Vacuum assisted gas / vapor decontamination system having a reduced differential pressure between an interstitial space of a medical device and a decontamination chamber

Abstract

A vacuum assisted gas / vapor decontamination system having a reduced differential pressure between an interstitial space of a medical device being decontaminated and a decontamination chamber, during a sub-atmospheric decontamination process.

Description

VACUUM ASSISTED GAS / VAPOR DECONTAMINATION SYSTEM HAVING A REDUCED DIFFERENTIAL PRESSURE BETWEEN AN INTERSTITIAL SPACE OF A MEDICAL DEVICE AND A DECONTAMINATION CHAMBERCross-Reference to Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 587,573, filed October 3, 2023, entitled “VACUUM ASSISTED GAS / VAPOR DECONTAMINATION SYSTEM HAVING A REDUCED DIFFERENTIAL PRESSURE BETWEEN AN INTERSTITIAL SPACE OF A MEDICAL DEVICE AND A DECONTAMINATION CHAMBER,” which is incorporated by reference herein its entirety.Field of the Invention

[0002] The present invention relates generally to a vacuum assisted gas / vapor decontamination system, and more particularly to a vacuum assisted gas / vapor decontamination system having a reduced differential pressure between an interstitial space of a medical device being decontaminated and a decontamination chamber, during a decontamination process.Background of the Invention

[0003] Medical devices, such as certain surgical instruments, endoscopes, etc., may be re-used numerous times. Accordingly, such medical devices are subject to a decontamination process (e.g., a sterilization process) prior to re-use that is commonly referred to as “reprocessing.” Some decontamination systems use vaporized chemical sterilants or chemical gas in the sterilization process, including but not limited to, hydrogen peroxide, peracetic acid, ozone, chlorine dioxide, nitrogen dioxide, and the like.

[0004] Many typical decontamination systems include a sterilization chamber housing defining a sterilization chamber dimensioned to receive medical devices (or other articles) that are to be sterilized. A vacuum source and a venting valve are provided to modify the pressure level within the sterilization chamber in accordance with one or more control algorithms executed by a control unit. When the vacuum source is activated by the control unit, thepressure within the sterilization chamber is reduced. When the venting valve is activated (i.e., opened) by the control unit, pressure within the sterilization chamber increases as the sterilization chamber is vented to atmosphere.

[0005] The control algorithm executed by the control unit of a decontamination system typically include a plurality of operating cycles, such as a load conditioning cycle and a sterilization cycle. In the load conditioning cycle, the sterilization chamber and the medical device located therein are prepared within the sterilization chamber for optimal sterilization during the sterilization cycle. The sterilization cycle may include exposing the medical devices in the sterilizing chamber to pressurized sterilant gas, heat treatment, chemical treatment, plasma treatment, vacuum treatment, and / or other types of sterilization procedures. In an example sterilization cycle, the cycle may begin with a vacuum being applied within sterilization chamber by activation of the vacuum source in accordance with the control algorithm. The control unit determines whether a sufficient pressure level has been reached within sterilization chamber in accordance with the control algorithm. One or more pressure sensors within the sterilization chamber may provide the control unit with pressure data. Alternatively, the control unit may simply activate the vacuum source for a predetermined time period and assume that the appropriate pressure has been reached in the sterilization chamber, based upon the duration for which the vacuum source is activated.

[0006] Once the sterilization chamber reaches an appropriate pressure level (e.g., between approximately 0.2 torr and 10 torr), the control unit injects a sterilant into the sterilization chamber. The sterilant, for example, may be comprised of a vapor of an oxidizing agent, such as hydrogen peroxide, peroxy acids (e.g. peracetic acid, performic acid, etc.), ozone, or a mixture thereof. Once the sterilant has been injected into the sterilization chamber, the control unit monitors the time to determine whether a predetermined duration of time has elapsed (e.g., a few seconds to several minutes). Until the predetermined duration of time has elapsed, the sterilization chamber remains in a sealed state at the appropriate pressure level, with the applied sterilant acting upon the medical device located inside the sterilization chamber.

[0007] After the predetermined duration of time has elapsed, the control unit activates the venting valve to vent the sterilization chamber to atmosphere. In some prior art decontamination systems, the sterilization chamber may be allowed to reach atmosphericpressure, while in other versions the sterilization chamber only reaches sub-atmospheric pressure.

