Patent Description:
Before sterilization, medical devices may be packaged within containers or pouches having a semi-permeable barrier that allows transmission of the sterilizing fluid-sometimes referred to as a sterilant-but prevents admission of contaminating organisms, particularly post-sterilization and until the package is opened by medical personnel. For the sterilization cycle to be efficacious, the contaminating organisms within the package must be killed because any organisms that survive the sterilization cycle could multiply and re-contaminate the medical device. Diffusion of the sterilant may be particularly problematic for medical devices that have diffusion-restricted spaces therein because these diffusion-restricted spaces may reduce the likelihood that a sterilization cycle may be effective. For example, some endoscopes have one or more long narrow lumens into which the sterilant must diffuse in sufficient concentration for sufficient time to achieve a successful sterilization cycle.

Sterilization of medical devices may be performed with an automated sterilization system such as a STERRAD® System by Advanced Sterilization Products of Irvine, California. Examples of automated sterilization systems are described in <CIT>; <CIT>; <CIT> ; <CIT> ; and <CIT>.

Some sterilization systems may use vaporized chemical sterilants or chemical gas such as hydrogen peroxide, peracetic acid, ozone, chlorine dioxide, nitrogen dioxide, etc., to sterilize medical devices. Examples of such systems are described in <CIT>, <CIT>, in <CIT> which discloses sterilization by low-vapor-pressure, in <CIT> which discloses sterilization by hydrogen peroxide and ozone, and <CIT> which discloses sterilization by a hydrogen peroxide gas plasma. Some such systems provide a hydrogen peroxide/gas plasma sterilization system comprising a vacuum chamber and plasma source and increased concentration of hydrogen peroxide for sterilization. Some such systems may have difficulty sterilizing lumens of some medical devices if their length exceeds a certain value; or the processing time of such systems may still not be fast enough for some applications. Thus, some medical devices such as long and/or narrow flexible endoscopes may not be completely sterilized by these systems due to the insufficient reach of sterilant vapor to the inside of the channels. Such medical devices might therefore only be disinfected without being sterilized. Sterilization systems that use ethylene oxide may have a relatively long processing time (e.g., longer than <NUM> hours), which may be undesirable in some cases.

Operator error may result in medical devices that are erroneously believed to be decontaminated being returned to service. Confirming that a sterilization cycle has been efficacious may help medical personnel avoid using a contaminated medical device on a patient. The sterilized medical device might not itself be checked for contaminating organisms because such an activity may introduce other contaminating organisms to the medical device, thereby re-contaminating it. Thus, an indirect check may be performed using a sterilization indicator. A sterilization indicator is a device that may be placed alongside or in proximity to a medical device being subject to a sterilization cycle, such that the sterilization indicator is subject to the same sterilization cycle as the medical device. For instance, a biological indictor having a predetermined quantity of microorganisms may be placed into a sterilization chamber alongside a medical device and subject to a sterilization cycle. After the cycle is complete, the microorganisms in the biological indicator may be cultured to determine whether any of the microorganisms survived the cycle. The presence or absence of living microorganisms in the biological indicator will indicate whether the sterilization cycle was effective.

While a variety of systems and methods have been made and used for surgical instrument sterilization, it is believed that no one prior to the inventor(s) has made or used the technology as described herein.

It is believed the present invention will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which:.

As will be realized, the technology described herein is capable of other different and obvious aspects, all without departing from the scope of the appended claims.

<FIG> depicts an exemplary sterilizing cabinet (<NUM>) that is operable to sterilize medical devices such as endoscopes, etc. Sterilizing cabinet (<NUM>) of the present example includes a sterilization chamber (<NUM>), which is configured to receive one or more medical devices for sterilization. While not shown, sterilizing cabinet (<NUM>) also includes a door that opens and closes sterilization chamber (<NUM>) in response to actuation of a kick plate. An operator may thereby open and close sterilization chamber (<NUM>) in a hands-free fashion. Of course, any other suitable features may be used to provide selective access to sterilization chamber. Sterilizing cabinet (<NUM>) also includes a sterilization module (<NUM>) that is operable to dispense a sterilant into sterilization chamber (<NUM>) in order to sterilize medical devices contained in sterilization chamber (<NUM>). In the present example, sterilization module (<NUM>) is configured to receive replaceable sterilant cartridges (<NUM>) containing a certain amount of sterilant. By way of example only, each sterilant cartridge (<NUM>) may contain enough sterilant to perform five sterilization procedures.

Sterilizing cabinet (<NUM>) of the present example further includes a touch screen display (<NUM>). Touch screen display (<NUM>) is operable to render the various user interface display screens, such as those described in <CIT>. Of course, touch screen display (<NUM>) may display various other screens as well. Touch screen display (<NUM>) is further configured to receive user input in the form of the user contacting touch screen display (<NUM>) in accordance with conventional touch screen technology. In addition, or in the alternative, sterilizing cabinet (<NUM>) may include various other kinds of user input features, including but not limited to buttons, keypads, keyboards, a mouse, a trackball, etc..

