Negative pressure wound therapy system with dynamic fluid delivery

Abstract

To provide an NPWT device which takes into account therapy duration and does not overfill the wound with instillation fluid.SOLUTION: An NPWT 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.SELECTED DRAWING: Figure 2

Description

Background Art

[0001] Cross - reference to related applications This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 844,291, filed on May 7, 2019, which is hereby incorporated by reference in its entirety.

[0002] The present disclosure generally relates to negative pressure wound therapy (NPWT) devices, and more particularly to control algorithms for NPWT devices. Some NPWT devices introduce a cleaning fluid into a wound before negative pressure is drawn into the wound. Unfortunately, many systems provide an excessive amount of infusion fluid to the wound or do not account for changes in the liquid volume of the wound over time. This results in frequent leaks and a decline in NPWT quality. There is a need for an NPWT device that does not over - fill the wound with infusion fluid, taking into account the treatment period.

Summary of the Invention

[0003] One implementation of the present disclosure is, according to some embodiments, a negative pressure wound therapy (NPWT) system. In some embodiments, the system includes an infusion system configured to provide an infusion fluid to a wound site and a controller. In some embodiments, the wound site includes a wound and a wound dressing. In some embodiments, the controller is configured to provide a first amount of infusion fluid for a first infusion cycle. In some embodiments, the controller is configured to determine a second amount of infusion fluid for a second infusion cycle based on the first amount and a reduction factor. In some embodiments, the second amount of infusion fluid is less than the first amount of infusion fluid. In some embodiments, the controller is configured to adjust the operation of the infusion system to provide the second amount of infusion fluid to the wound site.

[0004] In some embodiments, the reduction factor is determined based on the negative pressure of the negative pressure cycle and the duration of the negative pressure cycle.

[0005] In some embodiments, the reduction factor is determined based on the amount of compression of the wound dressing over a period of time.

[0006] In some embodiments, the wound dressing includes one or more foam pieces.

[0007] In some embodiments, the controller is configured to receive an initial volume value of the wound from a user interface and use the initial volume value of the wound to determine a first amount of infusion fluid.

[0008] In some embodiments, the controller is configured to determine a second amount of infusion fluid for a second infusion cycle by determining a reduction amount based on the reduction factor and the first amount.

[0009] In some embodiments, the second amount is the difference between the first amount and the first amount multiplied by the reduction factor.

[0010] In some embodiments, the reduction factor is a normalized value.

[0011] In some embodiments, the controller is configured to select a reduction factor from a database of reduction factors based on the negative pressure of the negative pressure cycle and the duration of the negative pressure cycle.

[0012] Another embodiment of the present disclosure is a NPWT device configured to provide a liquid to a wound and create a negative pressure in the wound for NPWT, according to some embodiments. In some embodiments, the NPWT device monitors the negative pressure in the wound and the amount of elapsed treatment time, selects a reduction factor based on the monitored negative pressure in the wound and the monitored amount of treatment time, determines a reduced value of the liquid volume to be provided to the wound based on the previous value of the liquid volume provided to the wound and the reduction factor, and includes a controller configured to cause the NPWT device to provide the wound with the reduced value of the liquid volume. In some embodiments, the reduced value of the liquid volume is less than the previous value of the liquid volume provided to the wound.

[0013] In some embodiments, the reduction factor is a percentage value.

[0014] In some embodiments, the reduced liquid volume is determined by reducing the previous liquid volume by a percentage value.

[0015] In some embodiments, when the negative pressure monitored at the wound is 70 - 80 mmHg and the elapsed amount of treatment time is a predetermined amount of time, the percentage value selected by the controller is 3 - 6 percent.

[0016] In some embodiments, when the negative pressure monitored at the wound is 145 - 155 mmHg and the elapsed amount of treatment time is a predetermined amount of time, the percentage value selected by the controller is 7 - 9 percent.

[0017] In some embodiments, when the negative pressure monitored at the wound is 195 - 205 mmHg and the elapsed amount of treatment time is a predetermined amount of time, the percentage value selected by the controller is 9 - 11 percent.

[0018] In some embodiments, the reduction factor is determined based on an empirical relationship between the amount of treatment time at the negative pressure value and the amount of compression of the wound dressing.

[0019] Another embodiment of the present disclosure relates to a method for regulating and providing a certain amount of infusion fluid to a wound site. In some embodiments, the method includes monitoring the amount of elapsed time of negative pressure wound therapy (NPWT), determining a reduction amount based on the set value of the negative pressure of NPWT and the amount of elapsed time of NPWT during the elapsed time, determining a reduced infusion fluid amount by reducing a pre - defined infusion amount by the reduction amount, and providing the reduced infusion amount of infusion fluid to the wound site via an infusion system.

[0020] In some embodiments, the reduction amount is determined based on the reduction rate and the previously provided infusion amount.

[0021] In some embodiments, the reduction rate is determined based on the amount of elapsed time and the negative pressure set value of NPWT during the elapsed time.

[0022] In some embodiments, the reduction rate is selected from a series of reduction rates based on the amount of elapsed time and the negative pressure set value of NPWT during the elapsed time.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0041] Overview In general, according to some embodiments, diagrams, systems, methods, and devices are shown for dynamically adjusting the amount of infusion fluid provided to a wound. Often, the wound volume can change due to the compressive permanent strain of the dressing / foam, tissue swelling, granulation tissue formation, and wound healing. This can result in a reduction in the amount of infusion fluid (e.g., saline) required as NPWT. Users often overfill the liquid infusion reservoir, thereby providing an excessive amount of liquid to the wound. This can potentially have an adverse effect on the healing process and can cause confusion if the infusion fluid leaks to the user. Due to these factors, when NPWT is performed, the amount of infusion fluid required decreases. The controller receives various user and sensor inputs regarding the type of NPWT being performed, the duration of the NPWT, the vacuum pressure of the NPWT, etc. The controller can determine or select a reduction factor based on the vacuum pressure of the NPWT and the duration of the NPWT. The controller can determine a reduced infusion volume for future liquid infusion cycles based on the reduction factor and the pre-provided volume of infusion fluid. Advantageously, the controller can adjust the amount or volume of infusion fluid provided to the wound over time to reduce the likelihood of leakage. The reduction factor can take into account the immersion time. The reduction factor can be selected from a table or determined using a function obtained from an empirical relationship.

[0042] NPWT device Referring now to FIG. 1, a front view of an NPWT device 100 according to an exemplary embodiment is shown. According to some embodiments, the NPWT device 100 includes a user interface 106, buttons 104, a housing 102, and a controller 110. In some embodiments, the controller 110 is configured to control an NPWT application system 200 to perform NPWT on a wound side 202. In some embodiments, the controller 110 is configured to control the operation of a pump 142 to perform NPWT on the wound side 202. The NPWT application system 200 may include, according to some embodiments, a pump 142, an infusion fluid reservoir 204, a removed liquid reservoir 206, and pipes 208 and 210 (see FIG. 2). In some embodiments, the NPWT device 100 is configured to control the operation of V.A.C. VERAFLO (trademark) Therapy, PREVENA (trademark) Therapy, ABTHERA (trademark) Open Abdomen Negative Pressure Therapy, or any other NPWT (e.g., the controller 110 is configured to adjust the operation of the pump 142 and / or the NPWT application system 200 to perform any of the NPWTs described herein). In some embodiments, the NPWT device 100 is configured to control the operation of any device necessary to perform any of the NPWTs described herein (e.g., pumps, vacuum systems, infusion systems, etc.). In some embodiments, the NPWT device 100 is a disposable NPWT device (dNPWT) and may have reusable / disposable components. In some embodiments, for example, the NPWT device 100 may be relatively lightweight (e.g., less than 5 pounds) and portable, and the patient can carry the NPWT device 100 while the NPWT device 100 still performs NPWT. Since the NPWT device 100 may be portable, the NPWT device 100 can draw power from a portable power source (e.g., a power supply 120, a battery, etc.). The portable power source may have a limited energy capacity.In addition, the power source 120 may be a main power source (e.g., a wall outlet).

[0043] According to some embodiments, the user interface 106 is configured to display either an alert / warning regarding at least one of the battery capacity, leakage, pump duty cycle / pump duty value, etc. of the NPWT device 100. In some embodiments, the user interface 106 is configured to provide either a visual warning or an audible warning. In some embodiments, the user interface 106 enables the user to adjust the NPWT operation performed by the NPWT device 100. For example, the user provides user input to the controller 110 via the user interface 106 to increase the treatment pressure setting value p sp of the pump 142, adjust the type of NPWT performed, adjust the parameters / operations of the NPWT performed, adjust the duration of the NPWT performed, pause the NPWT, start the NPWT, and transition the NPWT device 100 to an "exchange" mode (e.g., to enable changing the wound dressing). In some embodiments, the user interface 106 displays the availability of infusion fluid for the user to provide. In some embodiments, the user interface 106 receives an input of the wound volume from the user. In some embodiments, the user interface 106 is any one of a resistive touch screen interface, a surface acoustic wave touch screen interface, a capacitive touch screen interface, etc. configured to enable the user to control the NPWT device 100. In some embodiments, the user interface 106 is controlled by the button 104. In some embodiments, the button 104 is configured to control the user interface 106 and / or adjust the NPWT operation performed by the NPWT device 100.

