You Want to Put That Dirty Endoscope Where?

Hospitals are considering switching to ethylene oxide sterilization of endoscopes from high level disinfectants after finding that standard methods fail to adequately disinfect devices.

Endoscopies are one of the most common procedures today, especially colonoscopies which the CDC and American Cancer Society recommends that those over the age of 50 get every 10 years, and this screening is one of the reasons that deaths due to colon cancer have been falling in recent years.

There are many different types of endoscopes for different purposes, but they all consist of a rigid or flexible tube with light guides and channels through which water or tools can be passed and manipulated and tissues biopsied and removed.  These are complex instruments and the long internal channels makes them difficult to clean and consequently more hospital acquired infections have been linked to endoscopes than any other medical device.

The manufacturers specify cleaning regimes and most hospitals use a combination of manual cleaning followed by an automatic endoscope reprocessor (AER) which performs additional cleaning and high level disinfection. In addition there is no shortage of guidance on endoscope processing from professional societies and government agencies such as the SGNA, ASGE, AORNFDA, and CDC. 

Of course there are those healthcare facilities that fail to follow the procedures and infect their patients such as Piedmont Healthcare in Atlanta which had to send letters to 456 colonoscopy patients telling them to get tested for HIV, hepatitis B and hepatitis C because they routinely ‘forgot’ to disinfect their endoscopes.

However, even when the guidelines are followed, disease transmission sometimes still occurs. In January this year,  CDC investigators reported  that 91 patients at Advocate Lutheran General Hospital, Park Ridge, Illinois were identified who had an endoscopic retrograde cholangiopancreatography (ERCP) procedure with a culture-positive endoscope, even though the hospital had followed all the established procedures. Of those who responded, 46% tested positive for the contaminant NDM-producing E coli

This case was also reported in JAMA which noted that after the hospital changed its reprocessing procedure from automated high-level disinfection with ortho-phthalaldehyde (OPA) to gas sterilization with ethylene oxide (EtO), no additional case patients were identified.

In a study at the University of Pittsburgh, researchers found an increase in antibiotic-resistant infections among ERCP patients and also showed that standard disinfection methods failed to eliminate bacteria from the flexible scopes’ channels. However, when the ‘scopes were sterilized with EtO' the infections stopped. EtO is now used to clean all scopes used in gastrointestinal procedures across UPMC.

It is likely that more hospitals will switch to EtO to protect patients from becoming infected even though EtO is more expensive. Endoscopes are expensive devices, $30,000 per device is not unusual, and so facilities want to have as rapid a reprocessing cycle as possible. AERs using high level disinfectants typically have a cycle time of about half an hour, whereas the cycle time for EtO including aeration is typically ten to 15 hours. That longer cycle time translates to a much higher equipment inventory; but facilities must do what is necessary to protect their patients.

The next time you are up for an endoscopic procedure, ask how they sterilize the ‘scope. If it is not with EtO, you may want to look elsewhere.