WO2024089442A1

WO2024089442A1 - Apparatus and method for inducing vasoconstriction through localised cooling

Info

Publication number: WO2024089442A1
Application number: PCT/GB2023/052828
Authority: WO
Inventors: Sabrina RAMNARINE; Andrew Coleman; Christopher BUNTON; Benedict NEWMAN; Silke HEYSE; Gabriella SPINELLI
Original assignee: Guy's And St Thomas' Nhs Foundation Trust
Priority date: 2022-10-28
Filing date: 2023-10-30
Publication date: 2024-05-02
Also published as: GB202215969D0

Abstract

An apparatus and system configured to induce vasoconstriction through localised cooling, the apparatus comprising: at least one securing element for attaching the apparatus to a user's hand and/or foot; one or more cold air conduits; a plurality of apertures for egress of cold air; and one or more retaining structures configured to retain at least one of the one or more cold air conduits and to position the cold air conduit such that the one or more apertures are directed at the user's digits.

Description

Apparatus and Method for Inducing Vasoconstriction through Localised Cooling

Field of the Invention

The present invention relates to a wearable apparatus configured to provide localised cooling to the digits of a user, to achieve targeted vasoconstriction.

Background

Chemotherapy-induced peripheral neuropathy (CIPN), or damage to the peripheral nervous system is a challenging side effect of cancer treatment with significant sequalae. Affecting between 40% to 90% of patients receiving neurotoxic chemotherapy, CIPN is a major dose-limiting toxicity and can result in reduction, early cessation or change in chemotherapy which may have implications for prognosis and survival. While clinical presentation is predominantly sensory with patients experiencing numbness (paraesthesia), tingling (dysesthesia) and pain in their hands and feet (“glove and stocking distribution”), symptoms can also include motor and autonomic dysfunction. Long term complications such as difficult to treat chronic pain, functional impairment, permanent symptoms, and disability in approximately 40% of cancer survivors negatively impacts quality of life. CIPN is a cumulative effect as the toxicity levels increase with each chemotherapy treatment.

Gaps exist in the care pathway as there are no effective pharmacological strategies for prevention or mitigation of CIPN. This is of concern considering the incidence of cancer is increasing. Prevention of CIPN is therefore an urgent unmet clinical need.

Regional hypothermia or cooling of the skin has demonstrated encouraging results in supportive oncology for the prevention of other chemotherapy-induced adverse effects such as alopecia (hair loss) and this approach has been utilised in CIPN. It is hypothesized that cold-induced vasoconstriction decreases the delivery of chemotherapy through reduced perfusion to peripheral nerves in the hands and feet, exerting a neuroprotective effect. While current devices (i.e., pre-cooled, gel-filled gloves) have shown benefits in preventing/ reducing CIPN and resultant dysfunction, substantial barriers such as patient discomfort, side effects and logistical issues (difficulty integrating into the clinical workflow) prohibit routine use in clinical practice. Such devices have poor patient comfort and tolerability due to the very low temperatures involved. Due to the length of some chemotherapy sessions, a cold insert must be changed regularly, or several devices are required, which is time intensive for healthcare professionals.

Despite the evidence in support of preventive cooling for CIPN, a review of existing solutions highlights the limitations with current devices and some of the challenges in translating from research to routine adoption in clinical practice. The Elasto-gel, pre- frozen gel-filled gloves and socks for example, must be tightly fitted, held in close contact with the skin, are heavy and need to be placed in a specialised freezer prior to use. Patients experience significant pain/discomfort and are unable to tolerate the excessively cold temperatures (-25°C) resulting in high attrition. There are also safety concerns as inability to accurately monitor cooling has led to cases of frostbite and recall by the FDA. Integration into the clinical work has also been difficult due to staff time required to co-ordinate/replace repeatedly during chemotherapy and additional equipment requirement such as freezers.

Summary of the Invention According to a first aspect of the invention, there is described an apparatus configured to induce vasoconstriction through localised cooling, the apparatus comprising: at least one securing element for attaching the apparatus to a user’s hand or foot; one or more cold air conduits; a plurality of apertures for egress of cold air; and one or more retaining structures configured to retain at least one of the one or more cold air conduits and to position the at least one cold air conduit such that the one or more apertures are directed at the user’s digits.

The apparatus may comprise a plurality of apertures for egress of cold air. The plurality of apertures maybe perforations along a part of the length of the cold air conduit. Each of the one or more retaining structures may be configured to retain a respective cold air conduit such that the cold air conduit forms a closed loop configured to slide over the end of a user’s finger. Each of the one or more retaining structures may be configured to position a respective cold air conduit such that the cold air egressing from the one or more apertures is directed along the user’s finger towards the tip of the finger. The retaining structure may comprise a curved passage and wherein the cold air conduit maybe a flexible tube configured to pass through the curved passage. The retaining structure maybe configured to retain the end of the flexible tube in a recess. The plurality of apertures may be arranged along the length of the cold air conduit between the recess and the curved passage. The apparatus may comprise five cold air conduits and a hub unit configured to supply cold air to each of the five cold air conduits. The apparatus may comprise an inflow tube connectable to the hub unit and configured to supply cold air to the hub unit from a cold air generating system. The at least one securing element may comprise a first strap secured to the hub unit and configured to encircle the user’s wrist and a second strap secured to the hub unit and configured to pass between the user’s thumb and index finger.

