Wound therapy system with wound volume estimation

Abstract

To provide a wound therapy system configured to estimate a wound volume.SOLUTION: A wound therapy system comprises: a negative pressure circuit configured to apply negative pressure to a wound; a pump fluidly coupled to the negative pressure circuit and operable to control the negative pressure within the negative pressure circuit; a pressure sensor configured to measure the negative pressure within the negative pressure circuit or at the wound; and a controller communicably coupled to the pump and the pressure sensor. The controller is configured to: execute a pressure testing procedure comprising applying a pressure stimulus to the negative pressure circuit; observe a dynamic pressure response of the negative pressure circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor; and estimate a wound volume of the wound based on the dynamic pressure response.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 650,132, filed March 29, 2018, and U.S. Provisional Patent Application No. 62 / 799,241, filed January 31, 2019, the complete disclosures of each of which are incorporated herein by reference in their entirety.

[0002] The present disclosure relates generally to wound therapy systems, and more particularly to wound therapy systems configured to estimate wound volume. [Background technology]

[0003] Negative pressure wound therapy (NPWT) is a type of wound therapy that involves applying negative pressure to a wound site to promote wound healing. Some wound treatment systems use pneumatic pumps to apply negative pressure to the wound to generate the necessary negative pressure and flow. Recent advances in wound healing with NPWT include applying topical fluids to the wound to work in combination with NPWT. However, it can be difficult to determine the appropriate volume of drip fluid to deliver to the wound. In addition, it can also be difficult to accurately monitor and track healing progress over time. Summary of the Invention

[0004] One embodiment of the present disclosure is a wound therapy system including a negative pressure circuit configured to apply a negative pressure to a wound, a pump fluidly coupled to the negative pressure circuit, the pump operable to control the negative pressure in the negative pressure circuit, a pressure sensor configured to measure the negative pressure in the negative pressure circuit or at the wound, and a controller communicatively coupled to the pump and the pressure sensor, the controller configured to perform a pressure test procedure including applying a pressure stimulus to the negative pressure circuit, observe a dynamic pressure response of the negative pressure circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor, and estimate a wound volume of the wound based on the dynamic pressure response.

[0005] In some embodiments, the negative pressure circuit includes a wound dressing sealable to the skin surrounding the wound. In some embodiments, the negative pressure circuit includes at least one of a drip fluid canister that contains a drip fluid for delivery to the wound or a removal fluid canister that contains fluid removed from the wound. In some embodiments, the negative pressure circuit includes tubing that fluidly connects the pump to the wound.

[0006] In some embodiments, the negative pressure circuit includes a wound dressing sealable to the skin surrounding the wound, at least one of a dripping fluid canister containing a drip fluid for delivery to the wound or a removal fluid canister containing fluid removed from the wound, and tubing fluidly connecting the dripping fluid canister or the removal fluid canister to the wound dressing.

[0007] In some embodiments, the controller is configured to operate the pump to establish a negative pressure in the negative pressure circuit, in some embodiments, the test procedure includes operating the pump to establish a negative pressure in the negative pressure circuit and applying a pressure stimulus after the negative pressure is established in the negative pressure circuit.

[0008] In some embodiments, the system includes a valve coupled to the negative pressure circuit, the valve operable to controllably vent the negative pressure circuit. In some embodiments, applying the pressure stimulus includes opening the valve to allow air flow into the negative pressure circuit for a predetermined time period and closing the valve after the predetermined time period has elapsed. In some embodiments, applying the pressure stimulus further includes waiting for another predetermined time period after closing the valve and repeating the opening, closing, and waiting steps until the negative pressure reaches a threshold pressure value. In some embodiments, applying the pressure stimulus further includes operating a pump while the valve is closed to mitigate air leakage into the negative pressure circuit.

[0009] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a purge depth parameter, which is defined as the difference between the measured negative pressure before the valve is opened and the measured negative pressure while the valve is open.

[0010] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a rebound parameter, which is defined as the difference between the measured negative pressure after the valve is closed and the measured negative pressure while the valve is open.

[0011] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a delta parameter, which is defined as the difference between the measured negative pressure before the valve is opened and the measured negative pressure after the valve is closed.

[0012] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a leak rate parameter, which is defined as the rate at which the negative pressure changes while the valve is closed.

[0013] In some embodiments, the wound therapy system includes an orifice located along the negative pressure circuit and configured to allow air to leak into the negative pressure circuit at a known rate.

[0014] In some embodiments, applying the pressure stimulus includes operating a pump to achieve a predetermined negative pressure in the negative pressure circuit and deactivating the pump when the predetermined negative pressure is reached in the negative pressure circuit.

[0015] In some embodiments, estimating wound volume based on the dynamic pressure response includes determining values ​​for one or more parameters characterizing the dynamic pressure response and applying the values ​​of the one or more parameters as inputs to a model defining a relationship between the one or more parameters and wound volume.

[0016] In some embodiments, the model defining the relationship between the one or more parameters and the wound volume is a polynomial approximation model. In some embodiments, the model defining the relationship between the one or more parameters and the wound volume is a neural network.

[0017] In some embodiments, the control device is configured to execute a training procedure including applying a pressure stimulus to a training circuit having a known volume, observe a dynamic pressure response of the training circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor, and generate a model defining a relationship between one or more parameters and wound volume by correlating the known volume with the dynamic pressure response of the training circuit.

[0018] In some embodiments, generating the model further includes repeating the training procedure for a plurality of known volumes, observing a dynamic pressure response of the training circuit for each of the plurality of known volumes, and generating a correlation between the plurality of known volumes and the dynamic pressure response of the training circuit.

[0019] In some embodiments, the controller is configured to perform a pressure test procedure, observe dynamic pressure responses, and estimate wound volume multiple times during wound treatment. The controller can be configured to determine healing progress based on changes in wound volume during wound treatment.

[0020] In some embodiments, the controller can be configured to determine a volume of drip fluid to deliver to the wound based on the estimated wound volume, and to operate the pump to deliver that volume of drip fluid to the wound.

[0021] In some embodiments, the controller is configured to determine a volume of drip fluid to deliver to the wound by multiplying the estimated wound volume by a fluid drip factor. In some embodiments, the fluid drip factor is less than 1 such that less than the total wound volume is filled with drip fluid. In some embodiments, the fluid drip factor is about 0.2 to about 0.8.

[0022] Another embodiment of the present disclosure is a method for estimating wound volume of a wound, the method including applying negative pressure to the wound using a negative pressure circuit, operating a pump fluidly coupled to the negative pressure circuit to control the negative pressure in the negative pressure circuit, measuring the negative pressure in the negative pressure circuit or at the wound, performing a pressure test procedure including applying a pressure stimulus to the negative pressure circuit, observing a dynamic pressure response of the negative pressure circuit to the pressure stimulus using the negative pressure measurement, and estimating wound volume based on the dynamic pressure response.

[0023] In some embodiments, the negative pressure circuit includes a wound dressing sealable to the skin surrounding the wound. In some embodiments, the negative pressure circuit includes at least one of a drip fluid canister that contains a drip fluid for delivery to the wound or a removal fluid canister that contains fluid removed from the wound. In some embodiments, the negative pressure circuit includes tubing that fluidly connects the pump to the wound.

[0024] In some embodiments, the negative pressure circuit includes a wound dressing sealable to the skin surrounding the wound, at least one of a dripping fluid canister containing a drip fluid for delivery to the wound or a removal fluid canister containing fluid removed from the wound, and tubing fluidly connecting the dripping fluid canister or the removal fluid canister to the wound dressing.

[0025] In some embodiments, the method includes operating a pump to establish a negative pressure in the negative pressure circuit. In some embodiments, the test procedure includes operating a pump to establish a negative pressure in the negative pressure circuit and applying a pressure stimulus after the negative pressure is established in the negative pressure circuit.

[0026] In some embodiments, the method includes operating a valve coupled to the negative pressure circuit to controllably vent the negative pressure circuit, hi some embodiments, applying the pressure stimulus includes opening the valve to allow air flow into the negative pressure circuit for a predetermined period of time and closing the valve after the predetermined period of time has elapsed.

[0027] In some embodiments, applying the pressure stimulus further includes waiting another predetermined time after closing the valve and repeating the opening, closing, and waiting steps until the negative pressure reaches a threshold pressure value. In some embodiments, applying the pressure stimulus further includes operating a pump while the valve is closed to mitigate air leakage into the negative pressure circuit.

[0028] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a purge depth parameter, which is defined as the difference between the measured negative pressure before the valve is opened and the measured negative pressure while the valve is open.

[0029] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a rebound parameter, which is defined as the difference between the measured negative pressure after the valve is closed and the measured negative pressure while the valve is open.

[0030] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a delta parameter, which is defined as the difference between the measured negative pressure before the valve is opened and the measured negative pressure after the valve is closed.

[0031] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a leak rate parameter, which is defined as the rate at which the negative pressure changes while the valve is closed.

[0032] In some embodiments, the method includes allowing air to leak into the negative pressure circuit at a known rate through an orifice located along the negative pressure circuit.

[0033] In some embodiments, applying the pressure stimulus includes operating a pump to achieve a predetermined negative pressure in the negative pressure circuit and deactivating the pump when the predetermined negative pressure is reached in the negative pressure circuit.

[0034] In some embodiments, estimating wound volume based on the dynamic pressure response includes determining values ​​for one or more parameters characterizing the dynamic pressure response and applying the values ​​of the one or more parameters as inputs to a model defining a relationship between the one or more parameters and wound volume.

