Method for focused delivery of venous flow for artificial impluse compression of an anatomical foot pump

• US 5,669,872 A
• Filed: 03/06/1995
• Issued: 09/23/1997
• Est. Priority Date: 11/23/1992
• Status: Expired due to Term

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Novamedix Limited (Orthofix Medical Inc.)
• Inventors: Fox, Roger Harrington
• Primary Examiner(s): Brown, Michael A.
• Assistant Examiner(s): KOO, BENJAMIN K
• Application Number:
  US08/398,853
• Time in Patent Office: 932 Days
• Field of Search: 601/198, 601/149, 601/150, 601/151, 601/152, 128/898, 128/DIG. 20
• US Class Current: 601/152
• CPC Class Codes: A61H 2205/12 Feet
• 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

A method for therapeutically or prophylactically treating a diagnosed or potential deep-vein thrombosis involves intermittent application of tourniquet action to the leg at a location preferably close to the ankle, i.e., at the distal-calf region of the leg, in time-coordinated relation to artificially stimulated foot-pump action; the level of tourniquet action is such as to reduce the availability of superficial veins to carry the venous-return flow that is stimulated by foot-pump action, and the level of tourniquet action is also insufficient to materially affect access to deep-veins which are the primary target of therapeutic or prophylactic treatment.

In a modification, the sequencing of tourniquet and foot-pump action is changed to enhance the priming of blood in the plantar veins of a foot which must remain elevated above the heart level of a patient confined to bed, whereby circulation can be more effectively stimulated by foot-pump action.

Claims

1. The method of treating a leg which is suspended in a raised position above the level of the body of a patient who must lie in bed, which method comprises the following sequence of steps:

(a) transiently applying a first level of tourniquet pressure to the leg solely at a distal-calf location and along no other region of the leg;

(b) retaining the applied tourniquet pressure for a preliminary period of time to enable blood to accumulate in the plantar veins of the leg;

(c) injecting a thrombolytic agent into a vein in the dorsum of the foot;

(d) thereafter applying transient venous-pumping pressure to the plantar region of the leg, wherein the venous-pumping pressure peaks at a level in excess of the retained transient tourniquet pressure;

(e) relieving the retained tourniquet pressure, and thereafter relieving the venous-pumping pressure; and

(f) cyclically repeating steps (a) to (e) in a pattern wherein the application of venous-pumping pressure is rapid and wherein the period of cyclical repetition is greater than the combined period of tourniquet-pressure application and of venous-pumping pressure.

2. The method of claim 1, wherein said period for step (b) is up to substantially 10 seconds.

3. The method of claim 1, wherein said period for step (b) is at least 10 seconds prior to step (d).

4. The method of claim 1, wherein the relief of tourniquet pressure is substantially coincident with step (d).

5. The method of claim 1, wherein the rate of applying the tourniquet pressure of step (a) is more slow than the rate of applying the venous-pumping pressure of step (d).

6. The method of claim 1, wherein said period for step (b) is approximately one half of the period of cyclical repetition.

7. The method of claim 1, wherein the relief of venous-pumping pressure is upon achievement of said peak-pressure level.

8. The method of claim 1, wherein said peak-pressure level is maintained for a period up to 5 seconds before relief of venous-pumping pressure.

9. The method of claim 8, wherein the maintenance of said peak-pressure level is for substantially three seconds.

10. The method of claim 1, wherein the period of cyclical repetition is in the range of 15 to 60 seconds.

11. The method of claim 10, wherein said period is substantially 20 seconds.

12. The method of claim 1, wherein a venous-pumping rise to peak pressure is effected within two seconds.

13. The method of claim 12, wherein a venous-pumping rise to peak pressure is effected within 0.5 second or less.

14. The method of claim 1, wherein a tourniquet-pressure rise to said first level is effected within no less than one second.

15. The method of claim 1, wherein said first level of pressure is in the range of 30 to 100-mm Hg.

16. The method of claim 15, wherein said peak-pressure level is in the range up to substantially 225-mm Hg.

17. The method of claim 15, in which said peak-pressure level is at least substantially 200-mm Hg.

18. The method of claim 1, wherein said first level of pressure is in the range of 40 to 60-mm Hg.

20. The method of claim 1, comprising a preliminary step of installing a caval filter before performing steps (a) to (e).

