AU719881B2 - A medical device for the hand - Google Patents

Description

WO 96/32085 PCT/GB96/00839 A MEDICAL DEVICE FOR THE HAND FIELD OF THE INVENTION This invention relates to a medical appliance and particularly to an appliance for applying local pressure to a portion of the hand for the purpose of stimulating blood circulation through enhanced venous or arterial flow in order to combat such afflictions as ischaemia, pain swelling, algodystrophy and venous thrombosis.

BACKGROUND OF THE INVENTION A venous pump mechanism is known in the region of the hand essentially including the proximal phalanges of the digits and thumb and the adjacent regions of the palm and dorsum; this mechanism is naturally brought into operation upon a tight doubling of the fist whereupon venous return flow ensues from the entire arm.

It has been established that by periodically squeezing this region without requiring a patient to double his fist, i.e. by external application of squeezing essentially local to this region, venous return flow may be efficiently stimulated even in the case of a degree of venous obstruction in the wrist or elsewhere in the involved arm.

Additionally it has been established that such externally applied squeezing pressure can also be accompanied by an improvement in arterial flow in the involved arm.

In European Patent No. 0 228 768 there is disclosed an inflatable mitt for engaging the proximal phalanxes of the fingers and thumb of the hand and adjacent regions such that upon periodic pressurisation, localised application of a squeezing force may be applied to those parts to stimulate venous flow.

In related European patent application No 89305062.5 there is disclosed a circumferentially tying inflatable bag shaped for radially inward active engagement solely with a human hand which may be cyclically inflated, the squeezing pressure then being held for a short period of time to stimulate arterial flow.

A further similar medical appliance is disclosed in "The Return of Blood to the Heart" (Second Edition) by Gardner and Fox (Published by John Libbey). On page 130, Figure 69 depicts a pneumatically compressible mitten, the mitten body being formed of slitted Neoprene and enclosing an inflation pad wherein Velcro straps are provided externally to direct the force of inflation towards the hand.

All these medical appliances suffer the disadvantage that although an efficacious increase in venous or arterial blood flow is achieved, all require that a glove or mittenlike structure be worn over the affected hand.

In cases to be treated by medical appliances of these types, the affected hand is likely to be painfully swollen and considerably less mobile than usual.

It is clear, therefore, that where the fingers of the hand must be manoeuvred through particular finger holes in a glove, or where the hand must be manoeuvred through the appropriate holes in a mitten, that the fitting process is likely to be both time consuming from the point of view of the medical practitioner and painful from the point o of view of the patient, and may in some cases be impossible.

A further necessity, of course, will be the requirement that a wide range of sizes of such medical appliances be kept to fit the range of sizes of hand encountered, both in terms of normal variation and degree of swelling.

It is an object of the present invention to overcome or ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative.

00..SUMMARY OF THE INVENTION 0° According to the invention there is provided a medical device for applying a •o 0 °venous or arterial blood flow enhancement pumping pressure to a human hand comprising an inflatable sealed enclosure for engagement with a human hand and means for selective admission of inflation pressure fluid into the enclosure to apply said pumping pressure including by means for securing the enclosure to a human hand to form an inflatable wrap, said securing means having first and second interconnectable securing lobes defining a peripheral extent including a thumb insert in its peripheral contour, and a third securing lobe connectable to either the first or second securing lobes ,or to itself around the wrist whereby the wrap may be secured around a human hand with '17' -3the distal ends of the fingers extending from the wrap such that upon inflation of the enclosure a squeezing action is applied to promote venous or arterial blood flow.

Unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

Advantageously, the present invention provides a medical appliance that can yield an equivalently efficacious promotion of venous or arterial blood flow in an affected hand whilst allowing a considerably improved ease of use both from the point of view of fitting the appliance and adjusting the appliance to the given size of hand.

The medical device of the present invention may be placed around the affected hand and fastened as required, so avoiding the difficult and painful process which is experienced when fitting devices of the prior art.

Preferably, in the retained position the inflatable sealed enclosure substantially 15 either circumferentially encloses the hand or engages the palm thereof.

In this way the appropriately selected regions of the hand may be squeezed.

Further preferably the securing means includes either a third lobe for securable attachment around the base of the thumb of the hand to one or both of the first and second lobes or a strap for securable attachment around the wrist.

