GB2404858A - Deep vein thrombosis and circulation therapy device having automatic activation - Google Patents

Abstract

The device 10 is used in assisting prevention of circulatory problems such as deep vein thrombosis DVT, and comprises a pair of contact electrodes 18 20 which may have electrically conductive adhesive or conductive gel layers 14, 16, the electrodes being connected to a controller 22 supplying electrical stimulation signals and powered by battery 24. The controller is also connected to switch means 26 which may be a direct push switch or may be an ambient pressure actuated switch which can detect the lowered air pressure of a pressurised aircraft cabin. Alternatively (see figures 5a-c) the switch means may comprise removable interference tab 226. The device provides electrical stimulation pulses preferably to the calf muscles of a user to stimulate blood flow during long-haul aircraft flights.

Description

1 2404858 1'3047 1 8(,B Electrical Muscle Stimulation Device I'lc

invention relates to a self adhesive and preferably disposable device for cl'l-ccting' electrical muscle stimulation which is usable in particular, but not cxchsixely to help prevent circulatory problems such as Deep Vein Thrombosis ( 1)V'l').

I)cep Vein 'I'hrombosis and other circulatory ailments are known particularly to 'ccur c-luring or as a result of extended periods of muscular inactivity. Such periods can occur l-or example during long haul flights when passengers often get little or no exercise liar several hours and this is compounded by cramped conditions which r squire the lower leg to be bent at the knee which is thought to restrict blood flow to to lower leg. Such prolonged periods of inactivity are thought to lead to a number ol' medical conditions including ankle edema, cramps and potentially death occurring through for example a pulmonary embolism as a result of DVT.

11 is 1nowr to help prevent such circulatory problems by providing devices which bassist 'muscular activity particularly to the calf muscles. Such devices can by simple ncclanical tools to assist in constricting the calf muscle or applying massage tcclniclues to to calf muscle. It is also known to use electrical muscle stimulation to stimulate the nerves in the calf muscle thereby to cause muscle contraction which lclps to stimulate blood flow. However, such known devices have not been widely loptcl to date. in the case of manual devices, these are not readily used by all psscncrs due to the effort and/or time involved in effective treatment. In relation (is electrical devices, these have to date proved to be fairly complex and/or sophisticated devices which are therefore necessarily expensive and not readily available to all passengers.

\cc'rcliuglv. it is an oh ject of the present invention to provide a device which helps revc',l circulatory ailments through the use of electrical muscle stimulation which is cast to use, inexpensive to manufacture and/or readily available for passengers of I loins lurul flights.

\cc'rding to a first aspect of the invention, there is provided a device for assisting prevention ol circulatory problems comprising a pair of electrodes arranged to be Actable in electrical contact with a user, a controller tor communicating an electrical signal to the electrodes operably to provide electrical stimulation to the riser. and a switch operable automatically to actuate the controller when the user prepares the device tor use or applies the device to him or herself.

13e',elicially the controller can be automatically actuated for example on removal of i releasable tab or snip such as a releasable strip for covering during storage an cilcsive layer which is used to attach the device to the user. Accordingly' a sensor c be provided for determining when the releasable strip has been removed such as all electrical device whereby a circuit is closed e.g. through the use of a microswitch fin r crease of the releasable strip and/or on application of the device to a user.

/\cc'rding to another aspect of the invention there is provided a device for use in ssisting prevention of circulatory problems comprising a pair of electrodes arranged lo be locatable in electrical contact with a user, a controller for communicating an electrical signal to the electrodes operably to provide electrical stinnlation of the user, and a pressure actuated switch operable to actuate the coiLrol ler on detection of a predetermined pressure change or pressure level.

13c'clicially- the pressure actuated switch is operable to determine a change in the Mu r,unding ambient atmospheric pressure. Accordingly, the pressure actuated s\vitcl can be set to determine a decrease of say 20% in the surrounding aslnosphcric pressure thereby to indicate that an aeroplane is cruising at an altitude <,rc,t-er than 2.()()() metros or so.

According to another aspect of the invention there is provided a disposable device lor rise in assisting prevention of circulatory problems comprising a pair of clecir:lcs arranged to be locatable in electrical contact with a user, an controller t'or connnicathg an electrical signal to the electrodes operably to provide electrical sti'lati-'n Blithe user and a flexible support member adapted to carry the pair of electrodes and controller both during storage and in use.

1-3cneiicially, the support layer is adapted to be releasably attachable to part of the Serbs lady such as the rear surface of a calf muscle.

I'lc Invention will now be described, by way of example only, with reference to the accompanying drawings, in which: I'irc I is a schematic front elevation view of a first device according to the Et.

