Patent Description:
<CIT> discloses a pump which generates a vacuum at a wound site via first tubing. A negative pressure circuit is defined by a canister, the first tubing and the wound site. A controller of a therapy device operates the pump to apply a first negative pressure to the entirety of the negative pressure circuit, following which ambient air is allowed to flow into the negative pressure circuit. The controller also operates the pump to apply a second negative pressure to a selected portion of the negative pressure circuit exclusive of the wound site, following which ambient air is allowed to flow into the selected portion. A quantity of fluid to be delivered to the wound site via a second tubing is determined by comparing measured parameters related to the flow of air into the negative pressure circuit to parameters measured with respect to the flow of air into the selected portion.

<CIT> discloses a wound therapy device for the treatment of wounds by means of negative pressure and fluid irrigation which includes a negative-pressure dressing, a pressure sensor which can generate pressure measurement values in order to determine the negative pressure present in the negative-pressure dressing, a drainage container for collecting liquid, and a drainage line by means of which liquid can be conveyed from the negative-pressure dressing into the drainage container. The device can further include a first pump unit for aspirating liquid from the wound space via the drainage line, an instillation container for making available an instillation fluid, an instillation line. Instillation fluid can be delivered from the instillation container into the wound space.

There is provided a negative pressure wound therapy (NPWT) system. The system includes an instillation system configured to provide instillation fluid to a wound site, and a controller. The wound site includes a wound and a wound dressing. The controller is configured to provide a first quantity of instillation fluid for a first instillation cycle. The controller is configured to determine a second quantity of instillation fluid for a second instillation cycle based on the first quantity and a reduction factor. The second quantity of instillation fluid is less than the first quantity of instillation fluid. The controller is configured to adjust an operation of the instillation system to provide the second quantity of instillation fluid to the wound site.

The reduction factor is determined based on a negative pressure of a negative pressure cycle and a time duration of the negative pressure cycle.

Referring generally to the FIGURES, systems, methods, and devices for dynamically adjusting an amount of instillation fluid provided to a wound is shown, according to some embodiments. Often times, wound volume may change due to compression set of dressings/foam, swelling of tissue, granulation tissue formation, and healing of the wound. This may result in a reduced amount of required instillation fluid (e.g., Saline) as the NPWT is performed. Users may often over-fill a fluid instillation reservoir, thereby providing an excessive amount of fluid to the wound. This may cause leakages, which can adversely affect the healing process, and can cause messes if the instillation fluid leaks onto a user. Due to these factors, the amount of instillation fluid required decreases as NPWT is performed. A controller receives various user and sensor inputs regarding a type of NPWT being performed, a duration of NPWT, a vacuum pressure of the NPWT, etc. The controller determines or selects a reduction factor based on the vacuum pressure of the NPWT and the duration of the NPWT. The controller determines a reduced instillation volume for a future fluid instillation cycle based on the reduction factor and a previously provided volume of instillation fluid. Advantageously, the controller can adjust the amount or volume of instillation fluid provided to the wound over time to reduce the likelihood of leakages. The reduction factor can take into account soak time. The reduction factor can be selected from a table, or determined using a function derived from an empirical relationship.

Referring now to <FIG>, a front view of a NPWT device <NUM> is shown, according to an exemplary embodiment. The NPWT device <NUM> includes a user interface <NUM>, buttons <NUM>, a housing <NUM>, and a controller <NUM>, according to some embodiments. In some embodiments, controller <NUM> is configured control a NPWT application system <NUM> to perform NPWT for a wound side <NUM>. In some embodiments, controller <NUM> is configured to control an operation of pump <NUM> to perform NPWT for wound side <NUM>. NPWT application system <NUM> may include pump <NUM>, instillation fluid reservoir <NUM>, removed fluid reservoir <NUM>, and pipes <NUM> and <NUM> (see <FIG>), according to some embodiments. In some embodiments, NPWT device <NUM> is configured to control an operation of a V. VERAFLO™ Therapy, a PREVENA™ Therapy, an ABTHERA™ Open Abdomen Negative Pressure Therapy, or any other NPWT (e.g., controller <NUM> is configured to adjust an operation of pump <NUM> and/or NPWT application system <NUM> to perform any of the herein mentioned NPWT). In some embodiments, NPWT device <NUM> is configured to control an operation of any devices necessary to complete any of the herein mentioned NPWT (e.g., a pump, a vacuum system, an instillation system, etc.). In some embodiments, NPWT device <NUM> is a disposable NPWT device (dNPWT) and may have reusable/disposable parts. For example, NPWT device <NUM> may be relatively lightweight (e.g., less than <NUM> pounds), and may be portable, allowing a patient to transport NPWT device <NUM> while NPWT device <NUM> still performs NPWT, according to some embodiments. Since NPWT device <NUM> may be portable, NPWT device <NUM> may draw power from a portable power source (e.g., power source <NUM>, a battery, etc.). The portable power source may have a limited energy capacity. Additionally, power source <NUM> may be a MAINS power source (e.g., a wall outlet).

User interface <NUM> is configured to display any of an alarm/alert regarding at least one of a battery capacity of NPWT device <NUM>, a leak, a pump duty cycle/pump duty value, etc., according to some embodiments. In some embodiments, user interface <NUM> is configured to provide any of a visual and an auditory alert. In some embodiments, user interface <NUM> allows a user to adjust an operation of the NPWT performed by NPWT device <NUM>. For example, the user may provide a user input to controller <NUM> through user interface <NUM> to increase a therapy pressure setpoint psp of pump <NUM>, adjust a type of NPWT performed, adjust a parameter/operation of the performed NPWT, adjust a duration of the performed NPWT, pause the NPWT, start the NPWT, transition the NPWT device <NUM> into a "change" mode (e.g., so that wound dressings can be changed), etc. In some embodiments user interface <NUM> displays an amount of instillation fluid for a user to provide. In some embodiments, user interface <NUM> receives an input of wound volume from a user. In some embodiments, user interface <NUM> is any of a resistive touch-screen interface, a surface acoustic wave touch-screen interface, a capacitive touch-screen interface, etc., configured to allow the user to control NPWT device <NUM>. In some embodiments, user interface <NUM> is controlled by buttons <NUM>. In some embodiments, buttons <NUM> are configured to control user interface <NUM> and/or to adjust an operation of the NPWT performed by NPWT device <NUM>.

User interface <NUM> is also configured to display an operational status of the performed NPWT, according to some embodiments. For example, user interface <NUM> may display any of a patient name, a responsible caregiver's name, a type of NPWT currently being performed by NPWT device <NUM>, a duration of NPWT, a time remaining in the current NPWT, a vacuum pressure of the NPWT, etc., or any other information relevant to the NPWT and/or operational status of NPWT device <NUM>. For example, user interface <NUM> is configured to display a remaining battery life of a battery (e.g., power source <NUM> as shown in <FIG>), and/or a duty cycle of the system configured to provide vacuum pressure to a wound (e.g., pump <NUM>), according to some embodiments. In some embodiments, the remaining battery life of the battery is a remaining amount of energy in the battery. In some embodiments, the remaining battery life of the battery is a remaining amount of time which NPWT device <NUM> can sustain NPWT device at a current operational status. In some embodiments, user interface <NUM> is configured to communicably connect with controller <NUM>. In some embodiments, user interface <NUM> provides controller <NUM> with any user inputs (e.g., therapy pressure setpoints, type of therapy selected, etc.). In some embodiments, controller <NUM> causes user interface <NUM> to display operational parameters of the NPWT, alarms, alerts, requests, etc..

In some embodiments, user interface <NUM> is a touch-screen. For example, user interface <NUM> may be any of a capacitive touch screen, a resistive touch screen, etc. In some embodiments, user interface <NUM> is configured to receive user inputs via the touchscreen and provide the user inputs to controller <NUM>.

Referring now to <FIG>, NPWT application system <NUM> is shown in greater detail, according to some embodiments. NPWT application system <NUM> includes pump <NUM>, instillation fluid reservoir <NUM>, removed fluid reservoir <NUM>, return tubing <NUM>, and supply tubing <NUM>, according to some embodiments. In some embodiments, pump <NUM> is configured to draw a negative pressure at a wound site <NUM> via return tubing <NUM>. In some embodiments, pump <NUM> draws the negative pressure at wound site <NUM> at the therapy pressure setpoint psp. In some embodiments, NPWT application system <NUM> is configured to provide an amount of instillation fluid (e.g., a Saline solution, etc.) to wound site <NUM> or to an inner volume <NUM> of wound <NUM> via supply tube <NUM>. In some embodiments, NPWT application system <NUM> provides the instillation fluid to the wound side <NUM> and/or to inner volume <NUM> of the wound <NUM> from instillation fluid reservoir <NUM> via supply tube <NUM>. In some embodiments, the instillation fluid is a sterile fluid which can be used for wounds which require washing to prevent infection or to reduce an amount of infection of the wound.

