Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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INSTRUMENT DISINFECTION QUALITY METHODS AND DEVICES
Applicant claims the benefit of U.S. Provisional Application Serial No.
61/989,250 filed
May 6, 2014; this Application is a Continuation in Part of U.S. Application
Serial No. 14/215,397
filed March 17, 2014, which claims priority to U.S. Provisional Application
Serial No. 61/792,267,
filed March 15, 2013.
Field of the Invention
[001] This invention relates to disinfection and cleaning devices and methods
and is
more particularly directed to qualify control methods and devices for
instrument disinfection.
Background of the Invention
[002] The nature of bacteria acquired in the health care setting differs
significantly from
bacteria found in a community setting, primarily in their resistance to
antibiotic therapy.
Abundant evidence exists, however, that the hospital environment itself
contributes to the
problem by harboring virulent strains of bacteria, fungi, and viruses, and
that many disinfection
methods commonly used are ineffective and may actually spread contaminants.
These
contaminants are present on objects used in the health care setting, and in
particular, on
medical devices or instruments. These instruments must be decontaminated
between uses.
[003] Many medical devices are reusable after decontamination. Along with such
materials pathogens and other contaminants are introduced. Endoscopy involves
looking inside
the body. Many of these devices have lumens and other channels or passages in
which blood,
tissue, and other materials are introduced during medical procedures.
Decontamination of
lumens and other channels and passages is critical, but also difficult due to
access.
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[004] Endoscopes are non-exhaustive examples of such devices. Endoscopy is a
common procedure in modern medical practices. Endoscopy involves the use of an
endoscope,
which is an instrument used to examine the interior of a hollow organ or
cavity of the body.
Endoscopes are inserted directly into an organ. Channels in endoscopes are
used to transport
medical instruments and materials, such as gasses and fluids. Tissue and
fluids from the
patient, and associated pathogens, are introduced into interior channels of
the endoscope
during such procedures. These devices must be decontaminated between uses.
[005] Examples of such devices are flexible and rigid endoscopes. Endoscopes
are
used to examine and surgically manipulate the sinus cavities, upper and lower
gastrointestinal
tracts, lung fields, larynx, and intra-abdominal spaces. Endoscopes may have
interior channels
or conduits that are difficult to reach and disinfect. Relatively
straightforward methods exist to
disinfect endoscopes, although the working life of the endoscopes is lessened
by washing due
to chemical degeneration of components of the endoscope. An ongoing problem
has been the
reliable disinfection of endoscopes that have interior channels. Channels are
used to inject
liquid irrigants, suction, and to pass flexible instruments such as biopsy
forceps. Interior
channels and chambers have represented a challenge to infection control
efforts.
[006] Ultraviolet irradiation, particularly in the C bandwidth (2537
Angstroms), when
given in adequate doses is lethal to all known pathogens. Microbes are
uniquely vulnerable to
the effects of light at wavelengths at or near 2537 Angstroms, due to the
resonance of this
wavelength with molecular structures. For the purposes of this document, the
term UV-C is used
for a wavelength of light being utilized for its germicidal properties, this
wavelength being in the
region of 2537 Angstroms.
[007] The United States Food and Drug Administration and the United States
Center
For Disease Control and Prevention define disinfection as the use of a
chemical procedure that
eliminates virtually all recognized pathogenic microorganisms but not
necessarily all microbial
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forms (e.g., bacterial endospores) on inanimate objects. There are three
levels of disinfection:
high, intermediate, and low. High-level disinfection kills all organisms,
except high levels of
bacterial spores, and is effected with a chemical germicide cleared for
marketing as a sterilant
by the Food and Drug Administration. Intermediate-level disinfection kills
mycobacteria, most
viruses, and bacteria with a chemical germicide registered as a
"tuberculocide" by the
Environmental Protection Agency (EPA). Low-level disinfection kills some
viruses and bacteria
with a chemical germicide registered as a hospital disinfectant by the EPA.
For the purposes of
this document, "disinfection" includes all three of these levels.
Summary of the Invention
[008] The present invention provides devices and methods for defining a data
set,
referred to herein as a signature, for a particular medical device or other
instrument having
interior channels. A baseline signature is established for the particular
device while the
particular device is known to be in a decontaminated condition. After use of
the device and
subsequent decontamination of the device, a signature for the particular
device is determined
and compared with the baseline signature to verify that the latter signature
is within an
acceptable range. The device may be a medical device, and may be an endoscope.