The apparatus may further comprise an adjustable foot plate having a front plate and a rear plate longitudinally movable relative to the front plate. The front plate may comprise at least one retaining structure on each side of the front plate configured to retain the cold air conduit such that the cold air conduit forms an arc adjacent the user’s toes when the apparatus is worn on the user’s foot. The rear plate may comprise at least one retaining structure on each side of the rear plate configured to retain the cold air conduit such that the cold air conduit forms an arc adjacent the user’s heel when the apparatus is worn on the user’s foot. The rear plate may comprise a connection port for connecting an inflow tube to supply cold air to the cold air conduit from a cold air generating system. The apparatus may further comprise a toe cap releasably attachable to the front plate, the top cap configured to partially or completely enclose the user’s toes and comprising a groove configured to guide the cold air conduit.

Each of the one or more retaining structures may be configured to receive cold air inflow from a respective cold air conduit and may comprise at least one of the plurality of apertures for egress of cold air. Each of the one or more retaining structures may comprise a single ring shaped aperture or a single partial-ring shaped aperture. Each of the one or more retaining structures comprises a plurality of apertures.

According to a second aspect of the invention, there is described a system comprising: multiple copies of the apparatus according to the first aspect of the invention; a cold air generating system configured to supply cold air to each copy of the apparatus; and control circuitry configured to control operation of the cold air generating system. The cold air generating system may comprise a housing retaining a compressed air input and at least one vortex tube.

The system of the second aspect of the invention may comprise: two copies of the apparatus of according to the first aspect of the invention configured to be attached to a user’s hand; and two copies of the apparatus according to the first aspect of the invention configured to be attached to a user’s foot.

The system may comprise: a first vortex tube configured to supply cold air to the two copies of the apparatus configured to be attached to a user’s hand; and a second vortex tube configured to supply cold air to the two copies of the apparatus configured to be attached to a user’s foot.

The system may further comprising at least one infra red sensor configured to measure a temperature of the user’s digits and to transmit data corresponding to the measured temperature to the control circuitry. The system may further comprising at least one thermocouple configured to measure a temperature of the cold air supplied to the apparatus and to transmit data corresponding to the measured temperature to the control circuitry.

The system may further comprising an external device storing a computer program which, when executed by a processor of the external device, causes the external device to provide a user interface, the user interface comprising: information relating to a measured temperature of the user’s digits; information relating to a target cooling temperature; an interactive user element configured to allow the user to change a target cooling temperature, wherein the computer program is further configured to cause the external device to transmit data relating to a change in the target cooling temperature to the control circuitry of the system. The user interface provided by the external device may further comprise information related to a number of interruptions in the user’s cooling treatment and a duration of the or each interruption. Brief Description of the Figures

So that the general concepts set out in the foregoing sections can be more fully understood, embodiments thereof will be described with reference to the accompanying drawings, in which:

Figure i shows an apparatus according to the present invention, attached to a user’s hand;

Figure 2 shows the palm side of the user’s hand with the apparatus of Figure i attached; Figure 3a shows a retaining clip and end of a cold air conduit in more detail;

Figure 3b, 3c, and 3d show alternative designs for the retaining structure;

Figure 4a is a graph illustrating the results of testing of a prior art device and a prototype air cooling device;

Figure 4b is a graph illustrating the results of testing of the apparatus shown in Figures 1 and 2;

Figure 5a shows a corresponding apparatus according to the present invention for attachment to a user’s foot;

Figure 5b shows a toe cap for use with the apparatus of Figure 5a;

Figure 6 is a schematic illustration of a system comprising a cold air generator and two versions or copies of the apparatuses of Figure 1 and 2;

Figure 7a is a screenshot from a companion digital mobile application running on a user device showing a control screen prior to cooling beginning;

Figure 7b is a screenshot showing a second control interface displayed after cooling has begun; Figure 7c is a screenshot showing a summary screen displayed after cooling has ended;

Figure 8 is a flow chart illustrating operations of the application running on the user device and of the system and data transfer and storage; and

Figure 9 is a flowchart illustrating the steps of an exemplary method for inducing vasoconstriction through localised cooling.

Detailed description

Referring to Figure 1, an apparatus too is shown attached to a user’s hand. The apparatus too comprises a hub unit 102. When worn, the hub unit 102 sits over the back of the user’s hand and/ or over the user’s wrist. Attached to the lower surface of the hub unit 102 is an inflow tube 104. The inflow tube 104 supplies cold air to the hub unit under pressure from an air supply system (not shown). Extending from the top of the hub unit 102 are a plurality of cold air conduits 106. The hub unit 102 has an internal cavity allowing air to pass from the inflow tube 104 to the plurality of cold air conduits 106. In the depicted embodiment, each digit of the user’s hand has a respective cold air conduit 106. Cold air exits the hub unit 102 along each of the cold air conduits 106, which may take the form of flexible tubing.

The apparatus too also comprises a plurality of retaining structures 108 (also referred to as retaining clips). The retaining structures 108 retain the cold air conduits in order to hold them in place in the user’s fingers. The retaining clips 108 have a lower opening leading to a 90 degree curved passage ending in a side opening. The cold air conduit 106 is arranged to pass through the passage from the lower opening to the side opening and then be secured in a recess on the side of the retaining clip 108, so that the cold air conduit 106 forms a loop. The curved passage is configured to slidably receive the cold air conduit so that a user can push the cold air conduit 106 through the curved passage of the retaining clip 108; no special equipment is required to set up the deice too.

