Negative pressure wound therapy system with dynamic fluid delivery

Abstract

The present application relates to negative pressure wound therapy systems utilizing dynamic fluid delivery. One implementation of the present disclosure is a negative pressure wound therapy (NPWT) system according to some embodiments. In some embodiments, the system includes an instillation system configured to provide instillation 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 instillation fluid for a first instillation cycle. In some embodiments, the controller is configured to determine a second amount of instillation fluid for a second instillation cycle based on the first amount and a reduction factor. In some embodiments, the second amount of instillation fluid is less than the first amount of instillation fluid. In some embodiments, the controller is configured to adjust operation of the instillation system to provide the second amount of instillation fluid to the wound site.

Description

[0001] This application is a divisional application of the application filed on May 5, 2020, with application number 202080031653.X and invention title "Negative Pressure Wound Treatment System Utilizing Dynamic Fluid Delivery".

[0002] Cross-references to related applications

[0003] This application claims the benefit of priority to U.S. Provisional Application No. 62 / 844,291, filed May 7, 2019, the entire contents of which are incorporated herein by reference. Background Technology

[0004] This disclosure relates generally to negative pressure wound therapy (NPWT) devices, and more specifically, to control algorithms for NPWT devices. Some NPWT devices introduce a clean fluid into the wound before aspirating negative pressure. Unfortunately, many systems deliver excessive infusion fluid to the wound or fail to consider changes in the wound's fluid capacity over time. This leads to frequent leaks and reduced NPWT quality. Therefore, there is a need for an NPWT device that takes into account the treatment duration and does not overfill the wound with infusion fluid. Summary of the Invention

[0005] One specific embodiment of this disclosure is a negative pressure wound therapy (NPWT) system according to some embodiments. In some embodiments, the system includes an infusion system and a controller configured to provide infusion fluid to a wound site. In some embodiments, the wound site includes a wound and a wound dressing. In some embodiments, the controller is configured to provide a first volume of infusion fluid for a first infusion cycle. In some embodiments, the controller is configured to determine a second volume of infusion fluid for a second infusion cycle based on the first volume and a reduction factor. In some embodiments, the second volume of infusion fluid is less than the first volume of infusion fluid. In some embodiments, the controller is configured to adjust the operation of the infusion system to provide the second volume of infusion fluid to the wound site.

[0006] In some implementations, the reduction factor is determined based on the negative pressure of the negative pressure cycle and the duration of the negative pressure cycle.

[0007] In some implementations, the reduction factor is determined based on the amount of compression of the wound dressing over a certain period of time.

[0008] In some implementations, the wound dressing includes one or more foam blocks.

[0009] In some implementations, the controller is configured to receive an initial volume value of the wound from a user interface and use that initial volume value of the wound to determine the first volume of infusion fluid.

[0010] In some implementations, the controller is configured to determine a second amount of drip fluid for the second drip cycle by determining the reduction amount based on the reduction factor and the first amount.

[0011] In some implementations, the second quantity is the difference between the first quantity and the first quantity multiplied by the reduction factor.

[0012] In some implementations, the reduction factor is a normalized value.

[0013] In some implementations, 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.

[0014] Another specific embodiment of this disclosure is an NPWT device according to some embodiments, the NPWT device being configured to supply fluid to a wound and generate negative pressure at the wound for NPWT. In some embodiments, the NPWT device includes a controller configured to monitor the negative pressure and the actual treatment time at the wound, select a reduction factor based on the monitored negative pressure and the monitored treatment time at the wound, determine a reduction value for the fluid volume supplied to the wound based on a previous value of the fluid volume supplied to the wound and the reduction factor, and cause the NPWT device to supply the reduced fluid volume to the wound. In some embodiments, the reduced fluid volume is less than the previous fluid volume supplied to the wound.

[0015] In some implementations, the reduction factor is a percentage value.

[0016] In some implementations, the reduction value of the fluid volume is determined by subtracting the percentage value from the previous value of the fluid volume.

[0017] In some implementations, if the negative pressure monitored at the wound site is between 70 mmHg and 80 mmHg, and the actual treatment time is a predetermined amount of time, the percentage value available for selection by the controller is between three percent and six percent.

[0018] In some implementations, if the negative pressure monitored at the wound site is between 145 mmHg and 155 mmHg, and the actual treatment time is a predetermined amount of time, the percentage value available for selection by the controller is between seven percent and nine percent.

[0019] In some implementations, if the negative pressure monitored at the wound site is between 195 mmHg and 205 mmHg, and the actual treatment time is a predetermined amount of time, the percentage value available for selection by the controller is between nine percent and eleven percent.

[0020] In some implementations, the reduction factor is determined based on an empirical relationship between the amount of treatment time under negative pressure and the amount of compression of the wound dressing.

[0021] Another specific embodiment of this disclosure relates to a method for adjusting a certain amount of infusion fluid and delivering that amount of infusion fluid to a wound site, according to some embodiments. In some embodiments, the method includes monitoring the duration of negative pressure wound therapy (NPWT), determining a reduction amount based on the negative pressure setpoint of NPWT during the duration of the duration and the duration of NPWT, determining a reduced amount of infusion fluid by reducing the reduction amount by a previously delivered infusion volume, and delivering the reduced amount of infusion fluid to the wound site via an infusion system.

[0022] In some implementations, the reduction amount is determined based on the reduction percentage and the previously provided infusion volume.

[0023] In some implementations, the reduction percentage is determined based on the actual time elapsed and the negative pressure setting of the NPWT during that actual time elapsed.

[0024] In some implementations, the reduction percentage is selected from a set of reduction percentages based on the amount of time elapsed and the negative pressure setting of the NPWT during that time elapsed. Attached Figure Description

[0025] Figure 1 This is a block diagram of an NPWT device for an NPWT application system according to some implementation schemes, the NPWT application system including a user interface, a controller and a pump.

[0026] Figure 2 It is based on some implementation plans. Figure 1 A block diagram of an NPWT application system, which includes tubing configured to provide drip fluid to a dressing at the wound site and to generate negative pressure at the wound site.

[0027] Figure 3 It is based on some implementation plans. Figure 2 The dressing on the wound site and a side view of the wound.

[0028] Figure 4 According to some implementation plans, after the dressing has been compressed to a certain amount... Figure 2 The dressing on the wound site and a side view of the wound.

[0029] Figure 5 It is based on some implementation plans. Figure 2 The dressing on the wound site and a top view of the wound.

[0030] Figure 6According to some implementation plans, after the dressing has been compressed to a certain amount... Figure 2 The dressing on the wound site and a top view of the wound.

[0031] Figure 7 It is based on some implementation plans. Figure 2 The dressing on the wound site and a side view of the wound.

[0032] Figure 8 This is based on some implementation plans after the wound volume is reduced. Figure 2 The dressing on the wound site and a side view of the wound.

[0033] Figure 9 It is based on some implementation plans. Figure 2 The dressing on the wound site and a top view of the wound.

[0034] Figure 10 This is based on some implementation plans after the wound volume is reduced. Figure 2 The dressing on the wound site and a top view of the wound.

[0035] Figure 11 It is based on some implementation plans that can be made by Figure 1 The controller uses a graph to determine the empirical relationship between the dressing / foam height and treatment time for the infusion fluid volume.

[0036] Figure 12 It is based on some implementation plans that can be made by Figure 1 The controller uses a graph to determine the empirical relationship between wound volume and treatment time for the infusion fluid volume.

[0037] Figure 13 It is based on some implementation plans. Figure 1 A block diagram of the controller for the NPWT device, including a drip volume manager that retrieves reduction factors from a drip reduction database.

[0038] Figure 14 It is based on some implementation plans. Figure 13 The table of reduction coefficients in the drip reduction database.

[0039] Figure 15 It is based on some implementation plans that can be made by Figure 1 The controller of the NPWT device uses a method to determine the adjusted drip volume for the NPWT device.

[0040] Figure 16 It is a graph of an NPWT cycle with multiple segments defined by changes in therapeutic pressure, based on some implementation schemes.

[0041] Figure 17It is a graph of multiple NPWT cycles and drip cycles over a certain period of time based on some implementation schemes.

[0042] Figure 18 It is a graph of various drip volume values ​​of dripping cycles over a certain period of time, based on some implementation schemes. Detailed Implementation

[0043] Overview

[0044] Referring generally to the accompanying drawings, a system, method, and apparatus for dynamically adjusting the amount of infusion fluid supplied to a wound, according to some embodiments, are illustrated. Typically, wound volume changes due to compression deformation of dressings / foams, tissue swelling, granulation tissue formation, and wound healing. This can result in a reduction in the amount of infusion fluid (e.g., saline) required during NPWT. Users often overfill fluid infusion reservoirs, thus supplying excessive fluid to the wound. This can lead to leakage, adversely affecting the healing process, and causing soiling if the infusion fluid leaks onto the user. Due to these factors, the required amount of infusion fluid decreases with the performance of NPWT. A controller receives various user and sensor inputs regarding the type of NPWT being performed, NPWT duration, NPWT vacuum pressure, etc. The controller can determine or select a reduction factor based on the NPWT vacuum pressure and NPWT duration. The controller can determine the reduced infusion volume for future fluid infusion cycles based on the reduction factor and the previously supplied infusion fluid volume. Advantageously, the controller can adjust the amount or volume of fluid supplied 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 derived from empirical relationships.

