Wound therapy system with wound volume estimation

Abstract

The volume of the wound is estimated using the dynamic pressure response measured during infusion of fluid into the wound using a negative pressure wound therapy system. The previously estimated wound volume may be used to detect and prevent overfilling of the wound with fluid during future infusion events. For example, real-time pressure measurements can be compared to model data representing the expected pressure in a wound having a volume equal to the previously estimated wound volume, and infusion is stopped if the observed pressure differs from the expected pressure. The total volume of fluid infused into the wound can be compared to the previously estimated wound volume to prevent overfilling. The wound volume estimated based on the infusion event can also be compared to wound volumes estimated using other methods to provide a more reliable wound volume estimate.

Description

Technical Field

[0001] The present disclosure generally relates to wound therapy systems, and more particularly to wound therapy systems configured to estimate the volume of a wound site.

Background Art

[0002] Negative pressure wound therapy (NPWT) is a type of wound therapy that involves applying negative pressure to a treatment site to promote wound healing. Recent advances in wound healing with NPWT involve applying topical fluid to the wound to act in combination with NPWT. However, it can be difficult to determine the appropriate volume of drip solution to deliver to the wound. Additionally, it can be difficult to accurately monitor and track the progress of wound healing over time. Therefore, it is advantageous to provide a system and method that enables an accurate and reliable estimate of the available space at the wound site where the drip solution can be delivered and an estimate of the progress of healing of the wound site over time. Advantageously, such a system and method additionally enables such volume determination to be automatically performed by a controller, can be performed at any stage during an NPWT treatment, does not require additional time and / or steps for performing that may be required in a typical NPWT treatment, enables detection and / or prevention of overfilling during a fluid drip cycle, and / or can account for changes in the type or size of the removal fluid canister used over the course of an NPWT treatment.

Summary of the Invention

[0003] In one embodiment of the present disclosure, the method includes operably connecting a first end of a fluid tube to a fluid canister and pump of a therapy device, and operably connecting a second end of the fluid tube to a wound dressing applied to a wound site. The pump is operated until a predetermined first negative pressure is detected. A first volume of fluid is infused into the wound site until a first predetermined target pressure is detected. The pressure is monitored during the infusion of the first volume of fluid into the wound site. The volume of the first volume of fluid infused into the wound site is determined using pressure measurements obtained from the pressure monitored during the infusion of the first volume of fluid into the wound site.

[0004] According to some embodiments, determining the volume of a first amount of fluid infused into a wound site involves comparing acquired pressure measurements with model pressure decay data. According to some embodiments, the model pressure decay data represents the pressure decay within a container as a predetermined amount of fluid is infused into a container having a known volume. According to some embodiments, the model pressure decay data includes pressure decay data for a plurality of containers having known volumes.

[0005] According to some embodiments, a determined volume of a first amount of fluid infused into the wound site is stored. According to some embodiments, a first predetermined target pressure is approximately 0 mmHg. According to some embodiments, the pump is operated until a predetermined second negative pressure is detected. According to some embodiments, a second amount of fluid is infused into the wound site until a second predetermined target pressure is detected. According to some embodiments, the pressure is monitored during the infusion of the second amount of fluid into the wound site.

[0006] According to some embodiments, the volume of a second amount of fluid infused into the wound site is determined using pressure measurements obtained from the pressure monitored during the infusion of the second amount of fluid into the wound site. According to some embodiments, the second predetermined target pressure is approximately 0 mmHg.

[0007] According to some embodiments, a first volume of fluid is infused into the wound site at a predetermined flow rate. According to some embodiments, a second volume of fluid is infused into the wound site at a predetermined flow rate. According to some embodiments, a determined volume of the second volume of fluid infused into the wound site is stored in memory. According to some embodiments, the rate of wound healing is determined by comparing the stored first volume with the stored second volume.

[0008] In one implementation of the present disclosure, a method for preventing overfilling of a wound site with fluid includes operably connecting a first end of a fluid tube to a fluid canister and pump of a therapy device, and operably connecting a second end of the fluid tube to a wound dressing applied to the wound site. The pump is operated to achieve a predetermined first negative pressure. The fluid is infused into the wound site. The pressure during the infusion of the fluid into the wound site is monitored. The infusion of the fluid into the wound site is stopped in response to the detection of a first predetermined target pressure.

[0009] According to some embodiments, a first predetermined target pressure is 0 mmHg. According to some embodiments, the volume of the wound site is estimated before the fluid is infused into the wound site. According to some embodiments, model pressure decay data is acquired, which represents the pressure decay in a container as various amounts of fluid are infused into a container having a volume equal to the estimated volume of the wound site. According to some embodiments, monitoring the pressure includes acquiring pressure measurements. According to some embodiments, the acquired pressure measurements are compared in real time with the model pressure decay data. According to some embodiments, an alarm is generated if the measured pressure does not correspond to the model pressure decay data.

[0010] According to some embodiments, the volume of fluid infused into the wound site is determined. According to some embodiments, the volume of fluid infused into the wound site is determined using pressure measurements obtained from the pressure monitored during the infusion of fluid into the wound site. According to some embodiments, determining the volume of fluid infused into the wound site involves comparing the obtained pressure measurements with model pressure decay data.

[0011] According to some embodiments, the second predetermined pressure is 0 mmHg. According to some embodiments, the estimated volume of the wound site is compared with the determined volume of the fluid infused into the wound site. According to some embodiments, an alarm is generated if the estimated volume of the wound site is not substantially the same as the determined volume of the fluid infused into the wound site.

[0012] In one implementation of the present disclosure, the wound therapy system includes a pump, a wound dressing configured to be applied to a wound site, a fluid tube for fluidizing the pump to the wound dressing, and a controller. The controller is configured to monitor the pressure during the infusion of fluid into the wound site and to determine the volume of fluid infused into the wound site using pressure measurements obtained from the monitored pressure during the infusion of fluid into the wound site.

[0013] According to some embodiments, the controller is configured to determine the volume of fluid infused into the wound by comparing acquired pressure measurements with model pressure decay data. According to some embodiments, the controller is configured to store the determined volume of fluid infused into the wound site. According to some embodiments, the controller is configured to determine the volume of fluid infused into the wound site for each of one or more infusion events that occur during treatment of the wound site. According to some embodiments, the controller is configured to store each of the determined volumes. According to some embodiments, the controller is configured to monitor the healing of the wound site based on the stored and determined volumes.