[0008] In the example described above, the sterilization cycle is complete after the venting process. However, in some cases, a vacuum is again applied to the sterilization chamber following the venting process, and then a plasma is applied to the sterilization chamber.

[0009] It should be understood that in prior art decontamination systems, an entire sterilization cycle may be repeated one or more times. The number of iterations may vary based on a cycle selection, which may be influenced by the particular kind of medical device being sterilized in the sterilization chamber.

[0010] As to pressure changes in the sterilization chamber during the sterilization cycle, the pressure level drops significantly and rapidly when the vacuum source is activated to apply a vacuum to the sterilization chamber. The pressure level then stays substantially constant while the sterilant is injected into the sterilization chamber and during the subsequent, predetermined duration. The pressure level then increases significantly and rapidly when the venting valve is activated to vent the sterilization chamber to atmosphere. Accordingly, the pressure within the sterilization chamber basically alternates between a relatively high pressure (i.e., atmospheric pressure) and a relatively low pressure (i.e., a vacuum state).

[0011] For certain types of medical devices, the above-described pressure changes in the sterilization chamber can result in damage to the device. One such medical device that is prone to such damage is an endoscope. A typical reusable flexible endoscope is comprised of a complex network of lumens and articulating wires separately encased within a hollow interconnected series of flexible elastomeric tubes and rigid metal / plastic housings. An interstitial space or compartment is formed between the tubes and rigid metal / plastic housings. The interstitial space is in fluid communication, and thus in equal pressure, with the atmosphere through an opening at the light guide connector end of the endoscope. Access to the interstitial space can be controlled using a valve known as a venting connector (also referred to as an EO connector), which is designed directly into a light guide connector or directly into a soaking cap of a fiberscope or videoscope.

[0012] For endoscopes where the venting connector is on the soaking cap (e.g., fiberscopes and videoscopes), venting the interstitial space may be accomplished by removingthe soaking cap or opening the venting connector valve. For endoscopes where the venting connector is located elsewhere, the interstitial space is vented by opening the venting connector valve. The venting connector valve can be opened to inject air or other gases / vapor into the interstitial space when there is a need to inflate the bending rubber portion of the insertion tube during a procedure or to test for internal seal leaks prior to reprocessing.

[0013] When reprocessing an endoscope using a sub-atmospheric decontamination process, the venting connector valve can be placed in an open position or a closed position. However, problems are encountered with both the open and closed positions, as discussed below.

[0014] If the venting connector valve is closed during sub-atmospheric processing, then the interstitial space can overpressurize, and the elastomer tubes and sealed housings could become damaged, causing a loss of seal integrity. As a result, the endoscope can be rendered unusable. It should be appreciated that closing off the interstitial space during a vacuum assisted decontamination process creates significant unequal pressures between the interstitial space of the endoscope and the decontamination chamber.

[0015] If the venting connector valve remains open during sub- atmospheric processing, the chemistry used during the sub-atmospheric gas / vapor decontamination process can enter the interstitial space and react with contents, thereby, causing the formation of substances that lead to degradation or destruction of the endoscope. For example, the interstitial space of many reusable flexible gastrointestinal (GI) endoscopes contains a dry lubricant used to reduce friction when the outer flexible tube slides over the inner lumen / wire network during assembly or repair. If permitted into the interstitial space, the chemistry used in the gas / vapor decontamination process can react with certain dry lubricants to form undesirable residues. Likewise, certain materials used only on the inside of an endoscope, or used on surfaces of materials facing the inside of the interstitial cavity of an endoscope, may not be compatible with the chemistry used during the sub-atmospheric gas / vapor decontamination process. Exposing such materials to the chemistry may accelerate the wear and degradation of the endoscope, and reduce its use life.