Sterilizing cabinet (<NUM>) of the present example further includes a processor (<NUM>), which is in communication with sterilization module (<NUM>) and with touch screen display (<NUM>). Processor (<NUM>) is operable to execute control algorithms to drive sterilization module (<NUM>) in accordance with user input. Processor (<NUM>) is further operable to execute instructions to display the various screens on touch screen display (<NUM>); and to process instructions received from a user via touch screen display (<NUM>) (and/or via other user input features). Processor (<NUM>) is also in communication with various other components of sterilization cabinet (<NUM>) and is thereby operable to drive those components and/or process input and/or other data from those components. Various suitable components and configurations that may be used to form processor (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein.

Sterilizing cabinet (<NUM>) of the present example further includes an identification tag reader (<NUM>), which is operable to read an identification tag of a biological indicator as described herein. By way of example only, identification tag reader (<NUM>) may comprise an optical reader that is operable to read an optical identification tag (e.g., barcode, QR code, etc.) of a biological indicator. In addition, or in the alternative, identification tag reader (<NUM>) may comprise RFID reader that is operable to read an RFID identification tag (e.g., barcode, QR code, etc.) of a biological indicator. Various suitable components and configurations that may be used to form identification tag reader (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein. Data received through identification tag reader (<NUM>) is processed through processor (<NUM>).

Sterilizing cabinet (<NUM>) of the present example further includes a memory (<NUM>), which is operable to store control logic and instructions and that are executed by processor (<NUM>) to drive components such as sterilization module (<NUM>), touch screen display (<NUM>), communication module (<NUM>), and identification tag reader (<NUM>). Memory (<NUM>) may also be used to store results associated with setup of a sterilization cycle, performance of a load conditioning cycle, performance of a sterilization cycle, and/or various other kinds of information. Various suitable forms that memory (<NUM>) may take, as well as various ways in which memory (<NUM>) may be used, will be apparent to those of ordinary skill in the art in view of the teachings herein.

Sterilizing cabinet (<NUM>) of the present example further includes a printer (<NUM>), which is operable to print information such as results associated with setup of a sterilization cycle, performance of a load conditioning cycle, performance of a sterilization cycle, and/or various other kinds of information. By way of example only, printer (<NUM>) may comprise a thermal printer, though of course any other suitable kind of printer may be used. Various suitable forms that printer (<NUM>) may take, as well as various ways in which printer (<NUM>) may be used, will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that printer (<NUM>) is merely optional and may be omitted in some versions.

Sterilizing cabinet (<NUM>) of the present example further includes a vacuum source (<NUM>) and a venting valve (<NUM>). Vacuum source (<NUM>) is in fluid communication with sterilization chamber (<NUM>) and is also in communication with processor (<NUM>). Thus, processor (<NUM>) is operable to selectively activate vacuum source (<NUM>) in accordance with one or more control algorithms. When vacuum source (<NUM>) is activated, vacuum source (<NUM>) is operable to reduce the pressure within sterilization chamber (<NUM>) as will be described in greater detail below. Venting valve (<NUM>) is also in fluid communication with sterilization chamber (<NUM>). In addition, venting valve (<NUM>) is in communication with processor (<NUM>) such that processor (<NUM>) is operable to selectively activate venting valve (<NUM>) in accordance with one or more control algorithms. When venting valve (<NUM>) is activated, venting valve (<NUM>) is operable to vent sterilization chamber (<NUM>) to atmosphere as will be described in greater detail below. Various suitable components that may be used to provide vacuum source (<NUM>) and venting valve (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein.

In addition to the foregoing, sterilizing cabinet (<NUM>) may be configured and operable in accordance with at least some of the teachings of <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and/or <CIT>.

<FIG> depicts a high level flowchart of an exemplary set of steps that sterilizing cabinet (<NUM>) could perform to sterilize a used medical device, such as an endoscope. Sterilizing cabinet (<NUM>) may be configured to perform one or more sterilization cycles, with different sterilization cycles being appropriate for different types and quantities of medical devices. Thus, as an initial step, sterilizing cabinet (<NUM>) may display one or more available sterilization cycles via touch screen display (<NUM>) and then receive a sterilization cycle selection (block <NUM>) from the user.

Sterilizing cabinet (<NUM>) may also display instructions indicating whether a biological indicator should be used with the selected sterilization cycle, and receive a biological indicator identification (block <NUM>). Such a biological indicator identification (block <NUM>) may be provided via identification tag reader (<NUM>), via touch screen display (<NUM>), or otherwise. A biological indicator may be placed inside sterilization chamber (<NUM>) of sterilizing cabinet (<NUM>) before the sterilization cycle begins and may remain in the sterilization chamber during the sterilization cycle. The user may thus identify the particular biological indicator (block <NUM>) before the biological indicator is placed in the sterilization chamber. The biological indicator may contain microorganisms that are responsive to a particular sterilization cycle. Upon completion of the sterilization cycle, the biological indicator may be tested for the microorganisms in order to provide a measure of the effectiveness of the sterilization cycle. A biological indicator may not necessarily be required for all sterilization cycles, but may be required based on hospital rules or local regulations.

