A MEDICAL DEVICE FOR THE HAND

Abstract: An inflatable wrap for promoting venous or arterial blood flow enhancement in the human hand. The wrap comprises an inflatable bag fastened to a backing material. The bag is shaped to fit against the palm of the hand and portions of the back of the hand. The backing material comprises a base portion substantially corresponding to the palm of the hand and two or more interengageable lobes that may be fastened together across the back of the hand to retain the inflatable bag securely against the hand such that upon inflation of the bag a pumping pressure is applied positively to the hand to promote the venous or arterial flow enhancement.

Description: - 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 mitten-like 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 die 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 me medical practitioner and painful from the point 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, bo in terms of normal variation and degree of swelling. SUMMARY OF THE INVENTION It is accordingly an object of this invention to provide a medical appliance that will 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. According to the invention there is provided 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 the hand and means for selective admission of inflation pressure fluid into the enclosure to apply the pumping pressure to the hand, characterised by means for securing the enclosure to the hand to form an inflatable wrap for enveloping the hand with the fingers and thumb extending separately from the wrap, said securing means having two lobes which are connectable to each other and which act to retain the wrap on the hand such that on inflation of the enclosure, a squeezing action is applied to promote venous or arterial blood flow. The medical device so provided overcomes the disadvantages of the prior art since it 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 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. 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 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; and Fig 6 is a schematic view 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 witii 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 appropriate airtightness characteristics which may or may not include ventilation holes (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 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 index finger of the hand as illustrated in Fig 2. A right-hand lobe 9 is defined to the right of tiiis 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 die 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 die outer material for further patient comfort. All die above layers may be laminated together or joined to one another along their respective perimeters. The left-hand lobe 10 of me outer material layer 7 and the downwardly extending lobe 1 1 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, die affected hand is first placed over die device as is indicated in Fig 2 with the respective indentations 2, 8 seated against die portion of me hand between die thumb and d e first finger, such that die tiuimb of the affected hand passes underneatii the right-hand lobe 9 of die outer material layer 7. The right-hand lobe 9 is folded around the affected hand in die direction of die arrow I, folding substantially along die neck of the lobe 9 thereby guiding the right-hand lobe 3 of die inflatable bag 1 as it moves. The right-hand lobe 3 of 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 die 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 d e arrow π guiding die 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 die greater lateral extent of die right and left hand lobes 9, 10 of the outer material layer 7 tiiese respective lobes 9, 10 will now overlap one anotiier. Thus die left-hand lobe 10 of the outer material layer 7 may be secured to die underlying right hand lobe 9 of die outer material layer 7, typically by means of die engagement of die tab 12 witii die looped surface of the right-hand lobe 9. The longitudinally downwardly extended lobe 11 is folded around die base portion of the hand and tiiumb in die direction of the arrow III, thereby extending diagonally across boti the left and right-hand outer material layer lobes 9, 10 whereupon it may be fastened to die outer surface of die left-hand lobe 10, as shown in Fig 3, again typically by means of engagement of the tab 13 with the looped surface of die outer material layer 7. onsequendy, die affected hand is substantially circumferentially enclosed by the inflatable bag 1 which is secured thereto by means of die interengageable lobes 9, 10, 11. Since the lobes 9, 10, 1 1 are typically fastened by means of engagement of a tab 12, 13 witii a looped surface, d e inflatable wrap may easily be adjusted to fit a wide range of sizes of hand. Witii the interengagement of the respective three outer material layer lobes 9, 10, 11, me inflatable wrap effectively encompasses the portion of die hand required to be squeezed whilst allowing free and constant inspection of die fingers and thumb of the affected hand during treatment in respect of, for 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 die device and tethered around die wrist to itself by means of a tab 15 is used in place of the third lobe 11 to effect the adjustable securing of die inflatable wrap to the hand. Furthermore, in place of die overlap of the respective lobes 9, 10 allowing the interengagement described above, any other suitable means to effect die secure connection of die lobes 9, 10 may be used. Iξ having regard to a third embodiment, it is simply required to apply die pumping pressure to the palm then an inflatable bag 1' need only be provided in die region of the palm and the wrap dimensioned accordingly, as is indicated in Fig 5. Fig 5 furthermore displays the provision of a pair of a pair of tabs 12, 12' on die left hand lobe 10. This enables selective tensioning of the wrap and ensures in particular a better fit around die base of the fingers by tensioning the upper of the two tabs 12'. In die embodiment shown in Fig 6, the left hand lobe 10 of the hand wrap is provided with an extension strapping 10' at die outermost end of which the tab 12 is attached. The underside of die lobe 9 is provided with a loop 16, more clearly shown in Figs 6b and 6c. As with die Fig 5 embodiment, the inflatable bladder 1' fits into the palm of the hand. The strapping 10 * may either be threaded through die loop 16 when the hand for treatment is laid on die wrap, or it can be passed through the loop 16 before sliding the hand inside die wrap. Pulling on die strapping then provides single handed tensioning of the wrap which is clearly an advantage for persons with a hand disability. After tensioning, the strapping 10' is folded back upon itself and die tab 12 is attached as by Velcro to die main body of die lobe 10 as shown in Fig 6c. The downwardly extended lobe 11 is folded as before around die base portion of die hand and thumb and fastened to die lobe 10. With a single palm engaging inflatable bladder 1', as shown in Figs 5 and 6, the rear of the hand becomes subjected to squeezing forces due to die c cumferential nature of die outer wrap, mat is through die shrinking of die volume witiύh the wrap, aldiough die inflation in die palm will act to clench die hand into a fist which is the natural mode of action by which blood is pumped from die hand. Although not shown in die embodiments described above, die hand wrap may be provided witii a pouch in the region of die palm of die hand into which a tiϋn stiffener can be inserted if so desired. This has die effect of maximising die impulsive pulse delivered to die hand and prevents dissipation of energy. Having regard to the aforementioned inflation/deflation regime, die dierapeutic results obtained after use of die inflatable wrap depend very much on the parameters of die inflation and deflation of the bag. Where die enhancement of venous return flow is paramount die wrap should be inflated to maximum operational pressure as quickly as possible, typically witi-in two seconds, to imitate die speed witii which involved veins are compressionally squeezed in a quick clenching of die 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 tiian total blood flow. The veins have check-valve formations, and die 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 die venous-return system; it is believed tiiat witii bag inflation as rapid as possible, die opening phase for each check valve is correspondingly rapid, thus 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 d e 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 die veins prior to the application of die next pressure cycle and this may typically be between 5 and 30 seconds. The peak pressure P for any delivered inflation impulse should be tiiat 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, die 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 die surge of blood as a result of die 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 die maximum pressure P which die particular patient can comfortably tolerate.

