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Publication numberUS3518702 A
Publication typeGrant
Publication dateJul 7, 1970
Filing dateJan 23, 1967
Priority dateJan 23, 1967
Publication numberUS 3518702 A, US 3518702A, US-A-3518702, US3518702 A, US3518702A
InventorsRussa Joseph A La
Original AssigneeFarrand Optical Co Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Implantable body actuated artificial heart system
US 3518702 A
Images(8)
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Description  (OCR text may contain errors)

July 7, 1970 J. A. LA RUSSA IMPLANTABLE -BODY ACTUATED ARTIF ICIAL HEART SYSTEM Filed Jan. 23, 1967 8 Sheets-Sheet 1 FIG. 10

INVENTOR JOSEPH A. LQRUSSA BY 31a, dd-m ATTORNEYS July 7, 1970 J. A. LA RussA IMPLANTABLE BODY ACTUATED ARTIFICIAL HEART SYSTEM Filed Jan. 23, 1967 8 Sheets-Sheet 2 FIG; 2

3 M m. wum 1 m B W.

M mm Mm A 1 m I \\f\\\ u a %m INVENTOR JOSEPH A. LORUSSA BY pm,zmaaa ATTORNEYS July 7, 1970 J. A. LA RUSSA IMPLANTABLE BODY ACTUATED ARTIFICIAL HEART SYSTEM Filed Jan. 23, 1967 8 Sheets-Sheet 5 1m .3 m 8 \MM m E w 5 I B m M H ,W P E s J 3 p 9 7 M mm m m 7 8 m w 7 m w J y GI I m mm m 4 Q 5 4 M F 5 V MMO M ATTORNEYS July 7, 1970 J. A. LA RUSSA IMPLANTABLE BODY ACTUATED ARTIFICIAL HEART SYSTEM Filed Jan. 23, 1967 8 Sheets-Sheet 4 ATTORNEYS y 1970 J. A. LA RUSSA 3,518,702

IMPLANTABLE BODY ACTUATED ARTIFICIAL HEART SYSTEM Filed Jan. 23, 1967 8 Sheets-Sheet 5 FIG. 5

INVENTOR JOSEPH A. LORUSSA BYQAMJ, 5 w.

ATTORNEYS Jilly 7, 1970 J. A. LA RUSSA IMPLANTABLE BODY ACTUAIED ARTIFICIAL HEART SYSTEM Filed Jan. 23, 1967 8 Sheets-Sheet 6 July 7, 1970 J. A. LA RUSSA IMPLANTABLE BODY ACTUATED ARTIFICIAL HEART SYSTEM Filed Jan. 23, 1967 8 Sheets-Sheet 7 INVENTQR JOSEPH A. LORUSSA BYPM IZLwmAWo-JZ a uv 17 402444 ATTORNEYS July 7, 1970 J. A. LA RUSSA IMPLANTABLE BODY ACTUATED ARTIFICIAL HEART SYSTEM Filed Jan. 23, 1967 8 Sheets-Sheet 8 FIG. 8

INVENTOR JOSEPH A. L0 RUSSA BY PW,&.M M02;

ATTORNEYS United States Patent 3,518,702 IMPLANTABLE BODY ACTUATED ARTIFICIAL HEART SYSTEM Joseph A. La Russa, Crestwood, N.Y., assignor to Far-rand Optical Co., Inc. Filed Jan. 23, 1967, Ser. No. 611,090 Int. Cl. A61f 1/24 U.S. Cl. 3-1 Claims ABSTRACT OF THE DISCLOSURE An artificial heart system for maintaining a normal blood circulation within a living, breathing body which is totally implantable within the thoracic and pericardial cavities of the recipient body and which is adapted to be fully powered and regulated by the bodys chest and breathing muscles. The components of the artificial heart system comprise a reciprocating pneumatic or fluid pump, an artificial heart, and a control means. The reciprocating pump is adapted to be operably connected to the body chest and breathing muscles to produce pneumatic or fluid pressure in response to the reciprocatory action of the body breathing. The artificial heart is a pneumatic 0r fluid pressure actuated blood pump which is connected to the reciprocating pump and is adapted to circulate blood in the circulatory system under pneumatic or fluid power supplied by the reciprocating pump. The control means is operably connected between the reciprocating pump and the artificial heart for maintaining a proportion between the body breathing rate and the rate of circulation powered by the artificial heart thereby maintaining a normal blood circulation at a variable rate according to the requirement of the body.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to an artificial heart system adapted to be completely implanted within and fully powered by a living, breathing body with no external connections. More specifically, this invention relates to a pneumatically operated artificial heart system comprising a pneumatically operated artificial heart, a reciprocating plural element pneumatic pump for producing pneumatic pressure for the artificial heart, and a control means consisting of pneumatic accumulators for storing and releasing the operating pneumatic pressures and a control valve assembly for supplying pulses of pneumatic pressure to operate the artificial heart. The reciprocating pneumatic pump which powers this system is actuated by the relatively reciprocating movement during body breathing of the rib cage and diaphragm or other breathing muscles to generate pneumatic pressure to supply the pneumatic pressure accumulators. The control valve assembly operates to maintain a proportion between the body breathing rate (12 to l8 breaths a minute) and the pumping rate of the artificial heart (60 to 80 strokes a minute). Since the body breathing rate is governed by the carbon dioxide concentration in the blood and increases or decreases thereby in relation to the bodily oxygen requirement, the artificial heart pumping rate is likewise regulated in accordance with the body demands. The artificial heart systems of this invention are adapted for total implantation within the pericardial and thoracic cavities of the body as either a total replacement for the patients natural heart or as a means for assisting the natural heart to maintain a normal circulation.

Description of the prior art Considerable research effort has been directed to the development of a practical, totally implantable artificial 3,518,702 Patented July 7, 1970 heart prosthesis. Especial impetus to this research effort has been provided by the National Heart Institute, a branch of the United States Department of Health, Education and Welfare. The utility of a practical, totally implantable heart replacement or assist device is obvious. It has been estimated that the development of a practical artificial heart would extend the national life span by two years. (Medical World News, Apr. 2, 1965.)

Dr. Samuel A. Levine of the Harvard Medical School and Dr. B. K. Kussero of the University of Vermont in consultation with several other cardiologists have made tentative predictions as to the eflicacy of a total implant artificial heart and an implantable heart assist device. It has been predicted that at least 20% of acceptable candidates will survive with the help of a temporary assist device. Of those whose lives are extended by a temporary assist device, it is estimated that 25% will recover satisfactory cardiac function and be able to return to an active, useful life. For others with extensive myocardial fibrous and incipient left ventricle failure the prognosis will be severely restricted physical activity and, for the most part, gainful employment will not be possible. With respect to patients receiving a totally implanted permanent circulatory support, the outlook is more favorable. It is expected that about 60% of all these patients receiving either a permanent left ventricular assist device or a total heart replacement will return to a productive life, including gainful employment. An additional 25% will be limited in their activities to some extent but will not require continued hospitalization. In summary, it is estimated that about of all patients receiving permanent circulatory support will recover sufliciently to resume a normal life.

The practicability of an artificial heart system has been dramatically demonstrated by the recent use of externally powered pneumatic heart assist pumping devices for the postoperative recovery of open heart surgery patients. Such heart assist devices operate as an artificial ventricle which by-passes the patients left ventricle by pumping blood from the pulmonary vein to the aortic artery. Most noteworthy of these devices are the pneumatic diaphragm blood pump developed by Baylor University, Waco, Tex. and the artificial pneumatic ventricle device developed at Brooklyn Hospital, Brooklyn, N.Y. Both of these devices successfully sustained a patient after open heart surgery for periods up to 48 hours without any evidence of excessive hemolysis or excessive deterioration of the patients blood cells.

A major problem which must be overcome in a practical artificial heart design is the development of a reliable, long-life, totally implantable power source. The use of an external power source for all but post-operative recovery assist devices is undesirable in at least two respects. The primary disadvantage is that the blood pump would have to be connected by percutaneous leads. The presence of bacteria on the skin surface in close proximity to a tube or wire passing through the skin barrier would make infection a constant hazard to the patient. A second considerable disadvantage is that an external power source would prove cumbersome to the patient and would have the psychological effect of reminding the patient of his dependency upon his prosthesis.

A large number of totally implantable power sources have been proposed, all of which appear to be either impracticable or have serious disadvantages. The more practical power sources which have been proposed for total implantation are as follows: (1) a long-life rechargeable chemical battery, (2) the use of radiofrequency power or magnetic coupling form an external source which transmits power in the form of radiation through the chest wall, (3) a small radioisotope actuated electric battery and (4) a thermal isotope source for a thermodynamic engine. The use of externally located magnetic or radiofrequency power sources are impractical as they would require the location of the power source at or near the chest wall of the patient and therefore would prove cumbersome. Further, the implantation of chemical or radioactive sources within the patient are undesirable as the energy source would eventually become depleted and require periodic maintenance, possibly surgery, for reactivation or replacement with a new power source. In addition, chemical and radioactive power sources present dangers of radioactive or chemical contamination. Low frequency electro-magnetic energy coupling devices may have a yet unknown deleterious effect on the tissues of the chest wall.

A number of researchers have suggested the use of a thermodynamic engine powered by a thermoisotope source, and a thermonuclear steam engine having a suitable weight and volumetric displacement has reached the design stage (Medical World News, Apr. 2, 1965; Hamilton Standard, Feb. 11, 1966, Final Report to National Heart Institute, pp. 140, 174, 218). However, there is serious doubt as to whether the human body could tolerate the heat dissipation from an implanted thermal source, which in some designs would be dissipated into the blood by means of a heat exchanger.

