US2832294A - Heart pump - Google Patents

Description

April 1958 E. v. RIPPINGILLE 2,832,294

HEART PUMP Filed Feb. 18, 1954 7 Sheets-Sheet 1 I (.l l 1 i X9, INVENTOR f/QM ATTORNEY April 29 1958 E. v. RIPPINGILLE HEART PUMP 7 Sheets-Sheet 2 Filed Feb. 18, 1954 WW W W w W A April 29, 1958 E. v. RIPPINGILLE 9 HEART PUMP Filed Feb. 18, 1954 7 Sheets-Sheet s INVENTOR ATTORNEY 29, 1958 E. v. RIPPINGILLE HEART PUMP 7 Sheets-Sheet 5 Filed Feb. 18, 1954 April 29, 1958 E. v. RIPPINGILLE 298329294 HEART PUMP Filed Feb. 18, 1954 7 Sheets-Sheet 6 INVENTOR ATTORNEY April 29, 5 E. v. RIPPINGILLE 2,832,294

HEART PUMP 2/1 ZJV Q, 1/ W Filed Feb. 18, 1954 7 Sheets-Sheet '7 BNVENTOFZ a/afa United States are HEART PUMP Edward V. Rippingille, Farmington, Mich, assignor to beneral Motors Corporation, Detroit, Marla, a corporation of Delaware Application February 18, 195 i, Serial No. 411,061 5 Claims. (Cl. 103 at This invention relates to fluid pumps generally and more particularly to a mechanical heart pump capable of simulating the action of the human heart in moving human blood without injury or damage to the delicate cellular structure thereof.

Many of the failures in the past to develop a successful heart pump by means of which human blood could be bypassed around the living heart to allow remedial surgery thereto is believed to some degree to be attributable to the previous inability of providing a satisfactory valve system for such a pumping unit. A satisfactory check valve system was first proposed in copending application S. N. 370,731 Mechanical Heart Pump or the Like, filed July 28, 1953 in the name of this same inventor. The necessity for careful treatment of the delicate cellular composition known as blood to prevent injury or damage to the individual blood cells was therein set forth in some detail. This invention is an improvement over the previous heart pump which makes use of a dilferent type of check valve and pump structure having even greater adaptability for passing human blood or other cellular fluids. The proposed check valve and pump structure is similar to, but a great improvement over, the structure disclosed in copending application S. N. 401,161, Fluid Pump filed December 30, 1953 also in the name of this same inventor.

The improved fluid pump disclosed herein includes many novel and advantageous features. A flexible walled tubular member with a through flow fluid passage is provided for passing human blood or other cellular fluid and has tricuspid check valves of yieldable and readily deformable material disposed at opposite ends of such passage. The check valves are capable of providing a maximum opening without stretching or deforming the valve and with a minimal obstruction to fluid flow. The valves are readily closed with a negligible unit pressure between closing surfaces with respect to the pressure likely to injure or damage the individual cells of the moving fluid. External pressure is applied to the flexible walled tubular member for opening and closing opposite check valves. Where positive and negative air pressures are alternately employed for flexing the flexible walled flow passage member, means are provided to vent the pressures to atmosphere prior to the application of the opposite pressure sources. A filter or surge chamber is also provided which is adapted to remove air bubbles, prevent excess surge pressures, filter the blood, and act as a flow gauge.

The proposed invention as adapted for use in moving human blood and for. simulating the pumping action of the human heart is a relatively small, compact, lightweight and mobile unit. The proposed pump may be moved about by one person with no difliculty. No longer must the patient be moved to the machine; the machine may be brought to the patient. The need of such a compact unit in war zones and disaster areas makes its mobile characteristics alone invaluable. The proposed heart pump is also simple in operation and is constructed of transparent materials to allow ready inspection. A minimum of instruction is required to qualify a person to operate the pump. The pump includes a minimum number of parts easily assembled and disassembled for inspection, repair or other purposes. The parts with which human blood is adapted to come in contact is reduced to a minimum; greatly simplifying problems of sterilization. Even further, disposable elements are employed which may be kept in sterile wrappings until needed and then may be readily adapted for use within the proposed pump.

