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Decontamination and traceability of flexible endoscopes.


The risk of contamination

Cross contamination is one of the most serious complications of diagnostic flexible endoscopy and usually results from inadequate cleaning and decontamination of the flexible endoscope. There have been documented cases of respiratory infections caused by Mycobacterium chelonae and Methylobacterium mesophilicum (Kressel 2001) as well as a number of reported cases of antimicrobial-resistant Pseudomonas aeuroginosa (CDC 1991, Sorin et al 2001, Weber & Rutala 2001) and recorded transmissions of Mycobacterium tuberculosis (Weber & Rutala 2001) and Meticillin resistant Staphylococcus aureus (MRSA). There is also a potential risk of contamination from Human Immunodeficiency Virus (HIV) and Variant Creutzfeld-Jakob disease (vCJD). There have been five reported cases of the virus hepatitis although it should be noted that there has only been one reported case in the last decade (Birnie et al 1989, Bronowicki et al 1997, HPS 2005).

More recently in 2005 in Northern Ireland 100 patients had to be notified and tested for a blood-borne virus as a result of endoscopy (HPS 2005). This was due to the contamination of five endoscopes, although these endoscopes were withdrawn from use and none of these patients tested positive. This should highlight the need for proper procedures. As a result of this incident Health Protection Scotland (HPS) completed a study revealing some shocking figures showing a compliance rate of only 17% with regards to the latest government and manufacturer guidelines. This should highlight the need for policies, ensuring proper decontamination techniques. However, the incidence of these infections in relation to the number of procedures undertaken is still remarkably small. Only 96 infections were reported following bronchoscopy between 1966 and 1992 in America (Spach et al 1993) and only 1% of all nosocomial infections in the UK (MDA 2002). However, the incidence of infection may be underestimated and under reported (Health Protection Scotland 2005).


Causes of contamination

Contamination of endoscopes can occur as a result of failure in the decontamination process, improper storage of equipment or from contamination from other patients (Ayliffe 2000). Failures in the manual cleaning process include:

* Inadequate cleaning including the use of contaminated rinse water at the incorrect temperature and using an ineffectual disinfectant (Ayliffe 2000).

* Lacklustre final rinsing and drying.

* A failure to clean the more inaccessible areas of the bronchoscope, such as the hinges and light source leading to hard deposits of particulate matter.

* Damaged and deformed surfaces and perforated instrument channels.

* Parts of the scope being left unexposed to cleaning such as instrument channels (MDA 2002).

Failures in the automated cleaning process include:

* a potential failure of the automated processor device

* contamination of the steriliant container

* use of a diluted steriliant

* design faults in the automated processor

* poor choice of disinfectant

* inadequate contact time with the disinfectant.

There is also the risk of contamination of the flexible endoscope from improper storage and transportation of the flexible endoscopes in containers which are not clean and contain potential contaminants. The best way to ensure that endoscopes are properly cleaned is to follow the manufacturer's and the government's current guidelines, in particular the Health Protection Scotland review of endoscope decontamination practice in Scotland (HPS 2005).

Current guidelines

Current guidelines state that the flexible endoscope is inserted, rinsed and cleaned in warm water with an enzymatic detergent (for example Klerzyme solution--approximately 60ml for every 10 litres of water) with thorough attention being paid to the channels (they should be brushed at least three times). The flexible endoscope should be immersed in the warm water and enzymatic detergent for at least three minutes and then cleaned and rinsed (MDA 2002). The flexible endoscope should then be checked for any damage to its outer surface and leak tested before insertion in the automatic steriliser (failure to leak test the endoscope could result in damage to the flexible endoscope).


The flexible endoscope and relevant attachments are then placed in the automated processor for at least 30 minutes with a test strip to confirm that processing has occurred. When storing flexible endoscopes it is recommended that they be suspended vertically in ventilated storage cabinets to allow circulation of air and not in contact with any other flexible scopes. There should also be a clear record of the decontamination of the flexible endoscopes and an established method of traceability. Although there are no current guidelines on how such a system could be implemented.

The solutions

One of the key areas of concern in relation to the decontamination of flexible endoscopes should be staff education relating to manual cleaning and the automated decontamination process. This should minimise the risk of contamination of the flexible endoscope through improper cleaning. The education program should cover:

* the use of appropriate disinfectant agents for manual cleaning

* immersion times

* proper care and storage of the flexible endoscopes

* how to check the equipment

* how the equipment is used

* how to use the automated decontamination device

* the potential risks of contamination.

The education program at Southern General Hospital involves an extensive education and competency pack covering the above topics. Every member of staff involved with the decontamination of flexible endoscopes has to complete this program. The education program also involves a lecture given by a representative from an endoscope supply company on the recommended guidelines on the decontamination of flexible endoscopes. The education and competency package reflects current recommended practice on the decontamination of flexible endoscopes, from the relevant professional bodies and the manufacturers of the flexible endoscopes. The education package also covers the appropriate responses to equipment failure. This process should limit the amount of human error associated with the decontamination of flexible endoscopes and should also ensure that staff recognise equipment failure and address it appropriately.

