EXTERNAL PRESSURE CIRCULATORY ASSIST

• US 3,734,087 A
• Filed: 11/11/1971
• Issued: 05/22/1973
• Est. Priority Date: 11/11/1971
• Status: Expired due to Term

• Current Assignee: Harold S. Sauer, John M. Colman, Nubar D. Hagopian
• Original Assignee: Harold S. Sauer, John M. Colman, Nubar D. Hagopian
• Inventors: Sauer, Harold S., Hagopian, Nubar D., Colman, John M.
• Primary Examiner(s): Trapp, Lawrence W.
• Application Number:
  US05/197,824
• Time in Patent Office: 558 Days
• Field of Search: 128/24,30.2,64
• US Class Current: 601/152
• CPC Class Codes: A61H 2201/0103 inflatable
• CPC Class Codes: A61H 2201/1238 with hydraulic or pneumatic drive
• CPC Class Codes: A61H 2201/1645 contoured to fit the user
• CPC Class Codes: A61H 2201/5071 Pressure sensors
• CPC Class Codes: A61H 2205/10 Leg
• CPC Class Codes: A61H 31/006 Power driven
• 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

Improved external pressure circulatory assist device of the type which utilizes an electrocardiogram signal to facilitate synchronization of its pressure pulse with the heartbeat. The improvements include a more efficient and clinically suitable mechanical means to induce pressure variations in the legs of a patient, and an automatic control means to maintain the proper pressurization even during physiological changes in the limbs of the patient being treated, and control means to monitor and adjust the pressure wave to achieve the proper phasing of the pressure wave with the cardiac cycle during treatment of the patient.

Claims

1. In apparatus for applying external pressure circulatory assist action to the legs of a patient in cyclic synchronization with the heartbeat of said patient by pressurizing said legs, the improvement wherein said apparatus comprises:

A. a unitary bladder adapted for wrapping about a patient'"'"''"'"'s legs and holding a quantity of liquid, B. mechanical displacement means in contact with outside wall of said bladder and forming means to press against said bladder, said means forming the primary means for obtaining the aforesaid pressure assist action, and C. a unitary upper leg casing member and a unitary lower leg casing member having means, said casing members adapted for attachment to form a compartment to enclose said bladder, said casing members having sufficient brace means between leg sections thereof to avoid any substantial outward deflection of said leg casing members during said pressurizing of said fluid.

2. a trace derived from an arterial pressure sensor, B. means for visually displaying of the relative time duration of a pressure command signal on said traces, and C. manual means to adjust the relative timing and duration of said pressure command signal, while simultaneously achieving a visual adjustment of said signal to bring it into the desired relationship to said EKG trace, or arterial trace.

3. Apparatus as defined in claim 2 wherein said leg-enclosing zones are conical in shape and adapted to dissipate stresses exerted thereon as hoop stresses, thereby resisting any substantial deflection or deformation of said zones.

4. Apparatus as defined in claim 3 wherein said pressurizing means has a displacement capacity of at least 100 cubic inches and comprises means for actuating said platen through a stroke length of up to about 3.5 inches.

5. Apparatus as defined in claim 2 wherein said casing members, bladder and displacement means are all placed within an envelope forming means to maintain sub-atmospheric pressure therearound.

6. Apparatus as defined in claim 1 wherein said mechanical displacement means is placed within said compartment formed by said casing and also comprises a platen and a power linkage forming means to impart a power stroke thereto characterized by a substantial loss of velocity of said platen as the platen rises against said bladder.

7. Apparatus as defined in claim 6 wherein said pressurizing means has a displacement capacity of at least 100 cubic inches and comprises means for actuating said platen through a stroke length of up to about 3.5 inches.

8. Apparatus as defined in claim 1 wherein said casing members, bladder and displacement means are all placed within an envelope forming means to maintain sub-atomspheric pressure therearound.

9. Apparatus as defined in claim 8 wherein said pressurizing means has a displacement capacity of at least 100 cubic inches and comprises means for actuating said platen through a stroke length of up to about 3.5 inches.

10. In apparatus for applying external pressure circulatory assist action to the limbs of a patient in synchronization with the heartbeat of said patient, and wherein said assist is achieved by pressurizing a fluid-filled bladder surrounding said limbs, the improvement wherein said apparatus comprises a mechanical pressurizing member positioned generally between said limbs and in contact with an outside wall of said bladder and forming means to presS against said bladder, said bladder adapted for reciprocal movement in contact with said bladder, said mechanical means comprising a power-transmitting linkage forming means to impart a power stroke characterized by a substantial loss of velocity of said pressurizing member as the pressure of said contact is increased in the bladder during said stroke.

