Flexible endoscopes are complex medical devices used to visualize the inside of various body cavities. Since the humble beginning of the endoscope, which dates back to 1853, endoscopes have taken on significant technological advances having become incredibly sophisticated and complex. Proper identification, cleaning, and inspection are crucial to the reprocessing of flexible endoscopes. However, this task has become somewhat daunting in recent years and it’s important that those who are reprocessing these devices are familiar with the endoscope structure, their function, and how to identify potential safety concerns.
Endoscope Structure
The basic design of most flexible endoscopes consists of a light guide connector, umbilical or universal cord, control body, insertion tube with internal channels, and the bending section which houses the several important components.
The endoscope connects to the video processor and light source via the light guide connector. Power and light (and in more complex scopes, a suction channel, air/water channels) travel up through the umbilical cord to connect to the main control body. Located on the control body are the video remote switches, angulation controls, suction and air/water valves, and channel opening. From the bottom of the control body extends the insertion tube(the part that is inserted into the body) and at the distal end is the bending section. Located inside the insertion tube is one or more internal channels that are used for suction, inflation, irrigation, and allow access for instrumentation to be passed through to perform various procedures.
Housed in the distal end of the endoscope are multiple components that allow for the endoscope to perform its intended function. This area can consist of one or more of the following: Biopsy channel, air/water nozzle, objective lens, water jet, light guide lens, and distal end cap. During the manual cleaning process, be sure to take a close look at the distal tip and inspect for any damage. Look for any fractures or chips to the lenses, damage to the air/water nozzle, and any damage in the end cap.
Advanced Endoscopes
Some endoscopes are equipped with more advanced technology, designed to carry out specific endoscopic procedures. The duodenoscope is one such scope, consisting of a side viewing lens and a mechanical elevator that is used to maneuver medical instrumentation into hard to reach areas. In recent years there have been several occurrences involving the duodenoscope and the difficulty of cleaning around the elevator mechanism, ultimately resulting in patient infections, some of which were fatal. In response to this, many manufacturers implemented new extensive cleaning instructions and have even made some design alterations to newer endoscopes. When reprocessing a duodenoscope it is important to thoroughly inspect the elevator and closely follow the manufactures instructions, some manufacturers can have as much as 92 steps in the manual cleaning process.
Other types of advanced endoscopes include the linear and radial echoendoscopes or ultrasound endoscopes. These two endoscopes contain an ultrasound transducer at the distal end of the scope, allowing the endoscopist to detect abnormalities in the walls of or around the gastrointestinal tract. When handling these types of endoscopes, it is important to use sufficient care, as not only are these endoscopes expensive and costly to repair but the ultrasound transducer at the distal tip is particularly fragile. In addition to the ultrasound components, the linear ultrasound endoscope contains a mechanical elevator at the distal tip, which is similar to that of the duodenoscope.
Bronchoscope
Perhaps the most simplistic of the commonly used endoscopes is the bronchoscope which is used in pulmonary procedures to visualize the inside of the lungs. This endoscope is comprised of the light source connector, umbilical cord, control body, and insertion tube. Bronchoscopes typically contain only one internal channel and consists of fewer controls than their GI counterparts. Although these scopes are quite simple in terms of their function and design, the bronchoscope is often one of the most repaired endoscopes. This is due to their smaller, more fragile design. These endoscopes regularly suffer from air leaks, fluid invasion, and bite marks that result in crushed insertion tubes.
When inspecting a bronchoscope, it is important to run your fingers down the length of the umbilical cord and insertion tube, to ascertain any damage in the form of dents or puncture marks.
Leak Testing
Leak testing is not only required prior to reprocessing an endoscope, it is also the most effective way to inspect a for puncture marks or leaks. Failure to identify a leak can result in fluid invasion which can severely damage the internal components and harbor bacteria which could be transmitted to another patient. Costs to repair an endoscope with fluid invasion can cost thousands of dollars.
Endoscope Handling
Endoscopes over time will wear due to normal use and will eventually require maintenance or repair at some point. However, much of the repairs to endoscopes are 100 percent preventable. Improper use and handling are the top contributors to the damage of endoscopes. Always maintain control of the distal tip to ensure it does not become damaged during transport. Endoscopes are to always be handled with care and coiled loosely when reprocessing.
Commonly Reported Damage
Leaks:
Typically found around the bending section at the distal end of the scope, leaks are identifiable through the process of leak testing, presenting themselves as a steady stream of bubbles (wet leak testing). Damage is most commonly caused by contact with sharp objects such as needles, forceps, and other accessories used during a procedure. Other causes include bite marks from patient, careless handling, cracked housing, and stacking of scopes.
Fluid Invasion:
Indicated by improperly functioning endoscope or corrosion of components. Fluid invasion is caused by failure to properly attach water-resistant cap, puncture of sheath, cracked housing, and wet leak tester connection.
Cracked Lens & Light Guide Cover:
Indicated by distorted image or visible fracture or chip. Cracks are typically the result of careless or accidental handling involving the impact of scope tip with a hard surface.
Dents, Kinks, and Buckles:
Indicated by a flattened/abnormal appearance of the insertion tube or umbilical cord. Common causes include excessive bending, bite makes from the patient, getting caught in cabinet door, and careless handling.
Clogged Channels:
Indicated by limited to no air or water delivery. Causes include damage to air/water nozzle, chipped O-rings, and improper or inadequate cleaning resulting in channel blockage.
Control Body Damage:
Indicated by cracks in housing and damaged controls. These damages are often caused by dropping of scope, poor handling, and lying endoscopes on the angulation knobs.
The Importance of Inspection
Inspection and a general understanding of the structure and function of the endoscope is an essential part of flexible endoscope reprocessing. Damaged or improperly cleaned endoscopes can have devastating effects on the patients we care for. Failure to properly inspect an endoscope can result in injury to the patient or contraction of a bacterial infection. Regardless of high-level disinfection (HLD) or sterilization, an endoscope cannot be deemed safe for use unless thorough cleaning and inspection take place. Every patient deserves a properly functioning endoscope that has been meticulously inspected for cleanliness and function.
This article was first published in the CBSPD Criterion summer 2018 Newsletter. This article is approved for 1 CE from CBSPD. Click on the link to access the corresponding quiz.
References
The Basics of Flexible Endoscope Reprocessing, Sterile Processing University, 2ndEdition. Lebanon (NJ): Sterile Processing University, LLC, 2016
PENTAX Medical, www.pentaxmedical.com. Montvale, (NJ)
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