Page 36 - Clinical Manual of Small Animal Endosurgery

24 Clinical Manual of Small Animal Endosurgery

pressure, compressing the vena cava, depressing venous return, and cra-
nially displacing the diaphragm, inhibiting spontaneous ventilation.
Access to mechanical ventilation is therefore recommended in animals
undergoing laparoscopy and is an absolute requirement for thoracos-
copy. Monitoring should include electrocardiography, blood pressure
monitoring, capnography and pulse oximetry. A simple oesophageal
stethoscope is also of help in such cases, as development of heart murmurs
is a feature of gas embolism. If an arterial catheter is placed, blood-gas
analysis will be facilitated and this form of monitoring is especially
helpful in prolonged procedures.
Adverse effects can also be induced by changes in body position in an
anaesthetised, dorsally recumbent patient. Inhalant anaesthetics depress
the baroreflex, thus diminishing reflex control of circulation following
changes in body posture (Joris et al., 1993; Bailey and Pablo, 1999).
The head-down tilt (Trendelenburg position) tends to decrease ventila-
tion and cardiac output, whereas the head-up tilt (reverse Trendelenburg
position) leads to reflex vasoconstriction, with increased heart rate and
blood pressure (Abel et al., 1963). Limiting the increase in abdominal
pressure to no more than 15 mmHg and the Trendelenburg angle to no
more than 15° (‘the rule of 15’) is used as a general guideline to minimise
these effects (Bailey and Pablo, 1999).

Instrument care and sterilisation

Proper care of endoscopy equipment maximises its longevity, and includes
careful cleaning, lubricating, sterilising and storing in accordance with
the manufacturer’s guidelines. It is highly recommended to train all
people using and responsible for processing the equipment in its handling
and care. All instrumentation should be cleaned immediately after use,
removing organic material from all surfaces. For example, if body fluids
are allowed to dry onto the lens of the endoscope it is difficult to clean
later without risking physical damage. Disassembly is often required for
proper cleaning of hand instruments; similarly, seals and protective caps
must be removed. Surfaces, inner cavities and jaws have to be mechani-
cally cleaned with soft brushes or sponges specifically designed for the
respective instruments. Not all the components of the kit are submersible
for cleaning, especially the less-modern telescopes and camera heads.
Pieces of equipment that are not submersible can usually be cleaned by
wiping with medical disinfectant wipes (e.g. camera lenses, light cables
and optical surfaces of telescopes). Use always a detergent approved by
the manufacturer. All the items containing optics should be handled with
particular care to prevent damage to the delicate glass fibres or lenses.
Bending and sudden impacts (e.g. dropping on to hard surfaces) are
particular hazards.
For the initial phase of cleaning commercial enzymatic cleaning solu-
tions are commonly used to clean both the scope and instruments. Clean-