[0016] The present invention provides an apparatus and method that overcomes the problems discussed above.Summary of the Invention

[0017] In accordance with the present invention, there is provided a vacuum assisted gas / vapor decontamination system comprising: a decontamination chamber dimensioned to receive a medical device for sterilization, said decontamination chamber having a venting valve for increasing the pressure in the decontamination chamber; a vacuum pump for reducing pressure in the decontamination chamber; a sensing element for sensing a pressure level in the decontamination chamber; a reactive agent source for injecting a gaseous / vaporous chemical sterilant into the decontamination chamber; a reversible fluid pump operable in forward and rearward directions; a fluid line having a first end with a connector assembly adapted to fit onto a device port of the medical device to put the fluid line in fluid communication with an interstitial space of the medical device, and a second end connected with the reversible fluid pump, said reversible pump in fluid communication with an external environment outside of the decontamination chamber; and a control unit for controlling operation of the decontamination system, said control unit operable to activate the reversible fluid pump to operate in the forward direction to transfer air / gas from the interstitial space to the external environment and operable to activate the reversible fluid pump to operate in the reverse direction to inject air into the interstitial space from the external environment, wherein said control unit activates the fluid pump in the forward and reverse directions in accordance with the pressure level detected by the sensing element.

[0018] In accordance with another aspect of the present invention, there is provided a vacuum assisted gas / vapor decontamination system comprising: a decontamination chamber dimensioned to receive a medical device for sterilization, said decontamination chamber having a venting valve for increasing the pressure in the decontamination chamber; a vacuum pump for reducing pressure in the decontamination chamber; a sensing element for sensing a pressure level in the decontamination chamber; a reactive agent source for injecting a gaseous / vaporous chemical sterilant into the decontamination chamber; a double-walled container system including: (a) a rigid outer container defining an interior space, and (b) a flexible inner container located within the interior space of the outer container, said inner container defining an interior space of varying volume; a fluid line having a first end with a connector assembly adapted to fit onto a device port of the medical device to put the fluid line in fluid communication with an interstitial space of the medical device, and a second endconnected with the inner container to put the fluid line in fluid communication with the interior space of the inner container; and a control unit for controlling operation of the decontamination system.

[0019] In accordance with still another aspect of the present invention, there is provided a method for controlling the pressure differential between a decontamination chamber and an interstitial space of a medical device located in the decontamination chamber, during a vacuum assisted gas / vapor decontamination process, said method comprising: activating a reversible pump in a forward direction to evacuate air / gas from the interstitial space of the medical device into an external environment outside of the decontamination chamber, when detecting decreasing pressure in the decontamination chamber; and activating the reversible pump in a reverse direction to inject air into the interstitial space of the medical device from the external environment when detecting an increasing pressure in the decontamination chamber.

[0020] In accordance with still another aspect of the present invention, there is provided a method for controlling the pressure differential between a decontamination chamber and an interstitial space of a medical device located in the decontamination chamber, during a vacuum assisted gas / vapor decontamination process, said method comprising: connecting a flexible inner container of a double-walled container system to the interstitial space of the medical device, such that said inner container is in fluid communication with the interstitial space; expanding the flexible inner container in response to a pressure decrease in the decontamination chamber; and collapsing the flexible inner container in response to a pressure increase in the decontamination chamber.

[0021] In accordance with yet another aspect of the present invention, there is provided an apparatus for controlling the pressure differential between a decontamination chamber and an interstitial space of a medical device located in the decontamination chamber, during a vacuum assisted gas / vapor decontamination process: a reversible fluid pump operable in forward and rearward directions, said reversible fluid pump controlled by a control unit that receives data indicative of a pressure level in the decontamination chamber; a fluid line having a first end with a connector assembly adapted to fit onto a device port of the medical device to put the fluid line in fluid communication with an interstitial space of the medical device, and asecond end connected with the reversible fluid pump, said reversible pump in fluid communication with an external environment outside of the decontamination chamber.

[0022] In accordance with yet another aspect of the present invention, there is provided an apparatus for controlling the pressure differential between a decontamination chamber and an interstitial space of a medical device located in the decontamination chamber, during a vacuum assisted gas / vapor decontamination process: a double-walled container system including: (a) a rigid outer container defining an interior space, and (b) a flexible inner container located within the interior space of the outer container, said inner container defining an interior space of varying volume; and a fluid line having a first end with a connector assembly adapted to fit onto a device port of the medical device to put the fluid line in fluid communication with an interstitial space of the medical device, and a second end connected with the inner container to put the fluid line in fluid communication with the interior space of the inner container.

[0023] An advantage of the present invention is the provision of a decontamination system that reduces the differential pressure between an interstitial space of a medical device (such as an endoscope) and a decontamination chamber, during a sub-atmospheric decontamination process.