Securing the end of the cold air conduit 106 in the recess of the retaining clip 108 may cause the end of the cold air conduit to be blocked, or alternatively, the end of the cold air conduit 106 may already be closed or blocked by a bung or similar. The part of the cold air conduit 106 forming the loop comprises a number of perforations or apertures to enable the egress of the cold air. When properly fitted, these apertures direct the cold air at the user’s digits. In particular, the cold air is directed to flow along the user’s finger towards their fingertip, as indicated by the arrows in Figure 1. The portion of the user’s digit beyond the retaining clip 108 is therefore cooled by the outflowing cold air. The hub unit 102 is secured to the user’s hand by one or more securing elements 110, which in the depicted embodiments are straps. The straps 110 maybe adjustable and/or resilient. In one embodiment a first strap encircles the user’s wrist while a second strap passes between the user’s thumb and index finger. Figure 2 shows the palm side of the user’s hand with the same apparatus too attached.

The retaining clips 108 are not visible, since they are typically positioned on the back of the user’s fingers, where they are most easily accesses and do not interfere with finger usage. Each of the cold air conduits 106 is formed into a loop and held in this configuration by the retaining clip 108. The holes in the cold air conduits 106 which allow the outflow of cold air are shown in Figure 2 and the outflow of cold air towards the user’s finger tips is indicated by arrows. The evaporative cooling caused by the flow of cold air over the user’s digits causes localised vasoconstriction in the user’s fingers. This reduces the level of deposition of neurotoxic chemotherapy to the user’s fingers, reducing the likelihood and severity of CIPN. The cooling is localised to the area beyond the retaining clips 108 such that the rest of the user’s hand remains warm.

The features of the apparatus too result in a number of further advantages. The apparatus too is easy for a patient to put on and remove with minimal or no assistance. The loops formed by the cold air conduits 106 are easily placed over the ends of the fingers and slid down to the appropriate position. The straps 110 securing the device (in particular the hub unit 102) to the patient’s hand are also able to be tightened and loosened with one hand. After a brief instruction from a healthcare professional, most patients will be able to operate the apparatus too independently.

The size and position of the loops formed by the cold air conduits 106 is freely adjustable. More of the cold air conduit 106 can be pushed through the retaining clip 108 to increase the size of the loop. Conversely, the part of the cold air conduit protruding from the lower opening of the retaining clip 108 can be pulled to decrease the size of the loop. The apparatus is therefore easily adapted for use with different sized fingers and hands without any modification of the apparatus too being required. The position of the loops can also be freely set allowing more or less of the patient’s finger to be cooled and allowing easy adjustment for improved comfort. The angle of the outflowing air can also be adjusted by rotating the loop of cold air conduit 106 accordingly. When the loop is made smaller, some of the apertures/perforations are covered by the curved passage of the retaining clip 108. This arrangement maintains the efficiency of the device. In some embodiments, the amount by which the loop can be adjusted is limited by the length of the curved section of the retaining clip 108. A further advantage of the apparatus too is that the patient’s fingers are kept free, as can be appreciated from Figure 2. Some slack can be maintained in the cold air conduits 106 such that the patient retains to ability to flex their hand and fingers, resulting in improved comfort. The patient also retains most of the use of their hands, for example, they can continue to hold objects or operate a touch screen while using the apparatus. It will be appreciated that a system for patient use would typically include two versions of the apparatus too, one configured for the right hand and one configured for the left hand. Both versions of the apparatus may be connected to the same cold air supply, however it may be possible to independently control the temperature of the air supplied to each version of the apparatus too.

Figure 3a shows the retaining clip 108 and end of the cold air conduit 106 in closer detail. The cold air conduit 106 is a flexible tube. In Figure 3a, part of the retaining clip 108 is cut-away to show the position and depth of the recess 300 in the side of the retaining clip 108.

In use, the patient or a healthcare professional would first place the loop of cold air conduit 106 around each of the patient’s fingers. For the first time use of the apparatus too it may be necessary to push the end of each cold air conduit 106 through the lower opening of the retaining clip 108 and to form the loop by securing the end of the cold air conduit 106 in the recess 300 in the side of the retaining clip 108. After the loops are attached to the patient’s fingers at the correct location, the loop can be tightened if needed to ensure secure attachment. The cold air supply is then activated, either by manually operating the cold air supply or using a software application to cause the air supply to be activated. The temperature of the supplied air can also be set and adjusted at this point and during the treatment.

Referring now to Figures 3b to 3d, alternative designs for the retaining structure are shown. In the second design 302 shown in Figure 3b, the retaining structure has the shape of tapered ring (or hollow truncated cone) and may have a gap. This allows it to fit onto fingers having a range of different sizes, but imposes some limit on the freedom of positioning of the retaining structure. The retaining structure 302 maybe made of a somewhat resilient material, which combined with the optional gap allows the retaining structure 302 to expand a little. The retaining structure 302 has an annular cavity at the base and an inlet port 304 in fluid communication with the annular cavity. The end of the cold air conduit 106 is inserted into the inlet port 304 to fill the annular cavity with cold air. The retaining structure 302 has a partial ring shaped slit or a series of holes set in a partial ring shape along the top edge of the structure, to allow egress of cold air. In the third design 306 shown in Figure 3c, the retaining structure takes the form of an expandable ring. The retaining structure 306 has a toothed band which is able to slide in and out to adjust the size of the ring. This design is somewhat more intricate and more costly to manufacture. Also, the cold air outlet has the form of a partial ring, but does not extend to the part of the structure having the toothed band. It is also possible to partially or completely enclose the fingertip of the user, which may increase the efficiency of the cooling and uniformity of the cooling. Figure 3d shows a fourth design 308 in which the retaining structure has the form of a finger cap which completely or partially encloses the end of the user’s finger. The retaining structure 308 has an inlet port 310 leading to a passage which runs to the top of the finger cap. The cold air conduit 106 is connected to the inlet port 310 and may pass up through the passage. Cold air egresses at the top of the finger cap and flows back along the user’s finger. The efficacy of cooling may be increase by this design, but the user does not retain use of the fingers and several different sizes of cap must be manufactured and made available, increasing manufacturing costs and impacting ease of use of the apparatus.