Supply tube <NUM> and return tube <NUM> may be any form of piping, medical tubing, flexible tubing, etc., having an inner volume configured to facilitate a flow of fluid, gas, solution, etc., therewithin and having sufficient structural strength to maintain a negative pressure (e.g., sufficient strength to not collapse while a negative pressure is produced within the inner volume). In some embodiments, supply tube <NUM> and return tube <NUM> are connected at a first end to pump <NUM>, and/or instillation fluid reservoir <NUM>, and/or removed fluid reservoir <NUM>. For example, supply tube <NUM> may be fluidly connected with instillation fluid reservoir <NUM> to provide fresh instillation fluid to wound site <NUM>. Likewise, return tube <NUM> may be fluidly connected to removed fluid reservoir <NUM> to remove fluid from wound site <NUM>. In some embodiments, NPWT application system <NUM> may supply fresh instillation fluid to wound site <NUM> via pump <NUM>. In some embodiments, pump <NUM> includes one or more pumps. For example, a separate pump may be provided to supply a positive pressure to push instillation fluid into wound site <NUM> via supply tube <NUM>. In some embodiments, pump <NUM> provides a negative pressure to wound site <NUM> via return tubing <NUM>. In some embodiments, the negative pressure provided via return tubing <NUM> provides a negative pressure at inner volume <NUM>. In some embodiments, the negative pressure of inner volume <NUM> produced by pump <NUM> draws instillation fluid from instillation fluid reservoir <NUM>. In some embodiments, a fluid regulatory device is positioned in line with supply tubing <NUM> to ensure that a sufficient volume or a sufficient volumetric flow rate of instillation fluid is provided to wound site <NUM> via supply tubing <NUM>. In some embodiments, NPWT application system <NUM> actuates between NPWT cycles and fluid instillation cycles. For example, pump <NUM> is shown receiving control signals (e.g., from controller <NUM>), according to some embodiments. In some embodiments, pump <NUM> initiates a fluid instillation cycle where instillation fluid is provided to wound site <NUM> from instillation fluid reservoir <NUM> via supply tubing <NUM>. In some embodiments, an entire volume of instillation fluid in instillation fluid reservoir <NUM> is provided to wound site <NUM>. In some embodiments, pump <NUM> automatically provides a specific amount of instillation fluid from instillation fluid reservoir <NUM> to wound site <NUM>. For example, in some embodiments instillation fluid reservoir <NUM> contains <NUM> of instillation fluid, but pump <NUM> operates to only provide <NUM> of instillation fluid to wound site <NUM>. In some embodiments, pump <NUM> performs the fluid instillation cycle by providing the instillation fluid to wound site <NUM>. In some embodiments, in response to providing X amount of instillation fluid to wound site <NUM> during the fluid instillation cycle, pump <NUM> transitions into a soak mode for a soak cycle, where the instillation fluid is allowed to soak into wound site <NUM>. In some embodiments, the soak mode includes keeping pump <NUM> in an in-operational state for a predetermined amount of time to allow the instillation fluid to sufficiently soak into wound site <NUM>. In some embodiments, in response to completing the fluid instillation cycle and the soak cycle (e.g., the soak cycle may be optional), pump <NUM> draws a negative pressure at psp for a time period Δt via return tubing <NUM>. In some embodiments, pump <NUM> draws the negative pressure at psp to perform NPWT for a NPWT cycle. In some embodiments, over the course of NPWT, pump <NUM> transitions between fluid instillation cycles and NPWT cycles, thereby providing and removing instillation fluid to and from wound site <NUM>.

Referring still to <FIG>, wound site <NUM> includes a wound <NUM>, a seal <NUM>, and foam <NUM>. In some embodiments, seal <NUM> is configured to seal along an entire perimeter of wound <NUM>. In some embodiments, seal <NUM> is configured to seal along a periwound surface <NUM> surrounding wound <NUM>. In some embodiments, seal <NUM> includes an adhesive to maintain and sealingly connect seal <NUM> to periwound surface <NUM>. In some embodiments, seal <NUM> is configured to seal along a surface of a patient surrounding periwound surface <NUM>. In some embodiments, seal <NUM> covers and seals substantially an entire surface which includes wound <NUM> therewithin. In some embodiments, seal <NUM> defines inner volume <NUM>. In some embodiments, inner volume <NUM> is defined as any volume between seal <NUM> and a surface which seal <NUM> covers. For example, inner volume <NUM> may include an inner wound volume <NUM>.

Supply tube <NUM> and return tube <NUM> are configured to sealingly connect to seal <NUM> such that they are fluidly coupled with inner volume <NUM>. In some embodiments, return tube <NUM> provides a negative pressure produced by pump <NUM> to inner volume <NUM>. In some embodiments, return tube <NUM> facilitates the egress of air, gas, or liquid within inner volume <NUM>. Likewise, supply tube <NUM> is configured to provide instillation fluid to inner volume <NUM>, according to some embodiments. In some embodiments, supply tube <NUM> is fluidly and sealingly connected with inner volume <NUM>. In some embodiments, supply tube <NUM> and return tube <NUM> are sealingly and fluidly coupled to inner volume <NUM> defined by seal <NUM> via connectors <NUM> and <NUM>, respectively.

Referring still to <FIG>, foam <NUM> is shown disposed within inner volume <NUM> of wound <NUM>, according to some embodiments. In some embodiments, foam <NUM> includes one or more pieces of foam configured to substantially fill inner volume <NUM> of wound <NUM>. In some embodiments, foam <NUM> is configured to absorb instillation fluid provided from instillation fluid reservoir <NUM> via supply tube <NUM>. In some embodiments, foam <NUM> is configured to prevent particulate matter (e.g., scar tissue, scabbing, etc.) from entering return tube <NUM>. In some embodiments, foam <NUM> is GRANUFOAM™. Foam <NUM> includes exterior surface <NUM>, according to some embodiments. In some embodiments, at least a portion of exterior surface <NUM> of foam <NUM> is substantially adjacent wound surface <NUM> of wound <NUM>. In some embodiments, an entire portion of exterior surface <NUM> of foam <NUM> is adj acent wound surface <NUM> of wound <NUM>. In some embodiments, foam <NUM> facilitates providing instillation fluid to wound <NUM> (e.g., at wound surface <NUM>). In some embodiments, exterior surface <NUM> of foam <NUM> is in contact with wound surface <NUM> of wound <NUM>.

Foam <NUM> includes edge <NUM>, according to some embodiments. In some embodiments, edge <NUM> is or defines a perimeter of foam <NUM>. Likewise, wound <NUM> includes edge <NUM>, according to some embodiments. In some embodiments, edge <NUM> of wound is or defines a perimeter of wound <NUM>. In some embodiments, wound <NUM> has a depth <NUM>. In some embodiments, a perimeter of wound <NUM> increases with depth <NUM>. For example, a perimeter of wound <NUM> may be greater than perimeter of wound <NUM> at periwound surface <NUM> (e.g., wound <NUM> may increase in overall size at various depths).

Referring now to <FIG>, wound <NUM> and foam <NUM> are shown in greater detail, according to some embodiments. As shown in <FIG>, wound <NUM> has an overall width (or length), shown as distance <NUM> and foam <NUM> has an overall width (or length), shown as distance <NUM>, according to some embodiments. In some embodiments, distance <NUM> of foam <NUM> is substantially equal to distance <NUM> of wound <NUM>. In some embodiments, distance <NUM> of foam <NUM> is substantially equal to distance <NUM> of wound <NUM> at a beginning of NPWT. For example, foam <NUM> may be packed within inner volume <NUM> of wound <NUM> such that foam <NUM> fills substantially the entire inner volume <NUM> of wound <NUM>. In some embodiments, foam <NUM> is compressible so that it can be packed into inner volume <NUM> of wound <NUM>. In some embodiments, since foam <NUM> is compressible, it can change in shape, diameter, perimeter, length, area, volume, etc., throughout the course of NPWT.

