Patent Description:
<CIT> discloses a negative pressure apparatus which includes a negative pressure source configured to provide negative pressure via a fluid flow path to a wound dressing placed to create a seal over a wound, a pressure sensor, and a controller. The controller can be configured to operate the negative pressure source in a first mode and determine a change in pressure in the fluid flow path over a period of time based on a plurality of measurements by the pressure sensor. In response to a determination that pressure in the fluid flow path is decreasing, the controller can operate the negative pressure source in a second mode in which greater amount of negative pressure is provided than in the first mode. In response to a determination that pressure in the fluid flow path is not decreasing, the controller can provide an indication of a first leak in the seal.

<CIT> discloses a controller configured to monitor a duty cycle of a source of negative pressure in a negative pressure wound therapy apparatus. Based on the monitored duty cycle, the controller can determine whether a leak is present and provide an indication to a user. The controller can determine a duty cycle threshold in order to achieve an optimal or near optimal balance between an uninterrupted delivery of therapy, avoidance inconveniencing a user, conserving power, achieving optimal or near optimal efficiency, and/or limiting vibrational noise. In some embodiments, the duty cycle threshold is determined based at least in part on a capacity of a power source and an operational time of the apparatus.

One implementation of the present disclosure is a negative pressure wound therapy (NPWT) device. The NPWT device is configured to perform NPWT and includes a battery configured to supply the NPWT device with power, a pump configured to receive power from the battery and to produce a vacuum at a setpoint pressure to perform the NPWT, a user interface configured to provide alerts to a user, and a controller configured to receive power from the battery and to adjust the setpoint pressure of the pump, according to some embodiments. The controller is configured to operate the NPWT device in a standard therapy mode, a seal assist therapy mode, a pressure optimization mode, and a preservation mode of operation, according to some embodiments. The standard therapy mode includes operating the pump at a first setpoint vacuum pressure and periodically comparing a determined duty cycle value of the pump to a predetermined duty cycle threshold value, according to some embodiments. The seal assist therapy mode includes operating the pump at a second setpoint vacuum pressure, according to some embodiments. The second setpoint vacuum pressure is greater than the first setpoint vacuum pressure. The pressure optimization mode includes determining an initial pump duty cycle value and an initial battery capacity, reducing the setpoint pressure of the vacuum by a determined amount at an end of a timestep, determining a second pump duty cycle value at the end of the timestep, monitoring an actual vacuum pressure produced by the pump at the end of the timestep, and repeating the steps of reducing the setpoint pressure, calculating the second pump duty cycle value, and monitoring the actual vacuum pressure of the pump until the second pump duty cycle value is less than the predetermined duty cycle threshold value. The determined amount and the timestep are determined based on at least one of the initial pump duty cycle value and the initial battery capacity. The preservation mode of operation includes reducing the setpoint vacuum pressure to an absolute minimum pressure.

Referring generally to the FIGURES, a control algorithm for a NPWT device is shown, according to some embodiments. In some embodiments, the control algorithm includes a standard therapy pressure mode, a seal assist mode, a pressure optimization mode, and a preservation mode. The control algorithm switches the NPWT device between any of these modes based on various conditions, according to some embodiments. In some embodiments, the NPWT device is switched between these modes based at least one of a determination that a leak has occurred, a pump duty cycle value exceeding a threshold, and an energy/charge level of a power source. The control algorithm identifies leak events, and attempts to seal the leak by increasing setpoint pressure (seal assist mode), according to some embodiments. If the leak cannot be sealed with the seal assist mode, the NPWT device transitions into the pressure optimization mode where therapy is continued and the control algorithm attempts to provide as much negative pressure as possible given the constraints of the leakage amount and the energy/charge level of the power source. The control algorithm may adaptively increase or decrease the setpoint pressure to determine the optimal setpoint pressure, according to some embodiments. In some embodiments, the control algorithm increases or decreases the setpoint pressure linearly. In some embodiments, the control algorithm increases or decreases the setpoint pressure non-linearly based on time and/or pressure. Alternatively, the control algorithm may gradually reduce the pressure stepping to maintain higher therapy pressures for as long as possible while using lower target pressure/reduced pump duties to validate a duration of each pressure increment for gradually longer (as power consumption is reduced during each pressure lowering). In some embodiments, if the setpoint pressure cannot be maintained above a threshold value and/or if the energy/charge level of the power source drops below a threshold value, the control algorithm may transition the NPWT device into the preservation mode. The preservation mode provides an alert to a user (e.g., the patient) and attempts to provide a minimal amount of negative pressure, working on the basis that some negative pressure is better than none. Advantageously, the control algorithm allows a continuation of therapy despite a persistent dressing leak, reduces the need for the user to replace the power source (e.g., battery cells) early due to the persistent dressing leak, and provides fewer device alarms (e.g., low battery, leakage event, etc.). Additionally, the control algorithm conserves the energy/charge level of the power source (e.g., battery life) by reducing the setpoint pressure when a leak is detected and preventing the NPWT device from wasting the energy/charge of the power source.

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 to control an operation of pump <NUM> to perform a NPWT. 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> 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 has a limited energy capacity, and therefore optimization of the portable power source is advantageous, since when the portable power source runs out of energy, NPWT can no longer be performed.

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, 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 pressure setpoint 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> 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.

Referring now to <FIG>, a block diagram of controller <NUM> used in NPWT device <NUM> is shown, according to an exemplary embodiment. 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 transition NPWT device <NUM> between various modes of operation (e.g., standard therapy mode, seal assist mode, pressure optimization mode, preservation mode, etc.). 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>, memory <NUM> is shown to include power source capacity module <NUM>, according to some embodiments. In some embodiments, power source capacity module <NUM> is configured to receive information from power interface <NUM> regarding a remaining energy/charge of power source <NUM>. In some embodiments, power source capacity module <NUM> measures any of a supplied current from power source <NUM>, a voltage from power source <NUM>, and an amount of time power source <NUM> has provided power to controller <NUM>. Power source capacity module <NUM> may determine an amount of charge used over the amount of time power source <NUM> has provided power to controller <NUM>, according to some embodiments. In some embodiments, power capacity module <NUM> determines an amount of energy used over the amount of time. For example, power capacity module <NUM> may determine an amount of charge used over a time period (e.g., using Q = I * t), and determine a remaining amount of charge of power source <NUM> based on a difference between a total charge capacity of power source <NUM> and the amount of charge used over the time period. In response to determining the amount of charge remaining in power source <NUM>, power source capacity module <NUM> may determine a remaining amount of energy in power source <NUM> (e.g., by E = V * Q). In some embodiments, power capacity module <NUM> uses supplied voltage from power source <NUM> to determine a remaining amount of energy in power source <NUM>. Power capacity module <NUM> may receive an indication of remaining energy (or charge) in power source <NUM>, or may determine remaining energy (or charge) in power source <NUM>, according to some embodiments.

