Abstract:
Fluid transfer device configured as a vacuum pump particularly suited for nondestructive transfer of fluids, including blood and blood constituents. Fluid transfer device used for assisting in the pumping of blood through a patient&#39;s heart for reducing the load on the heart, reducing forces and blood pressure on the inner walls of the heart is reduced. Examples are aortic assist device, a ventricular assist device, or artificial heart. Industrial applications include the pumping of fluids, including destructible fluids such as foodstuff with or without food constituents of various sizes within the foodstuff. Food and other fluids may be stored until they are dispensed. By use of a vacuum, the device is operated at no more than atmospheric pressure. A pre-charged pressure tank may be used, such as where fluid pressure of the pumped fluid, including backpressure of body fluids, where pressure greater than atmospheric is required to expel pumped fluid.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of application no. PCT/US2005/00477, filed Jan. 10, 2005, which claims the convention priority of U.S. patent application No. 60/534,685, filed Jan. 8, 2004, and each of which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The invention relates to fluid transfer devices. More particularly, the invention relates to nondestructive fluid transfer devices. Even more particularly, the invention relates to fluid transfer devices particularly suited for use in medical applications, such as in the pumping of blood. 
   BACKGROUND OF THE INVENTION 
   Fluid transfer devices such as pumps are known. 
   Artificial heart assistance devices, such as ventricular assist devices (VADs) that draw blood from one of the ventricles of the heart and push the blood through the aorta are known. 
   Known devices have proven unsatisfactory for pumping blood and other easily damaged fluids. 
   Known cardiac assist devices have many drawbacks related to the particular requirements of pumping blood, useful life, and so forth. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   It is an object of the invention to overcome the drawbacks of known devices. 
   A further object of the invention is to provide a fluid transfer device, such as a pump, usable for pumping fluids, such as liquids and gases. 
   A further object of the invention is to provide a fluid transfer device, such as a pump, usable for pumping destructible fluids, such as blood. 
   Another object of the invention is to provide a fluid transfer device which may be used internally or externally for assisting the heart. 
   A further object of the invention is to provide a nonshearing fluid transfer device, such as a pump. 
   A further object of the invention is to provide a fluid transfer device such as a pump, which may be used for pumping any destructible fluid, including viscous, semi-solid, and other fluids, including foodstuffs, such as salsa or chunky spaghetti sauce for which the user wants to maintain the integrity of the larger chunks of food, as well as condiments, or the dispensing of non-food product, such as soaps and shampoos, as the marketplace demands. 
   Yet another object of the invention is to provide a fluid transfer device which stores products until such time as the product is to be dispensed, such as for the dispensing of food, and other products, whether or not such products are readily degraded. 
   A still further object of the invention is to provide a fluid transfer device such as a pump, which inherently automatically continually cleans itself, in use. 
   A further object of the invention is to provide a fluid transfer device configured for pumping blood that automatically cleans itself. 
   A further object of the invention is to provide a medical pump which may be controlled by conventional pacemaker controls, in the case where the medical pump is used to assist the heart. 
   A still further object of the invention is to provide a fluid transfer device which may be used as a cardiac assist device, such as an aortic assist device or ventricular assist device (VAD), with or without the addition of one or more artificial heart valves. 
   Yet another object of the invention is to provide a fluid pump which may be used with an additional pump and requisite valving, power source, and controls to serve as an artificial heart. 
   Yet another object of the invention is to provide a medical device for transferring or pumping blood that has no entrapment areas, dead zones, or quiescent points that may lead to clotting and/or shearing of platelets and/or red blood cells (RBCs), for example, as in known devices. 
   A still further object of the invention is to provide a fluid transfer device, such as a pump, which avoids cross-fluid transfer or contamination. 
   A still further object of the invention is to provide a pump which prevents the evacuation of pressurized gas into the fluid being pumped. 
   Yet another object of the invention is to provide a pump which has a fail-safe mode selected to avoid destruction of the system in which the pump operates. 
   Another object of the invention is to provide a cardiac assist device which does not hamper heart blood flow in the case where the cardiac assist device suffers a loss of power. 
   Yet another object of the invention is to provide a cardiac assist device configured so that if a leak develops then a signal is sent to the user and/or the operation of the cardiac assist device is altered. 