[0035] In some embodiments, the model defining the relationship between the one or more parameters and the wound volume is a polynomial approximation model. In some embodiments, the model defining the relationship between the one or more parameters and the wound volume is a neural network.

[0036] In some embodiments, the method includes performing a training procedure including applying a pressure stimulus to a training circuit having a known volume, observing a dynamic pressure response of the training circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor, and generating a model defining a relationship between one or more parameters and wound volume by relating the known volume to the dynamic pressure response of the training circuit.

[0037] In some embodiments, generating the model further includes repeating the training procedure for a plurality of known volumes, observing a dynamic pressure response of the training circuit for each of the plurality of known volumes, and generating a correlation between the plurality of known volumes and the dynamic pressure response of the training circuit.

[0038] In some embodiments, the method includes performing a pressure testing procedure, observing a dynamic pressure response, and estimating the wound volume multiple times during wound treatment. The method may include determining healing progress based on changes in the wound volume during wound treatment.

[0039] In some embodiments, the method includes determining a volume of drip fluid to be delivered to the wound based on the estimated wound volume, and operating the pump to deliver the volume of drip fluid to the wound.

[0040] In some embodiments, determining the volume of fluid to deliver to the wound comprises multiplying the estimated wound volume by a fluid drip factor. In some embodiments, the fluid drip factor is less than 1 such that less than the total wound volume is filled with dripped fluid. In some embodiments, the fluid drip factor is about 0.2 to about 0.8.

[0041] Another embodiment of the present disclosure is a wound therapy system that includes a negative pressure circuit configured to apply negative pressure to a wound, a canister containing a drip fluid for delivery to the wound, a pump operable to deliver the drip fluid to the wound, a pressure sensor configured to measure the negative pressure in the negative pressure circuit or at the wound, and a controller communicatively coupled to the pump and the pressure sensor, the controller configured to perform a pressure test procedure to estimate a wound volume of the wound, determine a volume of drip fluid to be delivered to the wound based on the estimated wound volume, and operate the pump to deliver the volume of drip fluid to the wound.

[0042] In some embodiments, the controller is configured to determine a volume of drip fluid to deliver to the wound by multiplying the estimated wound volume by a fluid drip factor. In some embodiments, the fluid drip factor is less than 1 such that less than the total wound volume is filled with drip fluid. In some embodiments, the fluid drip factor is about 0.2 to about 0.8.

[0043] In some embodiments, the negative pressure circuit includes a wound dressing sealable to the skin surrounding the wound, hi some embodiments, the negative pressure circuit includes tubing fluidly connecting the canister to the wound dressing.

[0044] In some embodiments, the controller is configured to operate the pump to establish a negative pressure in the negative pressure circuit. In some embodiments, the pressure test procedure includes operating the pump to establish a negative pressure in the negative pressure circuit and applying a pressure stimulus to the negative pressure circuit after the negative pressure is established in the negative pressure circuit.

[0045] In some embodiments, the wound therapy system includes an orifice located along the negative pressure circuit and configured to allow air to leak into the negative pressure circuit at a known rate.

[0046] In some embodiments, the pressure test procedure includes operating a pump to achieve a predetermined negative pressure in the negative pressure circuit, and when the predetermined negative pressure is reached in the negative pressure circuit, deactivating the pump and observing the dynamic pressure response of the negative pressure circuit.

[0047] In some embodiments, the system includes a valve coupled to the negative pressure circuit, the valve operable to controllably vent the negative pressure circuit, hi some embodiments, the pressure test procedure includes opening the valve to allow air flow into the negative pressure circuit for a predetermined period of time and closing the valve after the predetermined period of time has elapsed.

[0048] In some embodiments, the pressure test procedure includes waiting another predetermined time after closing the valve, and repeating the opening, closing, and waiting steps until the negative pressure reaches a threshold pressure value.

[0049] In some embodiments, the pressure test procedure includes applying a pressure stimulus to the negative pressure circuit, observing a dynamic pressure response of the negative pressure circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor, and estimating a wound volume of the wound based on the dynamic pressure response. In some embodiments, the pressure test procedure includes operating the pump while a valve is closed to mitigate air leakage into the negative pressure circuit.

[0050] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a purge depth parameter, which is defined as the difference between the measured negative pressure before the valve is opened and the measured negative pressure while the valve is open.

[0051] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a rebound parameter, which is defined as the difference between the measured negative pressure after the valve is closed and the measured negative pressure while the valve is open.

[0052] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a delta parameter, which is defined as the difference between the measured negative pressure before the valve is opened and the measured negative pressure after the valve is closed.

[0053] In some embodiments, the dynamic pressure response of the negative pressure circuit is characterized by a leak rate parameter, which is defined as the rate at which the negative pressure changes while the valve is closed.

[0054] In some embodiments, estimating wound volume based on the dynamic pressure response includes determining values ​​for one or more parameters characterizing the dynamic pressure response and applying the values ​​of the one or more parameters as inputs to a model defining a relationship between the one or more parameters and wound volume.

[0055] In some embodiments, the model defining the relationship between the one or more parameters and the wound volume is a polynomial approximation model. In some embodiments, the model defining the relationship between the one or more parameters and the wound volume is a neural network.

[0056] In some embodiments, the control device is configured to perform a training procedure including applying a pressure stimulus to a training circuit having a known volume, observe a dynamic pressure response of the training circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor, and generate a model defining a relationship between one or more parameters and wound volume by correlating the known volume with the dynamic pressure response of the training circuit.

[0057] In some embodiments, generating the model further includes repeating the training procedure for a plurality of known volumes, observing a dynamic pressure response of the training circuit for each of the plurality of known volumes, and generating a correlation between the plurality of known volumes and the dynamic pressure response of the training circuit.

[0058] In some embodiments, the controller is configured to perform a pressure testing procedure to estimate wound volume multiple times during wound treatment and to determine healing progress based on changes in wound volume during wound treatment.

[0059] Those skilled in the art will recognize that the summary is merely illustrative and is in no way intended to be limiting. Other aspects, features, and advantages of the apparatus and / or processes described herein, as defined solely by the claims, will become apparent in the detailed description set forth herein and taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0060] [Figure 1] FIG. 1 is a block diagram of a wound therapy system including a therapy device coupled to a wound dressing via a tube, according to an exemplary embodiment. [Diagram 2] FIG. 2 is a block diagram illustrating the therapy device of FIG. 1 in greater detail when the therapy device is operated to draw a vacuum in the negative pressure circuit, according to an exemplary embodiment. [Figure 3A] FIG. 3A is a block diagram illustrating the therapy device of FIG. 1 in greater detail when the therapy device is operated to ventilate the negative pressure circuit, according to an exemplary embodiment. [Figure 3B] FIG. 3B is a block diagram illustrating the therapy device of FIG. 1 in greater detail when the therapy device vents the negative pressure circuit using an orifice, according to an exemplary embodiment. [Figure 4] FIG. 4 is a block diagram illustrating the therapy device of FIG. 1 in greater detail when the therapy device is operated to deliver a drip fluid to a wound dressing and / or wound, according to an exemplary embodiment. [Diagram 5] FIG. 5 is a block diagram illustrating the controller of the therapy device of FIG. 1 in greater detail, according to an exemplary embodiment. [Figure 6A] FIG. 6A is a graph illustrating a passive pressure testing procedure that may be performed by the therapy device of FIG. 1, according to an exemplary embodiment. [Figure 6B] FIG. 6B is a graph illustrating an active pressure testing procedure that may be performed by the therapy device of FIG. 1, according to an exemplary embodiment. [Figure 6C] FIG. 6C is a graph illustrating an uncontrolled pressure test procedure with variable leak rate that may be performed by the therapy device of FIG. 1, according to an exemplary embodiment. [Figure 6D] FIG. 6D is a graph illustrating an uncontrolled pressure test procedure at constant leak rate that may be performed by the therapy device of FIG. 1, according to an exemplary embodiment. [Figure 7A] FIG. 7A is a graph illustrating several pressure decay curves that may be generated and / or used by the therapy device of FIG. 1 to relate measured pressure to wound volume, according to an exemplary embodiment. [Figure 7B] FIG. 7B is a graph illustrating an unassisted pressure decay curve generated using the passive pressure test procedure of FIG. 6A and an assisted pressure decay curve generated using the active pressure test procedure of FIG. 6B in accordance with an exemplary embodiment. [Figure 8] FIG. 8 is a flowchart of a process for generating a pressure response model relating dynamic pressure response parameters to wound volume, according to an exemplary embodiment. [Figure 9]FIG. 9 is a flowchart of a process for estimating wound volume by applying a pressure stimulus to a negative pressure circuit and observing the dynamic pressure response, according to an exemplary embodiment. [Figure 10] FIG. 10 is a flowchart of a process for monitoring healing progress over time based on a set of wound volume estimates, according to an exemplary embodiment. [Figure 11] FIG. 11 is a graph illustrating wound volume and dripped fluid volume over time in accordance with an exemplary embodiment. [Figure 12] FIG. 12 is a flow chart of a process for determining an amount of drip fluid to deliver to a wound based on an estimated wound volume, according to an exemplary embodiment. [Figure 13] FIG. 13 is a graph illustrating a wound therapy process including a leak rate determination step, a wound volume determination step, and a fluid dripping step, according to an exemplary embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0061] Overview Referring generally to the figures, a wound therapy system with fluid dripping and removal and its components are shown according to various exemplary embodiments. The wound therapy system may include a therapy device and a wound dressing. The therapy device may include a dripping fluid canister, a removal fluid canister, a valve, a pneumatic pump, a drip pump, and a controller. The wound dressing may be applied to the patient's skin surrounding the wound. The therapy device may be configured to deliver a drip fluid to the wound to provide negative pressure wound therapy (NPWT) by maintaining the wound at a negative pressure. The components of the wound therapy device, the wound dressing, and / or the wound form a negative pressure circuit.