Referring still to <FIG>, power source capacity module <NUM> is shown providing mode transition module <NUM> with an indication of an amount of energy remaining in power source <NUM>, according to some embodiments. For example, power source capacity module <NUM> may provide mode transition module <NUM> with any of a charge remaining in power source <NUM>, an amount of energy (e.g., kW-hrs), and a percent of remaining energy and/or charge in power source <NUM>. Power source capacity module <NUM> provides mode transition module <NUM> with remaining energy level of power source <NUM> in a percentage (e.g., <NUM>% charge remaining, <NUM>% charge remaining, etc.), according to some embodiments. Mode transition module <NUM> uses the indication of energy/charge remaining in power source <NUM> to determine operational changes of NPWT device <NUM> and/or operational changes of pump <NUM>, according to some embodiments. In some embodiments, mode transition module <NUM> is configured to use the indication of remaining energy/charge in power source <NUM> to determine whether or not to transition NPWT device <NUM> and/or pump <NUM> between various modes of operation, described in greater detail below.

Referring still to <FIG>, controller <NUM> is shown to include input interface <NUM> and output interface <NUM>, according to some embodiments. Input interface <NUM> is configured to receive inputs from at least one of pump <NUM> and user interface <NUM>, according to some embodiments. In some embodiments, input interface <NUM> receives commands and/or requests from user interface <NUM>. For example, user interface <NUM> may receive a command from user 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, etc.). Input interface <NUM> is also configured to receive information from pump <NUM> regarding an actual therapy pressure, according to some embodiments.

Referring still to <FIG>, controller <NUM> is shown to include a pulse width modulation (PWM) module <NUM>, according to some embodiments. PWM module <NUM> receives a therapy pressure setpoint and performs PWM to adjust a duty cycle of pump <NUM> to achieve the therapy pressure setpoint, according to some embodiments. PWM module <NUM> is also shown receiving a feedback (i.e., actual therapy pressure) from pump <NUM> through input interface <NUM>, according to some embodiments. Pump <NUM> is configured to provide the therapy pressure to a wound, with a seal being placed between the wound and vacuum tubes used to apply the therapy pressure (e.g., negative pressure) to the wound. The vacuum tubes, wound, and any other vacuum elements used to provide the therapy pressure to the wound may be referred to as the vacuum system, according to some embodiments. The seal between the wound and the vacuum tubes may sometimes leak, causing PWM module <NUM> to increase the duty cycle of pump <NUM> to achieve the therapy pressure setpoint (i.e., actual therapy pressure = setpoint therapy pressure). In order to overcome pressure losses due to the leakage, pump <NUM> must operate at a higher pump duty cycle. In this way, a leak in the vacuum system is positively correlated to the duty cycle required to achieve the therapy pressure setpoint. Therefore, an unusually high pump duty cycle to achieve the therapy pressure setpoint may indicate a leak in the vacuum system, according to some embodiments. In this way, leaks may be identified and alerts may be provided to the user through user interface <NUM>, according to some embodiments. Additionally, the identification of leaks and the corresponding pump duty cycle may be used by mode transition module <NUM> to determine when to switch from one mode of operation to another mode of operation, according to some embodiments.

Referring still to <FIG>, controller <NUM> is shown to include duty cycle module <NUM>, according to some embodiments. Duty cycle module <NUM> is configured to communicate with PWM module <NUM> and monitor a current pump duty cycle of PWM module <NUM>, according to some embodiments. In some embodiments, duty cycle module <NUM> is configured to supply the monitored current pump duty cycle of PWM module <NUM> to mode transition module <NUM>. In some embodiments, duty cycle module <NUM> stores historical information of pump duty cycles used by PWM module <NUM> over a time period, and supplies this historical information to mode transition module <NUM>. For example, duty cycle module <NUM> may identify and store a maximum pump duty cycle and provide the maximum pump duty cycle to mode transition module <NUM>, according to some embodiments. In some embodiments, duty cycle module <NUM> may store a pump duty cycle threshold value and compare the monitored pump duty cycle value from PWM module <NUM> to the pump duty cycle threshold value. In some embodiments, the pump duty cycle threshold value is a predetermined value. In some embodiments, the pump duty cycle threshold value is determined based on at least one of a type of NPWT being performed (e.g., V. VERAFLO™ Therapy, PREVENA™ Therapy, ABTHERA™ Therapy, etc.) a type of NPWT device (e.g., various models of NPWT device <NUM>), a type of pump <NUM>, a rating of pump <NUM> (e.g., a particular pump may be rated for a maximum pump duty cycle), a duration of therapy time, an energy capacity of power source <NUM> (e.g., <NUM>% charge remaining, <NUM>% charge remaining, <NUM> kW-hrs remaining, etc.), a mode of operation of NPWT device <NUM> (e.g., standard therapy mode, seal assist mode, etc.), etc. If the pump duty cycle threshold value is determined rather than being a predetermined value, duty cycle module <NUM> may be configured to determine the pump duty cycle threshold value using any of an equation, a set of equations, a lookup table, a graph, a database, a script object, a function, etc. In some embodiments, duty cycle module <NUM> periodically receives/monitors pump duty cycle values from PWM module <NUM> at an end of a time step and periodically provides mode transition module <NUM> with the periodic pump duty cycle values. In some embodiments, duty cycle module <NUM> receives pump duty cycle values from PWM module <NUM> at an end of a time step having a predetermined duration (e.g., <NUM> second, <NUM> seconds, <NUM> minute, etc.).

