Decontamination: dirty little secrets

The ‘Dirty Little Secrets’ seminar, recently held in Birmingham, was chaired by Graham Stanton, a senior decontamination officer at NHS Wales Shared Services Partnership – Facilities Services, who is also Chair of the Institute of Healthcare Engineering & Estate Management’s Decontamination Technical Platform, and a member of the Institute’s Council. Graham Stanton 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. He then introduced the first speaker, Dr Brian Kirk. A highly experienced Authorising Engineer (Decontamination), Dr Kirk is currently employed as technical services specialist for sterilisation 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 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. 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.” If decontamination is not performed adequately, there is a risk to the next patient of localised reactions caused by residual tissue and microbial debris – including endotoxins. Unless controlled, the latter could also be present in the final rinse water of washer-disinfectors. 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 disease-promoting 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 suggests that ‘extremely low’ doses, at quantities as low as pictograms, can pose an infection risk.