GB1599607A

GB1599607A - Device for applying presure to a patients limb

Info

Publication number: GB1599607A
Application number: GB13792/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-04-07
Filing date: 1978-04-07
Publication date: 1981-10-07
Also published as: JPS53126787A; CA1079146A; FR2386304A1; FR2386304B1; SE7803943L; IT7822027A0; DE2814691A1; IT1095103B

Description

(54) DEVICE FOR APPLYING PRESSURE TO A PATIENT'S LIMB (71) I, JOHN KIMBALL WHITNEY, a citizen of the United States of America of P.O. Box 19, Dorado Beach, Puerto Rico 00646, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to apparatus for the alleviation of deep venous thrombosis by mechanical means.

Deep venous thrombosis is a condition in which clotting of venous blood occurs in the lower extremities and pelvis because of the lack of sufficient muscular activity in the lower legs. Such clotting can be life threatening if a bloold clot migrates to the heart, lung or brain and interferes with blood circulation.

Preventive treatment often employs chemical means, such as anticoagulants; however, such chemical means are often contra-indicated for example, in neurological surgery or where the threat of haemorrhage is present.

In these latter conditions the prevention of deep venous thrombosis has been attempted by mechanical means employing elastic bandages or stockings or by pneumatic leggings adapted to receive a pressured gas in desired sequence. U.S. Patent No. 3,892,229 illustrates one form of this type of device and U.S. Patent No. 3,901,221 illustrates a type of pressured sequence.

While devices such as those shown in U.S.

Patent 3,892,229 have been employed successfully, it is believed that problems exist therewith. Such problems arise from the fact that pressure is applied equally and simultaneously throughout the entire limb. It is more preferable to force the blood in the extremities back toward the heart. Devices which apply a uniform overall pressure do not move the blood in a specific direction.

Furthermore, these devices are made from rubber or plastics material and are quite hot when worn for long periods of time and no means for providing ventilation exist.

It is, therefore, an object of this invention to provide an alternative apparatus for alleviating deep venous thrombosis, which tends to push blood back towards the heart and which includes means for ventilating the area between the device and the limb.

According to the present invention there is provided an apparatus for the alleviation of operative and post operative deep venous thrombosis, which apparatus comprises a flexible pad having a first plurality of inflatable cells adapted to apply pressure to a mammalian limb when inflated by a fluid, a second plurality of smaller, inflatable cells arrayed alternately with the first plurality of cells, the second plurality of cells being adapted to receive and discharge a supply of ventilating fluid, and means for supplying fluid to the cells; the pad being capable of enwrapment about a mammalian limb with the cells generally perpendicular to the longitudinal axis of the limb.

The apparatus preferably also includes means for exhausting the inflating fluid, for example, means for directing fluid from the first plurality of cells to the second plurality of cells.

In use, the cells of the pad are pressurized sequentially, beginning with the distal cell which encircles, for example, the ankle area of a human leg. An adjacent cell is then pressurized and then another until all cells are pressurized. The entire sequence takes about 10 seconds, and then the cells are all simultaneously depressurized and no pressure is applied for approximately one minute. In a preferred embodiment, the pressure izing fluid is a non-toxic gas, for example air, and during the depressurized period the gaseous fluid is applied to the ventilating cells for supplying ventilation to the area between the pad and the skin.

This apparatus seems to be an improvement over prior art devices in the sequential application of pressure, which will tend to push venous blood collecting in the limb back towards the heart, and in the ventilation provided during periods of no pressure.

The invention will now be illustrated with reference to the following partly diagrammatic drawings, in which Figure 1 is a plan view of one form of the apparatus of the invention showing a flexible pad comprising a plurality of pressure applying cells and supply hoses with some parts broken away and some parts omitted; Figure 2 is a sectional view of the pad taken along the line 2-2 of Figure 1; Figure 3 is a partial, idealized view drawn to a larger scale than Figures 1 & 2 illustrating the manner of sealing a fluid-carrying hose into a cell of the pad; Figure 4 is a diagrammatic view of the fluid supply and distribution system to pad of the Figures 1 and 2; Figure 5-9 and 11 are schematic representations of the valving system showing the pressurization, exhaust and ventilation sequences for the pad of Figures 1 and 2;; Figure 10 is a graphic chart ofthe pressurization, exhaust and ventilation sequences and times for the pad of Figures 1 and 2; and Figures 12 and 13 are schematic representations of an alternative valving system and operating sequence to that shown in Figures 5 to 9 and 11.

Referring now to the drawings with greater particularity, there is shown in Figure 1 an apparatus 20 for the alleviation of operative and post operative deep venous thrombosis.