In some embodiments, duty cycle module <NUM> is configured to calculate a continuous pump duty value. The continuous pump duty value ensures that the NPWT can be maintained for the prescribed therapy duration, according to some embodiments. Duty cycle module <NUM> is configured to calculate the continuous pump duty value based on any of a type of NPWT being performed (e.g., V. VERAFLO™ Therapy, PREVENA™ Therapy, ABTHERA™ Therapy, etc.) a type of NPWT device (e.g., various models of NPWT device <NUM>), a type of pump <NUM>, a rating of pump <NUM> (e.g., a particular pump may be rated for a maximum pump duty cycle), a duration of therapy time, an energy capacity of power source <NUM> (e.g., <NUM>% charge remaining, <NUM>% charge remaining, <NUM> kW-hrs remaining, etc.), a mode of operation of NPWT device <NUM> (e.g., standard therapy mode, seal assist mode, etc.), etc. Duty cycle module <NUM> may calculate the continuous pump duty value using any of an equation, a set of equations, a lookup table, a graph, a database, a script object, a function, etc. Duty cycle module <NUM> is configured to provide mode transition module <NUM> with the continuous pump duty value, according to some embodiments. In some embodiments, duty cycle module <NUM> calculates the continuous pump duty cycle value at a beginning of NPWT, while in some embodiments, duty cycle module <NUM> calculates the continuous pump duty cycle value periodically. In some embodiments, the periodically calculated continuous pump duty cycle value indicates a maximum pump duty cycle value which can be used to still perform the NPWT for the prescribed therapy duration, given current energy/charge level of power source <NUM>. In this way, duty cycle module <NUM> may provide information to mode transition module whether or not a current pump duty cycle value is tenable to complete the NPWT for the prescribed therapy duration given the current energy/charge capacity of power source <NUM>, according to some embodiments.

Referring still to <FIG>, controller <NUM> includes mode transition module <NUM>, according to some embodiments. Mode transition module <NUM> is configured to adjust a mode of operation of NPWT device <NUM>, according to some embodiments. In some embodiments, mode transition module <NUM> is configured to transition NPWT device <NUM> between various predetermined modes of operation. The various predetermined modes of operation are shown a standard therapy mode of operation, a seal assist mode of operation, a pressure optimization mode of operation and a preservation mode of operation. Each of standard therapy module <NUM>, seal assist module <NUM>, pressure optimization module <NUM>, and preservation mode module <NUM> are shown outputting therapy pressure setpoint values to PWM module <NUM>, according to some embodiments. In some embodiments, mode transition module <NUM> is configured to determine which of standard therapy module <NUM>, seal assist module <NUM>, pressure optimization module <NUM>, and preservation mode module <NUM> is allowed to output therapy pressure setpoints to PWM module <NUM> to adjust operation of NPWT device <NUM>. In some embodiments, standard therapy module <NUM> is configured to provide PWM module <NUM> with therapy pressure setpoints to operate according to the standard therapy mode of operation, seal assist module <NUM> is configured to provide PWM module <NUM> with therapy pressure setpoints to operate according to the seal assist mode of operation, pressure optimization module <NUM> is configured to provide PWM module <NUM> with therapy pressure setpoints to operate according to the pressure optimization mode of operation, and preservation mode module <NUM> is configured to provide PWM module <NUM> with therapy pressure setpoints to operate according to the preservation mode of operation. The functionality of each of these modes of operation is described in greater detail below with reference to <FIG>, according to some embodiments.

Mode transition module <NUM> is configured to transition NPWT device <NUM> between the above mentioned modes of operation, according to some embodiments. Mode transition module <NUM> is shown receiving input information from any of power source capacity module <NUM>, duty cycle module <NUM>, input interface <NUM>, and any of standard therapy module <NUM>, seal assist module <NUM>, pressure optimization module <NUM>, and preservation mode module <NUM>, according to some embodiments. In some embodiments, mode transition module <NUM> receives information from any of the above mentioned modules regarding energy/charge remaining in power source <NUM>, therapy pressure setpoint of pump <NUM>, actual therapy pressure of pump <NUM>, user inputs from user interface <NUM>, current pump duty cycle, historical pump duty cycle, continuous pump duty cycle, etc. In some embodiments, mode transition module <NUM> is configured to determine when to transition NPWT device <NUM> between any of the predefined modes of operation based on any of the information received as described hereinabove. The methods and functions of how mode transition module <NUM> determines when to transition NPWT device <NUM> between the predefined modes of operation is described in greater detail below with reference to <FIG>, according to some embodiments.

In some embodiments, mode transition module <NUM> is also configured to determine when to output an alarm to user interface <NUM>. In this way, mode transition module <NUM> may act as an alarm/alert module, according to some embodiments. In some embodiments, a separate alarm/alert module is used in conjunction with mode transition module <NUM> to determine when to output the alarm/alert to user interface <NUM>. Additionally, either of mode transition module <NUM> or the alarm/alert module may determine a type of alert/alarm to be displayed to the user via user interface <NUM>, according to some embodiments. For example, in some cases, either of mode transition module <NUM> and the alarm/alert module may determine that a visual alarm/alert should be provided to the user through user interface <NUM>, while in other cases both an auditory and a visual alert should be provided to the user through user interface <NUM>, according to some embodiments. In some embodiments, any of standard therapy module <NUM>, seal assist module <NUM>, pressure optimization module <NUM>, and preservation mode module <NUM> determine when to provide an alarm/alert to the user through user interface <NUM>, as well as the type of alert to be provided. Any of the modules described hereinabove which may be configured to determine if an alert should be provided, and the type of alert to be provided may determine alerts/alarms based on any of the information received by mode transition module <NUM> (e.g., energy/charge level of power source <NUM>, current pump duty cycle, etc.), according to some embodiments.

Referring now to <FIG>, an illustrative graph <NUM> of duty cycle resulting from PWM is shown, according to some embodiments. The illustrative graph <NUM> is shown to include a series <NUM> actuating between an on state and an off state, according to some embodiments. The y-axis of graph <NUM> represents the on state and the off state of a controlled equipment (e.g., pump <NUM>), and the x-axis of graph <NUM> represents time (e.g., time increasing), according to some embodiments. In some embodiments, series <NUM> is shown being in the on state for time interval <NUM>, and in the off state for time interval <NUM>. In some embodiments, time interval <NUM> is referred to as a pulse width PW. The summation of time interval <NUM> and time interval <NUM> is defined as period <NUM> (T), according to some embodiments. In some embodiments, the duty cycle is determined using a duty cycle equation, mathematically represented as <MAT>. In the duty cycle equation shown, D is the duty cycle (in terms of %), PW is time interval <NUM>, and T is period <NUM>, according to some embodiments. In this way, the duty cycle relates the on-time with the off-time, indicating an amount of time the controlled equipment has been in the on-state with respect to period <NUM>. When applied to pumps, duty cycle is a total amount of time the pump is in the on-state over an hour of operation, according to some embodiments. PWM module <NUM> is configured to modulate the pulse width PW (i.e., time interval <NUM>) to achieve various therapy pressure setpoints, according to some embodiments.