   Another object of the invention is to provide a cardiac assist device configured so that in the event the cardiac assist device operation is altered or stops pumping blood (such as in the case of a power failure), less clotting of blood occurs than in known devices. 
   A further object of the invention is to provide a cardiac assist device configured so that sufficiently little clotting of a patient&#39;s blood occurs so as to enable the reduction or elimination of the patient&#39;s use of antiplatelet agents and/or anticoagulants than required by the use of known devices. 
   Another object of the invention is to provide a blood pump, such as a cardiac assist device, or an artificial heart, which causes little or no degradation of constituents of the blood being pumped. 
   Still another object of the invention is to provide a blood pumping device, such as a cardiac assist device, which substantially completely refreshes the volume of pumped blood and retains sufficiently little unpumped blood in its stopped or non-pumping state, so that there is substantially no accumulation of blood within the blood pump; i.e., blood which is not continually refreshed. 
   A further object of the invention is to provide a blood pump configured for minimizing the surface area of the pumping mechanism in contact with the blood being pumped, so as to minimize the surface area on which platelet accumulation and clotting may occur. 
   Another object of the invention is to provide a blood pump, such as a cardiac assist device, including a pumping element configured and selected so that a predetermined platelet accumulations occurs on a surface of the pumping device in contact with the blood being pumped, the predetermined accumulation being selected so as to prevent an undesirable excess accumulation of platelets which may lead to undesirable clotting of the blood being pumped. 
   A further object of the invention is to provide a blood pump which minimizes the volume of stagnant blood remaining in the pumping element of the pump during a non-pumping stage of a pumping cycle; i.e. a device which minimizes an umpumped volume resident in the blood pumping element of the blood pump. 
   Yet another object of the invention is to provide a cardiac assist device which requires no pacemaker. 
   Another object of the invention is to provide a cardiac assist device including one or more sensors capable of detecting one or both of the influx and outflow of blood into a ventricle of a heart, and/or the increase and decrease of the fluid pressure exerted by the blood in the heart to which it is connected; the detection by such sensor(s) being used to operate the cardiac assist device without an auxiliary control, such as a pacemaker. 
   Another object of the invention is to provide a method of implanting a cardiac assist device, such as an aortic or ventricular assist device, completely within a patient&#39;s torso or chest and, indeed, without the splitting of the sternum. 
   A further object of the invention is to provide a method of implanting a cardiac device, such as an artificial heart, completely within a patient&#39;s torso or chest. 
   Another object of the invention is to provide a cardiac assist device including a pumping element, such as a bladder, which includes a coating or layer or sensor adjacent the bladder and configured and selected so as to detect a fluid leak. 
   Another object of the invention is to minimize gas permeation into blood being pumped, as occurred in prior art gas-filled systems, the reduction of the likelihood of gas permeation being accomplished by, for example, the use of a negative pressure (e.g., the development of a vacuum) to draw in blood to be pumped, and the use of fluid at atmospheric pressure to pump out blood into the interior of the heart. 
   Another object of the invention is to provide a blood pump, such as a cardiac assist device, which reduces infection, thanks to its being fully implantable. 
   A further object of the invention is to provide a blood pump, such as a cardiac assist device, which may be configured for use in smaller patients, such as infants and preadolescents. 
   Another object of the invention is to provide a blood pump, such as a cardiac assist device, which may have a variable pumping rate and volume, which variable pumping rate and volume may be adjusted from outside the patient&#39;s body, so that, as an adult patient recovers, or as a child grows, for example, the pumping rate and volume may be increased, thereby eliminating the need to implant a new, larger device, as had been the case in the prior art. 
   Another object of the invention is to provide a blood pump, such as a cardiac assist device, having sufficiently low energy requirements that it may be operated by transformer coupled charging through the patient&#39;s skin. 
   A further object of the invention is to provide a blood pump, such as a cardiac assist device, which requires no percutaneous transfer of fluid energy or electrical energy in order to operate. 
   Yet another object of the invention is to provide a blood pump, such as a cardiac assist device, which includes a pulsatile pump, including a pulsatile pump with a variable pulsing rate. 
   A further object of the invention is to provide a blood pump, such as a cardiac assist device, in which one or both of the pumped fluid volume and the pumped fluid pressure may be varied. 
