Preventing Fluid Damage to the Flexible Endoscope
Introduction
Flexible endoscopes are expensive to purchase and expensive to repair. In order to maintain optimal endoscopic performance, all staff in an endoscopy lab should understand and implement best practices for cleaning and disinfecting the instruments. This online independent study activity is designed for flexible endoscopy clinicians and technicians who have the responsibility for care and handling of flexible endoscopes in their facility. The content will focus on prevention of fluid invasion and the effects of fluid invasion on endoscopes. The module will present the steps for two leak testing procedures. Finally, in the event that an endoscope requires the expertise of a repair service technician, the procedure for preparing the endoscope for transport will be presented.
Modern Endoscope Design: A Mixed Blessing
The design of the flexible endoscope design we use today has been in existence since the late 1960’s. Its silhouette has changed little but it’s been greatly improved over the years through improved image technology, superior handling for the physician, and smaller diameter insertion tubes. Video chips are replacing glass fibers as the image capturing devices and provide better imaging and documentation capabilities. Newer materials increase range of mobility for the user. Smaller components mean smaller insertion tubes for greater patient comfort.
Prior to the mid 1980s, endoscopes could not be completely immersed in fluid. The control body and light guide connector sections were not sealed enough to prevent fluid from entering and causing severe damage. So the instruments were often just wiped down with a topical solution between patients. Sometimes the insertion tubes were soaked during reprocessing but for inconsistent lengths of time. In addition, the scopes could not be pressure tested for possible leaks in internal channels or the bending section. Then came the introduction of completely immersible scopes. They could be completely soaked in appropriate solutions long enough to be classified as high level disinfected.
Thinking
Cap
Several key changes resulted in this water-resistant endoscope design that we use today. The insertion tube and bending section had always been sealed using a combination of epoxy seals and o-ring seals. Now the entire scope is assembled in this manner; anywhere two parts of a scope form a seam, an o-ring prevents fluid from entering. Epoxies (or other hard sealants) are often used when parts are threaded together. This combination of epoxy and o-rings provides a water-resistant shell to the endoscope. It is this shell that allows for total immersion.
And because the scope is now air-tight, its internal cavities can be pressurized and observed for pressure leakage. Therefore, the entire scope can be tested for potential areas of fluid invasion.
The main components of the endoscope are hollow inside to allow room for the delicate internal components. The main components include the bending section, insertion tube, control body, light guide tube and the light guide connector. The delicate internal components include the video chip and wiring assemblies, light guide fiber bundle, angle wires, biopsy/suction channels, and the air/water channels.
While the hollowness of the main structural components of the endoscope allows pressure testing to be effective, it also means that fluid entering one section of the scope can travel throughout the entire scope in a matter of minutes. Fluid entering the light guide connector, for example, may result in damage to delicate internal components throughout the scope.
And now for a Pop Quiz to test your knowledge. Try to answer the question before clicking on the bar to reveal the answer:
Next Page: Common Areas of Fluid Invasion