[0044] According to some embodiments, the user interface 106 is also configured to display the operating state of the NPWT performed. For example, the user interface 106 may display the patient name, the name of the caregiver, the type of NPWT currently being performed by the NPWT device 100, the duration of the NPWT, the remaining time of the current NPWT, the vacuum pressure of the NPWT, etc., or any other information related to the NPWT of the NPWT device 100 and / or the operating state of the NPWT device 100. According to some embodiments, for example, the user interface 106 is configured to display the remaining battery life of the battery (e.g., the power supply 120 shown in FIG. 2), and / or the duty cycle of the system (e.g., the pump 142) configured to provide vacuum pressure to the wound. In some embodiments, the remaining battery life of the battery is the amount of remaining energy in the battery. In some embodiments, the remaining battery life of the battery is the amount of remaining time that the NPWT device 100 can sustain the NPWT device in the current operating state. In some embodiments, the user interface 106 is configured to be communicatively connected to the controller 110. In some embodiments, the user interface 106 provides a controller 110 having any user input (e.g., treatment pressure setting value, selected treatment type, etc.). In some embodiments, the controller 110 causes the user interface 106 to display operating parameters such as NPWT, alarms, alerts, requests, etc.

[0045] In some embodiments, the user interface 106 is a touch screen. For example, the user interface 106 may be any of a capacitive touch screen, a resistive touch screen, etc. In some embodiments, the user interface 106 is configured to receive user input via the touch screen and provide the user input to the controller 110.

[0046] NPWT Application System Referring now to FIG. 2, according to some embodiments, the NPWT application system 200 is shown in more detail. The NPWT application system 200, according to some embodiments, includes a pump 142, an infusion reservoir 204, a drainage reservoir 206, a return tube 210, and a supply tube 208. In some embodiments, the pump 142 is configured to draw negative pressure into the wound site 202 via the return tube 210. In some embodiments, the pump 142 draws negative pressure at a treatment pressure setpoint p sp at the wound site 202. In some embodiments, the NPWT application system 200 is configured to provide a certain amount of infusion fluid (e.g., saline, etc.) to the internal volume 222 of the wound site 202 or the wound 218 via the supply tube 208. In some embodiments, the NPWT application system 200 provides infusion fluid to the internal volume 222 of the wound 218 from the wound side 202 and / or the infusion reservoir 204 via the supply tube 208. In some embodiments, the infusion fluid is a sterile fluid that can be used for wounds that require irrigation to prevent infection or to reduce the amount of infection in the wound.

[0047] The supply tube 208 and the return tube 210 are configured to promote the flow of liquids, gases, solutions, etc. inside, and have an internal volume configured to maintain a negative pressure (for example, sufficient strength not to collapse while the negative pressure is being generated inside the internal volume). They can be any form of piping, medical tubing, flexible tubing, etc. In some embodiments, the supply tube 208 and the return tube 210 are connected at a first end to the pump 142, and / or the infusion fluid reservoir 204, and / or the waste fluid reservoir 206. For example, the supply tube 208 can be fluidly connected to the infusion fluid reservoir 204 to provide fresh infusion fluid to the wound site 202. Similarly, the return tube 210 can be fluidly connected to the waste fluid reservoir 206 to remove liquid from the wound site 202. In some embodiments, the NPWT application system 200 may supply fresh infusion fluid to the wound site 202 via the pump 142. In some embodiments, the pump 142 includes one or more pumps. For example, a separate pump may be provided to supply a positive pressure to push the infusion fluid into the wound site 202 via the supply tube 208. In some embodiments, the pump 142 provides a negative pressure to the wound site 202 via the return tube 210. In some embodiments, the negative pressure provided via the return tube 210 provides a negative pressure to the internal volume 250. In some embodiments, the negative pressure in the internal volume 250 generated by the pump 142 draws the infusion fluid from the infusion fluid reservoir 204. In some embodiments, the liquid regulating device is arranged in line with the supply tubing 208 such that a sufficient volume or sufficient volumetric flow rate of infusion fluid is provided to the wound site 202 via the supply tubing 208. In some embodiments, the NPWT application system 200 operates between an NPWT cycle and a liquid infusion cycle. For example, according to some embodiments, the pump 142 is shown in a state of receiving a control signal (for example, from the controller 110). In some embodiments, the pump 142 initiates a liquid infusion cycle and initiates a liquid infusion cycle provided from the infusion fluid reservoir 204 to the wound site 202 via the supply tubing 208. In some embodiments, the total volume of the infusion fluid in the infusion fluid reservoir 204 is provided to the wound site 202.In some embodiments, pump 142 automatically provides a specific amount of infusion fluid from infusion fluid reservoir 204 to wound site 202. For example, in some embodiments, infusion fluid reservoir 204 contains 500 mL of infusion fluid, but pump 142 operates to provide only 15 mL of infusion fluid to wound site 202. In some embodiments, pump 142 executes a liquid infusion cycle by providing infusion fluid to wound site 202. In some embodiments, in response to providing an amount X of infusion fluid to wound site 202 during the liquid infusion cycle, pump 142 transitions to the immersion mode of the immersion cycle, and the infusion fluid is immersed in wound site 202. In some embodiments, the immersion mode includes maintaining pump 142 in an operating state for a predetermined time to allow the infusion fluid to be sufficiently immersed in wound site 202. In some embodiments, in response to completion of the liquid infusion cycle and the immersion cycle (e.g., the immersion cycle may be optional), pump 142 draws a negative pressure through return tube 210 over a period Δt. sp to draw a negative pressure. In some embodiments, pump 142 draws a negative pressure at sp to draw a negative pressure and executes NPWT for the NPWT cycle. In some embodiments, during the NPWT process, pump 142 transitions between the liquid infusion cycle and the NPWT cycle, thereby supplying and removing infusion fluid to and from wound site 202.

[0048] Referring further to FIG. 2, the wound site 202 includes a wound 218, a seal 214, and a foam 216. In some embodiments, the seal 214 is configured to seal along the entire outer periphery of the wound 218. In some embodiments, the seal 214 is configured to seal along the wound perimeter surface 212 surrounding the wound 218. In some embodiments, the seal 214 includes an adhesive for maintaining and sealingly connecting the seal 214 to the wound perimeter surface 212. In some embodiments, the seal 214 is configured to seal along the surface of the patient surrounding the wound perimeter surface 212. In some embodiments, the seal 214 covers and seals substantially the entire surface that includes the wound 218 therein. In some embodiments, the seal 214 defines an internal volume 250. In some embodiments, the internal volume 250 is defined as any volume between the seal 214 and the surface covered by the seal 214. For example, the internal volume 250 may include an internal wound volume 222.

[0049] The supply tube 208 and the return tube 210 are configured to be sealingly connected to the seal 214, thereby being in fluid communication with the internal volume 250. In some embodiments, the return tube 210 provides a negative pressure generated in the internal volume 250 by the pump 142. In some embodiments, the return tube 210 facilitates the discharge of air, gas, or liquid within the internal volume 250. Similarly, the supply tube 208 is configured to supply an infusion fluid to the internal volume 250 according to some embodiments. In some embodiments, the supply tube 208 is liquid-tightly and sealingly connected to the internal volume 250. In some embodiments, the supply tube 208 and the return tube 210 are sealingly and fluidly connected to the internal volume 250 defined by the seal 214 via connectors 224 and 226, respectively.

[0050] Referring further to FIG. 2, the controller 216 is shown disposed within the internal volume 222 of the wound 218 according to some embodiments. In some embodiments, the foam 216 includes one or more foam pieces configured to substantially fill the internal volume 222 of the wound 218. In some embodiments, the foam 216 is configured to absorb the infusion fluid provided from the infusion fluid reservoir 204 via the supply tube 208. In some embodiments, the foam 216 is configured to prevent particulate matter (e.g., scar tissue, scab, etc.) from entering the return tube 210. In some embodiments, the foam 216 is GRANUFOAM™. The foam 216 includes an outer surface 234 according to some embodiments. In some embodiments, at least a portion of the outer surface 234 of the foam 216 is the wound surface 220 substantially adjacent to the wound 218. In some embodiments, the entire portion of the outer surface 234 of the foam 216 is the adjacent wound surface 220 of the wound 218. In some embodiments, the foam 216 facilitates providing the infusion fluid to the wound 218 (e.g., at the wound surface 220). In some embodiments, the outer surface 234 of the foam 216 is in contact with the wound surface 220 of the wound 218.

[0051] The foam 216 includes an edge 235 according to some embodiments. In some embodiments, the edge 235 is or defines the outer perimeter of the foam 216. Similarly, the wound 218 includes an edge 221 according to some embodiments. In some embodiments, the edge 221 of the wound is or defines the outer perimeter of the wound 218. In some embodiments, the wound 218 has a depth 232. In some embodiments, the outer perimeter of the wound 218 increases with the depth 232. For example, the outer perimeter of the wound 218 may be larger at the wound perimeter surface 212 than the outer perimeter of the wound 218 (e.g., the wound 218 may increase in overall size at various depths).

[0052] Wound and Foam Volume Changes Referring now to FIGS. 3 - 6, according to some embodiments, wound 218 and foam 216 are shown in more detail. As shown in FIG. 3, wound 218 has an overall width (or length) shown as distance 230, and foam 216 has an overall width (or length) shown as distance 228 according to some embodiments. In some embodiments, distance 228 of foam 216 is substantially equal to distance 230 of wound 218. In some embodiments, distance 228 of foam 216 is substantially equal to distance 230 of wound 218 at the start of NPWT. For example, foam 216 may be filled within internal volume 222 of wound 218 such that foam 216 substantially fills the entirety of internal volume 222 of wound 218. In some embodiments, foam 216 is compressible so that it can be filled within internal volume 222 of wound 218. In some embodiments, since foam 216 is compressible, during the process of NPWT, its shape, diameter, outer perimeter, length, area, volume, etc. can be changed.