Referring now to <FIG>, control algorithm <NUM> is described in greater detail, according to some embodiments. Control algorithm <NUM> includes "increasing" or "decreasing" therapy pressure setpoint TPsetpoint, according to some embodiments. Since the present disclosure relates to NPWT, "increasing" the therapy pressure setpoint TPsetpoint means adjusting the therapy pressure setpoint TPsetpoint from a negative pressure value to a more negative pressure value (e.g., from -<NUM> mmHg to -<NUM> mmHg), according to some embodiments. Likewise, "decreasing" the therapy pressure setpoint TPsetpoint means adjusting the therapy pressure setpoint TPsetpoint from a negative pressure value to a less negative pressure value (e.g., from -<NUM> mmHg to -<NUM> mmHg), according to some embodiments. "Minimum" therapy pressure setpoint TPsetpoint means a least negative therapy pressure setpoint TPsetpoint value close to zero (e.g., -<NUM> mmHg), while a "maximum" therapy pressure setpoint TPsetpoint means a most negative therapy pressure setpoint TPsetpoint (e.g., -<NUM> mmHg), according to some embodiments. Similarly, "greater than" in regards to therapy pressure setpoint TPsetpoint means more negative (e.g., -<NUM> mmHg is greater than -<NUM> mmHg), and "less than" in regards to therapy pressure setpoint TPsetpoint means less negative (e.g., -<NUM> mmHg is less than -<NUM> mmHg), according to some embodiments. In any of <FIG>, "increasing" and "decreasing" may be taken to mean increasing or decreasing an absolute value of the therapy pressure setpoint TPsetpoint, according to some embodiments. Control algorithm <NUM> also includes increasing or decreasing the therapy pressure setpoint by certain amounts (e.g., Δp, Δpsmall, etc.), according to some embodiments. In some embodiments, the certain amounts are quantities, resulting in the therapy pressure setpoint TPsetpoint being linearly increased or decreased. In some embodiments, the amounts are functions of other variables (e.g., time, therapy pressure, pump duty cycle value, energy/charge level, etc.), resulting in the therapy pressure setpoint TPsetpoint being increased or decreased non-linearly.

Referring now to <FIG>, a block diagram of control algorithm <NUM> of NPWT device <NUM> is shown, according to some embodiments. In some embodiments, control algorithm <NUM> illustrates an overview of control algorithms described in greater detail below with reference to <FIG>.

The first step of control algorithm <NUM> is a startup step <NUM> and includes starting/initializing NPWT device <NUM>, according to some embodiments. NPWT device <NUM> may be started by connecting power source <NUM> to NPWT device <NUM> and receiving a command from a user to start the NPWT device <NUM>. In some embodiments, the user inputs the command to start NPWT device <NUM> through user interface <NUM>. In some embodiments, the user inputs the command to start NPWT device <NUM> through at least one of buttons <NUM>. The startup step <NUM> also includes setting various initial NPWT parameters (e.g., type of NPWT, duration of NPWT, therapy pressure setpoint of the NPWT, etc.), according to some embodiments. In some embodiments, the user determines the initial NPWT parameters through user interface <NUM>.

After NPWT device <NUM> has been started and initialized with various NPWT settings, NPWT device <NUM> enters a standard therapy mode of operation <NUM>, according to some embodiments. In some embodiments, the standard therapy mode of operation <NUM> corresponds to standard therapy module <NUM> determining therapy pressure setpoints. In some embodiments, the standard therapy mode of operation <NUM> includes setting the therapy pressure setpoint of pump <NUM> to a negative pressure (e.g., -<NUM> mmHg or any other negative pressure determined based on performance requirements), and periodically monitoring the pump duty cycle value of pump <NUM> to determine if a leak has occurred. If a leak does not occur, NPWT device <NUM> continues operating in standard therapy mode of operation <NUM> until the NPWT is completed, according to some embodiments. In some embodiments, standard therapy mode of operation <NUM> includes calculating the continuous pump duty cycle value as described in greater detail above with reference to <FIG>. In some embodiments, the continuous pump duty cycle value ensures that the NPWT can be maintained for the prescribed therapy duration.

If the pump duty cycle exceeds a predetermined threshold value, NPWT device <NUM> transitions out of the standard therapy mode of operation <NUM> and enters seal assist mode of operation <NUM>, according to some embodiments. In some embodiments, seal assist mode of operation <NUM> attempts to seal the leak in the vacuum system by increasing the therapy pressure setpoint over a time interval. In some embodiments, pump <NUM> can provide enough therapy pressure to overcome the leak and operate to perform the NPWT despite the leak, however, if a leak occurs, pump <NUM> may be required to operate at a higher pump duty cycle value, which may consume energy/charge from power source <NUM>. If the leak is sealed, NPWT device <NUM> may transition back into standard therapy mode of operation <NUM>, according to some embodiments. Seal assist mode of operation <NUM> includes ramping up the therapy pressure setpoint within safe limits (e.g., ramping up to -<NUM> mmHg) to attempt to seal the leak, and periodically checking the pump duty cycle to determine if the leak has been sealed (since, as described above, leakage correlates to pump duty cycle), according to some embodiments. If after a predetermined time period, the leak has been sealed (identified by the pump duty cycle returning to an expected value), NPWT device <NUM> transitions back into standard therapy mode of operation <NUM>, according to some embodiments.

