Chemical apparatus and process disinfecting – deodorizing – preser – Process disinfecting – preserving – deodorizing – or sterilizing – Using disinfecting or sterilizing substance
Reexamination Certificate
1998-12-30
2003-03-18
Warden, Sr., Robert J. (Department: 1744)
Chemical apparatus and process disinfecting, deodorizing, preser
Process disinfecting, preserving, deodorizing, or sterilizing
Using disinfecting or sterilizing substance
C422S032000, C422S033000
Reexamination Certificate
active
06534002
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to systems and processes for cleaning, disinfecting, and sterilizing medical devices that have inner channels or chambers, particularly endoscopes.
Medical instruments have traditionally been sterilized or disinfected using either heat, such as is provided by steam, or a chemical in liquid, gas, or vapor state. Prior to sterilization or disinfection, the instruments to be treated are usually first cleaned. After sterilization or disinfection with a liquid chemical germicide, sterile water is used to rinse the instruments, and then the instruments are dried.
Endoscopes are flexible or rigid tubes having a multiplicity of endings. Within a any given endoscope, there may be multiple channels, or lumens. These channels serve distinct purposes. They allow for suction; the placement of instruments for biopsy, fulguration, or electrocautery by a physician; or the flow of liquid, air, or carbon dioxide (CO
2
) gas into a body cavity. Merely soaking endoscopes in a sterilant or detergent is unacceptable, since numerous pockets exist within the tubing where the sterilant or detergent cannot reach effectively. This leaves areas of contamination within the endoscope. With the prevalence of contagious diseases, such as hepatitis B, hepatitis C, and human immunodeficiency virus (HIV), sterilization or disposal of medical instruments is critical.
After use, endoscopes are sometimes discarded due to the difficulty in cleaning and sterilizing the endoscope before subsequent use. Endoscopes are very expensive, and their disposal after one use is wasteful because the structural and mechanical integrity of the endoscope has not been compromised, only its cleanness.
Traditionally, the channels inside endoscopes have been cleaned by attaching the ends of the channels to connectors and then pumping cleaning solution through the channels. U.S. Pat. No. 4,579,598 to Sasa, et al., discloses one such method of cleaning endoscopes using connectors. One problem with using connectors is that the interface between the connector and the endoscope is not exposed to the flow of cleaning solution. As a result, these interfaces are not fully cleaned. Another problem with cleaning systems that use connectors is that only the endoscope channels can be cleaned, and not the exterior surface of the endoscope. Furthermore, some endoscopes, such as those used for endoscopic surgery, need not only to be cleaned but also sterilized. Traditional systems that use connectors for cleaning endoscopes do not sterilize the endoscope.
One system for cleaning both the inside channels and the outside surfaces of an endoscope involves placing the endoscope into a container, and then allowing fluid that has been introduced into the container to flow around the endoscope and through its channels. U.S. Pat. No. 5,711,921 to Langford discloses a “surging” method for cleaning endoscopes in this fashion. This method involves placing an endoscope into a container, which is divided into two chambers by a partition. Fluid flows back and forth, or surges, between these chambers by alternating the pressure in the chambers, such that while fluid pressure increases in the first chamber, fluid pressure decreases within the second chamber, and vice versa.
One significant problem with this surging mechanism for cleaning endoscopes results from the fact that endoscope channels often have different diameters at their opposite ends. As fluid flows from the larger-caliber end of an endoscope channel to the smaller-caliber end, particulate matter and human tissue, secretions, and excrement can become lodged in the smaller-caliber end and extremely difficult to extract.
Another problem with the surging mechanism results from the frequent change in directional flow of fluid through the channels of an endoscope. In cleaning an endoscope, debris must travel a long distance, sometimes more than 150 cm, to traverse the length of the endoscope before the debris can exit the endoscope. In surging methods of cleaning endoscopes, some fluid, debris, and air pockets may move back and forth within the endoscope channel, but never travel far enough to exit the channel before the next directional shift in flow occurs. Thus, some debris and air pockets can remain trapped in the central portion of an endoscope channel with the surging method of cleaning.
Thus, there remains a need for a method of cleaning endoscopes by flowing fluid through the endoscope channels that avoids the lodgment of material in the smaller-caliber end of endoscope channels, such as occurs with the back-and-forth flow of fluid seen with surging mechanisms.
SUMMARY OF THE INVENTION
The present invention discloses a method of cleaning an endoscope within a container, wherein fluid flows predominantly or only in one direction, from the smaller-caliber end of an endoscope channel, or lumen, to the larger caliber end. This method prevents the lodgment of particulate matter and human tissue in the smaller-caliber end of endoscope channels, and it allows fluid to flow through the entire length of all endoscope channels, to permit debris to exit the channels.
In one aspect of the present invention there is provided a method for cleaning or sterilizing a tubular device having a lumen with a smaller-caliber open end and a larger-caliber open end, and an inner surface and an outer surface. This method comprises the acts of placing the device into a container having at least one interface with an adjustable opening, which interface separates the container into two or more compartments. The device is placed across the interface with one open end of the endoscope in one of the compartments and another open end of the device in another compartment. Cleaning solution, rinse solution or chemical germicide is introduced into the container, and a flow of this fluid is generated from inside the container through the inner channel of the tubular device, from the smaller-caliber end to the larger-caliber end, to clean or sterilize the inner surface of the tubular device.
In a further aspect of the present invention, a flow of cleaning solution, rinse solution, or chemical germicide is generated from inside one of the compartments to another of the compartments, around the outer surface of the tubular device, to clean or sterilize the outer surface of the device. In another aspect of the invention, one or more of the preceding acts are repeated. In a further aspect of the present invention, the interface within the container is adjusted by adjusting an adjustable aperture or seal that varies the relative amount of exposure of the inner surface and the outer surface of the tubular device to cleaning solution, chemical germicide or rinse solution.
In another embodiment of the present invention, the method is used to treat a nonmovant device in the container.
In a further aspect of the present invention, sterilization of the tubular device is conducted under a reduced pressure. After cleaning the tubular device, a predetermined amount of chemical germicide may be left in the container, and the retained chemical germicide is vaporized under reduced pressure, in order to sterilize the device. In an alternative embodiment of the method, the sterilization is conducted by reducing the pressure in the container to a first predetermined pressure, followed by further reducing the first pressure to a predetermined second pressure. In an alternative embodiment of the method, the sterilization is conducted at a controlled pump-down rate.
In a further aspect of the present method, the container is placed into or attached to a vacuum system, for applying reduced pressure to the container. The container is then removed or detached from the vacuum system after the device is sterilized. In one embodiment, the device maintains sterility in the container after the device is sterilized. The method further comprises drying the device in the container after sterilization.
In one embodiment of the invention, the container comprises flexible material. This flexible material can be gas-permea
Jacobs Paul
Lin Szu-Min
Chorbaji Monzer R.
Ethicon Inc.
Knobbe Martens Olson & Bear LLP
Warden, Sr. Robert J.
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