Selection of a sterilization cycle (block <NUM>) and identification of a biological indicator (block <NUM>) may define one or more requirements for the configuration and arrangement of medical devices within sterilization chamber (<NUM>). Thus, in order to provide preparation for the sterilization cycle (<NUM>) once the sterilization cycle has been selected (block <NUM>) and the biological indicator has been identified (block <NUM>), sterilizing cabinet (<NUM>) may provide a display via touch screen display (<NUM>) indicating a proper medical device placement. This display may serve as a visual guide to a user's placement of medical device(s) (and perhaps a biological indicator) within sterilizing chamber (<NUM>) of sterilizing cabinet (<NUM>), based on the sterilization cycle selection (block <NUM>). A door of sterilization chamber (<NUM>) may be opened to enable the user to place the medical device(s) (and perhaps a biological indicator) within sterilizing chamber (<NUM>) as instructed.

Once the user has placed the medical device in sterilizing chamber (<NUM>) based on these instructions, the user may press a start button or other button indicating that medical device placement is complete. In some versions, sterilizing cabinet (<NUM>) is configured to automatically verify proper medical device placement. By way of example only, sterilizing cabinet (<NUM>) may employ photo sensors, imaging devices, weight sensors, and/or other components to verify proper medical device placement in sterilizing chamber (<NUM>). It should be understood, however, that some versions of sterilizing cabinet (<NUM>) may lack the capability of automatically verifying proper placement of a medical device within sterilizing chamber (<NUM>).

If medical device placement is verified and/or the user has otherwise completed the cycle preparation (block <NUM>), sterilizing cabinet (<NUM>) may start a load conditioning process (block <NUM>). The load conditioning process (block <NUM>) prepares sterilization chamber (<NUM>) and the medical device(s) within sterilization chamber (<NUM>) for optimal sterilization during a sterilization cycle. Conditioning may include controlling and optimizing one or more characteristics of sterilization chamber (<NUM>). For example, during load conditioning, sterilizing cabinet (<NUM>) may continuously monitor the level of moisture within sterilization chamber (<NUM>) while reducing the level of moisture by, for example, circulating and dehumidifying the air of sterilization chamber (<NUM>), creating a vacuum within sterilization chamber (<NUM>), heating sterilization chamber (<NUM>), and/or other methods for dehumidifying a sealed chamber. This may continue until sterilizing cabinet (<NUM>) determines that an acceptable level of moisture has been reached.

As part of the load conditioning cycle (block <NUM>), sterilizing cabinet (<NUM>) may also continuously detect the temperature within sterilization chamber (<NUM>) while heating sterilization chamber (<NUM>) by, for example, convection of heated air, conduction through an interior surface of sterilization chamber (<NUM>), and/or using other techniques. This may continue until sterilizing cabinet (<NUM>) determines that an acceptable internal temperature has been reached. Various conditioning actions such as controlling temperature or humidity may be performed in parallel or in sequence. It should also be understood that the load conditioning cycle (block <NUM>) may verify that the sterilization chamber is sealed; verifying contents of the sterilization chamber; checking physical characteristics of the contents of the sterilization chamber such as content volume, content weight, or other characteristics; and/or performing one or more conditioning steps that may include chemical treatment, plasma treatment, or other types of treatment to reduce moisture, raise temperature, and/or otherwise prepare the medical devices in sterilization chamber (<NUM>) for the sterilization cycle (block <NUM>).

While the one or more conditioning actions are being performed as part of the load conditioning cycle (block <NUM>), sterilizing cabinet (<NUM>) may display information via touch screen display (<NUM>) indicating to a user the duration of time before the sterilization cycle (block <NUM>) performance may begin. Once all load conditioning criteria have been successfully met, the load conditioning cycle (block <NUM>) is complete, and the sterilization cycle (block <NUM>) may then be performed. It should therefore be understood that sterilizing cabinet (<NUM>) is configured such that the sterilization cycle (block <NUM>) is not actually initiated until after the load conditioning cycle (block <NUM>) is complete. It should also be understood that the load conditioning cycle (block <NUM>) may be omitted or varied in some versions of sterilizing cabinet (<NUM>) operation.