I 'arc 2 is a schematic side elevation view of the device shown in figure 1, I:igure 3 is a front elevation view of a second device according to the invention, I'iurc 4 is a side elevation view of the device shown in figure 3, I'irc shows three dil'ferent views of a third device according to the invention, t\(:] I'i're ( is a schematic block diagram of components making up the control circuit lor a 1cvice according to the invention.

llclerring t' I:igure I there is shown an electrical muscle stimulation device 10 arlaptccl Or attachment to a user's calf muscle thereby to provide electrical stin4ilalion to a users nervous system in the region of the calf muscle in order to <rssisl in muscle stimulation and help circulatory flow. Device 10 comprises a lick 12 I'or contacting a user's skin which surface comprises two regions 14 and I t o1' electrically conductive adhesive layers. For examples layers 14 and 16 can conic an electrically conductive tape such as provided by 3M. Electrically cdctive layers 14 and 16 provide electrically conductive contact between electi-otles I X and 20 respectively and a user's skin in use. Alternatively, layers 14 1 1(, can comprise electrically conductive gel such as a hydro gel which might comprise a high chloride content, for example RG63B from LecTec Corporation of Minnesota, lJSA. The gel can have some adhesive properties but which adhesion Itchy be assisted by a further adhesive but non- conducting layer to surface 12 hctwcc'i layers 14 and 16.

I Iccttodcs 18 and 20 are spaced apart on device 10 and electrically isolated from c another to enable electrical stimulation of a user in use. Such electrical sthntilation is provided by controller 22 connected to electrodes 1B and 20 for exanple by flexible wiring such as conductive ink strips. Device 10 further cr,np ises a power source 24, such as a battery, and a switch 26.

lclerri, to l'igure 2 it can be seen that device 10 is preferably constructed using a Or of substrates to support the electrical component. Electrodes 18 and 20 are Tolerably applied to the outer surface of a flexible supporting layer 28 which might be; breathable elastomeric material having a few millimetres thickness. Pret'erably bloc c,ntroller 22, battery 24 and switch 26 are located on the opposite sides of SI:O I layer 2X and preferably firmly located in position by a second support layer () \licl again might be of a breathable elastomeric material. Preferably support layers 28 and 30 are bonded together for example using an adhesive. Preferably, an ,utc- releasable strip 34 is provided to cover contact surface 12 prior to use and iglt for example comprise a slightly opaque vinyl material which is relatively rclcshlc by leased t'rom the adhesive on contact surface 12. Additionally, it is possible to apply a different outer membrane 32 to the outer surface of support layer () thereby to provide greater protection to device 10 for example during l'sportation and/or in use. Preferably, releasable layer 34, the outer surface of support l'ycr 3() and/or the outer surface of outer membrane 32 are adapted to carry ri'-cl knitter such as branding and/or other advertising material.

lit Discs switch 26 is actuated to effect power supply from battery 24 to controller 22 Lick provides an electrical signal to electrodes 18 and 20 which thereby in use to pr,vicle electrical muscle stimulation to a wearer.

Whilst switch 26 can be manually operable such as on depression by the user from Alec outside of device 10 through support layer 30 and/or comprise other manually operated switches, preferably switch 26 comprises a pressure actuated device, l,ssibl in series with a manually or automatically actuated primary on/off switch, wlcrebx device 10 is turned on only when predetermined pressure conditions are Ictcctcl by pressure switch 26.

l fir ex.rmplc' aircraft cabin pressure is generally maintained at a pressure somewhat lo\ er Ala that of atmospheric pressure at sea level. It is known that some aircraft prcssu-isc the cabin to approximately 70 to 80% of atmospheric pressure at sea level: that is approxhnately 78,000 Pa compared to 101,000 Pa at sea level. This prcssre is roughly equivalent to air pressure at about 2,000 metros (8000 feet).

According tic one embodiment, pressure sensor 26 is calibrated to detect the pressure ill;'lpr'xi'Mately SO% or less than one atmosphere thereby to commence operation >l lcvice I () for electrical muscle stimulation for a user once an aircraft has climbed lo; prelelermined height.

l lo cleclrical stimulation provided by controller 22 through electrodes 18 and 20 c; he i' constant pulsed signal for the period in which the pressure sensor switch lctcrnincs flat the pressures is below a certain level as described above, or <'tlerwise the device is actuated. Alternatively, periodic pulsed signals can be lrovicIecl during this time period. Preferably the signal is a low frequency signal of; sul'liciet power to provide electrical muscle stimulation thereby to stimulate blood 11-v. I or cxanple pulses between 0.01 Hz and I Hz can be provided for duration's I 1'scveral seconds or several minutes with a rest period between bursts of pulses in bloc,rder oftcns oi'seconds to several minutes.

exanple stimulation might be provided for 8 seconds per minute i.e. having a :9 second break in pulses to allow for muscle relaxation, or might be t'or a conti','o's period of 5 minutes with a 10 minute rest. In another form, stimulation levels can be varied in intensity automatically by controller 22 so that particularly Ruin long periods of burst of pulses whether continuous or discontinuous for; example for 5 minutes as stated above. The higher level of intensity is preferably oticeablc to the user and might be provided for between 1/10 or 1/100 of the period ill \vlicl stimulation takes place thereby to enable a user to know that the device is still working. Additionally, a simple light indicator such as an LED might be pr ovidcd for this purpose.