If seal assist mode of operation <NUM> is unable to seal the leak (e.g., if the leak is too big, or if sealing the leak requires using an undesirable amount of energy/charge from power source <NUM>), NPWT device <NUM> transitions into therapy pressure optimization mode of operation <NUM>, according to some embodiments. Pressure optimization mode of operation <NUM> includes determining an efficient pump duty cycle value to provide therapy pressure at a different setpoint, such that the NPWT can be sufficiently performed given the energy/charge remaining in power source <NUM>, according to some embodiments. In some embodiments, pressure optimization mode of operation <NUM> includes optimizing therapy pressure setpoint based on pump duty cycle value and remaining energy/charge in power source <NUM>. In this way, therapy pressure optimization mode <NUM> allows NPWT device <NUM> to continue operating and administering NPWT despite leaks, according to some embodiments. Additionally, therapy pressure optimization mode of operation <NUM> may take into account remaining energy/charge in power source <NUM> and determine a therapy pressure setpoint and pump duty cycle which can be maintained for an entirety of the prescribed therapy duration. Advantageously, pressure optimization mode <NUM> continues the NPWT despite a leak or low energy/charge level of power source <NUM>. In this way, NPWT device <NUM> is prevented from merely outputting an alarm/alert to the user and shutting down, and provides a more versatile NPWT device which can operate to provide NPWT despite leaks and low energy/charge level. In some embodiments, if the pump duty cycle value exceeds a pump duty cycle threshold value and the energy/charge level of power source <NUM> is within a first range (e.g., <NUM>%-<NUM>%), the therapy pressure setpoint is incrementally lowered (e.g., reduced by <NUM> mmHg every <NUM> minutes) until the pump duty cycle value is below the pump duty cycle threshold value. This works on the principle that by lowering the therapy pressure, leak rate also lowers proportionally, according to some embodiments. When the energy/charge level of power source <NUM> is within the first range (e.g., <NUM>%-<NUM>%), NPWT device <NUM> has time to perform corrective measures to ensure therapy duration is maintained. If after an initial reduction in therapy pressure (e.g., an initial reduction of <NUM> mmHg), the pump duty cycle value is significantly lower than the pump duty cycle threshold value (e.g., <NUM>% lower, <NUM>% lower, etc.), therapy pressure may be gradually increased in smaller increments (e.g., <NUM> mmHg every <NUM> minutes) to maximize therapy pressure and balance against pump duty cycle, according to some embodiments.

If the energy/charge level of power source <NUM> is within a second range (e.g., <NUM>%-<NUM>%), therapy pressure setpoint may be incrementally reduced in larger increments or in a shorter time duration (e.g., reduced <NUM> mmHg every <NUM> minutes, or reduced <NUM> mmHg every <NUM> minutes, etc.) to speed up the optimization process of therapy pressure optimization mode of operation <NUM>, according to some embodiments. The increased rate at which the therapy pressure setpoint is reduced may result in larger deviations in the optimization process which may require additional steps of incrementally increasing the therapy pressure to fully optimize the therapy pressure setpoint with respect to the pump duty cycle value (e.g., leak rate), according to some embodiments.

If the energy/charge level of power source <NUM> is less than a lower bounds of the second range (e.g., below <NUM>%), therapy pressure setpoint is immediately reduced to a minimum allowable therapy pressure setpoint (e.g., -<NUM> mmHg) to conserve energy/charge remaining in power source <NUM> as much as possible and to attempt to maintain at least two hours of therapy duration to provide the user with sufficient time to arrange for the replacement of the power source <NUM> or to arrange for a new device to be fitted, according to some embodiments. If it is determined after the NPWT device <NUM> is at the minimum allowable therapy pressure setpoint that the NPWT device <NUM> can provide NPWT at a higher therapy pressure setpoint for two hours of therapy, the therapy pressure setpoint is incrementally increased until a therapy pressure setpoint is reached which can still be maintained for at least two hours.

If NPWT device <NUM> cannot provide NPWT at the minimum allowable therapy pressure setpoint and/or if energy/charge level of power source <NUM> decreases below a minimum threshold value, an alarm/alert is provided to the user through user interface <NUM> and NPWT device <NUM> transitions into preservation mode of operation <NUM>, according to some embodiments. Preservation mode of operation <NUM> includes lowering the therapy pressure setpoint to a new minimum value, working on the basis that some negative pressure is better than none. This principle works with absorbent dressing due to no head of fluid, according to some embodiments. For devices which exudate canisters, the new minimum value of the therapy pressure setpoint is determined based on tube length, according to some embodiments.

Referring now to <FIG>, a flowchart illustrating the control algorithm <NUM> described above with reference to <FIG> is shown in greater detail, according to some embodiments. Control algorithm <NUM> is shown to include standard therapy mode of operation <NUM>, seal assist mode of operation <NUM>, pressure optimization mode of operation <NUM>, and preservation mode of operation <NUM>, according to some embodiments. In some embodiments, standard therapy mode of operation <NUM> is standard therapy mode of operation <NUM>, seal assist mode of operation <NUM> is seal assist mode of operation <NUM>, therapy pressure optimization mode of operation <NUM> is therapy pressure optimization mode of operation <NUM>, and preservation mode of operation <NUM> is preservation mode of operation <NUM>, as described above with reference to <FIG>. In some embodiments, standard therapy mode of operation <NUM>/<NUM> is performed by standard therapy module <NUM>, seal assist mode of operation <NUM>/<NUM> is performed by seal assist module <NUM>, pressure optimization mode of operation <NUM>/<NUM> is performed by pressure optimization module <NUM>, and preservation mode of operation <NUM>/<NUM> is performed by preservation mode module <NUM> of controller <NUM>. In some embodiments, any of the methods or logic for transitioning between any of the various modes of operation is performed by mode transition module <NUM> of controller <NUM>.

The first step <NUM> of control algorithm <NUM> includes starting and initializing NPWT device <NUM>, according to some embodiments. In some embodiments, step <NUM> as shown in <FIG> is the same as step <NUM> shown in <FIG> and described in greater detail above with reference to <FIG>. After NPWT device <NUM> has been started and initialized, NPWT device <NUM> enters standard therapy mode of operation <NUM>, according to some embodiments.

The standard therapy mode of operation <NUM> first sets the therapy pressure setpoint, TPsetpoint, to an initial therapy pressure, pi, (step <NUM>) according to some embodiments. In some embodiments, the initial therapy pressure, pi, is -<NUM> mmHg. In some embodiments, the initial therapy pressure pi is an initial therapy therapy pressure. Standard therapy mode of operation <NUM> next compares the pump duty cycle value, PD, to a pump duty cycle threshold value, X, (step <NUM>) according to some embodiments. In some embodiments, if the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X, NPWT device <NUM> continues operating according to standard therapy mode of operation <NUM> (i.e., returns to step <NUM>).