[0062] The controller may be configured to operate the air pressure pump, drip pump, valves, and / or other controllable components of the therapy device. In some embodiments, the controller performs a pressure test procedure by applying a pressure stimulus to the negative pressure circuit. For example, the controller may instruct the valve to close and operate the air pressure pump to establish negative pressure in the negative pressure circuit. Once negative pressure is established, the controller may deactivate the air pressure pump. The controller may open the valve for a predetermined time and then close it after the predetermined time has elapsed. In some embodiments, the controller operates the air pressure pump while the valve is closed to mitigate air leakage into the negative pressure circuit. The controller may monitor the dynamic pressure response of the negative pressure circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor. The dynamic pressure response may be characterized by various parameters including, for example, a purge depth parameter, a rebound parameter, a delta parameter, and a leak rate parameter (described in more detail below).

[0063] The controller can estimate the wound volume based on the observed dynamic pressure response. For example, the controller can apply the observed parameters as inputs to a pressure model that defines a relationship between the observed parameters and the volume of the negative pressure circuit and / or the volume of the wound. The model can include a polynomial approximation model, a neural network model, or any other model that relates the observed parameters to the volume of the negative pressure circuit and / or the volume of the wound. In some embodiments, the pressure model is a pre-existing model stored in the controller by the manufacturer of the therapy device. In other embodiments, the controller can generate the pressure model on-the-fly by performing a training procedure.

[0064] The training procedure may be the same as the pressure test procedure, except that the therapy device is connected to a training circuit having a known volume. For example, a wound dressing may be applied to a test device having a known volume, rather than to the patient's skin surrounding the wound. The controller may apply pressure stimuli to different training circuits having different known volumes, and observe the dynamic pressure response of each training circuit. Each of the known volumes may result in a different dynamic pressure response to the pressure stimuli. The controller may then associate the known volume of each training circuit with a corresponding dynamic pressure response. In some embodiments, the controller uses the dynamic pressure responses of the training circuits to generate a pressure model that defines the relationship between observed parameters of the dynamic pressure response (e.g., purge depth, rebound, delta, leak rate, etc.) and the volume of the training circuit. The pressure model may then be stored in the therapy device and used to estimate the volume of the wound, as described above.

[0065] In some embodiments, the controller is configured to perform a pressure test procedure, observe the dynamic pressure response, and estimate the wound volume multiple times during wound treatment. The controller can then determine the progress of healing based on the change in wound volume during wound treatment. In some embodiments, the controller is configured to determine a volume of drip fluid to be delivered to the wound based on the estimated wound volume. The volume of drip fluid to be delivered may be a predetermined percentage of the wound volume (e.g., 20%, 50%, 80%, etc.). The controller can then operate the drip pump to deliver the determined volume of drip fluid to the wound. These and other features of the wound therapy system are described in more detail below.

[0066] Wound Therapy Systems 1-4, a negative pressure wound therapy (NPWT) system 100 is shown according to an exemplary embodiment. The NPWT system 100 is shown to include a therapy device 102 fluidly connected to a wound dressing 112 via tubes 108 and 110. The wound dressing 112 may be adhered or sealed to the patient's skin 116 surrounding the wound 114. Some examples of wound dressings 112 that may be used in combination with the NPWT system 100 are described in detail in U.S. Patent No. 7,651,484, granted January 26, 2010, U.S. Patent No. 8,394,081, granted March 12, 2013, and U.S. Patent Application No. 14 / 087,418, filed November 22, 2013. The entire disclosures of each of these patents and patent applications are incorporated herein by reference.

[0067] The therapy device 102 can be configured to provide negative pressure wound therapy by reducing pressure at the wound 114. The therapy device 102 can draw a vacuum (relative to atmospheric pressure) at the wound 114 by removing wound exudate, air, and other fluids from the wound 114. Wound exudate can include fluids that exude from a patient's circulatory system to a lesion or site of inflammation. For example, wound exudate can include water and dissolved solutes such as blood, plasma proteins, white blood cells, platelets, and red blood cells. Other fluids removed from the wound 114 can include dripping fluid 105 that has already been delivered to the wound 114. The dripping fluid 105 can include, for example, a cleaning fluid, a prescription fluid, a medicinal fluid, an antibiotic fluid, or any other type of fluid that can be delivered to the wound 114 during wound treatment. The dripping fluid 105 can be held in a dripping fluid canister 104 and controllably dispensed to the wound 114 via a dripping fluid conduit 108. In some embodiments, the drip fluid canister 104 is removable from the therapy device 102 to allow the canister 106 to be refilled and replaced as needed.

[0068] Fluids 107 removed from the wound 114 pass through removal fluid conduit 110 and are collected in removal fluid canister 106. The removal fluid canister 106 may be a component of therapy device 102 configured to collect wound exudate and other fluids 107 removed from the wound 114. In some embodiments, the removal fluid canister 106 is removable from therapy device 102 to allow the canister 106 to be emptied and replaced as needed. A lower portion of the canister 106 may be filled with wound exudate and other fluids 107 removed from the wound 114, whereas an upper portion of the canister 106 may be filled with air. The therapy device 102 may be configured to draw a vacuum in the canister 106 by sucking air out of the canister 106. The reduced pressure within the canister 106 can be transferred via the tube 110 to the wound dressing 112 and the wound 114 such that the wound dressing 112 and the wound 114 are maintained at the same pressure as the canister 106 .

[0069] 2-4, a block diagram illustrating the therapy device 102 in greater detail is shown, according to an exemplary embodiment. The therapy device 102 is shown to include an air pressure pump 120, a drip pump 122, a valve 132, a filter 128, and a controller 118. The air pressure pump 120 can be fluidly coupled to the removal fluid canister 106 (e.g., via a conduit 136) and can be configured to draw a vacuum within the canister 106 by drawing air from the canister 106. In some embodiments, the air pressure pump 120 is configured to operate in both a forward and reverse direction. For example, the air pressure pump 120 can operate in a forward direction to draw air from the canister 106 to reduce the pressure within the canister 106. The air pressure pump 120 can operate in a reverse direction to pump air into the canister 106 to increase the pressure within the canister 106. The pneumatic pump 120 may be controlled by a controller 118, which is described in more detail below.

[0070] Similarly, the drip pump 122 may be fluidly coupled to the drip fluid canister 104 via tube 109 and to the wound dressing 112 via tube 108. The drip pump 122 may be operated to deliver the drip fluid 105 to the wound dressing 112 and the wound 114 by pumping the drip fluid 105 through tube 109 and tube 108, as shown in Figure 4. The drip pump 122 may be controlled by a controller 118, which will be described in more detail below.

[0071] The filter 128 can be positioned between the removal fluid canister 106 and the pneumatic pump 120 (e.g., along the conduit 136) such that air drawn from the canister 106 passes through the filter 128. The filter 128 can be configured to prevent liquid or solid particles from entering the conduit 136 and reaching the pneumatic pump 120. The filter 128 can include, for example, a bacterial filter that is hydrophobic and / or lipophilic such that aqueous and / or oily liquids bead up and adhere to the surface of the filter 128. The pneumatic pump 120 can be configured to provide sufficient airflow through the filter 128 so that the pressure drop across the filter 128 is not too large (e.g., so that the pressure drop does not substantially impede the application of negative pressure from the therapy device 102 to the wound 114).

[0072] In some embodiments, the therapy device 102 operates the valve 132 to controllably vent the negative pressure circuit, as shown in FIG. 3A. The valve 132 can be fluidly connected to the air pressure pump 120 and the filter 128 via a conduit 136. In some embodiments, the valve 132 is configured to control the flow of air between the conduit 136 and the environment surrounding the therapy device 102. For example, the valve 132 can be open to allow air flow into the conduit 136 via the vent 134 and the conduit 138, and closed to prevent air flow into the conduit 136 via the vent 134 and the conduit 138. The valve 132 can be opened and closed by the controller 118, which will be described in more detail below. When the valve 132 is closed, the air pressure pump 120 can draw a vacuum in the negative pressure circuit by causing air to flow through the filter 128 in a first direction, as shown in FIG. 2. The negative pressure circuit may include any components of the system 100 that can be maintained at a negative pressure when performing negative pressure wound therapy (e.g., conduit 136, removal fluid canister 106, tube 110, wound dressing 112, and / or wound 114). For example, the negative pressure circuit may include conduit 136, removal fluid canister 106, tube 110, wound dressing 112, and / or wound 114. When valve 132 is open, airflow from the environment surrounding therapy device 102 may enter conduit 136 via vent 134 and conduit 138 and fill voids in the negative pressure circuit. Airflow from conduit 136 into canister 106 and other volumes in the negative pressure circuit may pass through filter 128 in a second direction opposite to the first direction, as shown in FIG. 3A.

