Page 37 - Clinical Manual of Small Animal Endosurgery

Rigid Endoscopy 25

ing solutions specifically designed for endoscopes are preferred whenever
possible. Although equipment with glass fibres or lenses is not suitable
for ultrasonic cleaning, this technique can be extremely useful for hand
instruments, facilitating cleaning of hard to reach areas.
After cleaning, the equipment should be rinsed thoroughly. Working
channels, stopcocks on cannulae and all ports are flushed until clear
water runs through. Distilled or demineralised water must be used to
avoid mineral deposits that can prevent smooth operation of moving
parts; it is also important to remember not to leave instruments in
saline solution as this may cause corrosion and pitting. After cleaning,
instruments are thoroughly dried, especially optical surfaces of tele-
scopes, before sterilisation, using soft cloths for external surfaces and
compressed air or alcohol flushes for inaccessible areas. All moving
parts are lubricated according to the manufacturer’s instructions using
proprietary instrument lubricant. After lubricant has been applied, the
working parts are opened and closed and then any excess lubricant wiped
away.
Before sterilising, the equipment is inspected for damaged areas, and
telescopes and light cables are checked for light transmission. Plastic
components are inspected for discoloration, porosity and flexibility, and
instrument channels are checked for patency. Alignment of jaws of scis-
sors and grasping forceps is checked.
Instruments and telescopes may be sterilised by steam, ethylene oxide
or soaking in a chemical solution, depending on manufacturer’s recom-
mendations. Stopcocks and valves on cannulae should be left disassem-
bled for sterilisation, and ratcheting closures should be left in the open
position. This ensures that all components are exposed to the sterilising
agent or process. Instruments can be autoclaved similarly to other surgi-
cal equipment, and specialised trays are available for their sterilisation.
Telescopes, camera heads, light cables and other delicate instruments
require careful storage in padded, rigid boxes. They can be stored after
steam or ethylene oxide sterilisation, ready for the next use, or stored
non-sterile, then immersed in sterilising solutions shortly before use.
Only certain telescopes and cameras are autoclavable, and specific
cycles and temperatures may be required. However, autoclaving reduces
the life expectancy of optical devices due to heat damage, and therefore
cold sterilisation is often preferred for endoscopes. Rather than being
sterilised, the camera head is usually covered with a disposable sterile
sleeve during use. Plastic items are usually sterilised with ethylene oxide,
and some camera heads are suitable for this type of sterilisation too. The
manufacturer’s recommendations for cycle and aeration times should be
consulted. More commonly, high-level disinfection is achieved by soaking
instruments and telescopes in a proprietary disinfectant solution. The
equipment should be thoroughly cleaned after soaking by rinsing with
sterile lavage solution, as disinfectant solutions can cause significant
tissue reaction. Sterile soft cloths are then used to dry it completely;
alcohol wipes are used for lenses and glass surfaces.