If, however, the pump duty cycle value PD is greater than the pump duty cycle threshold value X, this indicates that a leak has occurred and NPWT device <NUM> transitions into seal assist mode of operation <NUM> to attempt to seal the leak, according to some embodiments. Seal assist mode of operation <NUM> first compares therapy pressure setpoint TPsetpoint to a new therapy pressure, pnew (step <NUM>), according to some embodiments. In some embodiments, the new therapy pressure pnew is greater than the initial therapy pressure pi. In some embodiments, the new therapy pressure pnew is -<NUM> mmHg. If the therapy pressure setpoint TPsetpoint is not equal to the new therapy pressure pnew, the therapy pressure setpoint TPsetpoint is set equal to the new therapy pressure pnew (step <NUM>), according to some embodiments. After the therapy pressure setpoint TPsetpoint is set equal to the new therapy pressure pnew, a timer is started (step <NUM>) for a predetermined amount of time t, according to some embodiments. In some embodiments, time t is <NUM> minutes. The pump duty cycle value PD is periodically compared to pump duty cycle threshold value X (e.g., periodically at an end of a time step such as every <NUM> second), according to some embodiments. If at any time the pump duty cycle value PD falls below or is equal to the pump duty cycle threshold value X, the NPWT device <NUM> is transitioned out of the seal assist mode of operation <NUM> and into the standard therapy mode of operation <NUM> (since the pump duty cycle value returning to an acceptable value indicates that the leak has been sealed) according to some embodiments. If, however, the pump duty cycle value PD does not fall below the pump duty cycle threshold value X (step <NUM>) and the timer is not greater than or equal to time t (step <NUM>), seal assist mode of operation <NUM> continues to periodically check both the pump duty cycle value PD (step <NUM>) and the therapy pressure setpoint TPsetpoint (step <NUM>), according to some embodiments. Once the timer reaches time t, the therapy pressure setpoint TPsetpoint is set to the initial therapy pressure pi (step <NUM> and step <NUM>), according to some embodiments. In some embodiments, NPWT device <NUM> is then allowed to operate at the initial therapy pressure for a predetermined amount of time. After the therapy pressure setpoint TPsetpoint is set to the initial therapy pressure pi, the pump duty cycle value PD is again compared to the pump cycle threshold value X (step <NUM>), according to some embodiments. If the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X, NPWT device <NUM> is transitioned from the seal assist mode of operation <NUM> into the standard therapy mode of operation <NUM> (since pump duty cycle value returning to an acceptable value indicates that the leak has been sealed), according to some embodiments. If the pump duty cycle value PD is greater than the pump duty cycle threshold value X, NPWT device <NUM> is transitioned from seal assist mode of operation <NUM> into pressure optimization mode of operation <NUM>, since this indicates that the leak has not and/or cannot be sealed with seal assist mode of operation <NUM>, according to some embodiments. In some embodiments, an actual therapy pressure TPactual is measured at the end of time t. If the actual therapy pressure TPactual does not equal pnew at the end of time t, NPWT device <NUM> is transitioned from seal assist mode of operation <NUM> into pressure optimization mode of operation <NUM>, according to some embodiments.

Referring now to <FIG>, pressure optimization mode of operation <NUM> of control algorithm <NUM> is shown, according to some embodiments. Pressure optimization mode of operation <NUM> first reduces the therapy pressure setpoint value TPsetpoint by a determined amount Δp (step <NUM>), according to some embodiments. In some embodiments, the value of Δp is determined based on energy/charge level of power source <NUM>, according to some embodiments. For example, if the energy/charge level of power source <NUM> is between a first range (e.g., <NUM>%-<NUM>%), Δp may equal <NUM> mmHg, according to some embodiments. If the energy/charge level of power source <NUM> is between a second range (e.g., <NUM>%-<NUM>%), Δp may equal <NUM> mmHg, according to some embodiments. In some embodiments, the value of Δp is inversely proportional to the energy/charge level of power source <NUM>, such that lower energy/charge levels of power source <NUM> correspond to a higher value of Δp. In this way, pressure optimization mode of operation <NUM> reduces TPsetpoint in larger increments if the energy/charge level of power source <NUM> is low, according to some embodiments. Pressure optimization mode of operation <NUM> next checks if the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>), according to some embodiments. If the pump duty cycle value PD is greater than the pump duty cycle threshold value X (step <NUM>) and the therapy pressure setpoint TPsetpoint is greater than a minimum therapy pressure value pmin (step <NUM>), pressure optimization mode of operation <NUM> continues reducing the setpoint therapy pressure TPsetpoint by Δp, according to some embodiments. In some embodiments, the minimum therapy pressure is -<NUM> mmHg. Pressure optimization mode of operation <NUM> continues reducing the therapy pressure setpoint TPsetpoint by Δp until either the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>) or until the therapy pressure setpoint TPsetpoint is less than or equal to the minimum therapy pressure pmin (step <NUM>), according to some embodiments. In some embodiments, the therapy pressure setpoint TPsetpoint is repeatedly reduced by Δp at an end of a time step having a duration Δt. In some embodiments, the time step duration Δt is determined similarly to the determination of the value of Δp. For example, Δt may be determined based on energy/charge level of power source <NUM>, according to some embodiments. For example, if the energy/charge level of power source <NUM> is between the first range (e.g., <NUM>%-<NUM>%), Δt may equal <NUM> minutes, according to some embodiments. If the energy/charge level of power source <NUM> is between a second range (e.g., <NUM>%-<NUM>%), Δt may equal <NUM> minutes, according to some embodiments. In some embodiments, the value of Δt is proportional to the energy/charge level of power source <NUM>, such that lower energy/charge levels of power source <NUM> correspond to a lower value of Δt. In this way, pressure optimization mode of operation <NUM> reduces TPsetpoint more often (i.e., at lower Δt values) if the energy/charge level of power source <NUM> is low, according to some embodiments.

If at any point in time while pressure optimization mode of operation <NUM> is reducing TPsetpoint, the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>), pressure optimization mode of operation <NUM> maintains the current TPsetpoint value (step <NUM>), according to some embodiments. Pressure optimization mode of operation <NUM> then determines if the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>), according to some embodiments. If the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>), NPWT device <NUM> is transitioned from pressure optimization mode of operation <NUM> into standard therapy mode of operation <NUM>, according to some embodiments. If the pump duty cycle value PD is still greater than the pump duty cycle threshold value X (step <NUM>), pressure optimization mode of operation <NUM> returns to reducing the therapy pressure setpoint TPsetpoint (steps <NUM>-<NUM>), according to some embodiments.