[0045] NPWT device

[0046] See now Figure 1 This image shows a front view of an NPWT device 100 according to an exemplary embodiment. According to some embodiments, the NPWT device 100 includes a user interface 106, a button 104, a housing 102, and a controller 110. In some embodiments, the controller 110 is configured to control the NPWT application system 200 to perform NPWT on the 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. According to some embodiments, the NPWT application system 200 may include a pump 142, an infusion fluid reservoir 204, a removal fluid reservoir 206, and tubing 208 and 210 (see...). Figure 2 In some implementations, the NPWT device 100 is configured to control VACVERAFLO. TMTherapy, PREVENA TM Therapy, ABTHERA TM Open abdominal negative pressure therapy or any other NPWT (e.g., controller 110 is configured to adjust the operation of pump 142 and / or NPWT administration system 200 to perform any of the NPWTs mentioned herein). In some embodiments, NPWT device 100 is configured to control the operation of any device (e.g., pump, vacuum system, infusion system, etc.) required to perform any of the NPWTs mentioned herein. In some embodiments, NPWT device 100 is a disposable NPWT device (dNPWT) and may have reusable / disposable components. For example, according to some embodiments, NPWT device 100 may be relatively lightweight (e.g., less than 5 pounds) and may be portable, allowing the patient to transport NPWT device 100 while it is still performing NPWT. Because NPWT device 100 may be portable, it can draw power from a portable power source (e.g., power supply 120, battery, etc.). The portable power source may have a limited energy capacity. Additionally, power supply 120 may be mains power (e.g., wall socket).

[0047] According to some embodiments, the user interface 106 is configured to display any one of alarms / warnings regarding at least one of the following: battery capacity, leakage, pump duty cycle / pump duty cycle value, etc., of the NPWT device 100. In some embodiments, the user interface 106 is configured to provide either visual or auditory warnings. In some embodiments, the user interface 106 allows a user to adjust the operation of the NPWT performed by the NPWT device 100. For example, a user can provide user input to the controller 110 via the user interface 106 to increase the therapeutic pressure setpoint p of the pump 142. sp The user interface 106 can adjust the type of NPWT performed, the parameters / operations of the NPWT performed, the duration of the NPWT performed, pause the NPWT, start the NPWT, and switch the NPWT device 100 to "change" mode (e.g., so that the wound dressing can be changed). In some embodiments, the user interface 106 displays the infusion fluid volume provided to the user. In some embodiments, the user interface 106 receives wound volume input from the user. In some embodiments, the user interface 106 is any of a resistive touchscreen interface, a surface acoustic wave touchscreen interface, a capacitive touchscreen interface, etc., configured to allow the user to control the NPWT device 100. In some embodiments, the user interface 106 is controlled by a button 104. In some embodiments, the button 104 is configured to control the user interface 106 and / or adjust the operation of the NPWT performed by the NPWT device 100.

[0048] According to some embodiments, the user interface 106 is also configured to display the operational status of the performed NPWT. For example, the user interface 106 may display any of the following: patient name, name of the responsible caregiver, type of NPWT currently being performed by the NPWT device 100, duration of the NPWT, remaining time in the current NPWT, vacuum pressure of the NPWT, or any other information related to the operational status of the NPWT and / or the NPWT device 100. For example, according to some embodiments, the user interface 106 is configured to display the battery (e.g., as shown in the image). Figure 2 The remaining battery life of the power supply 120 (shown), and / or the duty cycle of the system configured to provide vacuum pressure to the wound (e.g., pump 142). In some embodiments, the remaining battery life is the amount of energy remaining in the battery. In some embodiments, the remaining battery life is the amount of time remaining that the NPWT device 100 can maintain in its current operating state. In some embodiments, the user interface 106 is configured to communicatively connect to the controller 110. In some embodiments, the user interface 106 provides the controller 110 with any user input (e.g., treatment pressure setpoint, selected treatment type, etc.). In some embodiments, the controller 110 causes the user interface 106 to display NPWT operating parameters, alarms, warnings, requests, etc.

[0049] In some embodiments, the user interface 106 is a touchscreen. For example, the user interface 106 may be any of a capacitive touchscreen, a resistive touchscreen, etc. In some embodiments, the user interface 106 is configured to receive user input via the touchscreen and provide the user input to the controller 110.

[0050] NPWT application system

[0051] See now Figure 2 According to some embodiments, the NPWT application system 200 is shown in more detail. The NPWT application system 200 includes, according to some embodiments, a pump 142, an infusion fluid reservoir 204, a removal fluid reservoir 206, a return line 210, and a supply line 208. In some embodiments, the pump 142 is configured to draw negative pressure at the wound site 202 via the return line 210. In some embodiments, the pump 142 operates at a treatment pressure setpoint p. spNegative pressure is aspirated at wound site 202. In some embodiments, the NPWT application system 200 is configured to provide a quantity of infusion fluid (e.g., saline solution, etc.) to the internal volume 222 of wound site 202 or wound 218 via supply line 208. In some embodiments, the NPWT application system 200 provides infusion fluid from infusion fluid reservoir 204 to the internal volume 222 of wound site 202 and / or wound 218 via supply line 208. In some embodiments, the infusion fluid is a sterile fluid that can be used for wounds requiring rinsing to prevent infection or reduce the amount of wound infection.

[0052] The supply tube 208 and return tube 210 can be any form of tubing, medical tubing, flexible tubing, etc., having an internal volume configured to facilitate the flow of fluids, gases, solutions, etc., and possessing sufficient structural strength to maintain negative pressure (e.g., sufficient strength to prevent collapse when negative pressure is generated within the internal volume). In some embodiments, the supply tube 208 and return tube 210 are connected at a first end to a pump 142 and / or an infusion fluid reservoir 204 and / or a removal fluid reservoir 206. For example, the supply tube 208 may be fluidly connected to the infusion fluid reservoir 204 to provide fresh infusion fluid to the wound site 202. Similarly, the return tube 210 may be fluidly connected to the removal fluid reservoir 206 to remove fluid 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 positive pressure, thereby pushing the infusion fluid into the wound site 202 via the supply line 208. In some embodiments, pump 142 provides negative pressure to the wound site 202 via the return line 210. In some embodiments, the negative pressure provided via the return line 210 provides negative pressure at an internal volume 250. In some embodiments, the negative pressure at the internal volume 250 generated by pump 142 draws infusion fluid from the infusion fluid reservoir 204. In some embodiments, the fluid regulating device is positioned in line with the supply line 208 to ensure that an adequate volume or sufficient flow rate of infusion fluid is provided to the wound site 202 via the supply line 208. In some embodiments, the NPWT application system 200 is actuated between NPWT cycles and fluid infusion cycles. For example, according to some embodiments, pump 142 is shown as receiving a control signal (e.g., from controller 110). In some embodiments, pump 142 initiates a fluid drip cycle, wherein drip fluid is supplied from drip fluid reservoir 204 to wound site 202 via supply line 208. In some embodiments, the entire volume of drip fluid in drip fluid reservoir 204 is supplied to wound site 202. In some embodiments, pump 142 automatically supplies a specific amount of drip fluid from drip fluid reservoir 204 to wound site 202. For example, in some embodiments, drip fluid reservoir 204 contains 500 mL of drip fluid, but pump 142 operates to supply only 15 mL of drip fluid to wound site 202. In some embodiments, pump 142 performs a fluid drip cycle by supplying drip fluid to wound site 202. In some embodiments, in response to supplying X amount of drip fluid to wound site 202 during a fluid drip cycle, pump 142 switches to an immersion mode of an immersion cycle, wherein the drip fluid is allowed to immerse wound site 202.In some embodiments, the immersion mode includes holding the pump 142 in an operational state for a predetermined amount of time to allow the infused fluid to adequately immerse the wound site 202. In some embodiments, in response to the completion of the fluid infusion cycle and immersion cycle (e.g., the immersion cycle may be optional), the pump 142 is p via the return line 210. sp The suction negative pressure reaches a time period Δt. In some implementations, the pump is 142p. sp A negative pressure is drawn to perform the NPWT cycle. In some embodiments, during the NPWT process, pump 142 switches between a fluid drip cycle and an NPWT cycle to provide drip fluid to and remove drip fluid from the wound site 202.

[0053] Still referencing Figure 2 Wound site 202 includes wound 218, seal 214, and foam 216. In some embodiments, seal 214 is configured to seal along the entire circumference of wound 218. In some embodiments, seal 214 is configured to seal along a wound periphery surface 212 surrounding wound 218. In some embodiments, seal 214 includes an adhesive to retain and seal seal seal 214 to wound periphery surface 212. In some embodiments, seal 214 is configured to seal along a patient's surface surrounding wound periphery surface 212. In some embodiments, seal 214 covers and seals substantially the entire surface of wound 218 contained therein. In some embodiments, seal 214 defines an internal volume 250. In some embodiments, internal volume 250 is defined as any space between seal 214 and the surface covered by seal 214. For example, internal volume 250 may include an internal wound volume 222.