While the heart pump herein described in and of itself is a greatly simplified improvement over previous heart pumps the principals and basic structure are adaptable for F even more fundamental use in extreme emergencies. Op-

erational pressures may be supplied by compressed and evacuated air cylinders. Any available power supply source may be adapted to operate the pump. This includes not only hand operation of the pump itself but even further the manipulation of the heart sac and valve assembly by the periodic and methodical contraction of ones hand about the heart sac alone.

In the drawings:

Figure 1 is a side view of a heart pump embodying the principles of this invention and hereinafter described.

Figure 2 is a front view of the proposed heart pump.

Figure 3 is an enlarged view of the upper portion of the heart pump shown in Figures 1 and 2 partly broken away and shown in cross section.

Figure 4 is an enlarged view of the lower portion of the heart pump shown in Figures 1 and 2 partially broken away and shown in cross section.

Figure 5 is a cross sectional view taken in the plane of line 5-5 of Figure 7 looking in the direction of the arrows thereon.

Figure 6 is a cross sectional view taken in the plane of line 66 of Figure 7 looking in the direction of the arrows thereon.

Figure 7 is a top view of the proposed heart pump.

Figure 8 is a cross sectional view taken in the plane of line 3-% of Figure 2 looking in the direction of the arrows thereon.

Figure 9 is an enlarged detailed view of one of the air valves taken in the plane of line 9-9 of Figure 7 and viewed in the direction of the arrows thereon.

Figure 10 is a detailed cross sectional view of the heart sac and valve assembly used in the proposed heart pump.

Figure 11 is a detailed View of the fluid check valve used in the proposed heart pump.

The mechanical heart pump shown in the drawings includes a cam housing 10, base member 12, passage member 14, and filter housing 16. The base member 12 is adapted to be secured to a table or other supporting member 18 as by screws 20. The cam housing 10 projects below the supporting member 18 and is secured to the base member 12 by machine screws 19. A camshaft 22 extends through opposite side walls 24 and 26 of the cam housing It) and is jo-urnalled within ball bearings 28 and 3d. The one bearing 28 is retained within a bearing support 32 by lock ring 34. The bearing support 32 is secured to the side wall 24 of the housing ll) as by screws 36. A locknut 38 and a lock washer 40 are secured to one end of the camshaft 22 with a cover plate 42 secured thereover by screws 44. A pulley 46 is secured to the other end of the camshaft 22 as by the head screw 43 holding the pulley against the shoulder 50 formed on the camshaft. There are three earns 52, 54, and 56 secured to the camshaft 22. The one cam 52 is essentially circular having only small raised portions 58 formed on diametrically opposite sides of its circular surface. The other two cams 54 and 56 each have semicircular asaaaea surfaces 60 and 62 of difierent radii joined together as at 64. The cams 54 and 56 are secured to the camshaft with their raised surfaces 62 arranged approximately 180 apart.

Besidesthe camshaft 22 which is extended through the cam housing 10, there are rocker arm shafts 66 e1rtended through the housing below and on each side of the camshaft. The rocker arm shafts 66 are journalled at opposite ends within portions 68 and 71) of the housing 10. One end of each rocker arm shaft 66 is secured against axial movement by a set screw 72. A socket head plug 74 is threaded into each shaft access '76. Rotatably mounted upon each rocker arm shaft 66 is a rocker arm 78 having arms St) and 82 extending outwardly on opposite sides thereof. The arms 81 are formed as yo-kes to receive rollers 84 adapted to engage cams '4 and The outer ends of the arms 82 are formed with seats 36 engaging push rods 88. The push rods $53 are slidably journalled within portions 91) formed from the housing 10. The rods are hollow with inserts 92 and 5 4 in opposite ends for lightening the weight of the rods and providing more durable end pieces. An extension rod is received within the one insert an and extends through the base member 12 and into the passage member 14. An air chamber 98 is formed within the passage member 14- near the upper end of the extension rod 96 and a valve head 100 with an annular air seal ring 1112 is secured to the end of the rod for closing off the chamber. Spring collar 104 is secured to one end of the extension rod and another spring collar 1116 is secured to the bearing sleeve 108 for retaining a coil spring 1111 tending to close the valve 100. A second coil spring 112 is disposed about the other end of the extension rod 96 between the neck 114 of the bearing sleeve 108, extending into the air chamber 98, and the valve head 1%. This spring 112 tends to assist the valve 100 in opening.

