US 3579644 A
Description (OCR text may contain errors)
y 5, 1971 w. a. ESMOND v ARTIFICIAL HEART Filed Feb. 26. 1969 2 Sheets-Sheet 1 SKEW- n @555 a UJILUAM G. ESMOND' ATTORNEY May 25, 1971 w. G. ESMOND mnmcmn HEART Filed Feb. 26', 1969 2 Sheets-Sheet 2 UHLLIAM G.ESMOND BY M4 ATTORNEY United States Patent 3,579,644 ARTIFICIAL HEART William G. Esmond, 537 Stamford Road, Baltimore, Md. 21229 Filed Feb. 26, 1969, Ser. No. 802,580 Int. Cl. A61f 1/00 US. Cl. 3--1 8 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to an artificial heart which is so constructed whereby it may be mounted in the human body and permanently connected to the blood vessels of that body with the heart being powered by an external source. The heart makes use of a low boiling point liquid and a heating coil which is periodically actuated so as to effect boiling of the liquid, followed by the rapid cooling of the liquid to condense the same whereby an expansion and contraction function is performed and constantly repeated so as to effect a pumping action.
This invention relates in general to new and useful improvements in pumps, and more specifically to an artificial heart which is specifically constructed for mounting within the human chest.
In accordance with this invention, there is provided a novel heart which includes two pump sections, in the same manner as the human heart, and which heart is mechanically actuated to actuate the two pump sections thereof in the same manner and the same speed as the human heart so as to effect an efiicient circulation of blood through the human body.
A primary feature of this invention is to provide a pump section for a human heart which includes a fixed capacity housing having disposed therein a compartment with one of the walls of the compartment being in the form of a diaphragm which may be repeatedly extended and distended so as to vary the volume of the housing and thus effect a pumping action into and out of the housing. Mechanical means are positioned within the compartment for effecting the extending and distending of the diaphragm with the mechanical means being operable by a power source disposed externally of the body.
Another feature of this invention is to provide an artificial heart wherein the motor power for the heart is in the form of a compartment having a diaphragm forming one wall thereof, the compartment being filled with a low boiling point liquid, and there being associated with the compartment both an electrical heating element and a heat exchanger to repeatedly boil and condense the liquid Within the compartment.
A further object of this invention is to provide an artificial human heart which may be readily mounted within the chest cavity in lieu of the usual heart and connected to the blood vessels of the human, the heart including a simple housing divided into two pump units by means of a centrally located heat exchanger, and each of the pump units including a compartment of which the heat exchanger forms a wall and wherein each compartment has a wall thereof in the form of a diaphragm which is artificially extended and distended by repeatedly boiling and condensing a low boiling point liquid disposed within the compartment, the liquid being heated by means of an electrical heating unit, and the liquid being cooled by blood of the body being circulated through the heat exchanger.
With the above and other objects in view that will hereinafter apear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:
In the drawings:
FIG. 1 is a schematic view of the upper portion of a human body showing mounted therein the artificial heart which is the subject of this invention.
FIG. 2 is an enlarged elevational view of the artificial heart of FIG. 1 with portions thereof broken away and shown in section in order to show generally the details thereof.
FIG. 3 .is a transverse vertical sectional view taken along the line 3-3 of FIG. 2 and shows specifically the details of the two pump units of the heart.
FIG. 4 is a sectional view taken along the line 44 of FIG. 3 and shows specifically the details of the internal construction of a pump unit, including the valving thereof.
FIG. 5 is a transverse sectional view taken along the line 5-5 of FIG. 3 and shows further the specific details of the two pump units.
Referring now to FIGS. 2 through 5 in particular, it will be seen that there is illustrated the specific details of the artificial heart which is the subject of this invention, the artificial heart being generally identified by the numeral 10. The artificial heart 10 basically includes a housing which is generally identified by the numeral 11. The housing 11 is formed of a pair of shells 12 and 13 which are suitably secured to opposite sides of a centrally located heat exchanger 14. The shells 12 and 13 are preferably molded or vacuum formed plastic shells, but may be formed of metal coated with a suitable coating material such as silicone, tetrafiuroethylene, etc.
The shell 12 defines a pump unit which is generally identified by the numeral 15, while the shell 13 defines a pump unit, which is generally defined by the numeral 16. Basically, the two pump units 15 and 16 are identical except for being right and left hand.