In some embodiments, a required amount of instillation fluid Vinstillation changes throughout a course of NPWT. For example, in some embodiments, inner volume <NUM> of wound <NUM> changes (e.g., decreases) due to swelling (i.e., edema) of surrounding tissue or wound tissue, healing (e.g., wound <NUM> shrinks as wound <NUM> heals), granulation formation within wound <NUM>, and compression of foam <NUM>. In some embodiments, any of the hereinabove mentioned volume changes (e.g., granulation formation, healing, edema, compression, etc.) change the required amount of instillation fluid V. For example, in some embodiments, the required amount of instillation fluid V decreases over the course of NPWT. Other systems may overfill inner volume <NUM> with instillation fluid, thereby increasing the likelihood of leaks, seal breakage, and deteriorating the quality of NPWT. Additionally, a seal leak may allow air to enter inner volume <NUM> which may deteriorate the healing process and reduce the efficiency of pump <NUM>. Advantageously, controller <NUM> is configured to decrease an amount of instillation fluid provided to inner volume <NUM> for subsequently occurring fluid instillation cycles, described in greater detail below.

The compression of foam <NUM> is a significant contributor to changes in the required amount of instillation fluid Vinstillation, according to some embodiments. In some embodiments, foam <NUM> undergoes a compression set. In some embodiments, the compression set of foam <NUM> is the most significant factor in changes to the required amount of instillation fluid Vinstillation over time. In some embodiments, the compression of foam <NUM> is predictable based on any of an amount of compression (e.g., a negative pressure at inner volume <NUM>, psp), a temperature applied to foam <NUM> (e.g., temperature of wound <NUM>, human body temperature, etc.), and time (e.g., therapy time). In some embodiments, as foam <NUM> decreases in volume, height, width, area, perimeter, etc. (e.g., as foam <NUM> compresses), a fluid capacity (Cfoam) of foam <NUM> decreases. In some embodiments, as foam <NUM> compression sets (e.g., fluid capacity Cfoam decreases), the required amount of instillation fluid Vinstillation decreases.

In some embodiments, when seal <NUM> is removed (e.g., during a dressing change, during a seal change, etc.), foam <NUM> is exposed to atmospheric pressure and expands. In some embodiments, the foam <NUM> increases back to an original height, width, volume, etc., in response to being exposed to atmospheric pressure. However, in some embodiments, foam <NUM> fails to expand back (e.g., re-inflate) to the original height, width, volume, etc. In some embodiments, foam <NUM> fails to expand back to the original height, width, volume, etc., as NPWT continues. For example, in some embodiments, foam <NUM> does not re-inflate to the original height due to instillation fluid or air present in foam <NUM> which was provided to foam <NUM> throughout the course of a previous NPWT implementation (e.g., a previous round of NPWT). Additionally, foam <NUM> may accumulate tissue matter which may reduce the fluid capacity of foam <NUM>. In some embodiments, as NPWT continues, the amount by which foam <NUM> re-inflates (e.g., how close foam <NUM> returns to the original size, volume, height, width, etc.), decreases. In some embodiments, if foam <NUM> fails to re-inflate, this affects the static volume which foam <NUM> takes before foam <NUM> appears to inflate due to fluid being delivered. In some embodiments, controller <NUM> is configured adjust the required amount of instillation fluid Vinstillation provided to wound site <NUM> by NPWT application system <NUM> to account for an amount by which foam <NUM> compresses.

Referring now to <FIG>, foam <NUM> is shown before and after compressing, according to some embodiments. <FIG> may represent foam <NUM> before foam <NUM> receives instillation fluid. <FIG> represents foam <NUM> after foam <NUM> has been exposed to negative pressure and temperatures (e.g., human body temperature) for an amount of time, according to some embodiments. As shown in <FIG>, foam <NUM> has height <NUM> and wound <NUM> has height/depth <NUM>. In some embodiments, height <NUM> of foam <NUM> is initially substantially equal to height/depth <NUM> of wound <NUM>. In some embodiments, after foam <NUM> has been exposed to negative pressure and temperature (<FIG>), for an amount of time (e.g., a therapy time), height <NUM> of foam decreases. As shown in <FIG>, height <NUM> of foam <NUM> is less than height/depth <NUM> of wound <NUM> after foam <NUM> has been exposed to negative pressure and temperature for the amount of time, according to some embodiments. In some embodiments, the decrease in height <NUM> of foam <NUM> affects the required amount of instillation fluid Vinstillation to be provided to wound site <NUM>.

Referring now to <FIG>, width <NUM> of foam <NUM> may decrease similar to the decrease in height <NUM> of foam <NUM>, according to some embodiments. In <FIG>, foam <NUM> has an overall width <NUM> substantially equal to an overall width <NUM> of wound <NUM>, according to some embodiments. In some embodiments, <FIG> illustrate foam <NUM> before foam <NUM> has been exposed to negative pressure and a temperature for an amount of time. In some embodiments, as shown in <FIG>, an overall perimeter <NUM> of foam <NUM> is initially substantially equal to perimeter <NUM> of wound <NUM>. In some embodiments, after foam <NUM> has been exposed to negative pressure and temperature for some amount of time, overall perimeter <NUM> of foam <NUM> decreases as shown in <FIG>. In some embodiments, the decrease in perimeter <NUM> of foam <NUM> is due to a decrease in width <NUM> of foam <NUM>. As shown in <FIG>, perimeter <NUM> of foam <NUM> has decreased an amount such that perimeter <NUM> is offset a distance <NUM> from perimeter <NUM> of wound <NUM>. In some embodiments, the decrease in height <NUM> and/or width <NUM> and/or perimeter <NUM> of foam <NUM> affects the required amount of instillation fluid Vinstillation which should be provided to wound site <NUM>. In some embodiments, the decrease in height <NUM>, perimeter <NUM>, and/or width <NUM> is related to the fluid capacity Cfoam of foam <NUM>. For example, height <NUM> may decrease as well as perimeter <NUM>, due to buildup of wound tissue matter within foam <NUM> which decreases the fluid capacity Cfoam of foam <NUM>. In some embodiments, the fluid capacity Cfoam changing indicates a required change in the required amount of instillation fluid Vinstillation for wound <NUM>.

Referring now to <FIG>, changes in overall size of wound <NUM> are shown, according to some embodiments. In some embodiments, wound <NUM> may change in overall size due to any of swelling, edema, and healing. In some embodiments, changes in overall size of wound <NUM> decreases inner volume <NUM> of wound <NUM>. In some embodiments, as inner volume <NUM> of wound <NUM> change (e.g., decreases), the required amount of instillation fluid Vinstillation which should be provided to wound site <NUM> changes (e.g., decreases). In some embodiments, inner volume <NUM> of wound <NUM> decreases due to granulation formation.

Referring now to <FIG>, wound <NUM> is shown at an initial state, according to some embodiments. In some embodiments, the initial state of wound <NUM> as shown in <FIG> is a state of wound <NUM> before NPWT has begun. Wound <NUM> has an overall width <NUM> at the initial state, according to some embodiments. In some embodiments, wound <NUM> has an overall height <NUM> at the initial state. As shown in <FIG>, as NPWT is performed on wound <NUM>, at least one of overall width <NUM> and overall height <NUM> of wound decreases, according to some embodiments. In some embodiments, the decrease in either overall height <NUM> and overall width <NUM> of wound <NUM> decreases inner volume <NUM> of wound <NUM>. In some embodiments, a decrease in inner volume <NUM> of wound <NUM> decreases the required amount of instillation fluid Vinstillation which should be provided to wound site <NUM> via supply tube <NUM>. In some embodiments, controller <NUM> is configured to predict and offset the required amount of instillation fluid Vinstillation with respect to time to account for decreases in volume <NUM> of wound <NUM> as wound <NUM> heals. Inner volume <NUM> of wound <NUM> may decrease or change for any of the reasons listed herein above (e.g., healing, granulation tissue formation, swelling, edema, etc.), according to some embodiments.

As shown in <FIG>, perimeter <NUM> of wound <NUM> may change as NPWT continues (e.g., due to edema, healing of wound <NUM>, granulation tissue formation, swelling, etc.), according to some embodiments. In some embodiments, perimeter <NUM> of wound <NUM> decreases as NPWT continues due to any of the hereinabove mentioned factors. In some embodiments, as perimeter <NUM> of wound <NUM> decreases, the required amount of instillation fluid Vinstillation of wound <NUM> decreases. In some embodiments, foam <NUM> changes (e.g., decreases) in size, shape, perimeter, width, height, etc., as wound <NUM> changes. For example, as shown in <FIG>, perimeter <NUM> of wound <NUM> has decreased an offset distance <NUM> relative to an initial perimeter <NUM> of wound <NUM>, according to some embodiments. Likewise, perimeter <NUM> of foam <NUM> has also decreased, according to some embodiments.

