Mobile negative pressure wound therapy device configured for initiation testing

Abstract

A mobile negative pressure wound therapy (NPWT) device, the NPWT device comprising: an inlet 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 a negative pressure in the canister; a pressure sensor arranged to sense a pressure in the canister; and a control circuit for controlling operation of the NPWT device. The control circuit is configured to: initiate a test sequence for the NPWT device; acquire a first signal indicative of the pressure in the canister; evaluate the first signal; when the acquired first signal is indicative of a pressure that is less negative than a predetermined threshold pressure: control the pump to operate for a predetermined time period; acquire a second signal after the predetermined time period; continue with the start-up test sequence; and when the acquired signal is indicative of a pressure that is more negative than the predetermined threshold pressure: continue with the start-up test sequence without controlling the pump to operate for the predetermined time period.

Description

TECHNICAL FIELD

[0001] The present invention relates to a mobile negative pressure wound therapy (NPWT) device, and to a method of testing such a NPWT device. BACKGROUND

[0002] Negative pressure wound therapy (NPWT) is a technique for promoting healing of e.g. surgical wounds, acute wounds and chronic wounds by applying negative pressure, i.e. below atmospheric pressure, to the wound using a negative pressure pump. The NPWT technique also enables the wound to be subjected to less external disturbance and provides a function for transporting excess liquid from the wound site. Generally, the NPWT technique has so far mainly been applied to patients in a hospital environment. However, recent product development has enabled patients to use the technique in a home environment.

[0003] In order to make it easier and more comfortable for a user to benefit from NPWT, mobile NPWT devices have recently been developed. In order for such a NPWT device to be truly mobile, it is in practice necessary to power the NPWT device with one or more batteries. Naturally, the operation of the NPWT device will eventually reduce the amount of energy stored in the battery (or batteries) so that it is necessary to replace the battery with a fully charged battery. After battery replacement, and at other times, it can be desirable to subject the NPWT device to a start-up test in order to reduce the risk of injury or discomfort to the user. SUMMARY

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

[0005] According to a first aspect of the application, there is thus provided a mobile negative pressure wound therapy (NPWT) device, the NPWT device comprising: an inlet fluidly connectable 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 a negative pressure in the canister; a pressure sensor arranged to sense a pressure in the canister; and a control circuit for controlling operation of the NPWT device. The control circuit is configured to: receive a start request for the NPWT device; in response to the start request, initiate a start-up test sequence of the NPWT device; acquire a first signal from the pressure sensor indicative of the pressure in the canister; evaluate the acquired first signal; when the acquired first signal is indicative of a pressure less negative than a predetermined threshold pressure: control the pump to run for a predetermined time period; acquire a second signal from the pressure sensor after the predetermined time period; continue with the start-up test sequence; and unless the NPWT device fails at least one test in the start-up test sequence by failing to meet at least one set of predetermined criteria, allow the NPWT device to transition to a therapy mode; and when the acquired signal is indicative of a pressure more negative than the predetermined threshold pressure: continue with the start-up test sequence without controlling the pump to run for the predetermined time period; and, unless the NPWT device fails at least one test in the start-up test sequence by failing to meet at least one set of predetermined criteria, allow the NPWT device to transition to the therapy mode.

[0006] It should be noted that the start-up test sequence can also comprise a decision to abort the start-up test sequence in case of failing a test. Thus, the step of continuing with the start-up test sequence can involve aborting the start-up test sequence.

[0007] It should also be noted that the pressure sensor need not be arranged to directly sense the pressure in the canister, but the pressure sensor can be arranged to sense the pressure at another location in the NPWT device at which the sensed pressure is indicative of the pressure in the canister. Furthermore, the pressure sensor can sense another property, e.g. a force or a deflection, based on which a change in pressure can be inferred.

[0008] The start request can be any indication that the NPWT device is desired to be prepared for therapy. For example, the start request can be a power on (insertion of one or more batteries), or a press of a start button, or a reset operation, etc.

[0009] When referring to a "pressure more negative than a predetermined threshold pressure", it should be understood that "negative" is in relation to atmospheric pressure, and that this corresponds to an absolute pressure below a predetermined absolute threshold pressure.