[0054] Supply line 208 and return line 210 are configured to be hermetically connected to seal 214 such that they are fluidly connected to internal volume 250. In some embodiments, return line 210 provides internal volume 250 with negative pressure generated by pump 142. In some embodiments, return line 210 facilitates the evacuation of air, gas, or liquid from internal volume 250. Similarly, according to some embodiments, supply line 208 is configured to provide drip fluid to internal volume 250. In some embodiments, supply line 208 is fluidly and hermetically connected to internal volume 250. In some embodiments, supply line 208 and return line 210 are hermetically and fluidly connected to internal volume 250 defined by seal 214 via connectors 224 and 226, respectively.

[0055] See still Figure 2According to some embodiments, foam 216 is shown disposed within the internal volume 222 of wound 218. In some embodiments, foam 216 comprises one or more foam blocks configured to substantially fill the internal volume 222 of wound 218. In some embodiments, foam 216 is configured to absorb drip fluid supplied from drip fluid reservoir 204 via supply line 208. In some embodiments, foam 216 is configured to prevent particulate matter (e.g., scar tissue, scab, etc.) from entering return line 210. In some embodiments, foam 216 is granulafoam. TM According to some embodiments, foam 216 includes an outer surface 234. In some embodiments, at least a portion of the outer surface 234 of foam 216 is substantially adjacent to the wound surface 220 of wound 218. In some embodiments, the entire portion of the outer surface 234 of foam 216 is adjacent to the wound surface 220 of wound 218. In some embodiments, foam 216 facilitates the delivery of infusion fluid to wound 218 (e.g., at wound surface 220). In some embodiments, the outer surface 234 of foam 216 is in contact with the wound surface 220 of wound 218.

[0056] According to some embodiments, foam 216 includes an edge 235. In some embodiments, the edge 235 is the perimeter of foam 216 or defines that perimeter. Similarly, according to some embodiments, wound 218 includes an edge 221. In some embodiments, the edge 221 of the wound is the perimeter of wound 218 or defines that perimeter. In some embodiments, wound 218 has a depth 232. In some embodiments, the perimeter of wound 218 increases with depth 232. For example, the perimeter of wound 218 may be greater than the perimeter of wound 218 at the surface 212 surrounding the wound (e.g., the overall size of wound 218 may increase at various depths).

[0057] Changes in wound volume and foam volume

[0058] See now Figures 3 to 6 According to some implementation schemes, wound 218 and foam 216 are shown in more detail. (e.g.) Figure 3As shown, according to some embodiments, wound 218 has a total width (or length) shown as distance 230, and foam 216 has a total width (or length) shown as distance 228. In some embodiments, the distance 228 of foam 216 is substantially equal to the distance 230 of wound 218. In some embodiments, at the start of NPWT, the distance 228 of foam 216 is substantially equal to the distance 230 of wound 218. For example, foam 216 may be filled within the internal volume 222 of wound 218 such that foam 216 substantially fills the entire internal volume 222 of wound 218. In some embodiments, foam 216 is compressible such that it can be filled into the internal volume 222 of wound 218. In some embodiments, because foam 216 is compressible, it can change shape, diameter, perimeter, length, area, volume, etc., throughout the NPWT process.

[0059] In some implementations, the required amount of dripping fluid V instillation The volume 222 of the wound 218 varies throughout the NPWT process. For example, in some embodiments, the volume 222 of the wound 218 changes (e.g., decreases) due to swelling (i.e., edema) of the surrounding or wound tissue, healing (e.g., shrinkage of the wound 218 as it heals), granulation tissue formation within the wound 218, and compression (e.g., reduction) of the foam 216. In some embodiments, any of the volume changes mentioned above (e.g., granulation tissue formation, healing, edema, compression, etc.) alters the required amount V of the infusion fluid. For example, in some embodiments, the required amount V of the infusion fluid decreases during the NPWT process. Other systems may overfill the internal volume 250 with infusion fluid, thereby increasing the likelihood of leakage, seal failure, and NPWT quality degradation. Additionally, seal leakage may allow air to enter the internal volume 250, thereby degrading the healing process and reducing the efficiency of the pump 142. Advantageously, the controller 110 is configured to reduce the amount of infusion fluid supplied to the internal volume 250 for subsequent fluid infusion cycles, as described in more detail below.

[0060] According to some implementation schemes, the compression of foam 216 is the amount V of the required dripping fluid. instillation A key reason for the variation. In some implementations, foam 216 undergoes compression deformation. In some implementations, the compression deformation of foam 216 is the amount V of the desired drip fluid. instillation The most significant factor that changes over time. In some implementations, the compression of foam 216 is based on the amount of compression (e.g., negative pressure at an internal volume of 250, p). spThe temperature applied to foam 216 (e.g., the temperature of wound 218, body temperature, etc.) and the time (e.g., treatment time) are predictable. In some embodiments, the fluid capacity (C) of foam 216 decreases as the volume, height, width, area, perimeter, etc. of foam 216 decreases (e.g., when foam 216 is compressed). foam The deformation of foam 216 during compression (e.g., fluid capacity C) decreases. In some embodiments, when foam 216 is compressed (e.g., fluid capacity C...), the deformation decreases. foam When the volume of fluid to be dripped is reduced (V), the required amount of fluid is V. instillation Decrease.

[0061] In some embodiments, when seal 214 is removed (e.g., during dressing change, during seal change, etc.), foam 216 is exposed to atmospheric pressure and expands. In some embodiments, foam 216 increases in size to return to its original height, width, volume, etc., in response to exposure to atmospheric pressure. However, in some embodiments, foam 216 cannot expand (e.g., re-inflate) to its original height, width, volume, etc. In some embodiments, foam 216 cannot expand to its original height, width, volume, etc., as NPWT continues. For example, in some embodiments, foam 216 does not re-inflate to its original height due to the presence of drip fluid or air in foam 216 that was supplied to foam 216 throughout the previous NPWT implementation (e.g., a previous round of NPWT). Additionally, tissue material may accumulate in foam 216, which reduces the fluid capacity of foam 216. In some embodiments, as NPWT continues, the amount of re-inflation of foam 216 (e.g., the degree to which foam 216 returns to its original size, volume, height, width, etc.) decreases. In some embodiments, if foam 216 fails to re-inflate, this affects the static volume occupied by foam 216 before it appears to inflate due to fluid delivery. In some embodiments, controller 110 is configured to adjust the amount V of the desired infusion fluid supplied by NPWT application system 200 to wound site 202. instillation To take into account the amount of compression of foam 216.

[0062] See now Figure 3 and Figure 4 The image shows foam 216 before and after compression according to some implementation schemes. Figure 3 This can refer to foam 216 before it receives the dripping fluid. Figure 4 This refers to foam 216 after it has been exposed to negative pressure and temperature (e.g., human body temperature) for a certain period of time, according to some implementation schemes. For example... Figures 3 to 4As shown, foam 216 has a height 238 and wound 218 has a height / depth 232. In some embodiments, the height 238 of foam 216 is initially substantially equal to the height / depth 232 of wound 218. In some embodiments, after foam 216 has been exposed to negative pressure and temperature for a certain amount of time (e.g., treatment time), Figure 4 The height of the foam decreases by 238. (For example...) Figure 4 As shown, according to some embodiments, after foam 216 has been exposed to negative pressure for a certain period of time, the height 238 of foam 216 is less than the height / depth 232 of wound 218. In some embodiments, the reduced height 238 of foam 216 affects the amount V of the required infusion fluid to be delivered to wound site 202. instillation .

[0063] See now Figures 3 to 6 According to some implementation schemes, the width 228 of foam 216 can be reduced in a manner similar to the reduction in height 238 of foam 216. Figure 3 and Figure 5 In some embodiments, the total width 228 of foam 216 is substantially equal to the total width 230 of wound 218. In some embodiments, Figure 3 and Figure 5 The image shows foam 216 before it has been exposed to negative pressure and temperature for a certain period of time. In some embodiments, such as Figure 5 As shown, the total perimeter 235 of foam 216 is initially substantially equal to the perimeter 221 of wound 218. In some embodiments, after foam 216 has been exposed to negative pressure and temperature for a certain period of time, the total perimeter 235 of foam 216 decreases, as... Figure 6 As shown. In some embodiments, the reduction in the perimeter 235 of foam 216 is due to a reduction in the width 228 of foam 216. For example... Figure 6 As shown, the perimeter 235 of foam 216 has been reduced by an amount such that the perimeter 235 is offset by a distance 236 from the perimeter 221 of wound 218. In some embodiments, the reduction in height 238 and / or width 228 and / or perimeter 235 of foam 216 should affect the amount of fluid V required to be infused to wound site 202. instillation In some implementations, the height 238, perimeter 221, and / or width 228 are reduced relative to the fluid capacity C of the foam 216. foam Relatedly, for example, due to the accumulation of wound tissue material within foam 216, the height 238 and perimeter 221 can be reduced, which decreases the fluid capacity C of foam 216. foam In some implementations, the fluid capacity C foam The change indicates the required amount of fluid V to be infused into wound 218. instillation The necessary changes.