[0014] According to some embodiments, the wound therapy system further includes a source of intravenous fluid. A controller is further configured to operate a pump to infuse fluid into the wound site. According to some embodiments, the controller is configured to stop infusing fluid into the wound site when a first predetermined pressure is detected. According to some embodiments, the controller is configured to stop operating the pump when a pressure of substantially 0 mmHg is detected. According to some embodiments, the controller is further configured to operate the pump to remove air from the wound site.

[0015] According to some embodiments, the controller is further configured to operate the pump to remove air from the wound site and achieve a predetermined negative pressure. When it detects that the pressure is equal to the predetermined negative pressure, the controller is configured to operate the pump to infuse fluid into the wound site. The controller is configured to stop infusing fluid into the wound site when it detects that the measured pressure is equal to a predetermined target pressure.

[0016] In one implementation of the present disclosure, the wound therapy system includes a pump, a wound dressing configured to be applied to a wound site, a fluid tube for fluidizing the pump to the wound dressing, a source of infusion fluid, and a controller. The controller is configured to operate the pump to infuse the infusion fluid into the wound site and to monitor the pressure during the infusion of the fluid into the wound site. The controller is configured to stop the pump in response to the detection of a first predetermined pressure.

[0017] According to some embodiments, a predetermined pressure is 0 mmHg. According to some embodiments, the controller is configured to obtain an estimated volume of the wound site before operating the pump to infuse fluid into the wound site. According to some embodiments, the controller is configured to obtain pressure measurements based on the pressure monitored while the pump is operating to infuse fluid into the wound site. According to some embodiments, the controller is configured to obtain model pressure decay data, which represents the pressure decay in a container as the fluid is infused into a container having a volume equal to the estimated volume of the wound site. According to some embodiments, the controller is further configured to compare the pressure measurements with the model pressure decay data in real time.

[0018] According to some embodiments, an alarm is generated if the measured pressure does not correspond to the model pressure decay data. According to some embodiments, the estimated volume of the wound site is obtained by the controller by operating a pump to remove air from the wound site.

[0019] According to some embodiments, the controller is further configured to operate the pump to remove air from the wound site and to monitor the pressure as the air is removed from the wound site. The controller is further configured to stop the pump when a predetermined negative pressure is detected. According to some embodiments, the controller is configured to operate the pump to infuse an intravenous fluid into the wound site after a predetermined negative pressure has been detected.

[0020] According to some embodiments, the controller is configured to estimate the volume of fluid infused into the wound site using pressure measurements obtained from the pressure monitored during fluid infusion into the wound site. According to some embodiments, the controller is configured to estimate the volume of fluid infused into the wound site by comparing the obtained pressure measurements with model pressure decay data. According to some embodiments, the model pressure decay data represents the pressure decay within a container during fluid infusion into a container of known volume.

[0021] According to some embodiments, the controller is configured to obtain an estimate of the volume of the wound site. According to some embodiments, the estimated volume of the wound site is compared to a determined volume of fluid infused into the wound site. According to some embodiments, an alarm is generated if the estimated volume of the wound site is not substantially the same as the determined volume of fluid infused into the wound site.

[0022] Those skilled in the art will understand that the outline of the invention is merely illustrative and not intended to limit it in any way. Other aspects, inventive features, and advantages of the apparatus and / or process described herein and defined solely by the claims will become apparent in the detailed description described herein and to be interpreted in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0023] [Figure 1] Figure 1 is a block diagram of a negative pressure wound therapy system, according to an exemplary embodiment, which includes a therapy device connected to a wound dressing via a tube.

[0024] [Figure 2] Figure 2 is a block diagram showing in more detail the negative pressure wound therapy system of Figure 1 according to an exemplary embodiment.

[0025] [Figure 3]FIG. 3 is a block diagram showing in more detail the negative pressure circuit, the removal fluid canister circuit, and the wound site circuit of the negative pressure wound therapy system of FIG. 1, according to an exemplary embodiment.

[0026] [Figure 4] FIG. 4 is a block diagram showing a negative pressure wound therapy system, according to an exemplary embodiment.

[0027] [Figure 5] FIG. 5 is a flowchart of a method of using a negative pressure wound therapy system, according to an exemplary embodiment.

[0028] [Figure 6] FIG. 6 is a flowchart of a process for monitoring the healing progress of a wound site over time, according to an exemplary embodiment.

[0029] [Figure 7] FIG. 7 is a flowchart of a method of using a negative pressure wound therapy system, according to an exemplary embodiment.

[0030] [Figure 8] FIG. 8 is a flowchart of a method of using a negative pressure wound therapy system, according to an exemplary embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

[0031] Overview Generally, referring to the figures, the wound therapy system is shown by various exemplary embodiments. The wound therapy system may include a therapy device and a wound dressing. The therapy device may include an infusion canister, a removal fluid canister, a valve, a pneumatic pump, an infusion pump, and a controller. The wound dressing can be applied to the patient's skin surrounding the wound. The therapy device may be configured to provide negative pressure wound therapy (NPWT) by delivering an infusion to the wound and maintaining the wound at negative pressure. The components of the wound therapy device, wound dressing, and wound site form a negative pressure circuit.

[0032] The controller may be configured to operate the pneumatic pump, infusion pump, and / or other controllable components of the therapy device. According to some embodiments, in which an NPWT treatment provided using the NPWT system includes the infusion of an infusion fluid into a wound site, the controller may be configured to estimate the volume of the wound site and / or the volume of the infusion fluid delivered to the wound site based on a comparison of the dynamic pressure response observed as the fluid is infused into the wound site with model pressure response data. Since the dynamic pressure response is observed concurrently with the infusion of the fluid into the wound site, the systems and methods described herein are configured to allow the controller to estimate the wound site volume without requiring additional steps and / or time that may otherwise be required to provide an infusion therapy treatment using an NPWT system.

[0033] According to some embodiments, wound site volume estimates based on dynamic pressure responses observed during fluid infusion can be used to compare wound site volume estimates obtained using any number of other methods, or to compare with wound site volume estimates obtained using any number of other methods, to provide a more reliable wound site volume estimate to the NPWT system. For example, in some embodiments, the controller can compare the wound site volume estimated based on dynamic pressure responses observed during fluid infusion with the wound site volume estimated based on a comparison of dynamic pressure responses observed during negative pressure purging in the entire and / or selected portion of the negative pressure circuit.