From physiological investigations and research studies in preventive cooling, it is suggested that therapeutic cooling occurs at approximately 22°C. Modelling has been performed suggesting that a therapeutic cooling temperature of 22°C could be achieved using air at io°C.

Figure 4a is a graph 400 illustrating the results of testing of a prior art device, as mentioned in the background section and a prototype air cooling device (not shown). The prior art device comprises a pre-cooled, gel-filled glove at sub-zero temperatures, marketed under the tradename Elasto-gel. The prototype air cooling device (not shown) comprises a chamber with an opening to allow the user’s hand or foot to be placed inside the chamber. One or more walls of the chamber comprise a 3D printed insert designed to conform to the body shape (of the hand or foot). The insert is designed to provide multiple jets of air at a velocity of approximately Im/s through multiple tapered nozzles over a specified area of the skin. The insert is fed compressed air from a flexible line at a variable pressure of 20-40psi that has been chilled via a vortex tube to 10-15 Celsius. The chilled air is piped into a small chamber above the insert, so that it can then exit through the tapered nozzles. The prior art device trace 402 shows cooling to below 10C, followed by gradual warming.

The prototype device trace 404 also shows rapid and effective cooling to a therapeutic level, without the use of sub-zero temperatures. Figure 4b is a graph 406 illustrating the results of testing of the apparatus too shown in Figures 1 and 2, comprising the retaining structure 108 shown in Figure 3a. The graph 406 is a plot of measured patient skin temperature against time. The upper trace 408 shows the temperature of the index (first) finger. The second trace 410 shows the temperature of the ring (fourth) finger.

As can be seen, the skin temperature of both the index finger and ring finger decreased to below 22°C in under two minutes. The measured temperature continued to drop to between 18°C and 20°C after 4 minutes. At approximately 5 minutes the cooling was stopped, and the skin temperature slowly increased, but remained below 22°C in the fingers for at least a further 3 minutes. These results demonstrate the ability of the apparatus too to use cold air to locally cool the fingers of the patient to a therapeutic level for an extended period of time, without the risk of tissue damage from excessive cold. The patient also retained full use of their fingers during the test. The time delay in the patient’s fingers warming up above 22°C also allows for the patient to remove the apparatus too to take short breaks from the therapy, move around etc. without impacting the overall effectiveness.

During this test, it was also noted that the temperature of the patient’s palm remained high.

As well as the apparatus too shown in Figures 1 and 2, a corresponding apparatus 200 has been developed for providing air cooling to parts of the user’s foot. The apparatus 200 is shown in Figure 5a and comprises a front plate 202 and a rear plate 204, which support the user’s ball and heel of the foot respectively. Both the front plate 202 and rear plate 204 have strap attachment points 206. The straps (also referred to as securing elements) are omitted for clarity, but may be of any suitable type and act to secure the apparatus 200 to the user’s foot. The front plate 202 and the rear plate 204 are connected together but can be moved longitudinally relative to each other to allow for different sizes of foot to be correctly and comfortably positioned on the plates. The apparatus 200 has a number of retaining structures 108 for holding and positioning the cold air conduit 106. In the depicted embodiment, each of the front plate 202 and rear plate 204 has two retaining structures 108, one on each side, taking the form of partially or completely enclosed passages. The cold air conduit 106 passes through each of the retaining structures in turn and forms a toe loop 206 and a heel loop 208. The end of the cold air conduit 106 is inserted into a recess 210 on the side of the rear pate 204. The size of the toe loop 206 and heel loop 208 can be freely adjusted by adjusting the amount of cold air conduit 106 between each of the retaining structures 108. The portions of the cold air conduit 106 forming the toe loop 206 and heel loop 208 have a number of apertures to allow egress of cold air towards to the user’s digits (toes) and heel. In some embodiments, only the toe loop 206 may have apertures. The direction of the cold air can also be adjusted with a high degree of freedom by twisting the cold air conduit 106. The apparatus 200 is easy for a patient to put on and remove with minimal or no assistance. The patient can verify that the cold air from the apertures is directed correctly and make adjustment if necessary. The straps (not shown in Figure 5a) securing the apparatus 200 to the patient’s foot are also able to be tightened and loosened with one hand. After a brief instruction from a healthcare professional, most patients will be able to operate the apparatus 200 independently.

The patient also retains some usage of their feet. For example the patient is able to stand up on the front and rear plates and lift their feet. This means that the patient does not needs to remain stationary for the duration of the therapy, or interrupt the therapy to engage in some movement.

The apparatus 200 may optionally be fitted with a removable toe cap 500, shown in Figure 5b. The toe cap 500 is shaped to fit over the user’s toes and abut or releasably connect to the front plate 202. The toe cap 500 has a groove 502 to guide the cold air conduit 106 and ensure it remains correctly positioned. The toe cap 500 may increase the efficacy of the cooling of the user’s toes.

It will be appreciated that a system for patient use would typically include two versions of the apparatus 200, one configured for the right foot and one configured for the left foot. Alternatively, the two apparatuses 200 may be identical. Both of the apparatuses 200 may be connected to the same cold air supply, however it may be possible to independently control the temperature of the air supplied to each apparatus 200.