Claims: CLAIMS 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 witii die hand and means for selective admission of inflation pressure fluid into the enclosure to apply the pumping pressure to die hand, characterised by means for securing die enclosure to die hand to form an inflatable wrap for enveloping die hand with die fingers and tiiumb extending separately from the wrap, said securing means having two lobes which are connectable to each other and which act to retain the wrap on die hand such that on inflation of die enclosure, a squeezing action is applied to promote venous or arterial blood flow. 2. A medical device according to claim 1 characterised in that in die retained position die inflatable sealed enclosure substantially circumferentially encloses die hand. 3. A medical device according to claim 1 characterised in that in the retained position die inflatable sealed enclosure substantially engages only die palm of die hand. 4. A medical device according to one of claims 1 to 3 characterised in that die two lobes are connectable to each other by means of providing one lobe with a tab which engages die outer surface of the odier lobe to permit adjustable attachment tiiereto. 5. A medical device according to any one of claims 1 to 3 characterised in tiiat the two lobes are connected to each otiier by a means of providing one lobe with an elongate strap which can be tiireaded through a loop provided on the outer surface of die otiier lobe and tiien back upon itself for engagement with die outer surface of said one lobe, ti ereby to permit selective tensioning of die wrap around die hand. 6. A medical device according to claim 4 characterised in mat said one lobe is provided with one or more further tabs for adjustable attachment to die other lobe. 7. A medical device according to one of claims 1 to 6 characterised in that the securing means includes a third lobe for adjustable attachment around die base of the thumb of die hand to one or both of the first and second lobes. 8. A medical device according to claim 7 characterised in that die third lobe is adjustably attached to one or both of die first and second lobes by means of providing the third lobe with a tab which engages die outer surface of the respective lobes to allow adjustable attachment. 9. A medical device according to one of claims 1 to 6 characterised in that the securing means includes a strap for securable attachment around the wrist. 10. A medical device according to any preceding claim wherein die sealed enclosure is a bag fastened to a backing material having a peripheral extent in excess of that of the bag, die contours of die backing material and bag including a U-shaped indent formed adjacent to one of the first and second lobes to provide a thumb insert. 11. A medical device as claimed in any preceding claim wherein a pouch is provided for accepting a stiffher whereby to maximise the impulse delivered to the hand during pumping of the inflatable sealed enclosure. 12. 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 witiiin 5-30 seconds of the peak pressure. 13. A medical device as claimed in claim 12 wherein the peak operating pressure is held for up to 5 seconds before release. 14. A medical device as claimed in claim 13 wherein the peak pressure is between 50 to 300 mmHg. 15. A medical device substantially as hereinbefore described with reference to and as illustrated in die accompanying drawings.

Inventors: BROWN IAN GRAHAM, COOK GORDON JOHN, GREGORY PAUL GERARD, BROWN, IAN, GRAHAM, COOK, GORDON, JOHN, GREGORY, PAUL, GERARD
Applicants: BROWN IAN GRAHAM, COOK GORDON JOHN, GREGORY PAUL GERARD, NOVAMEDIX DISTRIBUTION LIMITED, BROWN, IAN, GRAHAM, COOK, GORDON, JOHN, GREGORY, PAUL, GERARD
Application year: 1996
Main classification: A61H9
IPC codes: A61H7, A61H9, A61H23