[0024] Another advantage of the present invention is the provision of a decontamination system that prevents damage to a medical device due to over-pressurization of an interstitial space of the medical device, during a sub-atmospheric decontamination process.

[0025] Another advantage of the present invention is the provision of a decontamination system that prevents damage to a medical device by preventing the ingress of decontaminant gas / vapor into the interstitial space of the medical device, during a sub- atmospheric decontamination process.

[0026] A still another advantage of the present invention is the provision of a method for decontamination that reduces the differential pressure between an interstitial space of a medical device (such as an endoscope) and a decontamination chamber, during a sub- atmospheric decontamination process.

[0027] A still another advantage of the present invention is the provision of a method for decontamination that prevents damage to a medical device due to over-pressurization of an interstitial space of the medical device, during a sub-atmospheric decontamination process.

[0028] A still further advantage of the present invention is the provision of a method for decontamination that prevents damage to a medical devices by preventing the ingress of decontaminant gas / vapor into the interstitial space of the medical device, during a sub- atmospheric decontamination process.

[0029] These and other advantages will become apparent from the following description of illustrated embodiments taken together with the accompanying drawings and the appended claims.Brief Description of the Drawings

[0030] The invention may take physical form in certain parts and arrangement of parts, embodiments of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein:

[0031] FIG. 1 is a schematic block diagram of a decontamination system according to a first embodiment of the present invention;

[0032] FIG. 2 is a schematic block diagram of a decontamination system according to a second embodiment of the present invention;

[0033] FIGS. 3-6 are schematic block diagrams of the second embodiment, illustrating operation of the present invention during an example sterilization cycle.Detailed Description of the Invention

[0034] Referring now to the drawings wherein the showings are for the purposes of illustrating embodiments of the invention only and not for the purposes of limiting same, FIG.1 shows a decontamination system 10 according to a first embodiment. Decontamination system 10 is generally comprised of a chamber housing 20 defining a decontamination or sterilization chamber 22, a control unit 50, a sensing element 52, a vacuum pump 60, and a reactive agent source 70. Decontamination system also includes a temperature sensor (not shown) for sensing the temperature in sterilization chamber 22 and providing data indicative of temperature to control unit 50.

[0035] Chamber 22 is dimensioned to receive medical devices (or other articles) that are to be sterilized. In the illustrated embodiment, the medical devices are endoscopes. Sterilization chamber 22 includes a first chamber port 24 and a second chamber port 26 that provide access to sterilization chamber 22, and a venting valve 28 for increasing the pressure within chamber 22, as will be explained below. Venting valve 28 is electrically connected with control unit 50, and is movable between open and closed positions by control unit 50.

[0036] Control unit 50 takes the form of a conventional programmable computing device, such as a microcomputer or microcontroller, including memory for storage of programmed control algorithms.

[0037] Sensing element 52 is located inside chamber 22 and takes the form of a pressure sensor (e.g., a MEM-based pressure sensor). Sensing element 52 is electrically connected to control unit 50 to provide data indicative of the pressure inside chamber 22.

[0038] Vacuum pump 60 is a conventional vacuum pump for reducing the pressure inside chamber 22. Vacuum pump 60 is in fluid communication with chamber 22 and electrically connected with control unit 50, which is programmed to activate and deactivate vacuum pump 60 according to a control algorithm.

[0039] Reactive agent source 70 is a source of a gaseous / vaporous chemical sterilant (e.g., hydrogen peroxide, peracetic acid, ozone, chlorine dioxide, nitrogen dioxide, and the like) which is supplied to chamber 22. Reactive agent source 70 is in fluid communication with chamber 22 and is electrically connected with control unit 50, which is programmed to activate and deactivate reactive agent source 70 in accordance with a control algorithm. When reactive agent source 70 is activated, a gaseous / vaporous chemical sterilant is injected into chamber 22.

[0040] In the illustrated embodiment of the present invention, a tray 200, containing a medical device 100 that is to be sterilized, is placed inside chamber 22 for sterilization. Medical device 100 takes the form of a conventional endoscope in the illustrated embodiment of the present invention. Medical device 100 includes a device port 102 for access to an interstitial space within medical device 100. In the illustrated embodiment, device port 102 is a venting connector valve of an endoscope.