[0053] In some embodiments, the required amount of infusion fluid V 注入 changes throughout the process of NPWT. For example, in some embodiments, internal volume 222 of wound 218 changes (e.g., decreases) due to swelling (i.e., edema) of the surrounding or wound tissue, healing (e.g., contraction as wound 218 heals), granulation within wound 218, and compression of foam 216. In some embodiments, any of the above - mentioned volume changes (e.g., granulation, healing, edema, compression, etc.) change the required amount of infusion fluid V. For example, in some embodiments, the required amount of infusion fluid V decreases over the course of NPWT. Other systems may over - fill internal volume 250 with infusion fluid, which can increase the likelihood of leakage, seal failure, and degradation of the quality of NPWT. Further, a seal leak may allow air to enter internal volume 250, which can degrade the healing process and reduce the efficiency of pump 142. Advantageously, controller 110 is configured to reduce the amount of infusion fluid provided to internal volume 250 in order to subsequently cause the liquid infusion cycle described in more detail below.

[0054] According to some embodiments, the compression of the foam 216 is a significant contributing factor to the change in the required amount of infusion fluid V 注入 In some embodiments, the foam 216 undergoes a compression set. In some embodiments, the compression set of the foam 216 is the most significant factor that changes over time with respect to the required amount of infusion fluid V 注入 In some embodiments, the compression of the foam 216 is predictable based on any of the amount of compression (e.g., the negative pressure p in the internal volume portion 250 sp ), the temperature applied to the foam 216 (e.g., the human body temperature of the wound 218, etc.), and time (e.g., the treatment time). In some embodiments, as the foam 216 decreases in volume, height, width, area, outer periphery, etc. (e.g., as the foam 216 compresses), the liquid volume (C 発泡体 ) of the foam 216 decreases. In some embodiments, similar to the compression set of the foam 216 (e.g., as the liquid volume C 発泡体 decreases), the required amount of infusion fluid V 注入 decreases.

[0055] In some embodiments, when the seal 214 is removed (e.g., during dressing change, during seal change, etc.), the foam 216 is exposed to atmospheric pressure and expands. In some embodiments, the foam 216 returns to its original height, width, volume, etc. in response to being exposed to atmospheric pressure. However, in some embodiments, the foam 216 may not be able to return to its original height, width, volume, etc. (e.g., may not be able to re-expand). In some embodiments, the foam 216 may not be able to return to its original height, width, volume, etc. as NPWT continues. For example, in some embodiments, the foam 216 does not re-expand to its original height due to the infusion fluid or air present within the foam 216 provided to the foam 216 over the course of a previous NPWT implementation (e.g., previous round of NPWT). Further, the foam 216 may accumulate tissue substances that can reduce the liquid volume of the foam 216. In some embodiments, as NPWT continues, the amount by which the foam 216 re-expands (e.g., the amount by which the foam 216 returns to its original size, volume, height, width, etc.) decreases. In some embodiments, when the foam 216 cannot re-expand, this affects the static volume taken by the foam 216 before it appears to expand due to the liquid being delivered. In some embodiments, the controller 110 is configured to adjust the required amount of infusion fluid V 注入 provided to the wound site 202 by the NPWT application system 200 in order to account for the amount by which the foam 216 compresses.

[0056] Referring now to FIGS. 3 and 4, according to some embodiments, the foam 216 is shown before and after compression. FIG. 3 may represent the foam 216 before receiving the infusion fluid. FIG. 4 represents, according to some embodiments, the foam 216 after being exposed to negative pressure and temperature (e.g., human body temperature). As shown in FIGS. 3-4, the foam 216 has a height 238 and the wound 218 has a height / depth 232. In some embodiments, the height 238 of the foam 216 is initially substantially equal to the height / depth 232 of the wound 218. In some embodiments, after the foam 216 is exposed to negative pressure and temperature (FIG. 4), over time (e.g., treatment time), the height 238 of the foam decreases. As shown in FIG. 4, according to some embodiments, the height 238 of the foam 216 is less than the height / depth 232 of the wound 218 after the foam 216 has been exposed to negative pressure and temperature for an amount of time. In some embodiments, the decrease in the height 238 of the foam 216 affects the necessary amount of infusion fluid V provided to the wound site 202 注入 is affected.

[0057] Referring now to FIGS. 3 - 6, the width 228 of the foam 216 can, in some embodiments, decrease in a similar manner to the decrease in the height 238 of the foam 216. In FIGS. 3 and 5, the foam 216 has a total width 228 that is substantially equal to the total width 230 of the wound 218, according to some embodiments. In some embodiments, FIGS. 3 and 5 show the foam 216 before the foam 216 is exposed to negative pressure and temperature for a period of time. In some embodiments, as shown in FIG. 5, the overall outer perimeter 235 of the foam 216 is initially substantially equal to the outer perimeter 221 of the wound 218. In some embodiments, after the foam 216 is exposed to negative pressure and temperature for a period of time, as shown in FIG. 6, the overall outer perimeter 235 of the foam 216 decreases. In some embodiments, the decrease in the outer perimeter 235 of the foam 216 is due to the decrease in the width 228 of the foam 216. As shown in FIG. 6, the outer perimeter 235 of the foam 216 decreases by an amount such that the outer perimeter 235 is offset from the outer perimeter 221 of the wound 218 by a distance 236. In some embodiments, the decrease in the height 238 and / or width 228 and / or outer perimeter 235 of the foam 216 affects the necessary amount of infusion fluid V 注入 to be provided to the wound site 202. In some embodiments, the decrease in the outer perimeter 221 of the height 238 and / or width 228 is related to the liquid volume C 発泡体 of the foam 216. For example, the height 238 and the outer perimeter 221 decrease due to the accumulation of wound tissue material within the foam 216 and can decrease the liquid volume C 発泡体 of the foam 216. In some embodiments, the change in the liquid volume C 発泡体 indicates the necessary change in the necessary amount of infusion fluid V 注入 for the wound 218.

[0058] Referring now to FIGS. 7-10, according to some embodiments, a change in the overall size of wound 218 is shown. In some embodiments, wound 218 may change in overall size due to any of swelling, edema, and healing. In some embodiments, a change in the overall size of wound 218 reduces the internal volume portion 222 of wound 218. In some embodiments, when the internal volume portion 222 of wound 218 changes (e.g., decreases), the required amount of infusion fluid V to be provided to wound site 202 注入 changes (e.g., decreases). In some embodiments, the internal volume portion 222 of wound 218 decreases due to granulation.

[0059] Referring now to FIG. 7, according to some embodiments, wound 218 is shown in more detail. In some embodiments, the initial state of wound 218 as shown in FIG. 7 is the state of wound 218 before NPWT is initiated. Wound 218 has an overall width 230 in the initial state according to some embodiments. In some embodiments, wound 218 has an overall height 232 in the initial state. As shown in FIG. 8, when NPWT is performed on wound 218, according to some embodiments, at least one of the overall width 230 and the overall height 232 of the wound decreases. In some embodiments, the decrease in the overall height 232 and the overall width 230 of wound 218 reduces the internal volume portion 222 of wound 218. In some embodiments, the decrease in the internal volume portion 222 of wound 218 reduces the required amount of infusion fluid V to be provided to wound site 202 via supply tube 208 注入 . In some embodiments, controller 110 is configured to predict and offset the required amount of infusion fluid V over time to account for the decrease in the volume 222 of wound 218 as wound 218 heals. The internal volume portion 222 of wound 218 may decrease or change for any of the reasons enumerated herein (e.g., healing, granulation tissue formation, swelling, edema, etc.) according to some embodiments. 注入

[0060] As shown in FIGS. 9-10, according to some embodiments, the outer peripheral portion 221 of the wound 218 can change as NPWT continues (e.g., due to edema, wound 218 granulation healing, tissue formation, swelling, etc.). In some embodiments, the outer peripheral portion 221 of the wound 218 decreases as NPWT continues due to any of the above factors. In some embodiments, as the outer peripheral portion 221 of the wound 218 decreases, the required amount of infusion fluid V of the wound 218 注入 decreases. In some embodiments, as the wound 218 changes, the foam 216 changes in size, shape, outer periphery, width, height, etc. (e.g., shrinks). For example, as shown in FIG. 10, according to some embodiments, the outer peripheral portion 221 of the wound 218 reduces the offset distance 237 with respect to the initial outer peripheral portion 221 of the wound 218. Similarly, according to some embodiments, the outer peripheral portion 235 of the foam 216 also decreases.

[0061] According to some embodiments, the controller 110 is configured to adjust the required amount of infusion fluid V provided to the wound site 202 in order to account for either the volume change of the wound 218 or the volume change of the foam 216. 注入 In some embodiments, the controller 110 uses an empirical relationship to determine the amount by which the required amount of infusion fluid V 注入 and / or the required amount of infusion fluid V 注入 is increased or decreased to account for the change in the volume of the wound 218 and / or the change in the volume of the foam 216. In some embodiments, the change in the volume of the foam 216 is due to the compression permanent strain of the foam 216 as described above. In some embodiments, the change in the volume of the wound 218 is due to any of edema, swelling, wound healing, granulation tissue formation, etc.

[0062] Empirical relationship Referring now to FIGS. 11-12, graphs 1100 and 1200 show, according to some embodiments, the change in the height of the foam 216 and the change in the volume of the wound 218. In some embodiments, using the empirical relationships shown in graphs 1100 and 1200, the controller 110 determines the required amount of infusion fluid V注入 Determine the factors that determine it. In some embodiments, the empirical relationships shown in graphs 1100 and 1200 are used to determine the amount of infusion fluid V of the required amount 注入 Determine the amount by which to increase or decrease it. In some embodiments, the amount of infusion fluid V of the required amount 注入 The amount of the factor by which to increase or decrease it is referred to as the reduction coefficient θ.