[0034] In various embodiments, the controller may be additionally or alternatively configured to prevent and / or detect overfilling of the wound site during infusion of the infusion fluid. According to some such embodiments, the controller can prevent overfilling of the wound site with the infusion fluid by using a previously obtained wound site volume estimate (e.g., a wound site volume estimate estimated during a previous infusion of fluid to the wound site, a wound site volume estimate based on a comparison of dynamic pressure responses observed during negative pressure purging from a negative pressure circuit) as a backstop value compared to the volume of the amount of fluid infused to the wound site. In some embodiments, the previously obtained wound site volume estimate may be additionally or alternatively used to identify a model pressure decay curve that represents the expected dynamic pressure response during infusion of the infusion fluid to the wound site in order to achieve a predetermined target pressure, measured at the wound site in one or more of the following locations: in the tubing fluid connecting the wound site to the therapy device, in the removal fluid canister, or in the therapy device. In such embodiments, the dynamic pressure response at the wound site is monitored in real time and compared with a model pressure decay curve. The difference between the monitored pressure and the predicted pressure based on the model decay curve is used to alert the controller to potential overfilling conditions that may require attention.

[0035] In some embodiments, additionally or alternatively, the controller may estimate and monitor the wound site volume multiple times during wound treatment, and the controller determines the progress of wound healing based on the estimated changes in wound site volume throughout the course of the NPWT treatment. By monitoring the progress of wound healing, the controller may be configured to alert the user if wound healing does not progress as intended or expected. As understood, in some embodiments, monitoring the change in estimated wound site volume over time can provide the controller with additionally advantageous, more accurate values ​​that enable the controller to more accurately detect and / or prevent overfilling of the wound site with infusion fluid. These and other features of the wound therapy system are described in detail below.

[0036] Wound healing system Referring here to Figure 1, an exemplary embodiment of a negative pressure wound therapy (NPWT) system 100 is shown. The NPWT system 100 is shown to include a therapy device 102 fluidly connected to a wound dressing 112 via tubes 108 and 110. According to various embodiments, the wound dressing 112 may be placed on or within the wound site 114 and adhered to or sealed to the patient's skin 116 surrounding the wound site 114 using a drape layer 117. Several examples of wound dressings 112 that can be used in combination with the NPWT system 100 are described in detail in U.S. Patent No. 7,651,484 granted on 26 January 2010, U.S. Patent No. 8,394,081 granted on 12 March 2013, and U.S. Patent Application No. 14 / 087,418 filed on 22 November 2013. The entire disclosures of each of these patents and patent applications are incorporated herein by reference.

[0037] As shown in the block diagram of Figure 2, the therapy device 102 generally includes a pneumatic pump 120, an infusion pump 122, a filter 128, and a controller 118. The pneumatic pump 120 may be fluid-coupled to a removal fluid canister 106 (for example, via a conduit 136) and may be configured to evacuate the canister 106 by pressurizing air from the canister 106. In some embodiments, the pneumatic pump 120 is configured to operate in both forward and reverse directions. For example, the pneumatic pump 120 can operate in the forward direction to pressurize air from the canister 106 and reduce the pressure in the canister 106. The pneumatic pump 120 can operate in the reverse direction to pressurize air into the canister 106 and increase the pressure in the canister 106. The pneumatic pump 120 can be controlled by the controller 118, which is described in more detail below.

[0038] Therapy device 102 may be configured to provide negative pressure wound therapy by reducing the pressure at the wound site 114. Therapy device 102 can create a vacuum (relative to atmospheric pressure) at the wound site 114 by removing wound exudate, air, and other fluids from the wound site 114. Wound exudate may include fluids that leave the patient's circulatory system and enter the area of ​​lesion or inflammation. For example, wound exudate may include water, as well as soluble solutes such as blood, plasma proteins, leukocytes, platelets, and erythrocytes. Other fluids 121 removed from the wound site 114 may include intravenous fluids 105 previously delivered to the wound site 114. Intravenous fluids 105 may include, for example, lavage solutions, prescribed fluids, drug solutions, antibiotic solutions, or any other type of fluid that can be delivered to the wound site 114 during wound treatment. The infusion solution 105 is held in an infusion solution canister 104 and can be controlledly dispensed to the wound site 114 via a tube 108. In some embodiments, the infusion solution canister 104 is detachable from the therapy device 102 so that the canister 104 can be refilled and replaced as needed.

[0039] The drip pump 122 can be fluidly connected to the drip fluid canister 104 and wound dressing 112 via the drip tube 108. The drip pump 122 can be operated to deliver the drip fluid 105 to the wound dressing 112 and wound site 114 by pressurizing the drip fluid 105 through the drip tube 108. The drip pump 122 can be controlled by a controller 118, which is described in more detail below. According to some embodiments, the drip pump 122 may be defined by all or part of a pneumatic pump 120.

[0040] The filter 128 may be positioned between the removal fluid canister 106 and the pneumatic pump 120 (for example, along the conduit 136) so that the air pressurized from the canister 106 passes through the filter 128. The filter 128 may be configured to prevent liquid or solid particles from entering the conduit 136 and reaching the pneumatic pump 120. The filter 128 may include a bacterial filter that is hydrophobic and / or lipophilic so that, for example, aqueous and / or oily liquids bead up on the surface of the filter 128. The pneumatic pump 120 may be configured to provide sufficient airflow through the filter 128 so that the pressure drop across the filter 128 is not substantial (for example, so that the pressure drop does not substantially interfere with the application of negative pressure from the therapy device 102 to the wound site 114).

[0041] The fluid removal canister 106 may be a component of the therapy device 102 configured to collect wound exudate and other fluids 121 removed from the wound site 114. In some embodiments, the fluid removal canister 106 is removable from the therapy device 102 to allow the canister 106 to be emptied and replaced as needed. The lower portion of the canister 106 may be filled with wound exudate and other fluids 107 removed from the wound site 114, and the upper portion of the canister 106 may be filled with air. The therapy device 102 may be configured to create a vacuum inside the canister 106 by pressurizing air from the canister 106. The reduced pressure inside the canister 106 can be transferred to the wound dressing 112 and the wound site 114 via the tube 110.

