Wound therapy system with wound volume estimation

Abstract

The present application relates to a wound therapy system with wound volume estimation. A pump generates a vacuum at a wound site via a first tube. A negative pressure circuit is defined by the tank, the first tube, and the wound site. A controller of the therapy apparatus operates the pump to apply a first negative pressure to the entire negative pressure circuit, after which ambient air is allowed to flow into the negative pressure circuit. The controller further operates the pump to apply a second negative pressure to a selected portion of the negative pressure circuit other than the wound site, after which ambient air is allowed to flow into the selected portion. By comparing a measured parameter related to the flow of air into the negative pressure circuit to a parameter measured with respect to the flow of air into the selected portion, an amount of fluid delivered to the wound site via a second tube is determined.

Description

[0001] This application is a divisional application of the application filed on March 26, 2019, with application number 201980047515.8 and invention title "Wound Treatment System with Wound Volume Estimation".

[0002] Cross-references to related applications

[0003] This application claims the benefit of priority to U.S. Provisional Application 62 / 714229, filed August 3, 2018, the entire contents of which are incorporated herein by reference. Background Technology

[0004] This disclosure relates generally to a wound treatment system, and more specifically to a wound treatment system configured to estimate the volume relative to the wound site.

[0005] Negative pressure wound therapy (NPWT) is a type of wound treatment involving the application of negative pressure to the treatment site to promote wound healing. Recent advances in utilizing NPWT for wound healing involve applying topical fluids to the wound in combination with NPWT. However, determining the appropriate volume of fluid delivered to the wound can be challenging. Furthermore, accurately monitoring and tracking the wound healing process over time can be difficult. Therefore, it is advantageous to provide a system and method that allows for accurate and reliable estimation of the available space at the wound site into which the fluid can be delivered and for estimating the wound healing process over time. Advantageously, such a system and method will further allow for such volume determination, automated by a controller, to be performed at any stage during NPWT treatment and can account for variations in the type or size of the fluid removal vessel used during NPWT treatment. Summary of the Invention

[0006] In one embodiment of this disclosure, the wound treatment system includes a treatment device, a tube, a valve, and an opening formed through a first tube portion. The treatment device includes: a canister configured to collect wound exudate from a wound; and a pump fluidly connected to the canister and configured to draw negative pressure within the canister. The tube has a first end and a second end. The first end of the tube is attached to and fluidly connected to the canister. The valve is connected to the tube at a location between the first and second ends. The valve is configured to prevent flow if a minimum threshold negative pressure is not met, and to allow flow if the threshold negative pressure is met. The first tube portion is defined between the first end of the tube and the valve. A second tube portion is defined between the second end of the tube and the valve. The opening is configured to allow fluid communication between the first tube portion and ambient atmospheric pressure.

[0007] According to some embodiments, the tube is defined by an outer wall. An opening extends through the outer wall of the tube. According to some embodiments, a second end of the tube is attached to a wound dressing, which is configured to seal to a surface to define a treatment space. When the valve is subjected to a pressure less than or equal to a threshold minimum negative pressure, the fluid reservoir is in fluid communication with the treatment space.

[0008] According to some embodiments, the wound treatment system may also include a controller configured to operate a pump to draw a predetermined first negative pressure from the canister. The first predetermined negative pressure may be greater than a threshold minimum negative pressure. The controller may be configured to calculate a first volume based on a measured time required for the canister pressure to increase from the predetermined first negative pressure to a predetermined baseline pressure.

[0009] According to some implementations, the controller may also be configured to operate the pump to draw in a predetermined second negative pressure within the canister and treatment space that is less than a threshold minimum negative pressure. The controller is also configured to calculate a second volume based on a measured time required for the pressure within the canister and treatment space to increase from the predetermined second negative pressure to a predetermined baseline pressure.

[0010] According to some implementations, the controller can also be configured to calculate the volume of the treatment space based on the difference between a first calculated volume and a second calculated volume. The controller can also be configured to calculate the volume of the treatment space based on subtracting the known volume of the tube from the calculated difference between the first calculated volume and the second calculated volume.

[0011] According to some embodiments, a graduated leak detector is fluidly connected to an opening in the pipe and configured to measure the rate at which air flows through the opening. The controller performs calculations for the first and second volumes respectively based on the air flow rates through the openings detected by the leak detector.

[0012] According to some implementation schemes, the valve is configured to remain in an open configuration, in which the first and second pipe segments are in fluid communication after the valve has experienced a minimum threshold negative pressure. The valve is capable of reverting from the open configuration to an initial closed configuration, in which the valve prevents fluid communication between the first and second pipe segments until the pressure is less than or equal to the threshold negative pressure.

[0013] According to some embodiments, the wound treatment system also includes a first pressure sensor in fluid communication with a first tubing segment. After a predetermined time interval following the first pressure sensor detecting a predetermined first negative pressure within the first tubing segment, the controller can stop operating the pump. The wound treatment system may also include a second pressure sensor in fluid communication with a second tubing segment.

[0014] According to some implementations, the controller is configured to stop the pump operation after a predetermined time interval following the detection of a predetermined second negative pressure within the second pipe segment by the second pressure sensor. An opening in the pipe may define a graduated leak of known size through which air from ambient atmospheric pressure can flow into the pipe.

[0015] In one specific embodiment of this disclosure, a method of operating a wound treatment device includes: operably connecting a first end of a fluid conduit to a fluid reservoir and a pump of the treatment device, and operably connecting a second end of the fluid conduit to a wound dressing. The pump is operated to apply a first predetermined negative pressure to a first volume including the fluid reservoir but excluding the wound dressing. The pump is stopped for a period of time during which the first predetermined negative pressure within the first volume increases to a baseline pressure within a first time period. A first volume of the first volume is determined using the first time period. The pump is operated to apply a second predetermined negative pressure to a second volume including the first volume and the wound dressing. The pump is stopped for a period of time during which the second predetermined negative pressure within the second volume increases to a baseline pressure within a second time period. A second volume of the second volume is determined using the second time period. The infusion volume of the first wound dressing to be delivered is determined at least in part based on the difference between the first volume and the second volume.

[0016] According to some implementation schemes, the first predetermined negative pressure is different from the second predetermined negative pressure. The first predetermined negative pressure may be greater than the second predetermined negative pressure.

[0017] According to some embodiments, a valve is operatively connected to the fluid conduit at a position between a first end and a second end of the fluid conduit. The valve may be configured to prevent flow between the fluid conduit and the wound dressing when subjected to a pressure equal to or greater than a first predetermined negative pressure. According to some embodiments, the valve is configured to allow flow between a first portion of the fluid conduit and the wound dressing when subjected to a second predetermined negative pressure.

[0018] According to some embodiments, the pump is operated to deliver a first infusion volume of fluid to the wound dressing. At a point in time before the pump is operated to apply a first predetermined negative pressure to the first volume, the pump is operated to apply a second predetermined negative pressure to the second volume.

[0019] According to some embodiments, after the step of delivering the infusion fluid into the treatment space, the pump is operated to apply a third predetermined negative pressure to the first volume. The pump is then stopped for a period of time, during which the third predetermined negative pressure in the first volume increases to a second baseline pressure within a third time period. After the pressure in the tubing has reached the second baseline pressure, the pump is operated to apply a fourth predetermined negative pressure to the second volume. The pump is then stopped for a period of time, during which the fourth predetermined negative pressure in the second volume increases to the second baseline pressure within a fourth time period.

[0020] According to some implementation schemes, the third predetermined negative pressure is greater than the fourth predetermined negative pressure. The third predetermined negative pressure is equal to the first predetermined negative pressure. According to some implementation schemes, the fourth predetermined negative pressure is equal to the second predetermined negative pressure.

[0021] According to some embodiments, the pump is operated to deliver a second wound dressing infusion fluid volume to the wound dressing. At a time point prior to operating the pump to apply a third predetermined negative pressure to the first volume, the pump is operated to apply a fourth predetermined negative pressure to the second volume. The second wound dressing infusion fluid volume delivered to the wound dressing is based on a comparison of a third time period and a fourth time period. The relative difference between the first and second time periods may be greater than the relative difference between the third and fourth time periods. According to some embodiments, the first wound dressing infusion fluid volume is greater than the second wound dressing infusion fluid volume.

[0022] According to some implementations, the fluid tank is empty when the pump is operated to apply a first predetermined negative pressure and when the pump is operated to apply a second predetermined negative pressure, and the fluid tank is at least partially full when the pump is operated to apply a third predetermined negative pressure and when the pump is operated to apply a fourth predetermined negative pressure.

[0023] According to some implementation schemes, the relative difference between the first and second time periods is less than the relative difference between the third and fourth time periods. The infusion volume of the first wound dressing is less than the infusion volume of the second wound dressing.