[0064] See now Figures 7 to 10 This illustrates variations in the overall size of wound 218 according to some embodiments. In some embodiments, the overall size of wound 218 may change due to any of swelling, edema, and healing. In some embodiments, the change in the overall size of wound 218 reduces the internal volume 222 of wound 218. In some embodiments, when the internal volume 222 of wound 218 changes (e.g., decreases), the required amount V of infusion fluid should be provided to wound site 202. instillation Changes (e.g., reductions). In some embodiments, the volume 222 of the wound 218 is reduced due to granulation tissue formation.

[0065] See now Figure 7 According to some implementations, wound 218 is shown as being in its initial state. In some implementations, such as Figure 7 The initial state of wound 218 shown is the state of wound 218 before NPWT begins. According to some embodiments, wound 218 has a total width of 230 in the initial state. In some embodiments, wound 218 has a total height of 232 in the initial state. Figure 8 As shown, when NPWT is performed on wound 218, according to some embodiments, at least one of the total width 230 and total height 232 of the wound is reduced. In some embodiments, the reduction of either the total height 232 or the total width 230 of wound 218 reduces the internal volume 222 of wound 218. In some embodiments, the reduction of the internal volume 222 of wound 218 reduces the amount V of the required drip fluid to be supplied to wound site 202 via supply tube 208. instillation Reduce. In some embodiments, the controller 110 is configured to predict and compensate for the required amount of dripping fluid V relative to time. instillation This takes into account the volume 222 of the wound 218 as it heals. According to some embodiments, the internal volume 222 of the wound 218 may be reduced or altered due to any of the reasons listed above (e.g., healing, granulation tissue formation, swelling, edema, etc.).

[0066] like Figures 9 to 10 As shown, according to some embodiments, the perimeter 221 of wound 218 may vary as NPWT continues (e.g., due to edema, healing, granulation tissue formation, swelling, etc. of wound 218). In some embodiments, the perimeter 221 of wound 218 decreases as NPWT continues due to any of the factors mentioned above. In some embodiments, as the perimeter 221 of wound 218 decreases, the required amount V of infused fluid in wound 218 also decreases. instillationReduction. In some embodiments, when the wound 218 changes, the size, shape, perimeter, width, height, etc., of the foam 216 changes (e.g., decreases). For example, as... Figure 10 As shown, according to some embodiments, the perimeter 221 of wound 218 is reduced by an offset distance 237 relative to the initial perimeter 221 of wound 218. Similarly, according to some embodiments, the perimeter 235 of foam 216 is also reduced.

[0067] According to some implementations, controller 110 is configured to adjust the required amount V of infusion fluid supplied to wound site 202. instillation This is to account for either the volume change of wound 218 or the volume change of foam 216. In some embodiments, controller 110 uses empirical relationships to determine the required amount V of infusion fluid. instillation And / or increase or decrease the required amount of dripping fluid V instillation The amount is taken into account for changes in the volume of wound 218 and / or changes in the volume of foam 216. In some embodiments, the change in the volume of foam 216 is due to compression deformation of foam 216 as described above. In some embodiments, the change in the volume of wound 218 is due to any of the following: edema, swelling, wound healing, granulation tissue formation, etc.

[0068] Experience relationship

[0069] See now Figures 11 to 12 Graphs 1100 and 1200 illustrate the height variation of foam 216 and the volume variation of wound 218 according to some embodiments. In some embodiments, the empirical relationship shown in graphs 1100 and 1200 is used to determine the amount V of the desired drip fluid used by controller 110. instillation Factors. In some implementations, the empirical relationships shown in graphs 1100 and 1200 are used to determine whether to increase or decrease the required amount V of drip fluid. instillation The amount. In some implementations, the required amount V of dripping fluid is increased or decreased. instillation The factor quantity is called the reduction factor θ.

[0070] See now Figure 11Graph 1100 shows the change in height 238 (Y-axis) of foam 216 relative to treatment time (X-axis) according to some embodiments. In some embodiments, graph 1100 includes scattered data 1102. In some embodiments, scattered data 1102 is empirical data determined by testing. In some embodiments, scattered data 1102 is determined, for example, by measuring an initial value of height 238 of foam 216, performing NPWT for a certain amount of time, and measuring the value of height 238 of foam 216 after NPWT has been performed. For example, according to some embodiments, a single piece of foam 216 with an initial height 238 value of 30 mm can be used at 125 mmHg (e.g., p). sp The foam 216 is exposed to a saline solution (e.g., via dripping fluid) at a negative pressure and a temperature of 35 degrees Celsius (approximately human body temperature) for a predetermined amount of time (e.g., 24 hours). According to some embodiments, after the predetermined amount of time has elapsed, another value of the height 238 of the foam 216 is recorded (e.g., the height 238 of the foam 216 is 29 mm). For a specific set of temperatures and pressures (p... sp Under certain conditions, the process can be repeated to determine data points relating the height 238 of foam 216 to treatment time (e.g., determining data point 1102). For example, in some embodiments, after exposing foam with an initial height 238 value of 30 mm to the same conditions for an additional 12 hours, the final height 238 value is recorded as 28 mm. This produces data points for foam 216 according to some embodiments: when tested at 125 mmHg and 35 degrees Celsius, 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 foam 216. According to some embodiments, the test can be continued to determine additional data points for various combinations of temperature and pressure. For example, according to some embodiments, the test can be performed against negative pressures p such as 75 mmHg, 152 mmHg, 200 mmHg, etc. sp Or any other p typically used during NPWT sp The value is used to execute.

[0071] See still Figure 11 According to some implementations, a linear trend line 1106 or a nonlinear relationship 1104 can be determined based on the scattered data 1102 determined using the above-described testing procedure. In some implementations, this can be done for various test parameters (e.g., p). sp Each set of scattered data (various values, various temperature values, etc.) is used to determine a linear trend line 1106 and / or a nonlinear relationship 1104. In some implementations, the relationship between the change in height h (i.e., the height 238 of foam 216) and treatment time has the following relationship:

[0072] Δh=f foam (T, Δt, p) sp )

[0073] Where f foam For Δh and T, Δt and p sp The relationship between T and p is given, where T is the temperature the foam was exposed to during the test, Δt is the actual treatment time, and p is the temperature of the foam. sp The pressure to which the foam is exposed during testing. In some implementations, f foam Depending on the various properties of the foam, f foam This represents the linear relationship between Δt and Δh. In some implementations, f foam This represents the nonlinear relationship between Δt and Δh. In some implementations, this applies to T and p, which can be used during NPWT. sp Each combination determines f foam In some implementations, for each group of T and p sp Perform multiple tests and multivariate regression based on T, Δt, and p. sp Determine f with respect to Δh foam .

[0074] In some implementations, the height change Δh of foam 216 due to NPWT is proportional to the fluid capacity of foam 216 (i.e., C). foam ∝Δh). In some implementations, as the height h of foam 216 decreases, the fluid capacity C foam It also decreases. In some implementations, as the fluid capacity C... foam The amount of dripping fluid V required to be reduced (e.g., due to compression deformation, the internal structure of foam 216, etc.) instillation It also decreases. Thus, according to some implementation schemes, as foam 216 changes over time during NPWT, the required amount of dripping fluid V... instillation It also changes over time. According to some implementations, controller 110 is configured based on Δt and p. sp Reduce the amount V of drip fluid used for subsequent fluid dripping cycles. instillation .

[0075] Now for reference Figure 12 Graph 1200 shows the internal volume 222 (V) of wound 218 according to some embodiments. woundThe change (Y-axis) relative to treatment time (X-axis). In some embodiments, the internal volume 222 of wound 218 is directly related to the fluid capacity of wound 218 (e.g., the amount of infusion fluid that wound 218 can contain). In some embodiments, graph 1200 includes scattered data 1202. In some embodiments, scattered data 1202 is the result of various tests. For example, according to some embodiments, scattered data 1202 may represent the value of the internal volume 222 of wound 218 as measured throughout NPWT administration. In some embodiments, it is for various temperatures T (e.g., various human body temperatures) and various negative pressure setpoints p. sp Scattered data 1202 is collected for various NPWT applications. In some embodiments, a linear trend line 1206 is fitted to the scattered data 1202 to determine the relationship between the internal volume 222 of the wound 218 and the treatment time. In some embodiments, a nonlinear relationship 1204 is determined based on the scattered data 1202 to determine the nonlinear relationship between the internal volume 222 of the wound 218 and the treatment time. In some embodiments, the trend line 1206 and / or the nonlinear 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 can use the predicted change in the internal volume 222 of the wound 218 to determine the required amount V of infusion fluid. instillation The changes.

[0076] In some implementations, either of the relationships described in the reference graphs 1100 and 1200 above is used to determine the amount V of the desired drip fluid that the controller 110 adjusts. instillation The coefficient θ. In some implementations, the controller 110 stores various NPWT parameters (e.g., various p... sp Values, various T values, various p values sp One or more θ values ​​(combined with T values, etc.) are used to determine the amount V of the adjusted drip fluid. instillation In some implementations, controller 110 uses a function to determine the coefficient θ based on various NPWT parameters. In some implementations, the value of coefficient θ is determined based on either of the relationships shown in graphs 1100 and 1200.

[0077] Controller configuration

[0078] See now Figure 13 According to some embodiments, controller 110 is shown in more detail. According to some embodiments, controller 110 is configured to determine the desired amount V of dripping fluid. instillationThe controller 110 adjusts the amount of infusion fluid introduced into the wound site 202 to ensure that no excessive infusion fluid is delivered to the wound site 202. In some embodiments, the controller 110 advantageously reduces the likelihood of excessive infusion fluid (such as saline solution) being introduced into the wound site 202. Some systems may require the user to manually determine the amount of infusion fluid to be 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 the NPWT.