19. The method of treating a leg which is suspended in a raised position above the level of the body of a patient who must lie in bed, which method comprises the following sequence of steps:

(a) transiently applying a first level of tourniquet pressure to the leg solely at a distal-calf location and along no other region of the leg;

(b) retaining the applied tourniquet pressure for a preliminary period of time to enable blood to accumulate in the plantar veins of the leg;

(c) thereafter relieving the retained tourniquet pressure and applying transient venous-pumping pressure to the plantar region of the leg, wherein the venous-pumping pressure peaks at a level in excess of the retained tourniquet pressure;

(d) relieving the venous-pumping pressure; and

(e) cyclically repeating steps (a) to (d) in a pattern wherein the application of venous-pumping pressure is rapid, wherein the application of tourniquet pressure is slower than said rapid inflation, and wherein the period of cyclical repetition is at least twice said preliminary period.

21. The method of treating a leg which is suspended in a raised position above the level of the body of a patient who must lie in bed, which method comprises the steps of:

(a) transiently applying a first level of tourniquet pressure to the leg solely at a distal-calf location and along no other region of the leg;

(b) retaining the applied tourniquet pressure for a preliminary period of time to enable blood to accumulate in the plantar veins of the leg;

(c) thereafter applying transient venous-pumping pressure to the plantar region of the leg, wherein the venous-pumping pressure peaks at a level in excess of the retained transient tourniquet pressure;

(d) relieving the tourniquet pressure at substantially the time of transiently applying the venous-pumping pressure; and

(e) cyclically repeating steps (a) to (d) in a pattern wherein (i) the application of venous-pumping pressure is rapid, (ii) wherein the period of cyclical repetition is substantially greater than the period of applied venous-pumping pressure, and (iii) wherein a dwell period of relieved pressure is provided, and said dwell period is at least equal to the preliminary period of time, said dwell period being prior to recycled repetition of steps (a) to (d).

22. The method of minimizing development of a DVT region in an afflicted leg, which method comprises the steps of:

(a) transiently applying a first level of tourniquet pressure to the leg solely at a location that is distal to the DVT region and along no other region of the leg;

(b) applying transient venous-pumping pressure to the plantar region of the foot of the leg, wherein the venous-pumping pressure peaks at a level in excess of the transient tourniquet pressure;

(c) relieving the venous-pumping pressure;

(d) maintaining the tourniquet pressure until the venous-pumping pressure has been relieved to substantially the level of tourniquet pressure, and then relieving the tourniquet pressure; and

(e) cyclically repeating steps (a) to (d) in a pattern wherein the application of transient venous-pumping pressure is relatively rapid and wherein the period of cyclical repetition is relatively great.

23. The method of minimizing development of a DVT region in an afflicted leg, which method comprises the steps of:

(a) transiently applying a first level of tourniquet pressure to the leg at a location that is distal to the DVT region and along no other region of the leg;

(b) applying transient venous-pumping pressure to the plantar region of the foot of the leg, wherein the venous-pumping pressure peaks at a level in excess of the transient tourniquet pressure;

(c) relieving the venous-pumping pressure;

(d) relieving the tourniquet pressure once the venous-pumping pressure has been relieved to a level below said first level;

(e) cyclically repeating steps (a) to (d) in a pattern wherein the application of transient venous-pumping pressure is relatively rapid and wherein the period of cyclical repetition is relatively great; and

(f) injecting a thrombolytic agent into a vein in the dorsum of the foot at least during an interval between steps (a) to (d) of each cycle.

24. The method of minimizing development of a DVT region in an afflicted leg, which method comprises the steps of:

(a) as a preliminary step, installing a caval filter in the inferior vena cava;

(b) transiently applying a first level of tourniquet pressure to the leg solely at a location that is distal to the DVT region and along no other portion of the leg;

(c) applying transient venous-pumping pressure to the plantar region of the foot of the leg, wherein the venous-pumping pressure peaks at a level in excess of the transient tourniquet pressure;

(d) relieving the venous-pumping pressure;

(e) maintaining the tourniquet pressure until the venous-pumping pressure has been relieved to substantially the level of tourniquet pressure and then relieving the tourniquet pressure; and

(f) cyclically repeating steps (a) to (e) in a pattern wherein the application of transient venous-pumping pressure is relatively rapid and wherein the period of cyclical repetition is relatively great.