A second major problem which must be overcome by a practical artificial heart design is a simple and reliable control device for regulating blood flow and pressure in accordance with bodily requirements. Most all of the control designs proposed to date are relatively complicated electrical feedback systems utilizing complex metabolic sensing and monitoring devices. At the present time, all of the physiological parameters involved in the regulation of heart action are not known, and ineed the complexity involved in attempting to duplicate the natural control system is just being recognized. (Such difiiculties are discussed in the Hamilton Standard Final Report to the National Heart Institute, Feb. 11, 1966, page 196.)

No proposal to date has been advanced which suggest a practical system which may be powered and regulated by a patients chest and breathing muscles. Notably, at least one technical report to the National Heart Institute has stated that the use of skeletal muscle has shown to be infeasible. (Thermo Electron Engineering, Final Report, Artificial Heart Program, March 1966, page 25.) Nevertheless, it is through the use of a recipients chest and breathing muscles as a power source and means of regulation that the present invention achieves a practical, self regulated artificial heart system with a reliable and safe source of power.

SUMMARY OF THE INVENTION It is the object of this invention to provide an artificial heart system which may be completely implanted within and fully powered and regulated by a living, breathing body without external connections. This invention provides a pneumatically operated heart system which may totally replace the natural heart function or may be used as an assist device which by-passes all or a part of the natural heart. The artificial heart system disclosed herein requires no artificial source of power either external or internal but rather is fully powered and regulated by the chest and breathing muscles of the recipient body. As the means by which this system is powered will not become depleted, periodic maintenance to replace or reactivate the power source is not required. Surgery or other painful and health injuring procedures is thereby avoided. The artificial heart system provided herein is automatically responsive to the body needs of the patient providing 60 to 80 pumping strokes per minute at an average pumping volume of 5 liters per mintue. The artificial heart of the system is adapted to provide a pressure of 20 to 80 mm. of mercury to the pulmonary portion of the circulatory system and to provide a pressure of 120 to 180 mm.

of mercury to the systemic portion of the circulatory system. The artificial heart systems provided herein will generate a negligible amount of heat to be dissipated by the recipients body, the small amount of heat generated by this system being due to the volumetric inefficiency of the pneumatic pumping system. Further, the artificial heart systems described herein will minimize blood damage through mechanical shock by maintaining laminar flow during pumping and through the use of only two moving parts in the artificial heart, namely two plastic check ball valves. The artificial heart systems of this invention are preferentially provided with a means for introducing make-up air into the pneumatic system to replace gas lost by diffusion through the plastic walls of the pneumatic mechanism, the make-up air being provided thereby by the lungs of the patient or by gas injected into a suitable storage or make-up container located underneath the patients skin surface. A further advantage of the present invention is that little noise will be generated to remind the patient of his prosthesis. Such noise that is generated will be muffled by the body tissues surrounding the artificial heart system.

Briefiy stated, this invention is an artificial heart system for maintaining a normal blood circulation within a living, breathing body. The artificial heart system described herein is comprised of three elements, namely: (a) reciprocating pneumatic pump means for connection to a body for the production of pneumatic pressure in response to relative movements during breathing of the chest and breathing muscles, (b) an artificial heart connected to said pump means and to the circulatory system of the body for circulating blood through the circulatory system under pneumatic power received from said pump, and (c) control means operably connected between the pump means and the artificial heart for maintaining a proportion between the movements of the rib cage and the diaphragm and the rate of circulation powered by the artificial heart.

In one preferred form of this invention, the artificial heart is adapted to totally replace the natural heart of the body. In a second preferred form of this invention, the artificial heart is adapted to assist the natural heart of the body to maintain a normal blood circulation, the artificial heart being synchronized with the pumping action of the natural heart.

BRIEF DESCRIPTION OF THE DRAWINGS To aid in the understanding of this invention, the design and operation of two preferred forms are explained in detail below in conjunction with the accompanying drawmgs.

FIG. 1 represents oblique views of the two preferred embodiments of this invention.

FIG. 1a depicts an artificial heart comprised of a single blood pump for use as an assist to the left ventricle of the natural heart.

FIG. 1b depicts an artificial heart for total replacement of the natural heart. The total replacement heart is comprised of two blood pumps, one for the pulmonary system and the second for the systemic system.

FIG. 2 represents a schematic diagram of the pneumatic system utilized to supply pressure pulses to operate an artificial heart adapted for total replacement of the natural heart.

FIG. 3 represents in cross-section the left half of an artificial heart adapted for total replacement of the natural heart. In this figure, the artificial heart is depicted during the diastole stage of the pumping cycle, i.e. as pneumatic pressure is released from the central pneumatic sac 39 to cause it to contract and thereby induce blood into the surrounding pumping sac 38. The pneumatic control valve assembly 14, shown below the artificial heart in cross-section, is depicted in a condition to effect diastole.

FIG. 4 represents in cross-section the left half of the artificial heart and the control valve assembly 14 at the beginning of systole. During systole pneumatic pressure is introduced into the central pneumatic sac 39 to cause it to expand to fill the surrounding pumping sac 38 thereby expelling blood from the artificial heart.

FIG. represents in cross-section the left half of the artificial heart and the control valve assembly 14 at the end of systole. In the condition depicted the central pneumatic sac 39 has filled the surrounding pumping sac 38 thereby expelling substantially all of the blood from the artificial heart. In this condition, the fully expanded pneumatic sac presses against the outer cushion sac 42 thereby generating a pneumatic pressure pulse which triggers the control valve assembly 14 to begin diastole.

FIG. 6 represents in cross-section one half of an artificial heart for use as an assist to the left ventricle of the natural heart. The artificial heart as well as the pneumatic control valve assembly 73 shown in cross-section below the artificial heart are depicted during the diastole stage of the pumping cycle. A pneumatic sensing collar 82 disposed around the pulmonary artery 83 is actuated by the systolic pulses from the right ventricle of the recipients natural heart. The sensing collar in turn activates the pneumatic control valve assembly to effect synchronization between the patients heart and the artificial heart.

FIG. 7 depicts the implantation of the plural element reciprocating pump 1, its interconnection with the rib cage and diaphragm of the body and the relative positions of the rib cage during inspiration and expiration of breathing.

FIG. 8 illustrates the manner in Which the recipients circulatory system is interconnected with an artificial heart for total replacement of the natural heart.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First preferred embodiment Referring to FIGS. 2 and 3, a plural element reciprocating pump assembly, 1 is connected by artificial tendon 2 to the diaphragm of the patient and artificial tendon 3 connects the reciprocating pump to the rib cage. The plural element reciprocating pump is encased in a stainless steel container 4 to prevent growth of tissues in the thoracic cavity from interfering with pumping action. Pneumatic pulses generated by relative movement of the rib cage and diaphragm during breathing is conducted through line 5, through pump filter and drain 6 and thence through line 7 to a high pressure accumulator 8. Pump drain 6 filters condensation from the pressurized air from the pneumatic pump 1, if and when such condensation occurs, and the condensate is drained through a suitable check valve mechanism to line 9. Air is supplied through line 10 to the intake of the pneumatic pump 1 from the cushion chamber accumulator 11. Cushion chamber accumulator 11 is provided with a one-Way check valve 12 which supplies the cushion chamber accumulator 11 with make-up air from a small tube 12a inserted into one of the patients lungs, if air is used as the pressurizing means. If gas such as CO or 0 is used because of its ability to dissolve in the blood stream, then the make-up line 12a is terminated in a special cavity beneath the chest wall such that additional gas may be supplied by means of an injection through the skin.

High pressure from the high pressure accumulator 8 is supplied through line 13 to valve 20 of the pneumatic control valve assembly 14. The system is also provided with a low pressure accumulator 15 which is interconnected by lines 16 and 17 with the pneumatic control valve 14. High pressure accumulator 8 maintains a pressure of from 3.0 to 4.0 p.s.i. Low pressure accumulator 15 maintains a pressure from 2.0 to 3.0 p.s.i. The cushion accumulator 11 maintains a pressure from 1.0 to 2.0 p.s.i. The pneumatic control valve 14 simultaneously provides pneumatic pulses to the left blood pump 18 and the right blood pump 19 of the artificial heart assembly 31b. The pneumatic pulses for the left blood pump 18 supplied through line 32 and the pneumatic pulses for the right blood pump 19 being supplied through line 33. The pneumatic exhaust from the artificial heart assembly 31b to the pneumatic control valve 14 is provided by line 34 for the left blood pump 18 and line 35 for the right blood pump 19. The artificial heart system in effect operates to convert the 12 to 18 strokes per minute of the diaphragm or breathing muscles to 60 to pumping strokes per minute of the artificial heart pump. Pressure generated in pneumatic pump 1 in response to the action of the body breathing muscles develops high pressure in the range of 3 to 4 p.s.i. which is accumulated in the high pressure accumulator 8. The high pressure accumulator introduces high pressure into pneumatic control valve 14 which distributes the pneumatic pressure to the artificial heart 31b. The low pressure accumulator 15 retains pressure at 2 to 3 p.s.i. and the cushion chamber accumulator 11 retains pressure at from 1 to 2 p.s.i. The pneumatic control valve additionally supplies pulses of pneumatic pressure to the left and right blood pumps, the left blood pump 18 being actuated by pressure pulses supplied from the high pressure accumulator 8 and the right pneumatic blood pump 19 being operated by pressure pulses supplied from the low pressure accumulator 15. The low pressure accumulator 15 is charged by the exhaust pressure of the left blood pump 18-, and the cushion chamber 11 is charged by the exhaust pressure of the right blood pump.