[0041] In accordance with the first embodiment of the present invention, decontamination system 10 also includes a pump 120, which is a conventional reversible fluidpump (e.g., a reversible peristaltic pump suitable for pumping gases), and a fluid line 130 (e.g., a tubing interface). A first end of fluid line 130 has a connector assembly adapted to fit onto device port 102 (i.e., venting connector valve) of device 100. A second end of fluid line 130 is connected with pump 120. Accordingly, pump 120 is in fluid communication with the interstitial space of the endoscope via fluid line 130, which connects pump 120 to device port 102 via second chamber port 26. Pump 120 is also in fluid communication with an external environment that is outside of chamber 22.

[0042] The function of pump 120 is to transfer air / gas between the interstitial space of device 100 and the external environment outside of chamber 22 by operating pump 120 in a forward direction to move air / gas from the interstitial space of device 100 to the external environment, and in a reverse direction to move air from the external environment into the interstitial space of device 100. According to one embodiment of the present invention, the external environment is the environment outside of decontamination system 10 (e.g., the environmental air surrounding decontamination system 10). In accordance with an alternative embodiment, the external environment is the interior space of a tank or vessel 220 that is a component of decontamination system 10 located outside of chamber 22. For example, vessel 220 could take the form of a rigid compartment located outside of chamber 22 that is in fluid connection with pump 120, as illustrated with dashed lines in FIG. 1. Vessel 220 is fluidly connected to pump 120 so that air / gas is removed or injected into vessel 220 prior to or during a dynamic pressure change occurring in the interstitial space of device 100 and chamber 22 during operation of decontamination system 10. Consequently, the operation of pump 120 reduces the differential pressure between the interstitial space of device 100 and the pressure inside chamber 22, as will be explained in detail below. Pump 120 is electrically connected with control unit 50, which is programmed to operate pump 120 in accordance with a control algorithm for reducing the differential pressure. Control unit 50 uses data received from sensing element 122, which is indicative of the pressure level within chamber 22, to activate / deactivate pump 120 in the forward / reverse directions.

[0043] Operation of the present invention according to the first embodiment will now be described. The connector assembly of fluid line 130 is connected with device port 102 (venting connector valve) of device 100. As indicated above, pump 120 is operable by control unit 50 to evacuate gas / air from the interstitial space of device 100 to an external environmentvia fluid line 130, and to inject air into the interstitial space of device 100 from the external environment via fluid line 130. The operating mode of pump 120 is determined in accordance with the pressure level detected by sensing element 52 and reported to control unit 50.

[0044] A user initiates a reprocessing operation via control unit 50. Control unit 50 then commences operating cycles for decontamination system 10 according to a programmed control algorithm. Pressure changes occur inside chamber 22 during various operating phases of the operating cycles. During an operating phase of decontaminating system 10 where the pressure in chamber 22 is reduced (vacuum pulldown), sensing element 52 detects the decreasing pressure (depressurization), and in response, control unit 50 activates pump 120 in the forward direction to evacuate air / gas from the interstitial space of device 100 into the external environment. As a result, the pressure inside the interstitial space of device 100 is reduced, which in turn, reduces the differential pressure between the interstitial space of device 100 and chamber 22.

[0045] During a subsequent operating phase where the pressure in the chamber 22 is increased (re-pressurization), sensing element 52 detects the pressure increase, and in response, control unit 50 activates pump 120 in the reverse direction to inject air into the interstitial space of device 100 from the external environment. As a result, pressure inside the interstitial space of device 100 is increased, which in turn, reduces the differential pressure between the interstitial space of device 100 and chamber 22. Air is injected by pump 120 into the interstitial space of device 100 until the pressure in the interstitial space is substantially equal to the pressure in chamber 22.

[0046] By the selective activation of pump 120, the present invention effectively reduces the differential pressure between an interstitial space of device 100 and decontamination chamber 22.

[0047] It should be appreciated that pump 120 may take the form of a single reversible pump, two non-reversible pumps, a non-reversible pump and a valve, or another method for adding and removing volume from the interstitial space of device 100.

