Instrument Reprocessing

Based on the available medical literature, the chance that a serious infection could be acquired by undergoing endoscopy when an instrument has been processed according to established guidelines been estimated to be approximately 1 in 1,800,000.   When one considers this degree of risk in the context of the general risks and benefits of endoscopy, such as the detection of treatable diseases such as early colon cancer, and the prevention of colon cancer, medical authorities confidently accept this very low risk as acceptable.  Remember that without screening and prevention procedures, 6 of 100 Americans will develop colon cancer, a disease which is highly fatal at advanced stages.

What are the steps involved in the reprocessing of endoscopes between procedures?

Mechanical cleaning
The operating channels and external portions of the endoscope are washed thoroughly, wiped with special liquids that contain enzymes, and brushed with special cleaning instruments. Studies have shown that these steps alone can eliminate potentially harmful viruses and other microbes from an endoscope. However, much more is done before the endoscope is considered ready for use.

Leakage testing
The endoscope is tested to be sure that there are no leaks in its internal operating channels. This not only ensures peak performance of the endoscope, but also allows immediate detection of internal defects that could be a potential focus of infection within the device.

Despite its complex electronics, an entire endoscope can be submersed completely in liquid so that leakage testing can be carried out.

Use of chemical disinfectants
Next, the endoscope is soaked continuously for an appropriate time period with one of several approved liquid chemicals that destroy microorganisms which can cause infections in humans, including the AIDS virus, hepatitis viruses, and potentially harmful bacteria.

There are a variety of chemical disinfectants used to achieve high level disinfection. This process eliminates virtually all microbial life except for some inactivate dormant organisms known as spores. However, spores are uncommonly found in endoscopes and, even if present, are not harmful to humans. Although most high-level disinfectants are also sterilants (which kills all spores), this requires a much longer exposure time, and has not been shown to be necessary.

The human mouth, small intestine, colon, and rectum contain millions of non-harmful bacteria. Therefore, as soon as the endoscope touches the internal surface of patient, it is not sterile. The goal of a “sterile” endoscope from the beginning to the end of a procedure is not achievable. Therefore, the goal of reprocessing is to eliminate from the endoscope any potentially harmful microbes from the instrument. This goal can be achieved with high level disinfectant chemicals.

Rinsing and drying
After exposure to the chemical disinfectant, the endoscope channels are flushed sterile water followed by alcohol and then air dried to eliminate any moisture that could be a site of bacterial growth from the environment. The endoscope is then stored on specialized hanger to keep it dry and free of contamination.

What reprocessing system do you use at the Southwest Endoscopy Center?

Since opening our center in February 2001 we have used sophisticated computer-controlled systems for the processing of flexible gastrointestinal endoscopes.  We currently use Medivators CER Series endoscope reprocessors.  We follow instrument reprocessing guidelines published by the American Society for Gastrointestinal Endoscopy and endorsed by every major medical association dealing with endoscopy and infection control.