[0024] In one specific embodiment of this disclosure, a method of delivering an infusion fluid to a wound dressing includes: measuring a first volume representing at least a fluid reservoir associated with a wound treatment device; and measuring a second volume representing at least the fluid reservoir and the wound dressing. The first volume is subtracted from the second volume to obtain a third volume. An infusion volume is calculated based on the third volume. An infusion fluid volume equal to the infusion volume is delivered to the wound dressing via the wound treatment device.

[0025] According to some implementation schemes, calculating the infusion volume involves multiplying a third volume by an infusion adjustment factor, and the first volume does not include the volume of the wound dressing.

[0026] According to some embodiments, the first volume is measured by operating a pump fluidly attached to a fluid tank to completely fill the first volume with a first fluid volume; and measuring the volume of the first fluid volume. The fluid includes ambient air discharged into the first volume. According to some embodiments, the ambient air is discharged into the first volume via an opening formed in a fluid conduit that extends between and fluidly connects the fluid tank and the wound dressing.

[0027] According to some implementation schemes, the pump is operated to create a first negative pressure within the first volume, and in response to stopping the pump, ambient air is discharged into the first volume. The first ambient air volume is measured based on a first time period during which the first negative pressure within the first volume increases to ambient pressure.

[0028] According to some embodiments, the second volume is measured by operating a pump to completely fill the second volume with a second fluid volume; and measuring the volume of the second fluid volume. The fluid includes ambient air discharged into the second volume. The ambient air can be discharged into the second volume through an opening formed in a fluid conduit.

[0029] According to some implementation schemes, the pump is operated to create a second negative pressure within the second volume, and in response to stopping the pump, ambient air is discharged into the second volume. The second ambient air volume is measured based on a second time period, during which the second negative pressure within the second volume increases to ambient pressure.

[0030] According to some embodiments, the valve is operatively connected to a fluid line between the opening and the wound dressing. The valve is configured to: prevent flow between the fluid reservoir and the wound dressing at a pressure equal to or greater than a first predetermined negative pressure; and permit flow at a second predetermined negative pressure.

[0031] According to some embodiments, at a point in time after the pump is operated to form a first negative pressure within the first volume, the pump is operated to form a second negative pressure within the second volume. At a point in time before the pump is operated to form a first negative pressure within the first volume, the pump is operated to form a second negative pressure within the second volume.

[0032] In one specific embodiment of this disclosure, a method for monitoring wound healing progress includes operating a pump of a treatment device to measure a first volume of a wound on which a wound dressing in fluid communication with the treatment device is applied. Based on the first volume of the wound, a first infusion volume of fluid is delivered to the wound via the treatment device. After a first predetermined time period following the delivery of the infusion fluid, the pump is operated to measure a second volume of the wound. A first healing rate is calculated based on the difference between the first and second wound volumes and the duration of the first predetermined time period.

[0033] According to some embodiments, a second infusion fluid volume is delivered to the wound based on a second wound volume. After a second predetermined time period following the delivery of the infusion fluid, the pump is operated to measure a third wound volume. A second healing rate is calculated based on the difference between the second and third wound volumes and the duration of the second predetermined time period. The second healing rate is compared to a first healing rate. According to some embodiments, the user is alerted if the second healing rate is less than the first healing rate.

[0034] Those skilled in the art will understand that the invention is merely illustrative and not intended to be limiting in any way. Other aspects, inventive features, and advantages of the apparatus and / or process described herein will become apparent from the specific embodiments set forth herein and in conjunction with the accompanying drawings, as defined only by the claims. Attached Figure Description

[0035] Figure 1 This is a block diagram of a negative pressure wound therapy system according to an exemplary embodiment, the negative pressure wound therapy system including a treatment device connected to a wound dressing via a tube.

[0036] Figure 2 This illustrates in more detail the exemplary implementation. Figure 1 A block diagram of a negative pressure wound therapy system.

[0037] Figure 3 This illustrates in more detail the exemplary implementation. Figure 1 A block diagram of the negative pressure circuit, the fluid removal tank circuit, and the wound site circuit of the negative pressure wound therapy system.

[0038] Figure 4 This is a block diagram illustrating a negative pressure wound therapy system according to an exemplary embodiment.

[0039] Figure 5 This is a flowchart of a method for using a negative pressure wound therapy system according to an exemplary embodiment.

[0040] Figure 6A This is a flowchart of a method for infusing an initial fluid volume into a wound site using a negative pressure wound therapy system according to an exemplary embodiment.

[0041] Figure 6B An example of a negative pressure wound therapy system, according to an exemplary embodiment, is described, which applies an initial fluid volume to a desired wound site before it is infused into the wound site.

[0042] Figure 6C An example is illustrated according to an exemplary embodiment, after applying a first negative pressure to a negative pressure wound therapy system. Figure 6B The negative pressure wound therapy system.

[0043] Figure 6D Examples of implementation schemes are illustrated in such a way. Figure 6C As shown, during the degassing process of the negative pressure wound therapy system after the first negative pressure is applied. Figure 6C The negative pressure wound therapy system.

[0044] Figure 6E An example is illustrated according to an exemplary embodiment, after applying a second negative pressure to a negative pressure wound therapy system. Figure 6BThe negative pressure wound therapy system.

[0045] Figure 6F Examples of implementation schemes are illustrated in such a way. Figure 6E As shown, during the degassing process of the negative pressure wound therapy system after the application of the second negative pressure. Figure 6E The negative pressure wound therapy system.

[0046] Figure 6G The use according to the exemplary implementation is illustrated. Figure 6B The wound treatment system drips fluid onto the wound site.

[0047] Figure 7 An example of a negative pressure wound therapy system, according to an exemplary embodiment, is shown, which applies pressure to the wound site after an initial infusion of fluid.

[0048] Figure 8A This is based on the use of the exemplary implementation scheme. Figure 7 A flowchart illustrating a method for a negative pressure wound therapy system to infuse additional fluid into the wound site.

[0049] Figure 8B An example is illustrated according to an exemplary embodiment, after applying a first negative pressure to a negative pressure wound therapy system. Figure 7 The negative pressure wound therapy system.

[0050] Figure 8C Examples of implementation schemes are illustrated in such a way. Figure 8B As shown, during the degassing process of the negative pressure wound therapy system after the first negative pressure is applied. Figure 8B The negative pressure wound therapy system.

[0051] Figure 8D An example is illustrated according to an exemplary embodiment, after applying a second negative pressure to a negative pressure wound therapy system. Figure 7 The negative pressure wound therapy system.

[0052] Figure 8E Examples of implementation schemes are illustrated in such a way. Figure 8D As shown, during the degassing process of the negative pressure wound therapy system after the first negative pressure is applied. Figure 8D The negative pressure wound therapy system.

[0053] Figure 9A This is based on the use of the exemplary implementation scheme. Figure 7 A flowchart illustrating a method for a negative pressure wound therapy system to infuse additional fluid into the wound site.

[0054] Figure 9B An example is illustrated according to an exemplary embodiment, after applying a first negative pressure to a negative pressure wound therapy system. Figure 7 The negative pressure wound therapy system.

[0055] Figure 9C Examples of implementation schemes are illustrated in such a way. Figure 9B As shown, during the degassing process of the negative pressure wound therapy system after the first negative pressure is applied. Figure 9B The negative pressure wound therapy system.

[0056] Figure 9D An example is illustrated according to an exemplary embodiment, after applying a second negative pressure to a negative pressure wound therapy system. Figure 7 The negative pressure wound therapy system.

[0057] Figure 9E Examples of implementation schemes are illustrated in such a way. Figure 9D As shown, during the degassing process of the negative pressure wound therapy system after the first negative pressure is applied. Figure 9D The negative pressure wound therapy system.

[0058] Figure 10A This is a flowchart of a method for determining whether a sufficient dead space exists in a negative pressure wound therapy system, according to an exemplary embodiment.

[0059] Figure 10B An example is illustrated according to an exemplary embodiment, after applying a first negative pressure to a negative pressure wound therapy system. Figure 7 The negative pressure wound therapy system.

[0060] Figure 10C Examples of implementation schemes are illustrated in such a way. Figure 10B As shown, during the degassing process of the negative pressure wound therapy system after the first negative pressure is applied. Figure 10B The negative pressure wound therapy system.

[0061] Figure 11 This is a flowchart of a process for monitoring the healing process of a wound site over time, according to an exemplary embodiment. Detailed Implementation

[0062] Overview

[0063] Referring generally to the accompanying drawings, a wound treatment system according to various exemplary embodiments is illustrated. The wound treatment system may include a treatment device and a wound dressing. The treatment device may include an infusion fluid canister, a removal fluid canister, a valve, a pneumatic pump, an infusion pump, and a controller. The wound dressing may be applied to the skin around a patient's wound. The treatment device may be configured to deliver infusion fluid to the wound and provide negative pressure wound therapy (NPWT) by maintaining the wound under negative pressure. The components of the wound treatment device, the wound dressing, and the wound site form a negative pressure loop.