[0048] It is further contemplated that the embodiment of the present invention shown in FIG. 1 may operate according to an alternative operating procedure. According to the alternative operating procedure, the control algorithm of control unit 50 determines the volume of air that can be held in the interstitial space of device 100, based on parameters of device 100(such as, model, dimensions, and the like). The parameters may be input into control unit 50 manually via an input device (e.g., a keypad or touchscreen), via a scanned RFID tag, or the like. Control unit 50 activates pump 120 to (a) inject air / gas from vessel 220 into the interstitial space of device 100 and (b) remove air / gas from interstitial space of device 100 and return the air / gas back into vessel 220. Fluid line 130 fluidly connects vessel 220 (via pump 120) to device port 102 of device 100. Where device 100 is an endoscope, device port 102 may take the form of the endoscope leak port.

[0049] Referring now to FIG. 2, a decontamination system 12 according to a second embodiment of the present invention will be described. Decontamination system 12 is generally comprised of chamber housing 20 defining sterilization chamber 22, control unit 50, sensing element 52, vacuum pump 60, reactive agent source 70, and a temperature sensor (not shown), all of which are described above with respect to the first embodiment.

[0050] In accordance with the second embodiment of the present invention, decontamination system 12 also includes a double-walled container system 140, which is a passive component that replaces pump 120 of the first embodiment. This passive component serves as a “ballast” for air / gas from the interstitial space of device 100, as will be explained below. Double-walled container system 140 is generally comprised of a rigid outer container 150 defining an interior space 155, and a flexible inner container 160 located within interior space 155 of outer container 150. Flexible inner container 160 defines an interior space 165 of varying volume. Flexible inner container 160 expands and collapses, thereby varying the volume of interior space 165. Double-walled container system 140 is located external to chamber 22. In an alternative embodiment, flexible inner container 160 is replaced with a flexible diaphragm that is attachable to one or more walls of rigid outer container 150.

[0051] As indicated above, the first end of fluid line 130 has a connector assembly adapted to fit onto device port 102 (venting connector valve) of device 100. In the second embodiment of the present invention, the second end of fluid line 130 is connected with flexible inner container 160 such that it is in fluid communication with interior space 165. Accordingly, fluid line 130 puts interior space 165 of flexible inner container 160 in fluid communication with the interstitial space of device 100.

[0052] In operation, flexible inner container 160 begins in a collapsed state (i.e., interior space 165 at minimum volume) when chamber 22 is at atmospheric pressure. Flexibleinner container 160 expands (i.e., volume of interior space 165 increases) when the pressure in chamber 22 decreases. Flexible inner container collapses (i.e., volume of interior space 165 decreases) when chamber 22 returns to atmospheric pressure. As flexible inner container 160 moves between a collapsed state and an expanded state, it functions to reduce the pressure differential between the interstitial space of device 100 and chamber 22, as will be further explained below.

[0053] Operation of the present invention according to the second embodiment will now be illustrated with reference to FIGS. 3-6. These figures illustrate operation of decontamination system 12, during an example sterilization cycle, to sterilize a medical device 100 taking the form of an endoscope. The example sterilization cycle is representative of sterilization cycles of many typical sub-atmospheric decontamination systems.

[0054] It will be appreciated that the present invention utilizes the principles under the Ideal Gas Laws. In accordance with the Ideal Gas Law (PV = nRT, where nRT arc constant in the present case):• as pressure decreases in the interstitial space of the endoscope, the volume V of interior space 165 increases due to expansion of flexible inner container 160;• when interior space 165 has increased to its maximum volume, the volume V of interior space 165 remains unchanged, and thus, the pressure in the interstitial space of the endoscope remains unchanged; and• as pressure increases in the interstitial space of the endoscope, the volume V of interior space 165 decreases due to collapse / contraction of flexible inner container 160.

[0055] FIG. 3 illustrates the conditions at the commencement of the example sterilization cycle (time t = 0). Chamber 22 is at atmospheric pressure (760 torr), the interstitial space of the endoscope is at atmospheric pressure (760 torr), and flexible inner container 160 is in a collapsed state (760 torr). At this stage, the pressure differential between the interstitial space of the endoscope and chamber 22 is 0 torr.

[0056] FIG. 4 illustrates the conditions partially through a vacuum pull down in chamber 22. The pressure in chamber 22 continuously decreases from 760 torr to 150 torr. The pressure in the interstitial space of the endoscope decreases from 760 torr to 150 torr, as volume V of interior space 165 increases. The pressure in flexible inner container 160decreases from 760 torr to 150 torr. At this stage, the pressure differential between the interstitial space of the endoscope and chamber 22 is 0 torr.

