Abstract:
A surgical pump suitable for bodily fluids, normally blood, usable in the course of surgical interventions as an alternative to the traditional CPB (cardio pulmonary bypass) making use of external blood pumps. It consists of an intake cannula which is inserted with its fist (distal) end in a first vessel, an outflow cannula coaxial for some length with, and larger than the first cannula, which is inserted with its first (distal) end in a second vessel, both second ends of the coaxial cannulas being connected with a pump housing having an inlet for the inner cannula and outflow windows for the outer cannula, a rotor impeller housed in the housing and connected with an electric motor rotating coaxially below the pump housing, the housing having inner and outer passageways which allow inflow, change of flow direction (reversal) and outflow of the fluid, thus producing two coaxial counter flowing flows in the coaxial cannulas. The pump can be used making use of a single portal. Inflatable balloons can be used to stabilize the cannulas in situ and to stabilize the walls of the organs or vessels where the cannulas are inserted.

Description:
RELATED APPLICATIONS  
       [0001]     This application is a divisional application of co-pending U.S. patent application Ser. No. 09/462,656, filed Jan. 14, 2000, which is 371 of PCT/US97/18674, filed Oct. 14, 1997, which is a continuation-in-part of U.S. patent application Ser. No. 08/933,566, filed Sep. 19, 1997, now U.S. Pat. No. 6,083,260, which is a continuation-in-part of U.S. patent application Ser. No. 08/891,456, filed Jul. 11, 1997, now U.S. Pat. No. 6,123,725. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention is generally directed to related apparatus and methods for the circulation of bodily fluids through the use of a reverse flow pump system. More particularly, the present invention relates to the transport of fluids between various body regions and the increased stabilization of body organs.  
       BACKGROUND OF THE INVENTION  
       [0003]     During most surgical procedures, bodily fluids are directed and transferred to various locations with the assistance of artificial pumping apparatus. Major operations such as heart surgery have been accomplished by procedures that require general anesthesia, full cardiopulmonary bypass (CPB), and complete cessation of cardiopulmonary activity. For example, during open heart surgery, circulation must be maintained while delicate work is performed on fragile blood vessels.  
         [0004]     As with most major operations, open heart surgery typically requires weeks of hospitalization and months of recuperation time for the patient. The average mortality rate with this type of procedure is low, but associated with a complication rate that is often much higher. While very effective in many cases, the use of open heart surgery to perform various surgical procedures such as coronary artery bypass grafting (CABG) is highly traumatic to the patient. These procedures require immediate postoperative care in an intensive care unit, a period of hospitalization for at least several days, and an extended recovery period. In addition, open heart procedures require the use of CPB which continues to represent a major assault on a host of body systems. For example, there is noticeable degradation of mental faculties following such surgeries in a significant percentage of CABG patients in the United States. This degradation is commonly attributed to cerebral arterial blockage from debris and emboli generated during the surgical procedure. At the same time, the dramatic increase in the life expectancy of the general population has resulted in patients that are more likely to be older and sicker, with less cardiovascular, systemic, and neurologic reserve. As a consequence, inflammatory, hemostatic, endocrinologic, and neurologic stresses are tolerated much less by a significant number of patients today, and play a more significant role in CPB-induced morbidity.  
         [0005]     The CABG procedure generally involves open chest surgical techniques to treat diseased vessels. During this procedure, the sternum of the patient is cut in order to spread the chest apart and provide access to the heart. The heart is stopped, and blood is thereafter cooled while being diverted from the lungs to an artificial oxygenator. In general, a source of arterial blood is then connected to a coronary artery downstream from the occlusion. The source of blood is often an internal artery, and the target coronary artery is typically among the anterior or posterior arteries which may be narrowed or occluded.  