[0063] Referring now to FIG. 11, graph 1100 shows, according to some embodiments, the change in height 238 of foam 216 with respect to treatment time (X-axis). In some embodiments, graph 1100 includes scatter data 1102. In some embodiments, scatter data 1102 is empirical data determined through testing. In some embodiments, for example, scatter data 1102 is determined by measuring an initial value of height 238 of foam 216 performing NPWT and measuring the value of height 238 of foam 216 after NPWT has been performed. For example, a single piece of foam 216 having an initial height 238 value of 30 mm may, according to some embodiments, be exposed to physiological saline (e.g., infusion fluid) at a negative pressure of 125 mmHg (e.g., p sp ) and a temperature of 35 degrees Celsius (approximately human body temperature) for a predetermined time (e.g., 24 hours). After a predetermined amount of time has elapsed, according to some embodiments, another value of height 238 of foam 216 (e.g., the value of height 238 of foam 216 is 29 mm). This process is repeated to obtain a specific set of temperatures and pressures (p sp)Regarding the conditions, data points relating the height 238 of the foam 216 to the treatment time can be determined (e.g., to determine data point 1102). For example, in some embodiments, a foam having an initial height 238 of 30 mm was exposed to the same conditions for another 12 hours, and the final value of the height 238 was recorded as 28 mm. Thus, according to some embodiments, when tested at 125 mmHg and 35 degrees Celsius, for the foam 216, h = 30 mm at t = 0 hours, h = 29 mm at t = 24 hours, and h = 28 mm at t = 36 hours, where h is the height 238 of the foam 216. This test may be continued, according to some embodiments, to determine some additional data points for various combinations of temperature and pressure. For example, this test may be performed, according to some embodiments, for negative pressures p such as 75 mmHg, 152 mmHg, 200 mmHg, etc. sp or may be performed for any other p sp value typically used during NPWT.

[0064] Referring further to FIG. 11, according to some embodiments, the linear trend line 1106 or the non-linear relationship 1104 can be determined based on the scattered data 1102 determined using the above test procedure. In some embodiments, the linear trend line 1106 and / or the non-linear relationship 1104 can be determined for each set of scattered data obtained from various test parameters (e.g., various values of p sp , various temperature values, etc.). In some embodiments, the relationship between the change in height h (i.e., the height 238 of the foam 216) and the treatment time is as follows: Δh = f 発泡体 (T, Δt, p sp ) where f 発泡体 is the relationship between Δh and T, the relationship between Δt and p sp , T is the temperature to which the foam is exposed during the test, Δt is the elapsed amount of treatment time, and p sp is the pressure to which the foam is exposed during the test. In some embodiments, f 発泡体depends on various properties of the foam. In some embodiments, f 発泡体 is a linear relationship between Δt and Δh. In some embodiments, f 発泡体 is a non - linear relationship between Δt and Δh. In some embodiments, f 発泡体 is determined for each combination of T and p that can be used during NPWT. In some embodiments, multiple tests are performed for various sets of T and p sp , and multivariate regression is performed to determine f sp for Δh with respect to T, Δt, and p sp . 発泡体

[0065] In some embodiments, the change Δh in the height of the foam 216 due to NPWT is proportional to the liquid volume of the foam 216 (i.e., C 発泡体 ∝Δh). In some embodiments, as the height h of the foam 216 decreases, the liquid volume C 発泡体 also decreases. In some embodiments, as the liquid volume C 発泡体 decreases (e.g., due to compression set, tissue substances within the foam 216, etc.), the required amount of infusion fluid V 注入 also decreases. Thus, as the foam 216 changes over time during NPWT, according to some embodiments, the required amount of infusion fluid V 注入 also changes over time. The controller 110 is configured, according to some embodiments, to reduce the amount of infusion fluid V sp for subsequent liquid infusion cycles based on Δt and p 注入 .

[0066] Referring now to FIG. 12, the graph 1200 shows, according to some embodiments, the change (V 創傷 ​) is shown. In some embodiments, the internal volume 222 of the wound 218 directly correlates with the liquid volume of the wound 218 (e.g., the amount of infusion fluid that the wound 218 can accommodate). In some embodiments, the graph 1200 includes scatter data 1202. In some embodiments, the scatter data 1202 are the results of various tests. For example, the scatter data 1202 may represent values of the internal volume 222 of the wound 218 measured over the entire NPWT application according to some embodiments. In some embodiments, the scatter data 1202 are collected for various NPWT applications using various temperatures T (e.g., various human body temperatures) and various negative pressure settings p sp . In some embodiments, a linear trend line 1206 is fitted to the scatter data 1202 to determine the relationship between the internal volume 222 of the wound 218 and the treatment time. In some embodiments, a non-linear relationship 1204 is determined based on the scatter data 1202 to determine the non-linear relationship between the internal volume 222 of the wound 218 and the treatment time. In some embodiments, the trend line 1206 and / or the non-linear relationship 1204 are used to predict the amount by which the internal volume 222 of the wound 218 decreases when NPWT is performed. Advantageously, the controller 110 uses the predicted change in the internal volume 222 of the wound 218 to determine the change in the required amount of infusion fluid V 注入 .

[0067] In some embodiments, using any of the relationships described herein with reference to graphs 1100 and 1200, the controller 110 determines the (plural) coefficient θ used to adjust the required amount of infusion fluid V 注入 . In some embodiments, the controller 110 stores one or more values of various NPWT parameters (e.g., various p sp values, various T values, various combinations of p sp and T values, etc.) and uses one or more θ values to determine the adjusted amount of infusion fluid V 注入Determine. In some embodiments, the controller 110 uses a function to determine the coefficient θ based on various NPWT parameters. In some embodiments, the value of the coefficient θ is determined based on any of the relationships shown in graphs 1100 and 1200.

[0068] Controller configuration Referring now to FIG. 13, in some embodiments, the controller 110 is shown in more detail. The controller 110, according to some embodiments, determines the change in the required amount of infusion fluid V 注入 and is configured to ensure that no excess infusion fluid is provided to the wound site 202. In some embodiments, the controller 110 advantageously reduces the tendency for an excessive amount of infusion fluid (e.g., an aqueous saline solution) to be introduced into the wound site 202. Some systems may require the user to manually determine the amount of infusion fluid added to the wound site 202. Advantageously, according to some embodiments, the controller 110 is configured to automatically adjust the amount of infusion fluid introduced into the wound site 202 to prevent leakage and improve the quality of NPWT.

[0069] According to some embodiments, the controller 110 is configured to control the operation of the pump 142 to perform NWPT. In some embodiments, the controller 110 controls the pump 142 and / or the NPWT application system 200 to deliver the determined infusion volume V to the wound site 202 for the liquid infusion cycle 注入configured to provide. According to some embodiments, controller 110 is shown to include a processing circuit shown as processing circuit 112. The processing circuit 112 may be configured to perform some or all of the functions of the controller 110. The processing circuit 112 is shown to include a processor shown as processor 114. The processor 114 may be a general-purpose single-chip 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 gates or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor 114 may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. The processor 114 may also be implemented as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration of computing devices. In some embodiments, certain processes and methods may be performed by circuitry specific to a given function. The processing circuit 112 also includes a memory shown as memory 116. The memory 116 (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, flash memory, hard disk storage device) for storing data and / or computer code for performing or facilitating the various processes, layers, and modules described in this disclosure.Memory 116 may be or may include a volatile memory or a 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, memory 116 is communicatively connected to processor 114 via processing circuit 112 and includes computer code for performing one or more processes described herein (e.g., by a processing circuit or a processor).

[0070] Continuing to refer to FIG. 13, according to an exemplary embodiment, the controller 110 is shown to include a power interface shown as power interface 134. According to some embodiments, the power interface 134 is configured to draw power supplied by a power source shown as power source 120 and supply power to the controller 110. In some embodiments, the power source 120 is any kind of permanent power source and / or temporary power source. In some embodiments, the power source 120 is a battery. In some embodiments, the power interface 134 is a connection port for a permanent power source (e.g., AC power and / or DC power) such as a connected 24VAC connection. In other embodiments, the power interface 134 includes both a port for permanent power and / or a power circuit configured to receive and convert power from the power source 120. In some embodiments, the power interface 134 is configured to receive power from both a permanent power source (e.g., an outlet) and a temporary power source (e.g., a battery). According to some embodiments, the power interface 134 may include any number of electrical components such as resistors, transistors, capacitors, inductors, diodes, transformers, transistors, switches, etc. that are necessary to receive, convert, and supply power to the controller 110. In some embodiments, when the power interface 134 is configured to receive power from a temporary power source (e.g., when the power source 120 is a battery), the power interface 134 may output power level data of the power source 120 to the processing circuit 112. The power level data can indicate the amount of remaining energy in the power source 120 (e.g., the number of remaining kWh in the power source 120). In some embodiments, the power source 120 is a replaceable power source (e.g., a battery). In some embodiments, the power source 120 is one or more disposable batteries. According to some embodiments, for example, the power source 120 is one or more disposable 12-volt batteries. In some embodiments, the power source 120 is one or more rechargeable batteries.In some embodiments, power supply 120 is configured to be temporarily disconnected from power interface 134 when a replaceable power supply must be replaced (e.g., if power supply 120 is one or more replaceable batteries, power supply 120 can be disconnected when the battery level is low and the battery must be replaced).