[0064] The controller may be configured to operate a pneumatic pump, an infusion pump, and / or other controllable components of the treatment device. In some embodiments, the controller estimates the wound volume based on a comparison of the observed dynamic pressure response to negative pressure applied to the entire negative pressure circuit versus negative pressure applied to a selected portion of the negative pressure circuit. Based on the comparison of the observed dynamic response, the controller may be configured to determine the amount of fluid to be infused to the wound site.

[0065] According to some embodiments, the volume relative to the wound site determined by the controller can be related to the dead space at the wound site (i.e., the available space surrounding the wound site within the applied sterile drape layer to which the infusion fluid can be delivered). In some such embodiments, the controller can be configured to determine the amount of infusion fluid to be delivered to the wound site based on a predetermined percentage (e.g., 20%, 50%, 80%, etc.) of the calculated dead space volume at the wound site. The controller can then operate the infusion pump to deliver the determined volume of infusion fluid to the wound. By basing the amount of infusion fluid to be delivered to the wound site on the calculated dead space volume at the wound site, the negative pressure system can be configured to provide more efficient and precise delivery of the infusion fluid, which reduces the risk of leakage due to over-delivery of the infusion fluid and the risk of ineffective wound site treatment due to under-delivery of the infusion fluid.

[0066] In some implementations, during wound treatment, the controller may, in addition to or alternatively, measure and monitor the volume relative to the wound site multiple times, wherein the controller determines the wound healing progress based on changes in the measured volume relative to the wound site during NPWT treatment. By monitoring the wound healing progress, the controller can be configured to alert the user if wound healing is not proceeding as expected or desired. These and other features of the wound treatment system are described in detail below.

[0067] Wound Treatment System

[0068] See now Figure 1This document illustrates a negative pressure wound therapy (NPWT) system 100 according to an exemplary embodiment. The NPWT system 100 is shown as including a treatment device 102 fluidly connected via tubes 108 and 110 to a wound dressing 112. According to various embodiments, the wound dressing 112 may be placed on or within a wound site 114 and adhered to or sealed to the skin 116 surrounding the wound site 114 using a sterile cover layer 117. Several examples of wound dressings 112 that may be used in combination with the NPWT system 100 are also described in detail in U.S. Patent 7,651,484, issued January 26, 2010; U.S. Patent 8,394,081, issued March 12, 2013; and U.S. Patent Application 14 / 087418, filed November 22, 2013. The entire disclosure of each of these patents and patent applications is incorporated herein by reference.

[0069] like Figure 2 As illustrated in the block diagram, the treatment device 102 generally includes a pneumatic pump 120, an infusion pump 122, a filter 128, and a controller 118. The pneumatic pump 120 is fluidly coupled to a removal fluid tank 106 (e.g., via conduit 136) and can be configured to evacuate the tank 106 by pumping air out of the tank. In some embodiments, the pneumatic pump 120 is configured to operate in both a forward and reverse direction. For example, the pneumatic pump 120 can operate in the forward direction to pump air out of the tank 106 and reduce the pressure within the tank 106. The pneumatic pump 120 can operate in the reverse direction to pump air into the tank 106 and increase the pressure within the tank 106. The pneumatic pump 120 can be controlled by the controller 118, which will be described in more detail below.

[0070] Treatment device 102 may be configured to provide negative pressure wound therapy by reducing pressure at wound site 114. Treatment device 102 may create a vacuum (relative to atmospheric pressure) at wound site 114 by removing wound exudate, air, and other fluids from wound site 114. Wound exudate may include fluids filtered from the patient's circulatory system to the lesion or inflamed area. For example, wound exudate may include water and dissolved solutes such as blood, plasma proteins, white blood cells, platelets, and red blood cells. Other fluids 121 removed from wound site 114 may include infusion fluid 105 previously delivered to wound site 114. Infusion fluid 105 may include, for example, cleansing fluids, prescription fluids, drug-loaded fluids, antibiotic fluids, or any other type of fluid that may be delivered to wound site 114 during wound treatment. Infusion fluid 105 may be maintained in infusion fluid canister 104 and controllably dispensed to wound site 114 via tubing 108. In some embodiments, infusion fluid canister 104 may be detachable from treatment device 102 to allow refilling and replacement of canister 106 as needed.

[0071] The infusion pump 122 is fluidly connected to the infusion fluid reservoir 104 via an upstream infusion line 108a and to the wound dressing 112 via a downstream infusion line 108b. The infusion pump 122 is operable to deliver infusion fluid 105 to the wound dressing 112 and the wound site 114 by pumping infusion fluid 105 through the upstream infusion line 108a and the downstream infusion line 108b. The infusion pump 122 may be controlled by a controller 118, which will be described in more detail below. According to some embodiments, the infusion valve 109 is configured to allow flow only in the direction from the infusion fluid reservoir 104 to the wound site 114 (e.g., via a check valve, or via a valve configured to be selectively switched to a closed position by the user and / or controller 118 before applying negative pressure to the wound site), and this infusion valve may typically be located at a position along a portion of the downstream infusion line 108b.

[0072] A filter 128 may be positioned between the fluid removal tank 106 and the pneumatic pump 120 (e.g., along conduit 136) such that air pumped from the tank 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, for example, hydrophobic and / or lipophilic bacterial filters, such that aqueous and / or oily liquids will bead up on the surface of the filter 128. The pneumatic pump 120 may be configured to provide sufficient airflow through the filter 128 such that the pressure drop across the filter 128 is not significant (e.g., such that the pressure drop will substantially not impede the application of negative pressure from the treatment device 102 to the wound site 114).

[0073] The removal fluid canister 106 may be a component of the treatment device 102, configured to collect wound exudate and other fluids 121 removed from the wound site 114. In some embodiments, the removal fluid canister 106 is detachable from the treatment device 102 to allow for emptying and replacement of the canister 106 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, while the upper portion of the canister 106 may be filled with air. The treatment device 102 may be configured to evacuate the canister 106 by pumping air out of the canister 106. The reduced pressure within the canister 106 may be transferred via tubing 110 to the wound dressing 112 and the wound site 114.

[0074] like Figure 1As shown, a tubular valve 111 is positioned along the tubing 110 between the removal fluid reservoir 106 and the wound site 114. This valve is configured to selectively allow and prevent fluid flow between the removal fluid reservoir 106 and the wound site 114. The tubular valve 111 may be defined by any number of different configurations (e.g., spring-biased configurations, duckbill configurations, clamping configurations, check valve configurations, etc.) configured to allow selective control of fluid flow through the tubing 110, and may include configurations to be selectively opened and / or closed by a user in response to a sensed stimulus (e.g., a predetermined threshold pressure) or by a controller 118.

[0075] See Figure 3 The block diagram shows that, when valve 111 is in the open flow configuration, the removal fluid tank 106, tubing 110 (i.e., both upstream tubing portion 110a and downstream tubing portion 110b), conduit 136 extending between the pneumatic pump 120 and the removal fluid tank 106, the portion of the downstream drip tube 108b extending between the sterile drape layer 117 and the drip valve 109, and wound site 114 are fluidly connected to define a negative pressure circuit 200. See also... Figure 3 When valve 111 is in a closed, non-flowing configuration, the removal fluid canister 106, conduit 136, and the upstream tubing portion 110a of tube 110 extending between the removal fluid canister 106 and valve 111 define a removal fluid canister circuit 202. This removal fluid canister circuit is fluidly isolated from the wound site circuit 204, which is defined by the wound site 114, the downstream tubing portion 110b of tube 110 extending between valve 111, the portion of downstream drip tube 108b extending between sterile drape layer 117 and drip valve 109, and the wound site 114. As will be discussed in more detail below, the volume of tube 110, the volume of conduit 136, and the volume of the portion of downstream drip tube 108b extending between sterile drape layer 117 and drip valve 109 define a known volume that can be easily subtracted from or otherwise incorporated into volume calculations relative to the wound site 114.

[0076] See you again Figure 1According to some embodiments, a graduated leakage system 113 is additionally provided along the pipe 110 and operably fluidly connected to the pipe at a location upstream of the pipe valve 111 and downstream of the removal fluid tank 106. This graduated leakage system is defined by a vent 113a formed through the outer wall of the pipe 110, which can be selectively closed by a vent valve 113b. A flow detector 113c may also form part of the graduated leakage system 113, configured to measure the airflow through the vent 113a. As will be described in more detail below, the graduated leakage system 113 is configured to selectively control and measure the airflow between the pipe 110 and the surrounding environment of the treatment device 102. According to various embodiments, the graduated leakage system 113 can be selectively opened to allow airflow into the pipe 110 at a known predetermined rate.