Apparatus 20 comprises a flexible pad 22 formed for enwrappment about a mammalian limb, such as a human leg. The pad 22 is formed from two overlying sheets 24, 26 (Fig.

2) of a fluid impervious material such as rubber, polyethylene or a vinyl plastics. A first plurality of cells numbered lc, 2c 3c and 4c is formed within pad 22 by means of dielectric welding or similar heat sealing techniques or a connecting technique so that each cell is a separate entity. The sealed areas are shown diagrammatically at 28 in Figure 2. Each of the cells lc, 2c, 3c and 4c is relatively large.

A second plurality of relatively smaller cells, numbered lv, 2v and 3v, is also provided within the pad 22, the second plurality of cells being arrayed alternately with the first plurality, cell lv lying between larger cells lc and 2c, cell 2v lying between cells 2c and 3c, and cell 3v lying between larger cells 3c and 4c, though the smaller cells only extend for about half of the length of the adjacent larger cells. Each of the cells of the second plurality is provided with a multiplicity of small apertures 30 for releasing a ventilating fluid, as will be explained hereinafter.

While each of the cells Ic to 4c of the first plurality of cells may be of identical length, in the preferred embodiment illustrated in Figure 1 the cells are of varying lengths to accommodate the varying circumferences of, for example, a human leg. Thus, in Figure 1, cell lc has a shorter length for enwrappment about the ankle - area, while cells 3c and 4c are longer to accommodate the greater circumference of the calf. As will also be apparent from Figure 1, the length of each of the cells is greater than its width.

One end of each of the cells lc-4e is formed to receive pressurised fluid, which is in the form of a non-explosive non-toxic gas, preferably air. Each of the cells lc, 2c, 3c and 4e is fluidly independent from the remaining cells and is provided with a fluid inlet and outlet means labeled lf 2f 3f and yrespec- tively, in the form of a hose which has one of its ends sealed into the cell and the other end connected to a distributor 32 (Fig. 4).

The hoses are sealed into the cells in a manner illustrated diagrammatically and ideally in Figure 3. Therein, it will be seen that a hose, for example of is heat sealed as at 34 or cemented between the two layers 24 and 28. The heat sealed area 34 blends into the peripheral seal area 36.

The cells lc4c are physically connected together for about half of their lengths and are formed as physically separated entities for the other half of their lengths. This is accomplished as can be seen in Figure 1, by forming (a) cuts 38 between the heat sealed areas separating the cells. This separation also aids in wrapping the pad 22 about the varying circumferences of a human leg.

Fastening means 40 are also provided for maintaining the pad 22 in position on the leg and can comprise any suitable means such as Velcro (Trade mark) fasteners, a belt and buckle arrangement, tie-together tapes, or a piece of adhesive tape.

The underside or- patient side of pad 22 shown uppermost in Figures 1 and 2 is provided with cushioning material 42 such as foam rubber or a non-woven cloth or similar material. A cellular type material is preferred to aid in the ventilation cycle to be described.

As mentioned above, the large cells lc-4c are each independent with respect to the pressurizing fluid; however, the second plurality of cells lv-3v are all commonly connected together through an exhaust manifold 44, with which the cells lv-3v communicate.

The exhaust manifold 44 in turn is fed by a hose 46 from distributor 32.

In referring now to Figs. 4-9 and specifically to Fig. 4 there is shown fluid pressure supply means 45 which comprises a source of fluid pressure 47 (labelled fluid supply) such as an air pump, which feeds distributor 32 which sequentially feeds pressure cells lc-4c and ventilating cells lv-3v.

In the diagrammatic representations of Figs. 5-8 the sequential operation is shown as being controlled by a plurality of valves.

Thus, at the beginning of a cycle, valve 48 in fluid supply 47 is open as is valve 50 in hose If which feeds cell lc. The remaining valves 52, 54, 56 and 58 of distributor 32, are closed allowing only cell lc to fill. After a suitable time has elapsed and a suitable pressure has been reached within the cell (about 4 seconds and about 40 mmHg) valve 50 closes and valve 52 opens (Fig. 6). With valve 52 open cell 2c is filled. Next, cell 3c is filled (Fig. 7) and finally cell 4c (Fig. 8).

The graph of Fig. 10 illustrates the filling cycle and it can be seen therefrom that all of the four cells lc to 4c are filled in approximately 16 seconds, all four cells are held at pressure for about four additional seconds and then simultaneously dumped or exhausted. The exhaust position of the valves is shown in Fig. 9 whereat supply valve 48 closes and valves 50, 52, 54, 56 and 58 open.