The pumping cycle of the left blood pump 18 of the artificial heart 31b is depicted in FIGS. 3, 4 and 5. FIG. 3 depicts the condition of the left blood pump towards the end of diastole; FIG. 4 depicts the beginning of systole; and FIG. 5 depicts the end of systole. Referring to FIG. 3, the left blood pump 18 is depicted at the end of the pumping cycle, i.e. the end of diastole. The left blood pump 18 is supplied by an expandable reservoir sac 35 whose walls are expandable and contractable to prevent underfilling of the artificial ventricles and as well to prevent the formation of vapor bubbles in the blood due to a negative pressure that would be created during diastole of the blood pump. The expandable reservoir sac 35 is adapted for interconnection with a vein at inlet tube 36. An inlet tube 37 is connected with the fluid chamber 40 of left blood pump 18. The left blood pump 18 is comprised of a pumping sac 38 defining a pumping chamber 40. Disposed within the said fluid chamber 40 is a pneumatic sac 39 defining pneumatic chamber 41 which may be expanded to completely fill the fluid chamber 40 and thereby effect the pumping action. The fluid sac 38 is at least partially surrounded by pneumatic cushion sac 42 which defines the pneumatic cushion chamber 43. Pneumatic cushion sac 42 and fluid sac 38 are surrounded by a semi-rigid housing 44-. Pneumatic chamber 41 is provided with an inlet 45 and an outlet tube 46. A fluid chamber is provided with inlet tube 47 interconnecting with the outlet tube 37 of the expandable reservoir sac 35. The pumping sac 38 is additionally supplied with an outlet check valve 48 and outlet tube 49 adapted for interconnection with an artery. The cushion chamber is provided with an outlet tube 50.

The beginning of the artificial heart pumping cycle, i.e. the beginning of systole is depicted in FIG. 4. At this stage of the cycle, the pneumatic chamber outlet tube 46 is effectively blocked by pneumatic control valve assembly 14 while high pressure air from the high pressure accumulator 8 is introduced into the pneumatic chamber inlet 45. As the pressure in the pneumatic chamber 41 is increased, the pneumatic sac 39 expands to fill pumping chamber 40. It should be noted that at this stage of the pumping cycle the pneumatic sac 39 has expanded sufficiently to block off the inlet 47 to fluid chamber 40 and thereby the backward flow of blood into the expandable reservoir chamber 37 is prevented. As depicted in FIG. 4, the outlet ball check valve 48 is forced open during this part of the cycle to allow blood 7 to be expelled from fluid chamber 40 through outlet 49 and into an interconnected artery.

FIG. represents the stage of the pumping cycle at which pneumatic sac 39 has been completely expanded to fill the pumping chamber 40, i.e. the end of systole. The pneumatic sac 39 by expanding to completely fill fluid chamber 40 insures that blood is completely exhausted from the pumping chamber 40 during each pumping cycle and that thereby no stagnant blood is entrapped within the pumping mechanisms and allowed to deteriorate therein. At the end of systole, check ball valve 48 becomes seated in the fluid chamber outlet and closes the fluid chamber 40 off from back flow from the circulatory system. The ball check valve seats against the soft plastic material of the fluid chamber outlet 49 and is further cushioned by the air voids 130 in order to prevent damage to the blood by any sudden squeezing effect. Towards the end of systole the expanding pneumatic sac 39 forces itself against the wall of the pumping sac 38 and causes the pneumatic cushion sac 42 to collapse thereby forcing the air contained in cushion chamber 43 out through line 51 to the pneumatic control valve 14. The pressure introduced by 51 into the pneumatic control valve 14 forces the oscillating valve assembly to reposition itself in such a manner that the inlets to the pneumatic chambers of both the left and right blood pumps 18, 19 are shut off, the outlets to the pneumatic chambers of boh right and left blood pumps 18, 19 are opened and pneumatic pressure contained within the pneumatic chambers of both blood pumps are exhausted. The pneumatic pressure from the left blood pump is exhausted through control valve assembly 14 into the low pressure accumulator and the right blood pump is exhausted through control valve assembly 14 into the cushion accumulator 11.

The flow control unit 131 shown in FIG. 5 serves as a pneumatic time delay to assure total pumping action and complete evacuation of both right and left pneumatic chambers before the increased pressure in pneumatic cushion chamber 43 is transmitted through line 51 to the pneumatic control valve 14. One-way valve 132 maintains an air supply in the pneumatic cushion sac 43 whenever the pressure in the sac falls below that of the pneumatic cushion chamber 11. (The lowest ambient pressure that exists in pneumatic cushion chamber 43 throughout its cycle is that of the cushion chamber 11.)

The regulation and control of the pumping action in this system is provided by virtue of the fact that the body breathing rate varies in accordance with the bodily requirement for oxygen. As the bodily requirement increases the breathing rate also increases thereby developing a greater force to actuate the reciprocating pneumatic pump 1 with the result that the pneumatic pressure supplied to the artificial heart system is increased. The increased pressure in the system increases the pumping rate of the artificial heart and greater power is developed in each pumping stroke. In like manner, as the bodily oxygen demand is decreased, the body breathing rate also decreases causing a reduction in the pumping rate and power developed by the artificial heart. In this manner, the artificial heart system accomplishes self-regulation that is fully responsive to the physiological requirements of the patient.

Second preferred embodiment FIG. 6 illustrates a second preferred embodiment of this invention in which a single artificial heart pump 31a is used as a ventricular assist to assist a weakened natural heart by aiding or wholly replacing the pumping action of the natural hearts left ventricle which performs the majority of the pumping work in the human heart.

The artificial heart assist system depicted in FIG. 6 is similar in construction and function of the system described above for total replacement. Blood is introduced from the pulmonary vein into an inlet tube 60 of an expandable reservoir sac 61. The function of the expandable reservoir sac 61 is to expand and contract and thereby maintains a pressure at all times upon the blood above its vapor pressure at the ambient temperature. Blood travels from the reservoir sac 61 to the reservoir exit tube 62 and into the inlet of the pumping chamber 65. Blood is pumped from the inlet 64 through the pumping chamber 65 and exits through the ball check valve 66 to the pumping chamber exit tube 67 which is interconnected with the patients ascending aorta. In this manner the patients left ventrical is by-passed and the effort of the patients heart is directed to pumping blood into the right ventricle of the natural heart.

As is the case in the total implanted system, the ventricle assist blood pump is comprised of a pumping sac 68 defining a fl'uid chamber 65 in which is located an expandable pneumatic sac 69 defining the pneumatic chamber 70. The pneumatic chamber 70 is provided with an inlet 71 which connects through line 72 to the pneumatic pressure control valve 73, said pneumatic control valve functioning in a manner similar to control valve 14 of the total replacement system. The inlet tube is adapted to receive high pressure from the pneumatic control valve 73 which causes the inflation of the pneumatic sac 69. The inflation of the pneumatic air sac provides the pumping function of the blood pump by expanding to completely fill the fluid chamber 65 and thereby gently forcing the blood content in the fluid chamber out through ball check valve 66 and to the ascending aorta.

The pneumatic air chamber 70 is additionally supplied with an exit tube 74 which connects by line 75 to the pneumatic pressure control valve 75 whereby the pneumatic chamber is exhausted during the diastole portion of the pumping cycle through the pneumatic control valve to cause collapse of the pneumatic sac 69 and thereby places the blood pump 31a in condition for another pumping stroke.

As is the case of the total implanted system, the fluid sac is at least partially surrounded by a pneumatic cushion sac 76 defining a pneumatic cushion chamber 78 which has the function of cushioning the shock of the pumping action of the pneumatic sac. The pneumatic cushion chamber 78 connects by means of exit 79 through line 80, and a one-way valve 134 to cushion chamber accumulator 81.

The control and regulation of the pumping action is provided by pneumatic sensing collar 82 which fits around the neck of the pulmonary artery 83. Systole of the patients natural heart causes the pulmonary artery to expand and thereby constrict the pneumatic sensing collar 82 to generate a pneumatic pulse. The pneumatic pulse from sensing collar 82 is conveyed through line 84 to the flow control valve 133 to actuate diaphragm 135 and thereby cause the conical valve head 136 to become unseated. When the flow control valve 133 is in this condition a pneumatic pressure pulse generated by cushion chamber 78 (as the blood pump 31a reaches the end of systole) will freely pass through line and the flow control valve 133 into chamber 126 to trigger the pneumatic control valve 73 to effect diastole of the artificial heart. In this manner, the pumping cycle of blood pump 31a is synchronized with the action of the patients natural right ventricle.

As in the total implanted system, the artifical heart system is powered by a pneumatic pump 85 encased in a stainless steel case 86 which is activated by the relatively reciprocating motion of the patients rib cage and diaphragm by means of artificial tendon 87 connected to a rib and artificial tendon 88 connected to the patients diaphragm. High presure pulses from the pneumatic pump 85 are sent through line 89 to filter 90 which filters condensate from the pressurized air, such condensate being led from filter 90 through line 91. Filtered pressurized pulses travel from filter 90 through line 92 to the high pressure accumulator 93. The high pressure from the accumulator travels through line 95 to the high pressure inlet valve 96 of the pneumatic control valve 73. The

exhaust from the pneumatic chamber travels through line to the pneumatic control valve 73 and there to the cushion accumulator chamber 81. The pneumatic pressure is recycled from cushion chamber 81 to the intake of the pneumatic pump 85. Make-up air is provided through line 99 which provides make-up air from the patients lung to replace air which may be lost over long periods by leakage through the pores of the plastic walls of the various components of the artifical heart system.

