Scope Instrument Care
Flexible and Rigid Scopes - Cleaning, Disinfection and Sterilization
Reprocessing Flexible Scopes - Evolution... and Now Revolution
Articles have been published worldwide regarding the complexity of manually reprocessing flexible endoscopes and the related concerns. Automated reprocessing and "combination" all-in-one enzymatic-detergent-complex cleaning concentrates can provide valuable alternatives and have demonstrated superior outcomes. These new developments, in automated scope cleaning and cleaning concentrates, can improve scope performance, and protect flexible scopes from damage, while reducing the risks and costs associated with manual reprocessing.
These developments have shown an increase in safety and have demonstrated a decreased risk of nosocomial infections. Endoscope manufacturers have focused on improving the functionality and clinical performance of scopes while manufacturers of washer decontaminators and washer disinfectors have focused on improving the automation of reprocessing (cleaning, disinfection, packaging, and sterilization). One main issue still remains and ongoing concern... human error. The most common human errors occur during manual cleaning and when flexible endoscopes are connected to automated endoscope re-processors (AERs). These errors occur in endoscope departments worldwide and have not been correlated to specific scopes or re-processors. Validation of these reprocessing methods and operations may be written down in Standard Operation Procedures (SOP‘s) but in fact, the verification on how close these procedures are followed may be quite difficult.
Product improvements by scope manufacturers require ongoing changes to reprocessing protocols and present new challenges to the reprocessing staff as well as the manufacturers of automated washer decontaminators and disinfectors. These ongoing changes require an ongoing review of the cleaning, disinfection and sterilization protocols. Reprocessing departments contend with daily shortages of flexible scopes that are ready to use and frequently experience FTE levels that are inadequate for manual cleaning. These factors may lead to endoscopes not being properly cleaned according to manufacturers or association recommendations. It has been found, that when a reprocessing staff is pressured for increasing the turnaround rate, cleaning may not be given the high priority necessary, due to the assumption that the sterilization to follow will provide a medical device that is safe for patient care. If an instrument is not thoroughly cleaned, it cannot be sterilized. Proper cleaning is the prerequisite for sterilization.
The German based company BHT Hygie- netechnik GmbH near Augsburg, a leading manufacturer of AER‘s for over 15 years, addressed this unsolved problem and launched (at the Medica Exhibition in November 2004) their “System CC” to the European market. The System CC received the 2005 Frost & Sullivan Award for Product Innovation. According to Frost & Sullivan: “The first and only product of it’s kind, in the world, that helps totally eliminate the need for the manual pre-cleaning of flexible endoscopes and significantly reduces the risk for patients...”. The “System CC” closes the link between Endoscope cleaning/disinfection and sterilization and greatly reduces many human error problems. The “System CC” is available either as a standalone test unit or integrated in an ergo-Logistics INNOVA E-Series AER. The ergo-Logistics washer decontaminator - washer disinfector System CC checks the flow through each endoscope channel and performs a "flow rate leak test". A reference measurement is taken for each endoscope which is used in the department or hospital and is stored together with the serial number of the endoscope. This means each single instrument will have a reference stored in the controller. The collected data includes date and time of reference taken, serial number (using the barcode reader) the flow rate through each channel and also leak test results. The advantage of making these reference measurements is that following each channel test these reference measurements can be compared and evaluated. An improper and/or forgotten connection or channel cleaning, a channel damage, biofilm build-up and endoscope leakages can easily be detected and necessary actions can been taken. Because of the outstanding sensitivity of the System CC flow rate differences of +- 10% can be detected, assuring highest safety levels for endoscopes, patients and personnel. These differences may be caused by biofilm layer build up, scratches caused by manual brushing, forgotten to brush channels and other mechanical obstructions. Picture 1 and 2 shows how channel surfaces can become scratched after several manual brushing procedures, compared to the channel surface resulting from automated cleaning.
Automated Cleaning of Rigid Scopes
Some automated Automated Washer Decontaminators and Washer Disinfectors offer an "Endoscope Pressure Box". The Pressure Box securely holds a number of Rigid Scope Heads and when closed is able to deliver the high volume low pressure cleaning fluids injected from the automated washer. The automated washer delivers the "proper sequence of treatments" (times, temperatures, cleaning concentrates, purified rinses, and hot air drying) into the Pressure Box and thoroughly cleans the scopes... inside-and-out. The washer fluid enters the scope ports and flows from proximal to the distal end of the rigid scope. Pressure Boxes are able to accommodate a wide range of scope sizes and types. The Pressure Box generates a maximum differential pressure through the optimal combination of pressure and vacuum. The Pressure Box delivers consistent predictable cleaning that provides rapid turnaround and reduces the costs and risks associated with manual cleaning. The automated cleaning of rigid and flexible scopes has proven to lengthen the usable life and improve the performance of scopes. Combination "all-in-one" cleaning concentrates (high level multi-tiered enzyme formulations in combination with a high level chemical complex of surfactants, have been shown to be more effective in preventing corrosion, removing stains, preventing hard water deposits, and removing encrusted bioburden. These neutral pH cleaning concentrates are safe for all metals, plastics, and elastic compounds.