[0042] As shown in Figure 1, a tube valve 111 (e.g., spring-loaded, duckbill, check valve, etc.) configured to prevent fluid flow from the removal fluid canister 106 to the wound site 114 may be positioned along the tube 110 between the removal fluid canister 106 and the wound site 114.

[0043] Referring to the block diagram in Figure 3, the removal fluid canister 106, the tube 110, the conduit 136 extending between the pneumatic pump 120 and the removal fluid canister 106, and the wound site 114 are fluid-connected to define a negative pressure circuit 200. As will be described in more detail below, the volumes of the tube 110 and the conduit 136 define known volumes that can be easily subtracted from or included in the calculation of the volume(s) of the wound site 114. As shown in Figure 2, according to various embodiments, a vent 132 may be provided, and the negative pressure circuit 200 may be evacuated through the vent 132.

[0044] As further illustrated with reference to Figure 8, according to some embodiments, it may be desirable to compare the volume estimated using any of the methods described herein with a volume estimate obtained using other methods and / or from other sources, for example, a volume estimated based on measurements taken during a negative pressure circuit drawdown, as described in related concurrently pending U.S. Provisional Patent Application No. 62 / 714,229, filed August 3, 2018, titled WOUND THERAPY SYSTEM WITH WOUND VOLUME ESTIMATION, whose entire disclosure is incorporated herein by reference. Accordingly, according to various embodiments, as shown in Figure 4, the NPWT system 100 may optionally include one or more features configured to enable the use of the NPWT system 100 to estimate volume using any number of other methods, in addition to the various methods for estimating volume during fluid dripping described herein.

[0045] For example, as shown in Figure 4, the NPWT system 100 may include features similar to those described with reference to the various systems described in the related concurrently pending U.S. Provisional Patent Application No. 62 / 714,229. In particular, according to some embodiments, the tube valve 111 described with reference to the embodiment in Figure 1 may be modified, and the tube valve 111' in the embodiment in Figure 4 is configured to selectively allow and prevent fluid flow between the removal fluid canister 106 and the wound site 114, thereby enabling the negative pressure circuit 200 to be selectively fluid-divided into a removal fluid canister circuit (i.e., the portion of the negative pressure circuit located upstream of the tube valve 111') and a wound site circuit (i.e., the portion of the negative pressure circuit located downstream of the tube valve 111'). Referring again to Figure 4, according to some embodiments, the NPWT system 100 may also be provided with a calibrated leak system 113 configured to selectively control and measure the airflow between the tube 110 and the surrounding environment surrounding the therapy device 102. According to various embodiments, the calibrated leak system 113 can be selectively opened to allow airflow into the tube 110 at a known predetermined speed.

[0046] As shown in the block diagram of Figure 2, according to various embodiments, the controller 118 may be configured to operate various components of the therapy device 102. In particular, according to various embodiments, as described in more detail below, the controller 118 may be configured to control various components of the NPWT system 100 to perform one or more volume determination procedures, through which, for example, the estimated volume of the wound site 114 may be determined, and the healing progress of the wound site may be tracked. According to various embodiments, the controller 118 may be configured so that these procedures can be performed with minimal user intervention and / or input.

[0047] According to various embodiments, the NPWT system 100 may include various sensors. For example, in some embodiments, one or more pressure sensors 115 may be located in one or more of the following locations: in the line within the tube 110, in the wound dressing 112, in the fluid removal canister 106, in the therapy device 102, in the pump 120, etc., to enable measurement of pressure in one or more of the following locations: in the fluid removal canister 106, in the tube 110, and / or in the wound site 114. Pressure readings recorded by the pressure sensor(s) 115 may be transmitted to the controller 118. According to various embodiments, the controller 118 may use the pressure readings from the pressure sensor(s) 115 as input to various pressure testing and control operations performed by the controller 118.

[0048] In some embodiments, the therapy device 102 includes a user interface 126. The user interface 126 may include one or more buttons, dials, sliders, keys, or other input devices configured to receive input from the user. The user interface 126 may also include one or more display devices (e.g., LEDs, LCD displays, etc.), speakers, haptic feedback devices, or other output devices configured to provide information to the user. The user interface 126 may also display warnings generated by the controller 118. For example, the controller 118 may generate a "no canister" warning if the canister 106 is not detected.

[0049] In some embodiments, the therapy device 102 includes a data communication interface 124 (e.g., a USB port, a wireless transceiver, etc.) configured to send and receive data. The communication interface 124 may also include a wired or wireless communication interface (e.g., a jack, an antenna, a transmitter, a receiver, a transceiver, a wire terminal, etc.) for implementing an external data communication system or device. In various embodiments, communication may be direct (e.g., local wired communication or local wireless communication) or via a communication network (e.g., a WAN, the Internet, a cellular network, etc.). For example, the communication interface 124 may include a USB port or an Ethernet card and ports for sending and receiving data via an Ethernet-based communication link or network. In another example, the communication interface 124 may include a Wi-Fi transceiver for communicating via a wireless communication network, cellular phone communication, or mobile phone communication transceiver.

[0050] How to use Referring to Figure 5, a flowchart detailing the steps of Method 500 using the NPWT system 100 according to an exemplary embodiment is shown. As shown in Figure 5, in step 502, the NPWT system 100 (for example, as shown in Figure 1) is provided, and the drape layer 117 and wound dressing 112 of the NPWT system 100 are positioned on the desired wound site 114 to be treated. According to some embodiments, as part of the commencement of treatment in step 502 and before proceeding to the remaining steps of Method 500, any number of different methods may be used to ensure that the drape layer 117 and wound dressing 112 are properly sealed around the wound site 114. For example, according to some embodiments, following the operation of a pneumatic pump 120 to remove air from the wound site 114, pressure may be monitored (e.g., using a pressure sensor 115) to ensure that there is no unintended air leakage from the wound site 114. According to various embodiments, the pressure that can be monitored may be one or more of the following: the pressure in the tube 110, the pressure in the removal fluid canister 106, the pressure in the therapy device 102, the pressure at the wound site 114, the pressure in the pump 120, etc. As understood, in other embodiments, this confirmation of proper sealing between the wound dressing 112 / drape layer 117 and the wound site 114 may alternatively be performed as part of a subsequent step of method 500 and / or during a subsequent step of method 500.