As noted above, sterilization cabinet (<NUM>) may begin performing the sterilization cycle (block <NUM>) automatically and immediately after load conditioning (block <NUM>) has been completed. The sterilization cycle (block <NUM>) may include exposing the medical device(s) in the sterilizing chamber to pressurized sterilant gas, further heat treatment, chemical treatment, plasma treatment, vacuum treatment, and/or other types of sterilization procedures. During performance of the sterilization cycle (block <NUM>), sterilization cabinet (<NUM>) may display information via touch screen display (<NUM>) such as a duration remaining for the sterilization cycle (block <NUM>), the current stage of the sterilization cycle (block <NUM>) (e.g. plasma, vacuum, injection, heat, chemical treatment), and/or other information.

In some versions, the sterilization cycle (block <NUM>) includes the exemplary sub-steps shown in <FIG>. In particular, the cycle may begin with a vacuum being applied (block <NUM>) within sterilization chamber (<NUM>). In order to provide such a vacuum, processor (<NUM>) may activate vacuum source (<NUM>) in accordance with a control algorithm. Processor (<NUM>) will then determine (block <NUM>) whether a sufficient pressure level has been reached within sterilization chamber (<NUM>). By way of example only, processor (<NUM>) may monitor data from one or more pressure sensors within sterilization chamber (<NUM>) as part of the determination step (block <NUM>). Alternatively, processor (<NUM>) may simply activate vacuum source (<NUM>) for a predetermined time period and assume that the appropriate pressure has been reached in sterilization (<NUM>) based upon the duration for which vacuum source (<NUM>) is activated. Other suitable ways in which processor (<NUM>) may determine (block <NUM>) whether a sufficient pressure level has been reached within sterilization chamber (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein. Until the appropriate pressure level has been reached within sterilization chamber (<NUM>), vacuum source (<NUM>) will remain activated.

Once sterilization chamber (<NUM>) reaches an appropriate pressure level (e.g., between approximately <NUM> Pa (<NUM> torr) and approximately <NUM> (<NUM> torr)), processor (<NUM>) then activates sterilization module (<NUM>) to apply a sterilant (block <NUM>) in sterilization chamber (<NUM>). This stage of the process may be referred to as the "transfer phase. " By way of example only, the sterilant may comprise a vapor of oxidizing agent such as hydrogen peroxide, peroxy acids (e.g. peracetic acid, performic acid, etc.), ozone, or a mixture thereof. Furthermore, the sterilant may comprise chlorine dioxide. Various other suitable forms that the sterilant may take are described herein; while other forms will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that, in some versions, the sterilant may be applied (block <NUM>) in different ways based on the user's selection of cycle (block <NUM>) as described above. Once the sterilant has been applied (block <NUM>) to sterilization chamber (<NUM>), processor (<NUM>) monitors the time (block <NUM>) to determine whether a sufficient, predetermined duration has passed. By way of example only, this predetermined duration may be anywhere from a few seconds to several minutes. Until the predetermined duration has passed, sterilization chamber (<NUM>) remains in a sealed state at the above-noted predetermined pressure level, with the applied sterilant acting upon the medical device(s) contained within sterilization chamber (<NUM>).

After the predetermined duration has passed, processor (<NUM>) activates (block <NUM>) venting valve (<NUM>) to vent sterilization chamber (<NUM>) to atmosphere. In some versions, sterilization chamber (<NUM>) is allowed to reach atmospheric pressure, while in other versions sterilization chamber (<NUM>) only reaches sub-atmospheric pressure. The venting stage of the process may be referred to as the "diffusion phase. " In the present example, the sterilization cycle is then complete (block <NUM>) after completion of the diffusion phase. In some other instances, vacuum is again applied to sterilization chamber (<NUM>) after completion of the diffusion phase; and then a plasma is applied to sterilization chamber (<NUM>). It should be understood that the entire sterilization cycle shown in <FIG> (including the above-noted variation where a subsequent vacuum then sterilization are applied) may be repeated one or more times after being completed once. In other words, a medical device may remain within sterilization chamber (<NUM>) and experience two or more iterations of the entire cycle shown in <FIG> (including the above-noted variation where a subsequent vacuum then sterilization are applied). The number of iterations may vary based on the cycle selection (block <NUM>), which may be influenced by the particular kind of medical device that is being sterilized in sterilization chamber (<NUM>).

<FIG> depicts an exemplary plot (<NUM>) showing the pressure within sterilization chamber (<NUM>) during performance of the sterilization cycle (block <NUM>) as depicted in <FIG> and as described above. As can be seen, the pressure level drops significantly and suddenly when vacuum source (<NUM>) is activated to apply vacuum (block <NUM>) to sterilization chamber (<NUM>). The pressure level then stays substantially constant while the sterilant is applied (block <NUM>) and during the subsequent, predetermined duration (block <NUM>). The pressure level then increases significantly and suddenly when venting valve (<NUM>) is activated (block <NUM>) to vent sterilization chamber (<NUM>) to atmosphere. Thus, in general terms, plot (<NUM>) shows how the pressure within sterilization chamber (<NUM>) simply toggles between a single relatively high level (i.e., atmospheric pressure) and a single relatively low level (i.e., a vacuum state). An exemplary alternative sterilization cycle is described in greater detail below with reference to <FIG>.

