Mobile Negative Pressure Wound Therapy Device Configured for Start-Up Testing

Abstract

A mobile negative pressure wound therapy (NPWT) device includes an inlet adapted to be fluidly connected to a wound site, a canister fluidly connected to the inlet for collecting fluid from the wound site, a pump fluidly connected to the canister for establishing a negative pressure in the canister, a pressure sensor configured to sense pressure in the canister, and control circuitry for controlling operation of the NPWT device, the control circuitry configured to: initiate a test sequence for the NPWT device, acquire a first signal indicative of pressure in the canister, evaluate the first signal, and when the acquired first signal indicates a smaller magnitude of negative pressure compared to a predefined threshold pressure, control the pump to operate the pump for a predefined time period, acquire a second signal after the predefined time period, and proceed with the start-up test sequence, and when the acquired signal indicates a larger magnitude of negative pressure compared to the predefined threshold pressure, control the pump to operate the pump for a predefined time period without operating the pump.

Description

[Technical field]

[0001] The present invention relates to mobile negative pressure wound therapy (NPWT) devices and to methods for testing such NPWT devices. [Background technology]

[0002] Negative Pressure Wound Therapy (NPWT) is a technique that uses a negative pressure pump to apply negative pressure (i.e., pressure below atmospheric pressure) to the wound to promote healing of, for example, surgical, acute, and chronic wounds. NPWT techniques also allow for less external disturbance to the wound and allow for the removal of excess fluid from the wound site. In general, NPWT techniques have been primarily applied to patients in a hospital environment. However, recent product developments have made this technique available for use by patients in the home environment.

[0003] To make it easier and more comfortable for users to benefit from NPWT, mobile NPWT devices have recently been developed. For such NPWT devices to be truly mobile, it is practical to power the NPWT device with one or more batteries. Of course, operation of the NPWT device will eventually reduce the amount of energy stored in the battery (or batteries), necessitating replacement of the battery with a fully charged battery. To reduce the risk of injury or discomfort to the user, it may be desirable to perform a start-up test sequence on the NPWT device after a battery change, and at other times. Summary of the Invention

[0004] It is an object of the present invention to provide an improved NPWT device and, in particular, to provide a method for testing the NPWT device that enhances start-up testing for the NPWT device.

[0005] Thus, according to a first aspect of the present invention there is provided a mobile Negative Pressure Wound Therapy (NPWT) device comprising: an inlet adapted to be fluidly connected to a wound site; a canister fluidly connected to the inlet for collecting liquid from the wound site; a pump fluidly connected to the canister for establishing negative pressure in the canister; a pressure sensor configured to sense pressure in the canister; and control circuitry for controlling operation of the NPWT device. The control circuit receives a request to activate the NPWT device; in response to the activation request, initiates a start-up test sequence for the NPWT device; acquires a first signal from the pressure sensor indicative of a pressure in the canister; evaluates the acquired first signal from the pressure sensor; when the acquired first signal indicates a lesser degree of negative pressure compared to a predefined threshold pressure, controls the pump to operate the pump for a predefined period of time; acquires a second signal from the pressure sensor after the predefined period of time; proceeds with the start-up test sequence; and selects a first criterion from the set of predefined criteria for failure to satisfy at least one criterion. The NPWT device is configured to allow the NPWT device to transition to a therapy mode unless the NPWT device fails at least one test in the start-up test sequence, to proceed with the start-up test sequence without controlling the pump to operate the pump for a predefined period of time when the acquired signal indicates a greater degree of negative pressure compared to a predefined threshold pressure, and to allow the NPWT device to transition to a therapy mode unless the NPWT device fails at least one test in the start-up test sequence due to failure to satisfy at least one criterion in a set of predefined criteria.

[0006] It should be noted that the start-up test sequence may also include a decision to abort the start-up test sequence in the event of a failed test. Thus, proceeding with the start-up test sequence may include aborting the start-up test sequence.

[0007] It should also be noted that the pressure sensor need not be configured to directly sense the pressure within the canister, but may be configured to sense pressure elsewhere within the NPWT device, so long as the sensed pressure is indicative of the pressure within the canister. Additionally, the pressure sensor may sense another characteristic, such as force or deflection, based on which a pressure change may be inferred.

[0008] The wake-up request may be any instruction requesting that the NPWT device be ready for treatment. For example, the wake-up request may be a power-up (insertion of one or more batteries), or pressing an activation button, or a reset operation, etc.

[0009] When reference is made to a "greater degree of negative pressure compared to a predefined threshold pressure," it will be understood that "negative pressure" is relative to atmospheric pressure, and that this situation is equivalent to a lesser absolute pressure compared to a predefined absolute threshold pressure.