[0010] The present invention is based on the insight that during a start-up test, before the pump is run, there is a possible use case in which a negative pressure can exist in the NPWT system, and it is desirable to prevent the pump from running in such a case. It cannot be safely assumed that the caregiver or user always follows all the operating instructions of the NPWT system. For example, a possible and undesirable use case can be that before a battery is changed or a new NPWT device is switched to, a tube that is flowing to the chamber outlet at the wound site is blocked, and after the start-up test has been performed, it is unblocked after being connected to the inlet of the NPWT device. In this case, there will be a negative pressure in the canister of the NPWT device before the start-up test sequence is initiated. For this and other similar cases, the present inventor has found that it is desirable to avoid performing the regular test of the pressure sensor and the pump during the start-up test sequence, but to continue with the start-up test sequence based on the finding that the pressure is more negative than a predetermined threshold pressure. The predetermined threshold pressure can for example be atmospheric pressure, or in other words zero negative pressure. Alternatively, the predetermined threshold pressure can be a predetermined non-zero negative pressure.

[0011] Thus, after the start-up test and unblocking of the tube is completed, the risk of the start-up test causing discomfort or even injury to the user can be reduced.

[0012] Furthermore, at least for most use cases, if the signal obtained from the pressure sensor indicates a pressure that is more negative than the predetermined threshold pressure, it is an indication that the pressure sensor is working and that the pump has recently been run, and it can be concluded that it is less risky to allow the NPWT device to transition to the therapy mode than it is to run the pump for a predetermined period of time.

[0013] The predetermined time period can be at least 0.5 seconds, and can advantageously be closer to 1 second, for example approximately 0.9 seconds.

[0014] Advantageously, the first signal can be obtained from the pressure sensor before any running of the pump that is included in the start-up test sequence.

[0015] According to various embodiments, the control circuit can further be configured to, when the obtained first signal indicates a pressure that is less negative than the predetermined threshold pressure, evaluate a second signal obtained from the pressure sensor; and determine that the NPWT device has fulfilled a criterion of the predetermined set of criteria when the second signal indicates a negative pressure within a predetermined interval. For example, the control circuit can be configured to determine that the NPWT device has fulfilled the criterion when the second signal obtained from the pressure sensor indicates a pressure that is more negative (a lower absolute pressure) than the pressure indicated by the first signal obtained from the pressure sensor.

[0016] According to embodiments, the control circuit can further be configured to, when the obtained first signal indicates a pressure that is more negative than the predetermined threshold pressure, determine that the NPWT has fulfilled a criterion of the predetermined set of criteria without controlling the pump to run for a predetermined time period.

[0017] In embodiments, the control circuit can further be configured to, after the NPWT device has been allowed to switch to the therapy mode: repeatedly acquire signals from the pressure sensor while the pump is controlled to run; evaluate the signals acquired from the pressure sensor; and determine that the pressure sensor is not functioning in case the signals acquired from the pressure sensor are always at a minimum value that can be acquired from the pressure sensor, or the signals acquired from the pressure sensor are always at a maximum value that can be acquired from the pressure sensor, or the signals acquired from the pressure sensor alternate between the minimum value and the maximum value; or the signals acquired from the pressure sensor indicate an increasing pressure over time.

[0018] These embodiments cover two important failure modes that can indicate a non- functioning pressure sensor. In a first failure mode, the connection between the pump and the control circuit comprised in the NPWT device can be interrupted, and in a second failure mode, there can be a problem in the amplification circuitry involved in the pressure sensing. In case of an interrupted connection, it has been found that the interrupted electrical conductor connected to the control circuit can act as an antenna, and the signal acquired by the control circuit will be a minimum signal, e.g. 0 V, or a maximum signal, e.g. 3.3 V (or any other relevant maximum voltage in the NPWT device). As for a problem in the amplification circuitry, it has been found that this can result in a reversed pressure signal curve, which indicates an increasing absolute pressure, while in fact there is a decreasing absolute pressure (or a more negative pressure relative to atmospheric pressure).

[0019] Furthermore, according to various embodiments, the mobile NPWT device can additionally comprise a battery and a loudspeaker, and the control circuit can be further configured to: control the loudspeaker to run to emit a sound; measure a battery voltage drop during the loudspeaker is running; and determine that the NPWT device has fulfilled a criterion in a predetermined set of criteria when the battery voltage drop during the loudspeaker is running is less than a predetermined value.