Upon completion of the sterilization cycle (block <NUM>), sterilization cabinet (<NUM>) may cycle the results (block <NUM>) of the sterilization cycle (block <NUM>). For instance, if the sterilization cycle (block <NUM>) was canceled or unable to complete due to error or by a user action, sterilizing cabinet (<NUM>) may remain sealed and may also display a sterilization cycle cancellation message via touch screen display (<NUM>); as well as various details relating to the sterilization cycle, such as date, time, configuration, elapsed time, sterilization cycle operator, the stage at which the sterilization cycle failed, and other information that may be used to identify why the sterilization cycle. If the sterilization cycle (block <NUM>) is completed successfully, sterilization cabinet (<NUM>) may display a notification via touch screen display (<NUM>) indicating successful completion of the sterilization cycle (block <NUM>). In addition, sterilization cabinet (<NUM>) may display information such as sterilization cycle identifier, sterilization cycle type, start time, duration, operator, and other information (<NUM>).

In addition to the foregoing, sterilizing cabinet (<NUM>) may be configured to perform sterilization processes in accordance with at least some of the teachings of <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and/or <CIT>.

As noted above, some versions of sterilizing cabinet (<NUM>) may have difficulty effectively sterilizing medical devices such as flexible endoscopes with relatively long, narrow lumens. For instance, some conventional sterilizing cabinets may be capable of sterilizing lumens that are shorter than or equal to approximately <NUM>, with a lumen diameter of approximately <NUM> or larger. It may therefore be desirable to provide a modified sterilization cycle (block <NUM>) that further promotes effective sterilization of a medical device having one or more relatively long, narrow lumens. A merely illustrative example of such a modified sterilization cycle is described in greater detail below. By way of example only, a medical device having one or more relatively long, narrow lumens may comprise a gastrointestinal endoscope that is between approximately <NUM> long and approximately <NUM> long, with a lumen having a diameter between approximately <NUM> and approximately <NUM>. It should nevertheless be understood that the process described below may also be performed on endoscopes having a length of at least approximately <NUM> or at least approximately <NUM>, with a lumen having a diameter less than approximately <NUM>.

<FIG> depicts an exemplary alternative set of sub-steps that may be performed to provide the sterilization cycle (block <NUM>) of sterilizing cabinet (<NUM>). In particular, the cycle may begin with a vacuum being applied (block <NUM>) within sterilization chamber (<NUM>). In order to provide such a vacuum, processor (<NUM>) may activate vacuum source (<NUM>) in accordance with a control algorithm. Processor (<NUM>) will then determine (block <NUM>) whether a sufficient pressure level has been reached within sterilization chamber (<NUM>). By way of example only, processor (<NUM>) may monitor data from one or more pressure sensors within sterilization chamber (<NUM>) as part of the determination step (block <NUM>). Alternatively, processor (<NUM>) may simply activate vacuum source (<NUM>) for a predetermined time period and assume that the appropriate pressure has been reached in sterilization (<NUM>) based upon the duration for which vacuum source (<NUM>) is activated. Other suitable ways in which processor (<NUM>) may determine (block <NUM>) whether a sufficient pressure level has been reached within sterilization chamber (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein. Until the appropriate pressure level has been reached within sterilization chamber (<NUM>), vacuum source (<NUM>) will remain activated.

Once sterilization chamber (<NUM>) reaches an appropriate pressure level (e.g., between approximately <NUM> Pa (<NUM> torr) and approximately <NUM> (<NUM> torr)), processor (<NUM>) then activates sterilization module (<NUM>) to apply a sterilant (block <NUM>) in sterilization chamber (<NUM>). By way of example only, the sterilant may comprise a vapor of oxidizing agent such as hydrogen peroxide, peroxy acids (e.g. peracetic acid, performic acid, etc.), ozone, or a mixture thereof. Furthermore, the sterilant may comprise chlorine dioxide or nitrogen dioxide. Various other suitable forms that the sterilant may take are described herein; while other forms will be apparent to those of ordinary skill in the art in view of the teachings herein. It should also be understood that, in some versions, the sterilant may be applied (block <NUM>) in different ways based on the user's selection of cycle (block <NUM>) as described above. Once the sterilant has been applied (block <NUM>) to sterilization chamber (<NUM>), processor (<NUM>) monitors the time (block <NUM>) to determine whether a sufficient, predetermined duration has passed. By way of example only, this predetermined duration may be anywhere from a few seconds to several minutes. Until the predetermined duration has passed, sterilization chamber (<NUM>) remains in a sealed state at the above-noted predetermined pressure level, with the applied sterilant acting upon the medical device(s) contained within sterilization chamber (<NUM>). This stage of the process may be referred to as the "transfer phase.