11. Apparatus as defined in claim 10 wherein said bladder and mechanical pressurizing means are enclosed in a rigid casing, wherein the casing is enclosed in an envelope, and wherein a suction pump is operably connected to the interior of said envelope forming means to maintain a sub-atmospheric pressure within said envelope of between atmospheric pressure and about minus 100 mm of mercury below atmospheric pressure.

12. Apparatus as defined in claim 11 wherein said pressurizing means has a displacement capacity of at least 100 cubic inches and comprises means for actuating said platen through a stroke of up to about 3.5 inches.

13. Apparatus as defined in claim 10 wherein said pressurizing means has a displacement capacity of at least 100 cubic inches and comprises means for actuating said platent through a stroke of up to about 3.5 inches.

14. In apparatus for applying external pressure circulatory assist action to the limbs of a patient in cyclic synchronization with a heartbeat of said patient, and wherein said assist is achieved by means for pressurizing a fluid-filled bladder surrounding said limbs, the improvement wherein pump means is provided for adding to or subtracting fluid from said bladder, said pump means being responsive to the pressure within said bladder, through a bladder-pressure sensing means and a control circuit, and wherein said pump is responsive to said sensing means to receive an independent command signal therefrom on each heartbeat cycle of said patient.

15. Apparatus as defined in claim 14 wherein said pump means has an operating period of about 0.5 seconds.

16. Apparatus as defined in claim 14 comprising a reciprocating mechanical member forming displacement means to engage said bladder and pressurize the fluid therein.

17. Apparatus as defined in claim 16 wherein said pressure-sensing means is an indirect sensing means comprising a displacement-sensing monitor adapted to sense the position of said mechanical pressure-transmitting device, to transmit a signal indicative of said position, and consequently indicative of said pressure in said bladder.

18. Apparatus for applying external pressure assist action to the limbs of a patient in cyclic synchronization with the heartbeat of said patient, wherein said assist is achieved with means for transmitting pressure to said limbs through a fluid-filled bladder surrounding said limbs, the improvement wherein the apparatus includes a visual cycle-phasing monitor comprising:

A. a multi-channel display device adapted to display

19. Apparatus for applying external pressure assist action to the limbs of a patient in cyclic synchronization with the heartbeat of said patient, wherein said assist is achieved with means for transmitting pressure through a hydraulic cylinder to said limbs through a fluid-filled bladder surrounding said limbs, the improvement wherein the apparatus includes A. an ideal pressure waveform generator means, B. actual leg pressure waveform sensing means, C. means for continually comparing said ideal and actual waveforms, and D. variable valve means, responsive to a signaL from said comparing means, to modify fluid flow to said hydraulic cylinder and thereby more nearly achieve said ideal-pressure waveform.

20. Apparatus as defined in claim 19 comprising:

A. a multi-channel oscilloscope adapted to display

21. Apparatus as defined in claim 20 wherein pump means is provided for adding to or subtracting fluid from said bladder, said pump means being responsive to the pressure within said bladder, through a bladder-pressure sensing means and a control circuit, and wherein said pump is responsive to said sensing means to receive an independent command signal therefrom on each heartbeat cycle of said patient.

22. Apparatus as defined in claim 1 wherein said pressurizing means has a displacement capacity of at least 100 cubic inches and comprises means for actuating said platen through a stroke length of up to about 3.5 inches.

23. In apparatus as defined in claim 1 for applying external pressure circulatory assist action to the limbs of a patient in cyclic synchronization with a heartbeat of said patient, and wherein said assist is achieved by means for pressurizing a fluid-filled bladder surrounding said limbs, the improvement wherein pump means is provided for adding to or subtracting the fluid from said bladder, said pump means being responsive to the pressure within said bladder, through a bladder-pressure sensing means and a control circuit, and wherein said pump is responsive to said sensing means to receive an independent command signal therefrom on each heartbeat cycle of said patient.

24. Apparatus as defined in claim 23 wherein said pump means has an operating period of about 0.5 seconds.

25. Apparatus as defined in claim 24 wherein said leg-enclosing zones are conical in shape and adapted to dissipate stresses exerted thereon as hoop stresses, thereby resisting any substantial deflection or deformation of said zones.

