GB2612313A

GB2612313A - Intermittent pneumatic compression device

Info

Publication number: GB2612313A
Application number: GB2115404.2A
Authority: GB
Inventors: green Ivan; Ingram Stephen
Original assignee: Ig Tech Ltd
Current assignee: Ig Tech Ltd
Priority date: 2021-10-26
Filing date: 2021-10-26
Publication date: 2023-05-03
Anticipated expiration: 2041-10-26
Also published as: WO2023073342A1; GB2612313B; GB202115404D0

Abstract

An intermittent pressure compression (IPC) device 2, for the treatment of Venous Thromboembolism (VTE), including; a sleeve 4 configured to surround a limb of a patient; a bladder 6 attached to the sleeve; and a pumping device 8 configured to inflate and deflate the bladder to apply pressure to the limb of the patient. The pumping device includes a piezoelectric pump. There is also provided a system including a plurality of the IPC devices and a method of operating the system. The device may have a rechargeable battery (26, fig.2) and the pumping device may comprise a processor (28, fig.2) configured to receive signals form an input to control the piezoelectric pump.

Description

INTERMITTENT PNEUMATIC COMPRESSION DEVICE TECHNICAL FIELD

The present disclosure relates generally to a device for treatment of Venous Thromboembolism (VTE) and more specifically to an intermittent pneumatic compression (IPC) device.

BACKGROUND

VTE is a condition in which a blood clot (or a thrombus) forms in a vein, most commonly in the deep veins of the legs or pelvis. This is known as Deep Vein Thrombosis (DVT). The blood clot can dislodge and travel in the bloodstream to other parts of the body, such as the pulmonary arteries (which is known as pulmonary embolism) when a blood vessel in the lungs is blocked by the blood clot. VTE includes both DVT and pulmonary embolism.

DVT can occur in the lower limbs due to blood flowing slowly or pooling in the veins in these regions. Intermittent pneumatic compression (IPC) of these limbs (i.e., the legs) has been used to reduce venous stasis (or haemostasis), and may achieve this reduction by increasing the velocity of venous return of the blood. The pressure typically applied by IPC is about 40-50 mmHg (5.3-6.7 kPA). This pressure may be applied either sequentially or discretely to the calf or thigh muscles to provide artificial pumping of the blood through the veins. IPC is often used following surgery when a patient is immobile, or when the patient cannot move a particular limb.

Conventional IPC devices have included a sleeve to be placed round the patient's limb, e.g., leg, and attached to a large pump, which is often used to power multiple devices. The pump has been connected to mains power. Other devices have used DC pump which attaches to a sleeve to be placed round the patient's limb. The DC pumps needs to be recharged regularly, such as more than once a day. The pumps typically operate at over 70 dB and can weigh over 250g.

It is desired to provide an improved IPC device, in particular to provide a light, quiet device that does not require charging so regularly as the previously known devices and is more comfortable for the patient. The device also provides connectivity to allow the device or devices to be monitored remotely by the patient or carer.

SUMMARY

In accordance with the invention, there is provided an intermittent pressure compression (IPC) device including a sleeve, a bladder and a pumping device. The sleeve is configured to surround a limb of a patient. The bladder is attached to the sleeve. The pumping device is configured to inflate and deflate the bladder to apply pressure to the limb of the patient. The pumping device includes a piezoelectric pump. Using a pumping device in this manner (with a piezoelectric pump combined and integrated into a sleeve) provides an IPC device that is easy to use, produces little or no noise, is light, and low powered.

The pumping device may be configured to apply a pressure of 10-135 mmHg (1.3 -18.0 kPa) above atmospheric pressure to the limb of the patient.

The IPC device may include a rechargeable battery.

The sleeve may have a surface area configured to contact the patient's skin. The pumping device may overlie the sleeve and be sized such that the pumping device occupies less than about 30% of the surface area as it overlies the sleeve.

The pumping device may include a processor configured to receive signals from an input and to control the piezoelectric pump.

The input to the processor may be a wireless input.

The processor may be configured to detect ambulation of the patient.

The ambulation of the patient may be detected by monitoring of a rise time of a set pressure applied by the pumping device to the bladder.

In accordance with the invention, there is also provided a system including a plurality of any of the above IPC devices and a central controller. The central controller is configured to receive data from and provide control to the IPC devices.

The system may include wireless connections between the central controller and the plurality of IPC devices.