The two pump units 15 and 16 being substantially identical, the specific details of the pump unit 15 will be described here. The pump unit 15 includes a compartment, which is generally defined by the numeral 17, which is mounted within the shell 12 with the heat exchanger 14 forming one wall thereof. With particular reference to FIG. 5, it will be seen that the heat exchanger 14 includes a pair of vertically extending plates 18 which are arranged in spaced parallel relation and which have the central portion thereof connected together by a pleated plate 20. The plate 20 forms both a separator for the plates 18 and a How control divider. The plates 18 are also connected together by end plates 21 so as to be of a sealed construction. The upper ends of the plates 18 and 21 are configurated so as to define an inlet 22 while the lower ends thereof are configurated so as to define an outlet 23. The end plates 21 have extending thereabout suitable spacers 24 which are clearly shown in FIGS. 4 and 5.
Referring once again to the construction of the com partment 17, it will be seen that one of the plates 18 of the heat exchanger 14 forms a wall of the compartment 17. The opposite wall of the compartment 17 is formed by a flexible diaphragm 25.
There is also mounted within the compartment 17 a bafile 26 which limits the collapsing of the diaphragm 25 for a specific purpose to be set forth hereinafter. It is to be noted that peripheral portions of the diaphragm 25 and the baffle 26 are clamped between a flange 27 of the shell 12 and the spacers 24 of the heat exchanger 14. Suitable fasteners 28 secure together the components of the artificial heart 10.
It will be readily apparent from FIGS. 3 and 5 that the shell 12 defines a specific volume chamber 30. However, the chamber 30 having the compartment 17 positioned therein, has a variable effective volume which changes as the diaphragm 25 is extended or distended. Thus, by reice peatedly extending and distending the diaphragm 25, a pumping action may be effected. To this end, the pump unit is provided with an inlet fitting 31 and an outlet fitting 32. The inlet fitting 31 has a one way valve 33 associated therewith which permits the entrance only of blood. In a like manner, the outlet fitting 32 has asso ciated therewith a one-way valve 34 which permits only the discharge of blood. Thus, as the volume of the chamber 30 isdecreased, blood is forced out through the outlet fitting 32 and then, when the volume of the chamber 30 is increased, blood is drawn into the chamber 30 through the inlet fitting 31.
In order that the diaphragm will be automatically extended and then distended, there is disposed within the compartment 17 a low boiling point liquid 35 such as methyl alcohol or suitable low boiling point (just above body temperature) liquids including Freon, etc. There is also mounted within the compartment 17 an electrical heater 36. At this time it is pointed out that the bafiie 26 prevents the diaphragm 25, when distended, from contacting the heater 36 so as to prevent accidental rupture thereof.
When the heater 36, which is mounted on the associated wall 18 of the heat exchanger 14, is energized, it will rapidly heat the liquid 35 to effect boiling thereof. This will result in expansion of the liquid so as to extend the diaphragm 25 and thus reduce the effective volume of the chamber 30. In timed relation, the heater 36 is energized and then de-energized. After the heater 36 is deenergized, blood flowing through the heat exchanger 14 in the manner to be described hereinafter, will rapidly cool the boiling liquid 35 so as to condense the vapor thereof and thereby reduce the volume of the liquid 35 with the resultant distending of the diaphragm 25 so as to increase the volume of the chamber and draw fresh blood thereinto.
At this time it is pointed out that although the internal construction of the pump unit 16 is identical to that of the pump unit 15 and like internal components thereof will be identified by like numerals, the inlet fitting of the pump unit 16 will be identified by the numeral 37 while the outlet fitting thereof will be identified by the numeral 38, as is best shown in FIG. 4.
At this time it is particularly pointed out that all of the components of the artificial heart 10 must be formed of suitable material which is compatible with the human body, including the blood thereof. It will be readily apparent that different materials may be utilized for the forming of the different parts of the artificial heart. Accordingly, no specific materials are set forth here. On the other hand, it is particularly pointed out that the compartments 17 must be effectively sealed from the chambers 30 in order to prevent the liquid disposed therein from mixing with the human blood.
In order that the artificial heart 10 may be most acceptable to the human body, it is preferred that the entire artificial heart 10 be encapsulated in a suitable foam material 40 so as to have a soft round contour. A silicone foam has been found to be an acceptable material.
In order that the artificial heart 10 may be readily connected to the human body blood vessels, it is preferred that the inlet and outlet fittings thereof be formed of a suitable material which may be sewn directly to the blood vessels. Suitable knitted plastics have ben found to be acceptable. Thus, the inlet and outlet fittings may be formed of these knitted plastic materials, or suitable adapter materials may be connected thereto.