If, while pressure optimization mode of operation <NUM> is reducing the therapy pressure setpoint TPsetpoint, the therapy pressure setpoint TPsetpoint falls below the minimum therapy pressure value pmin (step <NUM>), NPWT device <NUM> is transitioned from pressure optimization mode of operation <NUM> to preservation mode of operation <NUM>, according to some embodiments. The goal of pressure optimization mode of operation <NUM> is to determine a therapy pressure setpoint TPsetpoint which can be maintained at an acceptable pump duty cycle value, according to some embodiments. If however, pressure optimization mode of operation <NUM> causes the therapy pressure setpoint TPsetpoint to fall below the minimum therapy pressure pmin, NPWT device <NUM> is transitioned out of pressure optimization mode of operation <NUM> into preservation mode of operation <NUM>, according to some embodiments.

Additionally, if the energy/charge level of power source <NUM> is less than a lower bounds of the second range (e.g., less than <NUM>%), pressure optimization mode of operation <NUM> immediately reduces the therapy pressure setpoint TPsetpoint to the minimum therapy pressure pmin, according to some embodiments.

Referring now to <FIG>, preservation mode of operation <NUM> of control algorithm <NUM> is shown, according to some embodiments. When NPWT device <NUM> is transitioned into preservation mode of operation <NUM>, a leak alert is provided to the user through user interface <NUM> (step <NUM>), according to some embodiments. In some embodiments, the leak alert is at least one of an auditory alert and a visual alert. Preservation mode of operation <NUM> next sets the therapy pressure setpoint TPsetpoint equal to the minimum therapy pressure pmin (step <NUM>), according to some embodiments. Preservation mode of operation <NUM> next checks if the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>), according to some embodiments. If the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>), preservation mode of operation <NUM> maintains the current therapy pressure setpoint TPsetpoint, according to some embodiments. In some embodiments, preservation mode of operation <NUM> maintains the current therapy pressure setpoint TPsetpoint for a predetermined amount of time (step <NUM>). If, after the predetermined amount of time, the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>) and the current setpoint therapy pressure TPsetpoint is maintained, NPWT device <NUM> is transitioned from preservation mode of operation <NUM> into standard therapy mode of operation <NUM>, according to some embodiments. In some embodiments, NPWT device <NUM> is only transitioned from preservation mode of operation <NUM> into standard therapy mode of operation <NUM> if the energy/charge level of power source <NUM> exceeds a predetermined threshold value (e.g., is above <NUM>%, is above <NUM>%, etc.).

If the pump duty cycle value PD is greater than the pump duty cycle threshold value X (step <NUM>), and the setpoint therapy pressure TPsetpoint does not equal a new minimum therapy pressure pmin,new (step <NUM>), the therapy pressure setpoint TPsetpoint is reduced by amount Δp, according to some embodiments. In some embodiments, the new minimum therapy pressure pmin,new equals -<NUM> mmHg. In some embodiments Δp is <NUM> mmHg. Preservation mode of operation <NUM> repeatedly reduces the therapy pressure setpoint TPsetpoint by the new amount Δpnew until either the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X or until the therapy pressure setpoint TPsetpoint equals the new minimum therapy pressure pmin,new, according to some embodiments. Once the therapy pressure setpoint TPsetpoint substantially equals the new minimum therapy pressure pmin,new (step <NUM>), intermittent therapy is applied at the new minimum therapy pressure pmin,new (step <NUM>), according to some embodiments. In some embodiments, the intermittent therapy is applied at a pump duty cycle value of <NUM>%. For example, the intermittent therapy may be repeatedly applied at the therapy pressure setpoint TPsetpoint equaling the new minimum therapy pressure pmin,new for five minutes on, and five minutes off, according to some embodiments.

If at any point in time when preservation mode of operation <NUM> is reducing the therapy pressure setpoint TPsetpoint by Δp (steps <NUM>-<NUM>), the pump duty cycle value PD is less than the pump duty cycle threshold value X (step <NUM>), preservation mode of operation <NUM> maintains the current therapy pressure setpoint TPsetpoint (step <NUM>), according to some embodiments. In some embodiments, preservation mode of operation <NUM> maintains the current therapy pressure setpoint TPsetpoint for a predetermined amount of time (step <NUM>). If, after the predetermined amount of time, the pump duty cycle value PD is less than or equal to the pump duty cycle threshold value X (step <NUM>) and the current therapy pressure setpoint TPsetpoint is maintained, NPWT device <NUM> is transitioned from preservation mode of operation <NUM> into standard therapy mode of operation <NUM>, according to some embodiments. In some embodiments, NPWT device <NUM> is only transitioned from preservation mode of operation <NUM> into standard therapy mode of operation <NUM> if the energy/charge level of power source <NUM> exceeds a predetermined threshold value (e.g., is above <NUM>%, is above <NUM>%, etc.). If after the predetermined amount of time, however, the pump duty cycle value PD is greater than the pump duty cycle threshold value X (step <NUM>), preservation mode of operation <NUM> resumes reducing the therapy pressure setpoint TPsetpoint by Δp (steps <NUM>-<NUM>), according to some embodiments.

Referring now to <FIG>, alternative pressure optimization mode of operation <NUM> and preservation mode of operation <NUM> of control algorithm <NUM> are shown, according to some embodiments. Pressure optimization mode of operation <NUM> as shown in <FIG> includes steps <NUM>-<NUM>, according to some embodiments.

Referring to <FIG>, pressure optimization mode of operation <NUM> first reduces the therapy pressure setpoint value TPsetpoint by a determined amount Δp (step <NUM>), according to some embodiments. In some embodiments, the value of Δp is determined based on energy/charge level of power source <NUM>, according to some embodiments. For example, if the energy/charge level of power source <NUM> is between a first range (e.g., <NUM>%-<NUM>%), Δp may equal <NUM> mmHg, according to some embodiments. If the energy/charge level of power source <NUM> is between a second range (e.g., <NUM>%-<NUM>%), Δp may equal <NUM> mmHg, according to some embodiments. In some embodiments, the value of Δp is inversely proportional to the energy/charge level of power source <NUM>, such that lower energy/charge levels of power source <NUM> correspond to a higher value of Δp. In this way, pressure optimization mode of operation <NUM> reduces TPsetpoint in larger increments if the energy/charge level of power source <NUM> is low, according to some embodiments. Pressure optimization mode of operation <NUM> next checks if the pump duty cycle value PD is greater than or equal to the pump duty cycle threshold value X (step <NUM>), according to some embodiments. If the pump duty cycle value PD is greater than the pump duty cycle threshold value X (step <NUM>) and the therapy pressure setpoint TPsetpoint is greater than a minimum therapy pressure value pmin (step <NUM>), pressure optimization mode of operation <NUM> continues reducing the therapy pressure setpoint TPsetpoint by Δp, according to some embodiments. In some embodiments, the minimum therapy pressure is -<NUM> mmHg. In some embodiments, the minimum therapy pressure is -<NUM> mmHg. Pressure optimization mode of operation <NUM> continues reducing the therapy pressure setpoint TPsetpoint by Δp until either the pump duty cycle value PD is less than the pump duty cycle threshold value X (step <NUM>) or until the therapy pressure setpoint TPsetpoint is less than the minimum therapy pressure pmin (step <NUM>), according to some embodiments.