DESCRIPTION OF THE METHOD OF IMPLANTATION FIG. 7 illustrates the implantation of the pneumatic pump for both total replacement and assist systems. The pneumatic pump 100 is located within the thoracic cavity 101 defined by the rib cage 102 and diaphragm 103. The pneumatic pump 100 is connected by means of an artificial tendon 104 to a rib 105 and is also connected by means of a second artifical tendon 106 to the diaphragm 103. Advantageously, tendon 106 is attached to the diaphragm 103 by means of a stainless steel Wire reinforced Dacron web 107 which is sewn to the diaphragm at 107a. The junction of the diaphragm to the chest wall is separated by a narrow plastic lining 10722 to prevent the formation of adhesions. The stainless steel wire reinforced Dacron web 107 used to harness the diaphragm is woven into the small diameter artifical tendon 106. The same construction is utilized to manufacture the second artifical tendon 104.

Reference numbers 102 and 102' represent the relative location of the rib cage during inspiration and expiration, respectively. In like manner, reference numbers 103 and 103 represent the relative location of the diaphragm during inspiration and expiration, respectively. In FIG 7b, the relative location of the artifical tendons 104 and 106 and the pneumatic pump 100 are shown during inspiration.

FIG. 8 represents the manner in which the recipients circulatory system is interconnected with an artifical heart for total replacement of the natural heart. FIG. 108 represents in cross-section a natural heart which is removed for total implantation of the artifical heart system. FIG. 109 represents in cross-section the aortic arch which is connected by a suitable sleeve 110 of an inert woven plastic such as Dacron for connection to the outlet of the left blood pump 18 of the artifical heart. The pulmonary veins 111 likewise are connected by means of an inert woven plastic sleeve 112 to the expandable reservoir sac of the left blood pump 18. The superior and vena cava 114 are connected by sleeve 115 to the inlet of the expandable reservoir sac of the right blood pump 19. The pulmonary arteries are connected by sleeve 116 to the outlet of the right blood pump 19. By this means, the entire circulatory system of the patient is interconnected with the artifical heart to effect a total replacement of the function of the natural heart.

DESCRIPTION OF THE OPERATION OF THE PNEUMATIC CONTROL VA-LVES The operation of the two pneumatic control valve assemblies 14 and 73 described above can be best explained by describing first the operation of the pneumatic control valve assembly 73 for the artifical heart system depicted by FIG. 6. In FIG. 6, the pneumatic control valve 73 is shown to be comprised of a housing 118, a control rod 119 which is allowed limited horizontal movement, and three pressure sealing diaphragms 120, 121 and 122, all operably connected to the control rod 119. In addition, there are four pneumatically sealed chambers identified by reference number 123, 124, 125 and 126 which are defined by the housing 73 and three pneumatically sealed diaphragms 120, 121 and 122. The control rod 119 is provided with ball valve heads 96 and 127 which are adapted to seat against valve orifices 128 and 129. The control rod 119 is spring loaded by spring 130 which tends to force the rod into position as depicted in FIG. 6. In the condition depicted by FIG. 6, valve orifice 128 is open to allow pneumatic pressure from the high pressure accumulator 93 to pass through chamber 123 to line 72 and then to pneumatic chamber 70 of the artifical heart. In the condition depicted by FIG. 6, valve orifice 129 is closed with ball valve head 127 seated thereby blocking exhaust from the exit 74 of the pneumatic chamber 70. In this condition, the pneumatic control valve assembly 73 effects systole by expanding pneumatic sac 69 under pneu matic pressure supplied from the high pressure accumulator 93.

As the right ventricle of the natural heart effects systole, the expansion of the pulmonary artery 83 will cause the pneumatic sensing collar 82 to generate a pneumatic pulse which is conveyed through line 84 to flow control valve 133 to actuate diaphragm 135 and thereby cause the conical valve head 136 to become unseated. In this condition, a pneumatic pulse from cushion chamber 78 will freely pass through line 80 and the flow control valve 133 into chamber 126 of the pneumatic control valve 73. As explained above, when pneumatic sac 69 has expanded to fill pumpng chamber 65 at the end of systole, the pneumatic sac presses against cushion sac 76 and thereby generates a pneumatic pulse. The pneumatic pulse from cushion chamber 78 when synchronized with systole of the right ventricle of the natural heart will be conveyed to pneumatic chamber 126 of the control valve assembly and operate against the pneumatic diaphragm 122 to force the control rod assembly into a position to effect diastole.

When control valve 73 is in condition to effect diastole, the control rod 119 is positioned so that ball valve 96 is seated against valve orifice 128 thereby stopping the flow of high pressure to the pneumatic chamber 70. Ball valve head 127 is unseated and pneumatic pressure in pneumatic chamber 70 may freely exhaust through valve orifice 129 to cushion chamber 81.

When in an open condition, conical valve head 136 acts as a pneumatic time delay which delays the build up of pneumatic pressure in pneumatic chamber 126. By providing this time delay, the pneumatic sac 69 is allowed to fully expand within the pumping chamber 65. The time delay action of conical valve head 136 also acts to delay the release of pressure from pneumatic chamber 126 as the pneumatic sac 69 contracts and the pressure in the cushion chamber 78 returns to that of the cushion chamber 81. In this manner, by a careful adjustment of the amount of travel of the conical valve head 136 when it is opened by pressure applied to pneumatic diaphragm 135, the diastolic and systolic rates of the blood pump may be adjusted.

The control valve assembly 14 for the total replacement artificial heart system operates in essentially the same manner. The major difference between the two control -valve assemblies 14 and 73 is that control valve assembly 14 operates two blood pumps 18 and 19 rather than one. Control valve assembly 14 comprises a housing 137, a control rod 138, five pneumatically sealed diaphragms 139, 140, 141, 142 and 143, all connected to control rod 138, and four ball valve heads 20, 144, 145 and 146 disposed along the control rod 138 which are adapted to seat against valve orifices 148, 149, and 151. The five pneumatic diaphragms in the housing 137 define eight pneumatically sealed chambers 152, 153, 154, 155, 156, 157, 158 and 159. Spring 147 acts against rod 138 to force the control rod into position depicted in FIG. 2. In this position, valve orifices 148 and 150 are open to allow pneumatic pressure to enter the pneumatic chambers of both left and right blood pumps of the artificial heart. Valve heads 144 and 146 are seated against their respective valve orifices 149 and 151 to block the exit tubes of the pneumatic chambers of both right and left blood pumps. In this condition, the control valve 14 affects systole by expanding the pneumatic sacs of both 1 1 blood pumps 18 and 19 to fill the pumping chambers and thereby expel blood from the artificial heart to the interconnected arteries.

As the artificial heart 31b reaches the end of systole, the cushion chamber 43 of the left blood pump 18 generates a pneumatic pulse which is conveyed through line 51 to flow control valve 131 and then to pneumatic chamber 159 to actuate pneumatic diaphragm 143. The flow control valve assembly 131 is provided with an adjustable truncated conical valve head 160 which provides for a time delay in the build up of the pneumatic pressure from cushion chamber 43 actuating pneumatic diaphragm 143. When the left blood pump 18 reaches the end of systole, the pneumatic pressure in chamber 159 reaches a sufficient value to drive the control rod 138 into a position in which valve heads 20 and 145 are seated against valve seat orifices 148 and 150 thereby terminating the flow of pneumatic pressure through both the pneumatic chambers of the artificial heart 3112. In this position orifice valves 144 and 146 are open to allow the exhaust of pneumatic pressure from the two pneumatic chambers of the artificial heart 31b. As both pneumatic chambers contract and the pressure in cushion chamber 43 of the left blood pump returns to a value equal to the pressure in the cushion chamber 11, pneumatic pressure in pneumatic pressure chamber 159 passes through fiow control valve 131 to the cushion chamber. Flow control valve 131 during this phase of the pumping cycle also acts as a time delay in the release of pneumatic pressure from pneumatic chamber 159 whereby the control valve rod 138 is held in a position for a suflicient length of time to completely effect diastole. The degree of obstruction presented by control valve head 160 is adjustable by means of turn screw 161 whereby the diastolic and systolic rates of the artificial heart system may be adjusted.

VOLUMETRIC AND ENERGY REQUIREMENTS OF THE PREFERRED EMBODIMENTS The various components of the artificial heart systems described above are sufiiciently light and have a sufiiciently small volumetric displacement for implantation in the pericardial and thoracic cavities of the recipient body. The artificial heart and the pneumatic control valve assembly are adapted to be implanted in the pericardial cavity. The various pneumatic accumulators, which are adapted to implantation in the thoracic cavity, all have specific gravities less than 1.0 and therefore need not be supported. The volumetric displacement of the high pressure accumulator is approximately 100.0 cubic inches. The low pressure accumulator will displace 75.0 cubic inches, and the cushion chamber accumulator will displace 50 cubic inches.

The energy required to operate the various artificial heart systems described above is provided by the muscular energy of the patients diaphragm. The human diaphragm develops on the average 21.7 ft.-lbs. of work per stroke during relaxed breathing and 54.4 ft.-lbs. of work per stroke during heaving breathing. For total replacement the artificial heart system will require 6.2 ft.- lbs. of energy per stroke. An artificial heart system to assist or replace the function of the left ventricle of the natural heart will require 2.57 ft.-lbs. of energy er stroke. Therefore, the diaphragm muscles of the recipient will readily adapt to the additional effort required to power an implanted artificial heart system and the interference to normal body breathing will be minor.