Referring now to FIG. 1 in particular, it will be seen that there is illustrated a human body 41 having positioned therein and coupled thereto an artificial heart 10 formed in accordance with this invention. It is to be noted that the inlet fitting 31 is connected to the superior vena cava 42 and the inferior vena cava 43 in the customary manner, while the outlet fitting 32 is connected to the puhnonaiy artery 44. The pump unit 16 has the inlet 4 fitting 37 thereof connected to the pulmonary veins 45 while the outlet fitting 38 is connected to the aorta 46.
In order that the heat exchanger 14 may function, the arch of aorta 47 is coupled to the inlet 22 of the heat exchanger 14 while the outlet fitting 23 of the heat exchanger is connected to the abdominal aorta 48. The circulating blood of the body 41 will be at a sufficiently lower temperature than the heated liquid of the pump units to effect a rapid cooling and condensing thereof.
It is to be understood that the exact position of the artificial heart 10 within the body is immaterial. The artificial heart, when positioned within the body, will be rotated so as to be most receptive to the body.
Referring once again to FIG. 1, it will be seen that the electrical heating units 36 have wires 50 and 51 coupled thereto and to suitable coils 52 and 53, respectively, with the wires and coils being embedded within the human body with the coils -52 and 53 being disposed closely adjacent an external surface or skin of the body or the silicone rubber coated wires may directly penetrate the skin to the exterior. The coils 52 and 53 are secondary coils of an induction transformer 54 which includes one or more primary coils 55 depending whether or not it is desired that the pump units 15 and 16 be actuated simultaneously or in sequence. The primary coil 55 has leads 56 and 57 connected to a suitable power source 58. The power source 58 may be of any desired type and of itself is not a part of this invention. It is to be understood, however, that the power source 58 must pulse current through the primary coil or coils 55 at a regulated rate. It is also preferable that the power source 58 be provided with suitable control means 66 for regulating the level of the power input into the heating units 36. Also, it must be provided with a suitable control unit 61 for regulating the rate of power pulsing so that the pumping or beating of the artificial heart 10 may be regulated. The power unit 58 is preferably one which may be battery operated, so as to be portable, although it is preferred that it also be provided with suitable connections to utilize house, automotive, etc. current, so as to reduce the load on the power supply batteries.
If desired, means may be provided for recharging the low boiling point liquid in each compartment 17. As is shown in FIG. 1, a silicon rubber bulb 70 for each compartment 17 may be implanted just below the shin and connected to the respective compartment by a line 71. The fluid 35 then may be conveniently checked, replenished or replaced by means of a needle passed through the shin and into the bulbs 70.
Although only a preferred embodiment of the artificial heart has been specifically illustrated and described herein, it is to be understood that minor variations may be made therein without departing from the spirit of the invention.
1. An artificial heart comprising a sealed housing, inlet and outlet tubes connected to said housing for the circulation of blood into and out of said housing, and a pump unit within said housing for effecting the fiow of blood into and out of said housing, said pump unit including a sealed compartment within said housing, said compartment having a wall thereof in the form of a diaphragm, and operating means within said compartment for repeatedly extending and distending said diaphragm to repeatedly change the volume of said housing, said operating means including a low boiling point liquid filling said compartment in the distended position of said diaphragm, and heater means for periodically heating said liquid and cooling means for periodically cooling said liquid to produce a bubble capable of extending and distending said diaphragm.
2. The artificial heart of claim 1 wherein said heater means includes an electrical heater, wires connected to said electrical heater and extending externally of said compartment and said housing, and power means coupled to said wires for pulsing current to said electrical heater.
3. The artificial heart of claim 2 wherein said power means includes a transformer coil particularly adapted to be internally positioned within a living body, a second transformer coil adapted to be mounted externally of a living body in operative position relative to said first coil, and power supply means connected to said second coil.
4. The artificial heart of claim 1 wherein at least one Wall of said compartment is a part of a heat exchange device for cooling the heated liquid to effect the condensing of the heat formed bubble and the resultant distending of said diaphragm.
5. The artificial heart of claim 4 together with means for circulating body blood as the cooling media for said heat exchange device.
6. The artificial heart of claim 4 wherein said heater means are mounted on said heat exchange device.
7. The artificial heart of claim 4 wherein said housing is divided in half by said heat exchange device to form two separate pump assemblies, and wherein there are two pump units with said heat exchange device forming a common wall of the compartments of said pump units.
8. The artificial heart of claim 1 wherein said housing is encased within a soft foam material for direct mounting within a living body in place of the heart of such living body.
References Cited UNITED STATES PATENTS 3,039,399 6/1962 Everett l03150 3,048,165 8/1962 Norton 1281 3,434,162 3/1969 Wolff 31 RICHARD A. GAUDET, Primary Examiner G. F. DUNNE, Assistant Examiner US. Cl. X.R. 417-394