   Another object of the invention is to provide a blood pump, such as a cardiac assist device, which may be controlled by an implanted pacemaker inside or outside of the cardiac assist device housing and/or by pressure sensors configured for sensing blood pressure within a patient&#39;s heart, which pressure sensors may be provided inside or outside the housing of the cardiac assist device. 
   Another object of the invention is to provide a blood pump, such as a cardiac assist device, which includes an atmospheric pressure sensor, so that the pressure exerted by the pump may be varied to be substantially the same as atmospheric pressure to account for variations in atmospheric pressure, such as when the patient moves to a higher altitude. 
   Yet another object of the invention is to provide a blood pump, such as a cardiac assist device, which sufficiently minimizes stagnant blood contained within the pumping element of the device that no valve is required between the pumping element and the inside portion of the patient&#39;s heart to which the pumping device is fluidly connected. 
   Yet another object of the invention is to provide a blood pump which may be fluidly connected to one or more of the interior regions of a patient&#39;s heart, including, for example, the right ventricle, the left ventricle, the aorta, and so forth. 
   In summary, the invention includes an expandable expansion chamber, a hole or fluid connection provided in the expansion chamber, and a power unit operably associated with the expansion chamber for expanding the expansion chamber sufficiently to cause a fluid to be drawn into the expansion chamber through the hole or fluid connection. 
   The invention may likewise include an expansion chamber made of an elastic material. 
   The expansion chamber may be configured so that it has a normally unexpanded state; i.e. in its relaxed mode, it is in an unexpanded condition. 
   The power unit for expanding the expansion chamber may include a compressor. 
   A pressure tank may be fluidly connected with the compressor. 
   A valve or valves may be fluidly connected with one or more of the compressor, the pressure tank, and the expansion chamber for controlling the rate at which the expansion chamber expands and contracts, such as based on the blood flow requirements of a heart which is being assisted by the inventive device. 
   A control may be provided for varying the pumping rate of the pump or compressor. 
   The expansion chamber may include one or more lobes or fingers that draw in liquid and are filled with liquid as the expansion chamber expands, and which evacuate or expel liquid, such as blood, as the expansion chamber contracts or returns to its unexpanded state. 
   The lobe(s) or finger(s) are configured for sufficiently evacuating the fluid being transferred or pumped so that the expansion chamber is automatically continually cleaned; e.g., the fluid in all areas or regions of the expansion chamber is continually replaced and removed with newly drawn in fluid. 
   Relative terms such as left, right, first, second, up, and down are for convenience only and are not intended to be limiting. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  is a schematic cross sectional view of a fluid transfer device, such as a ventricular assist device, fluidly connected to the right ventricle of a heart for assisting in pumping blood through the heart; 
       FIG. 2  is a schematic cross sectional view of fluid transfer device, such as a ventricular assist device, fluidly connected to the left ventricle of a heart for assisting in pumping blood through the heart; 
       FIG. 3  is schematic cross sectional view of a further fluid transfer device, such as a ventricular assist device, shown fluidly connected to a ventricle of a heart for assisting in pumping blood through the heart; 
       FIGS. 4 and 5  show the embodiment of  FIG. 3 , in use; 
       FIG. 6  is a schematic cross sectional view of another fluid transfer device according to the invention similar to  FIG. 3  shown fluidly connected to a ventricle of a heart for assisting in the pumping of blood through the heart; 
       FIG. 7  is a schematic cross sectional view of another fluid transfer device according to the invention shown fluidly connected to both a ventricle and the aorta of a heart for assisting in the pumping of blood through the heart; 
       FIG. 8  is a schematic cross sectional view of another fluid transfer device according to the invention shown fluidly connected to the aorta of a heart for assisting in the pumping of blood through the heart; 
       FIG. 9  is a schematic cross sectional view of another fluid transfer device according to the invention shown fluidly connected to a portion of a heart for assisting in the pumping of blood through the heart; 
       FIG. 10  is a partial cross sectional view of the fluid transfer device of  FIG. 9 ; 
       FIG. 11  is a schematic cross sectional view of another fluid transfer device according to the invention that requires no pacemaker and is shown fluidly connected to a portion of a heart for assisting in the pumping of blood through the heart; and 
       FIG. 12  illustrates another embodiment of a fluid transfer device, such as an artificial heart, shown with four valves for use in complete heart replacement. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a fluid transfer device or pump according to the invention, in use as a ventricular assist device (VAD)  10 . 