The above disclosure and particularly the two preferred embodiments set forth therein are by way of illustration only and are not intended to limit the scope of the invention described herein. Other working media than a compressible pneumatic gas may be used advantageously, for example, a relatively incompressible hydraulic fluid. It should be obvious to one skilled in the art that many modifications and variations may be made upon the artificial heart system disclosed above without departing from the spirit and the scope of the invention.

I claim:

1. An artificial heart system for maintaining a normal blood circulation within a living, breathing body at a variable rate according to the requirement of the body comprising:

(a) reciprocating pneumatic pump means for connection to a body for the production of pneumatic pressure in response to relative movements of the chest and breathing muscles during breathing,

(b) an artificial heart connected to said pump means and adapted to be connected to the circulatory system of the body for circulating blood through the circulatory system under pneumatic power received from said pump, and

(c) control means operably connected between the pump means and the artificial heart for maintaining a proportion between the relative movements of the chest and breathing muscles and the rate of circulation powered by the artificial heart.

2. An artificial heart system described by claim 1 in which:

(a) the artificial heart is comprised of an inert flexible plastic material defining a plurality of chambers adapted to receive blood from at least one interconnected vein and to pump said blood to at least one interconnected artery, said chambers comprising at least one reservoir chamber interconnected with one pumping chamber, said reservoir chamber adapted to receive blood from an interconnected vein and to deliver said blood to the pumping chamber at a pressure suificiently greater than the vapor pressure of the blood, said pumping chamber operable to alternately receive a quantity of blood from the reservoir chamber and expel said glood to an interconnected artery in response to the alternate receipe and release of pneumatic pressure supplied to the artificial heart from the control means, said pumping chamber expelling blood upon the receipt of pneumatic pressure and receiving blood upon the release of said pneumatic pressure.

(b) the control means comprises a plurality of pneumatic pressure accumulators for supplying pneumatic pressure to the artificial heart and receiving pneumatic pressure released therefrom and a control valve assembly positioned between said pneumatic pressure accumulators and the artificial heart for controlling the supply and release of pneumatic pressure for the artificial heart to thereby operate said pumping chambers, a first and a second of said accumulators being positioned between the reciprocating pneumatic pump means and the control valve assembly, said first accumulator interconnected with the reciprocating pneumatic pump means and the control valve assembly and thereby adapted to be charged with pneumatic pressure produced by the pneumatic pump means and to supply pneumatic pressure to the pneumatic control valve assembly, said second accumulator interconnected with the control valve assembly and the reciprocating pneumatic pump means and thereby adapted to be charged with pneumatic pressure released from the control valve assembly and to supply pneumatic pressure to the pneumatic reciprocating pump means, said pneumatic control valve assembly comprising a plurality of valve means 0perable in unison at a rate proportional to the value of the pneumatic pressure supplied by said first accumulator, said valve means operating to alternately supply and release pneumatic pressure for the artificial heart and thereby operate the pumping chambers, and

(c) the reciprocating pneumatic pump comprises a plurality of elements, a first element of said reciprocating pneumatic pump having means for connection to the rib cage of the body and a second element having means for connection to the diaphragm of the body, said connecting means adapted to reciprocate said pump elements upon relative movement of the rib cage and diaphragm during inspiration and expiration of breathing of the body, said pneumatic pump supplying pneumatic pressure to said first accumulator upon inspiration of the body at a value dependent upon the frequency and force of relative movements of the rib cage and diaphragm during inspiration of breathing, whereby variable pumping rate of the artificial heart is attained according to the requirement of the body by maintaing a proportion between the rate of body breathing, the value of pneumatic pressure supplied to the high pressure accumulator, and the rate at which the control valve assembly alternately supplies and releases pressure for the pneumatic chambers of the artificial heart.

3. An artificial heart system described in claim 2 in which:

(a) the artificial heart is adapted to generate a pres sure pulse as one of the pumping chambers expels blood to an interconnected artery, said artificial heart provided with means to deliver said pneumatic pressure pulse to the control valve assembly, and

(b) the pneumatic pressure control valve assembly is adapted to be actuated by said pneumatic pressure pulse to release pneumatic pressure from the artificial heart to cause the pumping chambers of the artificial heart to receive blood from the interconnected reservoir chambers, said control valve assembly adapted to alternately supply and release pneumatic pressure for the artificial heart and thereby effect variable control of the pumping rate of the artificial heart according to the requirements of the body.

4. An artificial heart system described by claim 3 in which:

(a) a flow control valve is operably connected between the artificial heart and the control valve assembly, said flow control valve operable to control the value of the pneumatic pressure pulse delivered to the control valve assembly from the artificial heart as one of the pumping chambers expels blood to an interconnected artery, and

(b) a pneumatic sensing collar adapted to be disposed around the pulmonary artery of the body and adapted to generate a pneumatic pressure pulse as said pulmonary artery expands during systole of the right ventricle of the natural heart of the body, said pneumatic sensing collar provided with means to deliver said pneumatic pressure pulse to the flow control valve, said flow control valve actuated by a pneumatic pressure pulse from the sensing collar to allow a sufiicient value of pneumatic pulses from the artificial heart to be delivered to the control valve assembly which is actuated thereby to release pressure from the artificial heart to cause the pumping chambers of the artificial heart to receive blood from the interconnected reservoir chambers,

whereby the pumping action of the artificial heart is synchronized with the natural heart of the body by means of pneumatic pressure pulses supplied to the flow control valve from the pneumatic sensing collar.

5. An artificial heart system described by claim 3 in which the artificial heart is comprised of a first reservoir chamber interconnected with a first pumping chamber and a second reservoir chamber interconnected with a second pumping chamber, said artificial heart being adapted to be interconnected with the circulatory system of the body with the first reservoir chamber interconnected with the inferior and superior vena cava and the first pumping chamber interconnected with the pulmonary artery, the second reservoir chamber interconnected with the pulmonary vein and the second pumping chamber interconnected with the aortic arch, said artificial heart adapted to generate a pressure pulse when blood is substantially expelled from the pumping chambers, said artificial heart provided with means to deliver said pneumatic pressure pulse to the control valve assembly, whereby the artificial heart totally replaces the natural heart of the body and maintains a normal blood circulation in the circulatory system according to the requirement of the body.

6. An artificial heart system described by claim 4 in which the artificial heart is comprised of a one reservoir chamber interconnected with one pumping chamber, said artificial heart adapted to be interconnected with the circulatory system of the body with said reservoir chamber interconnected with the pulmonary vein and the pumping chamber interconnected with the ascending aorta, whereby the artificial heart assists the natural heart of the body to maintain a normal blood circulation in the circulatory system, said artificial heart being synchronized with the pumping action of the natural heart by means of pneumatic pressure pulses supplied to the control valve assembly from the pneumatic sensing collar.

7. An artificial heart system described by claim 5 in which:

(a) the artificial heart is comprised of:

(i) a first expandable reservoir sac defining a first reservoir chamber interconnected with a first blood pump defining a first pumping chamber, a first pneumatic chamber and a first cushion chamber,

(ii) a second expandable reservoir sac defining a second reservoir chamber interconnected with a second blood pum defining a second pumping chamber, a second pneumatic chamber and a second cushion chamber,

said pneumatic chambers adapted to receive pneumatic pressure from the control valve assembly to expel blood contained within said pumping chambers, said pneumatic chambers further adapted to release pneumatic pressure to the control valve assembly to allow said pumping chambers to re ceive blood from the interconnected reservoir chambers, said first cushion chamber adapted to generate a pressure pulse when blood is substantially expelled from the pumping chamber, said first cushion chamber provided with means to deliver said pneumatic pressure pulse to the control valve assembly,

said artificial heart being adapted to be interconnected with the circulatory system of the body with the second reservoir chamber interconnected with the inferior and the superior vena cava and the second pumping chamber interconnected with the pulmonary artery, the first reservoir chamber interconnected with the pulmonary vein and the first pumping chamber interconnected with the aortic arch,

(b) the control means is comprised of:

(i) a high pressure accumulator interconnected with the reciprocating pneumatic pump means and the control valve assembly and thereby adapted to be charged with pneumatic pressure produced by the pneumatic pump means and to supply pneumatic pressure to the pneumatic control valve assembly to operate said first pneumatic chamber,

(ii) a low pressure accumulator interconnected with the control valve assembly and thereby adapted to be charged with pneumatic pressure from the first pumping chamber and to supply pneumatic pressure to the second pneumatic chamber,

(iii) a cushion chamber accumulator interconnected with the reciprocating pneumatic pump means and the control valve assembly and thereby adapted to be charged with pneumatic pressure from the second pneumatic chamber and to supply pneumatic pressure to the pneumatic reciprocating pump means,

(iv) a control valve assembly interconnected with said accumulators, said pneumatic chambers, and the first cushion chamber, said pneumatic control valve assembly comprising a plurality of valve means operable in unison at a rate proportional to the valve of the pneumatic pressure supplied by the high pressure accumulator, said pneumatic pressure control valve assembly adapted to be actuated by a pneumatic pressure pulse from the first cushion accumulator to release pneumatic pressure from the pneumatic chambers, said control valve means operating to alternately supply and release pneumatic pressure for the pneumatic chambers and to thereby operate the pumping chambers, and

(c) the reciprocating pneumatic pump comprises a plurality of elements, a first element of said reciprocating pneumatic pump having means for connection to the rib cage of the body and a second element having means :for connection to the diaphragm of the body, said means adapted to reciprocate said pump elements upon relative movement of the rib cage and diaphragm during inspiration and expiration of breathing of the body, said pneumatic pump supplying pneumatic pressure to said first high pressure accumulator upon inspiration of the body at a value dependent upon the frequency and force of relative movements of the rib cage and diaphragm during inspiration of breathing,

whereby variable pumping rate of the artificial heart is attained according to the requirement of the body by maintaining a proportion between the rate of body breathing, the value of pneumatic pressure supplied to the high pressure accumulator, and the rate at which the control valve assembly alternately supplies and releases pressure for the pneumatic chambers of the artificial heart.