[0020] According to a second aspect of the present invention, there is provided a method of testing a mobile negative pressure wound therapy (NPWT) device, the NPWT device having an inlet 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 a negative pressure in the canister, and a pressure sensor arranged to sense a pressure in the canister, the method comprising the steps of: receiving a request for activation of the NPWT device; in response to the request for activation, initiating an activation test comprising an activation test sequence for the NPWT device; obtaining a first signal from the pressure sensor indicative of the pressure in the canister; evaluating the first signal obtained from the pressure sensor; when the obtained first signal is indicative of a pressure that is less negative than a predetermined threshold pressure: controlling the pump to run for a predetermined time period; obtaining a second signal from the pressure sensor after the predetermined time period; continuing with the activation test sequence; and determining that the NPWT device passes the activation test unless the NPWT device fails at least one test in the activation test sequence due to failing to meet at least one of a predetermined set of criteria; and, when the obtained signal is indicative of a pressure that is more negative than the predetermined threshold pressure: continuing with the activation test sequence without controlling the pump to run for the predetermined time period; and, determining that the NPWT device passes the activation test unless the NPWT device fails at least one test in the activation test sequence due to failing to meet at least one of a predetermined set of criteria.

[0021] Variations and advantages of the second aspect of the invention are largely analogous to those described above in relation to the first aspect.

[0022] According to a third aspect of the present invention, there is provided a computer program comprising instructions for causing a control unit comprised in a NPWT device according to embodiments of the first aspect to perform the steps of the method according to embodiments of the second aspect when the computer program is run on the control unit.

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

[0024] The mobile NPWT device according to embodiments of the present invention can be comprised in a negative pressure wound therapy (NPWT) system further comprising a chamber for establishing a negative pressure, the chamber being arranged at a wound site, the chamber having an outlet, and a tube fluidly connecting the outlet of the chamber and the inlet of the NPWT device.

[0025] In summary, the present invention thus relates to a mobile negative pressure wound therapy (NPWT) device, the NPWT comprising an inlet 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 a negative pressure in the canister; a pressure sensor arranged to sense the pressure in the canister; and a control circuit for controlling the operation of the NPWT device. The control circuit is configured to: initiate a test sequence for the NPWT device; acquire a first signal indicative of the pressure in the canister; evaluate the first signal; when the acquired first signal is indicative of a pressure less negative than a predetermined threshold pressure: control the pump to operate for a predetermined time period; acquire a second signal after the predetermined time period; continue with the start-up test sequence; and when the acquired signal is indicative of a pressure more negative than the predetermined threshold pressure: continue with the start-up test sequence without controlling the pump to operate for the predetermined time period. BRIEF DESCRIPTION OF DRAWINGS

[0026] These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing example embodiments of the invention, wherein:

[0027] Figure 1 is a diagram of an exemplary mobile NPWT system according to an embodiment of the invention;

[0028] Figure 2 is a flow chart illustrating a first exemplary configuration of a mobile NPWT device according to an embodiment of the invention;

[0029] Figure 3 is a flow chart illustrating a second exemplary configuration of a mobile NPWT device according to an embodiment of the invention; and

[0030] Figure 4 is a flow chart illustrating a third exemplary configuration of a mobile NPWT device according to an embodiment of the invention. DETAILED DESCRIPTION

[0031] The present disclosure will now be described more fully with reference to the accompanying drawings, in which current preferred embodiments of the disclosure are shown. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of thorough and complete disclosure of the disclosure and completely convey the scope of the disclosure to those skilled in the art. Like reference numerals refer to like elements throughout.

[0032] Turning now to the drawings, and in particular Figure 1A negative pressure wound therapy (NPWT) system 1 is conceptually illustrated, comprising a portable NPWT device 3 according to an exemplary embodiment of the invention. The NPWT system 1 also includes a wound cover 5 having a chamber 6 disposed at the wound site. The wound cover 5 including the chamber 6 is adapted to form a sealed space 7, for example, at or around the user's skin or wound, the sealed space being partially defined by the wound surface 9. Figure 1 As schematically shown, chamber 6 has an inlet 8 and an outlet 10. The outlet 10 of chamber 6 is flowably connected to the mobile NPWT device 3 via a pipe 11, and the inlet 8 of chamber 6 passes through a filter (in... Figure 1 The tube 11 (not visible in the center) is connected to the surrounding environment (air around the user) to allow continuous air leakage into the chamber 6. The tube 11 can be any suitable flexible tube made of elastomer and / or polymer material.