[0077] As will be described in more detail below, when both exhaust valve 113b and pipe valve 111 are closed, the operation of pneumatic pump 120 can be configured to evacuate only the portion of the negative pressure circuit 200 that removes fluid from the tank circuit 202 (such as, for example...). Figure 6E (As illustrated). When exhaust valve 113b is closed and pipe valve 111 is open, the operation of pneumatic pump 120 can be configured to evacuate the entire negative pressure circuit 200 (such as, for example...). Figure 6C (As illustrated). When vent valve 113b is open and pipe valve 111 is closed, airflow from the environment surrounding treatment device 102 can enter through vent port 113a of graded leakage system 113 and fill the vacuum in removal fluid tank circuit 202 (such as, for example) Figure 6F (As illustrated). For example, Figure 6D As shown, when both the exhaust valve 113b and the pipe valve 111 are open, the airflow from the surrounding environment of the treatment device 102 can enter through the exhaust port 113a of the graded leakage system 113 and fill the vacuum in the entire negative pressure circuit 200.

[0078] Although the disclosed graduated leakage system 113 and the portion of the tube 110 extending between the wound site 114 and the removal fluid tank 106 are tandemly positioned, according to some embodiments, such as... Figure 4 As illustrated, the graduated leakage system 113 can also be formed in series with the conduit 136. Figure 4 The operation of the graded leakage system 113 in the implementation scheme is similar to Figure 1 The operation of the illustrated graded leakage system 113, wherein Figure 4 The graded leakage system 113 is configured to provide a path through which air from the surrounding environment can flow in and fill part or all of the negative pressure circuit 200 after a vacuum has been created in part or all of the negative pressure circuit 200. It should be understood that, according to various embodiments, the methods illustrated or disclosed herein incorporate, as... Figure 1Any method or system of the illustrated graded leakage system 113 implementation scheme can be used as follows Figure 4 The implementation scheme of the graduated leakage system 113 shown is modified.

[0079] like Figure 2 As illustrated in the block diagram, according to various embodiments, controller 118 may be configured to operate various components of treatment device 102. Specifically, as will be described in more detail below, according to various embodiments, controller 118 may be configured to control various components of NPWT system 100 to perform one or more volume determination processes, via which, for example, the volume 105 of infusion fluid to be delivered to wound site 114 may be determined, the healing process of wound site may be tracked, etc. According to various embodiments, controller 118 may be configured to enable the execution of these processes with minimal user intervention and / or input.

[0080] According to various embodiments, the treatment device 102 may include a variety of sensors. For example, in some embodiments, the treatment device 102 may include pressure sensors 115a and / or 115b, which are located in series in the upstream tube section 110a and / or the downstream tube section 110b and are configured to measure the pressure at the removal fluid tank 106 and / or the wound site 114. The pressure measurements recorded by the pressure sensors 115a and / or 115b may be transmitted to a controller 118. According to various embodiments, the controller 118 may use the pressure measurements from the pressure sensors 115a and / or 115b as inputs to various pressure testing operations and control operations performed by the controller 118.

[0081] In some implementations, the treatment device 102 includes a user interface 126. The user interface 126 may include one or more buttons, dial pads, sliders, keypads, or other input devices configured to receive input from a user. The user interface 126 may also include one or more display devices (e.g., LED, 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 alarms generated by the controller 118. For example, if the canister 106 is not detected, the controller 118 may generate a "canister-less" alarm.

[0082] In some embodiments, the therapeutic device 102 includes a data communication interface 124 (e.g., a USB port, a wireless transceiver, etc.) configured to receive and transmit data. The communication interface 124 may include a wired or wireless communication interface (e.g., a jack, antenna, transmitter, receiver, transceiver, wire terminal, etc.) for data communication with external systems or devices. In various embodiments, communication may be direct (e.g., local wired or 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 a port 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 or a cellular or mobile phone transceiver for communication via a wireless communication network.

[0083] How to use

[0084] See Figure 5 A flowchart of a method 500 using an NPWT system 100 according to an exemplary embodiment is shown. (See also...) Figures 6A to 6G The initial setup of the NPWT system 100 and the delivery of an initial amount of infusion fluid 105 to the wound site 114 being treated by the NPWT system 100 will be discussed in more detail in step 502.

[0085] As shown in step 504, according to various embodiments, it may be desirable to deliver additional infusion fluid 105 to wound site 114 after the initial amount of infusion fluid 105 has been infused into wound site 114. It should be understood that determining at step 504 when and whether additional infusion fluid 105 is delivered to wound site 114 can be based on any number of various factors, including, for example, the actual time elapsed since the last infusion, the type of wound site 114, the procedures required for wound site 114 treatment, sensing conditions associated with wound site 114, etc., and can be automatically determined by controller 118 or based on user input.

[0086] If it is determined at step 504 that additional fluid needs to be delivered, then at step 506, a dead space 119 at the wound site 114 is determined according to any of the methods described below. According to various embodiments (described in more detail below), at step 506, the controller 118 may be configured to determine the dead space at the wound site 114 prior to the delivery of such additional infusion fluid 105, regardless of whether the amount of infusion fluid 105 previously infused to the wound site 114 is known; whether there is unabsorbed infusion fluid 105 and / or wound exudate in the space defined between the wound site 114 and the sterile drape layer 117; whether the volume of any contents 107 of the removal fluid canister 106, the volume of the removal fluid canister 106 itself, and / or the volume of any contents 107 previously emptied from the removal fluid canister 106 is known; whether the removal fluid canister 106 has been replaced with a different size removal fluid canister 106 during NPWT treatment; changes in the shape / size / volume of the wound site 114; and so on.

[0087] At step 508, the amount of additional infusion fluid 105 to be delivered to wound site 114 is calculated. According to various embodiments, the amount of additional infusion fluid 105 delivered to wound site 114 may be based on the volume of the dead space determined at step 506. For example, in some embodiments, the controller 118 may calculate the volume of infusion fluid 105 to be delivered to wound site 114 by multiplying the volume of the dead space determined at step 506 by a fluid infusion factor. The fluid infusion factor may be equal to or less than one (i.e., between zero and one) such that the volume of infusion fluid 105 delivered to wound site 114 does not exceed the available space (i.e., the dead space) within the sterile drape layer 117, thereby minimizing the risk of accidental leakage from wound dressing 112 / sterilized drape layer 117. In some embodiments, the fluid infusion factor is between about 0.2 and about 0.8.

[0088] In addition to being used to calculate the volume of the infusion fluid 105, in some embodiments, the NPWT may be used, either otherwise or alternatively, to monitor and track the healing progress of the wound site 114 over time. Therefore, in some embodiments, method 500 may optionally include step 510 of estimating the volume of the wound site 114 and using the estimated volume to track the healing progress of the wound site 114, as described below. Figure 11 Let's discuss this in more detail.

[0089] In some embodiments, it may be desirable to remove the previously infused fluid 105 from the wound site 114 at some point after the infusion fluid 105 has been delivered to the wound site 114. Therefore, it may be advantageous to confirm, before infusing the infusion fluid 105 into the wound site 114, that the empty cavity in the removal fluid container 106 will be sufficient to accommodate the infusion fluid 105 removed from the wound site 114 and / or any additional fluid 121 (e.g., wound exudate), before delivering additional infusion fluid 105 to the wound site 114. Thus, method 500 may optionally include step 512, in which the volume of additional infusion fluid 105 calculated at step 508 is compared with the empty cavity of the removal fluid container 106 (e.g., the empty cavity measured during the determination of the empty cavity at the wound site 114 at step 506), wherein if the infusion fluid 105 to be delivered exceeds the empty cavity of the removal fluid container 106, an alarm is issued to the user at step 514. If the infusion fluid 105 to be delivered does not exceed the dead space of the fluid removal vessel 106 (or if step 512 is not included as part of method 500), the calculated infusion fluid 105 is delivered to the wound site 114, wherein some or all of steps 504, 506, 508, 510, 512, 514, and 516 are repeated any number of additional times during the NPWT treatment.

[0090] See Figure 6A The diagram shows a flowchart of the steps of a detailed method 600 according to one embodiment, which is used for the initial setup of an NPWT system 100 and for delivering an initial amount of drip fluid 105 to... Figure 5 The wound site 114 required in step 502 of method 500. At step 602, an NPWT system 100 (such as, for example...) is provided. Figure 1 (As illustrated), the sterile drape 117 and the wound dressing 112 are positioned at the desired wound site 114 to be treated, such as, for example... Figure 6B As shown.

[0091] Once the NPWT system 100 is set up at step 502, step 604 begins to determine the available dead space 119 at the wound site 114 where the infusion fluid 105 can be delivered, wherein the controller 118 operates the pneumatic pump 120 to establish a first desired negative pressure throughout the negative pressure loop 200, such as, for example Figure 6C exemplified.