[0071] Continuing to refer to FIG. 13, according to some embodiments, the controller 110 is shown to include a communication interface 132. The communication interface 132 is configured to facilitate communication between the controller 110 and various external devices, sensors, systems, etc. According to some embodiments, the communication interface 132 is configured to receive inputs from at least one of the pump 142, the user interface 106, sensors, devices, etc. In some embodiments, the communication interface 132 receives commands and / or requests from the user interface 106. For example, the user interface manager 128 may receive a command from the user interface 106 via the communication interface 132 to transition the NPWT device 100 between various operating modes, or to adjust the operating characteristics of the NPWT being performed by the NPWT device 100 (e.g., increase the pressure setpoint, increase the amount of treatment time, etc.). According to some embodiments, the communication interface 132 is also configured to receive information regarding the actual treatment pressure or pump duty from the pump 142. In some embodiments, the communication interface 132 is configured to facilitate communication between the user interface 106 and the user interface manager 128. The communication interface 132 may include any wired or wireless interface. For example, according to some embodiments, the communication interface 132 may include a universal serial bus interface. In other embodiments, the communication interface 132 includes one or more wireless transceivers configured to wirelessly communicatively connect the controller 110 to various external devices, systems, sensors, etc. (e.g., the user interface 106 and the pump 142). In some embodiments, the communication interface 132 is configured to facilitate communication between the control signal manager 130 and the pump 142. For example, the control signal manager 130 may determine control signals for the pump 142 and / or the NPWT application system 200.In some embodiments, the communication interface 132 facilitates communication between the pump 142 and the control signal manager 130 such that the control signal manager 130 can output a control signal to the pump 142 to adjust the operation of the pump 142.

[0072] Continuing to refer to FIG. 13, according to some embodiments, it is shown that the memory 116 includes a user interface manager 128. In some embodiments, the user interface manager 128 is configured to receive one or more inputs from the user interface 106. In some embodiments, the user interface manager 128 is configured to receive one or more treatment parameters from the user interface 106 via the communication interface 132. One or two or more treatment parameters may be the type of treatment selected, the treatment pressure setting p sp , temperature (e.g., local temperature at the wound site 202), total treatment time t 合計 , and the volume V of the wound 218 創傷 . In some embodiments, the user interface manager 128 receives a treatment selection from the user interface 106 via the communication interface 132 and determines one or more of p sp , T, t 合計 , V 創傷 , etc. In some embodiments, the user interface manager 128 provides any of p sp , T, V 創傷 , and t 合計 to the infusion volume manager 124. In some embodiments, the infusion volume manager 124 uses any of these inputs, p sp , T, V 創傷 , and t 合計 to determine the infusion volume (i.e., volume) V 注入 . In some embodiments, T is assumed to be a normal human body temperature. In some embodiments, p spis the negative pressure set value input by the user via the user interface 106. In some embodiments, p sp is the negative pressure set value determined by the user interface manager 128 based on the type of treatment selected or received from the user interface 106.

[0073] Continuing to refer to FIG. 13, according to some embodiments, the memory 116 is shown to include a timer 118. In some embodiments, the timer 118 is configured to track the elapsed time during which NPWT is performed. For example, according to some embodiments, the timer 118 can record the start time and compare the start time of NPWT with the current time value to determine the total amount of time during which NPWT has been performed. In some embodiments, the timer 118 is configured to provide the total elapsed time to the infusion volume manager 124 and / or the wound volume manager 136. In some embodiments, the elapsed time is Δt. In some embodiments, the timer 118 maintains tracking of when the treatment is paused (e.g., the time for dressing change). In some embodiments, the timer 118 receives p sp from any of the user interface manager 128, the communication interface 132, etc. In some embodiments, when p sp changes (e.g., increases from 75 mmHg to 100 mmHg), the timer 118 records the time at which p sp changed. In some embodiments, the timer 118 tracks the amount of time during which NPWT was provided at a specific treatment pressure p sp . For example, if the NPWT device 100 provides NPWT at 100 mmHg over a first period and 125 mmHg over a second period, the timer 118, according to some embodiments, tracks the amount of time for the first and second periods. In some embodiments, the timer 118 is the previous pressure set value p spIt is configured to provide the elapsed time amount Δt from the change to the infusion volume manager 124. In some embodiments, the timer 118 identifies an event (e.g., treatment start time, change in pressure setting value p sp such as a change), and is configured to record the time amount Δt between continuously occurring events and / or the time amount elapsed from a previously occurred event Δt. The timer 118 may provide Δt to the infusion volume manager 124 and / or the wound volume manager 136.

[0074] Continuing to refer to FIG. 13, according to some embodiments, the memory 116 is shown to include a wound volume manager 136. In some embodiments, the wound volume manager 136 is configured to determine the volume 218V of the wound. 創傷 In some embodiments, the wound volume manager 136 is configured to provide the determined volume V of the wound 218 to the infusion volume manager 124. 創傷 In some embodiments, the wound volume manager 136 determines V based on any of the elapsed time Δt from the start of NPWT, the amount of elapsed time Δt from the change in the treatment pressure setting value p sp , the initial wound volume V 創傷、初期 , and empirical relationships. In some embodiments, V 創傷 is provided to the wound volume manager 136 via the user interface 106 and the communication interface 132 at the start of NPWT. For example, the user may measure the initial volume of the wound 218 and enter the initial volume of the wound 218 via the user interface 106. In some embodiments, the wound volume manager 136 uses the empirical relationships described in detail above with reference to FIG. 12 to determine the current volume of the wound 218. For example, the wound volume manager 136 can use the elapsed time from the start of NPWT, the pressure p 創傷、初期 at which NPWT is being performed, and the empirical relationship to determine the current value of V sp . In some embodiments, the wound volume manager 136 is V 創傷 In some embodiments, the wound volume manager 136 is V 創傷Determine the amount that has decreased over a certain period (e.g., since the start of NPWT). In some embodiments, the wound volume manager 136 provides V to the infusion volume manager 124. 創傷 is provided.

[0075] Continuing to refer to FIG. 13, according to some embodiments, the memory 116 is shown to include an infusion volume tracker 126. In some embodiments, the infusion volume tracker 126 is configured to record / track the infusion volume V over the previous cycle of NPWT. For example, according to some embodiments, the infusion volume tracker 126 may record the amount V of the infusion fluid provided to the wound site 202 during a previous liquid infusion cycle (e.g., liquid infusion cycle k-1). In some embodiments, the infusion volume tracker 126 records and tracks the amount of the infusion fluid (e.g., V 注入 ) provided to the wound 218 over the previous liquid infusion cycle. In some embodiments, the infusion volume tracker 126 receives the infusion volume amount V(k) determined by the infusion volume manager 124 for the current liquid infusion cycle (e.g., the current cycle of NPWT, the current liquid infusion cycle, etc.). For example, if the NPWT device 100 infuses X cubic centimeters of infusion fluid over an infusion fluid cycle and is then currently set to provide a 24-hour NPWT cycle at p = 100 mmHg, the infusion volume tracker 126 records the X cubic centimeters of infusion fluid infused in the first liquid infusion cycle. If the NPWT device 100 infuses the next X cubic centimeters of infusion fluid over a second infusion fluid cycle and then provides the NPWT at p = 125 mmHg for a second 24-hour NPWT cycle, the infusion volume tracker 126 adds the X cubic centimeters to the previously infused amount V of the infusion fluid. 注入 is configured to record / track the infusion volume V over the previous cycle of NPWT. For example, according to some embodiments, the infusion volume tracker 126 may record the amount V of the infusion fluid provided to the wound site 202 during a previous liquid infusion cycle (e.g., liquid infusion cycle k-1). 注入 is recorded. In some embodiments, the infusion volume tracker 126 records and tracks the amount of the infusion fluid (e.g., V 注入 ) provided to the wound 218 over the previous liquid infusion cycle. 注入 ) over the previous liquid infusion cycle. In some embodiments, the infusion volume tracker 126 receives the infusion volume amount V(k) determined by the infusion volume manager 124 for the current liquid infusion cycle (e.g., the current cycle of NPWT, the current liquid infusion cycle, etc.). 注入 (k). For example, if the NPWT device 100 infuses X cubic centimeters of infusion fluid over an infusion fluid cycle and then provides a 24-hour NPWT cycle at p 1 = 100 mmHg, the infusion volume tracker 126 records the X cubic centimeters of infusion fluid infused in the first liquid infusion cycle. If the NPWT device 100 infuses the next X cubic centimeters of infusion fluid over a second infusion fluid cycle and then provides the NPWT at p sp = 125 mmHg for a second 24-hour NPWT cycle, the infusion volume tracker 126 records the X cubic centimeters of infusion fluid infused in the second liquid infusion cycle. 1 cubic centimeters of infusion fluid. If the NPWT device 100 infuses the next X cubic centimeters of infusion fluid over a second infusion fluid cycle and then provides the NPWT at p 2 = 125 mmHg for a second 24-hour NPWT cycle, the infusion volume tracker 126 adds the X cubic centimeters to the previously infused amount V of the infusion fluid. sp = 125 mmHg, the infusion volume tracker 126 adds the X cubic centimeters to the previously infused amount V of the infusion fluid. 1 cubic centimeters to the previously infused amount V of the infusion fluid. 注入Can be provided to the infusion volume manager 124 as (k - 1), which is used by the infusion volume manager 124 to determine X for the second infusion cycle 2 Can be used. When the second 24 - hour NPWT cycle is completed, the infusion volume tracker 126 determines the amount of infusion fluid V previously infused as V(k - 1) as X 注入 as X 2 Can do, and can remember the infusion amount X from the first cycle as V(k - 2). Thus, the infusion volume tracker 126 records the infusion amounts of previously completed NPWT or liquid infusion cycles according to some embodiments. In some embodiments, the infusion volume tracker 126 also records the duration Δt of the previously executed NPWT cycle and the NPWT pressure setting value p(k - 1) of the previously executed NPWT cycle and provides these to the infusion volume manager 124 注入 from the first cycle as V(k - 2) and records the infusion amount X 1 as X sp Continuing to refer to FIG. 13, according to some embodiments, the memory 116 is shown to include the infusion volume manager 124. In some embodiments, the infusion volume manager 124 is configured to determine the amount of infusion fluid V to be provided to the wound site 202. In some embodiments, the infusion volume manager 124 is configured to determine V based on any one of the elapsed treatment time (e.g., Δt), the treatment pressure setting value p, the type of NPWT being performed, and the reduction factor θ. In some embodiments, the infusion volume manager 124 receives the reduction factor θ from the infusion reduction database 122. In some embodiments, the infusion reduction database 122 includes a look - up table of various values of θ for different combinations of T and p. In some embodiments, the various values of θ stored in the infusion reduction database 122 and provided to the infusion volume manager 124 are determined using empirical test results as described in more detail above

