kirk. A highly experienced Authorising Engineer (Decontamination), Dr Kirk is currently employed as technical services specialist for Sterilization and Monitoring at 3M Health Care, and is also Secretary to IHEEM’s Decontamination Technology Platform. The focus of his presentation was on the key issues for all those responsible for sterilisation and decontamination of surgical instruments, as he sought to answer the thorny question of: ‘What do we mean by clean?’ He told delegates: “When referring to decontamination, we are talking principally of three key steps: cleaning, to remove tissue and blood from the previous procedure; disinfection – usually thermal, to inactivate microbial contamination; and sterilisation – using a validated process, to deliver a defined bioburden reduction to an acceptable Sterility Assurance Level. Each of these three processes should be specified, validated, and routinely monitored for efficacy.”

 Minimising infection risk

Sterilisation’s key goal, Dr Kirk stressed, should be to minimise the risk of transmitting infection to the patient, and he explained that it was today generally agreed that, when related to surgical instruments, the term ‘sterility’ indicated a level where only one instrument in a million might typically be found to be non-sterile. Dr Kirk said great care needed to be taken before disinfection took place to ensure that instruments were properly clean, since the presence of gross tissue debris or blood on a surgical instrument could prevent attainment of sterile conditions, as microorganisms embedded in tissue debris could potentially survive the sterilisation process. He added: “Sterilisation of instruments with residual debris creates even greater challenges to further cleaning, because the tissue gets baked onto the surfaces, making them extremely difficult to remove.” Moving on to look more specifically at why cleaning, disinfection, and sterilisation of surgical instruments were critical, Dr Kirk explained that the key reason was to prevent possible localised reactions caused by residual tissue and microbial debris on the next patient, including endotoxins. Unless controlled, the latter could also, he explained, be present in the final rinse water of washerdisinfectors. Handling of instruments without sufficient care, and the necessary precautions during inspection and packing, could also transfer microorganisms, ‘with potential clinical consequences’. One of the major worries for bodies such as the Department of Health and the Health Protection Agency in recent years, the speaker explained, had been possible cross-infection with diseasepromoting proteins; it was now known that transmissible spongiform encephalopathies such as CJD and vCJD, both protein-mediated diseases that cause degradation of cerebral tissue, were transmissible via PrPsc protein transfer from patient to patient. Recent research suggested ‘extremely low’ initiating (infective) doses, with quantities as low as picograms.