If the pump duty cycle value PD is less than the pump duty cycle threshold value X (step <NUM>), pressure optimization mode of operation <NUM> checks if the pump duty cycle value PD is less than or equal to a second pump duty cycle threshold value Y, according to some embodiments. If the pump duty cycle value PD is less than the second pump duty cycle threshold value Y, pressure optimization mode of operation <NUM> increases the setpoint therapy pressure setpoint TPsetpoint by Δpsmall (step <NUM>), according to some embodiments. In some embodiments, Δpsmall is <NUM> mmHg. Next, the therapy pressure setpoint TPsetpoint is compared to the initial therapy pressure pi (step <NUM>), according to some embodiments. If the therapy pressure setpoint TPsetpoint does not equal the initial therapy pressure pi, step <NUM>, step <NUM>, and step <NUM> are repeated (provided that the pump duty cycle value PD meets the criteria of step <NUM> and step <NUM>). In this way, the therapy pressure setpoint TPsetpoint is repeatedly increased by ΔPsmall (step <NUM>), provided that the pump duty cycle value PD meets the criteria of step <NUM> and step <NUM>, according to some embodiments. If the pump duty cycle value PD meets the criteria of step <NUM> and step <NUM>, and the therapy pressure setpoint TPsetpoint is increased until it equals the initial therapy pressure pi, NPWT device <NUM> is transitioned out of pressure optimization mode of operation <NUM> and into standard therapy mode of operation <NUM>, according to some embodiments. In some embodiments, NPWT device <NUM> is only transitioned out of pressure optimization mode of operation <NUM> and into standard therapy mode of operation <NUM> if energy/charge level of power source <NUM> exceeds a predetermined value (e.g., is greater than <NUM>%, is greater than <NUM>%, etc.). In this way, NPWT device <NUM> cannot be transitioned back into standard therapy mode of operation <NUM> if energy/charge level of power source <NUM> is not sufficient to provide NPWT according to standard therapy mode of operation <NUM> for the prescribed therapy duration.

Referring now to <FIG>, preservation mode of operation <NUM> performs steps <NUM>-<NUM> as described above in greater detail with reference to <FIG>, according to some embodiments. However, if the pump duty cycle value PD is less than the pump duty cycle threshold value X (step <NUM>), preservation mode of operation then determines if the pump duty cycle value PD is less than or equal to the second pump duty cycle threshold value Y (step <NUM>), according to some embodiments. If the pump duty cycle value PD is greater than the second pump duty cycle threshold value Y, preservation mode of operation <NUM> performs step <NUM>, according to some embodiments. If, however, the pump duty cycle value PD is less than or equal to the second pump duty cycle threshold value Y (step <NUM>), the therapy pressure setpoint TPsetpoint is increased by Δpsmall (step <NUM>), according to some embodiments. In some embodiments, Δpsmall is <NUM> mmHg. After the therapy pressure setpoint TPsetpoint is increased by Δpsmall, the therapy pressure setpoint TPsetpoint is compared to pi (step <NUM>), according to some embodiments. If the therapy pressure setpoint TPsetpoint is equal to pi, NPWT device <NUM> is transitioned back into standard therapy mode of operation <NUM>, according to some embodiments. If the therapy pressure setpoint TPsetpoint is not equal to pi, preservation mode of operation <NUM> returns to step <NUM>, according to some embodiments. In this way, preservation mode of operation <NUM> may gradually increase the therapy pressure setpoint TPsetpoint to attempt and provide as much negative pressure as possible.

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, device (<NUM>) configured to perform NPWT, the NPWT device (<NUM>) comprising:
a battery (<NUM>) configured to supply the NPWT device (<NUM>) with power;
a pump (<NUM>) configured to receive power from the battery (<NUM>) and to produce a vacuum at a setpoint pressure to perform the NPWT;
a user interface (<NUM>) configured to provide alerts to a user;
a controller (<NUM>) configured to receive power from the battery (<NUM>) and to adjust the setpoint pressure of the pump and further configured to:
operate the NPWT device (<NUM>) in a standard therapy mode, wherein the standard therapy mode comprises operating the pump (<NUM>) at a first setpoint vacuum pressure and periodically comparing a determined duty cycle value of the pump (<NUM>) to a predetermined duty cycle threshold value;
operate the NPWT device (<NUM>) in a seal assist therapy mode, wherein the seal assist therapy mode comprises operating the pump (<NUM>) at a second setpoint vacuum pressure, wherein the second setpoint vacuum pressure is greater than the first setpoint vacuum pressure;
characterized in that the controller (<NUM>) is configured to operate the NPWT device (<NUM>) in a pressure optimization mode, wherein the pressure optimization mode comprises:
determining an initial pump duty cycle value and an initial battery capacity;
reducing the setpoint pressure of the vacuum by a determined amount at an end of a timestep;
determining a second pump duty cycle value at the end of the timestep;
monitoring an actual vacuum pressure produced by the pump (<NUM>) at the end of the timestep;
repeating the steps of reducing the setpoint pressure, calculating the second pump duty cycle value, and monitoring the actual vacuum pressure of the pump (<NUM>) until the second pump duty cycle value is less than the predetermined duty cycle threshold value; and
wherein the determined amount and the timestep are determined based on at least one of the initial pump duty cycle value and the initial battery capacity; and
operate the NPWT device (<NUM>) in a preservation mode of operation, wherein the preservation mode of operation comprises reducing the setpoint vacuum pressure to an absolute minimum pressure.