25. The method of using inflatable tourniquet-cuff action applied only to the calf of a leg, wherein such use is in coordinated concurrence with inflatable foot-pump action at the plantar region of the leg, which method comprises the following sequence of steps:

(a) transiently inflating the cuff to a first level of tourniquet-pressure action on superficial veins of the calf and along no other region of the leg;

(b) transiently inflating the foot pump to a peak-pressure level of foot-pump action in excess of said first level;

(c) relieving the foot-pump pressure;

(d) relieving the cuff pressure, said tourniquet-cuff pressure acting for substantially the same amount of time as the foot-pump pressure; and

(e) cyclically repeating steps (a) and (d) in a pattern wherein inflation of the foot pump is relatively rapid and wherein the period of cyclical repetition is relatively great.

26. The method of claim 25, in which the relief of foot-pump pressure is upon achievement of said peak-pressure level.

27. The method of claim 25, in which said peak-pressure level is maintained for a period up to 5 seconds before relief of foot-pump pressure.

28. The method of claim 27, in which the maintenance of said peak-pressure level is for substantially three seconds.

29. The method of claim 25, in which the period of cyclical repetition is in the range of 15 to 60 seconds.

30. The method of claim 29, in which said period is substantially 20 seconds.

31. The method of claim 25, in which the rate of inflation of the cuff is slower than the rate of inflation of the foot pump.

32. The method of claim 31, in which foot-pump inflation to peak pressure is effected within one second.

33. The method of claim 31, in which foot-pump inflation to peak pressure is effected within 0.5 second or less.

34. The method of claim 33, in which cuff inflation to said first level is effected within no less than one second.

35. The method of claim 25, comprising a preliminary step of installing a caval filter before performing steps (a) to (e).

36. The method of claim 25, in which said first level of pressure is in the range of 30 to 100-mm Hg.

37. The method of claim 36, in which said peak-pressure level is in the range up to substantially 225-mm Hg.

38. The method of claim 36, in which said peak-pressure level is at least substantially 200-mm Hg.

39. The method of claim 25, in which said first level of pressure is in the range of 40 to 60-mm Hg.

40. The method of prophylactically or therapeutically treating a leg for a known or potential DVT condition, which method comprises the following sequence of steps:

(a) transiently applying a first level of tourniquet pressure to the leg solely at a distal-calf location and along no other region of the leg;

(b) applying transient venous-pumping pressure to the plantar region of the leg, wherein the venous-pumping pressure peaks at a level in excess of the transient tourniquet pressure;

(c) relieving the venous-pumping pressure;

said tourniquet pressure acting for substantially the same amount of time as the venous-pumping pressure at the plantar region of the leg;

(d) relieving the tourniquet pressure; and

(e) cyclically repeating steps (a) to (d) in a pattern wherein the application of transient venous-pumping pressure is relatively rapid and wherein the period of cyclical repetition is relatively great.

41. The method of claim 40, wherein said first level is varied in the course of a given treatment involving multiple cycles.

42. The method of claim 40, wherein the peak level of step (b) is varied in the course of a given treatment involving multiple cycles.

43. The method of claim 40, wherein step (a) is concurrently also applied proximally to the distal-calf location.

44. The method of treating a leg which is suspended in a raised position above the level of the body of a patient who must lie in bed, which method comprises the steps of:

(a) transiently applying a first level of tourniquet pressure to the leg solely at a distal-calf location and along no other region of the leg;

(b) retaining the applied tourniquet pressure for a period of time to enable blood to accumulate in the plantar veins of the leg;

(c) thereafter applying transient venous-pumping pressure to the plantar region of the leg, wherein the venous-pumping pressure peaks at a level in excess of the retained transient tourniquet pressure;

(d) relieving the venous-pumping pressure and the retained tourniquet pressure, said tourniquet pressure acting not only for said preliminary period of time but also for substantially the same amount of time as the venous-pumping pressure; and

(e) cyclically repeating steps (a) to (d) in a pattern wherein (i) the application of venous-pumping pressure is relatively rapid, (ii) wherein the period of cyclical repetition is relatively great, and (iii) wherein a dwell period of relieved pressure is provided, and said dwell period is at least equal to the preliminary period of time, said dwell period being prior to recycled repetition of steps (a) to (d).