[0079] According to some embodiments, controller 110 is configured to control the operation of pump 142 to perform NWPT. In some embodiments, controller 110 is configured to control pump 142 and / or NPWT application system 200 to deliver a determined infusion volume V to wound site 202 for fluid infusion circulation. instillation According to some embodiments, controller 110 is shown as including processing circuitry, shown as processing circuitry 112. Processing circuitry 112 may be configured to perform some or all of the functions of controller 110. Processing circuitry 112 is shown as including a processor, shown as processor 114. 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 gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Processor 114 may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. Processor 114 may also be implemented as a combination of computing devices, such 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. In some embodiments, specific processes and methods may be performed by circuitry specific to a given function. Processing circuitry 112 also includes memory, shown as memory 116. Memory 116 (e.g., memory, memory cell, storage device) may include one or more means (e.g., RAM, ROM, flash memory, hard disk storage device) for storing data and / or for performing or facilitating the various processes, layers, and modules described herein. Memory 116 may be or include volatile or non-volatile memory and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein. According to an exemplary embodiment, memory 116 is communicatively connected to processor 114 via processing circuitry 112 and includes computer code for (e.g., via processing circuitry or processor) performing one or more of the processes described herein.

[0080] See still Figure 13According to an exemplary embodiment, controller 110 is shown including a power interface, shown as power interface 134. According to some embodiments, power interface 134 is configured to draw power from a power source (shown as power source 120) to power controller 110. In some embodiments, power source 120 is any kind of permanent and / or temporary power source. In some embodiments, power source 120 is a battery. In some embodiments, power interface 134 is a connection port for a permanent power source (e.g., AC power and / or DC power), such as a wired 24VAC connection. In other embodiments, power interface 134 includes a port for a permanent power source and / or power circuitry configured to receive and convert power from power source 120. In some embodiments, power interface 134 is configured to receive power from both a permanent power source (e.g., a socket) and a temporary power source (e.g., a battery). According to some embodiments, power interface 134 may include any number of electronic components necessary to receive, convert, and power controller 110, such as resistors, transistors, capacitors, inductors, diodes, transformers, switches, etc. In some embodiments, if power interface 134 is configured to receive power from a temporary power source (e.g., if power source 120 is a battery), power interface 134 can output power level data of power source 120 to processing circuitry 112. The power level data may indicate the amount of energy remaining in power source 120 (e.g., the amount of kilowatt-hours remaining in power source 120). In some embodiments, power source 120 is a replaceable power source (e.g., a battery). In some embodiments, power source 120 is one or more disposable batteries. For example, according to some embodiments, power source 120 is one or more disposable 12-volt batteries. In some embodiments, power source 120 is one or more rechargeable batteries. In some embodiments, power source 120 is configured to be temporarily disconnected from power interface 134 when a replaceable power source must be replaced (e.g., if power source 120 is one or more replaceable batteries, power source 120 can be disconnected when the battery is low and must be replaced).

[0081] See still Figure 13According to some embodiments, controller 110 is shown to include a communication interface 132. Communication interface 132 is configured to facilitate communication between controller 110 and various external devices, sensors, systems, etc. According to some embodiments, communication interface 132 is configured to receive input from at least one of pump 142, user interface 106, sensors, devices, etc. In some embodiments, communication interface 132 receives commands and / or requests from user interface 106. For example, user interface manager 128 may receive commands from user interface 106 via communication interface 132 to switch NPWT device 100 between various operating modes or adjust the operating characteristics of the NPWT being performed by NPWT device 100 (e.g., increase pressure setpoint, increase treatment time, pause treatment, etc.). According to some embodiments, communication interface 132 is also configured to receive information from pump 142 regarding actual treatment pressure or pump duty cycle. In some embodiments, communication interface 132 is configured to facilitate communication between user interface 106 and user interface manager 128. Communication interface 132 may include any wired or wireless interface. For example, according to some embodiments, communication interface 132 may include a universal serial bus interface. In other embodiments, communication interface 132 includes one or more wireless transceivers configured to wirelessly connect controller 110 to various external devices, systems, sensors, etc. (e.g., user interface 106 and pump 142). In some embodiments, communication interface 132 is configured to facilitate communication between control signal manager 130 and pump 142. For example, control signal manager 130 may determine control signals for pump 142 and / or NPWT application system 200. In some embodiments, communication interface 132 facilitates communication between pump 142 and control signal manager 130, enabling control signal manager 130 to output control signals to pump 142 to adjust the operation of pump 142.

[0082] See still Figure 13 According to some embodiments, memory 116 is shown as including user interface manager 128. In some embodiments, user interface manager 128 is configured to receive one or more inputs from user interface 106. In some embodiments, user interface manager 128 is configured to receive one or more treatment parameters from user interface 106 via communication interface 132. The one or more treatment parameters may include the selected treatment type, treatment pressure setpoint p sp Temperature (e.g., local temperature at wound site 202), total treatment time t total And the volume V of wound 218 wound Either of the above. In some implementations, the user interface manager 128 receives treatment selections from the user interface 106 via the communication interface 132 and determines psp 、T、t total V wound One or more of these. In some implementations, the user interface manager 128 provides p to the drip volume manager 124. sp T, V wound and t total Any of these inputs. In some implementations, the drip volume manager 124 uses any of these inputs to use p sp T, V wound and t total Either of these factors determines the drip volume (i.e., the volume) V of the fluid being dripped. instillation In some implementations, T is assumed to be normal human body temperature. In some implementations, p sp The negative pressure setting value is input by the user via user interface 106. In some implementations, p sp The negative pressure setting value is determined by the user interface manager 128 based on the treatment type selected or received from the user interface 106.

[0083] See still Figure 13 According to some embodiments, memory 116 is shown as including timer 118. In some embodiments, timer 118 is configured to track the amount of time elapsed since the NPWT was performed. For example, according to some embodiments, timer 118 may record the start time and compare the start time of the NPWT with the current time value to determine the total amount of time since the NPWT was performed. In some embodiments, timer 118 is configured to provide the total amount of time elapsed to infusion volume manager 124 and / or wound volume manager 136. In some embodiments, the elapsed time is Δt. In some embodiments, timer 118 records the time of treatment pause (e.g., for dressing change). In some embodiments, timer 118 receives p from any of the user interface manager 128, communication interface 132, etc. sp In some implementations, if p sp When the blood pressure is changed (e.g., increased from 75 mmHg to 100 mmHg), timer 118 records p. sp The time of change. In some implementations, timer 118 tracks the time at a specific therapeutic pressure p. sp The time amount of NPWT already provided is specified. For example, according to some embodiments, if the NPWT device 100 provides NPWT at 100 mmHg for a first time period and at 125 mmHg for a second time period, then timer 118 tracks the time amounts of the first and second time periods. In some embodiments, timer 118 is configured to provide the drip volume manager 124 with the time amount from the previous pressure setpoint p. spThe actual time elapsed since the change, Δt. In some implementations, timer 118 is configured to recognize events (e.g., treatment start time, pressure setpoint p). sp (Changes, etc.), and records the time Δt between successive events and / or the actual time Δt since a previous event. Timer 118 can provide Δt to the infusion volume manager 124 and / or the wound volume manager 136.

[0084] See still Figure 13 According to some embodiments, memory 116 is shown as including wound volume manager 136. In some embodiments, wound volume manager 136 is configured to determine the volume V of wound 218. wound In some implementations, the wound volume manager 136 is configured to provide the determined volume V of the wound 218 to the infusion volume manager 124. wound In some implementations, the wound volume manager 136 is based on the actual elapsed time Δt since NPWT startup and the self-healing pressure setpoint p. sp Actual time consumption Δt since the change, initial wound volume V wound，initial And either of the empirical relationships determines V wound In some implementations, at the start of NPWT, V is provided to the wound volume manager 136 via user interface 106 and communication interface 132. wound，initial For example, a user can measure the initial volume of wound 218 and input the initial volume of wound 218 via user interface 106. In some embodiments, wound volume manager 136 uses the above reference. Figure 12 A more detailed description of the empirical relationship determines the current volume of wound 218. For example, wound volume manager 136 can receive the actual time elapsed since NPWT was started, the pressure p during NPWT execution, etc. sp And use empirical relationships to determine V wound The current value. In some implementations, the wound volume manager 136 determines V. wound The amount that decreases over a certain period of time (e.g., since the infusion volume manager 136 was started). In some embodiments, the wound volume manager 136 provides V to the infusion volume manager 124. wound .