   VAD  10  of  FIG. 1  is shown in use on a heart  12  having a left ventricle  14  and a right ventricle  16 . VAD  10  is shown in use as a right ventricular assist device (RVAD), shown fluidly connected to the right ventricle  16  of the heart. 
   VAD  10  may be provided with a housing  14 , which may be substantially rigid. Housing  14  may be made of a material selected for a compatibility with tissue. 
   The fluid connection of RVAD  10  to the heart may be made with a connector  18  compatible with heart tissue, such connectors  18  being known. 
   A pacemaker control  24  for an RVAD may be used for controlling the timing of the RVAD in conjunction with the beating of the heart, as will be described further below. 
   An expansion chamber  30  having an expanded state  32  and an unexpanded state or mode  36  may be provided within housing  14 . In expanded state or mode  32  the expansion chamber will be substantially filled with blood and in the unexpanded or resting state  36  the expansion chamber may be substantially empty. 
   A compressor or pump  42 , such as an electric vacuum pump, may be provided for pressurizing a pressure tank  44  by pumping a fluid, such as a gas into pressure tank  44 . A valve  46 , which may be controlled by the pacemaker control  24  and associated control(s), such as an integrated chip  48  or other electronic controls, as will be readily understood, may serve to regulate the flow of the fluid located in the interior  48  of the housing for controlling the expansion and contraction of the expansion chamber  30 . 
   A power source  50 , such as a battery contained within housing  14 , or an external battery or pneumatic or vacuum supply, may be used to power compressor  42 . Alternatively, an externally controlled and operated vacuum and vent source may be used to expand and contract the chamber  30 . 
   Battery  50  may be externally recharged via a body port connection  54 . 
   Expansion chamber  30  may have one or more lobe-shaped or finger-like extensions. Three(3) finger-like extensions are shown. One opening  58  of expansion chamber  30  may be fluidly connected with connector  18  and, thus, fluidly connected to the user&#39;s heart. 
   In use compressor  42  draws in fluid, such as gas, contained in interior  48  of the housing, compresses the fluid, and forces the fluid into tank  44 , as will be readily appreciated. In this manner, as the amount of gas in interior  68  is reduced, the pressure on the exterior of expansion chamber  30  is reduced, and expansion chamber  30  expands to its expanded condition  32 , thereby drawing blood into expansion chamber  30 . At the appropriate time as dictated by the heart beat, control  24  causes blood to be discharged from expansion chamber  30  through hole or fluid connection  58  synchronous with the discharging of the heart chamber. The blood is discharged by opening valve  46  fluidly connected to tank  44 , thereby releasing pressurized gas from tank  44 , refilling interior  48 , thus raising the pressure therein, and causing expansion chamber  30  to return to its unexpanded state  36 . The expansion chamber may be configured so that its natural state is unexpanded state  36 , the elasticity of the material of expansion chamber assisting/causing the expansion chamber to return to its unexpanded state  36 . In this manner, the expansion chamber returns to its unexpanded state should there by an unwarranted interruption in the operation of the VAD, such as in the case of a power failure. 
   Quite simply, the timing of the valve may be controlled by a known sense/pace pacemaker. The rate may automatically adjust discharge valve firing as needed. This may be termed a “pulsatile” type device. 
   The tank may be at atmospheric pressure so that there would not be a positive pressure within the user&#39;s body greater than atmospheric, in use. 
   As shown, RVAD  10  may be used without an artificial valve in conjunction with the natural valves of the heart, and need only be connected in one place on the heart, as appropriate, with known connective material. Beating (pumping) in sequence with the normal rate of the heart as fired by the pacemaker that senses heart rate change varies the operation of the compressor and/or the valve accordingly. 
     FIG. 2  illustrates a left ventricular assist device (LVAD)  100  controlled by a pacemaker  124 , and other controls depending on the configuration of the like components. 
     FIG. 3  is schematic cross sectional view of a further fluid transfer device  130 , such as a ventricular assist device, shown fluidly connected to a ventricle of a heart for assisting in pumping blood through the heart. 