Controller <NUM> is configured to adjust the required amount of instillation fluid Vinstillation provided to wound site <NUM> to account for any of volumetric changes of wound <NUM> and volumetric changes of foam <NUM>, according to some embodiments. In some embodiments, controller <NUM> uses an empirical relationship to determine the required amount of instillation fluid Vinstillation and/or an amount to increase or decrease the required amount of instillation fluid Vinstillation to account for the changes in volume of wound <NUM> and/or the changes in volume of foam <NUM>. In some embodiments, the changes in volume of foam <NUM> are due to compression setting of foam <NUM> as described above. In some embodiments, changes in volume of wound <NUM> are due to any of edema, swelling, wound healing, granulation tissue formation, etc..

Referring now to <FIG>, graphs <NUM> and <NUM> show changes in height of foam <NUM> and changes in volume of wound <NUM>, according to some embodiments. In some embodiments, the empirical relationships shown in graphs <NUM> and <NUM> are used to determine factors which controller <NUM> uses to determine the required amount of instillation fluid Vinstillation. In some embodiments, the empirical relationships shown in graphs <NUM> and <NUM> are used to determine an amount to increase or decrease the required amount of instillation fluid Vinstillation. In some embodiments, a factor amount to increase or decrease the required amount of instillation fluid Vinstillation is referred to as the reduction factor θ.

Referring now to <FIG>, graph <NUM> shows the changes of height <NUM> of foam <NUM> (Y-axis) with respect to therapy time (X-axis), according to some embodiments. In some embodiments, graph <NUM> includes scatter data <NUM>. In some embodiments, scatter data <NUM> is empirical data determined through testing. In some embodiments, for example, scatter data <NUM> is determined by measuring an initial value of height <NUM> of foam <NUM>, performing NPWT for some amount of time, and measuring the value of height <NUM> of foam <NUM> after NPWT has been performed. For example, a single piece of foam <NUM> with an initial height <NUM> value of <NUM> may be exposed to a Saline solution (e.g., instillation fluid) at a negative pressure of <NUM> mmHg (e.g., psp) and at a temperature of <NUM> degrees Celsius (approximately human body temperature) for a predetermined amount of time (e.g., <NUM> hours), according to some embodiments. After the predetermined amount of time has elapsed, another value of height <NUM> of foam <NUM> is recorded (e.g., the value of height <NUM> of foam <NUM> is <NUM>), according to some embodiments. This process may be repeated to determine data points which relate height <NUM> of foam <NUM> to therapy time (e.g., to determine data point <NUM>) for a particular set of temperature and pressure (psp) conditions. For example, in some embodiments, after the foam with the initial value of height <NUM> of <NUM> was exposed to the same conditions for another <NUM> hours, the final value of height <NUM> was recorded at <NUM>, according to some embodiments. This yields the datapoints: h = <NUM> at t = <NUM> hours, h = <NUM> at t = <NUM> hours, and h = <NUM> at t = <NUM> hours for foam <NUM> when tested at <NUM> mmHg and <NUM> degrees Celsius, where h is height <NUM> of foam <NUM>, according to some embodiments. This test may be continued to determine additional data points for various combinations of temperature and pressure, according to some embodiments. For example, this test may be performed for a negative pressure, psp, of <NUM> mmHg, <NUM> mmHg, <NUM> mmHg, etc., or any other psp value which is typically used during NPWT, according to some embodiments.

Referring still to <FIG>, a linear trendline <NUM> or a non-linear relationship <NUM> can be determined based on scatter data <NUM> as determined using the testing procedure above, according to some embodiments. In some embodiments, a linear trendline <NUM> and/or a non-linear relationship <NUM> can be determined for each set of scatter data resulting from various test parameters (e.g., various values of psp, various temperature values, etc. In some embodiments, the relationship between change in height h (i.e., height <NUM> of foam <NUM>) and therapy time has the relationship: <MAT> where ffoam is a relationship between Δh and T, Δt, and psp, T is a temperature which the foam is exposed to during testing, Δt is an elapsed amount of therapy time, and psp is a pressure to which the foam is exposed during testing. In some embodiments, ffoam depends on various properties of the foam. In some embodiments, ffoam is a linear relationship between Δt and Δh. In some embodiments, ffoam is a non-linear relationship between Δt and Δh. In some embodiments, ffoam is determined for each combination of T and psp which may be used during NPWT. In some embodiments, multiple tests are performed for various sets of T and psp and a multi-variable regression is performed to determine ffoam for Δh in terms of T, Δt, and psp.

In some embodiments, the change in height Δh of foam <NUM> due to NPWT is proportional to fluid capacity of foam <NUM> (i.e., Cfoam ∝ Δh). In some embodiments, as the height h of foam <NUM> decreases, the fluid capacity Cfoam also decreases. In some embodiments, as the fluid capacity Cfoam decreases (e.g., due to compression set, tissue matter within foam <NUM>, etc.), the required amount of instillation fluid Vinstillation also decreases. In this way, as foam <NUM> changes over time during NPWT, the required amount of instillation fluid Vinstillation also changes over time, according to some embodiments. Controller <NUM> is configured to decrease the amount of instillation fluid Vinstillation for subsequently occurring fluid instillation cycles based on Δt and psp, according to some embodiments.

Referring now to <FIG>, graph <NUM> shows the changes of inner volume <NUM> (Vwound) of wound <NUM> (Y-axis) with respect to therapy time (X-axis), according to some embodiments. In some embodiments, inner volume <NUM> of wound <NUM> is directly correlated to a fluid capacity of wound <NUM> (e.g., an amount of instillation fluid which wound <NUM> can contain). In some embodiments, graph <NUM> includes scatter data <NUM>. In some embodiments, scatter data <NUM> is a result of various tests. For example, scatter data <NUM> may represent values of inner volume <NUM> of wound <NUM> as measured throughout a NPWT application, according to some embodiments. In some embodiments, scatter data <NUM> is collected for various NPWT applications with various temperature T (e.g., various human body temperatures) and various negative pressure setpoints psp. In some embodiments, a linear trendline <NUM> is fit to scatter data <NUM> to determine a relationship between inner volume <NUM> of wound <NUM> and therapy time. In some embodiments, a non-linear relationship <NUM> is determined based on scatter data <NUM> to determine a non-linear relationship between inner volume <NUM> of wound <NUM> and therapy time. In some embodiments, trendline <NUM> and/or non-linear relationship <NUM> are used to predict an amount by which inner volume <NUM> of wound <NUM> decreases as NPWT is performed. Advantageously, controller <NUM> can use the predicted change in inner volume <NUM> of wound <NUM> to determine changes to the required amount of instillation fluid Vinstillation.

In some embodiments, any of the relationships described herein above with reference to graphs <NUM> and <NUM> are used to determine the factor(s) θ which controller <NUM> uses to adjust the required amount of instillation fluid Vinstillation. In some embodiments, controller <NUM> stores one or more values of θ for various NPWT parameters (e.g., various psp values, various T values, combinations of the various psp and T values, etc.) and uses the one or more values of θ to determine adjusted amounts of instillation fluid Vinstillation. In some embodiments, controller <NUM> uses a function to determine the factor θ based on various NPWT parameters. In some embodiments the values of the factor θ are determined based on any of the relationships as shown in graphs <NUM> and <NUM>.

Referring now to <FIG>, controller <NUM> is shown in greater detail, according to some embodiments. Controller <NUM> is configured to determine changes in the required amount of instillation fluid Vinstillation to ensure that an excess of instillation fluid is not provided to wound site <NUM>, according to some embodiments. In some embodiments, controller <NUM> advantageously reduces the likelihood that an excessive amount of instillation fluid (e.g., saline solution) is introduced to wound site <NUM>. Some systems may require a user to manually determine an amount of instillation fluid to be added to wound site <NUM>. Advantageously, controller <NUM> is configured to automatically adjust the amount of instillation fluid introduced to wound site <NUM> to prevent leakages from occurring and to improve quality of the NPWT, according to some embodiments.