Brief Description of the Drawings
[009] Figure 1 is a perspective view of a medical device having interior
channels.
[010] Figure 2 is a front elevation of an exemplary device for producing
disinfection
and/or disinfection quality control according to an embodiment of the
invention.
[011] Figure 3 is an isolation of components of a device for disinfection
quality control
according to an embodiment of the invention.
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[012] Figure 4 is a graph demonstrating energy reflectance measurements at
positions
or locations of interior channels of an instrument known to be acceptably
decontaminated.
[013] Figure 5 is a graph demonstrating comparative energy reflectance
measurements at positions or locations of interior channels of an instrument
after use and
decontamination of an instrument.
[014] Figure 6 is an exemplary energy emitter and receiver that may be fitted
to a lead
that is progressively pulled through a channel of a device.
[015] Figure 7 shows another embodiment of an exemplary energy emitter and
receiver that may be fitted to a lead that is progressively pulled through a
channel of a device.
[016] Figure 8 is a schematic of an embodiment of the device according to the
invention.
Description of Preferred Embodiments
[017] Figure 1 shows a medical instrument or device 2, and specifically, an
endoscope
having interior channels. In the exemplary embodiment shown in Figure 1, the
device has three
interior channels, each having a port 50, 52, 54 that opens to an exterior of
the device. The
multiple channels of the device permit simultaneous use of a camera, one or
more medical
devices for carrying out a procedure, and/or one or more channels for
delivering or removing
fluids or gases from the body of a patient.
[018] When the medical device 2 is used in a medical procedure, the channels
become
contaminated with tissue and/or fluids from the patient. After use, the
medical device 2 is
decontaminated by known decontamination methods. Decontamination methods
include
exterior decontamination, as well as decontamination of interior channels.
[019] According to one embodiment of the present invention, an energy emitter
is
progressively transported through each of the channels. Energy is emitted from
the emitter as it
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progressively moves through the channel. Energy emission is continuous or
substantially
continuous. Energy is reflected back to a receiver that is also progressively
transported through
the channel, and preferably, simultaneously with the emitter, and at the same
rate as the
emitter, so as to measure reflectance substantially continuously along the
length of the channel.
[020] The receiver may be positioned relative to the emitter to receive
reflected energy
emitted and then reflected from interior surfaces of the channel through which
the emitter
travels. Reflectance is measured periodically, and recorded, so that there is
a reflectance
measurement that corresponds to a location of the receiver within the channel.
It is preferred
that the rate of progression of the emitter and receiver, and the number of
measurements taken,
is such that reflectance is measured substantially continuously for the entire
length of the
channel. For example, for an emitter that is transported through the channel
at the rate of 2
centimeters per second, 120 reflective measurements per second are taken so
that a reflective
measurement is taken for each 1/60 centimeter of travel.
It is preferred that a reflective
measurement is taken each 1/30 to 1/90 centimeter of travel.
[021] In one embodiment, an endoscope is placed within a housing. Figure 2. A
cable
28 conveys an emitter and receiver that communicate with a microcontroller 23.
The emitter
and receiver may communicate with an energy source and the microcontroller by
a conductor.
In a preferred embodiment, the emitter and receiver communicate with an energy
source and
the microcontroller by fiber optic material.
[022] Components of Figure 2 are shown in isolation in Figure 3. As shown in
Figure
3, the position of the receiver is a function of the angular position of the
velocity-controlled
withdrawal device 30. Reflected energy from the emitter is received by the
receiver at multiple
positions and recorded. This process is performed, and reflectance data
recorded when a
specific device that is known to have acceptable levels of decontamination
within its channels.
A new endoscope, after decontamination, but prior to use, is an example. The
first time that the
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process is performed for a known decontaminated channel may be used to
determine a
baseline signature for that specific channel, and may be repeated for each
channel of a device
to establish a baseline signature for the specific device. Reflectance as a
function of position in
the channel establishes the baseline signature for a known acceptable
decontaminated device.
[023] The baseline signature for the device is recorded and stored, for
example, by
serial number of the device. In one alternative, the device may be assigned a
particular code.
The serial number or other code is an identifier, which may be a barcode or QR
code attached
as a tag or label to the device, and which is capable of being read by an
optical scanning
device.