26. In apparatus as defined in claim 23 for applying external pressure circulatory assist action to the limbs of a patient in cyclic synchronization with a heartbeat of said patient, and wherein said assist is achieved by means for pressurizing a fluid-filled bladder surrounding said limbs, the improvement wherein pump means is provided for adding to or subtracting fluid from said bladder, said pump means being responsive to the pressure within said bladder, through a bladder-pressure sensing means and a control circuit, and wherein said pump is responsive to said sensing means to receive an independent command signal therefrom on each heartbeat cycle of said patient.

27. Apparatus as defined in claim 26 wherein said pump means has an operating period of about 0.5 seconds.

28. Apparatus as defined in claim 27 wherein said leg-enclosing zones are conical in shape and adapted to dissipate stresses exerted thereon as hoop stresses, thereby resisting any substantial deflection or deformation of said zones.

29. Apparatus as defined in claim 26 comprising a reciprocating mechanical member forming displacement means to engage said bladder and pressurize the fluid therein.

30. Apparatus as defined in claim 29 wherein said pressure-sensing means is an indirect sensing means comprising a displacement-sensing monitor adapted to sense the position of said mechanical pressure-transmitting device, to transmit a signal indicative of said position, and consequently indicative of said pressure in said bladder.

31. Apparatus as defined in claim 1 for applying external pressure assist action to the limbs of a patient in cyclic synchronization with the heartbeat of said patient, wherein said assist is achieved with means for transmitting pressure to said limbs through a fluid-filled bladder surrounding said limbs, the improvement wherein the apparatus includes a visual cycle-phasing monitor comprising:

A. a multi-channel display device adapted to display

32. Apparatus as defined in claim 31 wherein said leg-enclosing zones are conical in shape and adapted to dissipate stresses exerted thereon as hoop stresses, thereby resisting any substantial deflection or deformation of said zones.

33. Apparatus as defined in claim 31 wherein said pressurizing means has a displacement capacity of at least 100 cubic inches and comprises means for actuating said platen through a stroke of up to about 3.5 inches.

34. Apparatus as defined in claim 16 for applying external pressure assist action to the limbs of a patient in cyclic synchronization with the heartbeat of said patient, wherein said assist is achieved with means for transmitting pressure to said limbs through a fluid-filled bladder surrounding said limbs, the improvement wherein the apparatus includes a visual cycle-phasing monitor comprising:

A. a multi-channel display device adapted to display

35. Apparatus as defined in claim 33 wherein said leg-enclosing zones are conical in shape and adapted to dissipate stresses exerted thereon as hoop stresses, thereby resisting any substantial deflection or deformation of said zones.

36. Apparatus as defined in claim 34 wherein said pressure-sensing means is an indirect sensing means comprising a displacement-sensing monitor adapted to sense the position of said mechanical pressure-transmitting device, to transmit a signal indicative of said position, and consequently indicative of said pressure in said bladder.

37. Apparatus as defined in claim 23 wherein said leg-enclosing zones are conical in shape and adapted to dissipate stresses exerted thereon as hoop stresses, thereby resisting any substantial deflection or deformation of said zones.

38. Apparatus as defined in claim 1 for applying external pressure assist action to the limbs of a patient in cyclic synchronization with the heartbeat of said patient, wherein said assist is achieved with means for transmitting pressure through an hydraulic cylinder to said limbs through a fluid-filled bladder surrounding said limbs, the improvement wherein the apparatus includes A. an ideal pressure waveform generator means, B. actual leg pressure waveform sensing means, C. means for continually comparing said ideal and actual waveforms, and D. variable valve means, responsive to a signal from said comparing means, to modify fluid flow to said sydraulic cylinder and thereby more nearly achieve said ideal-pressure waveform.

39. Apparatus as defined in claim 38 comprising:

A. a multi-channel oscilloscope adapted to display

40. Apparatus as defined in claim 39 wherein pump means is provided for adding to or subtracting fluid from said bladder, said pump means being responsive to the pressure within said bladder, through a bladder-pressure sensing means and a control circuit, and wherein said pump is responsive to said sensing means to receive an independent command signal therefrom on each heartbeat cycle of said patient.

41. Apparatus as defined in claim 40 wherein said pump means has an operating period of about 0.5 seconds.

42. Apparatus as defined in claim 38 wherein said pump means has an operating period of about 0.5 seconds.

43. Apparatus as defined in claim 39 wherein said pump means has an operating period of about 0.5 seconds.