[0085] See still Figure 13 According to some embodiments, memory 116 is shown to include a drip volume tracker 126. In some embodiments, the drip volume tracker 126 is configured to record / track the drip volume V of the NPWT within a previous cycle. instillationFor example, according to some embodiments, the infusion volume tracker 126 may record the amount V of infusion fluid supplied to the wound site 202 during a previous fluid infusion cycle (e.g., under fluid infusion cycle k-1). instillation In some implementations, the infusion volume tracker 126 records and tracks the amount of infusion fluid delivered to the wound 218 during a previous fluid infusion cycle (e.g., V). instillation In some implementations, the infusion volume tracker 126 receives the infusion volume V. instillation(k) The drip volume manager 124 determines this for the current fluid dripping cycle (e.g., the current NPWT cycle, the current fluid dripping cycle, etc.). For example, if the NPWT device 100 is currently set to drip 1 cubic centimeter of fluid within a dripping fluid cycle, and then within a 24-hour NPWT cycle... sp If an NPWT is provided at a pressure of 100 mmHg, the drip volume tracker 126 records the drip fluid volume of 1 cubic centimeter for the first fluid drip cycle. If the NPWT device 100 is set to drip 2 cubic centimeters of fluid in the second drip fluid cycle, and then in the second 24-hour NPWT cycle at p sp If an NPWT is provided at a pressure of 125 mmHg, the drip volume tracker 126 can provide 1 cubic centimeter to the drip volume manager 124 as the amount V of the previously dripped fluid. instillaion (k-1), which can be used by the drip volume manager 124 to determine X2 for the second drip fluid cycle. When the second 24-hour NPWT cycle is completed, the drip volume tracker 126 can store X2 as the amount V of the previously dripped drip fluid. instillation (k-1), and can store the infusion volume X1 from the first cycle as V instillation (k-2). In this way, according to some embodiments, the drip volume tracker 126 records the drip volume of the previously completed NPWT or fluid dripping cycle. In some embodiments, the drip volume tracker 126 also records and provides to the drip volume manager 124 the duration Δt of the previously executed NPWT cycle and the NPWT pressure setpoint p of the previously executed NPWT cycle. sp(k-1) .

[0086] See still Figure 13 According to some embodiments, memory 116 is shown to include infusion volume manager 124. In some embodiments, infusion volume manager 124 is configured to determine the amount V of infusion fluid to be delivered to wound site 202. instillation In some implementations, the infusion volume manager 124 is configured to base its infusion volume on the actual treatment time (e.g., Δt) and the treatment pressure setpoint p. spV is determined by either the type of NPWT being executed or the reduction factor θ. instillation In some embodiments, the infusion volume manager 124 receives a reduction factor θ from the infusion reduction database 122. In some embodiments, the infusion reduction database 122 includes parameters for T and p. sp A lookup table for various values ​​of θ in different combinations. In some implementations, empirical test results are used to determine various values ​​of θ stored in the drip reduction database 122 and provided to the drip volume manager 124, as described in more detail above.

[0087] In some implementations, the infusion volume manager 124 determines the amount V of infusion fluid to be supplied to the wound 218 for the current infusion cycle k. instillation(k) (e.g., volume, quantity, etc.). In some embodiments, for a first fluid drip cycle, the drip volume manager 124 determines the first amount of drip fluid as V, which is determined by the wound volume manager 121 or received from the user interface manager 128. wound In some implementations, for subsequent fluid infusion cycles, the infusion volume manager 124 determines the amount V of fluid to be supplied to the wound 218 for the current infusion cycle k based on the fluid supplied to the wound 218 for the previous fluid infusion cycle. instillation (k). In some implementations, the infusion volume manager 124 uses the following formula to determine the amount V of infusion fluid to be supplied to the wound 218 for the current infusion cycle k. instillation (k):

[0088] V instillation (k)=V instillation (k-1)-θ·V instillation (k-1)

[0089] According to some implementation schemes, V instillation (k) is the amount of infusion fluid to be supplied to wound 218 for the current fluid infusion cycle k (e.g., in cubic centimeters), θ is the reduction factor, and V instillation (k-1) is the amount of infusion fluid (e.g., in cubic centimeters, in mL, etc.) provided to the wound 218 in response to the previous fluid infusion cycle k-1. In some embodiments, the term θ·V instillation (k-1) is to reduce the previously provided drip fluid volume V instillationThe value of (k-1). In some embodiments, the reduction factor θ is a normalized value (e.g., between 0 and 1). In some embodiments, the reduction factor θ is a percentage value. In some embodiments, the reduction factor θ is selected from the drip reduction database 122 via the drip volume manager 124. In some embodiments, the reduction factor θ is selected or determined based on a previous NPWT cycle. In some embodiments, the NPWT pressure setpoint p is based on a previous NPWT cycle. sp and NPWT in p sp The time Δt provided to the wound 218 under pressure is used to select or determine the reduction factor θ. In some implementations, the following function is used to determine the reduction factor θ:

[0090] θ=f reduc (Δt, p) sp )

[0091] Where θ is the reduction factor, p sp The NPWT pressure setpoint for the previous negative pressure cycle, Δt being the previous NPWT cycle at p sp The duration of NPWT is executed under pressure, and f reduc For θ and p sp The relationship between f and Δt. In some implementations, f reduc This is a function determined based on empirical data. In some implementations, it is based on the NPWT pressure setpoint p. sp V within the time period Δt wound The estimated change (e.g., due to edema, swelling, changes in foam 216, healing, etc.) is used to determine f. reduc .

[0092] In some implementations, the reduction factor θ is selected from a table of values ​​stored in the infusion reduction database 122. For example, the infusion reduction database 122 may include, for example, a table of values ​​stored in the infusion reduction database 122. Figure 14 Table 1400 is shown. Table 1400 includes the pressure setpoint p of the previously provided NPWT. sp Column 1402, and in p sp Column 1406 shows the duration Δt of the NPWT provided under pressure. According to some embodiments, Table 1400 includes column 1404 with values ​​of the reduction factor θ. In some embodiments, the drip volume manager 124 is based on p sp The appropriate value of the reduction coefficient θ is retrieved from Table 1400 in the drip reduction database 122, and Δt is used. For example, as... Figure 14 As shown, according to some implementation schemes, if previously in p spIf NPWT is supplied to wound 218 at a vacuum pressure of 75 mmHg for Δt = 24 hours, the reduction factor θ is 0.05 (or a reduction of 5%). In some embodiments, the infusion volume manager 124 receives the volume / amount V of the previously supplied infusion fluid from the infusion volume tracker 126. instillation (k-1). For example, according to some implementation schemes, if 30 cm is provided to wound 218 during a previous fluid infusion cycle. 3 The dripping fluid, and the reduction factor θ is 0.05 (e.g., for p). sp =75 and Δt=24 hours), then the drip volume manager 124 determines the volume of the drip fluid for the current fluid drip cycle as:

[0093] V instillation (k)=30cm 3 -0.05·30cm 3 =30cm 3 -1.5cm 3 =28.5cm 3 .

[0094] In some embodiments, the infusion volume manager 124 receives an estimated / approximate current volume of the wound 218 from the wound volume manager 121. In some embodiments, the infusion volume manager 124 receives an estimated / approximate current volume of the wound 218 from the user interface manager 128. In some embodiments, the infusion volume manager 124 uses the estimated current volume of the wound 218 to determine a reduction factor θ. In some embodiments, the infusion volume manager 124 uses the following function based on the wound volume V... wound Determine the reduction factor θ:

[0095]

[0096] Where V wound (k) is the estimated volume of wound 218 received from wound volume manager 121 or user interface 106 under the current fluid drip cycle k, V wound (k-1) represents the previously estimated volume of wound 218 under the previous fluid infusion cycle. To connect θ with V wound (k) and V wound (k-1) related functions.

[0097] In some implementations, the NPWT loop may include p at various points in the NPWT loop. sp The changes. Figure 16Graph 1700 illustrates a multi-stage NPWT cycle 1714 according to some embodiments. Graph 1700 also illustrates the negative pressure p provided relative to the actual elapsed time (X-axis) according to some embodiments. sp (Y-axis). In some embodiments, the NPWT loop 1714 includes a first portion 1708, a second portion 1710, and a third portion 1712. According to some embodiments, the first portion 1708 is in p sp =p1 with a duration of 1702 (i.e., Δt1), the second part 1710 at p sp =p2 has a duration of 1704 (i.e., Δt2), and the third part 1712 is at p sp =p3 has a duration of 1706 (i.e., Δt3). In some implementations, p sp The volume increases from the first section 1708 to the second section 1710, and decreases from the second section 1710 to the third section 1712. In some embodiments, the drip volume manager 124 treats each of sections 1708-1712 as a separate section and determines the V for the fluid drip cycle following the NPWT cycle 1714 by determining a reduction factor θ for each section. instillation In some implementations, the duration 1702-1706 is recorded by timer 118. In some implementations, the drip volume manager 124 uses the following formula:

[0098]

[0099] Where n is the number of portions / segments of the NPWT cycle that occur between drip cycle k and drip cycle k-1 (e.g., for...). Figure 16 The example shown is 3), and θ i The reduction factor for each part / segment in the NPWT cycle (e.g., NPWT cycle 1714).