[0073] In some embodiments, the therapy device 102 vents the negative pressure circuit through an orifice 158, as shown in FIG. 3B. The orifice 158 may be a small opening in the conduit 136 or any other component of the negative pressure circuit (e.g., removal fluid canister 106, tube 110, tube 111, wound dressing 112, etc.) and may allow air to leak into the negative pressure circuit at a known rate. In some embodiments, the therapy device 102 vents the negative pressure circuit through an orifice 158 rather than operating a valve 132. The valve 132 may be omitted from the therapy device 102 in any embodiment that includes an orifice 158. The rate at which air leaks into the negative pressure circuit through the orifice 158 may be substantially constant or may vary as a function of negative pressure, depending on the shape of the orifice 158. For embodiments in which the leak rate from the orifice 158 is variable, the controller 118 can use a stored relationship between negative pressure and leak rate to calculate the leak rate from the orifice 158 based on the measured negative pressure. Whether the leak rate from the orifice 158 is substantially constant or variable, the leakage of air through the orifice 158 into the negative pressure circuit can be used to generate a pressure decay curve for use in estimating the volume of the wound 114, as described with reference to Figures 5-9.

[0074] In some embodiments, the therapy device 102 includes various sensors. For example, the therapy device 102 is shown to include a pressure sensor 130 configured to measure the pressure in the canister 106 and / or the pressure at the wound dressing 112 or wound 114. In some embodiments, the therapy device 102 includes a pressure sensor 113 configured to measure the pressure in the tube 111. The tube 111 may be connected to the wound dressing 112 and may be used only to measure the pressure at the wound dressing 112 or wound 114 without a secondary function such as directing dripping fluid 105 or wound exudate. In various embodiments, the tubes 108, 110, and 111 may be physically separate tubes or separate lumens within a single tube connecting the therapy device 102 to the wound dressing 112. Thus, tube 110 may be described as a negative pressure lumen that functions to apply negative pressure to wound dressing 112 or wound 114, whereas tube 111 may be described as a sensing lumen configured to sense pressure at wound dressing 112 or wound 114. Pressure sensors 130 and 113, in various embodiments, may be located within therapy device 102, positioned anywhere along tubes 108, 110 and 111, or located in wound dressing 112. Pressure measurements recorded by pressure sensors 130 and / or 113 may be passed to controller 118, which uses the pressure measurements as inputs to various pressure testing and control operations performed by controller 118 (described in more detail with reference to FIGS. 5-12).

[0075] The controller 118 may be configured to operate the air pressure pump 120, the drip pump 122, the valve 132, and / or other controllable components of the therapy device 102. In some embodiments, the controller 118 performs a pressure test procedure by applying a pressure stimulus to the negative pressure circuit. For example, the controller 118 may operate the air pressure pump 120 to instruct the valve 132 to close and establish a negative pressure in the negative pressure circuit. Once the negative pressure is established, the controller 118 may deactivate the air pressure pump 120. The controller 118 may open the valve 132 for a predetermined time and then close it after the predetermined time has elapsed. The controller 118 may monitor the dynamic pressure response of the negative pressure circuit to the pressure stimulus using pressure measurements recorded by the pressure sensors 130 and / or 113. The dynamic pressure response may be characterized by various parameters including, for example, a purge depth parameter, a rebound parameter, a delta parameter, and a leak rate parameter (described in more detail with reference to FIG. 5).

[0076] The controller 118 can estimate the volume of the wound 114 based on the observed dynamic pressure response. For example, the controller 118 can apply the observed parameters as inputs to a pressure model that defines a relationship between the observed parameters and the volume of the negative pressure circuit and / or the volume of the wound 114. The model can include a polynomial approximation model, a neural network model, or any other model that relates the observed parameters to the volume of the negative pressure circuit and / or the volume of the wound 114. In some embodiments, the pressure model is a pre-existing model stored in the controller 118 by the manufacturer of the therapy device 102. In other embodiments, the controller 118 can generate a pressure model on-the-fly by performing a training procedure.

[0077] The training procedure may be the same as the pressure test procedure, except that the therapy device 102 is connected to a training circuit having a known volume. For example, the wound dressing 112 may be applied to a test device having a known volume, rather than to the patient's skin 116 surrounding the wound 114. The controller 118 may apply pressure stimuli to different training circuits having different known volumes, and observe the dynamic pressure response of each training circuit. Each of the known volumes may result in a different dynamic pressure response to the pressure stimuli. The controller 118 may then associate the known volume of each training circuit with a corresponding dynamic pressure response. In some embodiments, the controller 118 uses the dynamic pressure responses of the training circuits to generate a pressure model that defines the relationship between observed parameters of the dynamic pressure response (e.g., purge depth, rebound, delta, leak rate, etc.) and the volume of the training circuit. The pressure model may then be stored in the controller 118 and used to estimate the volume of the wound 114, as previously described.

[0078] In some embodiments, the controller 118 is configured to perform a pressure test procedure, observe the dynamic pressure response, and estimate the wound volume multiple times during wound treatment. The controller 118 can then determine the progress of healing based on the change in wound volume during wound treatment. In some embodiments, the controller 118 is configured to determine a volume of dripping fluid 105 to be delivered to the wound 114 based on the estimated wound volume. The volume of dripping fluid 105 to be delivered may be a predetermined percentage (e.g., 20%, 50%, 80%, etc.) of the volume of the wound 114. The controller 118 can then operate the drip pump 122 to deliver the determined volume of dripping fluid 105 to the wound 114. These and other features of the controller 118 are described in more detail with reference to FIGS. 5-12.

[0079] In some embodiments, the therapy device 102 includes a user interface 126. The user interface 126 may include one or more buttons, dials, sliders, keys, or other input devices configured to receive input from a user. The user interface 126 may also include one or more displays (e.g., LEDs, LCD displays, etc.), speakers, tactile feedback devices, or other output devices configured to provide information to a user. In some embodiments, pressure measurements recorded by the pressure sensors 130 and / or 113 are presented to the user via the user interface 126. The user interface 126 may also display warnings generated by the controller 118. For example, the controller 118 may generate a "no canister" warning if the canister 106 is not detected.

[0080] In some embodiments, the therapy device 102 includes a data communication interface 124 (e.g., a USB port, a wireless transceiver, etc.) configured to transmit and receive data. The communication interface 124 may include a wired or wireless communication interface (e.g., a jack, an antenna, a transmitter, a receiver, a transceiver, a wire terminal, etc.) for data communication with an external system or device. In various embodiments, the communication may be direct communication (e.g., local wired or wireless communication) or communication over 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 port for transmitting and receiving data over an Ethernet-based communication link or network. In another example, the communication interface 124 may include a Wi-Fi transceiver for communication over a wireless communication network or a cellular or mobile phone communication transceiver.

[0081] Control device 5, a block diagram illustrating the controller 118 in more detail is shown, according to an exemplary embodiment. The controller 118 is shown to include processing circuitry 140, including a processor 142 and a memory 144. The processor 142 may be a general-purpose or special-purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable processing components. The processor 142 is configured to execute computer code or instructions stored in the memory 144 or received from other computer readable media (e.g., CD-ROM, network storage, remote server, etc.).

[0082] The memory 144 may include one or more devices (e.g., memory units, memory devices, storage devices, etc.) for storing data and / or computer code for completing and / or facilitating various processes described in this disclosure. The memory 144 may include random access memory (RAM), read only memory (ROM), hard drive storage, temporary storage, non-volatile memory, flash memory, optical memory, or any other suitable memory for storing software objects and / or computer instructions. The memory 144 may include database components, object code components, script components, or any other type of information structure for supporting various activities and information structures described in this disclosure. The memory 144 may be communicatively connected to the processor 142 via the processing circuitry 140, and may include computer code for executing (e.g., by the processor 142) one or more processes described herein. When the processor 142 executes instructions stored in the memory 144, the processor 142 generally configures the controller 118 (more specifically, the processing circuitry 140) to complete such activities.

[0083] The controller 118 is shown to include a pump controller 146 and a valve controller 150. The pump controller 146 may be configured to operate the pumps 120-122 by generating and providing control signals to the pumps 120-122. The control signals provided to the pumps 120-122 may cause the pumps 120-122 to activate, deactivate, or achieve variable capacity or speed (e.g., operate at half speed, operate at full speed, etc.). Similarly, the valve controller 150 may be configured to operate the valve 132 by generating and providing control signals to the valve 132. The control signals provided to the valve 132 may cause the valve 132 to open, close, or achieve a specified intermediate position (e.g., 1 / 3 open, 1 / 2 open, etc.). In some embodiments, the pump controller 146 and the valve controller 150 are used by other components of the controller 118 (e.g., the test procedure controller 148, the wound volume estimator 156, etc.) to operate the pumps 120-122 and the valves 132 when performing the processes described herein.

[0084] In some embodiments, the pump controller 146 uses input from a canister sensor configured to detect whether the removal fluid canister 106 is present. The pump controller 146 can be configured to activate the active pneumatic pump 120 only when the removal fluid canister 106 is present. For example, the pump controller 146 can check whether the canister 106 is present and can activate the pneumatic pump 120 in response to determining that the canister 106 is present. However, if the canister 106 is not present, the pump controller 146 may prevent the pneumatic pump 120 from operating. Similarly, the pump controller 146 can be configured to activate the active drip pump 122 only when the drip fluid canister 104 is present. For example, the pump controller 146 can check whether the canister 104 is present and can activate the active drip pump 122 in response to determining that the canister 104 is present. However, if the canister 104 is not present, the pump controller 146 may prevent the drip pump 122 from operating.

