Apparatus for augmenting venous blood flow

• US 3,892,229 A
• Filed: 12/06/1973
• Issued: 07/01/1975
• Est. Priority Date: 12/06/1973
• Status: Expired due to Term

• Current Assignee: Duane F. Taylor, Harry F. Everett, Norman C. Williams, Richard C. Everett
• Original Assignee: Duane F. Taylor, Harry F. Everett, Norman C. Williams, Richard C. Everett
• Inventors: Everett, Richard C., Taylor, Duane F., Everett, Harry F., Williams, Norman C.
• Primary Examiner(s): Trapp, Lawrence W.
• Application Number:
  US05/422,208
• Time in Patent Office: 572 Days
• Field of Search: 128/38-40,24R,64,DIG.10,DIG.20
• US Class Current: 601/152
• CPC Class Codes: A61H 2201/5056 pneumatically controlled
• CPC Class Codes: A61H 9/0078 with intermittent or alternately inflated bladders or cuffs mattresses for preventing bed-sores with alternated pressurized chambers A61G7/05776

Abstract

Apparatus, adapted for use in explosive as well as non-explosive atmospheric environments, for alternately applying intermittent compression to the legs of a patient during surgery, postoperative recovery periods and other periods of muscular inactivity to accelerate venous blood flow in the lower extremities and inferior vena cava and thereby prevent blood clotting in these vessels. A pair of double-walled pneumatic leggings adapted to extend from the ankle to the knee of the patient are provided for fitting on each leg. Each legging is connected by a separate conduit to a non-electrical regulating and timing control circuit adapted to receive compressed air, oxygen or other pressurized gas from any available source and transmit it by means of periodic intermittent pulses alternately to each legging. The control circuit includes a pressure regulating valve for reducing the available inlet supply pressure to a suitable working pressure and adjustable metering valves for controllably varying the volumetric flow rate of gas to each legging to thereby control the time rate of pressure build-up of each pulse. Respective adjustable pressure relief valves are also provided for variably controlling the maximum pressure permitted in each legging and for relieving the pressure at the end of each pulse. The control circuit includes a timing system for causing the pulses to be delivered at alternate regular intervals to the respective leggings, such timing system being adapted to operate entirely by pneumatic actuation so as to eliminate explosion hazard in high oxygen environments. Such timing system comprises a two-diaphragm cycling valve for automatically regulating the alternate charge and discharge of a pair of accumulator tanks, each tank controlling by means of a predetermined rate of pressure increase the timing of the pulses to the respective leggings. The timing system is operatively independent of legging pressure to eliminate the possibility of cycle failure if a legging should develop a leak or become disconnected.

Claims

1. An alternating leg compression control unit adapted to be coupled with a pair of pressure leggings, said unit comprising:

a. inlet port means adapted for coupling to a source of pressurized fluid;

b. a pair of outlet port means adapted for coupling to said respective leggings; and

c. control means for conducting said fluid from said inlet port means to said respective outlet port means in periodic flow increments alternating between said respective outlet port means, said control means including fluid-operated timing means for starting each said flow increment in a predetermined periodic sequence, said timing means having no electrically actuated components.

2. The apparatus of claim 1 including a pressure regulator coupled with said inlet port means for automatically decreasing the pressure of said fluid received from said source to a predetermined pressure.

3. An alternating leg compression control unit adapted to be coupled with a pair of pressure leggings, said unit comprising:

a. inlet port means adapted for coupling to a source of pressurized fluid;

b. a pair of outlet port means adapted for coupling to said respective leggings;

c. control means for conducting said fluid from said inlet port means to said respective outlet port means in periodic flow increments alternating between said respective outlet port means;

d. said control means including timing means for starting each said flow increment in a predetermined periodic sequence, said timing means comprising a pressure responsive shuttle valve coupled to a pair of accumulator timing tanks, said valve having a first position for feeding pressurized fluid to a first one of said timing tanks and a second position for feeding pressurized fluid to said second timing tank; and

e. said control means further comprising a pair of control valves, each responsive to the pressure in one of said timing tanks, for selectively initiating or interrupting the flow of pressurized fluid to a respective one of said outlet port means in response to said timing tank pressure.