8. An artificial heart system described by claim 6 in which:

(a) the artificial heart is comprised of an expandable reservoir sac defining a reservoir chamber interconnected with a blood pump defining a pumping chamber, a pneumatic chamber and a cushion chamber, said pneumatic chamber adapted to received pneumatic pressure from the control valve assembly to expel blood contained within said pumping chamber, said pneumatic chamber further adapted to release pneumatic pressure to the control valve assembly to allow said pumping chamber to receive blood from the interconnected reservoir chamber, said cushion chamber adapted to generate a pressure pulse when blood is substantially expelled from the pumping chamber, said cushion chamber being provided with means to deliver said pneumatic pressure pulse to the control valve assembly, said artificial heart adapted to be interconnected with the circulatory system of the body with said reservoir chamber interconnected with the pulmonary vein and the pumping chamber interconnected with ascending aorta,

(b) the control means comprises:

(i) a high pressure accumulator interconnected with the reciprocating pneumatic pump mean. and the pneumatic control valve assembly and thereby adapted to be charged with pneumatic pressure produced by the pneumatic pump means and to supply pneumatic pressure to the pneumatic control valve assembly to operate the pnematic chamber,

(ii) a cushion chamber accumulator interconnected with the reciprocating pneumatic pump means and the control valve assembly and thereby adapted to be charged with pneumatic pressure supplied by the control valve assembly from the pneumatic chamber and to supply pneumatic pressure to the pneumatic reciprocating pump means,

(iii) a flow control valve assembly operably connected between the artificial heart and the control valve assembly, said flow control valve operable to control the value of the pneumatic pressure pulses delivered to the control valve assembly from the artificial heart as the pumping chamber exepels blood to the ascending aorta,

(iv) a pneumatic sensing collar adapted to be disposed around the pulmonary artery of the body and adapted to generate a pneumatic pressure pulse as said pulmonary artery expands during systole of the right ventricle of the natural heart of the body, said pneumatic sensing collar provided with means to deliver said pneumatic pressure pulse to the flow control valve, said flow control valve actuated by a pneumatic pressure pulse from the sensing collar to allow a sufficient value of pneumatic pulses from the artificial heart to be delivered to the control valve assembly which is actuated thereby to release pressure from the artificial heart to cause the pumping chambers of the artificial heart to receive blood from the interconnected reservoir chambers,

(v) a control valve assembly interconnected with said accumulators, the artificial heart and the flow control valve, said control valve assembly comprising a plurality of valve means operable in unison at a rate synchronized with the pumping rate of the natural heart, said control valve assembly adapted to be actuated by pneumatic pressure pulses from the cushion chamber of the artificial heart to thereby cause the control valve assembly to release pressure from the pneumatic chamber and thereby allow the pumping chamber to receive blood from the interconnected reservoir chamber, said valve means operating to alternately supply and release pneumatic pressure for the artificial heart and thereby operate the pumping chambers,

(c) the reciprocating pneumatic pump comprises a plurality of elements, a first element of said reciprocating pneumatic pump having means for connection to the rib cage of the body and a second element having means for connection to the diaphragm of the body, said means adapted to reciprocate said pump elements upon relative movement of the rib cage and diaphragm during inspiration and expiration of breathing of the body to thereby supply pneumatic pressure to the high pressure accumulator,

whereby the artificial heart assists the natural heart of the body to maintain a normal blood circulation in the circulatory system, said artificial heart being synchronized with the pumping action of the natural heart by means of pneumatic pressure pulses supplied to the flow control valve from the pneumatic sensing collar.

9. In the artificial heart system described by claim 7,

an artificial heart comprising:

(a) a first expandable reservoir sac defining a first reservoir chamber interconnected with a first blood pump defining a first pumping chamber, a first pneumatic chamber and a first cushion chamber,

(b) a second expandable reservoir sac defining a second reservoir chamber interconnected with a second 3,518,702 17 18 a blood pump defining a second pumping chamber, a 10. In the artificial heart system described by claim 8, second pneumatic chamber and a second cushion an artificial heart comprising: chamber, (a) an expandable reservoir sac defining a reservoir (c) each expandable reservoir sac comprising an inert chamber interconnected With a blood P p flexible plastic defining a reservoir chamber provided fining a pumping chamber, a pneumatic chamber with an inlet tube and an outlet tube, the inlet tube and a cushion adapted to interconnection with the vein and the outthe expandable tesetvoll' See eetniltlslng a fleXlhte let tube communicating the reservoir chamber with inert D n e definlng a feSeYVOn' Chamber P the pumping chamber f the blood pump, i reset. vlded with an lnlet tube and an outlet tube, the inlet voir chamber adapted to maintaining a pressure upon tube adapted to lntereonneetlon With a e and the blood contained therein at a sufficient value so that ohtlet tube eemmunleatlng the reSeWOn' Phamhef when pumped by the pneumatic pump the blood will wltth the pumplng ehalnhel 0f the pnenlnatte PP nP b maintained at a pressure greater than its vapor said expandable reservolr sac adapted to ma1nta1n1ng pressure a pressure upon blood contained there1n at a suf- (d) each 6 Said blood pumps comprising: ficient value so that when pumped by the blood pump (i) a pumping sac adapted to receive blood from the blood Will be maintained at a pressure greater an interconnected reservoir chamber and to than Its vapor pressure deliver said blood to an interconnected artery, (e) e bleed h eemptlsmgt said pumping sac comprising an elongated inert (1) a PumPlhg See adapted e l'eeelve blood from fl ibl plastic Sac defining the pumping chamber an interconnected reservoir chamber and to and provided at one end with an inlet eoinninnh deliver said blood to an nterconnected artery, cating with the outlet of the interconnected exp p g ac c mprislng an elongated flexpandable reservoir sac and an outlet at the oplble lhert Plastle See e e P P e h posite end Provided with an inert pinstic hail provided at one end with an inlet communicating check valve communicating with an outlet tube Wlth the Outlet of an expendable reservon' e adapted to interconnection with an artery, and an outlet at the opposite end provided with (ii) an expandable pneumatic sac located within h Inert Plastte hell cheek Valve eemmumeatmg Said pumping chamber and adapted to reeeive w th an outlet tube adapted to be lnterconnected and release pneumatic pressure to elfect pumpan artery, ing of the hiood contained within the Pnniping 3O (11) an expandable pneumatic sac located withln chamber, said pneumatic sac comprising an ex- Seld P P Chamber and adapted to receive pandable inert plastic sac defining a pneumatic e release Pneumetle P e t etteet P hP- chamber provided with an inlet tube at the inlet 8 of the hteed eentatned Wlthm he pumplng end of the pumping sac and an outlet tube at chamber, Sa1d p matlc Sac comprismg an exthe outlet end of the pumping sac, said inlet pandable Inert plastle see eefinlng a pnenlnatle and outlet tnhes Comninnicating tho nnonnmtic chamber provlded with an inlet tube at the lnlet chamber with the control valve assembly, said end of the Pumplhg See t an outlet t e at pneumatic sac adapted to expand to fill the the outlet end of the Ph Pt Sate lhlet pumping chamber by the introduction of nnen and outlet tubes communlcatmg the pneumat c matic pressure into the pneumatic chamber so 40 ehambehwlth the control Valve assembly, Sald that blood contained in the pumping chamber Pheuthehe see adapted e P e to ml the is expelled from the pumping chamber through P hP chamber by the mtteduettoh 0t P the bail cheek valve at the pumping chninher matic pressure into the pneumatrochamber so outlet, said pneumatic sac adapted to contract t hlood eohtathed 1h P P chamber from an expanded condition by the release dhlfeh from h PuthPlhg chamber of pnenmatic pressure from the pneumatic let, said pneumatic sac adapted to contract chamber so that blood contained in the reservoir from an exhended eenthtlen y the release chamber is induced into the pumping chamber, of Pheumette Pressure h the P e (iii) a cushion one at least partially Surrounding chamber so that blood contained 1n the reservoir said pumping sac and adapted to pneumatically e Induced Into the ptlmplhg chamber, cushion the pumping aetion of the pneumatic (111) a cushlon sac at least partially surroundlng sac, said cushion sac comprising an expandable 531d Pumplhg see e adapted to Pheumetleahy inert plastic sac defining a cushion chamber ehshleh the P t P See t adapted to P and adapted to being compressed to thereby thaheahY eushlon, the Ph P eehen e the generate a pneumatic pressure pulse as the pneu- Pneumttt1c e stud ehehleh See eempnslhg an matic sac expands to fill the pumping chamber, expendable lhett Plastle e definmg e P e Said Pneumatic cnshion Sac provided with an mat1c cushion chamber, said pneumatic cushion exit tube communicating with the cushion Sac adapted to compressed to thereby chamber, the cushion chamber exit tube for generate a Pheumatle Pressure Pulse as t the second blood pump for interconnection with Pneumatlc e expand? to h the PumPmg the cushion chamber accumulator and the cushh j Pneumatlc cushlon Sac Provlded ion chamber exit tube for the first blood pump wlth an .exlt mp6 adapted to eommumcate the for interconnection with the pneumatic Prespmaiumtitlc clillshlon cham-ber wlth the flow consure control valve assembly the pneumatic no Va t e pneumatlc pressure plilse frqm 5 the cushion chamber, when synchronized with pressure pulses from the first cushlon chamber a pneumatic pressure pulse from the pneumatic controlllng the action of the control valve as- Sensing collar, actuating the control valve sembly to actuate the control valve assembly to sembly to release pneinnntic pressure from the relense Pneumatle Pressure from both P pneumatic chamber of the artificial heart, matic chambers, (iv) a housing of semi-rigid plastic at least par- (iv) a housing of inert semi-rigid plastic at least tially surrounding said cushion sac and said partially surrounding said cushion sac and said pumping sac, said housing adapted to confine pumping sac, said housing adapted to confine the expansion of both the pneumatic cushion sac the expansion of both the cushion sac and the and the P p pumping sac. 11. In an artificial heart system described by claim 1,