[0076] as V(k - 2) and records the infusion amount X 注入 as V sp as p 注入 as V sp as p

[0077] In some embodiments, the infusion volume manager 124 determines the amount (e.g., volume, quantity, etc.) V of infusion fluid to be provided to the wound 218 in the current infusion cycle k. 注入 (k). In some embodiments, for the first liquid infusion cycle, the infusion volume manager 124 determines that the first amount of infusion fluid is V determined by the wound volume manager 121 or received from the user interface manager 128. 創傷 For subsequent liquid infusion cycles, the infusion volume manager 124 determines the amount V of infusion fluid to be provided to the wound 218 in the current infusion cycle k based on the infusion fluid provided to the wound 218 in the previous liquid infusion cycle. 注入 (k). In some embodiments, the infusion volume manager 124 uses the following formula to determine the amount V of infusion fluid to be provided to the wound 218 in the current infusion cycle k. 注入 (k). V 注入 (k)=V 注入 (k - 1)-θ·V 注入 (k - 1) Wherein, V 注入 (k) is, according to some embodiments, the amount of infusion fluid (e.g., in cubic centimeters) to be provided to the wound 218 in the current liquid infusion cycle k, θ is the reduction coefficient, and V 注入 (k - 1) is the amount of infusion fluid (e.g., in cubic centimeters, mL, etc.) provided to the wound 218 in the previous liquid infusion cycle k - 1. In some embodiments, the term θ·V 注入 (k - 1) thereby represents the previously provided infusion fluid volume V 注入It is an amount for reducing the value of (k - 1). In some embodiments, the reduction coefficient θ is a normalized value (e.g., 0 to 1). In some embodiments, the reduction coefficient θ is a percentage value. In some embodiments, the reduction coefficient θ is selected by the infusion volume manager 124 from the infusion reduction database 122. In some embodiments, the reduction coefficient θ is selected or determined based on a previous NPWT cycle. In some embodiments, the reduction coefficient θ is based on the NPWT pressure setting value p sp , and p sp and is selected or determined based on both the amount of time Δt that NPWT was provided to the wound 218 at. In some embodiments, the reduction coefficient θ is determined using a function, θ = f reduc (Δt, p sp ) where θ is the reduction coefficient, p sp is the NPWT pressure setting value of the previous negative pressure cycle, Δt is the duration that NPWT was run at p sp in the previous NPWT cycle, and f reduc is the relationship between θ, p sp , and Δt. In some embodiments, f reduc is a function determined based on empirical data. In some embodiments, f reduc is determined based on the estimated change amount in V sp over the period Δt at the NPWT pressure setting value p 創傷 (e.g., due to changes in edema, swelling, healing of the foam 216, etc.).

[0078] In some embodiments, the reduction coefficient θ is selected from a table of values stored in the infusion reduction database 122. For example, the infusion reduction database 122 may include a table 1400 as shown in FIG. 14. Table 1400 includes a column 1402 representing the previously provided NPWT pressure setting value p sp , and the time when NPWT was at p spIncludes column 1406 of the provided duration Δt. Table 1400 includes column 1404 having values of a reduction coefficient θ according to some embodiments. In some embodiments, the infusion volume manager 124 is p sp Based on and Δt, the defined reduction database 122p sp Based on and Δt, searches the table 1400 stored in the infusion reduction database for an appropriate value of the reduction coefficient θ. For example, as shown in FIG. 14, when NPWT is provided to wound 218 at a pressure of p sp = 75 mmHg for Δt = 24 hours, the reduction coefficient θ is 0.05 (or a 5% reduction) according to some embodiments. In some embodiments, the infusion volume manager 124 receives the amount / volume of infusion fluid V 注入 (k - 1) from the infusion volume tracker 126. For example, according to some embodiments, 30 cm 3 of infusion fluid eye drops were provided to wound 218 in a previous liquid infusion cycle, and the reduction coefficient θ is 0.05 (e.g., p sp = 75 and Δt = 24 hours), the infusion volume manager 124 determines the volume of the infusion fluid for the current liquid infusion cycle as follows. V 注入 (k)=30 cm 3 -0.05·30 cm 3 =30 cm 3 -1.5 cm 3 =28.5 cm 3

[0079] In some embodiments, the infusion volume manager 124 receives the estimated / calculated current volume of wound 218 from the wound volume manager 121. In some embodiments, the infusion volume manager 124 receives the estimated / calculated current volume of wound 218 from the user interface manager 128. In some embodiments, the infusion volume manager 124 uses the estimated current volume of wound 218 to determine the reduction coefficient θ. In some embodiments, the infusion volume manager 124 uses the following function to determine the reduction coefficient θ based on the wound volume V 創傷 and θ = f reduc, V創傷 (V 創傷 (k),V 創傷 (k - 1)) wherein V 創傷 (k) is the estimated volume of the wound 218 received from the wound volume manager 121 or the user interface 106 in the current liquid injection cycle k, and V 創傷 (k - 1) is the previously estimated wound volume 218 in the previous liquid injection cycle, and f reduc,v創傷 is a function that associates θ with V 創傷 (k) and V 創傷 (k - 1).

[0080] In some embodiments, the NPWT cycle may include a change in p sp at various points in the NPWT cycle. Graph 1700 of FIG. 16 shows an NPWT cycle 1714 having multiple stages according to some embodiments. Graph 1700 shows the applied negative pressure p sp with respect to the elapsed time (X - axis) (Y - axis) according to some embodiments. In some embodiments, the NPWT cycle 1714 includes a first portion 1708, a second portion 1710, and a third portion 1712. According to some embodiments, the first portion 1708 has p sp = p 1 for a duration 1702 (i.e., Δt 1 ), the second portion 1710 has p sp = p 2 for a duration 1704 (i.e., Δt 2 ), and the third portion 1712 has p sp = p 3 for a duration 1706 (i.e., Δt 3 ). In some embodiments, p sp increases from the first portion 1708 to the second portion 1710 and decreases from the second portion 1710 to the third portion 1712. In some embodiments, the infusion volume manager 124 treats each of the portions 1708 - 1712 as individual portions by determining a reduction factor θ for each portion, and for the liquid injection cycle after the NPWT cycle 1714, V 注入Determine. In some embodiments, durations 1702-1706 are recorded by timer 118. In some embodiments, infusion volume manager 124 uses the following formula. TIFF2025081329000002.tif21170Where n is the number of sub - sections / sections of the NPWT cycle that occurred between infusion cycle k and infusion cycle k - 1 (e.g., 3 in the example shown in FIG. 16), and θ i is the reduction factor for each sub - section of the NPWT cycle (e.g., NPWT cycle 1714).

[0081] In NPWT cycle 1714, the above formula reduces to the following. V 注入 (k)=V 注入 (k - 1)-V 注入 (k - 1)(θ 1 +θ 2 +θ 3 ) Where θ 1 =f reduc (Δt 1 ,p 1 ), θ 2 =f reduc (Δt 2 ,p 2 ), and θ 3 =f reduc (Δt 3 ,p 3 ). The reduction factors θ 1 , θ 2 , and θ 3 each may be determined by using function f reduc or by selecting an appropriate reduction factor from infusion reduction database 122 based on Δt and p sp . The above formula reduces to the following according to some embodiments. TIFF2025081329000003.tif21170In some embodiments, n indicates the number of parts of the NPWT cycle between liquid infusion cycle k and liquid infusion cycle k - 1. In some embodiments, n is the pressure p of the NPWT specified by timer 118 spIt is determined based on the number of changes. In some embodiments, the infusion volume manager 124 determines the number of portions of the NPWT cycle as follows, n = #p sp Change + 1 where #p sp of change is the number of changes in p sp over the entire NPWT cycle. However, if the NPWT cycle is performed at a single pressure (e.g., p sp = 150 mmHg), the change in #p sp is zero and n is 1. In some embodiments, the number of portions of the NPWT cycle indicates the number of reduction factors θ.