[0085] The controller 118 is shown to include a pressure monitor 152. The pressure monitor 152 may be configured to monitor the pressure in the removal fluid canister 106 and / or the pressure in the wound dressing 112 or wound 114 using feedback from the pressure sensors 130 and / or 113. For example, the pressure sensors 130 and / or 113 may provide pressure measurements to the pressure monitor 152. The pressure monitor 152 may use the pressure measurements to determine the pressure in the canister 106 and / or the pressure in the wound dressing 112 or wound 114 in real time. The pressure monitor 152 may provide pressure values ​​to the model generator 154, the pump controller 146, the test procedure controller 148, and / or the valve controller 150 to be used as inputs to control processes performed by such components.

[0086] 5 and 6A-6C, the controller 118 is shown to include a test procedure controller 148. The test procedure controller 148 can be configured to execute a pressure test procedure to induce and observe a dynamic pressure response. When the therapy device 102 is connected to a wound dressing 112 applied to the patient's skin 116 over the wound 114, the test procedure controller 148 can observe the dynamic pressure response of the negative pressure circuit (which may have an unknown volume) including the conduit 136, the removal fluid canister 106, the tube 110, the wound dressing 112, and / or the wound 114. When the therapy device 102 is connected to a wound dressing 112 applied to a training device having a known volume, the test procedure controller 148 can observe the dynamic pressure response of the training circuit including the conduit 136, the removal fluid canister 106, the tube 110, the wound dressing 112, and / or the training device.

[0087] 6A, a graph 200 is shown illustrating a passive pressure test procedure performed by the test procedure controller 148, according to an exemplary embodiment. The test procedure controller 148 can be configured to operate the air pressure pump 120 to establish a negative pressure in the negative pressure circuit and / or training circuit. Negative pressure may be defined as the difference between the atmospheric pressure surrounding the therapy device 102 and the pressure in the negative pressure circuit and / or training circuit (i.e., the amount by which the atmospheric pressure exceeds the pressure in the negative pressure circuit and / or training circuit). For example, at time t0, the negative pressure is shown to have a value of P0 (e.g., 0 mmHg), which represents the pressure in the negative pressure circuit and / or training circuit being equal to the atmospheric pressure surrounding the therapy device 102.

[0088] At time t0, the test procedure controller 148 starts operating the air pressure pump 120 to reduce the negative pressure in the negative pressure circuit and / or training circuit. The negative pressure continues to reduce until it reaches a negative pressure value of P8 mmHg (e.g., 125 mmHg) below atmospheric pressure at time t1. Between time t1 and time t2, the test procedure controller 148 maintains the negative pressure at the value of P8 by operating the air pressure pump 120 as necessary to remove air from the negative pressure circuit and / or training circuit. The test procedure controller 148 may then apply a pressure stimulus to the negative pressure circuit and / or training circuit after negative pressure has been established in the negative pressure circuit and / or training circuit.

[0089] At time t2, the test procedure controller 148 deactivates the air pressure pump 120. Beginning at time t2, the magnitude of the negative pressure in the negative pressure circuit and / or training circuit may decrease due to air leaking into the negative pressure circuit and / or training circuit while the valve 132 is closed. The rate at which the negative pressure decreases while the valve 132 is closed is determined by the slope of the line 202 from time t2 to time t3. The test procedure controller 148 may determine the slope of the line 202 from time t2 to time t3 and may store this slope as the value of a leak rate parameter. The leak rate parameter may be one of the parameters that characterize the dynamic pressure response of the negative pressure circuit and / or training circuit.

[0090] At time t3, the test procedure controller 148 applies a pressure stimulus to the negative pressure circuit and / or the training circuit. Applying the pressure stimulus may include operating the valve 132 to controllably vent the negative pressure circuit and / or the training circuit. For example, the test procedure controller 148 may open the valve 132 at time t3 to allow air flow into the negative pressure circuit and / or the training circuit. The test procedure controller 148 may hold the valve 132 open for a predetermined time (i.e., from time t3 to time t4) and may close the valve 132 after the predetermined time has elapsed (i.e., at time t4).

[0091] At time t4, the test procedure controller 148 may observe the dynamic pressure response of the negative pressure circuit and / or the training circuit to the pressure stimulus. The dynamic pressure response may be characterized by several additional parameters including a purge depth parameter, a rebound parameter, and a delta parameter. The purge depth parameter may be defined as the difference between the measurement of the negative pressure P7 before the valve 132 is opened and the measurement of the negative pressure P3 while the valve 132 is open (i.e., purge depth=P7-P3). The rebound parameter may be defined as the difference between the measurement of the negative pressure P6 after the valve 132 is closed and the measurement of the negative pressure P3 while the valve 132 is open (i.e., rebound=P6-P3). The delta parameter may be defined as the difference between the measurement of the negative pressure P7 before the valve 132 is opened and the measurement of the negative pressure P6 after the valve 132 is closed (i.e., delta=P7-P6).

[0092] In some embodiments, the test procedure controller 148 applies the pressure stimulus one or more more times until the negative pressure reaches the threshold P1 when the valve 132 is closed. Between each application of the pressure stimulus, the test procedure controller 148 may wait another predetermined time (i.e., from time t4 to time t5 and from time t6 to time t7). For example, the test procedure controller 148 may wait a predetermined time from time t4 to time t5 and apply the pressure stimulus again at time t5. The test procedure controller 148 may open the valve 132 at time t5 to allow air flow into the negative pressure circuit and / or the training circuit. The test procedure controller 148 may keep the valve 132 open for a predetermined time (i.e., from time t5 to time t6) and close the valve 132 after the predetermined time has elapsed (i.e., at time t6). At time t6, the test procedure controller 148 may store values ​​of the purge depth parameter (i.e., purge depth=P5-P1), the rebound parameter (i.e., rebound=P4-P1), and the delta parameter (i.e., delta=P5-P4) in response to the second application of the pressure stimulus. This process may be repeated until the value of the negative pressure in the negative pressure circuit and / or training circuit reaches the threshold pressure value P1 at time t9.

[0093] 6B, a graph 210 is shown illustrating an active test procedure performed by the test procedure controller 148, according to an exemplary embodiment. The test procedure controller 148 can be configured to operate the air pressure pump 120 to establish a negative pressure in the negative pressure circuit and / or training circuit. Negative pressure may be defined as the difference between the atmospheric pressure surrounding the therapy device 102 and the pressure in the negative pressure circuit and / or training circuit (i.e., the amount by which the atmospheric pressure exceeds the pressure in the negative pressure circuit and / or training circuit). For example, at time t0, the negative pressure is shown to have a value of P0 (e.g., 0 mmHg), which represents the pressure in the negative pressure circuit and / or training circuit being equal to the atmospheric pressure surrounding the therapy device 102.

[0094] The active test procedure illustrated in FIG. 6B may be substantially similar to the passive test procedure illustrated in FIG. 6A. However, in the active test procedure, the controller 148 may be configured to operate the air pressure pump 120 by brief controlled actuation of the air pressure pump 120 while the valve 132 is closed (e.g., between times t4 and t5, between times t6 and t7, and between times t8 and t9) to compensate for high air leakage rates into the negative pressure circuit and / or training circuit. In the graph 210, a line 212 represents the pressure in the negative pressure circuit and / or training circuit as a function of time. The actual leakage rate of air into the negative pressure circuit and / or training circuit while the valve 132 is closed is represented by the slope of line segment 216, whereas the slope of line 214 represents the average or assisted leakage rate between times t4 and t5. The average or assisted leakage rate is A portion of the air is removed from the negative pressure circuit and / or training circuit by brief controlled actuation of the air pressure pump 120 between times t4 and t5 (each controlled actuation increasing the negative pressure) so that the negative pressure equals TIFF0007654726000001.tif17170. Similar negative pressure adjustments can be made between times t6 and t7 and between times t8 and t9. In this manner, the inflow of air into the negative pressure circuit and / or training circuit can be mitigated to compensate for the actual high leak rate while the valve 132 is closed.

[0095] 6C-6D, graphs 220 and 230 are shown illustrating an uncontrolled test procedure implemented by the test procedure controller 148, according to an exemplary embodiment. Unlike the passive and active test procedures described with reference to FIGS. 6A and 6B, an uncontrolled test procedure may be implemented for embodiments that do not utilize valve 132 and in which therapy device 102 includes orifice 158 instead of valve 132. Graph 220 illustrates an uncontrolled test procedure when orifice 158 leaks air into the negative pressure circuit and / or training circuit at a variable leak rate, whereas graph 220 illustrates an uncontrolled test procedure when orifice 158 leaks air into the negative pressure circuit and / or training circuit at a substantially constant leak rate.

[0096] In both uncontrolled test procedures, at time t0, the test procedure controller 148 starts operation of the air pressure pump 120 to reduce the pressure in the negative pressure circuit and / or the training circuit. The negative pressure continues to reduce until it reaches a negative pressure value of P2 mmHg (e.g., 125 mmHg) below atmospheric pressure at time t1.

[0097] At time t1, the test procedure controller 148 deactivates the air pressure pump 120. Beginning at time t1, the magnitude of the negative pressure in the negative pressure circuit and / or training circuit may decrease due to air leaking into the negative pressure circuit and / or training circuit through the orifice 158. The rate at which the negative pressure decreases is determined by the slope of line 222 between time t1 and time t2. In graph 220, the leakage of air into the negative pressure circuit and / or training circuit through the orifice 158 occurs more quickly near time t1 and more slowly near time t2, as shown by the slope of line 222 approaching zero as time passes between t1 and t2. In graph 230, the leakage of air into the negative pressure circuit and / or training circuit through the orifice 158 occurs at a substantially constant rate, as shown by the generally straight line 232. In either scenario, the test procedure controller 148 may determine the slope of the line 222 between time t1 and time t2 one or more times and store this slope as the value of the leak rate parameter. Alternatively, the leak rate parameter may be defined as the time required for the negative pressure to drop from P2 to P1 and may be calculated by subtracting t1 from t2 (i.e., t2-t1). The leak rate parameter may be one of the parameters that characterize the dynamic pressure response of the negative pressure circuit and / or the training circuit.