Although the air chamber 98 may be formed directly within the passage member 14, in the present instance a hollow cylindrical insert 116 is provided with a set screw 118 threaded through the side of the housing to hold it in place. Air flow passages 121i, 122, 124 and 126 are formed through the passage member 14 and base member 12 and communicate with the air chamber 913. Socket head plugs 128 and 131) are threaded into the ends of passages 120 and 124 to close ofi the passages from the atmosphere and to provide access when required. Passage 126 is adapted to receive suitable tubing 132 to be connected to an air pressure or vacuum supply source.

The passage member 14 is made of transparent material in the present embodiment to enable visual inspection of valve operation and fluid flow. Such inspection enables immediate repair at the exact point of malfunction; so important in surgical operations where every second saved is of major importance. The passage member 14 seats upon the base member 12 and the filter housing 16 is re-- ceived upon the upper end of the passage member. The filter housing 16 and passage member 14 are secured to the base member 12 by tie rods 134. One end of the tie rods 134 is threaded into the base member 12 and is locked as by set screw 136. The other end of the tie rods extends through the base portion 138 of the filter housing and is threaded to receive a wing nut 1411. The tie rods 134 are recessed within grooves 142 formed in the sides of the passage member and thereby also act as guides to center the passage member 14 properly over the base member 12.

The central portion 144 of the passage member is formed to provide an enlarged cylindrical chamber 6 adapted to receive the heart sac and valve assembly 1 Passages 151) and 152 are formed through opposite sides of the passage member 14 in communication with the chamber 146. These passages are disposed directly over the air'chambers 95 and are adapted to receive the valve heads The ends of passages 1511 and 152 are closed off by. access plates 154 secured thereover as by screws iii) 156. Access is also provided to passages 151) and 152 by socket head plugs 158 threaded within the passage member in axial alignment with air chambers 98. Suitable gaskets 161 are provided about all accesses to the air chamber or associated passages as around the acess plate plugs 15%, 123, 131 etc.

Aside from the major air valves 1% provided within the passage member there are also air vent or bleed-off valves 162. The valves 162 are operated by the cam 52 mounted in the cam housing 10. The opposite sides of the homing are formed to provide a ledge 164 upon which is received a cross bar 166. The cross bar is secured to a push rod 163 slidably journalled for pure axial movement within the housing 10. The cross bar 166 extends across the cam housing 10 at a distance above the camshaft equal to the radius of the cam 52 and such that the cam surface 58 thereof is adapted to lift the bar. As the bar 166 is lifted the push rods 168 are also lifted. The push rods 168 engage an extension rod 170 slidably journalled within a sleeve bearing 172 and a passage 174 formed in the passage member 14. A spring collar 176 secured to the end of the extension rod and a collar 17% formed from the sleeve bearing 172 retain a coil spring 1811 therebetween tending to urge the extension rod 174) in constant engagement with the push rod 168. A valve head 182 is formed at the end of each extension rod 174; within a chamber 184 communicating with the air chamber 146 through passage 150 or 152. The valve head 182 seats upon a gasket 186 for air tight closure. Access to the chamber 134 is provided by socket head plug 188 threaded within the passage member wall over the valve head 132. The shank of the extension rod 17-29 just below the valve head 182 is elevated on three sides as at 192 to allow for the flow of air to or from the chamber 184 through passage 174 when the valve head is lifted. The passage 174 communicates with passages 194 and 196 venting the air chamber 146 to the atmospheric pressure within the cam housing 16.

Inasmuch as the cam housing 10 is closed off from the atmosphere for dust protection as by plate 198 secured to the bottom of the housing by screws 2%, a breather tube or pipe 202 is provided Within the cam housing 10. The breather tube 2112 opens near the top of the cam housing 10 and is threaded at its open end for receiving a muffler or air silencer if desired.