E3enel'icially the change in level of stimulation can be ramped for a simple smooth i,creasc in intensity of stimulation. Alternatively, a number of levels of pulse; amplitude can he used whereby the controller simply makes step changes between the dil'lerent levels thereby to vary the intensity of stimulation in step changes from one level to the next. In one example, only two levels are provided, namely a lower arid higher level. Additionally, it is possible that the or a lower level of stimulation I call to provided continuously throughout the use of the device with higher levels Len 'secl intermittently.

\cccrclinly controller 22 preferably comprises a frequency generator such as a simple crystal oscillator, a timing device and programmable device such as a micro Processor or appropriate ASTC in communication with switch 26 and power source 4 Lherely to enable generation of pulse signals in communication with electrodes 18 find 2(). Power source 24 can for example comprise a simple l;S volt DC battery Sol as a watch battery for example, which when device 10 is fully operational, Wilt have a maximum duration of between 10 and 20 hours.

/\ccordingly it will be appreciated that the nature of the electrical components 26, 92 Anal 24 is such that they are readily manufactured and easily assembled with other csily l:.lricated components such as support layers 28 and 30 thereby to provide a cl'ticl\; inexpensive device 10 which is specifically adapted to enable single use Ed r eaclv clisposability after such use by an airline passenger for example.

Herring to leisure 1, it can be seen that device 10 is adapted to attach to the rear of c;-'ll' 'muscle approximately 2 to 5 centimetres below the knee joint and has an upper width Wl greater than the lower width W2. Width Wl can be about 130mm Ed width W2 in the order of 90 millimetres. Preferably height H in is the order of 1 7() ',illimetres.

llclerrin: to l'igures 3 and 4, there is shown a second embodiment of an electrical msclc stimulation device according to the invention. Device 110 is substantially similar to crevice lO shown in Figures I and 2 and accordingly, like components are l;helleLI with the same two digit reference prefixed with a number 1. In this cnlodinent a control unit 136 is provided for housing controller 22, battery 24 and s\\ itch 9(. I'rel'erably unit 136 has a battery access 138 such as a releasable closure Lick is removable to gain entry to a battery thereby to enable replacement of the lacer arid hence enable reuse of device 110. Battery access 1 38 might for example core substantially circular closure having an outer threading adapted to cú:age in a threaded aperture in control unit 136.

lcl'crrig tc, Figure 5, there is shown three different views of a third device lcc>rdi'g to the invention. Device 210 is somewhat similar to device 10 shown in liurcs I and 2 and accordingly like components are labelled with the same two Vigil rclerence prefixed with the numeral 2. In this embodiment, the overall shape al Alec crevice is a substantially flat oval shape adapted to attach to the rear of a calf rscle as Previously described and as shown in Figure Sc. In this embodiment, ciccirical components are again contained within a device between support layers 228 al 23(). l lowever, switch 226 is exposed to the user at the upper end of the levicc enallling easy actuation by the user of this easily attachable and readily clis'osalie electrical muscle stimulation device. For example, switch 226 might singly comprise a removable interference tab which once removed enables electrical connection between battery and controller.

As can be seen in Figure 5a, multiple electrodes are provided which run up and Disown the crevice. Accordingly, electrical stimulation is provided laterally across the call muscle (' between pairs of electrodes 216a and 218a, and 216b and 218b. Each lectrocle is in electrical contact with the calf muscle but otherwise electrically is'l.lecl from one another at the actual contact surface 212.

( Plier 'rrangcments ol electrode are possible including use of electrically cductivc regions woven or integrated in the support layer. The regions can be h'wc anti below one another, side by side or in other configurations.

lclerrig to l igure 6, there is shown a schematic block diagram of the electrical count fair use in a device according to the present invention.