[0098] The test procedure controller 148 can be configured to perform passive, active, and / or uncontrolled test procedures in various embodiments. Passive test procedures may be preferred under most conditions and may be the primary or default test procedures used by the test procedure controller 148. However, active test procedures may be preferred when leak rates are high and may be used by the test procedure controller 148 in response to a determination that the actual leak rate exceeds a predetermined leak rate threshold. Uncontrolled test procedures may be preferred for embodiments in which the valve 132 is replaced by an orifice 158.

[0099] The leak rate can be determined in a variety of ways. In some embodiments, the leak rate is determined by operating the pneumatic pump 120 to achieve a predetermined negative pressure in the negative pressure circuit and measuring the pressure decay over time. In some embodiments, the leak rate is determined based on the efficiency of the pneumatic pump 120 or the power consumed by the pneumatic pump 120. For example, the pump controller 146 can be configured to perform brief controlled actuations of the pneumatic pump 120 to maintain the negative pressure at a setpoint or to prevent the negative pressure from decreasing at a rate above a predetermined leak rate threshold, as previously described. The number or frequency of these brief controlled actuations of the pneumatic pump 120 depends on the leak rate and can be used to determine the leak rate. Similarly, the power consumed by the pneumatic pump 120 to perform these brief controlled actuations depends on the leak rate and can be used to determine the leak rate. For example, the controller 118 may be configured to record the number of short controlled actuations of the pneumatic pump 120 within a given period of time, measure the frequency or interval of short controlled actuations, measure the duty cycle of the pneumatic pump 120 (e.g., the percentage of time that the pneumatic pump 120 is operating), or measure the amount of power consumed by the pneumatic pump 120 to perform the short controlled actuations. Any of these metrics may characterize the pump efficiency and can be stored as a pump efficiency parameter. The controller 118 can use a stored formula or predetermined relationship to calculate the leakage rate as a function of the pump efficiency.

[0100] Referring again to FIG. 5, the controller 118 is shown to include a model generator 154. The model generator 154 can be configured to generate a model that defines a relationship between parameters of the dynamic pressure response and the volume of the wound 114. To generate the model, the model generator 154 can cause the test procedure controller 148 to execute the pressure test procedure outlined above for a number of different training circuits having a number of different known volumes (e.g., 50cc, 100cc, 200cc, 300cc, etc.). When the pressure test procedure is performed on a training circuit having a known volume, the pressure test procedure may be referred to as a training procedure. Each execution of the training procedure may include applying a pressure stimulus to a training circuit having a known volume, observing the dynamic pressure response of the training circuit to the pressure stimulus, and correlating the known volume with the dynamic pressure response of the training circuit.

[0101] In some embodiments, the model generator 154 records values ​​of parameters of the dynamic pressure response (i.e., leak rate, purge depth, rebound, delta, etc.) for each known volume and associates those values ​​with the known volumes. The parameter values ​​and known volumes form a set of training data that can be used to build a model. The parameter values ​​form a set of model input training data, whereas the known volumes form a set of model output training data. The model generator 154 can use any of a variety of model generation techniques to build a model (i.e., a mathematical model) that associates parameter values ​​with corresponding volumes as a set of training data.

[0102] In some embodiments, the model generator 154 creates a polynomial approximation model to relate the values ​​of the parameters to the corresponding volumes. To generate the polynomial approximation model, the model generator 154 can perform a curve fitting process, such as polynomial regression, using any of a variety of regression techniques. Examples of regression techniques that can be used by the model generator 154 include least squares, ordinary least squares, linear least squares, partial least squares, total least squares, generalized least squares, weighted least squares, nonlinear least squares, nonnegative least squares, iteratively reweighted least squares, ridge regression, least absolute deviation, Bayesian linear regression, Bayesian multivariate linear regression, and the like.

[0103] In other embodiments, the model generator 154 creates a neural network model to associate values ​​of parameters with corresponding volumes. To generate the neural network model, the model generator 154 can perform a machine learning process. Examples of machine learning techniques that can be used by the model generator 154 include decision tree learning, association rule learning, artificial neural networks, deep learning, inductive logic programming, support vector machines, clustering, Bayesian networks, reinforcement learning, representation learning, similarity and metric learning, sparse dictionary learning, genetic algorithms, rule-based machine learning, and the like.

[0104] 7A, a graph 250 is shown illustrating several pressure decay curves 252, 254, 256, and 258, according to an exemplary embodiment. Each of the pressure decay curves 252-258 corresponds to a known volume and represents the pressure in the negative pressure circuit and / or training circuit as a function of time for the corresponding volume. For example, the pressure decay curve 252 corresponds to a volume of 300 cc, the pressure decay curve 254 corresponds to a volume of 200 cc, the pressure decay curve 256 corresponds to a volume of 100 cc, and the pressure decay curve 258 corresponds to a volume of 50 cc. Each of the pressure decay curves 252-258 may be created by the model generator 154 using any of the modeling techniques described above. For example, the pressure decay curves 252-258 may be created by performing a pressure test procedure for each known volume and plotting the pressure decay over time for each known volume.

[0105] In some embodiments, the controller 118 uses the pressure decay curves 252-258 when estimating the volume of the wound 114 to convert the measured pressure values ​​to corresponding volumes. For example, the controller 118 can measure the pressure of the negative pressure circuit and identify the time at which the pressure was measured. The controller 118 can interpolate between the pressure decay curves 252-258 to determine an interpolated pressure value that corresponds to the measured pressure and time pair. For example, at time t1, the controller 118 may observe a pressure value of P1. The combination of time t1 and pressure P1 defines a point 260 in the graph 250. The point 260 is approximately halfway between the pressure decay curve 252 and the pressure decay curve 254. The controller 118 can interpolate between the pressure decay curves 252 and 254 to estimate that the volume of the negative pressure circuit is approximately halfway between the known volume corresponding to the pressure decay curve 252 and the known volume corresponding to the pressure decay curve 254 (approximately 250 cc). In other embodiments, the controller 118 estimates the volume of the wound 114 by applying the observed parameters of the dynamic pressure response as inputs to a pressure model.

[0106] 7B, a graph 260 is shown illustrating an unassisted pressure decay curve 264 and an assisted pressure decay curve 262, according to an exemplary embodiment. In the graph 260, both the unassisted pressure decay curve 264 and the assisted pressure decay curve 262 correspond to the same volume of the negative pressure circuit and / or training circuit. The unassisted pressure decay curve 264 illustrates the pressure decay during the passive test procedure shown in FIG. 6A (i.e., when the air pump 120 is not operated to compensate for the high leak rate). Conversely, the assisted pressure decay curve 262 illustrates the pressure decay during the active test procedure (i.e., when the air pump 120 is operated to compensate for the high leak rate). As described with reference to FIG. 6B, by operating the air pump 120 during the active test procedure, the pressure decay is mitigated, thus resulting in a more gentle pressure decay curve 262 with assistance relative to the unassisted pressure decay curve 264.

[0107] Referring again to FIG. 5, the controller 118 is shown to include a wound volume estimator 156. The wound volume estimator 156 can be configured to estimate the volume of the wound 114 based on pressure measurements collected by the pressure sensors 130 and / or 113. In some embodiments, the wound volume estimator 156 estimates the volume of the wound 114 by performing a pressure test procedure. The pressure test procedure can include applying a pressure stimulus to the negative pressure circuit and observing a dynamic pressure response of the negative pressure circuit to the pressure stimulus. As described above, the negative pressure circuit can include any components of the system 100 that can be maintained at a negative pressure when performing negative pressure wound therapy (e.g., the conduit 136, the removal fluid canister 106, the tube 110, the wound dressing 112, and / or the wound 114).

[0108] To perform the pressure test procedure, the wound volume estimator 156 may command the valve 132 to close and operate the air pressure pump 120 to establish a negative pressure in the negative pressure circuit. Once the negative pressure is established, the wound volume estimator 156 may deactivate the air pressure pump 120. The wound volume estimator 156 may cause the valve 132 to open for a predetermined period of time and then close after the predetermined period of time has elapsed. The wound volume estimator 156 may monitor the dynamic pressure response of the negative pressure circuit to the pressure stimulus using pressure measurements recorded by the pressure sensors 130 and / or 113. The dynamic pressure response may be characterized by various parameters including, for example, a purge depth parameter, a rebound parameter, a delta parameter, and a leak rate parameter, as previously described.

[0109] The wound volume estimator 156 can estimate the volume of the wound 114 based on the observed dynamic pressure response. For example, the wound volume estimator 156 can apply the observed parameters as inputs to a pressure model that defines a relationship between the observed parameters and the volume of the negative pressure circuit and / or the volume of the wound 114. In some embodiments, the pressure model is a model created by the model generator 154 (e.g., by performing a training procedure based on training data collected using a training circuit). The model may include a polynomial approximation model, a neural network model, or any other model that relates the observed parameters to the volume of the negative pressure circuit and / or the volume of the wound 114. In other embodiments, the pressure model is a pre-existing model stored in the memory 144 by the manufacturer of the therapy device 102.