[0010] The present invention is based on the recognition that there are possible use cases where negative pressure may exist in the NPWT system before the pump is operated during a start-up test, and that it would be desirable not to operate the pump under such circumstances. It is not unreasonable to assume that care staff or users do not always follow all instructions regarding the operation of the NPWT system. For example, a plausible but undesirable use case may be that the tubing fluidly connected to the outlet of the chamber at the wound site is interrupted before a battery change or before switching to a new NPWT device, and is not interrupted after connecting to the inlet of the NPWT device after a start-up test is performed. In such a case, negative pressure will exist in the canister of the NPWT device before the start-up test sequence is initiated. In such cases, and other similar cases, the inventors have found that it would be desirable to avoid performing the usual tests on the pressure sensor and pump during the start-up test sequence, but instead proceed with the start-up test sequence if the findings are that the pressure is a greater degree of negative pressure compared to a predefined threshold pressure. The predefined threshold pressure may be, for example, atmospheric pressure, in other words, zero negative pressure. Alternatively, the predefined threshold pressure may be a predefined non-zero negative pressure.

[0011] This reduces the risk of the start-up test causing discomfort or even harm to the user after the start-up test is completed and the tube is unblocked.

[0012] Furthermore, in at least most use cases, obtaining a signal from the pressure sensor indicating a greater degree of negative pressure compared to a predefined threshold pressure indicates that the pressure sensor is functional and that the pump has recently been operated, and it can be concluded that there is less risk associated with allowing the NPWT device to transition to a treatment mode compared to operating the pump for a predefined period of time.

[0013] The predefined time period may be at least 0.5 seconds and may advantageously be close to 1 second, for example approximately 0.9 seconds.

[0014] Advantageously, the first signal may be obtained from the pressure sensor prior to any operation of the pump included in the start-up test sequence.

[0015] According to various embodiments, the control circuitry may be further configured to evaluate a second signal acquired from the pressure sensor when the first acquired signal indicates a lesser degree of negative pressure compared to a predefined threshold pressure, and determine that the NPWT device has met a criterion in a set of predefined criteria when the second signal indicates negative pressure within a predefined time period. For example, the control circuitry may be configured to determine that the NPWT device has met a criterion when the second signal acquired from the pressure sensor indicates a greater degree of negative pressure (lesser absolute pressure value) compared to that indicated by the first signal acquired from the pressure sensor.

[0016] According to an embodiment, the control circuitry may be further configured to determine that the NPWT has met a criterion in a set of predefined criteria when the acquired first signal indicates a greater degree of negative pressure compared to a predefined threshold pressure, without controlling the pump to operate the pump for a predefined period of time.

[0017] In an embodiment, the control circuitry may be further configured to repeatedly acquire a signal from the pressure sensor when controlling and operating the pump after the NPWT device is allowed to transition to a treatment mode, evaluate the signal acquired from the pressure sensor, and determine that the pressure sensor is not functioning when the signal acquired from the pressure sensor is consistently at a minimum value that can be acquired from the pressure sensor, or when the signal acquired from the pressure sensor is consistently at a maximum value that can be acquired from the pressure sensor, or when the signal acquired from the pressure sensor alternates between a minimum and a maximum value, or when the signal acquired from the pressure sensor indicates an increasing pressure over time.

[0018] These embodiments cover two important failure modes that are likely to indicate that the pressure sensor is not functioning. In the first failure mode, the connection between the pump and the control circuit contained within the NPWT device may be interrupted, and in the second failure mode, the amplifier circuitry involved in the pressure sensing may have a problem. It has been found that when the connection is interrupted, the interrupted electrical conductor connected to the control circuitry may act as an antenna, and the signal that the control circuitry gets may be a minimum signal, such as 0V, or a maximum signal, such as 3.3V (or any other relevant maximum voltage value in the NPWT device). It has been found that a problem in the amplifier circuitry may result in an inverted pressure signal curve that indicates an increase in absolute pressure when in fact the absolute pressure is decreasing (i.e., a greater degree of negative pressure compared to atmospheric pressure).

[0019] According to various embodiments, the mobile NPWT device may further include a battery and a speaker, and the control circuit may be further configured to control the speaker to operate the speaker to emit sound, measure a voltage drop of the battery when the speaker is operated, and determine that the NPWT device has satisfied a criterion in a set of predefined criteria when the battery voltage drop when the speaker is operated is less than a predetermined value.

