Simulated-use Evaluation of Flexible Endoscope Cleaning
Inoculation:
An Olympus colonoscope model CF101 type 1 (or similar device)
is the target device. To characterize the cleaning efficacy, the colonoscope
is inoculated by injecting 10 mLs of ATS containing 108 cfu/mL of
various challenge organisms into the biopsy port. The excess soil is
drained from the distal end of the scope. The scope is held at room
temperature for 30 minutes. This soiled, dried scope is then sampled before
and after complete or suboptimal manual cleaning.
Optimal Cleaning:
Complete cleaning is performed by first ensuring that the cleaning cap to
cover the electrical connections is in place. A small brush dipped in
enzymatic detergent is used to brush the cap, suction, air/water and biopsy
ports. A piece of gauze is dipped in the enzymatic detergent and then used
too wipe down the control head, the umbilical cord and finally the insertion
tube. The all-channel irrigator is attached and the scope is rinsed by
flushing 100 mLs of RO water through the channels. The scope attached to the
all-channel irrigator is then immersed in a basin containing 8 liters of
enzymatic detergent diluted as per manufacturer's instructions. The scope is
rinsed with the detergent by using the all-channel irrigator to flush 100
mLs through the channels, then allowed to soak for 2 minutes. The
all-channel irrigator is removed and while submerged, an appropriately sized
double-ended endoscope channel brush is passed twice through all the
channels including: suction port to umbilical end, suction port to distal
end and biopsy port to distal end. The all-channel irrigator is reattached
and used to flush another 100 mLs of enzymatic detergent through the
channels. The scope is immersed for a further 3 minutes at room temperature
(total enzymatic detergent contact time of 5 minutes). The scope is removed
from the enzymatic solution and the all-channel irrigator is used to flush
air to ensure that all enzyme solution is drained from the scope. The scope
is then transferred to a basin containing 8 L of RO water and 1 L of RO
water is sucked through the scope. The scope is then removed from the basin
and while still attached to the vacuum source, all excess fluid is sucked
out.
Suboptimal Cleaning:
Incomplete cleaning consists of using a non-immersion method and omitting
the brushing steps in the cleaning protocol. After soiling, a 20cc
sterile syringe is used to flush 20 mLs of tap water through the biopsy
port. Using a second 20cc syringe, 20 mLs of enzymatic solution is flushed
through the biopsy port. Finally, 40 mLs of tap water is flushed through the
biopsy port.
No Cleaning (positive control):
Samples are collected immediately after the 30 minute dry stage.
Negative Control (no soiling, no cleaning):
Baseline testing is performed by sampling the channel prior to soiling.