[0100] For NPWT cycle 1714, the above formula simplifies to:

[0101] V instillationn (k)=V instillation (k-1)-V instillation (k-1)(θ1+θ2+θ3)

[0102] Where θ1=f reduc (Δt1, p1), θ2 = f reduc (Δt2, p2), and θ3 = f reduc (Δt3, p3). The function f can be used. reduc Or by using Δt and p spFrom the drip reduction database 122, appropriate reduction factors are selected to determine each of the reduction factors θ1, θ2, and θ3. According to some implementation schemes, the above formula simplifies to:

[0103]

[0104] In some embodiments, n indicates the number of NPWT cycles between fluid dripping cycle k and fluid dripping cycle k-1. In some embodiments, n is based on the NPWT pressure p identified by timer 118. sp The number of changes determines n. In some implementations, the drip volume manager 124 determines the number of portions of the NPWT cycle as:

[0105] n = #p sp changes+1

[0106] Among them #p sp changes is p sp The number of times it varies throughout the entire NPWT cycle. However, if the NPWT cycle is performed at a single pressure (e.g., p), sp If executed at a g / 150 mmHg, then #p sp `changes` is zero, and `n` is one. In some implementations, the number of parts of the NPWT loop indicates the number of reduction factors θ.

[0107] In some implementations, for an NPWT cycle with multiple segments (e.g., NPWT cycle 1714), the drip volume manager 124 treats each segment / part as a separate NPWT cycle. For example, the drip volume manager 124 may determine the reduction factor θ for each part / segment, and the adjusted drip volume V for each part / segment. instillation However, according to some implementations, the "previous" drip fluid volume V used for subsequent partial / segment drips is... instillation (k-1) is set to be equal to the drip fluid V used for the immediately preceding portion / segment. instillation For example, according to some embodiments, for NPWT cycle 1714, segment 1708 has a reduction factor θ1, segment 1710 has a reduction factor θ1, and segment 1712 has a reduction factor θ3. In some embodiments, the drip volume manager 124 uses the following formula:

[0108]

[0109] In some implementation schemes, n is the number of NPWT cycle segments caused by changes in the pressure setpoint, and V instillation(k-1) is the volume of infusion fluid supplied to the wound during the fluid infusion cycle prior to the NPWT cycle, and V instillation (k) is the amount of infusion fluid supplied to the wound during the fluid infusion cycle following the NPWT cycle.

[0110] For example, according to some embodiments, if Δt1 is 24 hours and p1 is 152 mmHg, Δt2 is 24 hours and p2 is 200 mmHg, and Δt3 is 24 hours and p3 is 75 mmHg, then θ1 = 0.08, θ2 = 0.10, and θ3 = 0.05, as determined with reference to Table 1400. According to some embodiments, for illustrative purposes, it is assumed that the previously provided drip volume V... instillation If (k-1) is 100 mL, then the drip volume to be provided for the fluid drip cycle after NPWT cycle 1714 can be determined as follows:

[0111] V instillation (k)=(V instillaion (k-1))(1-θ1)(1-θ2)(1-θ3

[0112] =100mL(1-0.08)(1-0.10)(1-0.05)=100mL(0.7866)=78.66mL.

[0113] Alternatively, according to some implementation schemes, the dripping fluid volume V can be determined using the following formula. instillation (k):

[0114]

[0115] It becomes:

[0116] V instillation (k)=100mL(1-(0.08+0.10+0.05))=100mL(0.77)=77mL.

[0117] In some implementations, for pressure setpoint p sp The changes cause NPWT cycles with multiple parts, and the average pressure across the entire NPWT cycle is determined. For example, according to some implementation schemes, for such... Figure 16 The NPWT cycle 1714 shown has an average setpoint p. avg It can be determined as:

[0118]

[0119] It can be summarized as follows:

[0120]

[0121] In some implementations, the drip volume V for the fluid dripping cycle following NPWT cycle 1714 can then be determined using the following formula. instillation (k):

[0122] V instillation (k)=(V instillation (k-1))(1-θ avg )

[0123] Where θ avg For the total Δt (e.g., Δt1+Δt2+Δt3) and p based on NPWT cycle 1714 avg To select or determine the reduction factor.

[0124] In some implementation schemes, p avg To provide each specific p sp The weighted average of time quantities. For example, p can be determined using the following formula. avg :

[0125]

[0126] Or more generally:

[0127]

[0128] Where Δt total Where n is the total time of the NPWT cycle, and n is the number of parts / segments of the NPWT cycle. Then the drip volume manager 124 can use this p avg The value of θ is used to determine or select the reduction factor.

[0129] In some implementations, the drip volume manager 124 determines the V for an upcoming fluid drip cycle. instillation (k), and provides V to the control signal manager 130 instillation (k) (also shown as V(k)). In some implementations, the drip volume manager 124 also provides V to the drip volume tracker 126. instillation The value of (k) is used to determine V. instillation The future value of (k). In some implementations, the control signal manager 130 receives V instillation The value of (k) is determined, and the control signal for pump 142 is determined to deliver V during the fluid dripping cycle. instillation The value of (k) is delivered / provided to wound 218. In some embodiments, the control signal manager 130 adjusts the operation of pump 142 and / or the pump's drip / fluid delivery to provide V to wound site 202. instillation (k) Drip fluid.

[0130] In some implementations, the drip volume manager 124 provides V to the user interface manager 128. instillation The value of (k). In some embodiments, the user interface manager 128 determines the display signals and provides these display signals 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 V to the user. instillation The value of (k). In some embodiments, this is beneficial for providing the user with an indication of how much infusion fluid is placed in the infusion fluid reservoir 204. For example, in some embodiments, the pump 142 is configured to deliver all the infusion fluid present in the infusion fluid reservoir 204 to the wound site 202. If the user interface manager 128 causes the user interface 106 to display V instillation (k) means that the user knows how much drip fluid to provide to the drip fluid reservoir 204 for the pump 142 to deliver to the wound site 202.

[0131] In some embodiments, the user can replace the foam 216 during the dressing change phase. In some embodiments, the user interface 106 is configured to receive user input indicating that the foam 216 has been replaced with fresh foam 216. In some embodiments, the user interface 106 is configured to provide an indication of foam 216 replacement 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 after the foam 216 has been replaced. wound In some implementations, the user interface manager 128 prompts the user interface 106 to input the wound volume V at the user interface 106. wound In some implementations, the infusion volume manager 124 receives V from at least one of the wound volume manager 121 and the user interface manager 128. wound And determine the initial drip volume V instillation (k). According to some embodiments, replacing foam 216 "resets" the infusion volume manager 124, so that the reduction in infusion volume calculated since the previous dressing change is no longer relevant. However, the infusion volume manager 124 may still account for volume changes due to wound healing (e.g., V). wound (changes), but since foam 216 was replaced, due to changes in the volume of the drip fluid caused by foam compression and clogging (e.g., reduced C). foam This is no longer relevant. In some implementations, the drip volume manager 124 essentially "restarts" in response to the replacement of foam 216.

[0132] In some embodiments, the drip volume manager 124 takes into account the selected soaking time of the foam 216. For example, allowing the foam 216 to soak for a period of time after delivery of the drip fluid and before application of negative pressure can reduce the effects of compression deformation of the foam 216. In some embodiments, the drip volume manager 124 is based on the soaking time Δt. soak To modify (e.g., reduce) the reduction factor θ. In some implementations, the drip volume manager 124 determines the amount of soaking time Δt taken into account. soak Adjusted reduction factor θ adj In some implementations, the drip volume manager 124 uses the following formula:

[0133] θ adj =θ-Δθ soak

[0134] Where Δθ soak Based on Δt soak The determined adjustment amount (e.g., Δθ) soak =f(Δt) soak In some implementations, the longer the foam 216 is allowed to soak, the greater the Δθ. soak The larger the value, and therefore the adjusted reduction factor θ adj Reduce. In some implementations, the soaking time Δt soak It is defined as the amount of time after the infusion fluid has been provided to the wound site 202 and before negative pressure is aspirated at the wound site 202. In some embodiments, the soaking time Δt soak Input is made by the user through user interface 106.

[0135] Now for reference Figure 17 Graph 1800 illustrates the operation of controller 110 over time according to some embodiments. Graph 1800 illustrates several NPWT cycles according to some embodiments, shown as NPWT cycle 1802, NPWT cycle 1804, and NPWT cycle 1806. According to some embodiments, a fluid dripping cycle precedes the NPWT cycle, shown as dripping cycle 1814, dripping cycle 1816, and dripping cycle 1818. According to some embodiments, NPWT cycle 1802 is shown to be performed for duration 1808 at a vacuum pressure of 75 mmHg, NPWT cycle 1804 is shown to be performed for duration 1810 at a vacuum pressure of 75 mmHg, and NPWT cycle 1806 is shown to be performed for duration 1812 at a vacuum pressure of 150 mmHg. In some embodiments, the dripping fluid volume V instillation (k-3) is provided under drip cycle 1814, V instillation (k-2) is provided under drip cycle 1816, and V instillation(k-1) is provided under drip cycle 1818. According to some implementations, in order to determine V of the current drip cycle 1820... instillatin (k) The controller 110 selects an appropriate reduction factor θ from the drip reduction database 122 based on the vacuum pressure (i.e., 150 mmHg) and duration (i.e., duration 1812) of the previously executed NPWT cycle (i.e., NPWT cycle 1806). According to some embodiments, the controller 110 then determines V using the following formula. instillation (k):

[0136] V instillation (k)=(V instillation (k))(1-θ)

[0137] According to some implementation schemes, after performing 1820 drip cycles, V is then... instillation (k) stored as V instillation (k-1) is used for future infusion cycles. Similarly, according to some implementations, V is used for infusion cycle 1818. instillation (k-1) Based on NPWT cycle 1804 (i.e., duration 1810, vacuum pressure 75 mmHg) and V insiillation (k-2) is used to determine and for V in drip cycle 1816 instillation (k-2) Based on NPWT cycle 1802 (i.e., duration 1808, vacuum pressure 75 mmHg) and V instillation (k-3) etc. are used to determine this.