[0020] According to a second aspect of the present invention, there is provided a method for testing a mobile Negative Pressure Wound Therapy (NPWT) device, the NPWT device including an inlet adapted to be fluidly connected to a wound site, a canister fluidly connected to the inlet, the canister for collecting fluid from the wound site, a pump fluidly connected to the canister, the pump for establishing a negative pressure in the canister, and a pressure sensor configured to sense a pressure in the canister, the method comprising the steps of receiving a start-up request for the NPWT device, initiating a start-up test for the NPWT device in response to the start-up request, the start-up test including a start-up test sequence, acquiring from the pressure sensor a first signal indicative of a pressure in the canister, evaluating the first signal acquired from the pressure sensor, and controlling the pump to increase the pressure in the canister to a predefined threshold pressure when the acquired first signal indicates a lesser degree of negative pressure compared to a predefined threshold pressure. the step of controlling the pump to operate for a predefined period of time; obtaining a second signal from the pressure sensor after the predefined period of time; proceeding with the start-up test sequence; determining that the NPWT device has passed the start-up test unless the NPWT device has failed at least one test in the start-up test sequence due to failure to satisfy at least one criterion in the set of predefined criteria; when the obtained signal indicates a greater degree of negative pressure compared to the predefined threshold pressure, controlling the pump to proceed with the start-up test sequence without operating the pump for the predefined period of time; and determining that the NPWT device has passed the start-up test unless the NPWT device has failed at least one test in the start-up test sequence due to failure to satisfy at least one criterion in the set of predefined criteria.

[0021] The variations and advantages of this second aspect of the invention are in many respects similar to those discussed above in relation to the first aspect.

[0022] According to a third aspect of the invention there is provided a computer program comprising instructions which, when executed on a controller included in a NPWT device according to an embodiment of the first aspect, cause the controller to perform each step of the method according to an embodiment of the second aspect.

[0023] The computer program may be stored on a non-transitory computer readable data carrier.

[0024] A mobile NPWT device according to an embodiment of the present invention may be included within a negative pressure wound therapy (NPWT) system, which includes a chamber to be placed at a wound site and for establishing negative pressure, and further includes a chamber having an outlet and a tube fluidly connecting the outlet of the chamber to an inlet of the NPWT device.

[0025] In summary, the present invention is a mobile negative pressure wound therapy (NPWT) device including an inlet for fluidly connecting to a wound site, a canister fluidly connected to the inlet for collecting fluid from the wound site, a pump fluidly connected to the canister for establishing a negative pressure in the canister, a pressure sensor configured to sense pressure in the canister, and a control circuit for controlling operation of the NPWT device, the control circuit configured to initiate a test sequence for the NPWT device, obtain a first signal indicative of pressure in the canister, evaluate the first signal, control the pump to operate the pump for a predefined time period when the obtained first signal indicates a smaller degree of negative pressure compared to a predefined threshold pressure, obtain a second signal after the predefined time period, and proceed with the start-up test sequence, and when the obtained signal indicates a larger degree of negative pressure compared to the predefined threshold pressure, proceed with the start-up test sequence without controlling the pump to operate the pump for the predefined time period. [Brief description of the drawings]

[0026] These and other aspects of the invention will now be described in more detail with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. [Figure 1] FIG. 1 is an illustration of an exemplary mobile NPWT system according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a flow chart illustrating a first exemplary configuration of a mobile NPWT device according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a flow chart illustrating a second configuration example of a mobile NPWT device in accordance with an embodiment of the present invention. [Figure 4] FIG. 4 is a flow chart illustrating a third example configuration of a mobile NPWT device in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The present disclosure will now be described more fully with reference to the accompanying drawings, which illustrate currently preferred embodiments of the present disclosure. However, the present disclosure may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein, but rather these embodiments are provided for the sake of thoroughness and completeness so as to fully convey the scope of the present disclosure to those skilled in the art. Like reference numerals refer to like elements throughout all drawings.

[0028] Referring now to the drawings and in particular to FIG. 1, a negative pressure wound therapy (NPWT) system 1 is conceptually illustrated including a mobile NPWT device 3 according to an exemplary embodiment of the present invention. The NPWT system 1 further includes a wound cover 5 having a chamber 6 disposed at the wound site. The wound cover 5 having the chamber 6 is configured to form an enclosed space 7 at or around the user's wound site, the enclosed space being defined in part by a wound surface 9, e.g., the user's skin. As shown generally in FIG. 1, the chamber 6 has an inlet 8 and an outlet 10. The outlet 10 of the chamber 6 is fluidly connected to the mobile NPWT device 3 using a tube 11, and the inlet 8 of the chamber 6 is fluidly connected to the environment (the air around the user) via a filter (not visible in FIG. 1) to provide a continuous leak of air into the chamber 6. The tube 11 may be any suitable flexible tube manufactured from an elastomeric and / or polymeric material.

[0029] As shown diagrammatically in FIG. 1, the NPWT device 3 includes a negative pressure pump 13, which is configured to establish a negative pressure when the negative pressure pump 13 is controlled to operate. The negative pressure pump 13 may be any type of pump that is biocompatible and maintains or extracts an appropriate therapeutic vacuum level. Preferably, the negative pressure level to be achieved may range from about -20 mmHg to about -300 mmHg. In possible embodiments of the present disclosure, a negative pressure range of about -80 mmHg to about -140 mmHg may be used. In possible embodiments of the present invention, the negative pressure pump 13 is a diaphragm type or a peristaltic type pump.