[0051] In some embodiments, in addition to confirming that there are no leaks in the assembled NPWT system 100, step 502 may also optionally include a step of acquiring model data. The model data represents the change in pressure over time as the infusion solution is infused into wound sites of varying volumes under various clinically relevant conditions and states (e.g., different infusion rates, wound volumes, dressing / foam characteristics, dressing air leak rate, starting pressure, predetermined target pressure, etc.). Such model data may be generated using any number of different function approximations, statistical methods, machine learning systems, etc., or a combination thereof. The model data acquired in step 502 may include any number of different pressure decay curves, functions, lookup tables, etc., and may be acquired as existing information input and stored by the controller, and / or may be acquired and processed by the controller 118 during an optional initial training procedure performed by the controller 118 before treating the wound 114 using the NPWT system 100 (e.g., before the start of method 500, or as part of the initial setup of the NPWT system 100 in step 502). Non-limiting examples of embodiments of training procedures in which such relationships may be generated by the controller 118 are outlined in related concurrently pending U.S. Provisional Patent Application No. 62 / 650,132, filed April 17, 2018, entitled WOUND THERAPY SYSTEM WITH WOUND VOLUME ESTIMATION, the entire disclosure of which is incorporated herein by reference. As understood, in embodiments in which the wound site volume 114 is additionally estimated during negative pressure purging in all or part of the negative pressure circuit 200, model data representing the temporal pressure changes as ambient air is allowed to flow into all or part of the negative pressure circuit 200 under various clinically relevant conditions and circumstances may be additionally obtained in substantially similar manner.

[0052] When the NPWT system 100 has been set up in step 502, in step 504 the pneumatic pump 120 is operated (manually or using the controller 118) to achieve a predetermined negative pressure. After the predetermined target pressure is achieved, in step 506 the infusion pump 122 (which may be the same as or different from the pneumatic pump 120) is operated to infuse the infusion fluid 105 into the wound site 114. In step 506 the infusion fluid 105 is infused into the wound site 114 until a predetermined target pressure is achieved. According to various embodiments, the target pressure and / or predetermined negative pressure may correspond to pressures measured in one or more of the following: the tube 110, the removal fluid canister 106, the therapy device 102, the wound site 114, the pump 120, etc. According to various embodiments, a predetermined target pressure may be approximately -15 mmHg to approximately 15 mmHg, more specifically approximately -5 mmHg to 5 mmHg, and even more specifically approximately 0 mmHg.

[0053] In step 508, during the infusion of the fluid 105 into the wound site 114 in step 506, pressure decay (such pressure decay may be an increase in pressure over time) monitored in one or more of the following: the tube 110, the removal fluid canister 106, the therapy device 102, the wound site 114, etc., may be used to estimate the volume of the wound site 114. According to some embodiments, the estimate of the volume of the wound site 114 may be based on a comparison of the dynamic pressure measured during the fluid infusion in step 506 with model pressure decay data acquired before or during step 502. Since the volume of the wound site 114 estimated in step 508 is estimated based on the pressure decay observed during the infusion of the fluid 105 into the wound site 114 in step 506, as described above, the method 500 shown by the flowchart in Figure 5 does not require additional steps and / or time that may otherwise be required to infuse the fluid 105 into the wound site 114. In step 510, the wound site volume 114 estimated in step 508 may optionally be stored for future use.

[0054] Following the estimation of the wound site 114 volume in step 508, in step 512, the NPWT system 100 may be used to continue providing NPWT treatment according to any number of different protocols. According to various embodiments, as shown in step 512 of method 500 in Figure 5, the NPWT treatment may continue with one or more cycles of negative pressure application and fluid infusion using the NPWT system 100, and step 508, in which the wound site 114 volume is estimated, may be repeated after some or all of the additional step 504, in which negative pressure is applied to the wound site 114 and / or step 506, in which the infusion fluid 105 is infused to the wound site 114, or optionally without performing either step.

[0055] The wound site 114 volume estimated using Method 500 in Figure 5 may be used for any number of different purposes. For example, as described above, according to some embodiments, the wound site 114 volume estimated during the infusion phase of an NPWT treatment may be advantageously used to track the progress of wound site 114 healing. Referring to Figure 6, a flowchart of Method 600 for monitoring wound site 114 healing by using estimated wound site 114 volume measurements taken at multiple points in time during an NPWT treatment using an NPWT system 100 is shown according to an exemplary embodiment. As shown in Figure 6, in step 602, an initial wound site 114 volume estimate may be recorded in step 602 to serve as a baseline, and subsequent wound site 114 volume estimates are compared to the baseline to track the progress of healing. According to various embodiments, the estimation of the initial volume of the wound site 114 in step 602 may be performed by (or as) step 508 of Method 500 as described with reference to Figure 5.

[0056] In step 604, the volume of the wound site 114 is estimated and recorded at one or more additional times during the treatment (e.g., once a day), following the initial estimation of the wound site 114 volume in step 602. The time at which such one or more wound site 114 volumes are estimated, and the determined value of the wound site 114 volume, are stored as data points in the memory of the therapy device 102 and / or presented to the user as output of the therapy device 102 (e.g., via the communication interface 124 or the user interface 126). In some embodiments, the estimated wound volume may be plotted as a function of time.

[0057] The additional wound site 114 volumes estimated over one or more additional time intervals during the course of the procedure in step 604 may be estimated by any number of different processes. For example, according to various embodiments, the estimation of the wound site 114 volume in step 604 may be performed by (or as) step 508 of method 500 in Figure 5 during the subsequent occurrence of fluid infusion as part of the continued NPWT treatment of step 512. Alternatively or additionally, one or more of the additional wound site 114 volumes estimated in step 604 may be obtained by any other method, for example, based on the dynamic pressure response observed in the negative pressure circuit 200 of the NPWT system 100 during a purge event.