The heart sac and valve assembly 148 adapted to be disposed within the enlarged air chamber 146 is positioned between the base member 12 and the filter housing 16. The assembly includes transparent cylindrical sleeve 2514 having a plurality of holes 206 formed therethrough. An annular gasket 268 is disposed at each end of the cylinder 204 and a collar member 210 is received over each end of the cylinder. A fitting 212 is received centrally through each collar 210 and is positioned by a flange 214 formed about the fitting. For greater ease in assembling the fitting 212 within the collar 210 the collar is split in two pieces and is held together by a lock ring 216. The opposite ends of each fitting 212 are rolled over as at 218 and 221i and are adapted to receive the ends of the tricuspid check valve 222. Although the ends of the valve 222 may be formed to cooperate with the rolled edges 213 and 220, in the present instance ties 224, such as rubber bands or the like, assist in holding the valve to the fitting 212.

The valve 222 is essentially a flexible lipped closure operable by a difierential in pressure on opposite sides thereof with closing flaps or cusps 226 of yieldable material incapable of exerting excessive unit pressures in closing. By providing a circular valve with three cusps the extended surface or flap 228 may collapse on the secured surface 231? without stretching the cusps so long as the dimension of the extended surface is equal to or greater than /avrD, the circumference of the opening. The pressures required to open and close the valve 222 are depend ent upon the flexibility of the individual cusps 226 and may be varied to suit any desired or necessary conditions.

The ease of opening and closing the valve, the uniflow characteristic, the minimal unit pressures is closing, and the lack of elastic stress enabling a longer serviceable valve highly adaptable for use in passing a cellular fluid such as blood without injury or damage thereto.

The fitting 212 is provided with a grooved retainer ring 232 for receiving the ends of a flexible walled tubular sac 234 thereover. The sac forms a fluid flow passage 235 separated from the chamber 146. The sac is held on the ring 232 by a tie 236. The sac 234 is of a molded, flexible, and readily deformable material such as rubber and when collapsed is adapted to take the general cross-sectional shape of a four point star. When the sac 234 is expanded it is circular in cross-section and approaches the side walls of the sleeve 204.

A sealing ring 238 is positioned about each fitting 212 adjacent the flange 214. The heart sac and valve assembly 148 is seated upon one sealing ring 238 within the seat 240 formed in the base member 12. The base portion 138 of the filter housing 16 is received on the other sealing ring 238 and the assembly is secured within the air chamher 146 of the passage member 12 by tightening the wing nuts 140.

The base member 12 includes a removable insert 242 which actually has the seat 240 formed therein. The insert 242 is formed to provide a cup-shaped central portion 244 covering the end of the fitting 212 and receiving the rolled edge 220 about an aperture 246 for sealing the fitting over the aperture. A conduit 248 is secured within the aperture 246 and is formed to extend through an opening 250 provided in the side of the base member 12. The end of the conduit 248 is threaded and is adapted to receive a connector nipple 252 with a coupling member 254 provided therebetween. A seal 256 is placed between the engaging ends of the conduits.

Gaskets 258 and 260 are disposed on opposite ends of the passage member 14 between the base member 12 and the filter housing 16 to insure an air tight seal for the air chamber 146. The base portion 138 of the filter housing 16 is received upon the upper end of the passage member 14 and has a tubular section 262 disposed centrally over the heart sac and valve assembly 148. A seat 264 is formed within the base portion 138 to receive the sealing ring 238 and the fitting 212 is extended within the neck 266 of the tubular section 262. An annular disk 268 is secured across the tubular section 262 and is adapted to seat upon the rolled edge 220 of the fitting 212 for sealing the fitting over the aperture 270 formed in the disk. A

flow conduit 272 is secured to the disk 268 and is extended through the tubular section 262 in concentric alignment therewith. Secured to the end of the conduit 272 is the fitter holder 274 which includes two externally grooved retainer rings 276 held in spaced relation by braces 278. A porous filter sock 280 is disposed about the braces 278 and is tied at each end as at 282 and 284 to the retainer rings 276.