4. The apparatus of claim 3 wherein said shuttle valve includes means responsive to the pressure in said respective timing tanks for interrupting the flow of fluid to a respective timing tank when the pressure in said tank increases to a predetermined level, and simultaneously therewith initiating a flow of fluid to said other timing tank.

5. The apparatus of claim 4 wherein said shuttle valve comprises a pair of flexible diaphragms joined together for movement in unison with one another, said valve including means responsive to the pressure in said respective timing tanks for moving said diaphragm pair in one direction when the pressure in a respective timing tank increases to a predetermined level and for moving said diaphragm pair in the opposite direction when the pressure in the other said timing tank increases to a predetermined level.

6. The apparatus of claim 3 wherein each of said control valves includes means for initiating a flow of pressurized fluid to a respective outlet port means whenever the pressure in a respective timing tank decreases to a predetermined pressure level.

7. The apparatus of claim 3 including first restrictor means interposed between said first timing tank and said shuttle valve and second restrictor means interposed between said second timing tank and said shuttle valve for controlling the rate of flow of pressurized fluid into said respectiVe timing tanks.

8. The apparatus of claim 3 including means for isolating the fluid in said timing tanks from the fluid conducted to said outlet port means so as to render the pressure in said timing tanks independent of the pressure at said outlet port means.

9. The apparatus of claim 3 including pressure regulator means coupled with said inlet port means for automatically decreasing the pressure of said fluid received from said source to a predetermined pressure.

10. The apparatus of claim 3 including relief valve means coupled to said outlet port means for limiting the pressure at said outlet port means to a predetermined maximum pressure.

11. The apparatus of claim 10 wherein said relief valve means comprises a pair of relief valves, each coupled with a respective one of said outlet port means and each having adjustable means for independently varying the predetermined maximum pressure at said respective outlet port means.

12. The apparatus of claim 10 wherein said relief valve means comprises a pair of relief valves, each coupled with a respective one of said outlet port means and each having means responsive to the pressure in a respective timing tank for retaining said relief valve in its relieving condition for a predetermined period of time after said predetermined maximum pressure has been reached.

13. The apparatus of claim 12 wherein each said relief valve includes means for interrupting the flow of pressurized fluid to said respective outlet port means while said relief valve is in said relieving condition.

14. The apparatus of claim 3 including adjustable metering valve means interposed between said inlet port means and said outlet port means for variably regulating the flow rate of pressurized fluid to said outlet port means.

15. The apparatus of claim 14 wherein said metering valve means comprises a pair of metering valves, each interposed between said inlet port means and a respective one of said outlet port means and each having adjustable means for independently varying the flow rate of pressurized fluid to said respective outlet port means.

16. An alternating leg compression control unit comprising means for delivering pressurized fluid through a pair of outlet ports to a pair of pressure leggings in periodic flow increments alternating between said respective outlet ports, and adjustable means for varying the time rate of pressure increase at said outlet ports when said leggings are coupled thereto.

17. The apparatus of claim 16 wherein a pair of said adjustable means for varying said rate of pressure increase are provided, each being coupled to a respective outlet port and each being separately adjustable for varying the time rate of pressure increase at said respective outlet ports independently of one another.

18. An alternating leg compression control unit comprising means for delivering pressurized fluid in flow increments through a pair of outlet ports to a pair of pressure leggings, and timing means adapted to operate solely by fluid pressure for automatically initiating each said flow increment in a periodic sequence.

19. An alternating leg compression control unit comprising:

means for delivering pressurized fluid through a pair of outlet ports to a pair of pressure leggings in periodic flow increments alternating between said respective outlet ports, and a pair of said adjustable pressure limiting means for variably limiting the maximum pressure at said respective outlet ports, each of said adjustable pressure limiting means being coupled to a respective outlet port and each being separately adjustable for varying the maximum pressure at said respective outlet ports independently of one another.

20. An alternating leg compression control unit comprising:

means for delivering pressurized fluid through a pair of outlet ports to a pair of pressure leggings in periodic flow increment pulses alternating between said respective outlet ports, and a pair of said adjusTable means for varying the duration of each of said pulses, each of said adjustable pressure limiting means being coupled to a respective outlet port and each being separately adjustable for varying pulse duration at one of said outlet ports independently of pulse duration at the other said outlet port.