a pneumatic pump for powering a pneumatically operated artificial heart comprising a plurality of elements, a first element of said reciprocating pneumatic pump having means for connection to the rib cage of the body and a second element having means for connection to the dlaphragm of the body, said means adapted to reciprocate said pump elements upon relative movement of the rib cage and diaphragm during inspiration and expiratlon of breathing of the body, said pneumatic pump supplying pneumatic pressure to the artificial heart upon lnspiration of the body at a rate dependent upon the frequency and force of relative movements of the rib cage and diaphragm during inspiration of breathing.

12. In an artificial heart system described by cla m 1,

a means for powering a pneumatically operated artificial heart comprising:

(a) a control means comprised of a plurality of pneumatic pressure accumulators for supplying pneumatic pressure to the artificial heart and receiving pneumatic pressure released therefrom and a control valve assmebly positioned between said pneumatic pressure accumulators and the artificial heart for controlling the supply and release of pneumatic pressure for the artificial heart to thereby operate said artificial heart, a first and a second of said accumulators being positioned between a reciprocating pneumatic pump and the control valve assembly, said first accumulator interconnected with the reciprocating pneumatic pump means and the control valve assembly and thereby adapted to be charged with pneumatic pressure produced by the pneumatic pump means and to supply pnuematic pressure to the Pneumatic control valve assembly, said second accumulator interconnected with the control valve assembly and the reciprocating pneumatic pump means and thereby adapted to be charged with pneumatic pressure released from the control valve assembly and to supply pneumatic pressure to the pneumatic reciprocating pump, said pneumatic control valve assembly comprising a plurality of valve means operable in unison at a rate proportional to the valve of the pneumatic pressure supplied by said first accumulator, said valve means operating to alternately supply and release pneumatic pressure for the artificial heart and thereby operate said artificial heart, and

(b) a reciprocating pneumatic pump comprised of a plurality of elements, a first element of said recip rocating pneumatic pump having means for connection to the rib cage of the body and a second element having means for connection to the dia hragm of the body, said means adapted to reciprocate said pump elements upon relative movement of the rib cage and diaphragm during inspiration and expiration of breathing of the body, said pneumatic pump supplying pneumatic pressure to said first pressure accumulator upon inspiration of the body at a value dependent upon the frequency and force of relative movements of the rib cage and diaphragm during inspiration of breathing,

whereby variable pumping rate of the artificial heart is attained according to the requirement of the body by maintaining a proportion between the rate of the body breathing, the value of pneumatic pressure supplied to the pressure accumulator, and the rate at which the control valve assembly alternately supplies and releases pressure for the pneumatic chambers of the artificial heart.

13. A method of actuating a plural element reciprocating pneumatic pump disposed within a toracic cavity defined by the rib cage and the diaphragm of a living, breathing body which comprises:

(a) connecting a first element of said pump by means to the rib cage,

(b) connecting a second element of said pump by means to the diaphragm, said means adapted to reciprocate said elements of the pneumatic pump upon relative movement of the rib cage and diaphragm, and

(c) reciprocating said elements of the pneumatic pump in accordance with the relative movement of the diaphragm and rib cage during inspiration and expiration of breathing of the body.

14. A method of mechanically circulating blood in the circulatory sysem of a living breathing body which comprises:

(a) operating a reciprocating pneumatic pump implanted within the thoracic cavity of the body and therein connected by means to the rib cage and diaphragm, said pneumatic pump being operated by said means which reciprocate said pneumatic pump to produce pneumatic pressure upon relative movements of the rib cage and diaphragm during inspiration and expiration of breathing of the body,

(b) supplying said pneumatic pressure to a pneumatically operated artificial heart adapted to pumping blood in the circulatory system,

(c) pumping blood within the circulatory system by means of said pneumatically operated artificial heart.

15. A pneumatically operated artificial heart comprising:

(a) a first expandable reservoir sac defining a first reservoir chamber interconnected with a first blood pump defining a first pumping chamber, a first pneumatic chamber and a first cushion chamber,

(b) a second expendable reservoir sac defining a second reservoir chamber interconnected with a second blood pump defining a second pumping chamber, a second pneumatic chamber and a second cushion chamber,

(c) each expandable reservoir sac comprising an inert flexible plastic defining a reservoir chamber provided with an inlet and an outlet, the inlet adapted to interconnection with a vein and the outlet communicating the reservoir chamber with the pumping chamber of the blood pump, said reservoir chamber adapted to maintaining a pressure upon blood contained therein at a sufiicient value so that when pumped by the pneumatic pump the blood will be maintained at a pressure greater than its vapor pressure,

(d) each of said blood pumps comprising:

(i) a pumping sac adapted to receive blood from an interconnected reservoir chamber and to deliver said blood to an interconnected artery, said pumping sac comprising an elongated inert flexible plastic sac defining the pumping chamber and provided at one end with an inlet communicating with the outlet of the interconnected expandable reservoir sac and an outlet at the opposite end communicating with an inert plastic ball check valve adapted to interconnection with an artery,

(ii) an expandable pneumatic sac located within said pumping chamber and adapted to receive and release pneumatic pressure to effect pumping of the blood contained within the pumping chamber, said pneumatic sac comprising an expandable inert plastic sac defining a pneumatic chamber provided with an inlet and an outlet, said pneumatic sac adapted to expand to fill the pumping chamber by the introduction of pneumatic pressure into the pneumatic chamber so that blood contained in the pumping chamber is expelled from the pumping chamber through the ball check valve at the pumping chamber outlet, said pneumatic sac adapted to contract from an expanded condition by the release of pneumatic pressure from the pneumatic chamber so that blood contained in the reservoir chamber is induced into the pumping chamber,

(iii) a cushion sac at least partially surrounding said pumping sac and adapted to pneumatically cushion the pumping action of the pneumatic sac, said cushion sac comprising an expandable inert plastic sac defining a cushion chamber and adapted to being compressed to thereby generate a pneumatic pressure pulse as the pneumatic sac expands to fill the pumping chamber, said pneumatic cushion sac provided with an exit to allow the release therefrom of said pneumatic pressure pulse,

(iv) a housing of inert semi-rigid plastic at least partially surrounding said cushion sac and said pumping sac, said housing adapted to confine the expansion of both the cushion sac and the pumping sac.

16. A pneumatically operated artificial heart compris- (a) an expandable reservoir sac defining a reservoir chamber interconnected with a blood pump defining a pumping chamber, a pneumatic chamber and a cushion chamber,

(b) the expandable reservoir sac comprising a flexible inert plastic sac defining a reservoir chamber provided with an inlet and an outlet, the inlet adapted to interconnection with a vein and the outlet communicating the reservoir chamber with the pumping chamber of the blood pump, said expandable reservoir sac adapted to maintaining a pressure upon blood contained therein at a sufiicient value so that when pumped by the blood pump the blood will be maintained at a pressure greater than its vapor pressure, and

(c) said blood pump comprising:

(i) a pumping sac adapted to receive blood from an interconnected reservoir chamber and to deliver said blood to an interconnected artery, said pumping sac comprising an elongated flexible inert plastic sac defining a pumping chamber provided at one end with an inlet communicating with the outlet of an expandable reservoir sac and an outlet at the opposite end communicating with an inert plastic ball check valve adapted to be interconnected with an artery,

(ii) an expandable pneumatic sac located within said pumping chamber and adapted to receive and release pneumatic pressure to effect pumping of the blood contained within the pumping chamber, said pneumatic sac comprising an expandable inert plastic sac defining a pneumatic chamber provided with an inlet and an outlet, said pneumatic sac adapted to expand to fill the pumping chamber by the introduction of pneumatic pressure into the pneumatic chamber so that blood contained in the pumping chamber is driven from the pumping chamber outlet, said pneumatic sac adapted to contract from an expanded condition by the release of pneumatic pressure from the pumping chamber so that blood contained in the reservoir chamber is induced into the pumping chamber,

(iii) a cushion sac at least partially surrounding said pumping sac and adapted to pneumatically cushion the pumping sac and adapted to pneumatically cushion the pumping action of the pneumatic sac, said cushion sac comprising an expandable inert plastic sac defining a pneumatic cushion chamber, said pneumatic cushion sac adapted to being compressed to thereby generate a pneumatic pressure pulse as the pneumatic sac expands to fill the pumping chamber, said pneumatic cushion sac provided with an exit to allow the release therefrom of said pneumatic pressure pulse,

(iv) a housing of semi-rigid plastic at least partially surrounding said cushion sac and said pumping sac, said housing adapted to confine the expansion of both the pneumatic cushion sac and the pumping sac.