A conduit 286 having a flow passage 288 is secured to the tubular section 262 of the filter housing 16. The passage 288 communicates with the annular chamber 290 formed between the conduit 272 and inner wall of the tubular section. The conduit 286 is threaded at its outer end and is adapted to receive a connector nipple 292 provided with a coupling 294 and seal 296. The upper end of the tubular section 262 is flanged or cupped as at 298 to receive the sealing ring 300 and the transparent cylindrical sleeve 302. Another sealing ring 304 is disposed upon the other end of the sleeve 302 and a cover 306 is received thereover for closing the upper end of the sleeve. Tie rods 308 and wing units 310 are adapted to hold the cover 306 and sleeve 302 in fluid tight engagement upon the base portion 138 thereby forming a surge chamber 316 within the sleeve 362 which is in communication with the fluid flow passage 235. A fitting 312 is centrally secured to the cover 306 and is provided with a passage 314 553 communicating with the surge chamber 316 of the sleeve 302. A closure plug 318 is threaded within the passage 314 and is adapted to close or open the air bleed passage 320 formed through the side of the fitting.

Operation The mechanical heart pump assembled as described is operated by a driving means connected as by a belt to the pulley 46. Other means of applying a driving force may also be employed including even a hand crank for emergcncics. Positive and negative sources of air pressure are connected to one or the other of the air chambers 98 through tubing 132. With these connections made, the camshaft rotational speed and the necessary operating air pressures are set. The connector nipples 252 and 292 are then ready to be connected to a blood supply source. Donor blood or a suitable fluid substitute may first be passed through the pump to check its operation. Upon proof of satisfactory performance the pump is filled with donor blood and is then ready for use.

The surgeon having made an incision within the body of a patient upon which heart surgery or other surgical Work is to be performed and having made cannulations within the proper arterial and venous vessels, makes connection between the patients arterial proper vessel and connector nipple 252 and between the patients proper venous vessel and the connector nipple 292.

As the camshaft 22 is rotated the earns 54 and 56 actuate the valves 108 to open and close the air chambers 98. The cams 54 and 56 alternately open one: or the other of the air chambers 98 to admit negative or positive air pressure to chamber 146. The camshaft 22 also rotates cam 52 which has cam surfaces 58 adapted to raise the cross arm 166 to actuate bleed-off valves 162. The cam surfaces 58 are positioned in relation to cams 54 and 56 so that the bleed-oif valves 162 are lifted at the end of the admission of the negative and positive pressures to chamber 146. In this manner the pressure supply sources are not required to eflect an atmospheric condition within chamber 146 prior to performing work on the sac 234.

The air pressure within chamber 146 is adapted to be evenly applied through the openings 206 in the sleeve 204 to expand or collapse the flexible sac 234. The difference of pressure between that within the sac 234 and that outside the sac is the working force for moving the blood through the heart sac and'valve assembly 148. A negative air pressure within chamber 146 causes the flexible sac 234 to expand. The pressure within the sac 234 being less than that beyond the check valves 222 causes the valve adjacent the inlet cannula 252 to open and causes the valve adjacent the outlet cannula 292 to close. When the pressure in the chamber 146 is reduced to atmospheric pressure the inlet valve 222 also closes and a quantity of fluid is held in the sac 234. When the pressure of the chamber 146 is increased the sac 234 is collapsed and the pressure within the sac being greater than that beyond the check valves 222 the inlet check valve is closed and the outlet valve is opened to pass blood into the filter chamber 16.

The flow of blood through the filter chamber '16 is as through a Weir flow gauge. The cushioning air within the top of. chamber 288 is controlled by the plug 318 adapted to open or close the air bleed-off passage 312. The blood flows through the filter sock 280 and hence through the connector nipple 292 to the patient.

The flow of blood through the heart pump makes contact with a minimum number of parts. The tricuspid valves 222 and the flexible sac 234 may be used as disposable elements with sterile valves and sacs kept in sterile wrappings for use when needed. Only the insert 242 of the base member 12 which includes the conduit 238 and the filter housing 16 need be sterilized, except of course for cannulae, tubing and other surgical instruments.

