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Endoscope Care & MaintenanceHelpful Hints

Things you can do about…

• Bulging Bending Rubber

• Intermittent Video Problems

The case of the Bulging Bending Rubber

• What is it?• How bad is it?• How did that happen?• What to do?

Bulging Bending RubberWhat is it?

• Air trapped in the endoscope following leak testing expands withheat or reduced external pressure

• If bending rubber is left inflated over an extended period of time (e.g. in storage cabinet) it will be permanently stretched

• Repeated over pressurizing the scope will prematurely stretch the bending rubber

• Worn, aged bending rubber ( with time, use, heat, chemical) will also lose its elasticity

Bulging Bending RubberHow bad is it?

• Corrected early enough, there is little permanent damage to the scope. Even if a new bending rubber needs to be replaced, it’s an inexpensive repair

• Depending on how much stretching has occurred, the scope may become difficult to introduce, to angulate or to manipulate in the patient

• Left unaddressed, the bending rubber can burst unexpectedly, e.g. during shipping by air where there are large pressure changes, or during reprocessing.

• A failed bending rubber during reprocessing, especially automated reprocessing, can be catastrophic, often requiring the scope to be overhauled, a very expensive repair.

Bulging Bending RubberHow does it happen?

• Air trapped in scope following leak testing: the ETO connector was removed quickly while the air pump is still on. Correct disconnect procedure was not followed in leak testing.

• Scope shipped without ETO CAP installed: the same pressure changes that cause lotion and tooth paste to ooze out of their containers in flight, cause the bending rubber to expand. Bending rubbers have been seen to completely rupture from air shipment.

• Over pressurizing the scope: it’s easy to over-pressurize a scope using a manual leak tester. Even when the pressure needle is stopped by a stopper on the dial, continued pumping will continue to increase the scope pressure, even though the needle will not move.

• Overdue preventative maintenance: if the bending rubber looks worn, not conforming snuggly to the bending section, or buckles significant under angulation, have it replaced.

Air trapped in scope following leak testingWhat to do…

• Review instructions on the tag attached to the Leak Tester. Specifically the disconnect procedure as reproduced below…“ After test, unplug the connector from light source (or MU-1) and wait for about 30 seconds to allow air to escape from inside the scope. Then detach the cap from the scope”

• If a manual tester is being used, release air from scope BEFORE disconnecting the tester from the scope

• Double check that bending rubber is not inflated before placing scope in strorage.

• Alsways install ETO cap prior to shipping

• Install ETO cap before shipping

Shipping & Manual Leak TestingWhat to do…

• Visual inspection: Inspect the scope regularly looking for discoloration of the bending rubber, flaking, damaged or missing adhesive band, exposed thread, missing set screw at the distal tip, stretched bending rubber, etc. Early service of the bending rubber with any of these signs of wear and tear will go a long way toward reducing repair costs.

• Do not over pressurize the scope during leak testing. The scope should be pressurized to anywhere between 140mmHg minimum and 200mmHg maximum. Depending on the size of the scope this should require squeezing the bulb no more than 2 or 3 times. For large body scopes, it will require a little more pumping. The bending rubber will inflate but should not balloon.

Intermittent Video Problems

• Most annoying problem with endoscope because:– It is not always reproducible– The problem may have many different symptoms such as flickering, momentary

screen freeze, disintegrating image, green screen, flickers when scope is angulated, etc.

– It has many possible causes– A misdiagnosis, i.e. CCD problem, can translate to an very expensive and

unnecessary CCD replacement

• The check list in this article helps to reduce (hopefully eliminate) unnecessary trips back and forth to the repair facility

• The more information provided to the repair technician by the user will help speed the diagnosis process

Intermittent Video ProblemsPossible Causes

• Poor electrical contacts:

– Bent, missing pins (in pigtail, scope, light source)– Corroded dirty contacts (light source, processor)– Bad pigtail– Loose feedback cable (on pigtail)

• Cable harness in scope damaged (image flickers or freezes when scope is angulated or coiled)

• Moist or wet electrical contacts

• Loose or poor grounding

• Internal minor fluid invasion

• Thermal problems (video problem becomes more consistent as scope warms up in use)

• Damaged CCD

Intermittent Video ProblemsCheck List

Visual Inspection of connectors (light guide connector, both ends of pig tail cable, light source connector, and processor connector)

Sign of corrosionMoisture on connectorsBent, missing or otherwise damaged pinsDirty connectors

If possible, confirm that intermittent video problem does not occur with another scope (used in the same setup)

Confirm that intermittent video problem does not occur with another pigtail cable

Note if problem becomes more consistent the longer the scope isin use (a thermal problem with the electronics)

Check for poor, or loose grounding (ask biomed engineer for help with this)

Note if video problem occurs when scope is coiled or angulated

Intermittent Video ProblemsKeeping Contacts Clean

A great number of intermittent video issues result from dirty or corroded electrical contacts.

A contact cleaner spray is very effective at keeping your connectors trouble free (Caution: read manufacturer’s instructions before use)

A cotton swab is useful in drying out wet contact and clean up built up corrosion