[0033] like Figure 1 As schematically illustrated, the NPWT device 3 includes a negative pressure pump 13 adapted to establish a negative pressure when the pump 13 is controlled to operate. The negative pressure pump 13 can be any biocompatible type of pump and maintains or draws a sufficient and therapeutic vacuum level. Preferably, the negative pressure level to be achieved can be in the range of about -20 mmHg to about -300 mmHg. In possible embodiments of this disclosure, a negative pressure range of about -80 mmHg to about -140 mmHg can be used. In possible embodiments of the invention, the negative pressure pump 13 is a diaphragm type or a peristaltic type pump.

[0034] The negative pressure pump 13 is fluidly connected to the tank 15, which also forms part of the NPWT device 3. The tank 15 may be formed of, for example, molded plastic or the like, and may be a removable part of the NPWT device 3. Preferably, the tank 15 may be at least partially transparent / semi-transparent to allow observation of the interior of the tank 15, thereby helping the user determine the remaining capacity of the tank 15.

[0035] An inlet port 17 is formed at the tank 15 to allow connection to the tube 11. The inlet port 17 may also be formed elsewhere on the NPWT device 3, but still fluidly connected to the tank 15. The connection between the inlet port 17 and the tube 11 is a sealed connection, ensuring no leakage occurs at the inlet port 17 during normal operation of the NPWT device 3. Preferably, the tube 11 is releasably connected to the inlet port 17 by conventional components including friction fits, bayonet couplings, snap-fit ​​couplings, barbed connectors, or the like. The inlet port 17 may be made of the same material as the tank 15 and / or simultaneously molded / formed. A similar sealed connection (e.g., using a flange isolation element / “O-ring”) may be formed between the tank 15 and the negative pressure pump 13.

[0036] The NPWT device 3 also includes a battery 19 for supplying power to the NPWT device 3. The battery 19 may preferably be rechargeable, but may also be disposable. With respect to some embodiments of this disclosure, particularly suitable battery packs may be used.

[0037] The NPWT device 3 also includes a control unit 21 for controlling the operation of the mobile NPWT device 3, at least one pressure sensor 23 arranged to sense the pressure in the tank 15, and a speaker 24 for providing user feedback and / or alarms.

[0038] The control unit 21, powered by battery 19 and connected to pump 13, pressure sensor 23, and speaker 24, may include a microprocessor, microcontroller, programmable digital signal processor, or other programmable device. The control unit 21 may also, or alternatively, include an application-specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where the control unit 21 includes a programmable device such as a microprocessor, microcontroller, or programmable digital signal processor as described above, the processor may also include computer-executable code that controls the operation of the programmable device.

[0039] During use of the NPWT device 3, a wound dressing 5 is placed over the user's wound site, forming a sealed space 7. A tube 11 is configured to fluidly connect the outlet 10 of the chamber 6 in the wound dressing 5 to the inlet port 17 of the NPWT device 3. Then, to begin treatment, the portable NPWT device 3 can be initiated, for example, by the user pressing the start / pause button (in...). Figure 1 (Not shown in the image) to activate. In response to the request to begin treatment, control unit 21 can control the operation of negative pressure pump 13. When running, negative pressure pump 13 will begin to expel air through canister 15, inlet port 17, pipe 11, and the sealed space 7 formed by chamber 6 in wound dressing 5. Thus, negative pressure will be generated within sealed space 7. If fluid has already been generated at the wound site, fluid from the wound site can be at least partially "drawn" from the wound site through pipe 11, inlet port 17, and into canister 15 due to continuous limited leakage provided by inlet 8 of chamber 6. The amount of fluid (sometimes called exudate) drawn from the wound and collected in canister will depend on the type of wound being treated and the type of wound dressing used. For example, in the case of using absorbent dressing, fluid can be absorbed and collected in canister and wound dressing, while if a dressing with no or very low absorbency is used, most or all of the fluid from the wound site can be collected in canister. Suitable filter components (in the image) Figure 1 (Not shown) can be arranged between tank 15 and negative pressure pump 13 to ensure that no liquid can pass from tank 15 to negative pressure pump 13.

[0040] As mentioned above, the mobile NPWT device 3 requires a battery pack 19 to be charged for operation, and when the battery pack 19 is depleted, the battery pack needs to be replaced. After battery replacement, or if the NPWT device 3 is replaced by a new device, the NPWT device 3 is tested to reduce the risk of malfunctioning during subsequent treatment.