[0057] FIG. 5 illustrates the conditions at the end of the vacuum pulldown. The pressure in chamber 22 is at a minimum (1 torr). The pressure in the interstitial space of the endoscope and the pressure in flexible inner container 160 do not decrease further after interior space 165 has reached a maximum volume V. The interstitial space of the endoscope is kept at positive pressure in comparison to the pressure in chamber 22. This helps prevent ingress of decontaminant / sterilant chemistry into the interstitial space of the endoscope. At this stage, the pressure differential between the interstitial space of the endoscope and chamber 22 is 149 torr. It should be appreciated that while this example has a minimum pressure of 1 torr in the sterilization chamber, the minimum pressure in the sterilization chamber can vary between decontamination systems and sterilization cycles. The present invention can be used to pull the sterilization chamber down to any desired vacuum level. It should be further appreciated that the maximum volume V of interior space 160 of flexible inner container can be selected to allow a lower pressure in the interstitial space of the endoscope. As a result, the pressure differential between the interstitial space of the endoscope and chamber 22 can be a smaller value than in the illustrated example.

[0058] FIG. 6 illustrates the conditions at the end of a vacuum break. The pressure increases in chamber 22 as it returns to atmospheric pressure (760 torr). The volume V of interior space 165 decreases to the minimum volume as flexible inner container 160 returns to the collapsed state. The pressure in the interstitial space of the endoscope increases until it returns to atmospheric pressure (760 torr). At this stage, the pressure differential between the interstitial space of the endoscope and chamber 22 is 0 torr.

[0059] It should be appreciated that the minimum pressure in the interstitial space in the forgoing example is 150 torr, but this minimum pressure may vary depending on the minimum vacuum pulled in the sterilization chamber and the rated interstitial pressure of the endoscope.

[0060] As an additional element for the first and second embodiments, it is contemplated that a chemical indicator (CI) may be placed in fluid line 130 to provide proof that no decontamination chemistry has entered the interstitial space of medical device 100.Failure of the chemical indicator to change assures that the integrity of the interstitial space has been maintained.

[0061] The foregoing describes specific embodiments of the present invention. It should be appreciated that these embodiments are described for purposes of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

Claims

What is claimed is:

1. A vacuum assisted gas / vapor decontamination system comprising: a decontamination chamber dimensioned to receive a medical device for sterilization, said decontamination chamber having a venting valve for increasing the pressure in the decontamination chamber; a vacuum pump for reducing pressure in the decontamination chamber; a sensing element for sensing a pressure level in the decontamination chamber; a reactive agent source for injecting a gaseous / vaporous chemical sterilant into the decontamination chamber; a reversible fluid pump operable in forward and rearward directions; a fluid line having a first end with a connector assembly adapted to fit onto a device port of the medical device to put the fluid line in fluid communication with an interstitial space of the medical device, and a second end connected with the reversible fluid pump, said reversible pump in fluid communication with an external environment outside of the decontamination chamber; and a control unit for controlling operation of the decontamination system, said control unit operable to activate the reversible fluid pump to operate in the forward direction to transfer air / gas from the interstitial space to the external environment and operable to activate the reversible fluid pump to operate in the reverse direction to inject air into the interstitial space from the external environment, wherein said control unit activates the fluid pump in the forward and reverse directions in accordance with the pressure level detected by the sensing element.

2. The vacuum assisted gas / vapor decontamination system according to claim 1, wherein the control unit activates the reversible pump in the forward direction to decrease pressure inside the interstitial space.

3. The vacuum assisted gas / vapor decontamination system according to claim 1, wherein the control unit activates the reversible pump in the reverse direction to increase pressure inside the interstitial space.

4. The vacuum assisted gas / vapor decontamination system according to claim 1, wherein the control unit activates the reversible fluid pump to operate in the forward direction to transfer air / gas from the interstitial space into the external environment in response to the sensing element detecting a decreasing pressure level in the decontamination chamber.

5. The vacuum assisted gas / vapor decontamination system according to claim 1, wherein the control unit activates the reversible fluid pump to operate in the reverse direction to inject air into the interstitial space from the external environment in response to sensing element detecting an increasing pressure level in the decontamination chamber.