[0082] In some embodiments, for an NPWT cycle having a plurality of sections (e.g., NPWT cycle 1714), the infusion volume manager 124 processes each portion / section as an individual NPWT cycle. For example, the infusion volume manager 124 may determine a reduction factor θ for each portion / section and determine an adjusted volume V 注入 of the infusion fluid for each portion / section. However, according to some embodiments, the previous infusion fluid volume V 注入 (k - 1) of the subsequently occurring portion / section is set equal to the infusion fluid V 注入 of the immediately preceding portion / section. For example, according to some embodiments, in NPWT cycle 1714, section 1708 has a reduction factor θ 1 , section 1710 has a reduction factor θ 1 , and section 1712 has a reduction factor θ 3 . In some embodiments, the infusion volume manager 124 uses the following formula, TIFF2025081329000004.tif21170where, according to some embodiments, n is the number of sections of the NPWT cycle due to a change in the pressure set value, V 注入 (k - 1) is the volume of infusion fluid supplied to the wound during the liquid infusion cycle before the NPWT cycle, V 注入(k) is the amount of infusion fluid to be provided to the wound during the liquid infusion cycle after the NPWT cycle.

[0083] For example, according to some embodiments, Δt 1 is 24 hours, and p 1 is 152 mmHg, Δt 2 is 24 hours, and p 2 is 200 mmHg, Δt 3 is 24 hours, and p 3 is 75 mmHg, then, as determined by referring to Table 1400, θ 1 = 0.08, θ 2 = 0.10, and θ 3 = 0.05. For the sake of example, according to some embodiments, assuming that the previously provided infusion volume V 注入 (k - 1) is 100 mL, the infusion volume to be provided to the liquid infusion cycle after the NPWT cycle 1714 can be determined as follows. V 注入 (k) = (V 注入 (k - 1))(1 - θ 1 )(1 - θ 2 )(1 - θ 3 ) = 100 mL(1 - 0.08)(1 - 0.10)(1 - 0.05) = 100 mL(0.7866) = 78.66 mL

[0084] Alternatively, the infusion fluid volume V 注入 (k) can be determined using the following formula. TIFF2025081329000005.tif21170 This, according to some embodiments, is as follows. V 注入 (k) = 100 mL(1 - (0.08 + 0.10 + 0.05)) = 100 mL(0.77) = 77 mL

[0085] In some embodiments, the pressure set value p spFor an NPWT cycle having multiple parts due to changes, the average pressure over the entire NPWT cycle is determined. For example, for the NPWT cycle 1714 shown in FIG. 16, the average setpoint p avg can be determined as follows, TIFF2025081329000006.tif15170which, according to some embodiments, can be generalized as follows. TIFF2025081329000007.tif15170

[0086] In some embodiments, for the injection volume V 容積 (k) for the liquid injection cycle after the NPWT cycle 1714, can then be determined, V 注入 (k)=(V 注入 (k - 1))(1 - θ avg ) where θ avg is a reduction factor selected or determined based on the total Δt (e.g., Δt 1 +Δt 2 +Δt 3 ) of the NPWT cycle 1714, and p avg .

[0087] In some embodiments, p avg is a weighted average based on the amount of time each particular p sp was provided. For example, p avg can be determined using the following equation, TIFF2025081329000008.tif15169or more generally, TIFF2025081329000009.tif21170where Δt 合計 is the total time of the NPWT cycle and n is a part / section of the NPWT cycle. Then, this value of p avg may be used by the injection volume manager 124 to determine or select the reduction factor θ.

[0088] In some embodiments, the infusion volume manager 124 determines V 注入 (k) for the next liquid infusion cycle and provides V 注入 (k) (also denoted as V(k)) to control the control signal manager 130. In some embodiments, the infusion volume manager 124 also provides the value of V 注入 (k) to the infusion volume tracker 126 for use in determining future values. In some embodiments, the control signal manager 130 receives the value of V 注入 (k) and determines a control signal for the pump 142 to deliver / provide the value of V 注入 (k) to the wound 218 for the liquid infusion cycle. In some embodiments, the control signal manager 130 adjusts the operation of the pump 142 and / or the infusion / liquid delivery pump to provide V 注入 (k) infusion fluid to the wound site 202. 注入 (k) infusion fluid to the wound site 202.

[0089] In some embodiments, the infusion volume manager 124 provides the value of V 注入 (k) to the user interface manager 128. In some embodiments, the user interface manager 128 determines a display signal and provides the display signal to the user interface 106. In some embodiments, the user interface manager 128 adjusts the operation of the user interface 106 such that the user interface 106 displays the value of V 注入 (k) to the user. In some embodiments, this facilitates providing the user with an indication of how much infusion fluid is disposed within the infusion fluid reservoir 204. For example, in some embodiments, the pump 142 is configured to deliver the entire infusion fluid present within the infusion fluid reservoir 204 to the wound site 202. When the user interface manager 128 causes the user interface 106 to display V 注入 (k), the user knows how much infusion fluid to provide to the infusion fluid reservoir 204 for the pump 142 to provide to the wound site 202.

[0090] In some embodiments, the user can replace the foam 216 during the dressing replacement phase. In some embodiments, the user interface 106 is configured to receive a user input indicating that the foam 216 has been replaced with a new foam 216. In some embodiments, the user interface 106 is configured to provide a display of the replaced foam 216 to the user interface manager 128. In some embodiments, the user interface manager 128 is configured to reset the infusion volume manager 124 in response to the replacement of the foam 216. In some embodiments, the wound volume manager 121 recalculates the initial wound volume V 創傷 after the foam 216 is replaced. In some embodiments, the user interface manager 128 prompts the user to enter the wound volume V 創傷 in the user interface 106. In some embodiments, the infusion volume manager 124 receives V 創傷 from at least one of the wound volume manager 121 and the user interface manager 128 and determines the initial infusion volume V 創傷 (k). According to some embodiments, replacing the foam 216 causes the infusion volume manager 124 to be "reset" so that a reduction in the infusion volume is calculated because the previous dressing replacement is no longer relevant. However, the infusion volume manager 124 may account for volume changes due to wound healing (e.g., changes in V 創傷 ), but since the foam 216 has been replaced, volume changes due to foam compression and clogging (e.g., reduced C 発泡体 ) are no longer relevant. In some embodiments, the infusion volume manager 124 essentially "restarts" depending on the replaced foam 216.

[0091] In some embodiments, the infusion volume manager 124 takes into account the immersion time 216 of the selected foam. For example, although the foam 216 can be immersed for a certain period of time after the delivery of the infusion fluid, the impact of the permanent compressive strain of the foam 216 can be reduced before the application of negative pressure. In some embodiments, the infusion volume manager 124 changes (e.g., reduces) the reduction coefficient θ based on the immersion time Δt 浸漬 In some embodiments, the infusion volume manager 124 determines a reduction coefficient θ adjusted in consideration of the immersion time Δt 浸漬 In some embodiments, the infusion volume manager 124 determines a reduction coefficient θ adjusted in consideration of the immersion time Δt adj In some embodiments, the infusion volume manager 124 uses the following formula, θ adj =θ - Δθ 浸漬 where Δθ 浸漬 is the adjustment amount determined based on Δt 浸漬 (e.g., Δθ 浸漬 = f(Δt 浸漬 )) In some embodiments, if it is possible to immerse the longer foam 216, Δθ 浸漬 becomes larger, and thus the adjusted reduction coefficient θ adj decreases. In some embodiments, the immersion time Δt 浸漬 is defined as the amount of time after the infusion fluid is provided to the wound site 202 but before negative pressure is applied at the wound site 202. In some embodiments, the immersion time Δt 浸漬 is input by the user via the user interface 106.

[0092] Referring now to FIG. 17, according to some embodiments, graph 1800 shows the operation of controller 110 over time. Graph 1800 shows, according to some embodiments, several NPWT cycles, shown as NPWT cycle 1802, NPWT cycle 1804, and NPWT cycle 1806. According to some embodiments, there are liquid injection cycles prior to the NPWT cycle, shown as injection cycle 1814, injection cycle 1816, and injection cycle 1818. According to some embodiments, NPWT cycle 1802 is shown to be executed at a vacuum pressure of 75 mmHg for a duration 1808, NPWT cycle 1804 is shown to be executed at a vacuum pressure of 75 mmHg for a duration 1810, and NPWT cycle 1806 is shown to be executed at a 150 mmHg vacuum pressure for a duration 1812. In some embodiments, the injection fluid volume V 注入 (k - 3) is provided in injection cycle 1814, and V 注入 (k - 2) is provided in injection cycle 1816, and V 注入 (k - 1) is provided in injection cycle 1818. According to some embodiments, to determine V 注入 (k) for the current injection cycle 1820, controller 110 selects an appropriate reduction factor θ from injection reduction database 122 based on the vacuum pressure (i.e., 150 mmHg) of the previously executed NPWT cycle (i.e., NPWT cycle 1806) and the duration of the previously executed NPWT cycle (i.e., duration 1812). Then, according to some embodiments, controller 110 determines V 注入 (k) using the following equation. V 注入 (k)=(V 注入 (k))(1 - θ) According to some embodiments, after injection cycle 1820 is executed, V 注入 (k) is stored as V 注入 (k - 1) for future injection cycles. Similarly, according to some embodiments, for injection cycle 1818, V 注入(k - 1) is determined based on NPWT cycle 1804 (i.e., duration 1810, vacuum pressure 75 mmHg) for V in infusion cycle 1816 注入 (k - 2), V 注入 (k - 2) is determined based on NPWT cycle 1802 (i.e., duration 1808, vacuum pressure 75 mmHg) for V 注入 (k - 3), etc.

[0093] Referring now to FIG. 19, according to some embodiments, graph 1900 shows the change in infusion volume provided over time to a wound (e.g., wound 218). According to some embodiments, the Y - axis of graph 1900 represents the volume of infusion fluid provided to wound site 202 for the corresponding infusion cycle (X - axis). As shown in graph 1900, since each volume of infusion fluid is determined based on the previous value of the infusion fluid provided, the decrease over time is non - linear. In some embodiments, if the controller 110 decreases the infusion volume of each infusion cycle by a standard amount, graph 1900 may be linear.