[0041] To this end, the control unit 21 in the NPWT device 3 according to embodiments of the present application can be configured to perform a test procedure according to embodiments of the present application. In particular, the processing circuit comprised in the control unit 21 can be programmed to perform the steps of various embodiments of the method according to the present application.

[0042] In the following, embodiments of the present application will be described with reference to flow charts in Figure 1 , in addition to the illustrations in Figure 2 , Figure 3 and Figure 4 .

[0043] Figure 2 is a flow chart illustrating a first exemplary configuration of a mobile NPWT device according to embodiments of the present application. With reference to Figure 2 , the control unit 21 of the NPWT device 3 can be configured to receive 100 a start request, which can be provided, for example, in the form of a predetermined operation of a button or a reset switch, or in the form of a power-up after replacement of the battery pack 19.

[0044] In response to the start request, the control unit 21 is configured to initiate 101 a start test sequence for the NPWT device 3.

[0045] As part of the start test sequence, the control unit 21 is configured to obtain 102 a first signal P1 from the pressure sensor 23 indicative of the pressure in the canister 15.

[0046] The control unit 21 is configured to evaluate 103 the first signal P1 obtained from the pressure sensor 23, and when the first signal P1 is indicative of a pressure that is less negative than a predetermined threshold pressure P 阈值 The control unit 21 is configured to control 104 the pump 13 to run during a predetermined time period T, and to obtain 105 a second signal P2 indicative of the pressure in the canister 15 after the predetermined time period T.

[0047] The control unit 21 is configured to evaluate 106 the second signal P2 obtained from the pressure sensor 23 after the predetermined time period T, and when the second signal P2 is indicative of the pressure not having become more negative, or not having become sufficiently more negative to provide an indication that the pump 13 is running as desired, the control unit 21 can be configured to determine 107 that the NPWT device 3 has failed the start test.

[0048] On the other hand, when the second signal P2 indicates that the pressure in the canister 15 has become more negative than (or sufficiently more negative than) the pressure indicated by the first signal P1, the control unit 21 is configured to proceed 108 with initiating the test sequence and determine 109 whether the NPWT device 3 fails 110 the initiation test or passes the initiation test. If the initiation test is determined by the control unit 21 to have been passed by the NPWT device 3, the control unit 21 can be configured to allow 111 the NPWT device 3 to transition to the therapy mode.

[0049] When the NPWT device 3 has been allowed to transition to the therapy mode, the control unit 21 can be configured to directly transition the NPWT device 3 to the therapy mode, or to transition the NPWT device to the therapy mode in response to a user request, such as a predetermined operation of a user interface, such as a button or a touch screen. The predetermined time period T can advantageously be at least 500 ms to ensure a reliable indication of the operability of the pump 13 and / or the pressure sensor 23, regardless of the configuration of the NPWT system 1. Even more advantageously, the predetermined time period can be at least 700 ms, such as 900 ms.

[0050] After the control unit 21 has allowed the NPWT device 3 to transition to the therapy mode, or as part of the initiation test sequence, the control unit 21 can be configured to take additional steps to test the operability of the pump 13 and / or the pressure sensor 23 of the NPWT device 3. In particular, the control unit 21 can be configured to determine 213 whether the pump 13 is able to generate a pressure in the canister 15 that is higher than a predetermined threshold pressure Pth, and / or to determine 214 whether the pressure sensor 23 is able to detect a pressure in the canister 15 that is lower than a predetermined threshold pressure Pth. Figure 3 A second exemplary configuration of a mobile NPWT device according to an embodiment of the present application is schematically illustrated in Fig. 2. Reference is made to the description of Fig. 1 for the components of the NPWT device 3. Figure 3 The control unit 21 of the NPWT device 3 can thus additionally be configured to control 200 the pump 13 to operate, and repeatedly acquire 201 the signal P(t) from the pressure sensor 23 while the pump 13 is operating.

[0051] During or after acquiring the signal P(t) from the pressure sensor 23, the control unit 21 can be configured to evaluate the signal P(t) from the pressure sensor 23 to determine whether at least one of two failure modes can be identified. When it is determined 202 that the signal P(t) acquired from the pressure sensor 23 is always at a minimum value P 最小 that can be acquired from the pressure sensor 23, or that the signal P(t) acquired from the pressure sensor 23 is always at a maximum value P 最大 that can be acquired from the pressure sensor 23, or that the signal P(t) acquired from the pressure sensor 23 is between a minimum value P 最小 and a maximum value P 最大alternating between, the control unit 21 can be configured to identify a first fault pattern indicative of a disconnection between the control unit 21 and the pressure sensor 23. When it is determined 203 that the signal P(t) acquired from the pressure sensor 23 is indicative of an increasing pressure over time, the control unit 21 can be configured to identify a second fault pattern indicative of a failure in the amplification circuit in the pressure sensor 23.

