Cover story - advertising feature
Choosing a high-performance cleaning chemistry
Richard Bancroft, BSc (Hons), senior director scientific, at STERIS, discusses the importance of high-performance cleaning chemistries for cleaning reusable medical devices.
Temperature, time, cleaning chemistries and mechanical action, in the presence of water, are the key variables for successful cleaning. Herbert Sinner described the inter-relationship between these four variables in 1959, and his work gained widespread acceptance as Sinner’s Circle. The key aspect of Dr Sinner’s concept is that all of these variables are inter-related; a reduction in one of the variables will necessitate an increase in one or more of the other variables. It is possible to optimise the Sinner Circle variables to allow a reduction in process time, but necessitating an increase in the other variables.
Temperature Increasing temperature can improve the cleaning outcome; however, water that is too hot can coagulate or denature proteins when not in the presence of wetting agents, resulting in a marked reduction in cleaning efficacy.
Mechanical action In a washer-disinfector, mechanical action is delivered by the force of water in the
mechanical spray arms. Increasing the pump pressure to give greater impingement on the load can cause cavitation within the pump and associated reduction in pressure. The type of cleaning chemistry and increasing temperature can create or exacerbate cavitation. In addition to the efficiency reduction and noise increase, cavitation can cause equipment damage, too.
Time
Longer time can result in greater cleaning; however, we are always looking to increase efficiency in processing time. There are often unintended consequences that affect time. For example, increasing the temperature will increase total time, due to the time needed to reach the higher operating temperature.
Chemical action A cleaning chemistry is used in combination with water. While the other cycle variables also need water, which can serve as the heat transfer agent for temperature and as the mechanical action medium. There is also a consideration of water quality or purity, when combined with a
www.clinicalservicesjournal.com Volume 23 I Issue 7 I August 2024
THE CLINICAL SERVICES JOURNAL
Driving clinician-led innovation
Addressing AI bias in FemTech Advancing best practice in infection prevention
cleaning chemistry. Cleaning chemistries may contain surfactants (surface active agents) which allow bonding between a polar solvent (water), and a non-polar molecule (lipid), helping to allow dissolution. They also enhance wetting of the surface
by lowering the surface tension of the water, allowing the cleaning solution to ‘wet’ or penetrate microscopic areas of the medical devices to be cleaned. Excessive foaming can be caused by extreme hard or soft water, large amounts of soil, or if the cleaning chemistries are dosed incorrectly. This excessive foam can, in turn, impede mechanical action or cause pump/equipment damage. Also, certain conditions can cause deposition of dissolved metal ions on instrument surfaces, causing staining. Cleaning chemistries should be formulated to handle a spectrum of types/ qualities of water. This optimisation of a washing process is focused on three outcomes – cleaning efficacy, process time and device protection. We don’t compromise on the level of cleaning needed, but equally, we need to clean as quickly as possible. Increases in mechanical and chemical action can significantly reduce cycle time but recognise that increases in mechanical and chemical action may cause foaming and problems with cavitation. The cleaning chemistry may not be the only contributor to foaming, which is often caused by dissolved sodium ions in the water supply, or the presence of proteins from the load. The cleaning process should also be designed in such a way as to not reduce the useful life of devices being processed. The cleaning chemistries used in medical
6
www.clinicalservicesjournal.com I August 2024 Fig 1
device decontamination are complex formulations of a wide range of chemicals, designed to achieve the desired cleaning
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