[0030] The negative pressure pump 13 is fluidly connected to the canister 15, which also forms part of the NPWT device 3. The canister 15 may be formed, for example, from molded plastic or the like, and may possibly be a removable component of the NPWT device 3. The canister 15 may preferably be at least partially transparent / translucent, which allows the interior of the canister 15 to be viewed and may assist a user in determining the remaining volume of the canister 15.

[0031] An inlet port 17 is formed in the canister 15 to allow connection to the tubing 11. The inlet port 17 may also be formed elsewhere on the NPWT device 3, but still be fluidly connected to the canister 15. The connection between the inlet port 17 and the tubing 11 is a sealed connection, ensuring that there are no leaks at the inlet port 17 during normal operation of the NPWT device 3. The tubing 11 is preferably releasably connected to the inlet port 17 by conventional means, including friction fit, bayonet coupling, snap fit, barbed connector, or the like. The inlet port 17 may be molded / formed from the same material forming the canister 15 and / or at the same time as the canister 15. A similar sealed connection (e.g., using a flanged insulator / "O-ring") may be formed between the canister 15 and the negative pressure pump 13.

[0032] The NPWT device 3 further includes a battery 19 for powering the NPWT device 3. The battery 19 is preferably of a rechargeable type, but may alternatively be disposable. Specially constructed battery packs may be used in connection with some embodiments of the present disclosure.

[0033] The NPWT device 3 also includes a controller 21 for controlling the operation of the mobile NPWT device 3, at least one pressure sensor 23 configured to sense the pressure within the canister 15, and a speaker 24 for providing user feedback and / or warnings.

[0034] A controller 21, powered by a battery 19 and coupled to the pump 13, pressure sensor 23 and speaker 24, may include a microprocessor, a microcontroller, a programmable digital signal processor, or another programmable device. The controller 21 may alternatively include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. In the case where the controller 21 includes a programmable device, such as a microprocessor, microcontroller, or programmable digital signal processor as described above, the processor may further include computer executable code for controlling the operation of the programmable device.

[0035] In use of the NPWT device 3, the wound cover 5 is placed on the wound site of a user to form a sealed space 7. A tube 11 is provided to fluidly connect an outlet 10 of the chamber 6 in the wound cover 5 to an inlet port 17 of the NPWT device 3. The mobile NPWT device 3 may then be activated to begin treatment, for example by a user pressing a start / pause button (not shown in FIG. 1 ). In response to this request to begin a therapeutic procedure, the controller 21 may control the negative pressure pump 13 to operate the negative pressure pump 13. In operation, the negative pressure pump 13 will begin to evacuate air through the canister 15, the inlet port 17, the tube 11, and the sealed space 7 formed by the chamber 6 in the wound cover 5. Thus, a negative pressure is generated within the sealed space 7. If liquid is formed at the wound site, this liquid from the wound site can be at least partially "extracted" from the wound site through the tube 11 and the inlet port 17 into the canister 15 based on the continuous limited leakage provided by the inlet 8 of the chamber 6. The amount of liquid (sometimes called exudate) extracted from the wound and collected in the canister will depend on the type of wound being treated and the type of wound dressing used. For example, if an absorbent dressing is used, the liquid can be absorbed and collected in both the canister and the wound dressing, whereas if a dressing with no or little absorption capacity is used, most or all of the liquid from the wound site may be collected in the canister. A suitable filter member (not shown in FIG. 1) may be placed between the canister 15 and the negative pressure pump 13 to ensure that no liquid can pass from the canister 15 to the negative pressure pump 13.

[0036] As described above, the mobile NPWT device 3 requires a charged battery pack 19 to operate, and when the battery pack 19 is depleted, the battery pack must be replaced. After the battery is replaced, or when the NPWT device 3 is replaced with a new one, the NPWT device 3 is tested to reduce the risk of malfunction during subsequent treatments.

[0037] To this end, the controller 21 in the NPWT device 3 according to embodiments of the present invention may be configured to perform a test procedure according to embodiments of the present invention. In particular, processing circuitry provided in the controller 21 may be programmed to perform the steps according to various embodiments of the method according to the present invention.

[0038] Hereinafter, an embodiment of the present invention will be described with reference to the illustration in FIG. 1 as well as the flow charts in FIG. 2, FIG. 3, and FIG.

[0039] 2 is a flow chart illustrating a first example configuration of a mobile NPWT device in accordance with an embodiment of the present invention. Referring to FIG 2, a controller 21 of the NPWT device 3 may be configured to receive 100 an activation request, which may be provided, for example, in the form of a predefined operation of a button or reset switch, or in the form of powering on after replacing a battery pack 19.

[0040] In response to the wake-up request, the controller 21 is configured to initiate 101 a wake-up test sequence for the NPWT device 3 .

[0041] As part of the start-up test sequence, the controller 21 is configured to obtain 102 from the pressure sensor 23 a first signal P 1 indicative of the pressure within the canister 15 .