[0092] In embodiments where valve 111 includes a normally closed pressure-sensitive valve capable of opening in response to an applied predetermined threshold negative pressure, the first desired negative pressure generated by controller 118 at step 604 may be equal to or greater than the predetermined threshold pressure required to open valve 111, in order to ensure that the vacuum applied by pneumatic pump 120 is applied throughout the negative pressure circuit 200. In some embodiments, the threshold pressure required to open valve 111 may be a pressure of approximately -125 mmHg, wherein controller 118 is configured to apply a first negative pressure equal to or greater than -125 mmHg at step 604.

[0093] Alternatively, in embodiments where the opening / closing of valve 111 is controlled manually or directly in response to a signal from controller 118, the negative pressure delivered at step 604 may typically include any desired range of negative pressure, wherein step 604 includes verification by the user and / or controller that valve 111 is in an open flow orientation prior to the application of negative pressure by pneumatic pump 120. For example... Figure 6C As illustrated, according to various embodiments, the drip valve 109 and the vent valve 113b can be configured to be closed during the application of negative pressure to the negative pressure circuit 200.

[0094] like Figure 6D As illustrated, at step 606, after a first desired negative pressure is reached within the negative pressure circuit 200 (e.g., a negative pressure measured and reported to the controller 118 by pressure sensors 115a and / or 115b, for example), operation of the pneumatic pump 120 is stopped, and the exhaust valve 113b is opened to allow air from the surrounding environment of the treatment device 102 to flow through the exhaust port 113a and into the negative pressure circuit 200. According to various embodiments, opening the exhaust valve 113b at step 606 can be done manually by the user or in response to an instruction from the controller 118. In other embodiments, the graded leakage system 113 can be formed without the exhaust valve 113b (i.e., the exhaust port 113a defines a constant leakage rate within the tube 110), such that air from the surrounding environment of the treatment device 102 will flow into the negative pressure circuit 200 without any user and / or controller 118 intervention.

[0095] As air from the surrounding environment flows into the negative pressure circuit 200, parameters related to the airflow entering the negative pressure circuit 200 through the exhaust port 113a (e.g., via flow detector 113c, pressure sensor 115a, pressure sensor 115b, etc.) are monitored, wherein the measured parameters are then used by the controller 118 at step 612 to determine the volume of the negative pressure circuit 200. According to various embodiments, the parameters related to the airflow entering the negative pressure circuit 200 may include, for example: the rate of airflow entering the negative pressure circuit 200 (e.g., measured by flow detector 113c); the duration required for the pressure within the negative pressure circuit 200 to increase to a predetermined pressure (ambient pressure) after the exhaust port 113a is opened and / or after the operation of the pump 120 is stopped; the changing pressure within the negative pressure circuit 200 (e.g., measured by pressure sensor 115a and / or pressure sensor 115b) as the pressure increases from the negative pressure applied at step 604 to the predetermined pressure, etc.

[0096] Once the pressure within the negative pressure circuit 200 increases to the desired pressure and the controller 118 has completed the measurement of the desired parameters, the controller 118 can be configured to operate the pneumatic pump 120 to establish a second desired negative pressure in the removal fluid tank circuit 202 portion of the negative pressure circuit 200 at step 608, such as, for example... Figure 6E As illustrated, in embodiments where valve 111 includes a normally closed pressure-sensitive valve capable of opening in response to an applied predetermined threshold negative pressure, the second desired negative pressure generated by controller 118 at step 608 may be less than the predetermined threshold pressure required to open valve 111, in order to ensure that the vacuum applied by pneumatic pump 120 at step 608 is applied only to the removal fluid tank circuit 202 portion of negative pressure circuit 200. For example, in some embodiments, the threshold negative pressure required to open valve 111 may be approximately -125 mmHg, wherein controller 118 is configured to apply a negative pressure less than -125 mmHg at step 608, such as, for example, a pressure of approximately -50 mmHg.

[0097] Alternatively, in embodiments where the opening / closing of valve 111 is controlled manually or directly in response to a signal from controller 118, the negative pressure delivered at step 608 may typically include any desired range of negative pressure, wherein step 608 includes verification by the user and / or controller that valve 111 is in a closed, non-flow orientation prior to the application of negative pressure by pneumatic pump 120. It should be understood that in such embodiments, the second negative pressure applied by controller 118 to the removal fluid tank circuit 202 at step 608 may include a pressure equal to or different from the negative pressure applied by controller 118 to the negative pressure circuit 200 at step 604. For example... Figure 6EAs illustrated, according to various embodiments, the drip valve 109 and the vent valve 113b may be configured to be in a closed configuration during the application of negative pressure to the fluid removal tank circuit 202 at step 608.

[0098] like Figure 6F As illustrated, at step 610, after a second desired negative pressure is reached within the removal fluid tank circuit 202 (e.g., a negative pressure measured and reported to the controller 118 by pressure sensors 115a and / or 115b), operation of the pneumatic pump 120 is stopped, and air from the surrounding environment of the treatment device 102 is allowed to flow through the vent 113a and into the removal fluid tank circuit 202. As air from the surrounding environment flows into the removal fluid tank circuit 202, parameters related to the airflow through the vent 113a and into the removal fluid tank circuit 202 are monitored, and the volume of the removal fluid tank circuit 202 is subsequently calculated by the controller 118 using the measured parameters at step 612. According to various embodiments, parameters related to the airflow entering the removal fluid tank circuit 202 may include, for example: the rate of airflow entering the removal fluid tank circuit 202 (as measured, for example, by flow detector 113c); the duration required for the pressure within the removal fluid tank circuit 202 to increase to a predetermined pressure (e.g., ambient pressure) after the vent 113a is opened and / or the operating pump 120 is stopped at step 610; the pressure within the removal fluid tank circuit 202 as the pressure increases from the negative pressure applied at step 608 to the predetermined pressure (as measured, for example, by pressure sensor 115a and / or pressure sensor 115b), etc.

[0099] At step 612, controller 118 may be configured to determine the volumes of the removed fluid tank loop 202 and the negative pressure loop 200 based on the parameters measured at steps 606 and 610. According to some embodiments, controller 118 may cause these volumes to be calculated based on relationships between various stored measured parameter values ​​and corresponding volumes. These relationships between the measured parameter values ​​and the corresponding volumes stored by controller 118 may include various functions, models, lookup tables, etc., and may be based on existing information input to and stored by controller 118, or on information acquired and processed by controller 118 during optional initial training performed by controller 118 before using the NPWT system 100 to treat wound site 114 (e.g., before initiating method 500; as part of the initial setup and initial infusion of the infusion fluid in step 502, etc.). A non-limiting example of an implementation of a training process that the controller 118 may use to generate such relationships is outlined in related co-pending U.S. Provisional Application 62 / 650,132 entitled “WOUND THERAPY SYSTEM WITH WOUND VOLUME ESTIMATION”, filed April 17, 2018, the entire disclosure of which is incorporated herein by reference.

[0100] Using the determined volumes of the removal fluid canister circuit 202 and the negative pressure circuit 200, the controller 118 can determine the volume of the void cavity 119 at the wound site 114 (i.e., the portion of the internal space defined between the wound site 114 and the lower surface of the sterile drape layer 117 that is not occupied by the wound dressing 112 and / or any infusion fluid 105 / other fluid) by subtracting the volume of the removal fluid canister circuit 202 from the volume of the negative pressure circuit 200. According to various embodiments, determining the volume of the void cavity 119 at the wound site 114 at step 614 may also include subtracting or otherwise adjusting the calculated difference between the volume of the removal fluid canister circuit 202 and the volume of the negative pressure circuit 200 to take into account / incorporate the known volume of the downstream tubing portion 110b and the known volume of the portion of the downstream infusion tubing 108b extending between the sterile drape layer 117 and the infusion valve 109 in the determination of the volume of the void cavity 119 at the wound site 114.

[0101] At step 614, the initial amount of infusion fluid 105 to be delivered to wound site 114 is calculated. According to various embodiments, the calculated initial amount of infusion fluid 105 to be delivered to wound site 114 may be based on the volume of the dead space 119 calculated by controller 118 at step 612. For example, in some embodiments, controller 118 may calculate the initial volume of infusion fluid 105 to be delivered to wound site 114 by multiplying the volume of the dead space 119 calculated at step 612 by a fluid infusion factor. The fluid infusion factor may be equal to or less than one (i.e., between zero and one) such that the volume of infusion fluid 105 delivered to wound site 114 does not exceed the available space within the sterile drape layer 117, thereby reducing accidental leakage from wound dressing 112 / sterilized drape layer 117. In some embodiments, the fluid infusion factor is between about 0.2 and about 0.8. However, it is contemplated that the fluid infusion factor may have any value in various alternative embodiments.