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-4- In this way the wrap is secured around the hand to provide efficacious contact over a large part of the hand with the advantage that being secured either around the thumb or the wrist the wrap cannot slip or be forced off the hand during treatment.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example and with reference to the accompanying drawings in which: Fig 1 is a schematic view of a first embodiment of an inflatable wrap according to the invention; *Fig 2 is a schematic view of a hand placed on the device of Fig 1 in readiness for 10 the fastening of the device thereabout; Fig 3 is a schematic view of the device of Figs 1 and 2 fastened around the hand; Fig 4 is a schematic view of a second embodiment according to the invention; Fig 5 is a schematic view of a third embodiment according to the invention; Fig 6 is a set of schematic views of a fourth embodiment of an inflatable hand wrap according to the invention.

PREFERRED EMBODIMENT OF THE INVENTION The inflatable wrap shown in Fig 1 is provided with an inflatable bag 1 shaped for engagement with the relevant portion of the affected hand when in use. The shaping of the bag includes an indent 2 which is intended to be seated in the portion of the hand between the thumb and the index finger as is indicated in Fig 2.

The indent 2 defines a right-hand lobe 3 of the inflatable bag 1, with a left-hand lobe 4 defined by the left-most extension of the inflatable bag 1.

The inflatable bag 1 is formed from two portions of a flexible material having RJ appropriate airtightness characteristics which may or may not include ventilation holes 4a (not shown), sealed together on their respective perimeters save for an inlet 5 accepting an associated pressurised air feed 6 allowing the bag 1 to be inflated thereby.

The pressurised air may be fed from a pumping apparatus (not shown) having such operational characteristics as to allow inflation of the bag 1 to the required a.

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a a a a a. a a a a iS-) i't i~ WO 96/32085 PCT/GB96/00839 pressure, typically within two seconds. The inflation/deflation regime is discussed further below.

A base portion of the inflatable bag 1 is secured to an outer material layer 7 by any suitable means, for example sticking with double sided tape or a material such as Velcro, thus allowing repositioning, or by glue bonding to form the inflatable wrap. The form of the outer material layer 7 is also shaped for engagement with the affected hand, and includes an indent 8 corresponding to the inflatable bag indent 2 likewise for seating between the thumb and the lo index finger of the hand as illustrated in Fig 2. A right-hand lobe 9 is defined to the right of this indentation 8 with the left-most extension of the outer material layer defining a left-hand lobe 10. A further somewhat longitudinally extended lobe 11 is provided, extending downwardly and to the left of the thumb indentation 8.

The outer material may typically be an inelastic or only slightly elastic material, such as canvas, with an outer looped surface such as brushed nylon for engagement with a material such as Velcro and an inner substantially smooth surface for patient comfort. An intermediate layer of thin foam or cotton wadding may be interposed between the inner surface and the outer material for further patient comfort. All the above layers may be laminated together or joined to one another along their respective perimeters.

The left-hand lobe 10 of the outer material layer 7 and the downwardly extending lobe 11 are furthermore provided with tabs 12, 13 formed of a material such as Velcro which may securely engage the looped surface of the outer material layer 7.

In use, the affected hand is first placed over the device as is indicated in Fig 2 with the respective indentations 2, 8 seated against the portion of the hand between the thumb and the first finger, such that the thumb of the affected hand passes underneath the right-hand lobe 9 of the outer material layer 7.

The right-hand lobe 9 is folded around the affected hand in the direction of the arrow I, folding substantially along the neck of the lobe 9 thereby guiding the right-hand lobe 3 of the inflatable bag 1 as it moves. The right-hand lobe 3 of WO 96/32085 PCT/GB96/00839 6 the inflatable bag 1 then engages a portion of the back of the hand, being held in place by the overlapping right hand lobe 9 of the outer material layer 7.

The left-hand lobe 10 of the outer material layer 7 is folded over the hand in similar fashion in the direction of the arrow II guiding the left-hand lobe 4 of the inflatable bag 1 into contact with a further portion of the back of the hand.

As a result of folding over the respective right and left hand bag lobes 3, 4, the inflatable bag will now substantially circumferentially enclose the affected hand. Due to the greater lateral extent of the right and left hand lobes 9, 10 of the outer material layer 7 these respective lobes 9, 10 will now overlap one another.

Thus the left-hand lobe 10 of the outer material layer 7 may be secured to the underlying right hand lobe 9 of the outer material layer 7, typically by means of the engagement of the tab 12 with the looped surface of the right-hand lobe 9.