In accordance with the invention, there is also provided a method of operating the above system. The method includes placing the plurality of the IPC devices respectively on a plurality of patients' limbs; monitoring outputs from each of the plurality of IPC devices to determine a state of each patient; in response to the state of each patient, selecting a mode of operation for each respective IPC device; and sending a signal to each IPC device to pump the bladder in the selected mode of operation for the respective device.

The method may include, after sending the signal to each IPC device to pump the bladder in the selected mode of operation, recording the response of each respective device and providing feedback to a user.

The state of each patient determined may include: an ambulation state, wherein the patient is ambulatory; and a stationary state, wherein the patient is stationary.

The outputs from the plurality of IPC devices may include a rise time of a set pressure at a constant power input to the piezoelectric pump. The method may include selecting a threshold time such that when the rise time is below the threshold time, the patient is in the stationary state, and when the rise time is above the threshold time, the patient is in the ambulation state.

The state of each patient determined may also include a sleeve failure state, wherein the sleeve is not correctly attached to the patient's limb. In response to detection of the sleeve failure state a signal may be provided to a or the user to reapply the IPC device correctly.

The modes of operation may include a first and a second mode of operation. The first mode of operation may include applying a cyclical pressure to the limb of the patient around which the IPC device is located. The cyclical pressure may include repeatedly applying an increased pressure of about 15-60 mmHg (2.0-8.0 kPa) above standard atmospheric pressure for a first period of time between 5 and 15 seconds, and then returning the pressure close to atmospheric pressure for a second period of time between 20 and 40 seconds. The second mode of operation may include maintaining a static, increased pressure of about 15-30 mmHg (2.0-4.0 kPa) above atmospheric pressure to the limb of the patient.

BRIEF DESCRIPTION OF DRAWINGS

Various embodiments will now be described, by way of example only, and with reference to the accompanying drawings in which: Fig. 1 shows an exemplary IPC device in accordance with the invention; Fig. 2 shows the pump of the IPC device of Fig. 1; Fig. 3 shows an electronics structure diagram of a piezo electric pump of the invention; Fig. 4 is a block diagram showing the arrangement of multiple IPC devices in a centrally controlled system; and Fig.5 shows a typical pressure-time plot of the device. DETAILED DESCRIPTION Figure 1 shows a device 2 configured to perform intermittent pneumatic compression of a person's limb (hereinafter "the IPC device"). Since the person will typically be a patient, the latter term will be used herein, but they may be interchanged. The IPC device 2 includes a sleeve 4 that forms substantially the outer surface of the device 2, as well as a bladder (or balloon) 6 and a pumping device 8.

The sleeve 4 is configured to wrap around a limb of a patient (e.g., an arm or a leg). The sleeve 4 may be placed around a calf or a thigh or around a foot. Although the sleeve 4 as shown would be configured to wrap around only one part of the patient's limb, the reader will appreciate that a sleeve 4 could be configured slightly differently to wrap around both a calf and thigh together, for example. The sleeve 4 is configured so that it can be secured to itself as it is wrapped around the limb of the patient. In the illustrated example the securing means includes three tongues 10 on one side of the sleeve 4 and a landing strip 12 on the other side, wherein the tongues 10 and strip 12 together include a hook and loop fastening system. The hooks may be associated with the tongues 10 and the loops associated with the strip 12 or vice versa. It will be appreciated that alternative securing means could be used, for example buttons, snap studs, magnetic snap fasteners, or buckles. This allows for variations in the patients anatomy to be catered for without the use of a large number of products. Alternatively the sleeve 4 could be a tubular elastomeric sleeve that wraps around the limb in the manner of a sock.

The sleeve 4 may be made of fabric material such as a combination of nylon and polyester, or other materials that are able to provide some compression to the limb of the patient, by resilience of the material(s). These materials also provide a level of comfort to the patient when wearing the sleeve 4 for extended periods.

When in use, the sleeve 4 may at least partially surround the limb of the patient to the extent required to perform IPC, depending on the securing means employed (normally of course the sleeve 4 would extend fully around the limb).

The bladder 6 is attached to the sleeve 4 along a substantial portion 14, e.g., about 80%, of the length L of the sleeve 4 and along a smaller portion 16, e.g., about 20% of the width W of the sleeve 4. The bladder 6 may be attached to the sleeve 4 at different size portions of the sleeve 4. The bladder 6 may be about 300 mm in length by about 150 mm in width. This is typically suitable when the IPC device 2 is to be used around a calf of the patient. Alternatively, the bladder 6 may be about 450 mm in length by about 180 mm in width. This is typically suitable when the IPC device 2 is to be used around a thigh of the patient. Alternative sizes of the bladder 6 may be used. For example, the length of the bladder 6 may be in the range of 200 mm to 500 mm, and the width of the bladder 6 may be in the range of 100 mm to 300 mm. The bladder 6 may be tapered and/or segmented to provide differential pressure starting distally towards the ankle and increasing proximally towards the knee.