After the predetermined duration has passed, processor (<NUM>) activates (block <NUM>) venting valve (<NUM>) to vent sterilization chamber (<NUM>) to atmosphere. With sterilization chamber (<NUM>) being vented (block <NUM>) to atmosphere, processor (<NUM>) monitors the time (block <NUM>) to determine whether a sufficient, predetermined venting (block <NUM>) duration has passed. Until the predetermined venting (block <NUM>) duration has passed, sterilization chamber (<NUM>) remains in a vented state. After the predetermined venting (block <NUM>) duration has passed, processor (<NUM>) determines (block <NUM>) whether the sterilization cycle is complete. Examples of how this determination (block <NUM>) may be made will be described in greater detail below. It should be understood that, in the present example, the predetermined venting (block <NUM>) duration may be very brief. By way of example only, the predetermined venting (block <NUM>) duration may be approximately one second, two seconds, three seconds, four seconds, five seconds, or any other suitable duration.

If processor (<NUM>) determines (block <NUM>) that the sterilization cycle is complete, then the sterilization cycle is in fact complete (block <NUM>). However, if processor (<NUM>) determines (block <NUM>) that the sterilization cycle is not yet complete, then processor (<NUM>) closes venting valve (<NUM>) to seal (block <NUM>) sterilization chamber (<NUM>) at a pressure level that is still less than atmospheric pressure. As noted above, the venting (block <NUM>) duration is very short in this example, such that the act of sealing (block <NUM>) may occur very quickly after venting (block <NUM>) is initiated, assuming that the determinations (block <NUM>, <NUM>) confirm that sealing (block <NUM>) is in order.

Sterilization chamber (<NUM>) will remain sealed (block <NUM>) for a certain period of time. In particular, with sterilization chamber (<NUM>) being sealed (block <NUM>), processor (<NUM>) monitors the time (block <NUM>) to determine whether a sufficient, predetermined sealing (block <NUM>) duration has passed. Until the predetermined sealing (block <NUM>) duration has passed, sterilization chamber (<NUM>) remains in a sealed state. After the predetermined sealing (block <NUM>) duration has passed, processor (<NUM>) activates (block <NUM>) venting valve (<NUM>) again to vent sterilization chamber (<NUM>) to atmosphere. By way of example only, the predetermined sealing duration may be between approximately <NUM> seconds and <NUM> minutes, or more particularly between approximately <NUM> seconds and approximately <NUM> minutes, or more particularly between approximately <NUM> seconds and approximately <NUM> minutes.

At this point the process continues through the steps (blocks <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) described above, such that the process provides a series of venting (block <NUM>) and sealing (block <NUM>) of sterilization chamber (<NUM>), allowing the pressure within sterilization chamber (<NUM>) to increase in a stepwise fashion until sterilization chamber (<NUM>) reaches atmospheric pressure or some predetermined sub-atmospheric pressure. Again, each step of venting (block <NUM>) is very brief in this example, such that the pressure of sterilization chamber (<NUM>) is held at levels below atmospheric pressure during the acts of sealing (block <NUM>) (e.g., for a duration between approximately a few seconds or a few minutes). By way of example only, until the final step of venting (block <NUM>) is reached, each step of venting (block <NUM>) results in a respective increase in the pressure within sterilization chamber (<NUM>) by approximately <NUM> Pa (<NUM> torr) to approximately <NUM> Pa (<NUM> torr), or more particularly by approximately <NUM> Pa (<NUM> torr) to approximately <NUM> (<NUM> torr). Other suitable step-wise pressure increase values will be apparent to those of ordinary skill in the art in view of the teachings herein. Once sterilization cabinet (<NUM>) reaches the end of the process, venting valve (<NUM>) remains open to allow sterilization chamber (<NUM>) to remain at atmospheric pressure. The final venting step (block <NUM>) of the process may be referred to as the "diffusion phase.

In some versions, the venting duration (block <NUM>) and/or the sealing duration (block <NUM>) may vary. For instance, the venting duration (block <NUM>) and/or the sealing duration (block <NUM>) may vary based on the cycle selection (block <NUM>), which may be influenced by the particular kind of medical device that is being sterilized in sterilization chamber (<NUM>). In addition, or in the alternative, the venting duration (block <NUM>) and/or the sealing duration (block <NUM>) may vary based on where the sterilization cycle is at in the process (i.e., which venting (block <NUM>) iteration and/or which sealing (block <NUM>) iteration). Various suitable ways in which the venting duration (block <NUM>) and/or the sealing duration (block <NUM>) may vary, and various bases upon which such durations may vary, will be apparent to those of ordinary skill in the art in view of the teachings herein.