In order to ensure best practice and minimise the risk of contamination, the Southern General Hospital has arranged a separate area where endoscopes are cleaned and sterilised. This should minimise the risk of cross-contamination between 'dirty' and 'clean' areas. The 'clean' area houses the automated steriliser and the storage unit for the flexible endoscopes, and the 'dirty' area has a sink and enzymatic cleanser required to manually clean the flexible endoscopes.

For transportation between departments the clean endoscopes are sealed in blue plastic containers, which have been cleaned using antimicrobial and antienzymatic cleaning agents and are only used to transport clean endoscopes. After use, contaminated endoscopes are returned to the operating department in red disposable plastic containers. The red plastic containers can be cleaned and reused using appropriate cleaning agents or, in highly infectious cases, disposed of and re-ordered. This is a cost-effective method of transport as the plastic cases are relatively inexpensive. This will minimise the risk of contamination by using only the blue boxes for clean scopes and only the red boxes for contaminated scopes. The costs of these boxes are slight compared with the costs of nosocomial infection, which can significantly prolong hospital stays.

Record keeping

Measuring the number of infections either locally or nationally is problematic, as endoscopy is not always recognised as the cause of the infection (HPS 2005). This is usually because the patient already has a high risk of infection (for example, elderly or immuno-compromised patients) and infections may not become apparent until some time after the endoscopy (MDA 2002). An effective method of traceability would ensure that as soon as a patient develops an infection, then endoscopy can be ruled out as the cause of infection. Therefore, a good traceability system should ensure that any scope can be traced back to an individual patient with relative ease. Therefore, if any post-endoscopic patient develops an infection the endoscope used on that patient can be easily traced along with the information about the decontamination process.

To assist with tracing, a local database has been designed which contains both the pre- and post-procedure cleaning and decontamination records, along with endoscope records and details of staff members involved in the cleaning process. This means that a simple search will reveal the details of all patients and decontamination records of every individual endoscope. Also each endoscope has a unique identification number, which is printed onto labels and inserted in patient's notes. Therefore, in the event of an infection, patients' notes can be checked to reveal the endoscope type and unique identifying number, and a simple database search will reveal the decontamination process, the staff involved and the previous patients' details meaning an infection history can be gathered and the cause of the infection ascertained. This should also allow nosocomial infections caused by flexible endoscopy to be recorded easily. The financial costs to the hospital for the implementation of this traceability system are minimal as it was designed internally.



In conclusion, the Southern General Hospital's ENT and Oral and Maxillofacial surgery departments have devised a process which minimises the risk of contamination from endoscopes and promotes education and traceability. This should minimise risks to patients, financial costs to the hospital and allow for easy auditing. These policies have been designed using guidelines from the government and guidelines for best practice from the endoscope company. It is recommended that all hospitals use the government guidelines and the Health Protection Scotland review (HPS 2005) explains the government guidelines succinctly and in detail.


Ayliffe G 2000 Decontamination of minimally invasive surgical endoscopes and accessories Journal of Hospital Infection 45 (2) 263-277

Birnie G, Quigley E, Clement G, Follet E, Watkinson G 1989 Endoscopic transmission of hepatitis B virus Gut 24 (17) 1-4

Bronowicki J, Venard V, Botte C, Monhoven N, Gastin I 1997 Patient-to-patient transmission of hepatitis C virus during colonoscopy New England Journal of Medicine 33 (7) 237-240

Centers for Disease Control 1991 Nosocomial Infection and Pseudoinfection from Contaminated endoscopes and Bronchoscopes Wisonsin and Missouri Morbidity and Mortality Weekly Report 40 (39) 675-678

Health Protection Scotland 2005 Review of Endoscope Decontamination Practice in Scotland: November 2004 to May 2005 Edinburgh, Health protection Scotland

Kressel A 2001 Pseudo-outbreak of Mycobacterium chelonae and Methylobacterium mesophilicum caused by contamination of an automated endoscopy washer Infection Control and Hospital Epidemology 22 (7) 414-418

Medical Devices Agency 2002 Decontamination of Endoscopes (Device Bulletin) Department of Health, London Available from: [Accessed 2 May 2007]

Spach D, Sliverstein F, Stamm W 1993 Transmission of infection by gastrointestinal endoscopy and bronchoscopy Annals of Internal Medicince 118 (2) 117-128

Sorin M, Sorana S, Mariano N, Urban C, Combest A, Rahal J 2001 Nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa following bronchoscopy associated with improper connection to the Steris 1 processor Infection Control and Hospital Epidemiology 22 (7) 409-413

Weber D, Rutala W 2001 Lessons from outbreaks associated with bronchoscopy Infection control and Hospital epidemiology Infection Control and Hospital Epidemiology 22 403-408

Angus Crawford

BSc (Hons) RGN

Staff Nurse, Maxillofacial Theatres

Southern General Hospital, Glasgow
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Author:Crawford, Angus
Publication:Journal of Perioperative Practice
Geographic Code:4EUUK
Date:Jun 1, 2007
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