[0102] As described above with reference to step 510, in addition to calculating the amount of infusion fluid 105 to be delivered during any treatment phase using the NPWT system 100 and under any number of different conditions (e.g., allowing the calculation of additional infusion fluid 105 to be delivered at step 516 even if the removal fluid canister 106 has been emptied or completely replaced with a removal fluid canister 106 of a different size during treatment), in some embodiments, the NPWT system 100 may, in addition to or alternatively, be used to monitor and track the healing progress of the wound site 114 over time. Therefore, in some embodiments, at step 616, the initial baseline volume estimate of the wound site 114 may optionally be determined by the controller 118 (via, for example, referenced below). Figure 11 The method described above is used to store the estimated value, which can be used as a reference point. The estimated volume of the future wound site 114 can be compared with the reference point to track the healing process of the wound site 114.

[0103] Based on reference Figure 5For similar reasons as described in step 512 of method 500, according to some embodiments, at step 618, the amount of initial infusion fluid 105 to be delivered, calculated at step 614, can be compared with a determined empty cavity 103 in the removal fluid container 106 to determine whether the empty cavity within the removal fluid container 106 will be sufficient to collect any fluid 121 (including unabsorbed infusion fluid 105) from the wound site 114 after delivery of the infusion fluid 105 at step 516. It should be understood that in embodiments where the NPWT system 100 has not been run before its use at step 602, the volume of the removal fluid container 106 should be empty such that the empty cavity 103 of the removal fluid container 106 should be equal to the volume of the removal fluid container 106. If the volume of the removed fluid canister 106 is unknown at step 602 and / or if the removed fluid 107 is present in the removed fluid canister 106, the dead space 103 of the removed fluid container can be calculated by subtracting the known volumes of the conduit 136 and the upstream tube portion 110a from the volume of the removed fluid canister circuit 202 determined at step 614. Similar to step 514, at step 620, if the initial volume of the infusion fluid 105 to be delivered calculated at step 614 exceeds the dead space 103 of the removed fluid canister 106, an alarm can be issued to the user. Otherwise, if the initial volume of the infusion fluid 105 to be delivered does not exceed the dead space 103 of the removed fluid canister 106, the calculated infusion fluid 105 is delivered to the wound site 114 in step 622, for example... Figure 6F As shown.

[0104] See Figure 7 This illustrates an NPWT system 100 according to one embodiment in determining... Figure 5 Method 500 describes a situation where, in step 504, additional infusion fluid 105 is infused into the wound site 114, but before step 506, the time point before determining the wound dead space at the wound site is considered. For example... Figure 7 As shown, immediately before the determination of the dead space at wound site 114 in step 506, a certain amount of fluid 121 (e.g., unabsorbed infusion fluid 105 from a previous infusion, wound exudate, etc.) may exist in the space between the sterile drape layer 117 and the wound site 114, wherein the remaining space between the sterile drape layer 117 and the wound site 114 defines the initial dead space 119a. Similarly, as... Figure 7As shown, according to some embodiments, an initial amount of removal fluid 107 may be present in the removal fluid reservoir 106 immediately preceding the start of step 506, wherein the remaining volume of the removal fluid reservoir 106 is defined by the initial empty cavity 103a. It should be understood that, according to some embodiments, fluid may be absent at the wound site 114 and / or in the removal fluid reservoir 106 immediately preceding step 506; in these embodiments, the amount of each of the fluid 121 in the wound space and the removal fluid 107 in the removal fluid reservoir 106 will be equal to zero.

[0105] As described above, immediately prior to the initiation of step 506, a certain amount of fluid 121 may be present at the wound site 114. According to some embodiments, in Figure 5 Before delivering additional infusion fluid 105 to wound site 114 at step 516 of method 500, it may be undesirable and / or unnecessary to remove fluid 121 from wound site (e.g., unabsorbed infusion fluid 105 from previous infusions, wound exudate, etc.). Therefore, in some embodiments of method 500, additional infusion fluid 105 that was infused to wound site at step 516 may be delivered to wound site 114 regardless of any fluid 121 that may be present at wound site 114.

[0106] See Figures 8A to 8E An embodiment of method 800 for determining the amount of dead space at wound site 114 is illustrated. Figure 5 At step 506 of method 500, the method can be used in embodiments where fluid 121 in wound site 114 is not removed from wound site 114 before additional infusion fluid 105 is administered. Specifically, according to Figures 8A to 8E In method 800, since no fluid 121 is drained from the wound site 114 during method 800 (i.e., step 506), the final dead space into which additional fluid 121 will be dripped will be the same initial dead space 119a at the wound site that existed immediately before the initiation of step 506 (i.e., Figure 7 The invalid cavity 119a is shown.

[0107] like Figure 8A The flowchart shows the method 800 for determining the dead space and the method 600 for calculating the dead space 119 after initially infusing the infusion fluid 105 to the wound site 114 at step 502 (see the flowchart). Figures 6A to 6G (For a more detailed discussion) They are essentially the same. Specifically, they are similar to steps 604 and 606. Figure 8A Method 800 also includes steps 802 and 804 (e.g., respectively in...) Figure 8B and Figure 8CAs shown in the diagram, during these steps, negative pressure is applied to and removed from the negative pressure circuit 200. Similar to... Figure 6A Steps 608 and 610 of method 600 Figure 8A Method 800 also includes steps 806 and 808 (e.g., respectively in...) Figure 8D and Figure 8E As shown in the diagram, during these steps, a negative pressure is applied to and removed from the fluid removal tank circuit 202. This is also similar to... Figure 6A Method 600, in Figures 8A to 8E In method 800, the step 802 of applying negative pressure to negative pressure circuit 200 and the subsequent step 804 of removing negative pressure may be performed before or after the step 806 of applying negative pressure to fluid removal tank circuit 202 and the subsequent step 808 of removing negative pressure.

[0108] As mentioned above, Figures 8A to 8E Method 800 can be referenced above. Figure 6A The method described in 600 is essentially the same. However, as referred to above... Figures 6A to 6E According to the method described, in various embodiments, any range of negative pressure can generally be applied to the negative pressure circuit 200 at step 604 of method 600, but the negative pressure applied to the negative pressure circuit 200 at step 802 of method 800 must be limited to a negative pressure that will not cause the fluid 121 at wound site 114 to be drained into the removal fluid tank 106.

[0109] After completing step 808, controller 118 can be configured to... Figure 5 At step 508 of method 500, the volume of the dead space 119a at wound site 114 is calculated (which corresponds to the maximum volume of additional drip fluid 105 that can be delivered to wound site 114). More specifically, at step 508, the volumes of the removal fluid tank circuit 202 and the negative pressure circuit 200 are calculated based on parameters measured at steps 804 and 808 (in a manner similar to reference). Figures 6A to 6G Following step 612 of method 600, the dead space 119a at the wound site 114 can be calculated by subtracting the measured volume of the removal fluid tank circuit 202 from the measured volume of the negative pressure circuit 200. Figures 8A to 8EThe volume of the fluid removal tank circuit 202 of method 800 is defined by the following: the dead space 103a of the fluid removal tank 106, the conduit 136 and the upstream tube portion 110a; and the volume of the negative pressure circuit 200 is defined by the following: the volume of the fluid removal tank circuit 202 (i.e., the volume of the dead space 103a, the conduit 136 and the upstream tube portion 110a of the fluid removal tank 106), the downstream tube portion 110b, the dead space 119a of the wound site 114, and the portion of the downstream drip tube 108b extending between the sterile drape layer 117 and the drip valve 109.

[0110] According to various implementation schemes, in an implementation of method 500, the volume of the dead space 119a at the wound site 114 determined in step 508 is based on the use of Figures 8A to 8E The method 800 obtains measurement parameters related to the removal fluid tank circuit 202 and the negative pressure circuit 200. Step 508 may also include subtracting or otherwise adjusting the calculated difference between the volume of the removal fluid tank circuit 202 and the volume of the negative pressure circuit 200 in order to take into account the known volume of the downstream tubing portion 110b and the known volume of the portion of the downstream drip tube 108b extending between the sterile cover layer 117 and the drip valve 109 in the determination of the volume of the dead space 119a at the wound site 114.

[0111] Although, as described above, in some embodiments of method 500, it is not necessary to first remove any remaining fluid 121 at wound site 114 before delivering additional infusion fluid 105 at step 516, according to other embodiments, it may be desirable to remove fluid 121 from wound site 114 before delivering additional infusion fluid 105.

[0112] See Figures 9A to 9E An embodiment of a method 900 for determining the amount of dead space at wound site 114 is shown. Figure 5 At step 506 of method 500, this method can be used in embodiments where it is desired to remove fluid 121 from wound site 114 before administering additional fluid 105. Specifically, according to Figures 9A to 9E In method 900, during method 900 (i.e., step 506), any fluid 121 that was present at the wound site 114 immediately prior to step 506 (e.g., such as...) Figure 7 As shown, the fluid is drained from the wound site 114, such that the final dead space 119b into which additional drip fluid 121 will be dripped will be larger than the initial dead space 119a at the wound site immediately prior to the initiation of step 506 by approximately the volume of fluid 121 drained from the wound site 114 into the removal fluid canister 106 during method 900.