         [0006]     The combined statistics of postoperative morbidity and mortality continue to illustrate the shortcomings of CPB. The extracorporeal shunting and artificially induced oxygenation of blood activates a system wide roster of plasma proteins and blood components in the body including those that were designed to act locally in response to infection or injury. When these potent actors are disseminated throughout the body without normal regulatory controls, the entire body becomes a virtual battleground. The adverse hemostatic consequences of CPB also include prolonged and potentially excessive bleeding. CPB-induced platelet activation, adhesion, and aggregation also contribute to a depletion in platelet number, and is further compounded by the reversibly depressed functioning of platelets remaining in circulation. The coagulation and fibrinolytic systems both contribute to hemostatic disturbances during and following CPB. However, the leading cause of morbidity and disability following cardiac surgery is cerebral complications. Gaseous and solid micro and macro emboli, and less often perioperative cerebral hypoperfusion, produce neurologic effects ranging from subtle neuropsychologic deficits to fatal stroke. Advances in computed tomography, magnetic resonance imaging, ultrasound, and other imaging and diagnostic techniques have added to the understanding of these complications. But with the possible exception of perioperative electroencephalography, these technologies do not yet permit real time surgical adjustments that are capable of stopping a stroke in the making. Doppler and ultrasound evaluation of the carotid artery and ascending aorta, and other diagnostic measures, can also help identify surgical patients at elevated risk for stroke which are among the growing list of pharmacologic and procedural measures for reducing that risk.  
         [0007]     CPB also affects various endocrine systems, including the thyroid gland, adrenal medulla and cortex, pituitary gland, pancreas, and parathyroid gland. These systems are markedly affected not only by inflammatory processes, but also by physical and biochemical stresses imposed by extracorporeal perfusion. Most notably, CPB is now clearly understood to induce euthyroid-sick syndrome which is marked by profoundly depressed triiodothyronine levels persisting for days following cardiothoracic surgery. The efficacy of hormone replacement regimens to counteract this effect are currently undergoing clinical investigation. By contrast, levels of the stress hormones epinephrine, norepinephrine, and cortisol are markedly elevated during and following CPB, and hyperglycemia is also possible.  
         [0008]     Alternatives to CPB are limited to a few commercially available devices that may further require major surgery for their placement and operation such as a sternotomy or multiple anastomoses to vessels or heart chambers. For example, some present day devices used in CPB may require a sternotomy and an anastomosis to the ascending aorta for placement. The main drawbacks of these devices include their limited circulatory capacity which may not totally support patient demands, and their limited application for only certain regions of the heart such as a left ventricular assist device. These types of devices typically require direct access to the heart region and open heart surgery. Other available devices that permit percutaneous access to the heart similarly have disadvantages such as their limited circulatory capabilities due to the strict size constraints for their positioning even within major blood vessels. Moreover, the relative miniaturization of these types of devices present a high likelihood of mechanical failure. In further attempts to reduce the physical dimensions for cardiac circulatory apparatus, or any other bodily fluid transport system, the flow capacity of these devices are significantly diminished.  
         [0009]     It would therefore be desirable to provide other less traumatic and more efficacious methods and techniques for controlling fluids while performing heart surgery or any other type of major operation. It would be particularly desirable if such techniques did not require the use of CPB or a sternotomy. It would be even more desirable if such apparatus and techniques could be performed using thoracoscopic methods that have been observed to decrease morbidity and mortality, cost, and recovery time when compared to conventional open surgical procedures.  
         [0010]     Another significant disadvantage of surgical procedures on the heart and other fluid transport systems within the body is their inherent structural instability. The relative flexibility and wide range of movement of organ walls, cavities or the like often complicates delicate procedures that demand a stable operating platform. For example, the instability of unsupported cardiac walls, particularly when the heart is still beating, present significant challenges to the surgeon in performing CABG or other similar procedures. A variety of tools or probes are currently used in an attempt to minimize the movement of a tissue wall, organ or cavity wall, such as the exterior heart wall, and is a well recognized method used during CABG surgery on a beating heart. For example, a probe may be used that consists of a forked pedal placed directly onto the surface of a beating heart. These devices and other similar implements simply compress the outside wall of the heart or any other relatively unstable body surface to reduce its movement, and allows a surgeon to operate in a slightly more controlled environment. Other commonly used tools that provide similar functions may consist of a series of suction cups that uses suction force to suspend or hold areas surrounding the external surface of a surgical site in order to reduce undesirable movement. These and other known devices generally hold or immobilize only the external surface of an organ or unsupported wall to reduce movement at the surgical site.  
         [0011]     During cardiac surgery, the heart is either still beating or immobilized entirely which requires further use of CPB. In the past, bypass surgery on a beating heart was limited to only a small percentage of patients requiring the surgical bypass of an occluded heart vessel. These patients typically could not be placed on CPB to arrest the heart, and were operated on while the heart kept beating. Meanwhile, patients whose hearts were immobilized and placed on CPB often suffered major side effects as previously described.  