[0058] Since additional wound site 114 volume estimates are obtained in step 604, in step 606, the changes in the estimated wound site 114 volume over time may be used to determine the healing progress of the wound site 114. For example, step 606 may include comparing the wound site 114 volume estimate obtained in step 604 with one or more previous estimates of the wound site 114 volume (obtained in either step 604 or step 602) to identify changes in the wound site 114 volume. In some embodiments, step 606 may additionally include determining the rate at which the wound site 114 heals based on the changes in the estimated wound site 114 volume over time. In some embodiments, step 606 may include extrapolating or predicting the time it will take for the wound site 114 to heal completely based on a set of wound site 114 volume estimates stored by the controller 118. For example, step 606 may include predicting the time at which the estimated wound site 114 volume reaches zero (or another threshold) based on the initial wound site 114 volume estimated in step 1002 and a series of additional wound site 114 volumes estimated in step 604.

[0059] According to some embodiments, in addition to or as an alternative to using a wound site 114 volume estimate to monitor the healing progress of the wound site 114 (as described, for example, with reference to method 600 in Figure 6 above), the wound site 114 volume estimate may be used to detect and / or prevent overfilling of the wound site 114 with the infusion 105 during the infusion of the infusion 105 into the wound site 115.

[0060] Referring to the method 700 for preventing and / or detecting overfilling of the wound site 115 with the infusion fluid 105 during an infusion event shown in Figure 7, the method 700 begins with step 702, which involves obtaining an initial wound site 114 volume estimate. In embodiments where the infusion event in Figure 7 corresponds to the infusion of fluid during a continued NPWT treatment in step 512, which is described with reference to the method 500 in Figure 5, the initial wound site 114 volume estimate obtained in step 702 may be equal to the wound site 114 volume estimated in step 508 of the method 500 in Figure 5. In embodiments where the method 700 in Figure 7 follows a previous iteration of the method 700 in Figure 7, the wound site 114 volume estimate obtained in step 702 may correspond to the wound site 114 volume estimated in step 720 of the previous iteration of the method 700. In yet another embodiment, the wound site 114 volume estimate obtained in step 702 may be obtained by any number of other methods (for example, the volume estimated in step 810 of method 800 in Figure 8).

[0061] In step 704, the pneumatic pump 120 is operated to achieve a predetermined negative pressure in one or more of the following: the tube 110, the fluid removal canister 106, the therapy device 102, the wound site 114, the pump 120, etc., and subsequently, in step 706, the infusion fluid 105 is infused into the wound site 114. As shown in Figure 7, when the fluid is infused into the wound site 114, according to some embodiments, the pressure in one or more of the following: the tube 110, the fluid removal canister 106, the therapy device 102, the wound site 114, the pump 120, etc., may be optionally monitored in real time in step 708. In such embodiments, this measured real-time pressure can be compared to a model pressure decay curve (such as the model pressure decay curve described with reference to step 502 in method 500 in Figure 5 above) that represents the volume corresponding to the estimated wound site 114 volume obtained in step 702, and the situation as the infusion fluid 105 is infused into the wound site in step 706. As shown in Figure 7, in the event that the measured real-time pressure decay does not correspond to the expected pressure decay of the model pressure decay curve, in step 710, the controller 118 may generate a warning to the user. In the event that the real-time pressure decay is changing at a rate faster than the expected rate, in step 712, the controller 118 may also optionally stop the infusion of the infusion fluid 105 to the wound site 114 to prevent overfilling with the fluid.

[0062] As can be understood, the measured real-time pressure decay may deviate from the expected pressure decay predicted by the model data for any number of reasons. For example, in an embodiment where the volume of the wound site 114 has decreased since the volume of the wound site 114 was last estimated, it is assumed that the pressure decay observed as a result of the current smaller dimensions of the wound site 114 will deviate from the expected pressure decay predicted by the model data. Therefore, in some embodiments, the controller 118 may be configured to generate an alarm in step 710 and / or stop the infusion of the drip solution 105 in step 712 only in the event that the difference between the measured pressure decay and the expected pressure decay exceeds a predetermined threshold. According to some embodiments, this threshold may correspond to a difference of more than about ±15 percent, more specifically more than about ±10 percent, and even more specifically more than about ±5 percent.

[0063] If no difference is detected in step 708 between the real-time pressure measurement and the expected pressure measurement (or if the difference does not exceed a predetermined threshold), step 714 determines whether a predetermined target pressure has been achieved in one or more of the following: the tube 110, the removal fluid canister 106, the therapy device 102, the wound site 114, the pump 120, etc. If it is determined that the measured pressure is substantially equal to the predetermined target pressure, step 716 stops the infusion of the drip solution 1045. According to various embodiments, the predetermined target pressure in step 714 may be approximately -15 mmHg to approximately 15 mmHg, more specifically approximately -5 mmHg to 5 mmHg, or even more specifically approximately 0 mmHg.

[0064] According to some embodiments, if the target pressure has not yet been achieved in step 714, step 706 (and optionally step 708 (comparing the monitored pressure with an expected pressure based on model data) of infusing fluid into the wound site 114) may be repeated until it is determined in step 714 that the target pressure has been achieved.

[0065] However, as shown in Figure 7, according to some embodiments, Method 700 may optionally include step 718, which can provide an additional layer of safety protection against overfilling of the NPWT system 100 in situations where the comparison of the measured wound site 114 pressure with the target pressure is insufficient to detect a potential overfilling condition. In such embodiments, in step 718, the total volume of infusion fluid 105 infused into the wound site 114 from the beginning of step 706 may be compared with the estimated wound site 114 volume obtained in step 702, and the infusion of infusion fluid 105 is stopped in step 716 if it is determined that the volume of the infused fluid is substantially the same as the estimated wound site 114 volume. As understood, by preventing the infusion of an amount of infusion fluid 105 exceeding the estimated volume of the wound site 114, step 718 of Method 700 in Figure 7 provides an additional level of protection against overfilling of the NPWT system 100. Alternatively, if the volume of the infused fluid 105 is less than the estimated volume of the wound site 114, method 700 may continue the infusion of the fluid into the wound site 114 in step 706.