In a full system for patient use, two version of the apparatus too for attachment to the hands and two versions or copies of the apparatus 200 for attachment to the foot may be provided, along with the means for generating and delivering the cold air and controlling operation of the system. Such a system 600 is depicted schematically in Figure 6. The system 600 comprises a housing 602. Contained within the housing 602 are a first vortex tube 604 and a second vortex tube 606. The housing 602 also comprises a compressed air input 608. In some embodiments, the pressure provided to the vortex tubes is between 5-7 bar (70-100 PSI) and the vortex tubes may have an output of 300 litres per minute. Inside the housing 602, a tube conveys the compressed air to the first and second vortex tubes. A solenoid valve 610 is disposed in the path between the compressed air input 608 and the first and second vortex tubes, to quickly start and stop the supply of compressed air to the vortex tubes. The solenoid valve 610 is controlled by control circuitry 612. The control circuitry may comprise a controller for sending command signals to the solenoid valve 610 and a wireless transceiver for communicating with an external device. Other circuitry components may also be present.

The output of the first vortex tube 604 is split into two inflow tubes 104, which each connect to an apparatus 100 for attachment to a user’s hands and which supply cold air from the first vortex tube 604 to the apparatuses too. Similarly, the output of the second vortex tube 606 is split into two inflow tubes 104, which each connect to an apparatus 200 for attachment to a user’s feet and which supply cold air from the second vortex tube 606 to the apparatuses 200. Therefore the temperature of the air supplied to the hands and feet can be varied independently. Each vortex tube may have a hot gas outlet or heat sink. The housing 602 may have one or more vents (not shown) through which hot air can be expelled.

The housing 602 also has an emergency shutoff button 614. The emergency shutoff button 614 may be prominently visible and easily accessible, for example on the top of the housing 602. In some other embodiments, an emergency shutoff button maybe provided on the hub unit 102, for easy access by the patient. When pressed, the emergency shutoff button 614 sends a signal to the control circuitry 612, which in turn shuts off the solenoid valve 610. Alternatively, the emergency shutoff button 614 may bypass the control circuitry 612 and send a signal directly to the solenoid valve 610.

There are several methods for controlling the temperature of the air output by the vortex tubes. Firstly, the length of the vortex tube may determine the temperature. Each vortex tube may comprise a plunger which is movable within the tube to change its length. The position of the plunger maybe controlled by a servo motor under the control of the control circuitry 612. Secondly, the pressure of the compressed air input into the vortex tube also affects the output gas temperature. In some systems it may be possible to vary the pressure of the input gas. For example the system 600 may comprise an additional pressure regulating mechanism between the compressed air input and the solenoid valve 610. This pressure regulating mechanism would also be under the control of the control circuitry 612. Thirdly, since the vortex tube expels both hot and cold air, an arrangement may be constructed in which the hot and cold air streams are brought back together at a mixing valve. The mixing valve is configured to regulate the hot and cold input to achieve a desired output temperature. Lastly, a heating element may be placed around the cold air output of the vortex tube to heat the cold air to a desired temperature. Those skilled in the art will appreciate that other method for cooling air for use in the apparatuses too, 200 are known and maybe used in place of the vortex tube. For example, an air conditioning system or liquid based cooling mechanism may replace the vortex tubes. In a clinical setting, the user may be seated in a chair, for example a reclining armchair. The cold air generating system, which in this instance may be an air conditioning unit, maybe partially or completely integrated with the chair. For example, the cold air generating system may be attached to the rear of the chair and may have in general a “U” shape, to allow the backrest of the chair to be reclined. Thus, the extra space which the cold air generating system occupies is kept to a minimum and the various tubes and wires connected to the cold air generating system do not present a trip hazard. The chair may have features which allow it to be easily moved, for example wheels/castors. In this manner the cold air generating system can easily be moved together with the chair. As mentioned, the control circuitry 612 of the system 600 may comprise a wireless transceiver for communicating with an external device. The wireless transceiver may use any suitable protocol for communicant such as WiFi (IEEE 802.11), Bluetooth, NFC, Zigbee, Ultra Wideband or any other suitable communication method. The external device may be a tablet or smartphone and may store and run an application for displaying information regarding the therapy and for controlling the temperature of the air reaching the apparatuses 100, 200.

The system 600 may also comprise sensors (not shown) for monitoring the temperature of the user’s digits and the temperature of the cold air being delivered to the apparatuses 100, 200. The temperature of the user’s skin maybe monitored by an infra red sensor (not shown), such as an IR camera. This maybe done continuously during the cooling or periodically. For example, the user may place their fingers periodically in the field of view of a thermal camera. Alternatively a thermocouple may contact one or more of the user’s fingers to continuously measure a temperature. This temperature information may be relayed back to the control circuitry 612, where it may be stored in a memory and/or transmitted onwards to an external device. The temperature of the cold air being delivered to the apparatuses too, 200 may be monitored by a thermocouple. Multiple thermocouples may be provided at the point where the inflow tubes 104 reach the apparatuses too, 200. The thermocouples may continuously monitor the temperature of the cold air. The control circuitry may also be configured to make a prediction of the user’s body temperature in their digits based on the temperature of the cold air reaching the apparatuses too, 200 and the duration of cooling.

A proximity sensor may also be provided to detect when the user is wearing the apparatus and to track wear time. The proximity sensor may be embodied as a capacitive sensor or a separate active IR sensor. The application can be downloaded by the patient in advance of their chemotherapy appointment. At the appointment, the patient may use the application to connect with the particular system 600 that they will be using. For example, the housing 602 of the system 600 may comprise a QR code which can be scanned. Once connected with the system, but before cooling starts, the application displays a screen 700 as shown in Figure 7a. The screen 700 shows the time remaining in the current therapy sessions, the current temperature of the hands and target temperature of the hands and a slider to allow the user to change the target temperature for the hands. The screen 700 also shows the current temperature of the feet and target temperature of the feet and a further slider to allow the user to change the target temperature for the feet. A start button is provided at the bottom of the screen 700. Interacting with the start button causes the control circuitry 612 to instruct the solenoid valve 610 to open and cooling to begin.