         [0012]     The medical community is currently performing more beating heart bypass surgery in an effort to avoid the use of artificial heart-lung machines. The need for apparatus and equipment to minimize the heart movement during surgery is ever increasing but very limited to a small number of devices designed for this specific application. Many devices in use today affect the heart motion by only interacting with its external wall while the inside wall of the heart is free to move about which does not create a motionless surgical site. In bypass surgery, it is particularly desirable to maintain the operating site relatively motionless during the suturing of these small vessels. Any compromise in the quality and integrity of the sutured vessel results in immediate or delayed complication that may be life threatening or require additional surgery. It is therefore desirable to perform beating heart surgery at surgical sites that remain relatively motionless. In order to achieve relative stability with beating heart surgery, it is desirable for the operation site be held relatively motionless by stabilizing both the outside and inside surfaces of the organ, or fixing the external and internal surfaces of a body wall. The stabilization mechanism should also not interfere significantly with the internal flow of fluids such as blood, or interfere with blood circulation by affecting heart rhythm through the application of any significant force to the heart wall, particularly when a patient has a low threshold for manipulating the external wall of the heart. Any significant manipulation of the heart itself may lead to heart fibrillation or arrhythmia, and presents an increased risk to the health of the patient.  
       SUMMARY OF THE INVENTION  
       [0013]     The present invention provides a reverse flow pump system that transports fluid between different regions within the body in order to support a wide variety of surgical procedures. Another object of the present invention is to provide apparatus and methods for the stabilization of surgical sites during procedures such as heart surgery.  
         [0014]     In one embodiment of the invention, a reverse flow pump for transporting bodily fluids is provided with concentric inner and outer passageways, and an interior compartment that includes a rotor to reverse the directional flow of fluid relative to the pump. A hubless rotor is also provided for efficiently directing the flow of fluid within conduits adjoining the inner and outer passageways of the pump.  
         [0015]     Another embodiment of the present invention provides a thoracoscopic method for cardiac support during surgical procedures. More particularly, the thoracoscopic methods described herein are directed to unloading the heart, and partially or totally stopping the heart to allow procedures to be performed externally on or internally within the heart while the chest may remain unopened. The heart may also be unloaded by using a left ventricular blood pump, or a left and a right ventricular blood pump for venous and arterial circulation.  
         [0016]     Another variation of the present invention is directed to an endovascular method and system for preparing the heart for surgical procedures, and particularly for unloading the heart, partially or totally stopping the heart. A reverse flow blood pump system may be passed through a conduit and positioned in a heart chamber or a vessel in preparation to completely or partially stop the heart in order to operate on the organ. Another object of the present invention is to provide a single conduit for introducing a pump system at operative sites in the body with the conduit inserted in the body through a portal of minimal size formed in tissue of a body wall, and engaging an external surface of a vessel or the heart to limit any significant bleeding. An inflow cannula may further be disposed in a heart chamber to direct blood from the heart into a region surrounding the conduit. A single anastomosis may be used to provide a path for both the inflow and the outflow of a blood pump.  
         [0017]     An additional object of the present invention is to provide an apparatus which provides cardiac support during open chest heart surgery, or any other surgical procedure that requires total or partial unloading of the patient&#39;s heart or complete or partial cessation of heart function, and is less traumatic and invasive to the patient than current apparatus used today.  
         [0018]     In yet another embodiment of the present invention, a method and associated apparatus for cardiac support is directed to extravascular or trans-valvular procedures that may require only one incision into a major blood vessel such as an aorta. The apparatus may include an elongated inner cannula inserted through a portal formed in a major blood vessel or heart chamber that is disposed coaxially with an outer conduit. A reverse flow pump may be disposed between the proximal openings on the inner cannula and the outer conduit which pumps blood delivered by the inner cannula to the outer conduit. The distal openings on the inner cannula and outer conduit may be spaced apart and disposed either in different blood vessels or transvalvularly in the heart so that blood flowing into the distal opening of the inner cannula may be delivered through the distal opening on the outer conduit located downstream or proximal from the distal opening of the inner cannula. A portal may also be formed in the aorta with the distal opening on the outer conduit extended therethrough. The inner cannula may further be positioned through the aortic valve and disposed inside the left ventricle to transport blood deposited in the aorta thereby unloading the left ventricle. Optional balloons may also be selectively inflated on the outside surface of the inner cannula or outer conduit which act to seal off the passageway between the sides of the blood vessel and the cannula, to cool adjacent tissue, or to deliver drugs to adjacent tissue.  