Controller <NUM> is configured to control an operation of pump <NUM> to perform the NWPT, according to some embodiments. In some embodiments, controller <NUM> is configured to control pump <NUM> and/or NPWT application system <NUM> to provide the determined instillation volume Vinstillation to wound site <NUM> for a fluid instillation cycle. Controller <NUM> is shown to include a processing circuit, shown as processing circuit <NUM>, according to some embodiments. Processing circuit <NUM> may be configured to perform some or all of the functionality of controller <NUM>. Processing circuit <NUM> is shown to include a processor, shown as processor <NUM>. Processor <NUM> may be a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Processor <NUM> may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. Processor <NUM> also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, particular processes and methods may be performed by circuitry that is specific to a given function. Processing circuit <NUM> also include memory, shown as memory <NUM>. Memory <NUM> (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. Memory <NUM> may be or include volatile memory or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein. According to an exemplary embodiment, the memory <NUM> is communicably connected to the processor <NUM> via processing circuit <NUM> and includes computer code for executing (e.g., by the processing circuit or the processor) the one or more processes described herein.

Referring still to <FIG>, controller <NUM> is shown to include a power interface, shown as power interface <NUM>, according to an exemplary embodiment. Power interface <NUM> is configured to draw power supplied by a power source, shown as power source <NUM>, to power controller <NUM>, according to some embodiments. In some embodiments, power source <NUM> is any kind of permanent and/or temporary power source. In some embodiments, power source <NUM> is a battery. In some embodiments, power interface <NUM> is a connection port for a permanent power source (e.g., AC power and/or DC power) such as a wired 24VAC connection. In other embodiments, power interface <NUM> includes both a port for permanent power and/or a power circuit configured to receive and transform power from power source <NUM>. In some embodiments, power interface <NUM> is configured to receive power from both a permanent power source (e.g., an outlet) and a temporary power source (e.g., a battery). Power interface <NUM> may include any number of electrical components such as resistors, transistors, capacitors, inductors, diodes, transformers, transistors, switches, etc., necessary to receive, transform, and supply power to controller <NUM>, according to some embodiments. In some embodiments, if power interface <NUM> is configured to receive power from a temporary power source (e.g., if power source <NUM> is a battery), power interface <NUM> may output power level data of power source <NUM> to processing circuit <NUM>. The power level data may indicate an amount of energy remaining in power source <NUM> (e.g., a number of kW-hrs remaining in power source <NUM>). In some embodiments, power source <NUM> is a replaceable power source (e.g., a battery). In some embodiments, power source <NUM> is one or more disposable batteries. For example, power source <NUM> is one or more disposable <NUM>-volt batteries, according to some embodiments. In some embodiments, power source <NUM> is one or more rechargeable batteries. In some embodiments, power source <NUM> is configured to be temporarily disconnected from power interface <NUM> when the replaceable power source must be replaced (e.g., if power source <NUM> is one or more replaceable batteries, power source <NUM> may be disconnected when the battery level is low and the batteries must be replaced).

Referring still to <FIG>, controller <NUM> is shown to include communications interface <NUM>, according to some embodiments. Communications interface <NUM> is configured to facilitate communication between controller <NUM> and various external devices, sensors, systems, etc. Communications interface <NUM> is configured to receive inputs from at least one of pump <NUM>, user interface <NUM>, a sensor, a device, etc. according to some embodiments. In some embodiments, communications interface <NUM> receives commands and/or requests from user interface <NUM>. For example, user interface manager <NUM> may receive a command from user interface <NUM> via communications interface <NUM> to transition NPWT device <NUM> between various modes of operation, or to adjust an operational characteristic of the NPWT being performed by NPWT device <NUM> (e.g., increasing a pressure setpoint, increasing an amount of therapy time, pausing therapy, etc.). Communications interface <NUM> is also configured to receive information from pump <NUM> regarding an actual therapy pressure or a pump duty, according to some embodiments. In some embodiments, communications interface <NUM> is configured to facilitate communications between user interface <NUM> and user interface manager <NUM>. Communications interface <NUM> may include any wired or wireless interfaces. For example, communications interface <NUM> may include a Universal Serial Bus interface, according to some embodiments. In other embodiments, communications interface <NUM> includes one or more wireless transceivers configured to wirelessly communicably connect controller <NUM> with various external devices, systems, sensors, etc. (e.g., user interface <NUM> and pump <NUM>). In some embodiments, communications interface <NUM> is configured to facilitate communications between control signal manager <NUM> and pump <NUM>. For example, control signal manager <NUM> may determine control signals for pump <NUM> and/or NPWT application system <NUM>. In some embodiments, communications interface <NUM> facilitates communications between pump <NUM> and control signal manager <NUM> such that control signal manager <NUM> can output control signals to pump <NUM> to adjust an operation of pump <NUM>.

Referring still to <FIG>, memory <NUM> is shown to include user interface manager <NUM>, according to some embodiments. In some embodiments, user interface manager <NUM> is configured to receive one or more inputs from user interface <NUM>. In some embodiments, user interface manager <NUM> is configured to receive one or more therapy parameters from user interface <NUM> via communications interface <NUM>. The one or more therapy parameters may include any of a type of therapy selected, a therapy pressure setpoint psp, a temperature (e.g., a local temperature at wound site <NUM>), a total therapy time ttotal, and a volume of wound <NUM> Vwound. In some embodiments, user interface manager <NUM> receives a therapy selection from user interface <NUM> via communications interface <NUM> and determines one or more ofpsp, T, ttotal, Vwound, etc. In some embodiments, user interface manager <NUM> provides any of psp, T, Vwound, and ttotal to instillation volume manager <NUM>. In some embodiments, instillation volume manager <NUM> uses any of these inputs to determine an instillation fluid quantity (i.e., volume) Vinstillation using any of psp, T, Vwound, and ttotal. In some embodiments, T is assumed to be normal body temperature of a human. In some embodiments, psp is a negative pressure setpoint input by a user via user interface <NUM>. In some embodiments, psp is a negative pressure setpoint as determined by user interface manager <NUM> based on the type of therapy selected or received from user interface <NUM>.

Referring still to <FIG>, memory <NUM> is shown to include timer <NUM>, according to some embodiments. In some embodiments, timer <NUM> is configured to track an elapsed amount of time for which NPWT has been performed. For example, timer <NUM> may record a start time, and compare the start time of NPWT to a present time value to determine a total amount of time over which NPWT has been performed, according to some embodiments. In some embodiments, timer <NUM> is configured to provide instillation volume manager <NUM> and/or wound volume manager <NUM> with the total amount of elapsed time. In some embodiments, the elapsed time is Δt. In some embodiments, timer <NUM> keeps track of times at which therapy is paused (e.g., for dressing changes). In some embodiments, timer <NUM> receives psp from any of user interface manager <NUM>, communications interface <NUM>, etc. In some embodiments, if psp changes (e.g., is increased from <NUM> mmHg to <NUM> mmHg), timer <NUM> records a time at which psp was changed. In some embodiments, timer <NUM> tracks an amount of time for which NPWT has been provided at a specific therapy pressure psp. For example, if NPWT device <NUM> provides NPWT at <NUM> mmHg for a first time period, and <NUM> mmHg for a second time period, timer <NUM> tracks the amount of time of the first time period and the second time period, according to some embodiments. In some embodiments, timer <NUM> is configured to provide instillation volume manager <NUM> with an elapsed amount of time Δt since the previous pressure setpoint psp change. In some embodiments, timer <NUM> is configured to identify events (e.g., therapy start time, pressure setpoint psp changes, etc.), and record an amount of time between sequentially occurring events Δt and/or an amount of time elapsed since a previously occurring event Δt. Timer <NUM> may provide instillation volume manager <NUM> and/or wound volume manager <NUM> with Δt.

Referring still to <FIG>, memory <NUM> is shown to include wound volume manager <NUM>, according to some embodiments. In some embodiments, wound volume manager <NUM> is configured to determine a volume of wound <NUM> Vwound. In some embodiments, wound volume manager <NUM> is configured to provide instillation volume manager <NUM> with the determined volume of wound <NUM>, Vwound. In some embodiments, wound volume manager <NUM> determines Vwound based on any of an elapsed time since an initiation of NPWT Δt, an amount of elapsed time Δt since a therapy pressure setpoint change psp, an initial wound volume Vwound,initial, and an empirical relationship. In some embodiments, Vwound,initial is provided to wound volume manager <NUM> via user interface <NUM> and communications interface <NUM> at a beginning of NPWT. For example, a user may measure an initial volume of wound <NUM> and input the initial volume of wound <NUM> via user interface <NUM>. In some embodiments, wound volume manager <NUM> uses the empirical relationship described in greater detail above with reference to <FIG> to determine a current volume of wound <NUM>. For example, wound volume manager <NUM> may receive an elapsed time since an initiation of NPWT, a pressure at which NPWT is being performed psp, and use the empirical relationship to determine a present value of Vwound. In some embodiments, wound volume manager <NUM> determines an amount by which Vwound has decreased over a time period (e.g., since an initiation of NPWT). In some embodiments, wound volume manager <NUM> provides instillation volume manager <NUM> with Vwound.