The attachment of the bladder 6 to the sleeve 4 may be a removable attachment, such that bladders 4 may be replaced or interchanged. For example, the bladder 6 may be held in a pocket of the sleeve 4.

The pumping device 8 may be located adjacent to the bladder 6, which may be inflated by the pumping device 8 to apply pressure to the limb inside the sleeve 4 when the IPC device 2 is in use. The bladder 6 may be deflated to relieve pressure from the limb inside the sleeve 4. The degree of inflation of the bladder 6 provides varying degrees of pressure to the limb.

The length of the pumping device 8 may be in the range of 40 mm to 150 mm and at the same time the width of the pumping device 8 may be in the range of 20 mm to 60 mm. Additionally (or generally) the thickness of the pumping device 8 may be between 5 mm and 25 mm, or more narrowly the thickness of the pumping device 8 may be between 10 and 20 mm, for example, 15 mm.

The pumping device 8 is shown in more detail in Figure 2. The pumping device 8 includes a piezoelectric pump 18 (or a piezoelectric micropump) of a type such as the Disc pump TM of TTP Ventus TM. The piezoelectric pump 18 drives a diaphragm to generate a pressure. The pressure applied may be between 10 and 135 mmHg (1.3 and 18 kPa) above atmospheric pressure. The illustrated pumping device 8 also includes an inlet 20 configured to draw in air from outside the pumping device 8 and an outlet 22 connected to the bladder 6 (not shown in Figure 2) configured to drive the air into the bladder 6. The inlet 20 may include a grille in a casing of the pumping device 8. While the described IPC device 2 uses ambient air, alternative arrangements using an alternative fluid may be used. For example, a reservoir may be included in fluid communication with the pumping device 8. Liquids may be pumped to and from the reservoir to the bladder 6. Alternatively, fluid (air or liquid) may be pumped to and from different compartments attached to the sleeve 4 to apply and relieve pressure respectively. This may help with exhaustion.

The use of the pumping device 8 with a piezoelectric pump 18, combined and integrated into a simple sleeve as described herein, provides an IPC device 2 that is easy to use, produces little or no noise, is light, and low powered.

The pumping device 8 may operate in a number of modes of operation. In a first mode of operation, a cyclical pressure may be applied to the limb to simulate ambulation of the patient. The cyclical pressure includes applying an increased pressure (e.g., of about 40-60 mmHg (5.3-8.0 kPa) above standard atmospheric pressure) for a first period of time Ti, and then returning the pressure close to atmospheric pressure for a second period of time T2. The first period of time On which the increased pressure is applied) may be between 5 and 15 seconds. The second period of time (for the pressure to be relieved) may be slower, typically between about 20 and 40 seconds. The pressure may be applied and then relieved repeatedly, so as to provide a cyclical application of pressure. While the pressure is released the blood is able to flow into the veins of the limb of the patient. It will be appreciated that alternative pressures and frequency of pulses may be used. An exemplary cyclical pressure P is illustrated in Figure 5.

Cyclical pressure is typically used when the patient is stationary or immobile in order to assist the blood flow through the veins in the limb of the patient.

In a second mode of operation, the pumping device 8 may be used to maintain a static, increased pressure (e.g., of about 15-30 mmHg (2.0-4.0 kPa) above atmospheric pressure). It will be appreciated that alternative pressures may be used. The sleeve 4 itself may also contribute to the pressure applied to the limb of the patient, for example by the resilience of the material(s) of the sleeve 4.

The second mode of operation, with static application of pressure may typically be used when the patient is mobile (or ambulatory). The movement of the patient assists in contracting the vein to cause venous return of the blood. The static pressure reduces the cross-sectional area of the vein and so assists the muscle (for example the soleus muscle when the device is placed round the calf) in driving venous return. The device described herein is particularly useful for such applications since it is lightweight and can be used by a patient that is mobile. This is in contrast to conventional devices that are typically attached to the end of a bed (due to the large pump).