[0110] In some embodiments, the wound volume estimator 156 is configured to perform a pressure test procedure, observe the dynamic pressure response, and estimate the wound volume multiple times during wound treatment. The wound volume estimator 156 can then determine the progress of healing based on the change in wound volume during wound treatment. In some embodiments, the wound volume estimator 156 is configured to determine a volume of dripping fluid 105 to be delivered to the wound 114 based on the estimated wound volume. The volume of dripping fluid 105 to be delivered may be a predetermined percentage (e.g., 20%, 50%, 80%, etc.) of the volume of the wound 114. The wound volume estimator 156 can then operate the drip pump 122 to deliver the determined volume of dripping fluid 105 to the wound 114.

[0111] Flow Diagram 8, a flow chart of a process 300 for generating a pressure model is shown, according to an exemplary embodiment. The process 300 may be performed by one or more components of the therapy device 102 to create a model that characterizes the dynamic pressure response of the training circuit and / or the negative pressure circuit. For example, the process 300 may be performed by the controller 118, the air pressure pump 120, the valve 132, and / or the pressure sensors 130 and / or 113. In some embodiments, the process 300 is performed by the test procedure controller 148 and the model generator 154.

[0112] The process 300 is shown to include applying a pressure stimulus to a training circuit having a known volume (step 302). The training circuit may include one or more components of the therapy device 102 (e.g., conduit 136, removal fluid canister 106, etc.) and / or other components of the system 100 (e.g., tube 110, wound dressing 112). Under wound treatment conditions, the wound dressing 112 is typically applied to the patient's skin 116 surrounding the wound 114. However, the training circuit may replace the wound 114 with a training device having a known volume. Step 302 may include instructing the valve 132 to close and operating the air pressure pump 120 to establish a negative pressure in the training circuit. Once the negative pressure is established, the air pressure pump 120 may be deactivated. Step 302 may include opening the valve 132 for a predetermined time and then closing the valve 132 after the predetermined time has elapsed.

[0113] Process 300 is shown to include observing a dynamic pressure response of the training circuit to a pressure stimulus (step 304) and correlating a known volume of the training circuit with the dynamic pressure response (step 306). Step 304 may include monitoring the pressure of the training circuit over time using pressure measurements recorded by pressure sensors 130 and / or 113. The dynamic pressure response may be characterized by various parameters including, for example, a purge depth parameter, a rebound parameter, a delta parameter, and a leak rate parameter, as previously described. Step 306 may include storing values ​​of the parameters of the dynamic pressure response as input training data and storing the known volume of the training circuit as output training data corresponding to the input training data.

[0114] Process 300 is shown to include determining whether all volumes have been tested (step 308). If not all volumes have been tested (i.e., step 308 results in "no"), the training device to which therapy device 102 is connected can be replaced with a different training device having a different known volume. Steps 302-306 can then be repeated applying pressure stimuli to observe the dynamic pressure response of the training circuit for each known volume. Each set of dynamic pressure response parameters can be stored as input training data, and each set and the corresponding known volume can be stored as output training data.

[0115] Once all volumes have been tested (i.e., the result of step 308 is "yes"), process 300 may proceed to generating a pressure model (step 310). Step 310 may include building a model (i.e., a mathematical model) that relates values ​​of dynamic pressure response parameters to corresponding volumes as a set of training data using any of a variety of model generation techniques.

[0116] In some embodiments, the model generated in step 310 is a polynomial approximation model. Step 310 may include performing a curve fitting process, such as polynomial regression, using any of a variety of regression techniques. Examples of regression techniques that can be used in step 310 include least squares, ordinary least squares, linear least squares, partial least squares, total least squares, generalized least squares, weighted least squares, nonlinear least squares, nonnegative least squares, iteratively reweighted least squares, ridge regression, least absolute deviation, Bayesian linear regression, Bayesian multivariate linear regression, and the like.

[0117] In some embodiments, the model generated in step 310 is a neural network model. Step 310 may include generating a neural network model that relates values ​​of dynamic pressure response parameters to corresponding volumes as a set of training data using any of a variety of machine learning techniques. Examples of machine learning techniques that may be used in step 310 include decision tree learning, association rule learning, artificial neural networks, deep learning, inductive logic programming, support vector machines, clustering, Bayesian networks, reinforcement learning, representation learning, similarity and metric learning, sparse dictionary learning, genetic algorithms, rule-based machine learning, and the like. The pressure model may then be stored for use in estimating the volume of the wound 114.

[0118] 9, a flow chart of a process 400 for estimating wound volume is shown, according to an exemplary embodiment. The process 400 may be performed by one or more components of the therapy device 102 to estimate the volume of the wound 114. For example, the process 400 may be performed by the controller 118, the air pressure pump 120, the valve 132, and / or the pressure sensors 130 and / or 113. In some embodiments, the process 400 is performed by the test procedure controller 148 and the wound volume estimator 156.

[0119] The process 400 is shown to include applying a pressure stimulus to a negative pressure circuit having an unknown volume (step 402). The negative pressure circuit may include one or more components of the therapy device 102 (e.g., conduit 136, removal fluid canister 106, etc.) and / or other components of the system 100 (e.g., tube 110, wound dressing 112, wound 114). Under wound treatment conditions, the wound dressing 112 may be applied to the patient's skin 116 surrounding the wound 114. Thus, the volume of the wound 114 forms part of the negative pressure circuit. Step 402 may include commanding the valve 132 to close and operating the air pressure pump 120 to establish a negative pressure in the negative pressure circuit. Once the negative pressure is established, the air pressure pump 120 may be deactivated. Step 402 may include opening the valve 132 for a predetermined time and then closing the valve 132 after the predetermined time has elapsed. In some embodiments, step 402 includes performing passive and / or active test procedures, as described with reference to Figures 6A-6B.

[0120] Process 400 is shown to include observing a dynamic pressure response of the negative pressure circuit to a pressure stimulus (step 404) and determining values ​​for parameters characterizing the dynamic pressure response (step 406). Step 404 may include monitoring the pressure of the negative pressure circuit over time using pressure measurements recorded by pressure sensors 130 and / or 113. The dynamic pressure response may be characterized by a variety of parameters including, for example, a purge depth parameter, a rebound parameter, a delta parameter, and a leak rate parameter, as previously described. Step 406 may include storing values ​​of the parameters of the dynamic pressure response.

[0121] Process 400 is shown to include applying the values ​​of the parameters as inputs to a pressure response model (step 408) that defines wound volume as a function of the parameters. In some embodiments, the pressure response model is a model created by performing process 300 (e.g., by performing a regression or machine learning process using training data collected using a training circuit). The model may include a polynomial approximation model, a neural network model, or any other model that relates the observed parameters to the volume of the negative pressure circuit and / or the volume of the wound 114.

[0122] Process 400 is shown to include estimating a wound volume based on the output of the model (step 410). In some embodiments, the output of the pressure response model is an estimated volume of the wound 114. Thus, the output of the pressure response model may be used as the estimated wound volume. In other embodiments, the output of the pressure response model is an estimated volume of the negative pressure circuit. If the output of the pressure response model is an estimated volume of the negative pressure circuit, step 410 may include subtracting known volumes of other components of the negative pressure circuit to determine the estimated volume of the wound 114. For example, step 410 may include subtracting known volumes of the conduit 136, removal fluid canister 106, tube 110, and / or wound dressing 112 such that the only volume remaining is the volume of the wound 114.

[0123] In some embodiments, the volume of the removal fluid canister 106 forming part of the negative pressure circuit is limited to the volume of air in the canister 106. The volume of air in the canister 106 may vary based on the level of the removal fluid 107 in the canister 106. In some embodiments, the removal fluid canister 106 includes a sensor (e.g., a level sensor, a weight sensor, etc.) that operates to record the level of the removal fluid 107 in the canister 106. The observed level of the removal fluid 107 can then be used to estimate the volume of air in the canister 106. In other embodiments, the volume of air in the canister 106 can be estimated by performing a dead space detection process. An example of a dead space detection process that can be used to estimate the volume of air in the canister 106 is described in detail in U.S. Provisional Patent Application No. 62 / 577,579, filed October 26, 2017, the entire disclosure of which is incorporated herein by reference.

[0124] 10, a flow chart of a process 500 for monitoring healing progress over time is shown, according to an exemplary embodiment. The process 500 may be performed by one or more components of the therapy device 102 to assess healing progress based on the volume of the wound 114. For example, the process 500 may be performed by the controller 118, the air pressure pump 120, the valve 132, and / or the pressure sensors 130 and / or 113.

[0125] The process 500 is shown to include performing a pressure test procedure (step 502) to estimate the wound volume multiple times during wound treatment. Step 502 may include performing the process 400 multiple times (e.g., once per day) during wound treatment. Each time the process 400 is performed, the volume of the wound 114 may be estimated. Each estimate of the wound volume may be stored along with the time the estimate was obtained. The time and estimated wound volume pair may be stored as a data point in memory of the therapy device 102 and / or presented to the user as an output of the therapy device 102 (e.g., via the communication interface 124 or the user interface 126). In some embodiments, the estimated wound volume may be plotted as a function of time, as shown in FIG. 11.