[0094] Method of control algorithm Referring now to FIG. 15, according to some embodiments, a process 1500 for determining the amount of infusion fluid to provide NPWT to a wound is shown. In some embodiments, process 1500 is executed by controller 110. In some embodiments, process 1500 is executed by one or more components of controller 110 (e.g., infusion volume manager 124).

[0095] Process 1500, according to some embodiments, includes receiving a treatment pressure setpoint p sp (step 1502). In some embodiments, the treatment pressure setpoint p sp is the vacuum pressure setpoint of the NPWT cycle. In some embodiments, the treatment pressure setpoint p spIt is received by the user interface manager 128. In some embodiments, the treatment pressure setpoint is received by the infusion volume manager 124. In some embodiments, the treatment pressure setpoint is received by a timer 118 for monitoring the amount of time, and NPWT is provided to the wound at the treatment pressure setpoint.

[0096] According to some embodiments, process 1500 includes infusing the wound area with a first infusion volume (step 1504). In some embodiments, step 1504 includes determining an initial infusion volume as the first infusion volume. In some embodiments, the initial infusion volume is determined based on an estimated wound volume. In some embodiments, the estimated wound volume is provided to the controller 110 via the user interface 106. In some embodiments, the wound volume is estimated by a wound volume manager 121. In some embodiments, the infusion volume manager 124 is configured to receive the estimated wound volume and determine the initial infusion volume. In some embodiments, the infusion volume manager 124 uses the wound volume and the relationship between the wound volume and the required infusion fluid to determine the initial infusion volume. In some embodiments, the relationship used by the infusion volume manager 124 to determine the initial infusion volume is an empirical relationship. In some embodiments, the control signal manager 130 receives the initial infusion volume from the infusion volume manager 124 and adjusts the operation of the pump 142 to provide an initial volume of infusion fluid to the wound site 202.

[0097] In some embodiments, process 1500 includes monitoring the amount of elapsed NPWT time (step 1506). In some embodiments, the amount of elapsed time is monitored by the timer 118. In some embodiments, the amount of elapsed time is the time during which NPWT is performed at the treatment pressure setpoint received in step 1502. In some embodiments, the monitored elapsed time is provided to the infusion volume manager 124.

[0098] According to some embodiments, process 1500 includes determining a second infusion volume and providing an infusion fluid of the second infusion volume to the wound area (step 1508). In some embodiments, the new or adjusted infusion volume is decreased relative to the initial or first (i.e., previously provided) infusion volume. In some embodiments, the second infusion volume is determined based on a reduction factor θ. In some embodiments, the reduction factor θ is determined based on a treatment pressure setpoint and the amount of elapsed time that NPWT has been provided at the treatment pressure setpoint. In some embodiments, step 1508 is performed by infusion volume manager 124. In some embodiments, step 1508 includes any of the functions of infusion volume manager 124 for determining V 注入 (k).

[0099] According to some embodiments, process 1500 includes replacing a first infusion volume value with a second infusion volume value (step 1510). In some embodiments, the first infusion volume value is replaced by the most recently determined second infusion volume value in response to step 1508 being completed. In some embodiments, step 1510 is performed by infusion volume tracker 126.

[0100] According to some embodiments, process 1500 includes repeating steps 1502-1510 until treatment is complete (step 1512). In some embodiments, step 1512 is performed by controller 110. In some embodiments, steps 1502-1510 are repeated until NPWT is complete or until the user changes the dressing of the wound.

[0101] Configuration of Exemplary Embodiments As used herein, the terms "about," "approximately," "substantially," and the like are intended to have a broad meaning consistent with the ordinary and accepted use by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those reviewing this disclosure that these terms are intended to allow the description and claiming of particular features without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that non-substantive or insignificant modifications or variations of the described and claimed subject matter are considered to be within the scope of this disclosure as set forth in the appended claims.

[0102] As used herein to describe various embodiments, the term "exemplary" and its variations are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to imply that such embodiments are necessarily special or the best examples).

[0103] The hardware and data processing components used to implement or perform the various processes, operations, exemplary logic, logic blocks, modules, and circuits described in connection with the embodiments disclosed herein can be implemented or performed by a general-purpose single-chip 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. The general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration of computing devices. In some embodiments, certain processes and methods may be performed by circuitry specific to a given function. Memory (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, flash memory, hard disk storage device) for storing data and / or computer code for performing or facilitating the various processes, layers, and modules described in this disclosure. The memory may be volatile memory or non-volatile memory, or may include both, 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 this disclosure. According to an exemplary embodiment, the memory is communicatively connected to the processor via a processing circuit and includes computer code for performing one or more processes described herein (e.g., by the processing circuit or processor).

[0104] The present disclosure contemplates a method, system, and program product on any machine-readable medium for achieving various operations. Embodiments of the present disclosure can be implemented using an existing computer processor or by a dedicated computer processor for a suitable system incorporated for this or another purpose, or by a hard-wired system. Embodiments included within the scope of the present disclosure include a program product that includes a machine-readable medium that carries or has machine-executable instructions or data structures stored thereon. Such a machine-readable medium may be any available medium that can be accessed by a general-purpose or dedicated computer or by another machine that includes a processor. By way of example, such a machine-readable medium may include RAM, ROM, EPROM, EEPROM, or other optical disk storage device, magnetic disk storage device, or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and that can be accessed by a general-purpose or dedicated computer or by another machine that includes a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data that cause a general-purpose computer, a dedicated computer, or a dedicated processing machine to execute a particular function or a group of functions.

Claims

1. an infusion system configured to provide an infusion fluid to a wound site including a wound and a wound dressing; providing a first amount of infusion fluid for a first infusion cycle; determining a second amount of infusion fluid for a second infusion cycle based on the first amount and a reduction factor, the second amount of infusion fluid being less than the first amount of infusion fluid; and configured to adjust operation of the infusion system to provide the second amount of infusion fluid to the wound site. A controller; including, Negative Pressure Wound Therapy (NPWT).

2. The NPWT system of claim 1 , wherein the reduction factor is determined based on a negative pressure of a negative pressure cycle and a duration of the negative pressure cycle.

3. The NPWT system of claim 1 , wherein the reduction factor is determined based on an amount of compression of the wound dressing over a period of time.

4. The NPWT system of claim 1 , wherein the wound dressing comprises one or more pieces of foam.

5. The NPWT system of claim 1 , wherein the controller is configured to receive an initial volume value of the wound from a user interface and to determine the first amount of infusion fluid using the initial volume value of the wound.

6. 2. The NPWT system of claim 1, wherein the controller is configured to determine the second amount of injectate for the second injection cycle by determining a reduction amount based on the reduction factor and the first amount.

7. The NPWT system of claim 6 , wherein the second amount is the difference between the first amount and the first amount multiplied by the reduction factor.

8. The NPWT system of claim 1 , wherein the reduction factor is a normalized value.

9. The NPWT system of claim 1 , wherein the controller is configured to select the reduction factor from a database of reduction factors based on a negative pressure of a negative pressure cycle and a duration of the negative pressure cycle.

10. 1. A NPWT device configured to provide a fluid to a wound and generate negative pressure at the wound for NPWT, comprising: monitoring the amount of negative pressure at the wound and the amount of treatment time; selecting a reduction factor based on the monitored negative pressure at the wound and the monitored amount of treatment time; determining a reduced value of liquid volume based on a previous value of liquid volume provided to the wound and the reduction factor to provide the reduced value of liquid volume to the wound; and configured to cause the NPWT device to provide the reduced volume of liquid to the wound. Includes a controller, An NPWT device, wherein the reduced value of fluid volume is less than the previous value of fluid volume provided to the wound.

11. The NPWT device of claim 10 , wherein the reduction factor is a percentage value.

12. The NPWT device of claim 11 , wherein the reduced value liquid volume is determined by decreasing the previous value liquid volume by the percentage value.

13. The NPWT device of claim 11, wherein the percentage value selected by the controller is between 3 and 6 percent when the monitored negative pressure at the wound is between 70 and 80 mmHg and the amount of treatment time elapsed is a predetermined amount of time.

14. 12. The NPWT device of claim 11, wherein the percentage value selected by the controller is between 7 and 9 percent when the monitored negative pressure at the wound is between 145 and 155 mmHg and the amount of treatment time elapsed is a predetermined amount of time.

15. The NPWT device of claim 11, wherein the percentage value selected by the controller is between 9 and 11 percent when the monitored negative pressure at the wound is between 195 and 205 mmHg and the amount of treatment time elapsed is a predetermined amount of time.

16. The NPWT device of claim 10 , wherein the reduction factor is determined based on an empirical relationship between an amount of treatment time at a negative pressure value and an amount of compression of the wound dressing.

17. 1. A method for providing a controlled amount of infusion fluid to a wound site, comprising: monitoring the amount of elapsed time of negative pressure wound therapy (NPWT); determining an amount of reduction based on a negative pressure setpoint of the NPWT during the elapsed time and an amount of elapsed time of the NPWT; determining a reduced infusion volume by reducing the infusion volume previously provided by said reduced volume; providing the reduced infusion rate of infusion fluid to the wound site via an infusion system.

18. 20. The method of claim 17, wherein the reduction amount is determined based on a reduction rate and the previously provided injection amount.

19. 20. The method of claim 18, wherein the rate of decrease is determined based on the amount of elapsed time and the negative pressure set point of the NPWT during the elapsed time.

20. 20. The method of claim 18, wherein the reduction rate is selected from a range of reduction rates based on the amount of elapsed time and the negative pressure set point of the NPWT during the elapsed time.

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