[0042] The control device 21 is configured to evaluate 103 a first signal P1 obtained from the pressure sensor 23, the first signal P1 being greater than or equal to a predefined threshold pressure P thWhen the first signal P2 indicates a smaller degree of negative pressure compared to the first signal P1, the controller 21 is configured to control the pump 13 to operate the pump 13 for a predefined period of time T (104) and to obtain 105 a second signal P2 indicative of the pressure in the canister 15 after the predefined period of time T.

[0043] The controller 21 is configured to evaluate 106 a second signal P2 obtained from the pressure sensor 23 after a predefined time period T, and when the second signal P2 indicates that the pressure did not become a greater degree of negative pressure, or when the pressure did not become a sufficiently negative pressure degree to indicate that the pump 13 is operating as desired, the controller 21 may be configured to determine 107 that the NPWT device 3 has failed the start-up test.

[0044] On the other hand, when the second signal P2 indicates that the pressure in the canister 15 has become more negative (or has become sufficiently negative) compared to the pressure indicated by the first signal P1, the controller 21 is configured to proceed 108 with the start-up test sequence and to determine 109 whether the NPWT device 3 has failed 110 or passed the start-up test. If the controller 21 determines that the NPWT device 3 has passed the start-up test, the controller 21 may be configured to allow 111 the NPWT device 3 to transition to a treatment mode.

[0045] When the NPWT device 3 is authorized to transition to the therapy mode, the controller 21 may transition the NPWT device 3 directly to the therapy mode or may be configured to transition in response to a user request, such as a predefined operation of a user interface, such as a button or touch screen. The predefined time period T may advantageously be at least 500 ms to ensure a reliable indication of whether the pump 13 and / or pressure sensor 23 are operational, regardless of the configuration of the NPWT system 1. More advantageously, the predefined time period may be at least 700 ms, such as 900 ms.

[0046] After the controller 21 allows the NPWT device 3 to transition to a treatment mode, or as part of a start-up test sequence, the controller 21 may be configured to perform additional steps to test the operation of the pump 13 and / or the pressure sensor 23 of the NPWT device 3. A second such example configuration of a mobile NPWT device in accordance with an embodiment of the present invention is illustrated generally in FIG. 3. Referring to FIG. 3, the controller 21 of the NPWT device 3 may thus be additionally configured to control the pump 13 to operate 200 the pump 13, and further to repeatedly acquire 201 a signal P(t) from the pressure sensor 23 during operation of the pump 13.

[0047] Upon or after acquisition of the signal P(t) from the pressure sensor 23, the control device 21 may be configured to determine whether at least one of two failure modes can be identified by evaluating the signal P(t) from the pressure sensor 23. The signal P(t) obtained from the pressure sensor 23 may be determined to be equal to or greater than the minimum value P(t) that can be obtained from the pressure sensor 23. min At the time 202, it is determined that the signal P(t) obtained from the pressure sensor 23 is always at the maximum value P(t) that can be obtained from the pressure sensor 23. max At the time 202, it is determined that the signal P(t) obtained from the pressure sensor 23 is always at a minimum value P min and the maximum value P maxWhen it is determined 202 that the signal P(t) obtained from the pressure sensor 23 indicates an increasing pressure over time, the controller 21 may be configured to identify a first failure mode indicative of a connection being broken between the controller 21 and the pressure sensor 23. When it is determined 203 that the signal P(t) obtained from the pressure sensor 23 indicates an increasing pressure over time, the controller 21 may be configured to identify a second failure mode indicative of a malfunction of an amplifier circuit within the pressure sensor 23.

[0048] When any of these failure modes are identified by the controller 21, the controller is configured to determine 204 that the signal P(t) from the pressure sensor 23 is unreliable and therefore the pressure sensor 23 should be classified as faulty. In such a case, the controller 21 may be configured to take action to prevent the NPWT3 from entering a therapy mode or to take action to discontinue therapy. The controller 21 may also be configured to provide an indication to the user via a user interface.

[0049] When no failure mode is identified by the controller 21, the controller is configured to determine 205 that the pressure sensor 23 is operating as intended, and may further allow the NPWT3 to enter or continue in a therapy mode.

[0050] As part of the start-up test sequence, the controller 21 may be configured to perform additional steps to test the operation of the NPWT device 3. A third such configuration example of a mobile NPWT device 3 according to an embodiment of the present invention is illustrated diagrammatically in FIG. 4. Referring to FIG. 4, the controller 21 of the NPWT device 3 may thus be additionally configured to control the speaker 24 to emit sound 300. Because the speaker 24 is one of the most power-consuming components of the NPWT device 3, this may be an efficient way to assess the health of the battery pack 19. Following the instruction, the depleted battery pack 19 needs to be replaced with a fully charged battery pack 19 or a new battery pack 19. However, if the instruction is not followed, the depleted battery pack 19 may be replaced with another battery pack 19 that is at least partially depleted.

[0051] Thus, the controller 21 may be configured to measure 301 the battery voltage drop ΔV due to operation of the speaker 24 .