The pressure in either mode of operation may be graduated along the muscle of the limb of the patient, for example by applying pressure distally initially (e.g., near the ankle) and then increasingly proximally (e.g., toward the knee). In order to apply such a graduated pressure, the bladder 6 may include segments 6A, 6B, 6C, 60, 6E to which differential pressures may be applied. 5 segments have been illustrated in figure 1, with each segment 6A-E extending the width 16 of the bladder 6. A different number and arrangement of segments 6A-E would be possible, depending on the desired pressure application. VVhere segments 6A-E are used, different outputs of the pumping device 8 may be used for each segment 6A-E, or valves may be used between the segments 6A-E. Alternatively the pressure may be applied at the same pressure across the whole device. The location of the outlet of the pump into the bladder 6 can be used to cause the graduated or equal pressure.

The illustrated pumping device 8 also includes a battery 26 to power the piezoelectric pump 18 and a processor 28. The battery 26 may be a rechargeable battery. The battery 26 may hold enough charge to power the IPC device 2 for over 24 hours, and, more specifically, for some arrangements, over 48 hours. The battery 26 may be replaceable and/or may be chargeable via a USB connection 30 or a similar connection. Alternatively, the battery may be rechargeable via a wireless connection, such as inductive charging. The processor 28 controls the piezoelectric pump 18 to inflate or deflate the bladder 6 at certain speeds and frequencies and to certain pressures depending on a desired application. The processor 28 may include sensors 32 and/or transducers to monitor the pressure applied in response to which the processor 28 may select certain modes of operation as described above.

The processor 28 may be used to change between the operation modes by manual control, or automatic control based on the input received by sensors 32.

Automatic control may be determined based on the rise time of a set pressure at a constant power input to the piezoelectric pump 18. When the patient is ambulatory, the rise time at the constant power input is shorter than when the patient is stationary because the movement of the patient assists in contracting the muscles in the patient's limb. As such, when the rise time to the set pressure is below a set time, the IPC device 2 may be moved into the second operation mode.

Alternatively, different parameters may be used to monitor the same effects, for example, the power load of the piezoelectric pump 18 to reach a set pressure could be monitored. Gyroscopes and/or accelerometers may be used as an alternative, or additional means to monitor the ambulation of the patient.

Instead of automatically changing the operation mode of the IPC device 2, the IPC device 2 could provide a signal, such as a visual, or an audio signal (for example from a buzzer 34) to the user to indicate that the mode of operation could be changed.

The automatic control can also indicate, by monitoring the rise time of the set pressure, when the IPC device 2 is not attached correctly to the patient's limb. This may occur due to failure of the securing means 10, 12 that attaches the sleeve 4 to the patient's limb, for example. The IPC device 2 may provide a signal in this case to the user to reapply the IPC device 2 correctly.

Automatic control can reduce both the possibility for human error introduced to the care process, and also the amount of time required of medical professionals to monitor individual IPC devices 2.

Manual control may be used to change the operation mode of the I PC device 2 either in addition to, or instead of the automatic control. A user input may be used by a user to provide the manual control. The user input may be a touch electrode 36 connected to a capacitive touch controller 38. Alternatively wireless manual control may be used.

Figure 4 illustrates an aspect of the invention that is seen as inventive in its own right, albeit made possible by the use of a lightweight and portable IPC device (for example, as described above).

A system 50 is shown that includes a plurality of distributed IPC devices 2A, 2B, 20, 2D, 2E. The system 50 further comprises a central controller 40 configured to control and communicate with the various IPC devices 2A-E.

Some of the IPC devices (e.g. 2A, 2B and 2C) may be located in the same care facility as the central controller 40, for example in the same hospital 42 (or hospital ward, etc.). Others of the IPC devices (e.g. 2D and 2E) may be located in a different geographic area or separate facility as the central controller 40, such as at a patient's home (indicated at 44D and 44E).

The circuitry (e.g. processors 28) of the IPC devices 2A-E may be configured to communicate with the central controller 40 by a wired or wireless communication link.

Those IPC devices 2A, 2B, 20 in the vicinity of the central controller 40 may be connected by respective wireless connections 46B, 460 or by a wired connection 48A to a central controller 40. The wired connection 48A may be used in respect of a patient that is immobile, whereas the wireless connections 46B and 460 could be used in respect of a patient that is mobile (e.g., walking around a hospital ward). The ability to communicate with the central controller 40 whilst a patient is moving is seen as a particularly advantageous aspect of the IPC devices described herein, as well as the system 50 generally.

The circuitry (e.g. processors 28) of the IPC devices 2D, 2E may be connected to the central controller 40 by respective wireless connections 46D, 46E (e.g., the internet).

The wireless connections generally may be either local or wide area connections, such as over an intranet or the internet respectively. Short range connections, such as via BluetoothTM or RFID could be used as well.