[0126] Process 500 is shown to include determining healing progress based on changes in wound volume during wound treatment (step 504). Step 504 may include comparing a current estimate of wound volume to one or more previous estimates of wound volume to identify changes in wound volume. In some embodiments, step 504 includes determining a rate at which the wound 114 is healing based on changes in wound volume over time. In some embodiments, step 504 includes extrapolating or predicting a time at which the wound 114 will be completely healed based on a series of wound volume estimates. For example, step 504 may include predicting a time at which the estimated wound volume will reach zero (or another threshold) based on a series of wound volume estimates obtained in step 502.

[0127] 11-12, a graph 600 and a flowchart 700 illustrating application of the wound volume estimate are shown, according to an exemplary embodiment. The controller 118 may calculate a volume of dripped fluid 105 to be delivered to the wound 114 using the estimated wound volume (step 702). In some embodiments, the controller 118 calculates the volume of dripped fluid 105 to be delivered to the wound 114 by multiplying the estimated wound volume by a fluid drip factor. The fluid drip factor may be less than 1 (i.e., between 0 and 1) such that the calculated volume of dripped fluid 105 is less than the volume of the wound 114. In some embodiments, the fluid drip factor is between about 0.2 and about 0.8. However, it is contemplated that the fluid drip factor may have any value in various alternative embodiments.

[0128] In the graph 600, a line 602 represents the estimated volume of the wound 114 as a function of time, while a line 604 represents the calculated volume of dripped fluid 105 to be delivered to the wound 114 over time. At time t1, the estimated volume of the wound 114 is V4. The estimated wound volume V4 at time t1 can be multiplied by a fluid dripping factor F (e.g., F=0.8) to calculate the volume of dripped fluid 105 V3 to be delivered to the wound 114 at time t1 (i.e., V4*F=V3). As the wound 114 heals, the estimated volume of the wound 114 decreases, reaching a value of V2 at time t2. The estimated wound volume V2 at time t2 can be multiplied by a fluid dripping factor F to calculate the volume of dripped fluid 105 V1 to be delivered to the wound 114 at time t2 (i.e., V2*F=V1).

[0129] The controller 118 can then operate the pump to deliver the calculated volume of dripping fluid 105 to the wound 114 (step 704). Step 704 can include operating the dripping pump 122 to draw dripping fluid 105 from the dripping fluid canister 104 and deliver the dripping fluid 105 to the wound 114 via the tubes 109 and 108. In some embodiments, the calculated volume of dripping fluid 105 is also used to control the operation of the pneumatic pump 120. For example, the controller 118 can operate the pneumatic pump 120 to remove the volume of dripping fluid 105 from the wound 114 via the tube 110. The amount of time the pneumatic pump 120 operates can be a function of the volume of dripping fluid 105 delivered to the wound 114.

[0130] Wound Therapy Chart 13, a graph 800 is shown illustrating several stages of a wound therapy process, according to an exemplary embodiment. The wound therapy process illustrated in FIG. 13 may be performed by one or more components of therapy device 102, as previously described. Line 802 represents the negative pressure in the negative pressure circuit at each stage of the wound therapy process.

[0131] At time t0, the therapy device 102 begins operating the air pressure pump 120 to reduce the negative pressure in the negative pressure circuit during an initial drawdown phase 804, which occurs between times t0 and t1. At time t1, the negative pressure in the negative pressure circuit reaches approximately 125 mmHg below atmospheric pressure, and the air pressure pump 120 is deactivated.

[0132] Between times t1 and t2, the negative pressure in the negative pressure circuit is monitored using measurements from pressure sensors 130 and / or 113 during a seal verification phase 806. A substantial change in pressure between times t1 and t2 may indicate that the seal between the wound dressing 112 and the patient's skin is not airtight, whereas a substantially constant pressure between times t1 and t2 may indicate that the wound dressing 112 is properly sealed to the patient's skin.

[0133] At time t2, the air pressure pump 120 is operated until the negative pressure in the negative pressure circuit drops to approximately 200 mmHg below atmospheric pressure. When a negative pressure of 200 mmHg is reached, the air pressure pump 120 is deactivated and the wound volume determination step 808 is initiated. The air pressure pump 120 may be operated intermittently during step 808 to maintain the negative pressure at approximately 200 mmHg and to compensate for air leakage into the negative pressure circuit.

[0134] At time t3, the air pressure pump 120 is deactivated and the leak determination step 810 begins. Between times t3 and t4, the negative pressure in the negative pressure circuit is monitored to determine the rate at which air is leaking into the negative pressure circuit. At time t4, the air pressure pump 120 is activated again to reduce the negative pressure back to approximately 200 mmHg. The air pressure pump 120 may be operated intermittently between times t4 and t5 to maintain the negative pressure at approximately 200 mmHg and compensate for air leaking into the negative pressure circuit.

[0135] At time t5, the air pressure pump 120 is deactivated and the wound volume determination phase 812 begins. During the wound volume determination phase 812, the therapy device 102 may perform one or more of the pressure test procedures described with reference to Figures 6A-6D. The time range illustrated in graphs 200, 210, 220, and 230 may occur entirely between times t5 and t6 in graph 800.

[0136] At time t6, the air pressure pump 120 is activated to reduce the negative pressure to approximately 125 mmHg below atmospheric pressure during drawdown for the dripping phase 814. When a negative pressure of approximately 125 mmHg is reached at time t7, the air pressure pump 120 is deactivated. The air pressure pump 120 may be operated intermittently between times t7 and t8 to maintain the negative pressure at approximately 125 mmHg and to compensate for air leakage into the negative pressure circuit. Between times t7 and t8, the dripping fluid 105 may be delivered to the wound 114.

[0137] Configuration of an Exemplary Embodiment The construction and arrangement of the systems and methods as shown in the various exemplary embodiments are merely exemplary. Although only a few embodiments are detailed in this disclosure, many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of the various elements, parameter values, mounting arrangements, amounts of materials used, colors, orientations, etc.). For example, the positions of elements can be reversed or otherwise changed, and the nature or number of distinct elements can be altered or changed. Thus, all such modifications are intended to be included within the scope of this disclosure. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions, and arrangements of the exemplary embodiments without departing from the scope of the invention.

[0138] The present disclosure contemplates methods, systems, and program products on any machine-readable medium for performing various operations. The embodiments of the present disclosure can be implemented using existing computer processors, by dedicated computer processors for suitable systems incorporated for this or another purpose, or by hardwired systems. Embodiments within the scope of the present disclosure include program products including machine-readable media for carrying or storing machine-executable instructions or data structures. Such machine-readable media can be any available medium that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can include RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage, or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and that can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data that cause a general purpose computer, a special purpose computer, or a special purpose processing machine to perform a certain function or group of functions.

[0139] Although the figures show a particular order of method steps, the order of steps may differ from the order depicted. Also, two or more steps may be performed simultaneously or with partial concurrence. Such variations are dependent on the software and hardware systems selected and the designer's choices. All such variations are within the scope of this disclosure. Similarly, software implementations may be implemented with standard programming techniques using rule-based logic and other logic to implement the various connection, processing, comparison, and decision steps.

Claims

1. 1. A system for estimating wound volume, comprising: a controller communicatively coupled to the pump and to the pressure sensor, Applying a pressure stimulus to the negative pressure circuit; operating the pump to establish a negative pressure in the negative pressure circuit; applying the pressure stimulus after the negative pressure is established in the negative pressure circuit; Perform a pressure test procedure, including Observing the dynamic pressure response of the negative pressure circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor; and Estimating a wound volume of the wound based on the dynamic pressure response. The control device configured as described above 1. A system for estimating wound volume, comprising:

2. 10. The system of claim 1, wherein estimating the wound volume based on the dynamic pressure response comprises: determining values ​​for one or more parameters characterizing the dynamic pressure response; applying the values ​​of the one or more parameters as inputs to a model defining a relationship between the one or more parameters and the wound volume; A system comprising:

3. 3. The system of claim 2, wherein the model defining the relationship between the one or more parameters and the wound volume is a polynomial approximation model.

4. 3. The system of claim 2, wherein the model defining the relationship between the one or more parameters and the wound volume is a neural network.

5. 3. The system of claim 2, wherein the control device comprises: performing a training procedure that includes applying the pressure stimulus to a training circuit having a known volume; Observing the dynamic pressure response of the training circuit to the pressure stimulus using pressure measurements recorded by the pressure sensor; and Correlating the known volume with the dynamic pressure response of the training circuit. and generating the model defining the relationship between the one or more parameters and the wound volume by A system characterized by:

6. 6. The system of claim 5, wherein generating the model comprises: repeating the training procedure for a number of known volumes; observing the dynamic pressure response of the training circuit for each of the plurality of known volumes; generating a correlation between the plurality of known volumes and the dynamic pressure response of the training circuit; The system further comprising:

7. 2. The system of claim 1, wherein the control device comprises: performing the pressure test procedure, observing the dynamic pressure response, and estimating the wound volume multiple times during wound treatment; and Determining healing progress based on changes in wound volume during wound treatment. The system is configured as follows.

8. 2. The system of claim 1, wherein the control device comprises: determining a volume of a drip fluid to be delivered to the wound based on the estimated wound volume; and Operate the pump to deliver the volume of drip fluid to the wound. The system is configured as follows.

9. 9. The system of claim 8, wherein the controller is configured to determine the volume of drip fluid to deliver to the wound by multiplying the estimated wound volume by a fluid drip factor.

10. 10. The system of claim 9, wherein the fluid drip factor is less than 1 such that less than the entire wound volume is filled with the dripped fluid.

11. 10. The system of claim 9, wherein the fluid drip coefficient is from about 0.2 to about 0.8.

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