Practical Gastrointestinal Endoscopy

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CHAPTER 6
nel without this being apparent. Using enzyme detergents is also
very effective in the cleaning process, including domestic nonfoaming
versions for endoscope washing machines.
Special ‘channel flushing devices’ allowing direct pressure
syringing are available from some manufacturers. A messy alternative
is to activate the regular air valve, put a finger over the
water-bottle port on the umbilical to avoid leakage, and then to
syringe through the air-input channel at the end of the umbilical
using a suitable syringe attachment, such as a micropipette
tip cut to size. If the air channel cannot be unblocked during the
process of an examination a simple dodge is to empty the water
bottle, then to activate the water valve to achieve air insufflation
(use the water syringe attachment if lens washing is needed).
The tiny angled metal ‘air pipe’ of some instruments’ tips can
need direct attack if there is an air blockage problem. First try
probing its slit-like opening, or even water-injecting this using a
fine-gauge intravenous needle. If this proves ineffective it is possible,
as a last resort, to remove the air nozzle altogether, which
usually means returning the instrument to the manufacturer’s
service department. A skilled technician can remove, clean
and reinsert the air pipe very easily. Other manufacturers have
removed this problem by introducing ingeniously designed
removable tips, allowing more thorough channel cleaning between
examinations.
Water-wash failure
Failure of the water system is unusual (other than from an empty
water-bottle), because mucus or debris do not reflux back into
the water system as easily as they do into the empty air channel.
Nonetheless, particles of rubber O-ring or other matter can become
lodged in the water system. They should be quickly cleared
by water-syringing with a micropipette tip into the small hose
that normally lies underwater within the water bottle—remembering
to press the water valve simultaneously to allow flow.
Suction failure
The suction valve itself can become obstructed, which should
be obvious on careful inspection. Particulate debris can also
block the suction channel. If in the shaft, this can be dislodged
by water-syringing through the biopsy port. Removing the suction
valve and covering the opening on the control head with
a finger is a quick way of improving suction pressure and can
result in rapid clearance of the whole system (as when sucking
polyp specimens). Applying the sucker tube directly to the suction-channel
opening can also be effective in clearing particulate
debris. As a final resort the whole suction system can be cleared
by retrograde-syringing using a 50·mL bladder syringe to wash