automated cleaning and disinfection.
d. If no provision is made to contain or extract irritant vapour, atmospheric
levels may be increased due to displacement of disinfectant laden air
when fluids are pumped or drained from compartments of the machine.
e. The machines, exhaust ventilation and water treatment systems are
expensive to purchase, install and maintain.
f. Excessive dilution of the disinfectant with a subsequent reduction in
potency, may occur due to the carry over of cleansing solution or rinse
g. A build-up of disinfectant will occur if the rinse water is reused. This may
transfer toxic residues to the endoscope and cause irritation of the
patient's mucosa or endoscopist's eyes. It is preferable that the rinse
water is not reused.
Some special features or performance characteristics are optional but all
machines should clean, disinfect and rinse all internal channels and external
surfaces of the range of endoscopes used in accordance with local Hospital
Infection Control Committee protocols and/or national guidelines. Instructions
and training should be given by the machine manufacturers on how to connect
the instrument to the washer/disinfector to ensure all channel irrigation. The
machine should be programmable to accommodate the disinfectant contact times
recommended by the disinfectant manufacturers, the Department of Health and
the professional societies such as the BSG. They should have also a cycle time
compatible with the workload of the unit. Other features to consider when
purchasing a machine are:
a. the number of endoscopes which can be processed simultaneously.
b. a cycle counter and fault indicator.
c. a control system for use when the disinfectant produces an irritating or
sensitising vapour. Machines are available which are able to contain
and/or condense irritant vapours or will exhaust them either directly to the
outside or adsorb them onto a carbon filter.
d. a water treatment system which prevents recontamination of processed
instruments during rinsing. Filtration using bacteria retaining filters with a
pore size of 0.2 to 0.45u is satisfactory. The use of filters can create
additional problems and users should be aware of the need for
decontamination of the filtration and water delivery system. Bacteria free
water is preferable but not essential for rinsing of gastrointestinal
endoscopes except when the endoscope is to be used for ERCP.
Bronchoscopes and invasive surgical endoscopes also require bacteria
free water. To prevent the build up of disinfectant residues it is preferable
that the rinse water is dumped at the end of each cycle.
e. a reliable, effective and simple machine disinfection cycle.
f. an air drying facility to expel fluids and dry the channels of the endoscope
at the end of a cycle.
g. a facility to irrigate the channels of the endoscope with alcohol before
h. a leak test facility.