[0052] The control device 21 calculates the measured battery voltage drop ΔV by comparing it with a predefined threshold voltage drop ΔV th and evaluating 302 the battery voltage drop during operation of the speaker relative to a predefined threshold voltage drop ΔV th When the threshold is less than 100%, the NPWT device may be configured to determine 303 that the start-up test sequence can proceed by determining that a criterion in a set of predefined criteria has been met.

[0053] Instead, the measured battery voltage drop ΔV is compared to a predefined threshold voltage drop ΔV th When the controller 21 determines that the threshold voltage Vcc is greater than Vcc, the controller 21 may be configured to determine 304 that the NPWT device 3 has failed the start-up test.

[0054] In the claims, the term "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The inventions disclosed herein include the following: [Aspect 1] 1. A mobile negative pressure wound therapy (NPWT) device, comprising: an inlet adapted to be in fluid communication with the wound site; a canister in fluid communication with the inlet, the canister for collecting liquid from the wound site; a pump in fluid communication with the canister, the pump for establishing a negative pressure within the canister; a pressure sensor configured to sense pressure within the canister; a control circuit for controlling the operation of the NPWT device; Including, The control circuit includes: receiving a request to activate the NPWT device; initiating a start-up test sequence for the NPWT device in response to the start-up request; obtaining a first signal from the pressure sensor indicative of pressure within the canister; evaluating the first signal obtained from the pressure sensor; When the acquired first signal indicates a smaller degree of negative pressure compared to a predefined threshold pressure, controlling the pump to operate the pump for a predefined period of time; obtaining a second signal from the pressure sensor after the predefined period of time; proceeding with the start-up test sequence; permitting the NPWT device to transition to a therapy mode unless the NPWT device fails at least one test in the start-up test sequence due to failure to satisfy at least one criterion in a set of predefined criteria; when the acquired signal indicates a greater degree of negative pressure compared to the predefined threshold pressure; controlling the pump to proceed with the start-up test sequence without operating the pump for the predefined period of time; permitting the NPWT device to transition to a therapy mode unless the NPWT device fails at least one test in the start-up test sequence due to failure to satisfy at least one criterion in a set of predefined criteria; 1. A mobile negative pressure wound therapy (NPWT) device configured to: [Aspect 2] When the acquired first signal indicates a smaller degree of negative pressure compared to the predefined threshold pressure, the control device evaluating the second signal obtained from the pressure sensor; and determining that the NPWT device has met a criterion in the set of predefined criteria when the second signal indicates negative pressure within a predefined time period; 2. The NPWT apparatus of embodiment 1, further configured to: [Aspect 3] When the acquired first signal indicates a greater degree of negative pressure compared to the predefined threshold pressure, the control device 3. The NPWT device of aspect 1 or 2, further configured to determine that the NPWT has met a criterion in the set of predefined criteria without controlling the pump to operate the pump for the predefined period of time. [Aspect 4] The control device, after the NPWT device is permitted to transition to a therapy mode, repeatedly acquiring a signal from the pressure sensor; evaluating the signal obtained from the pressure sensor; and determining that the pressure sensor is not functioning when the signal obtained from the pressure sensor is always at a minimum value obtainable from the pressure sensor, or when the signal obtained from the pressure sensor is always at a maximum value obtainable from the pressure sensor, or when the signal obtained from the pressure sensor alternates between the minimum and maximum values, or when the signal obtained from the pressure sensor indicates a constant pressure or an increasing pressure over time during operation of the pump; 4. The NPWT apparatus of any one of aspects 1 to 3, further configured to: [Aspect 5] The NPWT device further includes a battery and a speaker, and the control circuitry includes: controlling the speaker to operate the speaker to emit sound; measuring a voltage drop across the battery when the speaker is in operation; determining that the NPWT device has met a criterion in the set of predefined criteria when the voltage drop of the battery during operation of the speaker is less than a predetermined value; 5. The NPWT apparatus of any one of aspects 1 to 4, further configured to: [Aspect 6] 1. A method for testing a mobile negative pressure wound therapy (NPWT) device, comprising: wherein the NPWT device includes an inlet to be fluidly connected to a wound site, a canister fluidly connected to the inlet, the canister for collecting liquid from the wound site, a pump fluidly connected to the canister, the pump for establishing a negative pressure within the canister, and a pressure sensor configured to sense pressure within the canister; The method comprises: receiving a request to activate the NPWT device; initiating a start-up test including a start-up test sequence for the NPWT device in response to the start-up request; obtaining a first signal from the pressure sensor indicative of the pressure within the canister; evaluating the first signal obtained from the pressure sensor; When the acquired first signal indicates a smaller degree of negative pressure compared to a predefined threshold pressure, controlling the pump to operate the pump for a predefined period of time; obtaining a second signal from the pressure sensor after the predefined period of time; proceeding with the start-up test sequence; determining that the NPWT device has passed the start-up test unless the NPWT device failed at least one test in the start-up test sequence due to failure to meet at least one criterion in a predefined set of criteria; when the acquired signal indicates a greater degree of negative pressure compared to the predefined threshold pressure; controlling the pump to proceed through the start-up test sequence without operating the pump for the predefined period of time; determining that the NPWT device has passed the start-up test unless the NPWT device failed at least one test in the start-up test sequence due to failure to satisfy at least one criterion in the predefined set of criteria; 1. A method for testing a movable negative pressure wound therapy (NPWT) device, comprising: [Aspect 7] The method comprises: evaluating the second signal obtained from the pressure sensor; determining that the NPWT device has met a criterion in the set of predefined criteria when the second signal indicates negative pressure within a predefined time period; The method of embodiment 6, further comprising: [Aspect 8] When the acquired first signal indicates a greater degree of negative pressure compared to the predefined threshold pressure, the method further comprises: 8. The method of claim 6 or 7, further comprising determining that the NPWT has met a criterion in the set of predefined criteria without controlling the pump to operate the pump for the predefined period of time. [Aspect 9] The method is performed after it is determined that the NPWT device has passed the start-up test. repeatedly acquiring a signal from the pressure sensor; evaluating the signal obtained from the pressure sensor; determining that the pressure sensor is not functioning when the signal obtained from the pressure sensor is consistently at a minimum value obtainable from the pressure sensor, or when the signal obtained from the pressure sensor is consistently at a maximum value obtainable from the pressure sensor, or when the signal obtained from the pressure sensor alternates between the minimum and maximum values, or when the signal obtained from the pressure sensor indicates a constant or increasing pressure over time during operation of the pump; 9. The method of any one of aspects 6 to 8, further comprising: [Aspect 10] When the mobile NPWT device further includes a battery and a speaker, the start-up test sequence includes: controlling the speaker to operate the speaker to emit sound; measuring a voltage drop across the battery when the speaker is in operation; determining that the NPWT device has met a criterion in the set of predefined criteria when the voltage drop of the battery during operation of the speaker is less than a predetermined value; 10. The method of any one of aspects 6 to 9, further comprising: [Aspect 11] A computer program comprising: A computer program comprising instructions that, when executed on a controller included in the NPWT device of example 1, cause the controller to perform each step of the method of example 6. [Aspect 12] 1. A negative pressure wound therapy (NPWT) system comprising: a chamber to be placed at a wound site, said chamber for establishing negative pressure, said chamber having an outlet; NPWT device according to any one of aspects 1 to 5; a tube fluidly connecting the outlet of the chamber and the inlet of the NPWT device; Negative Pressure Wound Therapy (NPWT) systems, including: [Aspect 13] 13. The NPWT system of claim 12, wherein the chamber further comprises an inlet fluidly connected to the surroundings through a filter and for providing a continuous leak of air into the chamber.