   Cardiac assist device  130  is similar to the embodiment of  FIGS. 1 and 2 , with the addition of a further cavity  132  within housing  131 . Further cavity  132  may be used to divide the interior of housing  131  into an inner cavity  133  and an outer cavity  135 . As shown and described in greater detail with reference to  FIGS. 4 and 5 , wall  132  defining inner cavity  133  may include one or more curved regions  138 ,  142 , and  144 . Regions  138 ,  142 , and  144  may be disclosed and configured for receiving expandable chamber or bladder  30  in its expanded conditions. For example, lobes or fingers or extensions  158 ,  162 , and  164  may expand into the regions defined by respective ones of portions  138 ,  142 , and  144 . 
   In use, chamber  30  need not expand into contact with the inner wall of chamber  132 . However,  132  may be configured so as to control expansion of chamber  30 , as needed, in use. 
     FIG. 4  shows chamber or bladder  30  in an unexpanded condition at atmospheric pressure with valve  58  in a closed position. 
     FIG. 5  shows chamber  30  in what may be termed a fully expanded condition having fully expanded lobes  168 ,  172 , and  174  corresponding to respective ones of unexpanded lobes  158 ,  162 , and  164 . 
   Appropriate controls, such as a pacemaker, dedicated control chip, and the like may be provided as will be readily understood. For example, one or more valves  184  may be provided for controlling the accumulation and release of a fluid into and from pressure tank  44  into and from the inner cavity  133  for assisting in the expansion and contraction of chamber  30 . 
   Quite simply, as in the previous embodiment, pump  42  may force a fluid provided in interior  133  in between the exterior of chamber  30  and the lobed inner wall  132  for developing a pressure less than atmospheric pressure within cavity  133 ; i.e. for developing a vacuum therein and, thus, causing chamber  30  to expand and draw in blood from the portion of the heart to which the device  130  is attached, in use. Then, when the drawn in blood is to be sent back into the heart for assisting in the pumping of blood in a patient, for example, valve  184  is open to allow release of fluid from pressure tank  44 , to pressurize fluid exiting through valve  44  and fill and pressurizing cavity  133  so that, with the assistance of atmospheric pressure, the blood is forced out of expansion chamber  30  into the heart, in use. Pacemaker  124  and other appropriate controls will govern the expansion and contraction of chamber  30 , as will be readily understood. 
     FIGS. 4 and 5  show the embodiment of  FIG. 3 , in use. 
     FIG. 6  is a schematic cross sectional view of another fluid transfer device  200  according to the invention similar to  FIG. 3  shown fluidly connected to a ventricle of a heart for assisting in the pumping of blood through the heart. 
   Cardiac assist device  200 , shown in use as a ventricular assist device, is similar to the embodiments of  FIGS. 3-5 . Cardiac assist device  200  may include recharger  134  for recharging a battery for powering device  200 , recharger  134  being at a location remote from housing  131 . 
   Likewise, pacemaker  124  may be located at a location distant from housing  134 , as shown in  FIG. 6 , as will be readily appreciated. 
     FIG. 7  is a schematic cross sectional view of another fluid transfer device  220  according to the invention shown fluidly connected to both a ventricle and the aorta of a heart for assisting in the pumping of blood through the heart. 
   Fluid transfer device  220  may be used for patients requiring both a ventricular assist device  224  and an aortic assist device  234 . 
   Pacemaker  124  may be used to govern the operation, along with appropriate controls, as will be readily understood. Likewise, recharger  134 , shown in a remote location, may be used to recharge a battery used for powering both devices, or for recharging respective batteries found in each one of ventricular assist device  224  and aortic assist device  234 . 
     FIG. 8  is a schematic cross sectional view of another fluid transfer device  240  according to the invention shown fluidly connected to the aorta of a heart for assisting in the pumping of blood through the heart. 
   Device  240  of  FIG. 8  may be used as an aortic assist device  240 , as shown. Pacemaker  124  may be used for controlling operation, and recharger  134  may be used for recharging an implanted battery housed within the casing of aortic assist device  240 , as will be readily understood. Appropriate controls may be located within the housing of aortic assist device  240 , outside the housing, and fully implanted, as patient requirements dictate, as in the other embodiments. 