After cooling begins the application shows a second screen 702 as shown in Figure 7b. In the second screen 702 the user has set the target temperature for the feet to 2i°C. Any difference between the target temperature and the current temperature may be indicated visually on the respective slider. At the bottom of the second screen 702 are two buttons, to pause or stop the cooling session. If the user interacts with the pause cooling button, an overlay window may be displayed with two buttons for resuming the cooling sessions or stopping the cooling session.

From the first screen 700 or the second screen 702, the user may swipe to view another screen with live views of their hands and feet taken by a thermal imaging camera in the room. This may act to provide the user with further reassurance that the cooling therapy is working as intended. The thermal camera images may also act as the source for the current temperature information shown on the first and second screens. The current temperature information maybe collected periodically, for example the user may be requested, via the application or otherwise, to place their fingers in the field of view of a thermal camera. A similar instruction may be provided for the feet. Alternatively, the toe cap 500 may support a thermal imaging device directed appropriately to measure the temperature of the user’s toes.

The application may provide the option to view summaries of completed cooling sessions. An exemplary summary screen 704 is shown is Figure 7c. The summary screen 704 indicates the total cooling time and average temperature over that time. The average temperature may refer to the average target temperature set or the average measured temperature recoded. Alternatively, both values may be displayed. A simple chart showing the progression of the temperature over the session for each of the hands and feet is shown. The application described with reference to Figures 7a to 7c has the advantage that the user can be better informed regarding the progress and effectiveness of the cooling session and can monitor the current status of the session at any time. The user is also in control regarding when the cooling starts and stops and can pause the cooling during the session if desired. These features help with patient uptake of and engagement with the cooling therapy, leading to improved therapeutic outcomes.

Figure 8 is a flow chart 800 illustrating operations of the application running on the user device and of the system 600 and data transfer and storage. At step 802 the application on the user device presents a screen into which the user can enter personal details. At step 804, the application presents a data collection consent screen. When the user consents to collection of their data a nurse or other Healthcare Professional may confirm that the user has consented to data collection using the application at step 806. At step 808 the user device is used to scan a QR code to link the particular system 600 that will be used to the user device and application. After the link is successful, the application shows a start screen at step 810. The start screen has a button to start the cooling session. The application determines at step 812 whether the start button has been pressed. If the button has not been pressed, the start screen remains displayed. When the start button is pressed, the application displays a temperature selection screen in step 814. When the start button is pressed, the application on the user device also sends a signal to the system to cause the solenoid valve to be opened in step 816.

In this embodiment, the apparatuses too, 200 are provided with proximity sensors in the form of separate active IR sensors. These are used to detect whether the user is wearing the apparatus or not in order to allow the wear time to be recorded. After the solenoid valve is opened and cold air begins flowing to the apparatuses too, 200, the active IR sensor(s) provide data to the control circuitry in step 818. At step 820, the control circuitry checks whether there has been any change in the IR state (i.e. detect whether the user has taken off or put on the apparatus). If the current IR state is equal to the old IR state (yes at step 820) the process at the system 600 returns to step 818. If the current IR state is not equal to the old IR state (no at step 820) the process at the system 600 continues to step 822 in which the new IR state (apparatus on/apparatus off) is transmitted. The IR state information may be transmitted to an internal memory forming part of the control circuitry, or to an external memory 824, for example a memory forming part of the user device or to a third party device or server. Returning to the user device application, at step 826, while the temperature selection screen is displayed, a button input is received. As shown in Figure 7b, the button input may take the form of an instruction to change the target temperature of the cooling, via one of the sliders or an instruction to stop or pause the cooling, At step 828, the application determines if the button input was an instruction to vary the target temperature. If the button input was not an instruction to vary the target temperature (no at step 828), the process continues to step 830 in which the application determines if the button input was an instruction to stop cooling. If the button input was not an instruction to stop the cooling (no at step 830), the application continues to display the temperature selection screen in step 814. If the button input was an instruction to stop the cooling (yes at step 830), the application sends a signal to the system 600, which closes the solenoid valve at step 832, stopping the flow of cold air to the apparatuses too, 200. If the button input was an instruction to vary the target temperature (yes at step 828), the process continues to step 834, in which an instruction to update the target temperature setpoint is communicated. The instruction to update the target temperature setpoint may be sent to the control circuitry directly or indirectly. As a result of receiving the updated the target temperature setpoint, the control circuitry updates the control temperature setpoint in step 836. The control temperature setpoint refers to the temperature of the cold air reaching the apparatuses too, 200.

At step 838, the thermocouple(s) measure the temperature of the cold air reaching the apparatuses too, 200. This information is transmitted in step 822. The current temperature information as measured by the thermocouples(s) may be transmitted to an internal memory forming part of the control circuitry, or to an external memory 824, for example a memory forming part of the user device or to a third party device or server. At step 840 the system 600 determines whether the current temperature (of the cold air as measured by the thermocouple) is equal to the control temperature setpoint. If the temperatures are not equal (no in step 840), the system 600 controls the servo motor to adjust the length of the relevant vortex tube (hand or feet) accordingly in step 842. The process then returns to step 838, reading the cold air temperature by the thermocouples. If the current temperature is equal to the control temperature setpoint (yes in step 840), the system communicates this fact to the application, which displays the temperature selection screen (step 814) and no further adjustment of the vortex tubes is made. At any time during the process, the emergency shutoff button 614 may be pressed in step 844. If this occurs, the system 600 closes the solenoid valve at step 832, stopping the flow of cold air to the apparatuses too, 200. When the system 600 closes the solenoid valve to stop the flow of cold air, whether after an instruction from the application or due to the emergency shutoff button 614 being pressed, the system uses the thermocouple(s) to read the cold air temperature and the active IR sensor to determine whether the user is wearing the apparatus or not in step 846. This information (including the time at which the cooling has been turned off) is transmitted in step 822. The information may be transmitted to an internal memory forming part of the control circuitry, or to an external memory 824, for example a memory forming part of the user device or to a third party device or server. At step 848 the system 600 then enters a sleep state. The application may display an end and/or summary screen, for example as shown in Figure 7c.