[0138] See now Figure 18 Graph 1900 illustrates the change in the infusion volume delivered to the wound (e.g., wound 218) over time according to some embodiments. According to some embodiments, the Y-axis of graph 1900 indicates the volume of infusion fluid delivered to the wound site 202 for the corresponding infusion cycle (X-axis). As shown in graph 1900, the decrease over time is non-linear because each volume of the infusion fluid is determined based on previous values ​​of the infusion fluid provided. In some embodiments, graph 1900 may be linear if the controller 110 reduces the infusion volume for each infusion cycle by a standard amount.

[0139] Control Algorithm Method

[0140] See now Figure 15This illustrates a process 1500, according to some embodiments, for determining the amount of infusion fluid to be delivered to a wound for NPWT. In some embodiments, process 1500 is performed by a controller 110. In some embodiments, process 1500 is performed by one or more components of the controller 110 (e.g., by an infusion volume manager 124).

[0141] According to some implementation schemes, process 1500 includes receiving a treatment pressure setpoint p. sp (Step 1502). In some implementations, the treatment pressure setpoint p sp This refers to the vacuum pressure setpoint for the NPWT cycle. In some implementations, the treatment pressure setpoint p sp 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 the timer 118 for monitoring the amount of time that NPWT is delivered to the wound at the treatment pressure setpoint.

[0142] According to some embodiments, process 1500 includes infusing a 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 a user interface 106. In some embodiments, the wound volume is estimated by a wound volume manager 121. In some embodiments, an infusion volume manager 124 is configured to receive the estimated wound volume to determine the initial infusion volume. In some embodiments, the infusion volume manager 124 uses the wound volume and a relationship between the wound volume and the desired 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, a 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 the initial volume of infusion fluid to the wound site 202.

[0143] According to some implementations, process 1500 includes monitoring the amount of NPWT time actually elapsed (step 1506). In some implementations, the amount of time elapsed is monitored by timer 118. In some implementations, the amount of time elapsed is the amount of time that NPWT has been performed at the treatment pressure setpoint received in step 1502. In some implementations, the monitored elapsed time is provided to infusion volume manager 124.

[0144] According to some embodiments, process 1500 includes determining a second infusion volume and providing the second infusion volume of fluid to the wound area (step 1508). In some embodiments, the new or adjusted infusion volume is reduced 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 time elapsed to provide the NPWT at the treatment pressure setpoint. In some embodiments, step 1508 is performed by an infusion volume manager 124. In some embodiments, step 1508 includes any function of the infusion volume manager 124 to determine V instillation (k).

[0145] According to some implementations, process 1500 includes replacing the first drip volume value with a second drip volume value (step 1510). In some implementations, in response to the completion of step 1508, the first drip volume value is replaced by the most recently determined second drip volume value. In some implementations, step 1510 is performed by drip volume tracker 126.

[0146] According to some implementations, process 1500 includes repeating steps 1502-1510 until treatment is complete (step 1512). In some implementations, step 1512 is performed by controller 110. In some implementations, steps 1502-1510 are repeated until NPWT is complete, or until the user changes the wound dressing.

[0147] Configuration of exemplary implementation

[0148] As used herein, the terms “about,” “approximately,” “substantially,” and similar terms are intended to have a broad meaning consistent with common and generally accepted usage by one of ordinary skill in the art to which the subject matter of this disclosure pertains. Those skilled in the art who read this disclosure will understand that these terms are intended to allow for the description and claim of certain features without limiting the scope of those features to the precise numerical ranges provided. Therefore, these terms should be interpreted as indicating non-substantial or irrelevant modifications or alterations to the subject matter described and protected by the claims, and are considered to be within the scope of this disclosure as set forth in the appended claims.

[0149] It should be noted that the term “exemplary” and its variations, as used herein to describe various implementations, are intended to indicate possible examples, representations or illustrations of possible implementations (and such terms are not intended to imply that such implementations are necessarily special or superlative examples).

[0150] The hardware and data processing components described herein for implementing various processes, operations, exemplary logic, logic blocks, modules, and circuits can be implemented or executed using general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor can be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. The processor can also be implemented as a combination of computing devices, such 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. In some embodiments, specific processes and methods may be executed by circuitry specific to a given function. Memory (e.g., memory, memory cell, storage device) may include one or more means (e.g., RAM, ROM, flash memory, hard disk storage devices) for storing data and / or for performing or facilitating the various processes, layers, and modules described herein. The memory may be or include volatile or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein. According to an exemplary embodiment, the memory is communicatively connected to a processor via processing circuitry and includes computer code for (e.g., via processing circuitry or the processor) performing one or more of the processes described herein.

[0151] This disclosure contemplates methods, systems, and program products on any machine-readable medium for implementing various operations. Embodiments of this disclosure may be implemented using existing computer processors, or by a dedicated computer processor of a suitable system incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of this disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available medium accessible by a general-purpose or special-purpose computer or other machine having a processor. By way of example, such machine-readable media may include RAM, ROM, EPROM, EEPROM, or other optical disk storage devices, magnetic disk storage devices, or other magnetic storage devices, 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 accessible by a general-purpose or special-purpose computer or other machine having 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, special-purpose computer, or special-purpose processor to perform a particular function or group of functions.

Claims

1. A treatment system comprising: An infusion system configured to provide infusion fluid to a wound dressing configured to be placed on a wound; The controller is configured to: Provide a first amount of drip fluid for the first drip cycle; A second amount of drip fluid is determined for the second drip cycle based on the first amount and the reduction factor, wherein the second amount of drip fluid is less than the first amount of drip fluid; as well as Adjust the operation of the infusion system to provide the second amount of infusion fluid to the wound. The reduction factor is determined based on the amount of compression of the wound dressing over a certain period of time.

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

3. The treatment system of claim 1, wherein the wound dressing comprises one or more foam blocks.

4. The treatment system of claim 1, wherein 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 the first amount of infusion fluid.

5. The treatment system of claim 1, wherein the controller is configured to determine the second amount of infusion fluid for the second infusion cycle by determining a reduction amount based on the reduction factor and the first amount.

6. The treatment system according to claim 5, wherein the second quantity is the difference between the first quantity and the first quantity multiplied by the reduction factor.

7. The treatment system according to claim 1, wherein the reduction factor is a normalized value.

8. A treatment device configured to provide fluid to a wound and generate negative pressure at the wound for negative pressure wound therapy, the treatment device comprising: The controller is configured to: The reduction factor is selected based on the amount of compression of the wound dressing over a certain period of time; The reduction value of the fluid volume supplied to the wound is determined based on a previous value of the fluid volume supplied to the wound and the reduction factor; as well as The treatment device provides the reduced fluid volume to the wound; The fluid volume of the reduced value is less than the fluid volume of the previous value provided to the wound.

9. The treatment device according to claim 8, wherein the reduction factor is a percentage value.

10. The treatment device of claim 9, wherein the reduction value of the fluid volume is determined by subtracting the percentage value from a previous value of the fluid volume.

11. The treatment device of claim 9, wherein the controller is further configured to monitor the negative pressure at the wound site and the actual treatment time.

12. The treatment device of claim 11, wherein if the negative pressure monitored at the wound site is between 70 mmHg and 80 mmHg, and the actual treatment time is a predetermined amount of time, the percentage value selectable by the controller is between three percent and six percent.

13. The treatment device of claim 11, wherein if the negative pressure monitored at the wound site is between 145 mmHg and 155 mmHg, and the actual treatment time is a predetermined amount of time, the percentage value selectable by the controller is between seven percent and nine percent.

14. The treatment device of claim 11, wherein if the negative pressure monitored at the wound site is between 195 mmHg and 205 mmHg, and the actual treatment time is a predetermined amount of time, the percentage value selectable by the controller is between nine percent and eleven percent.

15. A treatment device configured to provide a second amount of infused fluid to a wound and generate negative pressure at the wound for negative pressure wound therapy, the treatment device comprising: The controller is configured to: Based on the previous pressure setting and the time for providing negative pressure wound therapy at the previous pressure setting, a reduction factor is selected from a set of reduction factors; The second amount of infusion fluid provided to the wound is determined based on the first amount of infusion fluid provided to the wound and the reduction factor; as well as The treatment device provides the second amount of drip fluid to the wound; The second amount of infusion fluid is less than the first amount of infusion fluid provided to the wound.

16. The treatment device of claim 15, wherein the set of reduction factors is stored in a table of an accessible database by the controller.

17. The treatment device according to claim 15, wherein the reduction factor is a percentage value.

18. The treatment device of claim 17, wherein the second amount of infusion fluid is determined by reducing the percentage value of the first amount of infusion fluid.

19. The treatment device of claim 15, wherein the controller is further configured to monitor the negative pressure at the wound site and the actual treatment time.

20. The treatment device according to claim 15, wherein the reduction factor is a normalized value.

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