         [0019]     It is another object of this invention to provide stabilization of the external and internal surfaces of the heart wall during cardiac surgery while maintaining normal cardiac and circulatory functions. Another object of the present invention to substantially immobilize the external and internal walls of the heart using an inflatable stabilization balloon or a mechanical structure that supports the inner wall of the heart to provide additional stabilization of a surgical site, and using a forked tool to hold the external surface of the heart to provide stabilization of the outer wall of the heart. Another object of the present invention is to provide a stabilization balloon or a mechanical structure in combination with a flow cannula and pump to allow for normal blood circulation to assist in heart functions. A catheter may further be included comprising an elongated flexible shaft portion with a miniature blood pump and stabilization apparatus positioned at its distal end portion. The catheter may further include a multilumen arrangement to provide separate paths for inflation of a stabilization balloon, a pump drive mechanism, and monitoring or diagnostic apparatus. These and other objects and advantages of the present invention will become more apparent from the following description and accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]      FIG. 1  is an exploded perspective sectional view of a reverse flow system generally showing the reverse flow pump in relation to an inner and an outer conduit which direct and control the flow of fluids between different body regions.  
         [0021]      FIG. 2  is a sectional side view of the pump portion of a reverse flow system illustrating the directional change in fluid flow.  
         [0022]      FIG. 3  is an exploded perspective view of a reverse flow pump assembly including a pump driving system and positioning apparatus.  
         [0023]      FIG. 4  is a perspective view of an assembled reverse flow pump similarly shown in  FIG. 3 .  
         [0024]      FIGS. 5A-5D  are exploded perspective views of the housing and the inlet compartment for a reverse flow pump.  
         [0025]      FIGS. 6A and 6B  are distal side views of the reverse flow pump unit.  
         [0026]      FIGS. 7A-7C  are side and sectional views of a rotor for a reverse flow pump having a hub and blade portions.  
         [0027]      FIG. 8  is a perspective view of a hubless rotor for a reverse flow pump having a central passageway and blade portions.  
         [0028]     FIGS.  9 A-E are sectional views of various pump housings with their respective rotors and relative flow patterns.  
         [0029]      FIG. 10  is a simplified sectional side view of the drive unit for a reverse flow pump assembly.  
         [0030]      FIG. 11  is a simplified perspective view of a conduit formed by conventional techniques showing a clamped vessel and an attached conduit.  
         [0031]      FIG. 12  is a simplified sectional perspective view of a reverse flow pump assembly positioned within the conduit shown in  FIG. 11 .  
         [0032]      FIG. 13  is a simplified sectional side view of a reverse flow system where the pump assembly is positioned external to a blood vessel graft.  
         [0033]      FIG. 14  is a sectional view of a heart and its respective chambers and valves including the placement of an inner cannula and an outer conduit for assisting the transport of blood between different regions of the heart.  
         [0034]      FIG. 15  is sectional view of the heart showing a portal formed in the aorta for the placement of the outer conduit and the inner cannula which also includes inflatable balloons positioned in different regions of the heart.  
         [0035]      FIG. 16  is a sectional view showing the positioning of the inner cannulas and outer conduits of multiple circulatory support systems in different heart regions.  
         [0036]      FIG. 17  is a sectional view showing a dual circulatory support system supporting both the left and right side of the heart.  
         [0037]      FIG. 18  is a sectional view of a dual circulatory support system further including inflatable balloons and ports formed along the inner cannula that are positioned in different regions of the heart.  
         [0038]      FIG. 19  is a sectional view of the heart illustrating a circulatory support and stabilization apparatus embodying multiple aspects of the present invention including at least one inflatable balloon in a heart region, a balloon within a heart chamber having another surrounding inflatable balloon, and further including additional openings formed along the inner cannula.  
         [0039]      FIG. 20  is a sectional side view of a stabilization balloon with an inflation conduit.  