An additional advantage using the washer decontaminator - washer disinfector pressure box is the contact free cleaning. In principle, only freely accessible surfaces can be cleaned and disinfected. The BHT washer decontaminator - washer disinfector Pressure Box avoids frictional connections and contacts on the endoscope and therefore guarantees the full efficiency of washing on all outer surfaces as well. Before and during the washing process, the endoscope is checked for leakage by overpressure sensors. High level enzymatic formulations (Enzymatic Surgical Instrument Cleaners), in combination with a high level surfactant chemical complex, have been shown to be more effective in removing stains, hard water deposits, and encrusted bioburden, while being safe to use for rigid or flexible scopes.
A pressure drop caused by leakage leads to the immediate stopping of the wash program which protects the endoscope against internal water damages. The thermal disinfection of the water for the final rinse is the safest and most easily validated method to eliminate any germs which may be in the water system. This method is performed by heating the final rinse water to a temperature of at least 93°C. Since this high water temperature would damage the endoscope it must be cooled to below 60°C where then the disinfected final rinse water can be safely be applied to the endoscope for the final rinse.
Generic Temperature Parameters for Cleaning Rigid and Flexible Scopes
Always refer to manufacturers specifications prior to establishing your reprocessing protocol.
Scopes with the HAMOU head are not suitable for reprocessing via washer decontaminators or washer disinfectors.
For the protection of scope surfaces we recommend the use of Purified Water (DI or RO de-mineralized water), at least for the final rinse treatment. A cleaning agent in neutral pH-range (less that 9) can augmented with an enzymatic cleaner. Combination all-in-one Enzymatic Surgical Instrument Cleaner detergent complexes have been shown to be highly effective. Depending on the water quality, it may be necessary to use a cleaning concentrate that softens the source water for the treatments: cold water pre-wash, detergent wash, and purified water rinse/lubrication. When the treatment processes are finished, the scopes should be removed from the reprocessor avoid corrosion.
As recommended by virtually all manfacturers of Scopes Surgical Instruments and Instrument Containers, Cleaning Concentrates (alkaline) that require a neutralizing agent (citric acid) should not be used as they can etch instrumentation. Aluminum is highly susceptible to etching. Dyed anodized aluminum parts are not easily identified as aluminum. High level enzymatic formulations (Enzymatic Surgical Instrument Cleaners), in combination with a high level surfactant chemical complex, have been shown to be more effective in removing stains, hard water deposits, and encrusted bioburden, while being safe to use for rigid or flexible scopes.
When using a Washer Decontaminator-Disinfectors Pressure Box for automated cleaning, connect the channels of optics with the insufflating channel to the rinsing connections of the washer rack. This will effectively clean the lumens and working channels while cleaning the surface of the scope.
Endoscope cleaning consists of mechanical and chemical cleaning of internal and external surfaces. This includes brushing and/or flushing of all internal channels with sterile, filtered or drinking-quality water and enzyme-detergent.
Preliminary cleaning should be started before the endoscope is detached from the light source/video processor. This will significantly reduce the overall time expended and the deterioration that results from reprocessing scopes. As soon as the endoscope has been removed from the patient, begin reprocessing, observing the following steps:
- clear gross debris by sucking detergent through the working channel (250 ml/min)
- ensure the working channel is not blocked
- irrigate the air and water channels with water checking for blockages
- expel any blood, mucus or other debris
- wipe down the insertion shaft
- check for bite marks or other surface irregularities
- detach the endoscope from the light source/video processor
- transfer the endoscope to a reprocessing room with atmospheric extraction facilities
- conduct a pressure leak test daily to check the integrity of all channels before reprocessing
The next stage involves the dismantling of detachable parts of the endoscope whereby valves and water bottle inlets are removed and detachable tips taken off the insertion tube. Rubber biopsy valve caps are discarded if breached. Water bottles and suction/air-water valves should be autoclaved.
All exposed internal and external surfaces should then be cleaned and rinsed:
- use a low-foaming enzyme-detergent specifically designated for medical instrument cleaning
- use the appropriate dilution according to the manufacturer's instructions
- flush and brush all accessible channels to remove all organic (e.g. blood, tissue) and other residues with a disposable brush-tipped wire designed for this purpose
- use brushes of the appropriate size for the endoscope channel, parts, connectors and openings; bristles should have contact with all surfaces
- repeatedly actuate the valves during cleaning to facilitate access to all surfaces
- clean the external surfaces and components of the endoscope with a soft cloth, sponge or brush
- subject reusable endoscopic accessories and endoscope components to automated washer and/or ultrasonic cleaning to remove material from hard-to-clean areas
- dispose of all cleaning items
If some of the above steps are not feasible due to limited resources, consider the following alternatives:
- use an enzymatic detergent - enzymes to remove bioburden and detergents to clean the surface
- use neutral pH water that is either: sterile, micro filtered, or (preferably) boiled.
- clean inside-and-out all surfaces and thoroughly flush all working channels
John Temple
Product Development