PORTABLE SEQUENTIAL COMPRESSION DEVICE

Abstract: A sequential compression device for delivering pressurized air to a multi-compartment inflatable sleeve on a patient's limb. The device includes a pump, a plurality of cam actuated valves and a plura­ lity of conduits in communication with said valves, all disposed within an accumulator, which comprises the housing for the device as well.

Description: This invention relates to therapeutic and prophylactic devices, and more particularly to devices for applying compressive pressures against a patient's limb. Velocity of the flow of blood in patient's arms and legs particularly the legs, markedly decreases during the term of confinement of the patient. This slow-down in the velocity of blood in those extremities causes a cooling or stasis of blood which is particularly pronounced during surgery, immediately after surgery, and when the patient has been confined to bed for extended periods of time. The stasis of blood is a significant cause of the formation of thrombi in the patient's extremities, which would have a severe deleterious effect on the patient. Additionally, in certain patients, it is desirable to move fluid out of enterstital spaces in the tissues of their extremities, in order to reduce swelling associated with edema in those extremities. U.S. Patent 4,013,069 to Hasty, discloses a sequential intermittent compression device for applying compressive pressures against a patient's limb, from a source of pressurized fluid. U.S. Patent 4,338,923 shows an inflatable-cell body treating apparatus having a compressor attached to a receiver which directs the compressed air through a reduction valve then to an inlet port of a rotary distributor, eventually to an inflatable band. U.S. Patent 3,862,629 shows a fluid pressure control apparatus including a complicated oscillatory valve arranged from a supply system to an exhaust, which feeds a plurality of inflatable chambers disposed about a patient's limb. U.S. Patent 2,528,843 discloses an intermittent pressure generator comprising a piston-cylinder arrangement with a plurality of take-off tubes in communication with the cylinder, to supply pressurized fluid to a sleeve. US-A-3,465,749 discloses a rotating tourniquet device comprising a pump, a pressure reservoir and a plurality of valves and conduits with the pump, the valves and the conduits being external of the pressure reservoir. Some of the prior art compressive devices are expensive to manufacture, are complicated and cumbersome, and inconvenient to use, particularly in a home care environment, where sophisticated technical help is not readily available. It is an object of the present invention to provide an intermittent compressive device for sequentially generating fluid pressures and providing such compressive fluid to a sleeve adapted to be located about a patient's limb. It is a further object of the present invention to provide a small, self-contained compressive device that is easy to use and carry, with minimum inconvenience. The present invention is concerned with a sequential compression device for supplying pressure sequentially to an inflatable elongated sleeve which is utilized to pressurize a patient's limb. The sequential compression device comprises a housing having an upper housing portion and a lower housing portion. The upper and lower housings define an accumulator. The accumulator directs pulses of pressurized air through a plurality of conduits, to the inflatable sleeve. The lower housing has a generally flat lower surface and is surrounded on its periphery by four upstanding walls having a common planar uppermost edge. A vacuum pump is secured to the lower surface of the lower housing and has an intake line in fluid communication with an orifice in a wall of the lower housing. The vacuum pump has a discharge orifice on the pump housing which discharges pressurized air directly into the housing, that is, the accumulator. An electric motor is attached to and provides rotational impetus for the pump. An exhaust manifold is disposed in the accumulator, adjacent the pump. The manifold has a plurality of conduits, having their proximal ends open to the atmosphere in the accumulator. The conduits are directed through an upstanding wall and are connected at their distal ends to a discharge manifold in an outer wall in the lower housing. Thus according to the present invention a sequential compression device for delivering sequentially pressurized air, e.g. for medical purposes, to an inflatable device, e.g. a multi-compartment sleeve, comprises: an accumulator for containing pressurized air; a pump to supply pressurized air to the said accumulator; a plurality of conduits each having a proximal open end in the said accumulator and a distal end disposed through a wall of the said accumulator to discharge the said pressurized air from the said accumulator; and a plurality of valves to control the flow of pressurized air into the said conduit from the said accumulator, the said conduits, the said pump and the said valves all being disposed within the said accumulator, to compress the said air therewithin, and to selectively discharge the said pressurized air through the said conduits in the said accumulator, to a discharge orifice or orifices. A plurality of stoppers are pivotably disposed at the proximal ends of the conduits at the exhaust manifold. Each stopper is disposed on the distal end of an arm, which is biased so as