[0066] According to some embodiments, in step 720, the current volume of the wound site 114 may be optionally estimated based on the most recent fluid infusion in step 706, and in step 722, this most recent estimated wound site 114 volume is stored for any number of future uses (e.g., for future fluid infusions according to method 700 in Figure 7, to monitor the healing of the wound site 114 according to method 600 in Figure 6, etc.). In a situation where the fluid infusion is stopped in step 716 in response to the determination in step 714 that the target pressure has been achieved, the wound site 114 volume may be estimated in a manner similar to that described with reference to step 508 of method 500 in Figure 5, where the pressure decay observed in one or more of the tube 110, the removal fluid canister 106, the therapy device 102, the wound site 114, the pump 120, etc., during the fluid infusion is compared with model pressure decay data to identify the corresponding volume of the wound site 114. If the infusion of the infusion solution 105 is stopped in step 716 in response to the determination in step 718 that the volume of the infusion solution is substantially equal to or greater than the estimated volume of the wound site 114, then, according to some embodiments, the estimated volume of the wound site 114 in step 720 may correspond to the previous estimated volume of the wound site 114.

[0067] As described above, according to some embodiments, it may be desirable to compare the estimated wound site 114 volume (for example, as described with reference to Method 500 in Figure 5 and / or Method 700 in Figure 7) obtained during fluid infusion into the wound site 114 with wound site 114 volume estimates obtained by any number of other different methods. Referring to Figure 8, an exemplary embodiment of such Method 800 is shown in which the wound site 114 volume estimate obtained during fluid infusion is compared with the wound site 114 volume estimated by another method (or vice versa). More specifically, in Method 800 shown by the flowchart in Figure 8, for example, as described in the embodiment with reference to Figure 4, the wound site 114 volume estimate based on the dynamic pressure response observed during purging of various parts of the negative pressure circuit 200 of the NPWT system 100 is compared with the wound site 114 volume estimate based on fluid infusion to provide the NPWT system 100 with a more reliable wound site 114 volume estimate.

[0068] As shown in Figure 8, according to one embodiment of method 800, in step 802, the pneumatic pump 120 is operated to achieve a desired negative pressure in the negative pressure circuit 200. As understood, in embodiments where the tube valve 111' is in a closed configuration, step 802 may additionally include a step of opening the tube valve 111'. When a desired negative pressure is achieved in the negative pressure circuit 200, the negative pressure circuit 200 is purged by allowing air from the ambient environment to flow into the negative pressure circuit 200 (e.g., via a calibrated leak system 113) until a predetermined threshold pressure is achieved in the negative pressure circuit 200. When the negative pressure circuit 200 is purged in step 804, the pressure decay in the negative pressure circuit 200 is monitored (e.g., using pressure sensors 115).

[0069] When a predetermined threshold pressure is achieved in the negative pressure circuit 200, the pneumatic pump 120 is activated again in step 806 to remove air from the negative pressure circuit 200 and achieve a desired negative pressure in the negative pressure circuit 200. When this desired negative pressure is achieved, the tube valve 111' is closed in step 808, thereby fluid-isolating the removal fluid canister circuit from the wound site circuit.

[0070] In step 810, the removal fluid canister circuit is purged by allowing air from the ambient environment to flow into the removal fluid canister circuit (e.g., via a calibrated leak system 113) until a predetermined threshold pressure is achieved within the removal fluid canister circuit. While the removal fluid canister circuit is purged during step 810, the pressure decay within the removal fluid canister circuit is monitored (e.g., using a pressure sensor 115). In step 812, a first volume of the wound site 114 is estimated using the pressure decay observed in the negative pressure circuit 200 and the removal fluid canister circuit during steps 804 and 810, respectively. More specifically, the volume of the wound site 114 may be calculated by comparing the pressure decay observed in steps 804-810 with model pressure decay data to identify the corresponding volumes representing the volumes of the negative pressure circuit 200 and the removal fluid canister circuit, from which the wound site 114 may be estimated. As illustrated with reference to steps 802–812 of Method 800 in Figure 8, non-limiting examples of additional methods and / or system embodiments in which the wound site volume 114 can be calculated using the pressure attenuation observed during the purging of part or all of the negative pressure circuit 200 are outlined in related concurrently pending U.S. Provisional Patent Application No. 62 / 714,229, filed on 3 August 2018 and titled WOUND THERAPY SYSTEM WITH WOUND VOLUME ESTIMATION, the entire disclosure of which is incorporated herein by reference.

[0071] In step 814, the infusion 105 is infused into the wound site 114 until a predetermined pressure is achieved in one or more of the tube 110, the removal fluid canister 106, the therapy device 102, the wound site 114, the pump 120, etc., as described with reference to step 506 of method 500 in Figure 5. In step 816, the volume of the second wound site 114 is estimated in a manner similar to that described with reference to step 508 of method 500 in Figure 5, based on the pressure decay observed in one or more of the tube 110, the removal fluid canister 106, the therapy device 102, the wound site 114, the pump 120, etc., during the infusion of the fluid into the wound site 114 in step 814. As can be understood, according to some embodiments, steps 814 and 816 may optionally be performed before steps 810 and 812, or alternatively, simultaneously with steps 810 and 812.

[0072] In step 818, the first wound site 114 volume estimated in step 812 is compared with the second wound site 114 volume estimated in step 816. If it is determined in step 818 that the first and second volumes are not substantially similar to each other, a warning may be generated in step 820. If it is determined in step 818 that the first and second volumes are substantially similar to each other, in step 822, one, both, or the mean of the first wound site 114 volume estimate and the second wound site 114 volume estimate are stored. As can be understood, any similarity metric may be used in step 818 to determine whether the first and second volumes are substantially similar to each other. According to some embodiments, it may be determined in step 818 that the first and second volumes are substantially similar to each other if they differ from each other by about 15 percent or less, more specifically about 10 percent or less, and even more specifically about 5 percent or less.

[0073] As can be understood, Method 800 in Figure 8 may be performed any number of times and at any point in time during an NPWT treatment provided using the NPWT system 100. For example, according to some embodiments, Method 800 may be performed during the initial use of the NPWT system 100, and thereafter the NPWT system 100 may be operated by any number of other different NPWT treatments or other treatments, protocols, or by any number of other methods disclosed herein. In embodiments in which Method 700 in Figure 7 follows Method 800 in Figure 8, the wound site 114 volume estimate obtained in step 702 during the initial iteration of Method 700 may correspond to the wound site 114 volume estimate stored in step 820 of Method 800. In subsequent iterations of Method 700, the wound site 114 volume estimate obtained in step 702 may correspond to the wound site 114 volume stored in step 722 during the immediately preceding iteration of Method 700.