[024] In a preferred embodiment, after the specific device, such as endoscope
2, is
used, it is decontaminated by known processes. The process described above is
preferred to
be performed at the same energy emission levels and type of energy used in
determining the
baseline signature. Reflectance for the same locations along the length of the
channels is
measured and stored. The subsequent or later signature obtained from the
decontaminated
device is compared with the baseline signature for that specific device.
Tolerance limits, based
upon the baseline signature, are established. The tolerance limits provide
acceptable
decontamination ranges after subsequent use and decontamination.
[025] The comparison process according to an embodiment of the invention is
demonstrated graphically in Figure 4 and Figure 5. The center line 60 of each
graph
represents the base line signature for a specific channel of a specific device
that is known to be
within acceptable decontamination limits, such as a new and unused endoscope
after
decontamination. An upper limit 62 and a lower limit 64 may be established
around the baseline
signature that represent acceptable deviations from the baseline signature 60.
In most cases
deviations from the baseline signature will by indicated by lower reflected
light levels.
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[026] Figure 5 shows a comparison of a later signature taken from the same
device
after use and decontamination. The reflected energy data is compared for each
location or
position within the channel. Reflectance after decontamination is demonstrated
by line 66 of
Figure 5. The latter signature is generally within tolerance, but deviates at
a lower limit of
reflectance for a location, or linear position 68, along a channel. The
signature comparison
indicates that for a position of the channel, reflectance is outside the
established specification,
thereby indicating the possibility that foreign material present in the
channel that has not been
removed by the decontamination process.
[027] The comparison process, according to the invention, not only indicates
that the
foreign material may be present and causing a deviation in reflection, but
further, the process
provides the specific location of the foreign material that may be causing the
deviation. The
channel may be subjected to the decontamination process a second time, or
otherwise repeated
as necessary, and specific focus may be given to cleaning and decontaminating
the location
that caused the deviation.
[028] If the same reflectance data is obtained after a second attempt at
decontamination, the process may indicate a damaged channel. This will
especially be true if
the second attempt at cleaning and decontamination does not yield at least
marginal
improvement. Marginal improvement may indicate some efficacy in subsequent
decontamination or cleaning, but that cleaning is still inadequate. If less
than marginal
improvement has occurred, and the second signature is substantially the same
as the first
signature after decontamination, then physical damage to the channel may have
occurred.
[029] In one embodiment, the cable or fiber optic has a camera or lens fitted
thereon.
In the event that the latter signature shows a deviation from permitted
tolerances, the camera
can assist in determine the cause of the deviation by visually inspecting the
problem location of
the channel.
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[030] Figure 2 shows a housing for an embodiment of the device. The housing 32
is
preferred to be formed of a metal that is easy to clean, such as stainless
steel or powder coated
steel. The device may be capable of floor or wall mounting, according to the
user's preference,
and according to the overall size of the instrument or device to be
decontaminated or measured
for quality according to the process of the invention.
[031] In one embodiment, a microcontroller system 23 provides energy to the
emitter.
The microcontroller may read signals from the energy receiver, and store data
interpreted from
signals transmitted by the receiver that correlate to a position in a channel
of the device or
instrument.
[032] In use, objects, such as medical devices, which may be endoscopes 22,
may be
placed into the interior of the cabinet 32. The use of an enclosure such as
the cabinet is not
required, but is preferred to maintain a sufficiently sterile device after
decontamination. In some
embodiments, decontamination takes place in the cabinet, with the quality
control process of the
present invention performed without removing the medical device or channel 26
from the
cabinet.
[033] In an embodiment shown, a cable 28 is present in the cabinet. The cable
comprises one or more energy emitters, which may be one or more light emitting
diodes (LEDs),
and preferably, one or more receivers that detect and measure, or transmit,
reflected energy
emitted by the emitter(s) and reflected at positions of the interior channels.
After placement of
the instrument such as an endoscope into the cabinet 32, and prior to
activation of the UV-C
emitters, the user inserts the cable 28, through interior channels of the
endoscope. For
demonstration purposes of this specification, a channel 26 is shown in
isolation. The receiver is
tuned to measure the intensity of, and total dosing of, radiant energy at the
appropriate
bandwidth for the form of energy that is emitted in the channel.