In this circumstance the pressured air from cells lc-4c flows back through distributor 32, through valve 58 through hose 46 to exhaust manifold 44 and thence to ventilating cells 1 v, 2v and 3v whereat the air is vented through pin hole apertures 30 to ventilate the area between the pad 22 and the patient. As seen from the graph, Figure 10, the dumping or exhaust takes about 2 seconds. Further ventilation for the entire down time of the cells is then provided by closing valves 50, 52, 54 and 56 and opening supply valve 48 while keeping valve 58 open (Fig. 11). This allows air to be pumped continuously from the supply means through exhaust manifold 44 and cells 1 v-3v from where it escapes through apertures 30 until the cycle is ready to be repeated.A complete cycle of pressun- zation, exhaust and ventilation takes approximately one and one half minutes. At the end of such a 90 second cycle the pressurization begins again, as shown in Fig. 10.

The above described procedure for supplying ventilation is the preferred one since it is eminently workable and inexpensive; however, for providing continuous ventilation a dual supply could be provided and the pressurized cells could be fed thereinto or exhausted to atmosphere. Such an alternative is shown in system Figs. 12 and 13.

Referring specifically to Fig. 12, there is shown a system at its final stage of filling.

The cells have been filled sequentially, but the individual fill valves 50, 52 etc. have been left open as their respective cells have been filled. This keeps a constant supply of pressure thereinto. An additional exhaust valve 60 is provided and is vented to atmosphere.

Further, the fluid supply 47 is distributed between cell filling valve 48 and ventilating valve 62. As illustrated in Fig. 12 valve 48 is open as are valves 50, 52, 54 and 56. At the end of the filling cycle valve 48 closes and valves 60 and 62 open (Fig. 13). This allows the cells lc, 2c, 3c and 4c to vent to atmosphere directly through valve 60 without exhausting through the ventilating cells.

Ventilation is supplied directly to the ventilating cells via fluid supply 47 and open valve 62. This system is preferred when the pressure in the cells lc, 2c, 3c and 4c may not be sufficiently high to totally exhaust through the ventilating cells.

The pad and system herein provided achieves great success in the alleviation of operative and post operative deep venous thrombosis. The sequential filling of the cells from the ankle upward toward the calf has a massaging or squeezing effect upon the veins which increases venous blood flow towards the heart much better than systems which supply pressure over the entire lower leg.

It should also be noted that while the system has been described herein as relating to a cuff which encompasses a lower leg, there is no reason why the cuff could not be made large enough to cover the leg from ankle to groin.

While there has been shown and described what are at present considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that varous changes and modifications can be made herein without departing from the scope of the invention as defined by the appended claims.

WHAT I CLAIM IS: 1. An apparatus for the alleviation of operative and post operative deep venous thrombosis, which apparatus comprises a flexible pad having a first plurality of inflatable cells adapted to apply pressure to a mammalian limb when inflated by a fluid, a second plurality of smaller, inflatable cells arrayed alternately with the first plurality of cells, the second plurality of cells being adapted to receive and discharge a supply of ventilating fluid, and means for supplying fluid to the cells; the pad being capable of enwrapment about a mammalian linpb with the cells generally perpendicular to the longitudinal axis of the limb.

2. An apparatus as claimed in claim 1, wherein the respective lengths of the first plurality of cells are such that the pad can accommodate the various circumferences of the mammalian limb.

3. An apparatus as claimed in claim 1 or 2, wherein each cell of the first plurality of cells has a first end formed to receive inflating fluid.

4. An apparatus as claimed in any one of the preceding claims wherein adjacent cells of the first plurality of cells are joined together for about one half their length.