[0074] In other embodiments, part or all of Method 800 in Figure 8 may be repeated any desired number of times. For example, in some embodiments, it may be desirable to cross-check the wound site 114 volume estimated based on the purge events in steps 804 and 810 with the wound site 114 volume estimated based on the fluid infusion in step 814 at each iteration of Method 800, in which case Method 800 in Figure 8 may be repeated in its entirety at each iteration. In other embodiments, it may be desirable to alternate between estimating the wound site 114 volume based on the purge events in steps 804 and 810 and estimating the wound site 114 volume based on the fluid infusion in step 814. Additionally, according to various embodiments (including the embodiment in Figure 8 above), some or all iterations of method 800 in Figure 8 may optionally incorporate some or all of steps 708, 710, 712, 714, 716, 718, and 720 of method 700 in Figure 700 between steps 815 and 816. According to various embodiments, method 600 for monitoring wound site 114 healing in Figure 6 may also be incorporated into any of the methods disclosed herein.

[0075] Generally, the volume of the wound site 114 is defined by the entire interior extending between the wound site 114 and the drape layer 117 attached to the surrounding skin 116. Various points during treatment using the NPWT system 100 that are located within the volume of the wound site and define the volume of the wound site may be any one of the wound dressing 112, the fluid 121, and / or dead space 119, or any combination thereof. As understood, unless the wound dressing 112 is changed during treatment, the volume of the wound site 114 occupied by the wound dressing 112 generally remains unchanged throughout the course of treatment, but a portion of the wound site 114 volume occupied by the fluid 121 and / or dead space 119 may change over time.

[0076] As can be understood, according to various embodiments, the controller 118 may be programmed to enable the NPWT system 100 to determine the volume relative to the wound site 114 using any or all of the methods described herein.

[0077] Configuration of an exemplary embodiment The construction and configuration of the systems and methods shown in the various exemplary embodiments are for illustrative purposes only. While only a few embodiments are described in detail in this disclosure, many modifications are possible (e.g., variations in the size, dimensions, structure, shape and proportion of various elements, parameter values, mounting configuration, material use, color, orientation, etc.). For example, the position of elements can be reversed or varied, and the properties, number, or position of separate elements can be changed or varied. Therefore, all such modifications are intended to be included within the scope of this disclosure. Any order or sequence of process or method steps can be varied or rearranged by alternative embodiments. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions, and configuration of the exemplary embodiments without departing from the scope of this disclosure.

[0078] This disclosure envisions methods, systems, and program products on any machine-readable medium for achieving a variety of operations. Embodiments of this disclosure can be implemented using existing computer processors, or by dedicated computer processors for appropriate systems incorporated for this purpose or otherwise, or by hardwired systems. Embodiments within the scope of this disclosure include program products that include a machine-readable medium for carrying or having machine-executable instructions or data structures stored thereon. Such a machine-readable medium may be any available medium accessible by a general-purpose or dedicated computer, or by other machines equipped with a processor. For example, such a machine-readable medium may include RAM, ROM, EPROM, EEPROM, CD-ROM, 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 is accessible by a general-purpose or dedicated computer or other machine equipped with a processor. Combinations of the above also fall within the scope of machine-readable medium. Machine-executable instructions include, for example, instructions and data that cause a general-purpose computer, a dedicated computer, or a dedicated processing machine to perform a particular function or set of functions.

[0079] While the diagram illustrates a specific order of method steps, the order of steps may differ from that shown. Furthermore, two or more steps can be performed simultaneously or partially simultaneously. Such variations depend on the selected software and hardware systems and on the designer's choice. All such variations are within the scope of this disclosure. Similarly, software implementations can be achieved using standard programming techniques employing rule-based logic and other logic to accomplish various connection, processing, comparison, and decision steps.

Claims

1. It is a wound healing system, A pump configured to generate negative pressure at the wound site and drip fluid into the wound site, A wound dressing configured to be applied to the wound site, The pump is connected to the wound dressing via a fluid tube, It is a controller, During the infusion of the fluid into the wound site, monitor the pressure of at least one of the wound dressing, the wound site, or the fluid tube, and The pressure measurements obtained from at least one of the pressures of the wound dressing, the wound site, or the fluid tube, monitored during the infusion of the fluid into the wound site, are compared with model pressure decay data to identify a known volume corresponding to the closest pressure decay data, and the volume of the fluid infused into the wound site is further determined. A controller configured in such a way Equipped with, The model pressure decay data includes pressure decay data for each of the plurality of containers, each having a known volume, when a predetermined amount of fluid is dripped into each of the plurality of containers, and the pressure decay data is data showing the increase in pressure over time. Wound healing system.

2. The wound therapy system according to claim 1, wherein the controller is configured to store the determined volume of the fluid infused into the wound site.

3. The wound therapy system according to claim 1, wherein the controller is configured to determine the volume of fluid infused into the wound site in each of one or more infusion events that occur during treatment of the wound site.

4. The wound therapy system according to claim 3, wherein the controller is configured to store each of the determined volumes.

5. The wound therapy system according to claim 4, wherein the controller is configured to monitor the healing of the wound site based on the stored and determined volume.

6. The wound therapy system according to claim 1, further comprising a source for supplying an intravenous fluid, wherein the pump comprises a pneumatic pump for generating negative pressure at the wound site and an intravenous pump for supplying the intravenous fluid to the wound site, and the controller is further configured to operate the intravenous pump to infuse the intravenous fluid into the wound site.

7. The wound therapy system according to claim 6, wherein the controller is configured to stop the intravenous drip to the wound site when a first predetermined pressure is detected.

8. The wound therapy system according to claim 6, wherein the controller is configured to stop the operation of the infusion pump when a pressure of substantially 0 mmHg is detected.

9. The wound therapy system according to claim 6, wherein the controller is further configured to operate the pneumatic pump to remove air from the wound site.

10. The wound therapy system according to claim 1, further comprising a source of intravenous fluid.

11. The pump includes an air pump for generating negative pressure at the wound site and an intravenous pump for supplying intravenous fluid to the wound site, The aforementioned controller The air pump is operated to remove air from the wound site and achieve a predetermined negative pressure. When it is detected that the pressure is equal to the predetermined negative pressure, the infusion pump is operated to infuse the infusion solution into the wound site, and When it is detected that the measured pressure is equal to a predetermined target pressure, the infusion of the drip solution to the wound site is stopped. The wound therapy system according to claim 10, further configured as follows.

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