[0052] When any of these fault patterns is identified by the control unit 21, the control unit is configured to determine 204 that the signal P(t) from the pressure sensor 23 is unreliable, and that the pressure sensor 23 should therefore be classified as faulty. In this case, the control unit 21 can be configured to take action by preventing the NPWT 3 from entering the therapy mode or interrupting the therapy. The control unit 21 can also be configured to provide an indication to the user via the user interface.

[0053] When none of these fault patterns is identified by the control unit 21, the control unit is configured to determine 205 that the pressure sensor 23 is working as intended, and that the NPWT 3 can be allowed to enter or continue in the therapy mode.

[0054] As part of the start-up test sequence, the control unit 21 can be configured to take additional steps to test the operation of the NPWT device 3. Figure 4 This third exemplary configuration of the mobile NPWT device 3 according to an embodiment of the present application is schematically illustrated. Referring to Figure 4 The control unit 21 of the NPWT device 3 can thus additionally be configured to control 300 the loudspeaker 24 to emit a sound. Since the loudspeaker 24 is one of the most power-consuming components of the NPWT device 3, this can be an effective way of assessing the health of the battery pack 19. According to the instructions, a depleted battery pack 19 should be replaced by a fully charged or new battery pack 19. However, if the instructions are not followed, a depleted battery pack 19 can be replaced by another at least partially depleted battery pack 19.

[0055] The control unit 21 can thus be configured to measure 301 the battery voltage drop AV resulting from the operation of the loudspeaker 24.

[0056] The control unit 21 can be configured to compare 302 the measured battery voltage drop AV to a predetermined threshold voltage drop AV 阈值 The measured battery voltage drop AV is assessed 302, and when the battery voltage drop during loudspeaker operation is less than the predetermined threshold voltage drop AV 阈值 the control unit 21 determines 303 that the NPWT device has fulfilled a criterion in the predetermined set of criteria, enabling the start-up test sequence to proceed.

[0057] Conversely, when the control unit 21 determines that the measured battery voltage drop AV is greater than the predetermined threshold voltage drop AV 阈值At 304, the control unit 21 can be configured to determine that the NPWT device 3 has failed the start-up test.

[0058] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. The mere 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.

Claims

1. A portable negative pressure wound therapy (NPWT) device, the NPWT device comprising: An inlet, which is fluidly connected to the wound site; A canister, which is fluidly connected to the inlet for collecting fluid from the wound site; A pump, which is fluidly connected to the tank to establish a negative pressure in the tank; A pressure sensor, arranged to sense the pressure in the tank; and A control circuit for controlling the operation of the NPWT device, the control circuit being configured to: Receive the start request from the NPWT device; In response to the startup request, initiate the startup test sequence of the NPWT device; A first signal indicating the pressure in the tank is obtained from the pressure sensor; Evaluate the first signal acquired from the pressure sensor; When the acquired first signal indicates a pressure that is less negative than the predetermined threshold pressure: Control the pump to operate within a predetermined time period; A second signal is acquired from the pressure sensor after the predetermined time period; Continue with the aforementioned startup test sequence; as well as Unless the NPWT device fails at least one test in the initiation test sequence due to failure to meet at least one criterion in the predetermined set of criteria, the NPWT device is allowed to switch to treatment mode; and When the acquired first signal indicates a pressure more negative than the predetermined threshold pressure: Continue with the startup test sequence without controlling the pump to operate during the predetermined time period; and Unless the NPWT device fails to pass at least one test in the activation test sequence due to failure to meet at least one criterion in the predetermined set of criteria, the NPWT device is allowed to switch to treatment mode.

2. The NPWT device according to claim 1, wherein, When the acquired first signal indicates a pressure less negative than the predetermined threshold pressure, the control unit is further configured to: Evaluate the second signal acquired from the pressure sensor; and When the second signal indicates negative pressure within a predetermined interval, it is determined that the NPWT device has met the criteria in the predetermined set of criteria.