The longitudinally downwardly extended lobe 11 is folded around the base portion of the hand and thumb in the direction of the arrow III, thereby extending diagonally across both the left and right-hand outer material layer lobes 9, 10 whereupon it may be fastened to the outer surface of the left-hand lobe 10, as shown in Fig 3, again typically by means of engagement of the tab 13 with the looped surface of the outer material layer 7.

Consequently, the affected hand is substantially circumferentially enclosed by the inflatable bag 1 which is secured thereto by means of the interengageable lobes 9, 10, 11.

Since the lobes 9, 10, 11 are typically fastened by means of engagement of a tab 12, 13 with a looped surface, the inflatable wrap may easily be adjusted to fit a wide range of sizes of hand.

With the interengagement of the respective three outer material layer lobes 9, 11, the inflatable wrap effectively encompasses the portion of the hand required to be squeezed whilst allowing free and constant inspection of the fingers and thumb of the affected hand during treatment in respect oft for WO 96/32085 PCT/GB96/00839 7 example, circulation, nerve reaction testing and therapeutic progress in reduction of swelling.

In a second embodiment, as is shown in Fig 4, an adjustable wrist strap 14 connected to and extending from the body of the device and tethered around the wrist to itself by means of a tab 15 is used in place of the third lobe 11 to effect the adjustable securing of the inflatable wrap to the hand.

Furthermore, in place of the overlap of the respective lobes 9, 10 allowing the interengagement described above, any other suitable means to effect the secure connection of the lobes 9, 10 may be used.

If, having regard to a third embodiment, it is simply required to apply the pumping pressure to the palm then an inflatable bag 1' need only be provided in the region of the palm and the wrap dimensioned accordingly, as is indicated in Fig Fig 5 furthermore displays the provision of a pair of a pair of tabs 12, 12' on the left hand lobe 10. This enables selective tensioning of the wrap and ensures in particular a better fit around the base of the fingers by tensioning the upper of the two tabs 12'.

In the embodiment shown in Fig 6, the left hand lobe 10 of the hand wrap is provided with an extension strapping 10' at the outermost end of which the tab 12 is attached.

The underside of the lobe 9 is provided with a loop 16, more clearly shown in Figs 6b and 6c.

As with the Fig 5 embodiment, the inflatable bladder 1' fits into the palm of the hand. The strapping 10' may either be threaded through the loop 16 when the hand for treatment is laid on the wrap, or it can be passed through the loop 16 before sliding the hand inside the wrap.

Pulling on the strapping then provides single handed tensioning of the wrap which is clearly an advantage for persons with a hand disability.

WO 96/32085 PCT/GB96/00839 After tensioning, the strapping 10' is folded back upon itself and the tab 12 is attached as by Velcro to the main body of the lobe 10 as shown in Fig 6c. The downwardly extended lobe 11 is folded as before around the base portion of the hand and thumb and fastened to the lobe With a single palm engaging inflatable bladder as shown in Figs 5 and 6, the rear of the hand becomes subjected to squeezing forces due to the circumferential nature of the outer wrap, that is through the shrinking of the lo volume within the wrap, although the inflation in the palm will act to clench the hand into a fist which is the natural mode of action by which blood is pumped from the hand.

Although not shown in the embodiments described above, the hand wrap may be provided with a pouch in the region of the palm of the hand into which a thin stiffener can be inserted if so desired.

This has the effect of maximising the impulsive pulse delivered to the hand and prevents dissipation of energy.

Having regard to the aforementioned inflation/deflation regime, the therapeutic results obtained after use of the inflatable wrap depend very much on the parameters of the inflation and deflation of the bag.

Where the enhancement of venous return flow is paramount the wrap should be inflated to maximum operational pressure as quickly as possible, typically within two seconds, to imitate the speed with which involved veins are compressionally squeezed in a quick clenching of the fist. Such fast inflation imparts a jerk or sharply pulsed action in return-blood flow, and such action is believed to be helpful in reducing swelling and pain. It is believed that maximum velocity, however transient upon pulsed excitation, is more important than total blood flow. The veins have check-valve formations, and the downstream side of each check-valve is a trap-like situs for undesired accumulation of solids or clotting which may not otherwise be flushed through the venous-return system; it is believed that with bag inflation as rapid as possible, the opening phase for each check valve is correspondingly rapid, thus WO 96/32085 PCT/GB96/00839 9 locally stirring trapped return-flow blood and reducing the chances of a clotting constriction of return-flow passages.