         [0040]      FIG. 21  is a stabilization system provided in accordance with the present invention that is introduced through a femoral artery.  
         [0041]      FIG. 22  is an illustration of the exterior view of the heart and a forked instrument used to stabilize an external area of the heart.  
         [0042]      FIG. 23  is a partial sectional view of the heart and a stabilization system used in cooperation with an intravascular pump.  
         [0043]      FIG. 24  is a partial sectional view of the heart and a stabilization system used in cooperation with an extracorporeal pump.  
         [0044]      FIG. 25  is a simplified sectional view a coaxial lumen assembly for a centrifugal fluid pump.  
         [0045]      FIG. 26  is a simplified sectional view of a Y connector embodiment of a dual lumen fluid transport device with a coaxial lumen assembly for an axial fluid pump.  
         [0046]      FIG. 27  is a simplified sectional view of a Y connector embodiment of a dual lumen fluid transport device with a centrifugal pump.  
         [0047]      FIG. 28  is a simplified sectional view of a Y connector embodiment of a dual lumen fluid transport device with a roller pump. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0048]     In  FIG. 1 , a fluid transport system is provided in accordance with one aspect of the present invention. The fluid transport system  10  may comprise an inner cannula  20  coaxially aligned with an outer conduit  30 , and a reverse flow pump  50 . The reverse flow pump  50  may direct bodily fluids such as blood through the inner cannula  20  to the outer conduit  30 , and then throughout other regions of the body. By using such an arrangement, only one portal  91  may be required to be formed in a blood vessel to support various surgical procedures. The inner cannula  20  may be arranged to function as an inlet conduit designed to assist the delivery of blood and other bodily fluids to the pump  50  while the outer conduit  30  may transport fluid away from the pump  50 . It should be understood, however, that the relative functions of the inner cannula and outlet conduit may be exchanged depending on the desired positions of the distal opening  22  of the inner cannula  20  and the distal opening  32  of the outer conduit  30 , and the direction of flow controlled by the pump  50 .  
         [0049]     The inner cannula  20  in  FIG. 1  may be formed with a distal opening  22  and a proximal opening  24 . When positioned for use during heart surgery, for example, the distal opening  22  may be disposed in a heart chamber through major blood vessels such as the left ventricle. As a result, blood entering the distal opening  22  of the inner cannula  20  is transported to the pump  50  which then directs the blood through the outer conduit  30  to another blood vessel or region of the heart. As with many commercially available cannulas, the inner cannula  20  may be tubular and preferably made of flexible, biocompatible material such as silicone, and may be reinforced with other material such as steel wire to provide sufficient radial stiffness to resist collapsing. The tip  25  of the inner cannula  20  may be chamfered and relatively flexible, or not reinforced, in order to provide greater flexibility and improved advancement of the inner cannula  20  through relatively small vessels or chambers that reduces trauma to surrounding tissue. The inner cannula  20  may also have a plurality of openings  27  formed near its tip  25  to allow blood to flow into the inner cannula  20 , particularly when the distal opening  22  may become occluded or otherwise obstructed. A catheter guide wire may also be extended through the cannula openings  27  to dispose the inner cannula  20  at desired locations throughout the body including the heart region. The inner cannula  20  may be formed relatively straight or with a permanent bend having a 10 to 120 degrees curved portion to facilitate installation and removal from a blood vessel or chamber. The inner cannula  20  may also be formed of radiopaque material added or printed on its surface for visibility when exposed to X-ray radiation.  
         [0050]     As shown in  FIG. 1 , the outer conduit  30  of the fluid transport system may be formed with a distal opening  32  and a proximal opening  34 . The outer conduit may also be tubular and made of flexible, biocompatible material such as silicone, and may be reinforced with other material such as steel wire to provide sufficient radial stiffness to resist collapsing. The distal opening  32  of the outer conduit  30  may be extended through a portal  91  to form a closed circuit between the inner cannula  20  and outer conduit  30 . In a preferred embodiment, the outer conduit  30  is an introducer, or a vascular graft, such as a Dacron™ graft, or any other commercially available grafts or synthetic conduits used. The proximal end of the outer conduit  30  may be further connected to an elongated cylindrical body  40  for positioning and housing of other pump components.  