Referring still to <FIG>, memory <NUM> is shown to include instillation volume tracker <NUM>, according to some embodiments. In some embodiments, instillation volume tracker <NUM> is configured to record/track instillation volumes Vinstillation over previous cycles of NPWT. For example, instillation volume tracker <NUM> may record the amount of instillation fluid Vinstillation provided to wound site <NUM> during a previous fluid instillation cycle (e.g., at fluid instillation cycle k - <NUM>), according to some embodiments. In some embodiments, instillation volume tracker <NUM> records and tracks an amount of instillation fluid (e.g., Vinstillation) provided to wound <NUM> over a previous fluid instillation cycle. In some embodiments, instillation volume tracker <NUM> receives an instillation volume amount Vinstillation(k) as determined by instillation volume manager <NUM> for a current fluid instillation cycle (e.g., a current cycle of NPWT, a current fluid instillation cycle, etc.). For example, if NPWT device <NUM> is currently set to instill X<NUM> cubic centimeters of instillation fluid over an instillation fluid cycle and then provide NPWT at psp = <NUM> mmHg for a <NUM> hour NPWT cycle, instillation volume tracker <NUM> records the X<NUM> cubic centimeters of instilled fluid for the first fluid instillation cycle. If NPWT device <NUM> is set to next instill X<NUM> cubic centimeters of instillation fluid over a second instillation fluid cycle and then provide NPWT at psp = <NUM> mmHg for a second <NUM> hour NPWT cycle, instillation volume tracker <NUM> can provide the X<NUM> cubic centimeters to instillation volume manager <NUM> as the previously instilled quantity of instillation fluid Vinstillation(k - <NUM>) which can be used by instillation volume manager <NUM> to determine X<NUM> for the second instillation fluid cycle. When the second <NUM> hour NPWT cycle is completed, instillation volume tracker <NUM> may store X<NUM> as the previously instilled quantity of instillation fluid Vinstillation(k - <NUM>) and may store the instillation quantity X<NUM> from the first cycle as Vinstillation(k - <NUM>). In this way, instillation volume tracker <NUM> records instillation quantity for previously completed NPWT or fluid instillation cycles, according to some embodiments. In some embodiments, instillation volume tracker <NUM> also records and provides instillation volume manager <NUM> with a time duration Δt of a previously performed NPWT cycle, and a NPWT pressure setpoint psp (k - <NUM>) of the previously performed NPWT cycle.

Referring still to <FIG>, memory <NUM> is shown to include instillation volume manager <NUM>, according to some embodiments. In some embodiments, instillation volume manager <NUM> is configured to determine an amount of instillation fluid Vinstillation which should be provided to wound site <NUM>. In some embodiments, instillation volume manager <NUM> is configured to determine Vinstillation based on any of an amount of elapsed therapy time (e.g., Δt), a therapy pressure setpoint psp, a type of NPWT being performed, and reduction factor Θ. In some embodiments, instillation volume manager <NUM> receives the reduction factor Θ from instillation reduction database <NUM>. In some embodiments, instillation reduction database <NUM> includes a look-up table of various values for Θ for different combinations of T and psp. In some embodiments, the various values of θ as stored in instillation reduction database <NUM> and provided to instillation volume manager <NUM> are determined using empirical test results, as described in greater detail above.

In some embodiments, instillation volume manager <NUM> determines a quantity (e.g., volume, amount, etc.) of instillation fluid Vinstillation(k) to be provided to wound <NUM> for a present instillation cycle k. In some embodiments, for a first fluid instillation cycle, instillation volume manager <NUM> determines that the first quantity of instillation fluid is Vwound as determined by wound volume manager <NUM> or received from user interface manager <NUM>. In some embodiments, for subsequently occurring fluid instillation cycles, instillation volume manager <NUM> determines the quantity of instillation fluid Vinstillation(k) to be provided to wound <NUM> for the present instillation cycle k based on the instillation fluid provided to wound <NUM> for the previous fluid instillation cycle. In some embodiments, instillation volume manager <NUM> determines the quantity of instillation fluid Vinstillation(k) to be provided to wound <NUM> for the present instillation cycle k using the equation: <MAT> where Vinstillation(k) is an amount of instillation fluid (e.g., in cubic centimeters) to be provided to wound <NUM> for a current fluid instillation cycle k, θ is a reduction factor, and Vinstillation(k - <NUM>) is an amount of instillation fluid (e.g., in cubic centimeters, in mL, etc.) which was provided to wound <NUM> for a previous fluid instillation cycle k - <NUM>, according to some embodiments. In some embodiments, the term θ · Vinstillation(k - <NUM>) is an amount by which to decrease the value of the previously provided instillation fluid quantity Vinstillation(k - <NUM>). In some embodiments, the reduction factor θ is a normalized value (e.g., between <NUM> and <NUM>). In some embodiments, the reduction factor θ is a percentage value. In some embodiments, the reduction factor θ is selected by instillation volume manager <NUM> from instillation reduction database <NUM>. In some embodiments, the reduction factor θ is selected or determined based on a previous NPWT cycle. In some embodiments, the reduction factor θ is selected or determined based on both a NPWT pressure setpoint psp of a previous NPWT cycle, and an amount of time Δt for which the NPWT at psp was provided to wound <NUM>. In some embodiments, the reduction factor θ is determined using a function: <MAT> where Θ is the reduction factor, psp is the NPWT pressure setpoint of the previous negative pressure cycle, Δt is a time duration over which NPWT was performed at psp for the previous NPWT cycle, and freduc is a relationship between θ and psp and Δt. In some embodiments, freduc is a function determined based on empirical data. In some embodiments, freduc is determined based on an estimated amount of change in Vwound over the time period Δt at the NPWT pressure setpoint psp (e.g., due to edema, swelling, changes in foam <NUM>, healing, etc.).

In some embodiments, the reduction factor θ is selected from a table of values stored in instillation reduction database <NUM>. For example, instillation reduction database <NUM> may include table <NUM> as shown in <FIG>. Table <NUM> includes a column <NUM> which represents the pressure setpoint psp of the previously provided NPWT, as well as a column <NUM> of the time duration Δt over which the NPWT was provided at psp. Table <NUM> includes column <NUM> with values of the reduction factor θ, according to some embodiments. In some embodiments, instillation volume manager <NUM> retrieves an appropriate value of the reduction factor θ from table <NUM> as stored in instillation reduction database <NUM> based on psp and Δt. For example, as shown in <FIG>, if NPWT was previously provided to wound <NUM> at a vacuum pressure of psp = <NUM> mmHg for Δt = <NUM> hours, the reduction factor θ is <NUM> (or a <NUM>% reduction, according to some embodiments. In some embodiments, instillation volume manager <NUM> receives the previously provided quantity/volume of instillation fluid Vinstillation(k - <NUM>) from instillation volume tracker <NUM>. For example, if at a previous fluid instillation cycle <NUM><NUM> of instillation fluid was provided to wound <NUM>, and the reduction factor θ is <NUM> (e.g., for psp = <NUM> and Δt = <NUM> hrs), instillation volume manager <NUM> determines the volume of instillation fluid for a current fluid instillation cycle: <MAT> according to some embodiments.

In some embodiments, instillation volume manager <NUM> receives an estimated/approximated current volume of wound <NUM> from wound volume manager <NUM>. In some embodiments, instillation volume manager <NUM> receives the estimated/approximated current volume of wound <NUM> from user interface manager <NUM>. In some embodiments, instillation volume manager <NUM> uses the estimated current volume of wound <NUM> to determine the reduction factor θ. In some embodiments, instillation volume manager <NUM> determines the reduction factor θ based on the wound volume Vwound using the function: <MAT> where Vwound(k) is the estimated volume of wound <NUM> received from wound volume manager <NUM> or user interface <NUM> at a present fluid instillation cycle k, Vwound(k - <NUM>) is a previously estimated volume of wound <NUM> at a prior fluid instillation cycle, and freduc,Vwound is a function which relates θ to Vwound(k) and Vwound(k - <NUM>).