<FIG> depicts an exemplary plot (<NUM>) showing the pressure within sterilization chamber (<NUM>) during performance of the sterilization cycle (block <NUM>) as depicted in <FIG> and as described above. As can be seen, the pressure level drops significantly and suddenly when vacuum source (<NUM>) is activated to apply vacuum (block <NUM>) to sterilization chamber (<NUM>). The pressure level then stays substantially constant while the sterilant is applied (block <NUM>) and during the subsequent, predetermined duration (block <NUM>). The pressure level then increases slightly when venting valve (<NUM>) is activated (block <NUM>) to vent sterilization chamber (<NUM>) to atmosphere; yet stays at a level below atmosphere when sterilization chamber (<NUM>) is sealed (block <NUM>). The pressure level then again increases slightly when venting valve (<NUM>) is again activated (block <NUM>) to vent sterilization chamber (<NUM>) to atmosphere; yet still stays at a level below atmosphere when sterilization chamber (<NUM>) is again sealed (block <NUM>).

In the example shown in <FIG>, the cycle provides four iterations of brief venting (block <NUM>), followed by four iterations of sealing (block <NUM>), before finally venting (block <NUM>) fully to atmosphere. Thus, in general terms, plot (<NUM>) shows how the pressure within sterilization chamber (<NUM>) is increased in a step-wise fashion from a substantial vacuum state to atmospheric pressure. While <FIG> shows four iterations of brief venting and brief sealing, other processes may employ any other suitable number of iterations of brief venting and brief sealing. By way of example only, variations may provide anywhere between two iterations of brief venting and brief sealing and <NUM> iterations of brief venting and brief sealing, or more particularly between two iterations of brief venting and brief sealing and ten iterations of brief venting and brief sealing, or more particularly between three iterations of brief venting and brief sealing and seven iterations of brief venting and brief sealing.

In some instances, the process shown in <FIG> may provide more effective sterilization of some medical devices as compared to the sterilization of the same medical devices using the process shown in <FIG>. In particular, and without being limited by theory, the step-wise venting of sterilization chamber (<NUM>) may provide agitation of the contents of sterilization chamber (<NUM>), which may assist in driving the sterilant into the lumen(s) and/or other internal spaces within the medical device. Moreover, and again without being limited by theory, the step-wise venting of sterilization chamber (<NUM>) associated with the process shown in <FIG> may provide convective mass transfer of sterilant vapor molecules inside the lumen(s) and/or other internal spaces within the medical device; as compared to the simple diffusive mass transfer of vapor associated with the process shown in <FIG>. Thus, when sterilization cabinet (<NUM>) performs the process shown in <FIG>, sterilization cabinet (<NUM>) may sterilize a relatively long gastrointestinal endoscope (e.g., up to approximately <NUM> in length and with a lumen having a diameter up to approximately <NUM>); as compared to sterilization cabinet (<NUM>) performing the process shown in <FIG> , which would not be able to sterilize the long, narrow lumens of the same kind of gastrointestinal endoscope.

It should also be understood that the entire cycle shown in <FIG> may be repeated one or more times after being completed once. In other words, a medical device may remain within sterilization chamber (<NUM>) and experience two or more iterations of the entire cycle shown in <FIG>. The number of iterations may vary based on the cycle selection (block <NUM>), which may be influenced by the particular kind of medical device that is being sterilized in sterilization chamber (<NUM>).

By way of example only, an endoscope with a <NUM> long lumen may be placed in sterilization chamber (<NUM>). Vacuum may be applied (block <NUM>) to achieve a pressure level of approximately <NUM> Pa (<NUM> torr) in sterilization chamber (<NUM>). Sterilant (e.g., approximately <NUM> of a hydrogen peroxide vapor at a concentration of <NUM>%) may then be applied (block <NUM>) to provide a transfer phase lasting approximately <NUM> seconds. Sterilization chamber (<NUM>) may then be briefly vented (block <NUM>) to achieve a pressure level of approximately <NUM> Pa (<NUM> torr), and then sterilization chamber (<NUM>) may be sealed (block <NUM>). Sterilization chamber (<NUM>) may be held at the approximately <NUM> Pa (<NUM> torr) for approximately <NUM> seconds. Sterilization chamber (<NUM>) may then be briefly vented (block <NUM>) again to achieve a pressure level of approximately <NUM> Pa (<NUM> torr), and then sterilization chamber (<NUM>) may be sealed (block <NUM>) again. Sterilization chamber (<NUM>) may be held at the approximately <NUM> Pa (<NUM> torr) for approximately <NUM> seconds. Sterilization chamber (<NUM>) may then be briefly vented (block <NUM>) again to achieve a pressure level of approximately <NUM> Pa (<NUM> torr), and then sterilization chamber (<NUM>) may be sealed (block <NUM>) again. Sterilization chamber (<NUM>) may be held at the approximately <NUM> Pa (<NUM> torr) for approximately <NUM> seconds. Sterilization chamber (<NUM>) may then be briefly vented (block <NUM>) again to achieve a pressure level of approximately <NUM> Pa (<NUM> torr) (i.e., atmospheric pressure), thereby providing a diffusion phase. Of course, the foregoing is just one merely illustrative example.