The cam operated valves and the flow passages 120,122, 124, and 12.6 are incident to the supply of a pressure source to the exterior of the flexible sac 234. The period during which the valves are open or closed is adapted to eflect a pumping action through the heart sac and valve assembly 148 which closely simulates the pumping pulsations of the human heart. The filter 280 is employed to hold and remove any blood clots which may pass through the heart sac and valve assembly 148. The transparent shell 302 about the filter sacs Z80 enables visual inspection of the flow of blood and assurance of an adequate and continuous supply of clone to the patient.

While numerous features are employed by the present heart pump to more closely simulate the action of the human heart it is to be understood that in emergencies many of these features may be eliminated. Thus the pump may be operated without filtering the blood through chamber 16, the air pressures need not necessarily be vented to the atmosphere, and While various camshaft driving means may be employed to control the admission of air pressure to the flexible sac 234, it is also even possible to operate the pump by holding the flexible sac in ones hand and by alternately squeezing and releasing the sac to assist the flow of blood therethrough. Such a pump in use in forward war Zones or disaster areas might well be called upon for use when no other operating means are available.

I claim:

1. A fluid pump adaptable for moving human blood and for simulating the pulsating pumping action of a human heart, said pump including a housing member having an air chamber formed therein, a flexible Walled tubular member extended through the end walls of said housing and through said air chamber to form a flow passage separate from said chamber, check valves disposed within the opposite ends of said flexible walled member and arranged to permit unidirectional fluid flow through said flow passage, a source of positive and negative air pressure connected to said air chamber through said housing member, pressure control valves mounted within said housing for controlling the admission of said air pressures, cam means mounted within said housing and adapted to control the actuation of said pressure control valves, and means driving said cam means to effect the controlled admission of positive and negative pressure to said air chamber and about said flexible walled member, said walled member being alternately collapsed and expanded by said pressures for forcing fluid through said check valves and said passage.

2. A fluid pump including a flexible walled tubular member having a fluid flow passage formed therethrough and inflow check valves disposed within opposite ends thereof, means for'alternately applying positive and negative airpressures externally of said flexible walled member for contracting and expanding said, tubular member and moving fluid therethrough via said check valves, and means operatively interconnected with said air pressure applying means for actuation therewith and for reducing the pressure condition about said flexible walled member to atmospheric pressure prior to the application of either positive or negative air pressures thereto.

3. The human heart simulating fluid pump of claim 1 wherein said check valves comprise flexible walled tricuspid valve members having flexible valve flaps responsive to pressure differentials for opening and closing without stretching, and having a perforated cylindrical member disposed within said air chamber and about said flexible walled tubular member to provide for a more uniform distribution of air pressures thereto and to limit the permissible expansion thereof.

4. The human heart simulating fluid pump of claim 1 including pressure relief valve means mounted within said housing and operatively disposed in communication With said air chamber and for engagement by said earn means, said cam means being disposed to actuate said relief valve means precedent the actuation of said press- 7 sure control valves to vent said air chamber to atmosphere pressure for the more efficient and responsive subsequent application of positive and negative pressures to said air chamber.

5. The human heart simulating fluid pump of claim 3 wherein said cam means includes separate cam members disposed for separate engagement with said negative and positive pressure control valves and a further separate cam member for engagement and actuation of said pressure relief valve means, said pressure relief valve means including a plurality of valve members simultaneously actuated by said last-mentioned cam member for more rapidly returning said air chamber to an atmospheric pressure condition.

References Cited in the file of this patent UNlTED STATES PATENTS 584,091 Leidich June 8, 1897 2,196,993 Kidder Apr. 16, 1940 2,291,912 Meyers Aug. 4, 1942 2,345,693 Wilson Apr. 4, 1944 2,405,734 Coe Aug. 13, 1946 2,450,751 Elwood Oct. 5, 1948 2,578,746 Scherger Dec. 18, 1951 2,682,057 Lord June 29, 1954 FOREIGN PATENTS 7,172 Great Britain of 1890

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