lid Dirtier to accommodate the different types of use of the device according to the il)VCllti(!' a relatively sophisticated switch 26 can be provided having one or more <'l Alec l'llo\ving features. As shown, switch 26 can comprise two parallel <rr.ncncnts of switches. In the first arrangement, switch 26 can comprise an tolaticaliv actuated switch and/or a manually operable switch 40 as described in rcllio l' switch 26 shown in Figure 2 or indeed such as the switch 226 shown in 1 insure which is a mechanically releasable interference switch. Switch 40 can be provile1 in series with a second switch 42 such as a pressure sensitive switch as I (1LSCrjUeCI in relation to switch 26 in Figure 2. Beneficially, switch 40 prevents to;tic actuation of a device 10 during a flight when the device 10 is not in use 1!' scar. Additionally, switch 40 and/or switch 44 can be automatically actuated SWI[LI]CS wlich lor example are actuated when a user removes releasable layer 34 (1.-l fir iclcccl 234) from the device according to the invention just prior to application of the device to a user's skin. Accordingly, switch 40 or 44 might comprise a simple micro switch device which is actuated on separation of the r cleanse strip 34 from contact surface 12. For example, such a micro device might be iscrLed in support layer 28 adjacent controller 22 with the spring loaded cclanically actuated arm in contact with release strip 34 thereby enabling cLrlion on removal of strip 34. Similarly, such an automatically actuated switch flight comprise an electrical contact provided in release strip 34 which once rcnoved actuates device 10. Further, battery 24 might be an air actuated battery Rich is only operable when exposed to air such as a zinc air battery. Accordingly, bloc relevant surface of battery 24 can be provided to the outside surface of support l.y er.() anal possibly comprise a specifically designed release strip of its own which c'hles cxposwre ol the relevant surface of battery 24 to the air at the outer surface <1 support layer 30 and/or outer membrane 32.

Claims (1)

1. Claims I A device used in assisting prevention of circulatory problems

   comprising pair ol electrodes adapted operably to be in electrical contact with a user, a controller lor communicating an electrical signal to the electrodes operably to lyres\ idc electrical stimulation of the user, and a switch operable automatically to ctritc the controller when the user prepares the device for use or applies the device to him or herself: :2. /\ device according to claim 1 comprising a releasable strip or tab which wlc' r emoved from the device effects operation of the switch thereby utatically to actuate the controller.

   it. A clerics according to claim 2 wherein the releasable strip covers an llcsive region of the device during storage, which adhesive region is adapted rcleasably to attach the device to a user in use.

   4. A device according to any preceding claim wherein the switch comprises nicroswitch.

   a. A device according to any of claims 1 to 3 wherein the switch comprises electrical contact which is moved in preparing the device for use or applying the device to a user.

   (a. A device accordhg to any ol claims 1 to 3 wherein the switch comprises air operated battery.

   7. A device according to any preceding claim wherein the switch comprises ' I-es.srre actuated switch operable to actuate the controller on detection of a lredetcrnined pressure change or pressure level.

   S. A device for use in assisting prevention of circulatory problems comprising a pair oi electrodes arranged to be locatable in electrical contact with Descry a controller for communicating an electrical signal to the electrodes <'pcrably lo provide electrical stimulation of the user, and a pressure actuated witch operable to actuate the controller on detection of a predetermined pr cssurc change or pressure level.

   ). A device according to claim 7 or 8 wherein the pressure actuated switch is preset to detect a predetermined percentage change in surrounding ambient pressure such as a 20 , decrease below atmospheric pressure at sea level.

   1(). A disposable device according to any preceding claim comprising a flexible support member adapted to carry a pair of electrodes and controller during storage and in use.

   I 1. A disposable device tor use in assisting prevention of circulatory problems comprising a pair of electrodes arranged to be locatable in electrical contact with a user, an controller for communicating an electrical signal to the electrodes operably to provide electrical stimulation of the user and a flexible support member adapted to carry the pair of electrodes and controller during suffrage and in use.

   1?. A device according to claim 10 or 11 comprising a further flexible support member adapted to cover the controller in use and/or to provide further r -,hustncss to the device.

   1. A device according to any preceding claim comprising a battery having sillicicnt power to operate the device for a predetermined period oftime such as entire clean Afar hours, more than ten hours, and/or preferably up to twenty hours.

   14. A device according to any preceding claim wherein the controller generates a series of pulses to the electrodes which pulses are continuous.

   15. A device according to any of claim 1 to 13 wherein the controller conuuicates an electrical signal comprising intermittent bursts of pulses and wherein the bursts of pulses are generated for periods of between a few seconds and several minutes and/or are generated between rest periods of between several seconds and several minutes such that the ratio of periods of stimulation lo On-stimulation are preferable between 5 and 50%, more preferably between 5 anal 33% and in two specific forms 13% and 33%.

   I (i. A device according to any preceding claim wherein the controller generates an electrical signal of variable amplitude to the electrodes which variable amplitude can be a simple ramped variation in amplitude both Creasing and decreasing in amplitude during the operation of the device, and/or comprises two or more levels between which the controller changes the amplitude electrical signal at predetermined or random times.

   17. A device according to any preceding claim wherein after actuation of the controller, the controller is programmed to wait a predetermined time before effecting transmission of an electrical signal to the electrodes, or to await a -I-'urthcr signal such as from a pressure switch before effecting transmission of an electrical signal to the electrodes.