In some embodiments, a NPWT cycle may include changes in psp at various points in the NPWT cycle. Graph <NUM> of <FIG> illustrates a NPWT cycle <NUM> having multiple stages, according to some embodiments. Graph <NUM> illustrates provided negative pressure psp (Y-axis) with respect to elapsed time (X-axis), according to some embodiments. In some embodiments, NPWT cycle <NUM> includes a first portion <NUM>, a second portion <NUM>, and a third portion <NUM>. First portion <NUM> has a time duration <NUM> (i.e., Δt<NUM>) at psp = p<NUM>, second portion <NUM> has a time duration <NUM> (i.e., Δt<NUM>) at psp = p<NUM>, and third portion <NUM> has a time duration <NUM> (i.e., Δt<NUM>) at psp = p<NUM>, according to some embodiments. In some embodiments, psp increases from first portion <NUM> to second portion <NUM>, and decreases from second portion <NUM> to third portion <NUM>. In some embodiments, instillation volume manager <NUM> treats each of portions <NUM>-<NUM> as individual portions and determines Vinstillation for a fluid instillation cycle following NPWT cycle <NUM> by determining a reduction factor θ for each portion. In some embodiments, time durations <NUM>-<NUM> are recorded by timer <NUM>. In some embodiments, instillation volume manager <NUM> uses the equation: <MAT> where n is a number of portions/sections of a NPWT cycle which occurred between instillation cycle k and instillation cycle k - <NUM> (e.g., <NUM> for the example as shown in <FIG>), and θi is the reduction factor for each of the portions/sections of the NPWT cycle (e.g., NPWT cycle <NUM>).

For NPWT cycle <NUM>, the above equation reduces to: <MAT> where θ<NUM> = freduc(Δt<NUM>, p<NUM>), θ<NUM> = freduc(Δt<NUM>, p<NUM>), and θ<NUM> = freduc(Δt<NUM>,p<NUM>). Each of the reduction factors θ<NUM>, θ<NUM>, and θ<NUM> may be determined using a function freduc or by selecting an appropriate reduction factor from instillation reduction database <NUM> based on Δt and psp. The above equation reduces to: <MAT> according to some embodiments. In some embodiments, n indicates a number of portions of a NPWT cycle between the fluid instillation cycle k and the fluid instillation cycle k - <NUM>. In some embodiments, n is determined based on a number of changes of the NPWT pressure psp as identified by timer <NUM>. In some embodiments, instillation volume manager <NUM> determines a number of portions of a NPWT cycle as: <MAT> where #psp changes is a number of changes of psp over the entire NPWT cycle. If, however, the NPWT cycle is performed at a single pressure (e.g., psp = <NUM> mmHg), #psp changes is zero, and n is one. In some embodiments, the number of portions of the NPWT cycle indicates a number of reduction factors θ.

In some embodiments, for a NPWT cycle (e.g., NPWT cycle <NUM>) having multiple sections, instillation volume manager <NUM> treats each section/portion as an individual NPWT cycle. For example, instillation volume manager <NUM> may determine a reduction factor θ for each portion/section, and determine an adjusted volume of instillation fluid Vinstillation for each section/portion. However, the "previous" instillation fluid volume Vinstillation(k - <NUM>) for subsequently occurring portions/sections is set equal to the instillation fluid Vinstillation for the immediately prior occurring portion/section, according to some embodiments. For example, for NPWT cycle <NUM>, section <NUM> has reduction factor θ<NUM>, section <NUM> has reduction factor θ<NUM>, and section <NUM> has reduction factor θ<NUM>, according to some embodiments. In some embodiments, instillation volume manager <NUM> uses the equation: <MAT> where n is a number of sections of the NPWT cycle due to pressure setpoint changes, Vinstillation(k - <NUM>) is an instillation fluid volume provided to the wound during a fluid instillation cycle prior to the NPWT cycle, and Vinstillation(k) is the amount of instillation fluid to be provided to the wound at a fluid instillation cycle following the NPWT cycle, according to some embodiments.

For example, if Δt<NUM> is <NUM> hours and p<NUM> is <NUM> mmHg, Δt<NUM> is <NUM> hours and p<NUM> is <NUM> mmHg, and Δt<NUM> is <NUM> hours and p<NUM> is <NUM> mmHg, θ<NUM> = <NUM>, θ<NUM> = <NUM>, and θ<NUM> = <NUM> as determined by referencing table <NUM>, according to some embodiments. Assuming, for the sake of example, that the previously provided instillation volume Vinstillation(k - <NUM>) was <NUM>, the instillation volume to be provided for the fluid instillation cycle following NPWT cycle <NUM> can be determined as: <MAT> according to some embodiments.

Alternatively, the instillation fluid volume Vinstillation(k) can be determined using the equation: <MAT> which becomes: <MAT> according to some embodiments.

In some embodiments, for a NPWT cycle with multiple portions due to changes in the pressure setpoint psp, an average pressure across the entire NPWT cycle is determined. For example, for NPWT cycle <NUM> as shown in <FIG>, an average setpoint pavg can be determined as: <MAT> which can be generalized as: <MAT> according to some embodiments.

In some embodiments, the instillation volume Vinstillation(k) for a fluid instillation cycle following NPWT cycle <NUM> can then be determined using the equation: <MAT> where θavg is a reduction factor selected or determined based on an overall Δt of NPWT cycle <NUM> (e.g., Δt<NUM> + Δt<NUM> + Δt<NUM>), and pavg.

In some embodiments, pavg is a weighted average based on an amount of time for which each particular psp was provided. For example, pavg may be determined using the equation: <MAT> or more generally: <MAT> where Δttotal is a total amount of time of the NPWT cycle, and n is a number of portions/sections of the NPWT cycle. This value of pavg may then be used by instillation volume manager <NUM> to determine or select the reduction factor θ.

In some embodiments, instillation volume manager <NUM> determines Vinstillation(k) for an upcoming fluid instillation cycle and provides Vinstillation(k) (also shown as V(k)) to control signal manager <NUM>. In some embodiments, instillation volume manager <NUM> also provides the value of Vinstillation(k) to instillation volume tracker <NUM> for use in determining future values of Vinstillation(k). In some embodiments, control signal manager <NUM> receives the value of Vinstillation(k) and determines control signals for pump <NUM> to deliver/provide the value of Vinstillation(k) to wound <NUM> for a fluid instillation cycle. In some embodiments, control signal manager <NUM> adjusts an operation of pump <NUM> and/or an instillation/fluid delivery pump to provide Vinstillation(k) instillation fluid to wound site <NUM>.

In some embodiments, instillation volume manager <NUM> provides user interface manager <NUM> with the value of Vinstillation(k). In some embodiments, user interface manager <NUM> determines display signals and provides the display signals to user interface <NUM>. In some embodiments, user interface manager <NUM> adjusts an operation of user interface <NUM> such that user interface <NUM> displays the value of Vinstillation(k) to a user. In some embodiments, this facilitates providing the user with an indication of how much instillation fluid to put in instillation fluid reservoir <NUM>. For example, in some embodiments, pump <NUM> is configured to deliver an entirety of instillation fluid present in instillation fluid reservoir <NUM> to wound site <NUM>. If user interface manager <NUM> causes user interface <NUM> to display Vinstillation(k), the user knows how much instillation fluid to provide to instillation fluid reservoir <NUM> for pump <NUM> to provide to wound site <NUM>.

In some embodiments, a user may replace foam <NUM> at dressing change stages. In some embodiments, user interface <NUM> is configured to receive a user input indicating that foam <NUM> has been replaced with fresh foam <NUM>. In some embodiments, user interface <NUM> is configured to provide user interface manager <NUM> with an indication of the changed foam <NUM>. In some embodiments, user interface manager <NUM> is configured to reset instillation volume manager <NUM> in response to a change of foam <NUM>. In some embodiments, wound volume manager <NUM> re-calculates an initial wound volume Vwound after foam <NUM> has been replaced. In some embodiments, user interface manager <NUM> causes user interface <NUM> to prompt a user to input wound volume Vwound at user interface <NUM>. In some embodiments, instillation volume manager <NUM> receives Vwound from at least one of wound volume manager <NUM> and user interface manager <NUM> and determines an initial instillation volume Vinstillation(k). Replacing foam <NUM> causes instillation volume manager <NUM> to "reset" such that instillation volume reductions calculated since the previous dressing change are no longer relevant, according to some embodiments. However, instillation volume manager <NUM> may still account for volume changes due to wound healing (e.g., changes in Vwound), but since foam <NUM> has been replaced, the changes in instillation fluid volume due to foam compression and clogging (e.g., reduced Cfoam) are no longer relevant. In some embodiments, instillation volume manager <NUM> essentially "re-starts" in response to foam <NUM> being replaced.

