search.noResults

search.searching

dataCollection.invalidEmail
note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
DECONTAMINATION


In this case, the result might be hugely misleading as haemoglobin, unlike other proteins in the blood and other soft tissues, dissolves well in water. With enough time, haemoglobin dissolves and disappears from the token, even if water alone is used. What makes the problem much worse is that the remaining proteins not only stick to the surfaces firmly but are often translucent and so they are very difficult to see by the naked eye.


The 360-degree approach Most PCDs for cleaning simplify the complexity of many surgical instruments to a flat piece of material with a test soil on it. To simulate the complexity of surgical instruments, some PCDs use holders that artificially recreate challenges of narrow gaps or partial shadowing – in most cases, instruments are simplified to one surface only. This approach is problematic since spatial orientation, especially in case of automated washing, is critical since the mechanical force of jets from spray arms or even in ultrasonic washers, albeit to a smaller degree, is not distributed equally in all directions. In reality, all instruments are three dimensional, and all need to be clean everywhere – therefore, PCDs should reflect this as well.


Case study: what looks clean and is in fact not


This study was carried out as a part of the evaluation of a new range of cleaning chemicals. The first stages of the process were looking at optimisation of the process to find the cycle parameters that would clean the tags such that no proteins are detected by the protein detection dye, VeriTest Blue.


VeriTest PCDs use a natural blend of blood and homogenised tissue to represent real contamination accurately. Critically, they are composed of a mixture of water-soluble and insoluble proteins that replicate the behaviour of patients’ blood and tissue on instruments after surgery.


VeriTest AW Tags were selected as the reference tool for the study. They were loaded to a VeriTest Multi Basic block that evaluates four different surfaces at the same time (top, bottom, side and shadowing). The blood and tissue homogenate soil was selected to reflect the complex composition of the contamination on surgical instruments. VeriTest AW was developed specifically to test automated washers after instruments. Additionally, this natural test soil allows the evaluation of cleaning performance with protein detection systems. During the study, a PCD was placed in Aseptium’s Laboratory Washer Disinfector on a bespoke rack that made sure the location of the block was the same for each iteration of cycle parameters. This washer was selected for the study as its spray arms were developed to provide consistent cleaning performance, ensuring the load is cleaned all-around, from all directions. Using Aseptium’s Matrix approach for process optimisation,1


the following parameters were


proven to deliver best results. Results were analysed using protein detecting dye that


Water control cycle As a part of the study, we wanted to find out how the PCD would behave when no chemical was added to the process, in order to evaluate whether the PCD would detect a process without chemicals. Picture 3 shows the results of that process with the following cycle parameters: l Initial rinse: 2min at 25˚C l Wash: - Stage 1: 5min at 42˚C - Stage 2: 5min at 55˚C


Picture 2. Clean VeriTest PCDs after an optimised cycle and verified with VeriTest Blue.


l Rinse 1: 1min at 25˚C l Rinse 2: 1min at 25˚C


Picture 3. VeriTest AW tags after the process – magnification 2x. Dry tags left, VeriTest Blue dye right.


74 l WWW.CLINICALSERVICESJOURNAL.COM


In Picture 3, dry tags show traces of contamination, but only when observed under direct light. The change in light reflection from the surface can poentially highlight the area where proteins have adhered to the surface. However, without checking for reflections, it was very difficult – if not impossible – to see any contamination, as this layer of residual proteins is translucent. VeriTest Blue dye confirms the case and the outlines of the contaminated area are clearly highlighted in blue. The shape of the tags and the area covered by


SEPTEMBER 2020


binds to proteins and dyes them blue (Picture 2). VeriTest Blue saturates after around 30 min, so all pictures in the study were taken after 30 min exposure to the protein detection dye.


A clean result with chemicals The following represents the cycle profile used in Picture 2: l Initial rinse: 2min at 25˚C l Wash: - Stage 1: 5min at 42˚C - Stage 2: 5min at 55˚C


l Detergent was dosed at 35˚C at a concentration of 4ml/l


l Rinse 1: 1min at 25˚C l Rinse 2: 1min at 25˚C


All VeriTest AW tags used are visually clean. Visual inspection was carried under a spotlight, and results were verified with VeriTest Blue protein detection dye. No blue discolouration was noticed.


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  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92