Claims

1. 1. A mobile negative pressure wound therapy (NPWT) device, comprising: an inlet adapted to be in fluid communication with the wound site; a canister in fluid communication with the inlet, the canister for collecting liquid from the wound site; a pump in fluid communication with the canister, the pump for establishing a negative pressure within the canister; a pressure sensor configured to sense pressure within the canister; A control device for controlling the operation of the NPWT device; Including, The control device includes: receiving a request to activate the NPWT device; initiating a start-up test sequence for the NPWT device in response to the start-up request; obtaining a first signal from the pressure sensor indicative of a pressure within the canister; evaluating the first signal obtained from the pressure sensor; When the acquired first signal indicates a smaller degree of negative pressure compared to a predefined threshold pressure, controlling the pump to operate the pump for a predefined period of time; obtaining a second signal from the pressure sensor after the predefined period of time; proceeding with the start-up test sequence; permitting the NPWT device to transition to a therapy mode unless the NPWT device has failed at least one test in the start-up test sequence due to failure to satisfy at least one criterion in a set of predefined criteria; when the acquired first signal indicates a greater degree of negative pressure compared to the predefined threshold pressure; controlling the pump to proceed with the start-up test sequence without operating the pump for the predefined period of time; permitting the NPWT device to transition to a therapy mode unless the NPWT device has failed at least one test in the start-up test sequence due to failure to satisfy at least one criterion in a set of predefined criteria; A mobile negative pressure wound therapy (NPWT) device configured to:

2. When the acquired first signal indicates a smaller degree of negative pressure compared to the predefined threshold pressure, the control device: evaluating the second signal obtained from the pressure sensor; and determining that the NPWT device has met a criterion in the set of predefined criteria when the second signal indicates negative pressure within a predefined time period; The NPWT apparatus of claim 1 , further configured to:

3. When the acquired first signal indicates a greater degree of negative pressure compared to the predefined threshold pressure, the control device 3. The NPWT device of claim 1 or 2, further configured to determine that the NPWT device has satisfied one criterion in the set of predefined criteria without controlling the pump to operate the pump for the predefined period of time.