[0113] like Figure 9A The flowchart shows the method 900 for determining the dead space and the method 600 for calculating the dead space 119 after initially infusing the infusion fluid 105 to the wound site 114 at step 502 (see [reference]). Figures 6A to 6G (For a more detailed discussion) They are essentially the same. Specifically, they are similar to steps 604 and 606. Figure 9A Method 900 also includes steps 902 and 904 (e.g., respectively in...) Figure 9B and Figure 9C As shown in the diagram, during these steps, negative pressure is applied to and removed from the negative pressure circuit 200. Similar to... Figure 6A Steps 608 and 610 of method 600 Figure 9A Method 900 also includes steps 906 and 908 (e.g., respectively in...) Figure 9D and Figure 9E (as shown in the figure) During these steps, a negative pressure is applied to the fluid removal tank circuit 202 and the negative pressure is removed from the fluid removal tank circuit.

[0114] However, with Figure 6A The method differs from method 600, in which step 604 of applying negative pressure to negative pressure circuit 200 and step 608 of subsequently removing negative pressure can be performed before or after step 610 of applying negative pressure to removal fluid tank circuit 202 and step 612 of subsequently removing negative pressure. Figure 9A In method 900, the steps 902 of applying negative pressure to the negative pressure circuit 200 and 904 of subsequently removing the negative pressure are performed before the steps 906 of applying negative pressure to the fluid removal tank circuit 202 and 908 of subsequently removing the negative pressure. Additionally, although as described above... Figures 6A to 6E As described in the method, according to various embodiments, a negative pressure of any range can typically be applied to the negative pressure circuit 200 at step 604 of method 600, but... Figure 9A In step 902 of method 900, the negative pressure applied to the negative pressure circuit 200 must be sufficient to cause fluid 121 to drain from the wound site 114 into the removal fluid tank 106.

[0115] After completing step 908, controller 118 can be configured to... Figure 5 At step 508 of method 500, the volume of the final dead space 119b at wound site 114 is calculated (which corresponds to the maximum volume of additional drip fluid 105 that can be delivered to wound site 114). More specifically, at step 508, the volumes of the removal fluid tank circuit 202 and the negative pressure circuit 200 are calculated based on parameters measured at steps 904 and 908 (in a manner similar to reference). Figures 6A to 6GFollowing step 612 of method 600, the final dead space 119b at the wound site 114 can be calculated by subtracting the measured volume of the removal fluid tank circuit 202 from the measured volume of the negative pressure circuit 200. Figures 9A to 9E The volume of the fluid removal tank circuit 202 in method 900 is defined by the following: the final empty cavity 103b of the fluid removal tank 106 (wherein, at step 802, the final empty cavity 103b of the fluid removal tank 106 is approximately equal to the difference between the initial empty cavity 103a within the fluid removal tank 106 and the volume of fluid 121 drained from the wound site 114 into the fluid removal tank 106, such as, for example...). Figure 9B (as shown), conduit 136 and upstream tube portion 110a; and the volume of the negative pressure circuit 200 is defined by the following: the volume of the fluid removal tank circuit 202 (i.e., the final dead space 103b of the fluid removal tank 106, conduit 136 and upstream tube portion 110a), the downstream tube portion 110b, the final dead space 119b of the wound site 114, and the portion of the downstream drip tube 108b extending between the sterile cover layer 117 and the drip valve 109.

[0116] According to various implementation schemes, in an implementation of method 500, the volume of the dead space 119 at the wound site 114 determined in step 508 is based on the use of Figures 9A to 9E The method 900 obtains measurement parameters related to the removal fluid tank circuit 202 and the negative pressure circuit 200. Step 508 may also include subtracting or otherwise adjusting the calculated difference between the volume of the removal fluid tank circuit 202 and the volume of the negative pressure circuit 200 in order to take into account the known volume of the downstream tubing portion 110b and the known volume of the portion of the downstream drip tube 108b extending between the sterile cover layer 117 and the drip tube valve 109 in the determination of the volume of the dead space 119a at the wound site 114.

[0117] exist Figure 5 In some embodiments of method 500, where fluid 121 in wound site 114 is removed before additional infusion fluid 105 is infused at step 516, it may be desirable to ensure that the initial void 103a in fluid canister 106 is sufficient to hold fluid 121 that will be drained from wound site 114 into fluid canister 106 during step 506 immediately before the step of determining void cavities at wound site 506 is initiated, in order to avoid the risk of fluid canister 106 overflowing.

[0118] Therefore, in some embodiments of method 500, the method of step 506, which involves removing fluid 121 from wound site 114 prior to instilling any additional fluid 105 at step 516, and determining the dead space at wound site 114 (e.g., as described in reference...), is used to... Figures 9A to 9EThe method described in 900 may include determining whether there is a sufficient dead space at the removal fluid tank 106 to hold fluid 121 from the wound site 114 and which can be drained into the removal fluid tank 106, as part of the method for determining the dead space at the wound site 114.

[0119] Figures 10A to 10C An embodiment of such a method is illustrated, which can be used in step 506 (e.g. via a method such as...) to locate the dead space at the correct wound site 114. Figures 9A to 9E The method (900) minimizes the risk of overflow from the fluid tank 106 during removal of fluid. At steps 1002 and 1004 (as described respectively...) Figure 10B and Figure 10C As shown), a negative pressure is applied to and removed from the fluid removal tank circuit 202 to determine the initial dead space 103a in the fluid removal tank 106 before starting step 506 (e.g., as shown). Figure 7 (As shown). Generally speaking, Figures 10A to 10C Steps 1002 and 1004 of method 1000 can be combined with Figures 6A to 6G Steps 608 and 610 of method 600 are performed in a substantially similar manner. At step 1006, the volume of fluid tank loop 202 to be removed is calculated based on the parameters measured at step 1004 (in a manner similar to reference). Figures 6A to 6G (as described in step 612 of method 600). Once the volume of the removal fluid tank circuit 202 is calculated, the known volumes of the conduit 136 and the upstream tube portion 110a can be subtracted from the calculated removal fluid tank circuit 202 to determine the volume of the initial dead space 103a in the removal fluid tank 106 (i.e., the maximum volume of fluid 121 discharged from the wound site 114 that the removal fluid tank 106 can hold).

[0120] Once the volume of the initial invalid cavity 103a is calculated at step 1006, at step 1008, the controller 118 can be configured to estimate the volume of fluid 121 at wound site 114 immediately preceding the determination of the invalid cavity at wound site 114 at step 506. The volume of fluid 121 at wound site 114 can be based on any number of different factors and variables, such as, for example, the stored value of the amount of infusion fluid 105 previously delivered to wound site 114, the stored value of fluid 121 previously removed from wound site, the elapsed time (e.g., elapsed time since the last infusion, elapsed time since the last removal of fluid 121, etc.), etc., wherein at step 1008, the controller 118 is also configured to compare this estimated volume of fluid 121 with the initial invalid cavity 103a calculated at step 1006, and if the controller 118 determines that the estimated volume of fluid 121 exceeds the calculated initial invalid cavity 103a, then at step 1010, the user is alerted to empty the removal fluid tank 106. If the calculated initial invalid cavity 103a is sufficient to hold the estimated volume of fluid 121 from the wound site 114, then at step 1012, the controller 1012 may be configured, for example, according to reference... Figures 9A to 9E The method 900 begins with step 506 of determining the invalid cavity at the wound site 114.

[0121] As described above, according to some embodiments of method 500, it may be advantageous to monitor the volume change of wound site 114 at optional step 510 to track the healing progress of wound site 114.

[0122] Generally, the volume of the wound site 114 is defined by its entire interior, which extends between the wound site 114 and the sterile drape layer 117 surrounding the wound site 114 and attached to the skin 116. At various points during treatment using the NPWT system 100, the volume of the wound site defined by it may be any and any combination of the wound dressing 112, the fluid 121, and / or the dead space 119. It should be understood that unless the wound dressing 112 is changed during treatment, the volume of the wound site 114 occupied by the wound dressing 112 will generally remain constant during treatment, while the portion of the volume of the wound site 114 occupied by the fluid 121 and / or the dead space 119 may change over time.

[0123] See Figure 11 A block diagram is shown, illustrating what can be done... Figure 5This is one embodiment of method 1100, used in step 510 of method 500 to track the healing progress of wound site 114. At step 1102, at a time point prior to the initial infusion of infusion fluid 105 into wound site 114, the controller 118 estimates and records the initial volume of wound site 114, and this initial volume can be used as a baseline compared with subsequent volume estimates of wound site 114 to track the healing progress. According to various embodiments, the estimate of the initial volume of wound site 114 made at step 1102 can be based on (or used as) a reference. Figures 6A to 6G Step 616 of method 600 is performed.