to direct each stopper against its respective conduit, at the exhaust manifold. Thus the said valves preferably comprise a manifold having the said conduits arranged with respect to a plurality of stoppers, each of the said stoppers being controlled by a cam arrangement for moving the said stoppers with respect to the proximal end of the said conduits, so as to regulate the pressurized air entering the said conduits. A ganged cam arrangement is disposed parallel to the pivotably disposed stoppers. The ganged cam arrangement is rotatively connected to a small synchronous motor. The cam arrangement controls the movement of the stoppers onto and away from the conduits at the exhaust manifold. A position indicator is attached to each stopper. Each position indicator moves with each stopper, into and out of an optical sensor. The sensor determines the location of its particular position indicator and provides feedback to a proper circuit controlling the cam drive motor and the pump drive motor. An electric motor is preferably arranged to drive the said pump disposed in the said accumulator. The said conduits may be secured to a bracket in the said accumulator, so as to present the said proximal ends to the said valves. The said cam arrangement preferably comprises a plurality of cams each of which have a multiple cam surface and cam followers preferably two e.g. a pair arranged to move each of the said valves with respect to the said open end of the said conduits. The said cam arrangement is preferably rotatively powered by an electric motor. Preferably the said cams are connected to one another, and are angularly arranged with respect to one another so as to effect timed opening and closing of the said conduit openings in the said accumulator. The said accumulator preferably comprises an upper housing and a lower housing, the said lower housing supporting the said pump, motor, and valve arrangement therein, the said upper housing comprising a cover for enclosing the said lower housing. In operation, the pump pressurizes the accumulator, when the upper housing is disposed upon the lower housing, and the proper circuitry is initiated. The proximal ends of the conduits thus receive the pressurized air, pumped into the accumulator from the pump adjacent them, in the accumulator itself. The stoppers governed by their cams, control the flow of pressurized air into the conduits, and hence into any compartmentalized sleeve in communication with the discharge manifold through the housing. A dump valve may be disposed in the said housing, preferably the lower housing, to discharge excess pressure from said accumulator. Preferably said pump has a conduit extending from an orifice in the said housing, preferably the lower housing, to provide an air source therefor. Preferably indicating means are provided for at least one of the said cam followers on each cam, e.g. a position device arranged with a finger disposed with respect to one of the said cam followers on each cam so as to indicate the position of the valve in relation to its respective conduit, to provide feedback for control of the said device. The invention can be put into practice in various ways and one specific embodiment will be described to illustrate the invention with reference to the accompanying drawings, in which: Figure 1 is a side elevational view, partly in section of an accumulator system constructed to the present invention; and Figure 2 is a plan view of the accumulator system shown in Figure 1. Referring now to the drawings in detail, and particularly to Figure 1, there is shown a sequential compression device 10 for supplying pressure sequentially to an inflatable sleeve, such as that shown in U.S. Patent 4,198,961 to Arkans, and assigned to the assignee of the present invention. The sequential compression device 10 comprises a housing 12 having an upper housing portion 14 and a lower housing portion 16. The upper and lower housing portions 14 and 16 define an accumulator 18 capable of containing a volume of about 3 litres of pressurized air at a pressure of at least 5 psi (0,345 bar). The lower housing 16 has a generally flat lower surface 20 and is surrounded on its periphery by four upstanding walls 22, 24, 26 and 28, having a common planar uppermost edge 30. A vacuum pump 32 is secured to the lower surface 20 of the lower housing 16. The pump 32 has an intake conduit 34 which extends through a lip 36 on the rear of the lower housing 16. The conduit 34 supplies the air, which the pump 32 pressurizes, and discharges the air into the accumulator 18 through a discharge port 37. The pump 32 is rotatively driven by an electric motor 38. An exhaust manifold 40 is arranged within the accumulator 18 adjacent the pump 32. The manifold 40 comprises four conduits A, B, C and D having their proximal ends secured within the accumulator 18 by a bracket 42. Each of the conduits A, B, C and D are directed through an upstanding wall 44 and proceed to a discharge manifold 46 in the outer wall 28 in the lower housing 16. The discharge manifold 46 would typically be matingly attached to a plurality of conduits, not shown, for supplying an inflatable sleeve, as described in the above mentioned patent. A ganged cam arrangement 50 is disposed parallel to the exhaust manifold 40, and is rotatively driven by a small synchronous motor 51, as is shown in Figure 2. The cam arrangement 50 comprises four cams C1, C2, C3 and C4. Each cam C1, C2, C3 and C4 