4. The control device, after the NPWT device is permitted to transition to a treatment mode, repeatedly acquiring a signal from the pressure sensor; evaluating the signal obtained from the pressure sensor; and determining that the pressure sensor is not functioning when the signal obtained from the pressure sensor is always at a minimum value obtainable from the pressure sensor, or when the signal obtained from the pressure sensor is always at a maximum value obtainable from the pressure sensor, or when the signal obtained from the pressure sensor alternates between the minimum and maximum values, or when the signal obtained from the pressure sensor indicates a constant pressure or an increasing pressure over time during operation of the pump; The NPWT apparatus of claim 1 , further configured to:

5. The NPWT device further includes a battery and a speaker, and the control device further includes: controlling the speaker to operate the speaker to emit sound; measuring a voltage drop across the battery when the speaker is in operation; determining that the NPWT device has satisfied a criterion in the set of predefined criteria when the voltage drop of the battery during operation of the speaker is less than a predetermined value; The NPWT apparatus of claim 1 , further configured to:

6. 1. A method for testing a mobile negative pressure wound therapy (NPWT) device, comprising: wherein the NPWT device includes an inlet to be fluidly connected to a wound site, a canister fluidly connected to the inlet, the canister for collecting liquid from the wound site, a pump fluidly connected to the canister, the pump for establishing a negative pressure within the canister, and a pressure sensor configured to sense pressure within the canister; The method comprises: A controller receiving a request to activate the NPWT device; the controller initiating a start-up test including a start-up test sequence for the NPWT device in response to the start-up request; the controller obtaining a first signal from the pressure sensor indicative of the pressure within the canister; the controller evaluating the first signal obtained from the pressure sensor; When the acquired first signal indicates a smaller degree of negative pressure compared to a predefined threshold pressure, the controller controlling the pump to operate the pump for a predefined period of time; the controller obtaining a second signal from the pressure sensor after the predefined period of time; the controller proceeding with the start-up test sequence; determining by the controller that the NPWT device has passed the start-up test unless the NPWT device has failed at least one test in the start-up test sequence due to failure to satisfy at least one criterion in a predefined set of criteria; when the acquired first signal indicates a greater degree of negative pressure compared to the predefined threshold pressure; the controller controlling the pump to proceed with the start-up test sequence without operating the pump for the predefined period of time; the controller determining that the NPWT device has passed the start-up test unless the NPWT device has failed at least one test in the start-up test sequence due to failure to satisfy at least one criterion in the predefined set of criteria; 1. A method for testing a mobile negative pressure wound therapy (NPWT) device, comprising:

7. The method comprises: the controller evaluating the second signal obtained from the pressure sensor; when the second signal indicates negative pressure within a predefined time period, the controller determines that the NPWT device has met a criterion in the set of predefined criteria; The method of claim 6 further comprising:

8. When the acquired first signal indicates a greater degree of negative pressure compared to the predefined threshold pressure, the method further comprises:

8. The method of claim 6 or 7, further comprising the step of the control device determining that the NPWT device has satisfied a criterion in the set of predefined criteria without controlling the pump to operate the pump for the predefined period of time.

9. The method is performed after it is determined that the NPWT device has passed the start-up test. the controller repeatedly acquiring a signal from the pressure sensor; the controller evaluating the signal obtained from the pressure sensor; the controller determining that the pressure sensor is not functioning when the signal obtained from the pressure sensor is consistently at a minimum value obtainable from the pressure sensor, or when the signal obtained from the pressure sensor is consistently at a maximum value obtainable from the pressure sensor, or when the signal obtained from the pressure sensor alternates between the minimum and maximum values, or when the signal obtained from the pressure sensor indicates a constant or increasing pressure over time during operation of the pump; The method of claim 6 , further comprising:

10. If the mobile NPWT device further includes a battery and a speaker, the start-up test sequence includes: The control device controls the speaker to operate the speaker to emit sound; the control device measuring a voltage drop of the battery during operation of the speaker; when the voltage drop of the battery during operation of the speaker is less than a predetermined value, the control device determines that the NPWT device has satisfied a criterion in the set of predefined criteria; The method of claim 6 , further comprising:

11. A computer program comprising:

7. A computer program comprising instructions which, when executed on a controller contained within an NPWT apparatus as claimed in claim 1, cause said controller to carry out each of the steps of the method as claimed in claim 6.

12. 1. A negative pressure wound therapy (NPWT) system comprising: a chamber to be placed at a wound site, said chamber for establishing negative pressure, said chamber having an outlet; 6. A NPWT device according to any one of claims 1 to 5; a tube fluidly connecting the outlet of the chamber and the inlet of the NPWT device; 1. A negative pressure wound therapy (NPWT) system comprising:

13. 13. The NPWT system of claim 12, wherein the chamber further comprises an inlet fluidly connected to the surroundings through a filter for providing a continuous leak of air into the chamber.

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