Figure 9 is a flowchart illustrating the steps of an exemplary method for inducing vasoconstriction through localised cooling. At step 900, an apparatus (such as that described above with reference to Figures 1, 2 and 5a) is attached to a user’s hand or foot using at least one securing element. The securing element may, for example, be one or more straps, such as straps 110 shown in Figures 1 and 2. However, any suitable method for securing the apparatus to the user’s hand or foot hand may be used. The straps 110 maybe adjustable and/or resilient. In one embodiment of an apparatus for attachment to the user’s hand, a first strap encircles the user’s wrist while a second strap passes between the user’s thumb and index finger.

The apparatus comprises one or more cold air conduits, a plurality of apertures for egress of cold air and one or more retaining structures configured to retain at least one of the one or more cold air conduits. The retaining structures may comprise any of the retaining clips 108 described above with reference to Figures 1, 2, 3a and 5a or the alternative designs described above with reference to Figures 3b to 3d.

At step 902, the at least one cold air conduit is positioned such that the one or more apertures are directed at the user’s digits. The way in which the least one cold air conduit is positioned will depend on the design of the retaining structure being used. At step 904, cold air is supplied to each of the one or more cold air conduits from a cold air generating system. The cold air generating system may for example be an air conditioning unit or a vortex tube. The method may continue with optional temperature monitoring and adjusting steps. For example, the method may further comprise measuring a temperature of cold air reaching the apparatus. This may be achieved using a thermocouple or other temperature sensor near one or more of the apertures. The method may further comprise receiving an instruction to change a target temperature of the cold air reaching the apparatus. This instruction may be received by a controller of the cold air generating system and may result from a user input directly on a user interface of the cold air generating system, or may result from a user input on an application running on an external device, which then transmits the instruction to the controller of the cold air generating system. The method may then comprise adjusting the temperature of the cold air being supplied by the cold air generating system according to the received instruction.

Alternatively, or in addition, the temperature of the user’s skin may be directly measured and used to adjust the cooling procedure dynamically. In this regard, the method may further comprise defining an upper threshold skin temperature and a lower threshold skin temperature. The upper threshold skin temperature and lower threshold skin temperature may be defined in a memory accessible to the controller of the cold air generating system. Alternatively, the upper threshold skin temperature and lower threshold skin temperature maybe defined in an application running on an external device, which is configured to transmits instructions to the controller of the cold air generating system for controlling the operation of the cold air generating system.

The method may thus comprise measuring a temperature of the user’s skin on the user’s digit. This can be achieved using an infra red sensor configured to measure a temperature of the user’s digits and to transmit data corresponding to the measured temperature to the controller of the cold air generating system.

The controller of the cold air generating system is configured to provide cold air to the apparatus such that the measured temperature of the user’s skin drops below the upper threshold skin temperature. The upper threshold temperature may for example be a temperature associated with a therapeutic cooling effect.

The method may comprise continuing to monitor the temperature of the user’s skin on the user’s digit while cooling is performed and temporarily ceasing providing cold air to the apparatus when the measured temperature of the user’s skin drops below the lower threshold skin temperature. This may ensure that there is a greatly reduced risk of excessive cooling of the skin leading to nerve or tissue damage, or to excessive discomfort which may discourage user’s from continuing the cooling treatment. Once the measured skin temperature is again above the lower threshold temperature, the cooling may recommence to keep the user’s skin at or below the upper threshold temperature.

Reference numerals

100 Apparatus (Hand)

102 Hub unit

104 Inflow tube 106 Cold air conduit

108 Retaining structure/Retaining clips

110 Securing Element/Straps

200 Apparatus (Foot)

202 Front plate 204 Rear plate

206 Toe loop

208 Heel loop

210 Recess

302 Second retaining structure design 304 Inlet Port

306 Third retaining structure design

308 Fourth retaining structure design

310 Inlet port

400/406 Graph 402 prior art device trace

404 Prototype device trace

408 Upper trace

410 Second trace

500 Toe cap 502 Groove

600 System

602 Housing

604 First vortex tube

606 Second vortex tube 608 Compressed air input

610 Solenoid valve

612 Control circuitry

614 Emergency shutoff button

700 First screen 702 Second screen

704 Summary screen

Claims

1. An apparatus configured to induce vasoconstriction through localised cooling, the apparatus comprising: at least one securing element for attaching the apparatus to a user’s hand or foot; one or more cold air conduits; a plurality of apertures for egress of cold air; and one or more retaining structures configured to retain at least one of the one or more cold air conduits and to position the at least one cold air conduit such that the one or more apertures are directed at the user’s digits.

2. The apparatus of claim 1, wherein the one or more cold air conduits each comprise a plurality of apertures for egress of cold air.

3. The apparatus of claim 2, wherein the plurality of apertures are perforations along a part of the length of the cold air conduit.