has a first and second cam surface 52 and 54. A main cam follower 60 has an extended arm 64 formed therewith. The arm 64 has a stopper 66 which acts as a valve with respect to the proximal (open) end of its respective conduit A, B, C or D. A second cam follower 70 is in registration with the second cam surface 54. The second cam follower 70 has a spring bias means 72 which acts to push the stopper 66 away from the proximal end of its respective conduit A, B, C or D. The arm 64 has a position finger 74 which is displaced, when the stopper 66 is displaced from its conduit A, B, C or D by the spring 72. The finger 74 has a flag 76 on its distal end which engages an optical sensor 78. The optical sensor 78 is in communication with a proper control circuit 80, which provides proper feedback to control the electric motors 38 and 51 running the pump 32 and the cams 50. A dump valve 82 controls any over-pressure, and will shut off the pumps 32 through the proper control circuit 80 if the pressure within the accumulator 18 exceeds a certain level. The air pressure within the accumulator 18 is thus caused to selectively enter the particular conduits A, B, C or D when their respective stopper 66 is displaced therefrom. Each stopper 66 is displaced according to the angular relationship of adjacent cams C1, C2, C3 and C4 in the ganged cam arrangement 50. A delivery conduit, not shown, would be attachable to the discharge manifold 46 to deliver pressurized fluid to an attached sleeve, not shown, to permit sequential pressures to be delivered to that sleeve. The controller in USP 4198961 intermittently supplies air to the inflatable sleeve so as to produce periodic compression cycles and periodic decompression cycles between the compression cycles.

Claims: 1. A sequential compression device (10) for delivering sequentially pressurized air to an inflatable device, comprising: an accumulator (18) for containing pressurized air; a pump (32) to supply pressurized air to the said accumulator; a plurality of conduits (A,B,C,D) and a plurality of valves to control the flow of pressurized air into the said conduits from the said accumulator, characterised in that the said conduits (A,B,C,D), the said pump (32) and the said valves all being disposed within the said accumulator (18), to compress the said air therewithin, and to selectively discharge the said pressurized air through the said conduits in the said accumulator, to a discharge orifice or orifices, and in that each of the conduits has a proximal open end in the said accumulator (18) and a distal end disposed through a wall of the said accumulator (18) to discharge the said pressurized air from the said accumulator. 2. A sequential compression device as claimed in Claim 1, in which the said valves comprise a manifold (40) having the said conduits (A,B,C,D) arranged with respect to a plurality of stoppers (66), each of the said stoppers (66) being controlled by a cam arrangement for moving the said stoppers with respect to the proximal end of the said conduits, so as to regulate the pressurized air entering the said conduits. 3. A sequential compression device as claimed in Claim 1 or Claim 2 in which an electric motor (38) is arranged to drive the said pump (32) disposed in the said accumulator. 4. A sequential compression device as claimed in Claim 1, 2 or 3 in which the said conduits (A,B,C,D) are secured to a bracket (42) in the said accumulator, so as to present the said proximal ends to the said valves. 5. A sequential compression device as claimed in Claim 1, 2, 3 or 4 in which the said cam arrangement comprises a plurality of cams (C1,C2,C3,C4) each of which have a multiple cam surface and cam followers preferably two arranged to move each of the said valves with respect to the said open end of the said conduits. 6. A sequential compression device as claimed in any one of Claims 2 to 5 in which the said cam arrangement is rotatively powered by an electric motor (51). 7. A sequential compression device as claimed in Claim 5 or Claim 6 in which the said cams are connected to one another, and are angularly arranged with respect to one another so as to effect timed opening and closing of the said conduit openings in the said accumulator. 8. A sequential compression device as claimed in any one of Claims 1 to 7 in which the said accumulator comprises an upper housing portion (14) and a lower housing portion (16), the said lower housing portion supporting the said pump (32), motor (38), and valve arrangement therein, the said upper housing portion (14) comprising a cover for enclosing the said lower housing portion. 9. A sequential compression device as claimed in any one of Claims 1 to 8 in which a dump valve (82) is disposed in the said housing (14,16), to discharge excess pressure from the said accumulator (18). 10. A sequential compression device as claimed in any one of Claims 1 to 9 in which the said pump (32) has a conduit (34) extending from an orifice in the said housing to provide an air source therefor. 11. A sequential compression device as claimed in any one of Claims 1 to 10 in which indicating means are provided for at least one of the said cam followers on each cam, so as to indicate the position of the valve in relation to its respective conduit, to provide feedback for control of the said device.

Inventors: DYE, JOHN F., KOLSTEDT, MARK
Applicants: THE KENDALL COMPANY
Application year: 1989
Main classification: A61H23
IPC codes: A61H23