     FIG. 9  is a schematic cross sectional view of another fluid transfer device  250  according to the invention shown fluidly connected to a portion of a heart for assisting in the pumping of blood through the heart. 
   Fluid transfer device  250  may be termed a ventricular assist device, as it is shown connected to a ventricle of a patient&#39;s heart, as in other embodiments described herein. 
   Ventricular assist device  250  may include an opening or fluid connection  252  having no valve. Thanks to the configuration of expandable chamber or bladder  30  and the configuration of fluid connection  252 , sufficient blood which had been drawn into the interior of chamber  30  during the expansion of chamber  30  will be exited or pushed out of the interior of chamber  30  under the influence of the pressurized fluid in the pressure tank and the pressure exerted by atmospheric pressure so that substantially no stagnant blood will remain within chamber  30 . In other words, sufficiently little stagnant blood will remain in chamber  30  so as to lead to clotting. It is likewise contemplated that in a region  253 , such as the illustrated narrowing region  253  of bladder  30 , the bladder or expandable chamber  30  may be configured so that in its unexpanded condition, narrowed portion  253  completely closes and functions as a valve. In that manner, no additional valve need be used in the region of fluid connection  252 . 
     FIG. 10  is a partial cross sectional view of the fluid transfer device of  FIG. 9 . 
   The wall or inner housing defining inner cavity  133  may be provided with one or more throughholes or perforations  254  and  256 . A plurality of perforations  254  and  256  may be used to ensure that chamber  30  is expanded evenly, and to reduce the likelihood that a portion of chamber  30  might block a single hole, in use. In this manner, the negative pressure developed by the pump may be developed in an inner volume  258  for thus developing a negative pressure within the inner volume  262  defined within lobed wall  132  defining a lobed cavity and outside of lobed expandable chamber  30 . 
   As in other embodiments of the invention, a sensor may be provided for determining whether or not there is a fluid leak within cavity  262 ; i.e. a fluid leak which might correspond to fluid leaking out of expandable chamber  30 , in use. In the case of ventricular assist device  250 , sensor  264 , may sense the presence of leaked blood. Sensor  264  may sense the presence of blood by the use of a photosensor detecting a change in light or color within cavity  262  in the presence of blood. Sensor  264  may also include a moisture sensor or hygrometer for detecting a change in moisture content or relative humidity corresponding to the presence of a leaked fluid. Still further, sensor  264  may include a chemical sensor detecting the presence of a chemical or change in chemical composition. Sensor  264  may likewise include an electrical sensor for detecting a change in electrical resistance, for example. These are merely examples and are not intended to be limiting. 
   In this manner, an inner wall  268  may be treated or coated with a chemical for indicating the presence of a leak, such as by a change in chemical properties which may be detected by sensor  264 . 
     FIG. 11  is a schematic cross sectional view of another fluid transfer device according to the invention that requires no pacemaker and is shown fluidly connected to a portion of a heart for assisting in the pumping of blood through the heart. 
   Device  270  of  FIG. 11  may be used as a ventricular assist device, as shown. Device  270  may be particularly suited for compact or fully implanted situations. Device  270  may include a combined compressor and pressure tank or accumulator  280 . Combination compressor and pressure tank  280  may include a pump or compressor  282  in one portion and a pressure tank  284  in another portion. 
   Controls, such as an electronic control, may be provided. 
   A valve  294  may fluidly connect compressor  282  pressure tank  284 , and inner cavity  295 , for example. 
   A perforated wall  132 , as shown in  FIGS. 10 , may be provided so that the development of a vacuum in cavity  295  may serve to develop a respective vacuum in cavity  297  for expanding expandable chamber  30 , along the lines described above. 
   To further reduce size requirements, a sensor  296 , such as a pressure sensor, may be provided that is configured to substitute for the use of a pacemaker. Pressure sensor  296  may be configured to sense an increase in the blood pressure within a patient&#39;s heart, in use, so that thanks to control  274 , the overall combination of elements will serve to function in concert with the pumping of the heart to assist in such pumping. Thanks to the use of an appropriate pressure sensor which detects changes in pressure transmitted through the fluid connection between the heart and pressure sensor  296 , such fluid connection including the fluid (i.e. the blood) within chamber  30  and the fluid within cavity  297 , it can be readily determined at which points in time the control  274  should cause the compressor to evacuate cavity  295  and, hence, lower the pressure below atmospheric pressure, for drawing blood into chamber  30  by the expansion of chamber  30 , for example. Such pressure sensors and timing would be readily understood. 