The pressure may be released virtually instantaneously after the peak pressure has been achieved, typically in approximately 1 second to minimise patient discomfort, or it may be held on for typically up to 4 seconds where maximal hyperaemia and arterial inflow is desired. After the pressure has been released, a period is allowed for the refilling of the veins prior to the application of the next pressure cycle and this may typically be between 5 and 30 seconds.

The peak pressure P for any delivered inflation impulse should be that which is sufficient to produce the appropriate venous impulse, typically between 50 and 300 mm of Hg, whilst not being too uncomfortable for the patient to tolerate.

This will, of course, mean a peak pressure P which will vary, depending upon the particular patient and his affliction.

Furthermore, the walls of the vessels produce EDRF (Endothelial-derived relaxing factor, believed to be nitrous oxide) in response to shear stress produced by changes of blood flow. The EDRF so released plays a role both in powerfully relaxing vessel wall muscle thereby allowing increase blood flow and desegregating platelets further helping to explain how such impulse pumping is effective in preventing, for example, venous thrombosis. It is believed that the maximal shear stress is achieved by the maximal acceleration from the surge of blood as a result of the applied pumping pressure.

For arterial flow enhancement however if, following the inflation the local compression is held for a period of typically up to five seconds, a therapeutically beneficial result is achieved in arm-artery afflictions which involve ischaemia from various causes that have produced arterial obstruction in an extremity.

The effect is maximised for any given patient by selecting the maximum pressure P which the particular patient can comfortably tolerate.

Claims (13)

1. A medical device for applying a venous or arterial blood flow enhancement pumping pressure to a human hand comprising an inflatable sealed enclosure for engagement with a human hand and means for selective admission of inflation pressure fluid into the enclosure to apply said pumping pressure including by means for securing the enclosure to a human hand to form an inflatable wrap, said securing means having first and second interconnectable securing lobes defining a peripheral extent including a thumb insert in its peripheral contour, and a third securing lobe connectable to either the first or second securing lobes or to itself around the wrist whereby the wrap may be secured around a human hand with the distal ends of the fingers extending from the wrap such that upon inflation of the enclosure a squeezing action is applied to promote venous or arterial blood flow.

2. A medical device according to claim 1 wherein the inflatable sealed enclosure is :.:.:adapted substantially circumferentially to enclose a human hand.

3. A medical device according to claim 1 wherein the inflatable sealed enclosure is Sadapted substantially to engage only the palm of a human hand.

4. A medical device according to one of claims 1 to 3 wherein the first and second lobes are connectable to each other by means of providing one lobe with a tab which engages the outer surface of the other lobe to permit adjustable attachment thereto.

5. A medical device according to any one of claims 1 to 3 wherein the two lobes are connected to each other by a means of providing one lobe with an elongate strap which can be threaded through a loop provided on the outer surface of the other lobe and then back upon itself for engagement with the outer surface of said one lobe, thereby to ••.permit selective tensioning of the wrap around the hand.

6. A medical device according to claim 4 wherein said one lobe is provided with one or more further tabs for adjustable attachment to the other lobe.

7. A medical device according to any one of claim 1 to 6 wherein the third lobe is adjustably attached to one or both of the first and second lobes by means of providing the third lobe with a tab which engages the outer surface of the respective lobes to allow S, adjustable attachment. 13 i~ -11

8. A medical device according to any preceding claim wherein the sealed enclosure is a bag fastened to a backing material having a peripheral extent in excess of that of the bag, the contours of the backing material and bag including a U-shaped indent formed adjacent to one of the first and second lobes to provide said thumb insert.

9. A medical device as claimed in any preceding claim wherein the wrap is provided with a pouch, a stiffener inserted in the pouch whereby to maximise the impulse delivered to the hand during pumping of the inflatable sealed enclosure.

A medical device as claimed in any preceding claim including means for cyclically inflating the sealed enclosure between a peak operating pressure achieved within 2 seconds and a minimum operating deflation pressure achieved within 5-30 seconds of the peak pressure.

11. A medical device as claimed in claim 10 wherein the peak operating pressure is held for up to 5 seconds before release.

12. A medical device as claimed in claim 11 wherein the peak pressure is between 15 to 300nmmHg.

13. A medical device substantially as hereinbefore described with reference to and as S illustrated in the accompanying drawings. DATED this 22nd Day of March, 2000 NOVAMEDIX DISTRIBUTION LIMITED Attorney: JOHN D. FORSTER S: Fellow Institute of Patent and Trade Mark Attorneys of Australia .o Of BALDWIN SHELSTON WATERS *C a o 7-A* ZL77