The central controller 40 may be configured to communicate with multiple IPC devices 2A-E in a variety of different settings with different connections to the central controller 40 at the same time. The central controller 40 could be configured to monitor each IPC device 2A-E and gather and record information therefrom. This may be useful for any care provision, and could be carried out in a hospital or home care setting. The controller 40 may provide a visual guide to a user or operator (such as a carer) by, for example, showing the waveform of the pressure applied by the pumping device. The controller 40 may be used to remotely control the IPC devices 2A-E and/or warn the user or operator of malfunction, misuse, or lack of use of one or more IPC devices 2A-E. As will be appreciated, the exemplary system 50 shown in Figure 4 is one example of an arrangement of IPC devices with a central controller and other arrangements, such as with all the IPC devices in the vicinity of the central controller are envisaged. The use of IPC devices with a piezoelectric pump is particularly useful for these systems with multiple IPC devices because the piezoelectric pump is smaller, lighter and requires less power than the pumps of previous devices.

Although the present invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as set forth in the accompanying claims.

Claims

CLAIMS1. An intermittent pressure compression (IPC) device comprising: a sleeve configured to surround a limb of a patient; a bladder attached to the sleeve; and a pumping device configured to inflate and deflate the bladder to apply pressure to the limb of the patient, wherein the pumping device includes a piezoelectric pump.
2. The IPC device of claim 1, wherein the pumping device is configured to apply a pressure of 10-135 mmHg (1.3 -18 0 kPa) above atmospheric pressure to the limb of the patient.
3. The IPC device of claim 2, wherein the pumping device is configured to apply a pressure of 15 -60 mmHg (2.0-8.0 kPa) above atmospheric pressure to the limb of the patient.
The IPC device of any preceding claim, comprising a rechargeable battery.
5. The IPC device of any preceding claim, wherein the sleeve has a surface area configured to contact the patient's skin, and the pumping device overlies the sleeve and is sized such that the pumping device occupies less than about 30% of the surface area as it overlies the sleeve
6. The IPC device of any preceding claim, wherein the pumping device comprises a processor configured to receive signals from an input and to control the piezoelectric pump.
7. The IPC device of claim 6, wherein the input to the processor is a wireless input.
8. The IPC device of claim 6 or 7, wherein the processor is configured to detect ambulation of the patient.
9. The IPC device of claim 8, wherein the ambulation of the patient is detected by monitoring of a rise time of a set pressure applied by the pumping device to the bladder.
10. A system comprising: a plurality of IPC devices of any of claims 6 to 9; and a central controller, wherein the central controller is configured to receive data from and provide control to the IPC devices.
11. The system of claim 10, comprising wireless connections between the central controller and the plurality of IPC devices.
12. A method of operating the system of claim 10 or 11, wherein the method comprises: placing the plurality of the IPC devices respectively on a plurality of patients' limbs; monitoring outputs from each of the plurality of IPC devices to determine a state of each patient; in response to the state of each patient, selecting a mode of operation for each respective IPC device; and sending a signal to each IPC device to pump the bladder in the selected mode of operation for the respective device.
13. The method of claim 12, wherein the method further comprises, after sending the signal to each IPC device to pump the bladder in the selected mode of operation, recording the response of each respective device and providing feedback to a user.
14. The method of claim 12 or 13, wherein the state of each patient determined includes: an ambulation state, wherein the patient is ambulatory; and a stationary state, wherein the patient is stationary.
15. The method of claim 14, wherein the outputs from the plurality of IPC devices include a rise time of a set pressure at a constant power input to the piezoelectric pump, wherein the method includes selecting a threshold time such that when the rise time is below the threshold time, the patient is in the stationary state, and when the rise time is above the threshold time, the patient is in the ambulation state.
16. The method of claim 14 or 15, wherein the state of each patient determined also includes a sleeve failure state, wherein the sleeve is not correctly attached to the patient's limb, wherein, in response to detection of the sleeve failure state a signal is provided to a or the user to reapply the IPC device correctly.
17. The method of any of claims 12 to 16, wherein the modes of operation include a first and a second mode of operation, wherein the first mode of operation includes applying a cyclical pressure to the limb of the patient around which the IPC device is located, wherein the cyclical pressure includes repeatedly applying an increased pressure of about 15-60 mmHg (2.0-8.0 kPa) above standard atmospheric pressure for a first period of time between Sand 15 seconds, and then returning the pressure close to atmospheric pressure for a second period of time between 20 and 40 seconds, wherein the second mode of operation includes maintaining a static, increased pressure of about 15-30 mmHg (2.0-4.0 kPa) above atmospheric pressure to the limb of the patient.