In some variations, before the final step of venting (block <NUM>) is reached, additional sterilant is introduced into sterilization chamber (<NUM>) during one or more of the acts of stepwise venting (block <NUM>).

Also in some variations, a pre-plasma may be applied in the sterilization cycle (block <NUM>) to heat up the medical device contained in sterilization chamber (<NUM>). By way of example only, plasma may be applied between applying a vacuum (block <NUM>) and applying sterilant (block <NUM>). In addition, or in the alternative, a post-plasma may be applied at the end of the sterilization cycle (block <NUM>) to degrade any residual sterilant that may be adsorbed to the surface of the medical device contained in sterilization chamber (<NUM>). It should be understood that, before applying the post-plasma, a vacuum would first need to be applied to sterilization chamber (<NUM>).

As noted above, the sterilant is applied (block <NUM>) in the form of a vapor within sterilization chamber (<NUM>). By way of example only, sterilization module (<NUM>) may comprise a combination of a vaporizer and a condenser. The vaporizer may include a chamber that receives a particular concentration of sterilant solution (e.g., a liquid hydrogen peroxide solution with a concentration of approximately <NUM>% nominal, or between approximately <NUM>% and approximately <NUM>%); where the sterilant solution changes phase from liquid to vapor. The condenser may provide condensation of the sterilant solution vapor, and the concentration of the sterilant solution may be thereby increased (e.g., from approximately <NUM>% nominal to somewhere between approximately <NUM>% nominal and approximately <NUM>% nominal), by removal of water vapor. Alternatively, any other suitable methods and components may be used to apply sterilant in the form of a vapor within sterilization chamber (<NUM>). In any case, to supplement the application of the sterilant in the form of a vapor, the sterilant may also be applied (in liquid form) to the inside of lumen(s) and/or other internal spaces within the medical device and/or the outside of the medical device, before the medical device is placed in sterilization chamber (<NUM>). In such versions, the sterilant may evaporate while vacuum is applied (block <NUM>) and even after vacuum is applied (block <NUM>); and provide more concentration of sterilant to the areas of the medical device with less penetration range, thereby further promoting effective sterilization.

By way of example only, the process depicted in <FIG> may be carried out at temperatures where the walls of sterilization chamber (<NUM>) are between approximately <NUM> and approximately <NUM>, or more particularly between approximately <NUM> and approximately <NUM>, or even more particularly approximately <NUM>; and where the temperature of the medical device in sterilization chamber (<NUM>) is between approximately <NUM>-<NUM> and approximately <NUM>-<NUM>.

While the foregoing examples are described in the context of sterilizing medical devices, and particularly endoscopes, it should be understood that the teachings herein may also be readily applied in the context of sterilizing various other kinds of articles. The teachings are not limited to endoscopes or other medical devices. Other suitable articles that may be sterilized in accordance with the teachings herein will be apparent to those of ordinary skill in the art.

The following examples relate to various non-exhaustive ways in which the teachings herein may be combined or applied. It should be understood that the following examples are not intended to restrict the coverage of any claims that may be presented at any time in this application or in subsequent filings of this application. No disclaimer is intended. The following examples are being provided for nothing more than merely illustrative purposes. It is contemplated that the various teachings herein may be arranged and applied in numerous other ways. It is also contemplated that some variations may omit certain features referred to in the below examples. Therefore, none of the aspects or features referred to below should be deemed critical unless otherwise explicitly indicated as such at a later date by the inventors or by a successor in interest to the inventors. If any claims are presented in this application or in subsequent filings related to this application that include additional features beyond those referred to below, those additional features shall not be presumed to have been added for any reason relating to patentability.

Claim 1:
A method of sterilizing an article, the method comprising:
(a) receiving the article in a sterilization chamber (<NUM>);
(b) applying a vacuum to the sterilization chamber (<NUM>) to reduce the pressure within the sterilization chamber to a first pressure which is below atmospheric pressure;
(c) introducing a sterilant into the sterilization chamber (<NUM>);
(d) maintaining the first pressure in the sterilization chamber (<NUM>) for a first period of time;
(e) venting the sterilization chamber (<NUM>) to incrementally increase the pressure within the sterilization chamber (<NUM>) by <NUM> Pa to <NUM> Pa (<NUM> torr to <NUM> torr) to a second pressure, without reaching atmospheric pressure;
(f) maintaining the second pressure in the sterilization chamber (<NUM>) for a second period of time;
(g) repeating steps (e) through (f) at least once to increase the pressure in the sterilization chamber (<NUM>) to a third pressure and subsequent pressures and maintaining the third and subsequent pressures in the sterilization chamber (<NUM>) for a third and subsequent periods of time;
(h) venting the sterilization chamber (<NUM>) to increase the pressure within the sterilization chamber (<NUM>) to atmospheric pressure.