3. The NPWT device according to claim 1 or 2, wherein, When the acquired first signal indicates a pressure more negative than the predetermined threshold pressure, the control unit is further configured to: Determine that the NPWT has met the criteria in the predetermined set of criteria, without controlling the pump to operate during the predetermined time period.

4. The NPWT device according to claim 1 or 2, wherein, The control unit is also configured to, after the NPWT device has been permitted to switch to treatment mode: Signals are repeatedly acquired from the pressure sensor; Evaluate the signal acquired from the pressure sensor; and The pressure sensor is determined to be malfunctioning under the following conditions: The signal obtained from the pressure sensor is always at the minimum value that can be obtained from the pressure sensor, or the signal obtained from the pressure sensor is always at the maximum value that can be obtained from the pressure sensor, or the signal obtained from the pressure sensor alternates between the minimum value and the maximum value; or The signal obtained from the pressure sensor indicates that the pressure increases over time when the pump is running.

5. The NPWT device according to claim 1 or 2, wherein, The NPWT device also includes a battery and a speaker, and the control circuit is further configured to: Control the speaker to operate and emit sound; The battery voltage drop was measured during the operation of the speaker. as well as When the battery voltage drop is less than a predetermined value during speaker operation, it is determined that the NPWT device has met the criteria in the predetermined set of criteria.

6. A computer program product, the computer program product comprising instructions for causing a control unit included in a mobile negative pressure wound therapy (NPWT) device to perform the following steps: Receive the start request from the NPWT device; In response to the startup request, a startup test including a startup test sequence for the NPWT device is initiated; A first signal indicating the pressure in a canister is obtained from a pressure sensor included in the NPWT device, the canister being included in the NPWT device and fluidly connected to an inlet of the NPWT device for collecting fluid from a wound site, the inlet being fluidly connected to the wound site; Evaluate the first signal acquired from the pressure sensor; When the acquired first signal indicates a pressure that is less negative than the predetermined threshold pressure: The pump is controlled to operate within a predetermined time period. The pump is included in the NPWT device and fluidly connected to the tank for establishing negative pressure in the tank. A second signal is acquired from the pressure sensor after the predetermined time period; Continue with the aforementioned startup test sequence; as well as Unless the NPWT device fails at least one test in the startup test sequence due to failure to meet at least one criterion in the predetermined set of criteria, the NPWT device is determined to have passed the startup test; and When the acquired first signal indicates a pressure more negative than the predetermined threshold pressure: Continue the startup test sequence without controlling the pump to operate during the predetermined time period; and Unless the NPWT device fails to pass at least one test in the startup test sequence due to failure to meet at least one criterion in the predetermined set of criteria, the NPWT device is determined to have passed the startup test.

7. The computer program product of claim 6, wherein the computer program product further comprises instructions for causing the control unit to perform the following steps: Evaluate the second signal acquired from the pressure sensor; and When the second signal indicates negative pressure within a predetermined interval, it is determined that the NPWT device has met the criteria in the predetermined set of criteria.

8. The computer program product according to claim 6 or 7, wherein, When the acquired first signal indicates a pressure more negative than the predetermined threshold pressure, the computer program product further includes instructions for causing the control unit to perform the following steps: Determine that the NPWT has met the criteria in the predetermined set of criteria, without controlling the pump to operate during the predetermined time period.

9. The computer program product according to claim 6 or 7, wherein, The computer program product also includes the following steps for causing the control unit to perform after it has been determined that the NPWT device has passed the startup test: Signals are repeatedly acquired from the pressure sensor; Evaluate the signal acquired from the pressure sensor; and The pressure sensor is determined to be malfunctioning under the following conditions: The signal obtained from the pressure sensor is always at the minimum value that can be obtained from the pressure sensor, or the signal obtained from the pressure sensor is always at the maximum value that can be obtained from the pressure sensor, or the signal obtained from the pressure sensor alternates between the minimum value and the maximum value; or The signal obtained from the pressure sensor indicates that the pressure increases over time when the pump is running.

10. A negative pressure wound therapy (NPWT) system, wherein the NPWT system comprises: A chamber for creating negative pressure is arranged at the wound site, and the chamber has an outlet; The NPWT device according to claim 1 or 2; and A pipe that fluidly connects the outlet of the chamber to the inlet of the NPWT device.

11. The NPWT system according to claim 10, wherein, The chamber also has an inlet that is connected to the surrounding environment via a filter, allowing air to continuously leak into the chamber.

Images