17. A pneumatic pump for powering a pneumatically operated artificial heart comprising a plurality of elements, a first element of said reciprocating pneumatic pump having means for connection to the rib cage of the body and a second element having means for connection to the diaphragm of the body, said means operable to reciprocate said pump elements upon relative movement of the rib cage and diaphragm during inspiration and explration of breathing of the body, said pneumatic pump adapted to supply pneumatic pressure to a pneumatically operated artificial heart upon inspiration of the body at a rate dependent upon the frequency and force of relative movements of the rib cage and diaphragm during inspiration of breathing.

18. A means for powering a pneumatically operated artificial heart comprising:

(a) a control means comprised of a plurality of pneumatic pressure accumulators for supplying pneumatic pressure to and receiving pneumatic pressure released from a pneumatically operated artificial heart and a control valve assembly interconnected with said pneumatic pressure accumulators and adapted to interconnection with an artificial heart for controlling the supply and release of pneumatic pressure for the artificial heart to thereby operate said artificial heart, a first and a second of said accumulators being positioned between a reciprocating pneumatic pump means and the control valve assembly, said first accumulator interconnected with a reciprocating pneumatic pump means and the control valve assembly and thereby adapted to be charged with pneumatic pressure produced by the pneumatic pump means and to supply pneumatic pressure to the pneumatic control valve assembly, said second accumulator interconnected with the control valve assembly and the reciprocating pneumatic pump means and thereby adapted to be charged with pneumatic pressure released from the control valve assembly and to supply pneumatic pressure to the pneumatic reciprocating pump, said pneumatic control valve assembly comprising a plurality of valve means operable in unison at a rate proportional to the value of the pneumatic pressure supplied by said first accumulator, said valve means operating to alternately supply and release pneumatic pressure for a pneumatically operated artificial heart and thereby operate said artificial heart, and

(b) a reciprocating pneumatic pump means comprised of a plurality of elements, a first element of said reciprocating pneumatic pump having means for connection to the rib cage of the body and a second element having means for connection to the diaphragm of the body, said means adapted to reciprocate said pump elements upon relative movement of the rib cage and diaphragm during inspection and expiration of breathing of the body, said pneumatic pump supplying pneumatic pressure to said first pressure accumulator upon inspiration of the body at a value dependent upon the frequency and force of relative movements of the rib cage and diaphragm during inspection of breathing,

whereby variable pumping rate of an interconnected pneumatically operated artificial heart is attained according to the requirement of the body by maintaining a proportion between the rate of the body breathing, the value of pneumatic pressure supplied to the first pressure accumulator, and the rate at which the control valve assembly alternately supplies and releases pressure for the pneumatic chambers of the artificial heart.

19. In the artificial heart system described in claim 1 a control means for operating a pneumatically operated artificial heart by the alternate supply and release of pneumatic pressure provided to the control means by a pneumatic pressure source comprising a plurality of pneumatic pressure accumulators for supplying pneumatic pressure to and receiving pneumatic pressure released from a pneumatically operated artificial heart and a control valve assembly interconnected with said pneumatic pressure accumulators and adapted to interconnection with an artificial heart for controlling the supply and release of pneumatic pressure to and from the pneumatic pressure accumulators for the artificial heart, a first of said accumulators adapted to be charged by the pneumatic pressure source and to supply pneumatic pressure to the pneumatic control valve assembly, said pneumatic control valve assembly comprising a plurality of valve means operable in unison at a rate proportional to the valve of the pneumatic pressure supplied by said first accumulator, said pneumatic control valve assembly operating an interconnected artificial heart by the alternate supply and release of pneumatic pressure for the artificial heart.

20. In the artificial heart system described in claim 1 a pneumatic control valve assembly for operating a pneumatically operated artificial heart with pneumatic pressure supplied from a pneumatic pressure source comprising a plurality of valve means operable in unison to receive pneumatic pressure from a pneumatic pressure source and to alternately supply and release said pneumatic pressure to a pneumatically operated artificial heart to thereby operate said artificial heart, said valve means operating to supply and release pneumatic pressure at a rate proportional to the value of the pneumatic pressure supplied by the pneumatic pressure source.

References Cited UNITED STATES PATENTS 3,182,335 5/1965 Bolie 31 3,208,448 9/1965 Woodward l281 3,327,322 6/1967 Norton 3l 3,449,767 6/1969 Bolie 31 OTHER REFERENCES Artificial Intracorporeal Heart, by F. W. Hastings et al., Trans. Amer. Soc. Artif. Int. Organs, vol. VII, 1961, pp. 323425.

The'Artificial Heart-Exemplar of Medical-Engineering Enterprise, by N. Lindgren, I.E.E.E. Spectrum, September 1965, vol. 2, No.9, pp. 67-83.

A Small Ventrical-Type Pump For Prolonged Perfusions: Constructions And Initial Studies, Including Attempts To Power A Pump Biologically With Skeletal Muscle by B. K. Kusserow et al., Trans. Amer. Soc. Artif. Int. Organs, vol. X, 1964, pp. 7478.

RICHARD A. GAUDET, Primary Examiner R. L. FRINKS, Assistant Examiner US. Cl. X.R.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3182335 *Feb 27, 1963May 11, 1965Univ Iowa State Res Found IncDual-chamber artificial heart
US3208448 *Feb 2, 1962Sep 28, 1965Kenneth E WoodwardArtificial heart pump circulation system
US3327322 *Jul 27, 1964Jun 27, 1967Trw IncArtificial heart powered by a fluid pressure pump means simulating the action of the human heart
US3449767 *Sep 24, 1965Jun 17, 1969North American RockwellArtificial heart regulating system
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3641591 *Feb 6, 1970Feb 15, 1972Univ UtahSoft shell mushroom shaped heart
US3682107 *Dec 29, 1969Aug 8, 1972Macmanus JohnApparatus for dispensing material on pastry and the like
US3720485 *Jul 1, 1971Mar 13, 1973Holman NArtificial heart
US3731322 *Jan 8, 1971May 8, 1973Siemens AgImplantable artificial heart with externally worn fluid pressure energy transmitter
US3827426 *Jul 16, 1971Aug 6, 1974Page MProsthetic pump
US4078267 *Dec 21, 1976Mar 14, 1978Akademia MedycznaArtificial heart propelled by respiratory muscles
US4222127 *Jun 2, 1978Sep 16, 1980Donachy And PierceBlood pump and method of pumping blood
US4369530 *May 19, 1981Jan 25, 1983Foxcroft AssociatesHydraulically actuated cardiac prosthesis and method of actuation
US4376312 *May 19, 1981Mar 15, 1983Foxcroft AssociatesHydraulically actuated cardiac prosthesis
US4381567 *Sep 15, 1981May 3, 1983Foxcroft AssociatesHydraulically actuated total cardiac prosthesis with reversible pump and three-way ventricular valving
US4389737 *Sep 15, 1981Jun 28, 1983Foxcroft AssociatesHydraulically actuated cardiac prosthesis with three-way ventricular valving
US4397049 *Sep 15, 1981Aug 9, 1983Foxcroft AssociatesHydraulically actuated cardiac prosthesis with three-way ventricular valving
US4473423 *Sep 16, 1983Sep 25, 1984University Of UtahUsing thermoplastic elastomer material
US4704120 *Jun 25, 1986Nov 3, 1987Biomasys SarlHeterotopic artificial heart consisting of a one-piece cardiac prosthesis for biventricular assistance and implantable in the right hemithorax
US4838889 *Jul 23, 1986Jun 13, 1989University Of Utah Research FoundationVentricular assist device and method of manufacture
US4938766 *Aug 28, 1987Jul 3, 1990Jarvik Robert KProsthetic compliance devices
US4994078 *Feb 16, 1989Feb 19, 1991Jarvik Robert KIntraventricular artificial hearts and methods of their surgical implantation and use
US5092879 *Mar 5, 1990Mar 3, 1992Jarvik Robert KIntraventricular artificial hearts and methods of their surgical implantation and use
US5344385 *Sep 30, 1991Sep 6, 1994Thoratec Laboratories CorporationStep-down skeletal muscle energy conversion system
US5443504 *Jun 28, 1994Aug 22, 1995Hill; John D.Basic skeletal muscle energy conversion system
US5653676 *Jun 7, 1995Aug 5, 1997Thoratec Laboratories CorporationStep-down skeletal muscle energy conversion method
US5701919 *Jun 7, 1995Dec 30, 1997Thoratec Laboratories CorporationStep-down skeletal muscle energy conversion system
US5984857 *Aug 29, 1994Nov 16, 1999Thoratec Laboratories CorporationStep-down skeletal muscle energy conversion system
US6981613 *Dec 6, 2002Jan 3, 2006Cullen KamisugiPortable pressurized liquid storage system
US7121291 *Oct 14, 2003Oct 17, 2006Hiroshima UniversityCheck valve, auxiliary circulating device and method for driving the auxiliary circulating device
Classifications
U.S. Classification623/3.22, 623/3.28, 417/394, 137/106
International ClassificationA61M1/12, A61M1/10
Cooperative ClassificationA61M2001/1003, A61M1/127, A61M1/106
European ClassificationA61M1/12F