4. The apparatus of any of claims 1 to 3, wherein each of the one or more retaining structures is configured to retain a respective cold air conduit such that the cold air conduit forms a closed loop configured to slide over the end of a user’s finger.

5. The apparatus of any of claims 1 to 4, wherein each of the one or more retaining structures is configured to position a respective cold air conduit such that the cold air egressing from the one or more apertures is directed along the user’s finger towards the tip of the finger.

6. The apparatus of any preceding claim, wherein the retaining structure comprises a curved passage and wherein the cold air conduit is a flexible tube configured to pass through the curved passage.

7. The apparatus of claim 6, wherein the retaining structure is configured to retain the end of the flexible tube in a recess. 8. The apparatus of claim 7, wherein the plurality of apertures are arranged along the length of the cold air conduit between the recess and the curved passage. 9. The apparatus of any preceding claim, wherein the apparatus comprises five cold air conduits and a hub unit configured to supply cold air to each of the five cold air conduits. to. The apparatus of claim 9, wherein the apparatus comprises an inflow tube connectable to the hub unit and configured to supply cold air to the hub unit from a cold air generating system. 11. The apparatus of any claim 9 or 10, wherein the at least one securing element comprises a first strap secured to the hub unit and configured to encircle the user’s wrist and a second strap secured to the hub unit and configured to pass between the user’s thumb and index finger. 12. The apparatus of claim 1, wherein the apparatus further comprises an adjustable foot plate having a front plate and a rear plate longitudinally movable relative to the front plate.

13. The apparatus of claim 12, wherein the front plate comprises at least one retaining structure on each side of the front plate configured to retain the cold air conduit such that the cold air conduit forms an arc adjacent the user’s toes when the apparatus is worn on the user’s foot.

14. The apparatus of claim 12 or claim 13, wherein the rear plate comprises at least one retaining structure on each side of the rear plate configured to retain the cold air conduit such that the cold air conduit forms an arc adjacent the user’s heel when the apparatus is worn on the user’s foot.

15. The apparatus of any of claims 12 to 14, wherein the rear plate comprises a connection port for connecting an inflow tube to supply cold air to the cold air conduit from a cold air generating system.

16. The apparatus of any of claims 12 to 15, wherein the apparatus further comprises a toe cap releasably attachable to the front plate, the top cap configured to partially or completely enclose the user’s toes and comprising a groove configured to guide the cold air conduit. 17- The apparatus of claim 1, wherein each of the one or more retaining structures is configured to receive cold air inflow from a respective cold air conduit and comprises at least one of the plurality of apertures for egress of cold air.

18. The apparatus of claim 17, wherein each of the one or more retaining structures comprises a single ring shaped aperture or a single partial-ring shaped aperture.

19. The apparatus of claim 17, wherein each of the one or more retaining structures comprises a plurality of apertures.

20. A system comprising: multiple copies of the apparatus according to of any of claims 1 to 3; a cold air generating system configured to supply cold air to each copy of the apparatus; and control circuitry configured to control operation of the cold air generating system.

21. The system of claim 20, wherein the cold air generating system comprises a housing retaining a compressed air input and at least one vortex tube.

22. The system of claim 20 or claim 21, comprising: two copies of the apparatus of any of claims 1 to 3 configured to be attached to a user’s hand; and two copies of the apparatus of any of claims 1 to 3 configured to be attached to a user’s foot.

23. The system of claim 22, comprising: a first vortex tube configured to supply cold air to the two copies of the apparatus configured to be attached to a user’s hand; and a second vortex tube configured to supply cold air to the two copies of the apparatus configured to be attached to a user’s foot.

24. The system of any of claims 20 to 23, further comprising at least one infra red sensor configured to measure a temperature of the user’s digits and to transmit data corresponding to the measured temperature to the control circuitry. 25. The system of any of claims 20 to 24, further comprising at least one thermocouple configured to measure a temperature of the cold air supplied to the apparatus and to transmit data corresponding to the measured temperature to the control circuitry.

26. The system of any of claims 20 to 24, further comprising an external device storing a computer program which, when executed by a processor of the external device, causes the external device to provide a user interface, the user interface comprising: information relating to a measured temperature of the user’s digits; information relating to a target cooling temperature; an interactive user element configured to allow the user to change a target cooling temperature, wherein the computer program is further configured to cause the external device to transmit data relating to a change in the target cooling temperature to the control circuitry of the system.

27. The system of claim 26, wherein the user interface provided by the external device further comprises information related to a number of interruptions in the user’s cooling treatment and a duration of the or each interruption.

28. A method for inducing vasoconstriction through localised cooling, the method comprising: using at least one securing element to attach an apparatus to a user’s hand or foot, the apparatus comprising (i) one or more cold air conduits, (ii) a plurality of apertures for egress of cold air and (iii) one or more retaining structures configured to retain at least one of the one or more cold air conduits; positioning the at least one cold air conduit such that the one or more apertures are directed at the user’s digits; supplying cold air to each of the one or more cold air conduits from a cold air generating system.

29. The method of claim 28, the method further comprising: measuring a temperature of cold air reaching the apparatus; receiving an instruction to change a target temperature of the cold air reaching the apparatus; and adjusting the temperature of the cold air being supplied by the cold air generating system according to the received instruction.

30. The method of claim 28 or claim 29, the method further comprising: defining an upper threshold skin temperature and a lower threshold skin temperature; measuring a temperature of the user’s skin on the user’s digit; providing cold air to the apparatus such that the measured temperature of the user’s skin drops below the upper threshold skin temperature; and temporarily ceasing providing cold air to the apparatus when the measured temperature of the user’s skin drops below the lower threshold skin temperature.