5. An apparatus as claimed in any one of the preceding claims in combination with

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Figs. 5-8 the sequential operation is shown as being controlled by a plurality of valves. Thus, at the beginning of a cycle, valve 48 in fluid supply 47 is open as is valve 50 in hose If which feeds cell lc. The remaining valves 52, 54, 56 and 58 of distributor 32, are closed allowing only cell lc to fill. After a suitable time has elapsed and a suitable pressure has been reached within the cell (about 4 seconds and about 40 mmHg) valve 50 closes and valve 52 opens (Fig. 6). With valve 52 open cell 2c is filled. Next, cell 3c is filled (Fig. 7) and finally cell 4c (Fig. 8). The graph of Fig. 10 illustrates the filling cycle and it can be seen therefrom that all of the four cells lc to 4c are filled in approximately 16 seconds, all four cells are held at pressure for about four additional seconds and then simultaneously dumped or exhausted. The exhaust position of the valves is shown in Fig. 9 whereat supply valve 48 closes and valves 50, 52, 54, 56 and 58 open. In this circumstance the pressured air from cells lc-4c flows back through distributor 32, through valve 58 through hose 46 to exhaust manifold 44 and thence to ventilating cells 1 v, 2v and 3v whereat the air is vented through pin hole apertures 30 to ventilate the area between the pad 22 and the patient. As seen from the graph, Figure 10, the dumping or exhaust takes about 2 seconds. Further ventilation for the entire down time of the cells is then provided by closing valves 50, 52, 54 and 56 and opening supply valve 48 while keeping valve 58 open (Fig. 11). This allows air to be pumped continuously from the supply means through exhaust manifold 44 and cells 1 v-3v from where it escapes through apertures 30 until the cycle is ready to be repeated.A complete cycle of pressun- zation, exhaust and ventilation takes approximately one and one half minutes. At the end of such a 90 second cycle the pressurization begins again, as shown in Fig. 10. The above described procedure for supplying ventilation is the preferred one since it is eminently workable and inexpensive; however, for providing continuous ventilation a dual supply could be provided and the pressurized cells could be fed thereinto or exhausted to atmosphere. Such an alternative is shown in system Figs. 12 and 13. Referring specifically to Fig. 12, there is shown a system at its final stage of filling. The cells have been filled sequentially, but the individual fill valves 50, 52 etc. have been left open as their respective cells have been filled. This keeps a constant supply of pressure thereinto. An additional exhaust valve 60 is provided and is vented to atmosphere. Further, the fluid supply 47 is distributed between cell filling valve 48 and ventilating valve 62. As illustrated in Fig. 12 valve 48 is open as are valves 50, 52, 54 and 56. At the end of the filling cycle valve 48 closes and valves 60 and 62 open (Fig. 13). This allows the cells lc, 2c, 3c and 4c to vent to atmosphere directly through valve 60 without exhausting through the ventilating cells. Ventilation is supplied directly to the ventilating cells via fluid supply 47 and open valve 62. This system is preferred when the pressure in the cells lc, 2c, 3c and 4c may not be sufficiently high to totally exhaust through the ventilating cells. The pad and system herein provided achieves great success in the alleviation of operative and post operative deep venous thrombosis. The sequential filling of the cells from the ankle upward toward the calf has a massaging or squeezing effect upon the veins which increases venous blood flow towards the heart much better than systems which supply pressure over the entire lower leg. It should also be noted that while the system has been described herein as relating to a cuff which encompasses a lower leg, there is no reason why the cuff could not be made large enough to cover the leg from ankle to groin. While there has been shown and described what are at present considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that varous changes and modifications can be made herein without departing from the scope of the invention as defined by the appended claims. WHAT I CLAIM IS:

1. An apparatus for the alleviation of operative and post operative deep venous thrombosis, which apparatus comprises a flexible pad having a first plurality of inflatable cells adapted to apply pressure to a mammalian limb when inflated by a fluid, a second plurality of smaller, inflatable cells arrayed alternately with the first plurality of cells, the second plurality of cells being adapted to receive and discharge a supply of ventilating fluid, and means for supplying fluid to the cells; the pad being capable of enwrapment about a mammalian linpb with the cells generally perpendicular to the longitudinal axis of the limb.

valving means whereby fluid is supplied to the first plurality of cells in a predetermined sequence.

6. An apparatus as claimed in claim 5, wherein the valving means is arranged such that individual cells of the first plurality of cells are inflated sequentially beginning with the distal cell, and all of the cells exhaused simultaneously.

7. An apparatus as claimed in any one of the preceding claims, which apparatus includes means for exhausting the inflating fluid.

8. An apparatus as claimed in claim 7 wherein means for exhausting the inflating fluid includes means for directing fluid exhausted from the first plurality of cells to the second plurality of cells.

9. An apparatus as claimed in any one of the preceding claims wherein the pad is formed from two overlying sheets of fluid impervious material.

10. An apparatus as claimed in claim 9 wherein the individual cells are formed in the sheets by means of dielectric welds.

11. An apparatus as claimed in any one of the preceding claims wherein said pad is provided with a fastening means for retaining the pad in wrapped position on the mammalian limb.

12. An apparatus as claimed in Claim 7 suitable for operation with a pressurized gas wherein the second plurality of cells is provided with means for feeding the exhaust gas to the region between the pad and the limb when the pad is in use, in order to provide ventilation.

13. An apparatus as claimed in claim 12 wherein the side of the second plurality of cells facing the limb is provided with a multiplicity of pin hole apertures.

14. An apparatus for the alleviation of deep venous thrombosis substantially as hereinbefore described and illustrated with reference to figures 1 to 3.

15 .An apparatus as claimed in claim 14 arranged to operate substantially as hereinbefore described and illustrated with reference to figures 4 to 11.

16. An apparatus as claimed in claim 14 arranged to operate substantially as hereinbefore described and illustrated in reference to figures 4, 10, 12 and 13.