In some embodiments, instillation volume manager <NUM> accounts for a selected soak time of foam <NUM>. For example, allowing foam <NUM> to soak for a period of time after the delivery of instillation fluid but before the application of negative pressure can reduce the effect of compression set of foam <NUM>. In some embodiments, instillation volume manager <NUM> modifies (e.g., reduces) the reduction factor Θ based on the soak time Δtsoak. In some embodiments, instillation volume manager <NUM> determines an adjusted reduction factor θadj which accounts for the soak time Δtsoak. In some embodiments, instillation volume manager <NUM> uses the equation: <MAT> where Δθsoak is an adjustment amount determined based on Δtsoak (e.g., Δθsoak = f(Δtsoak)). In some embodiments, the longer foam <NUM> is allowed to soak, the greater Δθsoak is, and therefore the adjusted reduction factor θadj is decreased. In some embodiments, the soak time Δtsoak is defined as an amount of time after the instillation fluid has been provided to wound site <NUM> but before a negative pressure has been drawn at wound site <NUM>. In some embodiments, the soak time Δtsoak is input by a user via user interface <NUM>.

Referring now to <FIG>, graph <NUM> demonstrates the operation of controller <NUM> over time, according to some embodiments. Graph <NUM> illustrates several NPWT cycles, shown as NPWT cycle <NUM>, NPWT cycle <NUM>, and NPWT cycle <NUM>, according to some embodiments. There are fluid instillation cycles before NPWT cycle, shown as instillation cycle <NUM>, instillation cycle <NUM>, and instillation cycle <NUM>, according to some embodiments. NPWT cycle <NUM> is shown performed at <NUM> mmHg vacuum pressure for a time duration <NUM>, NPWT cycle <NUM> is shown performed at <NUM> mmHg vacuum pressure for a time duration <NUM>, and NPWT cycle <NUM> is shown performed at <NUM> mmHg vacuum pressure for a time duration <NUM>, according to some embodiments. In some embodiments, instillation fluid volume Vinstillation(k - <NUM>) was provided at instillation cycle <NUM>, Vinstillation(k - <NUM>) was provided at instillation cycle <NUM>, and Vinstillation(k - <NUM>) was provided at instillation cycle <NUM>. To determine Vinstillation(k) for a present instillation cycle <NUM>, controller <NUM> selects an appropriate reduction factor Θ from instillation reduction database <NUM> based on the vacuum pressure (i.e., <NUM> mmHg) of the previously performed NPWT cycle (i.e., NPWT cycle <NUM>), and a time duration of the previously performed NPWT cycle (i.e., time duration <NUM>), according to some embodiments. Controller <NUM> then determines Vinstillation(k) using the equation: <MAT> according to some embodiments. After instillation cycle <NUM> has been performed, Vinstillation(k) is then stored as Vinstillation(k - <NUM>) for future instillation cycles, according to some embodiments. Likewise, Vinstillation(k - <NUM>) for instillation cycle <NUM> was determined based on NPWT cycle <NUM> (i.e., time duration <NUM>, vacuum pressure <NUM> mmHg) and Vinstillation(k - <NUM>), Vinstillation(k - <NUM>) for instillation cycle <NUM> was determined based on NPWT cycle <NUM> (i.e., time duration <NUM>, vacuum pressure <NUM> mmHg), and Vinstillation(k - <NUM>), etc., according to some embodiments.

Referring now to FIG. <NUM>, graph <NUM> shows the change in instillation volume provided to a wound (e.g., wound <NUM>) over time, according to some embodiments. The Y-axis of graph <NUM> indicates a volume of instillation fluid provided to wound site <NUM> for a corresponding instillation cycle (the X-axis), according to some embodiments. As shown in graph <NUM>, since each volume of instillation fluid is determined based on a previous value of provided instillation fluid, the decrease over time is non-linear. In some embodiments, graph <NUM> may be linear if controller <NUM> decreases the instillation volume for each instillation cycle by a standard amount.

Referring now to <FIG>, a process <NUM> for determining an amount of instillation fluid to provide to a wound for NPWT is shown, according to some embodiments. In some embodiments, process <NUM> is performed by controller <NUM>. In some embodiments, process <NUM> is performed by one or more components of controller <NUM> (e.g., by instillation volume manager <NUM>).

Process <NUM> includes receiving a therapy pressure setpoint psp (step <NUM>), according to some embodiments. In some embodiments, the therapy pressure setpoint psp is a vacuum pressure setpoint for a NPWT cycle. In some embodiments, the therapy pressure setpoint psp is received by user interface manager <NUM>. In some embodiments, the therapy pressure setpoint is received by instillation volume manager <NUM>. In some embodiments, the therapy pressure setpoint is received by timer <NUM> for monitoring an amount of time NPWT is provided to the wound at the therapy pressure setpoint.

Process <NUM> includes instilling a wound area with a first instillation volume (step <NUM>), according to some embodiments. In some embodiments, step <NUM> includes determining an initial instillation volume as the first instillation volume. In some embodiments, the initial instillation volume is determined based on an estimated wound volume. In some embodiments, the estimated wound volume is provided to controller <NUM> via user interface <NUM>. In some embodiments, the wound volume is estimated by wound volume manager <NUM>. In some embodiments, instillation volume manager <NUM> is configured to receive the estimated wound volume to determine the initial instillation volume. In some embodiments, instillation volume manager <NUM> uses the wound volume and a relationship between wound volume and required instillation fluid to determine the initial instillation volume. In some embodiments, the relationship used by instillation volume manager <NUM> to determine the initial instillation volume is an empirical relationship. In some embodiments, control signal manager <NUM> receives the initial instillation volume from instillation volume manager <NUM> and adjusts an operation of pump <NUM> to provide wound site <NUM> with the initial volume of instillation fluid.

Process <NUM> includes monitoring an amount of elapsed NPWT time (step <NUM>), according to some embodiments. In some embodiments, the amount of elapsed time is monitored by timer <NUM>. In some embodiments, the amount of elapsed time is an amount of time for which NPWT has been performed at the therapy pressure setpoint as received in step <NUM>. In some embodiments, the monitored elapsed time is provided to instillation volume manager <NUM>.

Process <NUM> includes determining a second instillation volume and providing the second instillation volume of instillation fluid to the wound area (step <NUM>), according to some embodiments. In some embodiments, the new or adjusted instillation volume is decreased relative to the initial or first (i.e., previously provided) instillation volume. In some embodiments, the second instillation volume is determined based on a reduction factor Θ. In some embodiments, the reduction factor Θ is determined based on the therapy pressure setpoint, and the amount of elapsed time for which NPWT was provided at the therapy pressure setpoint. In some embodiments, step <NUM> is performed by instillation volume manager <NUM>. In some embodiments, step <NUM> includes any of the functionality of instillation volume manager <NUM> to determine Vinstillation(k).

Process <NUM> includes replacing the first instillation volume value with the second instillation volume value (step <NUM>), according to some embodiments. In some embodiments, the first instillation volume value is replaced by the second, most recently determined instillation volume value, in response to step <NUM> being completed. In some embodiments, step <NUM> is performed by instillation volume tracker <NUM>.

Process <NUM> includes repeating steps <NUM>-<NUM> until therapy is completed (step <NUM>), according to some embodiments. In some embodiments, step <NUM> is performed by controller <NUM>. In some embodiments, step <NUM>-<NUM> are repeated until NPWT is completed, or until a user changes dressings of the wound.

As utilized herein, the terms "approximately," "about," "substantially", and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

The hardware and data processing components used to implement the various processes, operations, illustrative logics, logical blocks, modules and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, particular processes and methods may be performed by circuitry that is specific to a given function. The memory (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. The memory may be or include volatile memory or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. According to an exemplary embodiment, the memory is communicably connected to the processor via a processing circuit and includes computer code for executing (e.g., by the processing circuit or the processor) the one or more processes described herein.

Claim 1:
A negative pressure wound therapy, NPWT, system (<NUM>) comprising:
an instillation system configured to provide instillation fluid to a wound site (<NUM>), wherein the wound site (<NUM>) comprises a wound and a wound dressing;
a controller (<NUM>) configured to:
provide a first quantity of instillation fluid for a first instillation cycle;
determine a second quantity of instillation fluid for a second instillation cycle based on the first quantity and a reduction factor, wherein the second quantity of instillation fluid is less than the first quantity of instillation fluid; and
adjust an operation of the instillation system to provide the second quantity of instillation fluid to the wound site (<NUM>),
characterized in that the reduction factor is determined based on a negative pressure of a negative pressure cycle and a time duration of the negative pressure cycle.