6. The vacuum assisted gas / vapor decontamination system according to claim 1, wherein the device port is a venting connector valve.

7. The vacuum assisted gas / vapor decontamination system according to claim 1, wherein the medical device is an endoscope.

8. A vacuum assisted gas / vapor decontamination system comprising: a decontamination chamber dimensioned to receive a medical device for sterilization, said decontamination chamber having a venting valve for increasing the pressure in the decontamination chamber; a vacuum pump for reducing pressure in the decontamination chamber; a sensing element for sensing a pressure level in the decontamination chamber; a reactive agent source for injecting a gaseous / vaporous chemical sterilant into the decontamination chamber; a double-walled container system including: a rigid outer container defining an interior space, anda flexible inner container located within the interior space of the outer container, said inner container defining an interior space of varying volume; a fluid line having a first end with a connector assembly adapted to fit onto a device port of the medical device to put the fluid line in fluid communication with an interstitial space of the medical device, and a second end connected with the inner container to put the fluid line in fluid communication with the interior space of the inner container; and a control unit for controlling operation of the decontamination system.

9. The vacuum assisted gas / vapor decontamination system according to claim 8, wherein the flexible inner container moves between a collapsed state and an expanded state to reduce a pressure differential between the interstitial space of the medical device and the decontamination chamber.

10. The vacuum assisted gas / vapor decontamination system according to claim 8, wherein the volume of the interior space of the inner container increases in response to a decrease of pressure in the decontamination chamber, and the volume of the interior space of the inner container decreases in response to an increase of pressure in the decontamination chamber.

11. The vacuum assisted gas / vapor decontamination system according to claim 8, wherein the device port is a venting connector valve.

12. The vacuum assisted gas / vapor decontamination system according to claim 8, wherein the medical device is an endoscope.

13. A method for controlling the pressure differential between a decontamination chamber and an interstitial space of a medical device located in the decontamination chamber, during a vacuum assisted gas / vapor decontamination process, said method comprising: activating a reversible pump in a forward direction to evacuate air / gas from the interstitial space of the medical device into an external environment outside of thedecontamination chamber, when detecting decreasing pressure in the decontamination chamber; and activating the reversible pump in a reverse direction to inject air into the interstitial space of the medical device from the external environment when detecting an increasing pressure in the decontamination chamber.

14. The method according to claim 13, wherein the method further comprises: activating the reversible pump in response to pressure levels detected by a pressure sensing element located in the decontamination chamber.

15. The method according to claim 13, wherein the medical device is an endoscope.

16. A method for controlling the pressure differential between a decontamination chamber and an interstitial space of a medical device located in the decontamination chamber, during a vacuum assisted gas / vapor decontamination process, said method comprising: connecting a flexible inner container of a double-walled container system to the interstitial space of the medical device, such that said inner container is in fluid communication with the interstitial space; expanding the flexible inner container in response to a pressure decrease in the decontamination chamber; and collapsing the flexible inner container in response to a pressure increase in the decontamination chamber.

17. The method according to claim 16, wherein the double-walled container system operates as a passive component.

18. The method according to claim 16, wherein the medical device is an endoscope.

19. An apparatus for controlling the pressure differential between a decontamination chamber and an interstitial space of a medical device located in the decontamination chamber, during a vacuum assisted gas / vapor decontamination process:a reversible fluid pump operable in forward and rearward directions, said reversible fluid pump controlled by a control unit that receives data indicative of a pressure level in the decontamination chamber; a fluid line having a first end with a connector assembly adapted to fit onto a device port of the medical device to put the fluid line in fluid communication with an interstitial space of the medical device, and a second end connected with the reversible fluid pump, said reversible pump in fluid communication with an external environment outside of the decontamination chamber.

20. An apparatus for controlling the pressure differential between a decontamination chamber and an interstitial space of a medical device located in the decontamination chamber, during a vacuum assisted gas / vapor decontamination process: a double-walled container system including: a rigid outer container defining an interior space, and a flexible inner container located within the interior space of the outer container, said inner container defining an interior space of varying volume; and a fluid line having a first end with a connector assembly adapted to fit onto a device port of the medical device to put the fluid line in fluid communication with an interstitial space of the medical device, and a second end connected with the inner container to put the fluid line in fluid communication with the interior space of the inner container.

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