         [0051]     The device represented in  FIG. 1  may further comprise an inflow cannula  20  attached to a housing cap  60  fitted over a housing body  52 , which houses a rotor  70  coupled to a drive unit  80 . The housing cap  60  may further comprise a base member  61  and an inlet neck  62  which may be separate components joined by welding or similar techniques, or may form a unitary body. The base member  61  and the inlet neck  62  are preferably concentric to each other. Outflow windows  64  may also be positioned relatively outwardly to inlet neck  62 , and are preferably circumferential and symmetrical to inlet neck  62 . The outside diameter of the housing cap  60  is preferably matched to the inside diameter of the housing body  52  for a close tolerance fit, or any other method for attaching the housing cap  60  to the housing body  52 . The housing body  52  and the housing cap  60  may also form a unitary body. The outside diameter of the pump  50  may match the inside diameter of a graft  30  so that a hemostatic seal is maintained between the outside diameter of the housing body  52  and the inside diameter of the graft  30 . It should be noted again that the present invention may transport and control blood or any other bodily fluid.  
         [0052]     As shown in  FIG. 2 , the pump assembly of the fluid transport apparatus includes a reverse flow pump  50  with coaxially aligned or concentric inlet and outlet ports. The reverse flow pump  50  for this particular embodiment of the present invention further includes a rotor  70  axially aligned inside a cylindrical-shaped housing body  52 . The rotor  70  is connected to a drive shaft  81  which is rotated at variable rates of relatively high speed by the driving unit  80 . The distal opening of the housing body  52  of the pump  50  may be covered with a housing cap  60 . The housing cap  60  is preferably constructed of stainless steel or rigid polymer and may be formed with a plurality of outflow windows  64 . The outflow windows  64  may be radially aligned around an inlet neck  62  formed in the base member  61  of the housing cap  60 . The housing body  52  illustrated in this embodiment of the present invention is generally cylindrical-shaped and includes a longitudinally and concentrically aligned inlet tube  55 . The inlet tube  55  may be integrally attached at one end to the base plate  53  and include a centrally aligned distal opening  56 . A plurality of radially aligned cut-outs  57  may also be formed along various portions of the inlet tube  55  to permit the passage of fluid.  
         [0053]     A rotor  70  may be disposed longitudinally inside the inlet tube  55  as shown in  FIG. 2 . During operation of the fluid control apparatus in this configuration, the rotor  70  is rotated by the driving unit  80  through an opening or hole  54  in order to direct fluids such as blood from the inlet tube  55  out through the cut outs  57 . The outside diameter of the inlet tube  55  is preferably smaller than the inside diameter of the housing body  52  which creates a passageway  59  between the inlet tube  55  and the housing body  52 . A housing cap  60  is attached to the distal opening of the housing body  52 . The housing cap  60  may include a circular or disc shaped base member  61  designed to fit over the housing body  52 . A cylindrical inlet neck  62  may also be formed perpendicular to and centrally aligned to the base member  61 . The outside diameter of the inlet neck  62  is smaller than the inside diameter of both inner cannula  20  and the outer conduit  30  which forms another passageway  65  for the reverse flow of fluid such as blood. The inlet neck  62  may also be joined temporarily or permanently to the proximal opening  24  of the inner cannula  20  by bonding or welding, or may even be integrally formed. The passageway  59  and the outflow windows  64  of the housing cap  60  may be aligned with passageway  65  when the housing cap is assembled with the housing body  52 .  
         [0054]     The fluid transport apparatus  10  shown in  FIGS. 1 and 2  may further include an elongated cylindrical body  40  connected to the proximal opening  34  of the outer conduit  30 . The elongated body  40  may house both the pump  50  and the drive unit  80 . The cylindrical body  40  may be formed with various dimensions to conveniently provide further assistance in positioning the apparatus  10  in a desired location. The distal opening  22  of the inner cannula  20  and the distal opening  32  of the outer conduit  30  may be spaced apart and located in different blood vessels, for example, or on opposite sides of a heart valve so that blood may be pumped from one blood vessel or chamber to other regions of the heart. The inner cannula  20  and the outer conduit  30  may be coaxially aligned and formed with a sufficient length so that only one portal opening may be required into a major blood vessel, chamber, or any other body passageway. The lengths of the inner cannula  20  and outer conduit  30  may further be varied in accordance with particular applications such as open heart surgery, or during closed heart or other laproscopic procedures which involve forming other openings to provide percutaneous access to inner body regions.  