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[034] The radiant energy in the form of UV-C radiation may be emitted by one
or more
LEDs located at the end of the cable in one embodiment. The cable may be
formed of an
elongated material that will transport the emitter(s) and the receiver through
the channel, and
provide current to the LED and the receiver, and a signal from the receiver to
the device as
described herein for controlling the velocity of withdrawal of the cable. The
cable may comprise
fiber optic material having that will transmit energy to be emitted, and a
signal for reflected
energy received by the receiver.
[035] In one embodiment, reflected radiation or other energy received by the
receiver(s) is read by the microcontroller system. The microcontroller
controls the rate of
withdrawal of the cable from the endoscope channel by a velocity-controlled
withdrawal device
30. Figure 8.
[036] The microcontroller system may determine the level of reflected energy
at each
location of each channel of each particular device or instrument, and store
the information
according to an identifier for the particular device or instrument, with the
information used for
later comparison according to the invention. Alternatively, the
microcontroller may transmit the
channel reflectivity information to another processor for calculation and/or
storage.
[037] In one embodiment, an energy emitting LED 33 and a receiver 34 are
positioned
at the end of the cable 28. The receiver transmits and/or measures reflected
energy emitted by
the LED. A barrier that does not permit emitted energy or radiation to pass
through may
separate the emitter from the receiver so that the receiver receives reflected
radiation but does
not receive directly emitted energy or radiation. The structure and
arrangement of the emitter
and the receiver may otherwise be such that the receiver does not directly
receive emitted
energy or radiation.
[038] Figure 7 shows an exemplary embodiment of an energy emitting LED 33 and
a
receiver 34 located in a terminal housing 36. The terminal housing is
positioned at the end of
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the cable 28. The receiver is recessed in the terminal housing so that the
receiver receives
reflected energy, but does not receive direct energy emission from the emitter
33 that is
positioned adjacent to the receiver. Reflected energy received by the receiver
34 is read by the
microcontroller system, which controls the rate of withdrawal of the terminal
housing and
attached cable from the endoscope channel with the velocity-controlled
withdrawal device 30,
which may be a servo motor.
[039] LEDs that are connected to a cable may be used in combination with fiber
optic.
The size of the channel and the material that forms the channel impacts the
properties of the
emitter and the specific type of energy that is emitted. LEDs may be larger
and capable of
providing more energy than fiber optic alone. The receiver that is local to
the emitter will also
be sized appropriately to the channel of the medical device. Alternatively,
the cable may contain
multiple emitters, such as multiple LEDs, and multiple receivers to accomplish
measured
reflectivity.
[040] The cable to which the emitter is attached for positioning the emitter
through the
channel according to this embodiment may also be used to cool the emitter,
especially in cases
where substantial energy is emitted by the device. For example, the cable may
comprise a
lumen through which cool air is transmitted to cool an emitter such as an LED.
The cable may
comprise conductive materials, which may be metal, such as copper, to conduct
heat. The
conductive material may also conduct current for powering the emitter, which
may be one or
more LEDs.
[041] After an appropriate delay to allow a steady-state output, the
microprocessor
calculates the rate of withdrawal of the cable needed to properly measure
reflectivity of the
channel being treated. The controlled withdrawal device begins to extract the
cable at the
calculated rate.
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[042] The controlled withdrawal device may comprise a geared velocity
controlled
motor connected to a rubberized soft pulley system. The controlled withdrawal
device is
designed to pull the cable at a reproducible and controlled speed without
damaging the cables.
The cable is fed into a coiling chamber located above the light source. The
rate of withdrawal of
the cable is controlled by the microprocessor and so that later measurements
are taken under
equivalent functional conditions as those pursuant to which the baseline
signature is taken.
[043] In one embodiment, one or more emitters and one or more receivers are
recessed into a terminal housing 102 in Figure 6. One end of the cable 28 is
inserted into
larger recess 104. One or more receiver(s) 106 and one or more emitters 108
may be
positioned inside of the smaller recesses. The receiver(s) read reflected
energy that is
transmitted through the channel.
[044] Energy emissions from the emitter as provided by the device may be
chosen
from bandwidths that include visible light or ultraviolet radiation or other
bandwidths that may be
emitted, received and measured as described herein. The same bandwidth will be
used for
setting the baseline signature as for subsequent testing. If disinfection is
achieved using UV-C
radiation in the channels, UV-C may be the preferred bandwidth for the quality
control method
described herein. Disinfection and quality measurement in such cases may
occur
simultaneously or substantially simultaneously.
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