February 26, 2015

Are ENT Endoscopes at Risk for Infecting Patients?

Note the instrument port which is the inner channel
In the media, there have been reports of contaminated endoscopes that have been incompletely sterilized causing life-threatening infections in patients. The endoscopes that have been implicated in these unfortunate infections transferred from one patient to another are known as duodenoscopes or EGD scopes.

The main concern that patients have are whether similar (non) sterility issues are also found in endoscopes used in the ENT world. The blunt answer is no...

The EGD scopes and endoscopes used by ENT's are completely different.

To explain, let's use the analogy of a plain old drinking straw versus a chopstick. As you can imagine, cleaning both the inside and outside of a straw is heck of a lot harder than cleaning just the outside of a chopstick. An EGD scope is like a straw while an ENT scope is like a chopstick.

EGD scopes require cleaning and sterilization of not just the outside, but also the inside channel (instrument port in pic above). ENT scopes (see pic at end of article) as a general rule do not have an inside channel at all (there are the rare exceptions). They are more like a chopstick rather than a straw and as such, much easier to clean and sterilize.

As you can imagine, it is very difficult to clean and sterilize the inside channel and that's where the sterility issues have occurred with EGD scopes that is a moot point with ENT endoscopes.

In any case, because ENT scopes lack an internal channel, cleaning and sterilization is pretty straightforward. In many ENT offices, soaking in antibacterial, antiviral, and antifungal chemicals for a certain period of time is all that is necessary.  Here is one study demonstrating that soaking in such chemicals for as little as 5 minutes can achieve sterility, though most offices soak for 20+ minutes just to be on the safe side.

Table from Arch Otolaryngol Head Neck Surg. 2012;138(2):119-121
Note the absence of an inner channel/port in ENT scopes.
EGD scopes require complex machinery whose sole job is to clean the outside of the scope as well as the inside channel and may take over an hour to perform. Clearly, this standard is insufficient given patient infections from use of this type of scope.

Now, that's not to say that ENT do not use scopes that have an internal channel... we do.

But, at least in our office, whenever the occasion is required that a scope with channel is needed, we utilize sterile disposable sheaths that contain a channel that goes over the scope. These sheaths are then thrown out after every single use.

After Deadly Infections, F.D.A. Asks Device Makers About Cleaning Methods. NYT 2/25/15

Disinfection of Flexible Fiberoptic Laryngoscopes After In Vitro Contamination With Staphylococcus aureus and Candida albicans. Arch Otolaryngol Head Neck Surg. 2012;138(2):119-121. doi:10.1001/archoto.2011.1204.
Fauquier blog
Fauquier ENT

Dr. Christopher Chang is a private practice otolaryngology, head & neck surgeon specializing in the treatment of problems related to the ear, nose, and throat. Located in Warrenton, VA about 45 minutes west of Washington DC, he also provides inhalant allergy testing/treatment, hearing tests, and dispenses hearing aids.

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