     FIG. 12  illustrates another embodiment of a fluid transfer device, such as an artificial heart, shown with four valves for use in complete heart replacement. 
   Fluid transfer device  300  may be used as an artificial heart  300 , as shown. Artificial heart  300  may include a housing  310  including a first subhousing  312  and a second subhousing  314 . First and second expandable lobed chambers  316  and  318  may be provided in respective housings  312  and  314 . 
   A first fluid connection  320  may be provided for fluidly connecting chamber  316  with the exterior of cavity  312 . First fluid connection  320  may include respective right and left fluid connections  322  and  324 , each having respective left and right fluid valves  326  and  328 . 
   In a similar manner, lobed chamber  318  may include a fluid connection  340  including left and right fluid connections  342  and  344 , each such fluid connections  342  and  344  having respective left and right valves  346  and  348 . 
   In use, fluid flow would be in respective directions represented by arrows  380 ,  382 ,  386  and  388 , governed by controls  370  which dictate the manner in which respective valves  324 ,  326 ,  346 , and  348  are opened and closed. As will be readily appreciated, depending on the manner in which artificial heart  300  is attached to a patient&#39;s veins and arteries (e.g., at which ones of fluid connections  322 , 324 , 344 , and  344 ) the artificial heart recipient&#39;s veins and arteries are being attached, one or more of valves  326 ,  328 ,  346 , and  348  may be actively controlled by control  370 . One or more of the valves may be controlled by the expansion of chambers  316  and  318 , depending on the intended use. 
   To enhance compactness, one or more combined compressors and pressure tanks  390  may be used; or, the pump  390  may be used and associated valve  394  so that interior  395  of subhousing  312  may be used as the pressure tank, as described in connection with other embodiments. It will be appreciated that the various controls may be used as in the other embodiments. 
   Any of the embodiments may be monitored from outside a patient&#39;s body, in use. 
   Any of the embodiments may be provided with variable pumping rates and volumes, pulsatile pumping, and other fine-tuning of the pumping of blood, in use, in order to enhance the operation of any of the embodiments, and so that any of the embodiments may be used for children so that the rate may be varied as they grow in stature, and for adult patients, so that the heart pressure and volume and rate may be increased as the patient convalesces, as deemed necessary. 
   It is further contemplated that any of the embodiments appropriate coatings may be provided on any of the interior and exterior of the expandable chambers and/or on the interior of the rigid housing or rigid lobed wall defining an outermost extent of the expansion chamber so as to eliminate platelet accumulation, reduced sheer, indicate fluid leaks, and enhance compatibility, and the like. 
   Any of the embodiments may be configured to minimize the surface area of the expandable chamber so as to minimize the surfaces on which platelets may accumulate, in the case where embodiments are used as cardiac assist devices or for pumping blood. 
   Any of the embodiments may be configured to minimize the stagnant (i.e. unpumped) volume of the material being pumped. 
   A pacemaker may be eliminated in respective embodiments, depending on the intended use. 
   In any of the embodiments by the use of atmospheric pressure to discharge the fluid there is a reduced likelihood that gas will permeate the fluid being pumped, as has been the case in prior art gas-filled systems. 
   It will be appreciated that devices in accordance with the invention may be used to replace entire chambers of the heart with the use of artificial inlet and outlet valves, as required. 
   It is further contemplated that two(2) of these fluid transfer devices or pumps according to the invention, along with artificial heart valves, as required may be used to completely replace a patient&#39;s heart. 
   The pump may be located outside the body and used to pump blood. 
   In the case of children or certain conditions, the valve may be partially open during the compression stage. 
   Additional control(s), such as a dedicated chip, may be provided. 
   One or more of the pump, compressor, pressure tank, battery, battery charger, controls, and the like may be located inside the housing, outside the housing and inside the patient&#39;s body, and/or outside of the patient&#39;s body, depending on patient requirements, for example, and other considerations. 
   While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and as fall within the scope of the invention.