[0124] At step 1104, after estimating the initial volume of wound site 114 at step 1102, the estimated volume of wound site 114 is determined and recorded at one or more additional times during treatment (e.g., once daily), wherein the time at which such one or more wound sites 114 volumes are estimated, and the determined volume values ​​of wound sites 114, are stored as data points in the memory of treatment device 102 and / or presented to the user as output of treatment device 102 (e.g., via communication interface 124 or user interface 126). In some embodiments, the estimated wound volume may be plotted as a function of time.

[0125] At step 1104, additional wound site 114 volume estimates determined at one or more additional times during the treatment can be estimated based on any number of different processes. For example, according to some embodiments, the wound site 114 volume estimate recorded at step 1104 can be based on the final dead space volume at the wound site 114, which, for example, refers to... Figure 5 Method 500, step 508, is used to calculate, and / or reference is used as follows: Figures 9A to 9E The method described is used to calculate 900.

[0126] like Figure 5 Step 510 and Figure 6A As shown in step 616, according to some embodiments, the volume estimation of the wound site 114 at steps 1102 and / or 1104 may be performed in conjunction with the method of delivering the infusion fluid 105 to the wound site 114. However, it should be understood that, according to other embodiments, the determination and recording of some, all, or zero volume estimates of the wound site 114 at steps 1102 and / or 1104 may be performed independently of any delivery of the infusion fluid 105 to the wound site 114.

[0127] Since an additional volume estimate of wound site 114 was obtained at step 1104, the estimated change in volume of wound site 114 over time can be used at step 1106 to determine the healing progress of wound site 114. For example, step 1106 may include comparing the volume estimate of wound site 114 obtained at step 1104 with one or more previous estimates of the volume of wound site 114 (estimates obtained at step 1104 or step 1102) to identify changes in the volume of wound site 114. In some embodiments, step 1006 may also include determining the rate of healing of wound site 114 based on the estimated change in volume of wound site 114 over time. In some embodiments, step 1106 may include extrapolating or predicting the time it will take for wound site 114 to fully heal based on a series of wound site 114 volume estimates stored in controller 118. For example, step 1106 may include predicting the time when the estimated wound site 114 volume will reach zero (or another threshold) based on the initial wound site 114 volume estimate obtained at step 1002 and a series of additional wound site 114 volume estimates obtained at step 1004.

[0128] It should be understood that, according to various embodiments, the controller 118 can be programmed to allow the NPWT system 100 to determine the volume relative to the wound site 114 using any or all of the methods described herein. Therefore, while in some embodiments the controller 118 may optionally be pre-programmed to suit specific methods (e.g., Figures 9A to 9E The method 900 embodiment shown automatically determines the volume of the infusion fluid 105 to be delivered. The controller 118 may also optionally allow the user to: select any of other modes of calculating the volume relative to the wound site 114 based on whether the user wishes, for example, to remove fluid 121 from the wound site 114 before infusing additional infusion fluid 105; verify whether it is sufficient to remove the invalid cavity 103a in the fluid canister 106 before determining the invalid cavity at the wound site 114; verify whether it is sufficient to remove the invalid cavity 103b in the fluid canister 106 before infusing an additional infusion fluid 105 of the calculated amount to be delivered to the wound site 114; monitor changes in the volume of the wound site 114 to track the healing process; and so on.

[0129] Configuration of exemplary implementation

[0130] The construction and arrangement of the systems and methods illustrated in the various exemplary embodiments are merely illustrative. 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 proportions of various components, parameter values, installation arrangements, use of materials, color, orientation, etc.). For example, the positions of components may be reversed or otherwise changed, and the nature, number, or location of discrete components may be altered or changed. Therefore, all such modifications are intended to be included within the scope of this disclosure. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. Other substitutions, modifications, alterations, and omissions may be made to the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of this disclosure.

[0131] 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, CD-ROM or other optical disc 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.

[0132] Although the accompanying drawings show a specific sequence of method steps, the order of steps may differ from that depicted. Furthermore, two or more steps may be performed simultaneously or partially simultaneously. Such variations will depend on the chosen software and hardware system and the designer's choices. All such variations are within the scope of this disclosure. Similarly, software implementations can be achieved using standard programming techniques with rule-based logic and other logic to implement various connection steps, processing steps, comparison steps, and decision steps.

Claims

1. A treatment device for treating a tissue site, the treatment device having a fluid conduit having a first end connected to a fluid reservoir and a pump of the treatment device and a second end fluidly connected to a wound dressing, the treatment device comprising: The controller is configured to: Operate the pump to apply a first predetermined negative pressure to a first volume including the fluid tank but excluding the wound dressing; The pump is stopped for a period of time, during which the first predetermined negative pressure in the first volume increases to the baseline pressure within the first time period. The first capacity of the first volume is determined using the first time period; Operate the pump to apply a second predetermined negative pressure to a second volume comprising the first volume and the wound dressing; as well as The pump is stopped for a period of time, during which the second predetermined negative pressure in the second volume increases to the baseline pressure in the second time period. The second time period is used to determine the second capacity of the second volume; as well as The amount of fluid to be delivered for the first wound dressing is determined at least in part based on the difference between the first and second capacities.

2. The treatment device according to claim 1, wherein the first predetermined negative pressure is different from the second predetermined negative pressure.

3. The treatment device according to claim 2, wherein the first predetermined negative pressure is greater than the second predetermined negative pressure.

4. The treatment device of claim 1, wherein the valve is operably connected to the fluid tube at a position between the first end and the second end of the fluid tube, the valve forming a first portion between the first end of the fluid tube and the valve, and forming a second portion between the second end of the fluid tube and the valve.

5. The treatment device of claim 4, wherein the valve is configured to prevent flow between the fluid tube and the wound dressing when the valve is subjected to a pressure equal to or greater than the first predetermined negative pressure.

6. The treatment device of claim 5, wherein the valve is configured to allow flow between the first portion of the fluid conduit and the wound dressing when the valve is subjected to the second predetermined negative pressure.

7. The treatment device of claim 1, wherein the controller is further configured to: operate the pump to deliver a drip volume of the first wound dressing to the wound dressing.

8. The treatment device of claim 1, wherein the controller is further configured to: operate the pump to apply the second predetermined negative pressure to the second volume at a time point prior to operating the pump to apply the first predetermined negative pressure to the first volume.

9. The treatment device of claim 7, wherein after the step of delivering the first wound dressing infusion fluid volume to the wound dressing, the controller is further configured to: Operate the pump to apply a third predetermined negative pressure to the first volume; The pump is stopped for a period of time, during which the third predetermined negative pressure in the first volume increases to the second baseline pressure within a third time period. After the pressure in the fluid tube has reached the second baseline pressure, the pump is operated to apply a fourth predetermined negative pressure to the second volume; as well as The pump is stopped for a period of time, during which the fourth predetermined negative pressure in the second volume increases to the second baseline pressure within a fourth time period.

10. The treatment device according to claim 9, wherein the third predetermined negative pressure is greater than the fourth predetermined negative pressure.

11. The treatment device according to claim 9, wherein the third predetermined negative pressure is equal to the first predetermined negative pressure.

12. The treatment device according to claim 11, wherein the fourth predetermined negative pressure is equal to the second predetermined negative pressure.

13. The treatment device of claim 9, wherein the controller is further configured to operate the pump to deliver a second wound dressing infusion fluid volume to the wound dressing.

14. The treatment device of claim 13, wherein the controller is further configured to: operate the pump to apply the fourth predetermined negative pressure to the second volume at a time point prior to operating the pump to apply the third predetermined negative pressure to the first volume.

15. The treatment device of claim 13, wherein the amount of the second wound dressing infusion fluid delivered to the wound dressing is based on a comparison of the third time period and the fourth time period.

16. The treatment device according to claim 15, wherein the relative difference between the first time period and the second time period is greater than the relative difference between the third time period and the fourth time period.

17. The treatment device according to claim 16, wherein the fluid infusion volume of the first wound dressing is greater than the fluid infusion volume of the second wound dressing.

18. The treatment device of claim 17, wherein the fluid tank is empty when the pump is operated to apply the first predetermined negative pressure and when the pump is operated to apply the second predetermined negative pressure, and the fluid tank is at least partially full when the pump is operated to apply the third predetermined negative pressure and when the pump is operated to apply the fourth predetermined negative pressure.

19. The treatment device according to claim 15, wherein the relative difference between the first time period and the second time period is less than the relative difference between the third time period and the fourth time period.

20. The treatment device according to claim 19, wherein the fluid volume of the first wound dressing is less than the fluid volume of the second wound dressing.

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