45. The method of claim 44, wherein the period of time for step (b) is relatively long.

46. The method of claim 44, wherein said period for step (b) is up to substantially 10 seconds.

47. The method of claim 44, wherein said period for step (b) is at least 10 seconds prior to step (c).

48. The method of claim 44, wherein said period for step (b) is approximately one half of the period of cyclical repetition.

49. The method of stimulating venous-return flow in a human leg while preferentially enhancing such flow in deep veins of the leg, with concomitant restriction of such flow in superficial veins of the leg, which method comprises the steps of:

(a) transiently applying a first level of tourniquet pressure to a calf region of the leg and along no other region of the leg;

(b) applying transient venous-pumping pressure to the plantar region of the foot of the leg, wherein the venous-pumping pressure peaks at a level in excess of the transient tourniquet pressure;

(c) relieving the venous-pumping pressure;

(d) relieving the tourniquet pressure once the venous-pumping pressure has been relieved to a level below said first level;

(e) cyclically repeating steps (a) to (d) in a pattern wherein the application of transient venous-pumping pressure is relatively rapid and wherein the period of cyclical repetition is relatively great; and

(f) injecting the thrombolytic agent into a vein in the dorsum of the foot at least during an interval between step (d) of one cycle and step (a) of the next succeeding cycle.

50. The method of stimulating venous-return flow in a human leg while preferentially enhancing such flow in deep veins of the leg, with the concomitant restriction of such flow in superficial veins of the leg, which method comprises the steps of:

(a) transiently applying a first level of tourniquet pressure solely to a calf region of the leg and along no other region of the leg;

(b) applying transient venous-pumping pressure to the plantar region of the foot of the leg, wherein the venous-pumping pressure peaks at a level in excess of the transient tourniquet pressure;

(c) relieving the venous-pumping pressure;

(d) relieving the tourniquet pressure once the venous-pumping pressure has been relieved to a level below said first level, the tourniquet pressure acting for substantially the same amount of time as the venous-pumping pressure at the plantar region of the foot; and

(e) cyclically repeating steps (a) to (d) in a pattern wherein the application of transient venous-pumping pressure is relatively rapid and wherein the period of cyclical repetition is relatively great.

51. The method of claim 50, comprising a preliminary step of installing a caval filter before performing steps (a) to (e).

52. The method of claim 50, wherein steps (a) and (b) are preceded by:

(a'"'"') selection of an inflatable tourniquet cuff and application of the cuff to the calf region, and

(b'"'"') selection of an inflatable foot pump and application of the foot pump to the plantar region; and

wherein thereafter;

step (a) is a transient inflation of the cuff to a first level of tourniquet-pressure action; and

step (b) is a transient inflation of the foot pump, to a peak-pressure level in excess of said first level.

53. The method of claim 50, in application to a prophylactic or a therapeutic treatment of a leg, wherein step (a) is applied at a distal-calf location.

54. The method of claim 50, in treatment of a leg which is suspended in a raised position above the level of the body of a patient who must lie in bed, wherein step (a) is applied at a distal-calf location and for a preliminary period of time sufficient for blood to accumulate in the plantar veins of the leg.

55. The method of treating a traumatized region of a human leg wherein the trauma exists at a location proximal to the distal calf, said method comprising the steps of applying inflatable tourniquet-cuff action only to the distal calf and in a coordinated program of inflatable foot-pump action at the plantar region of the leg, said program comprising the steps of:

(a) transiently inflating the cuff to a first level of tourniquet-pressure action on superficial veins of the distal calf;

(b) transiently inflating the foot-pump to a peak-pressure level of foot-pump action in excess of said first level;

(c) relieving the foot-pump pressure;

(d) relieving the cuff pressure;

(e) cyclically repeating steps (a) to (d) in a pattern wherein inflation of the foot-pump is relatively rapid and wherein the period of cyclical repetition is relatively great; and

(f) injecting a thrombolytic agent into a vein in the foot at least during an interval between step (d) of one cycle and step (a) of the next succeeding cycle.