         [0055]     As shown in the perspective views of the reverse flow pump in  FIGS. 3 and 4 , a positioning rod  273  may be used to allow the transmission of torque or other force from positioning rod proximal end to the drive unit  80  (see  FIG. 10 ) without any significant dampening. The positioning rod  273  is preferably made from a metal or relatively stiff polymer and may comprise a central passage  275  extending the entire length of the positioning rod  273  and used for passing a guiding element  28 , such as a guide wire or a catheter or like devices, through its center. The central passage  275  of the positioning rod  273  may form a continuation of a central passage formed in the shaft of drive unit  80 , and may be used for passing electrical wire  272  or like elements to the drive unit. The central passage  275  of the positioning rod  273  is also preferably concentric with the outside diameter of positioning rod  273 . The distal portion of the positioning rod  273  may be matched to a groove  205  formed in the drive unit  80  to form a press fit, or to attach to the drive unit by welding, bonding or forming a unitary part. The proximal end of the positioning rod  273  may further comprise two handles  274  to assist in the handling of the positioning rod during placement of the pump  50 , and to prevent pushing the positioning rod  273  past the handles into a conduit. Since another variation of the present invention provides for the insertion of a left heart pump into a patient&#39;s cavity, vessel, or tissue without the use of a guide element  28 , the central passage  275  of the positioning rod  273  may therefore be removed or may simply provide for passing wires, tubes or similar accessories needed by the drive unit  80 . When a heart pump is inserted unassisted, the inner cannula  20  may simply be advanced by itself into a vessel or chamber.  
         [0056]      FIGS. 3 and 4  further illustrate silicone plugs  298  and  299  that may also be used to assist in sealing the pump, and may be formed with resilient flexible material such as silicone or like material. The outside diameter may be matched to the inside diameter of an outer conduit. Central holes  296  and  297  of the distal silicone plugs  298  and  299  are relatively concentric to their outer diameter. Grooves  294  and  295  may be formed circumferentially and midway between the proximal and distal face of the silicone plugs. Slits  292  and  293  may extend through the entire length of the silicone plugs and extend from the outside surface of the silicone plugs to the central holes  296  and  297 .  
         [0057]     As shown in FIGS.  5 A-D, the housing body  52  is preferably tubular and includes a concentric inlet tube  55 . When the housing body  52  and the inlet tube  55  are concentric and joined to a base plate  53 , a passage  59  is thereby formed for blood or other fluid to flow within. The passage  59  of the housing body  52  and the outflow windows  64  of the housing cap  60  may be aligned when the housing cap and the housing body are assembled coaxially. The inlet tube  55  may comprise multiple cut-outs  57  at its proximal end to connect the passage  59  with the inlet tube  55 . The profile of the inlet tube  55  is not necessarily cylindrical and may vary in shape to match the outside profile of the rotor  70 . Both profiles may be matched and varied according to pump design, i.e. an axial pump may have a cylindrical profile or a centrifugal pump may have an overall conical profile. A clearance between the inlet tube  55  profile and the rotor  70  should exist to permit the rotor  70  to rotate without contacting the walls of the inlet tube  55 . The inlet tube cut-outs  57  may be generally circular, and may depend on the rotor and pump category or application. The proximal end of the inlet tube  55  may be pressed into a matching groove  51  of the base plate  53 . The base plate  53  may comprise a groove  51  that is preferably concentric with the base plate  53  circumference, and a central hole  54  that is preferably concentric with the groove  51 . The outside diameter of the base plate  53  may be matched to the inside diameter of the housing body  52  to provide an interference fit to hold the base plate  53  and the housing body  52  together. The base plate  53  and the housing body  52  may be formed of a unitary part or of multiple parts joined together by known techniques such as welding, bonding, or like techniques. The housing body  52  proximal end may be attached to the distal end of drive unit  80 .  
         [0058]      FIGS. 6A and 6B  are distal side views of the reverse flow pump unit. In  FIG. 6A , the housing cap  60  is illustrated as having an inlet neck  62  and outflow windows  64 . The inner cannula  20  circumferentially surrounds the inlet neck  62  to direct fluid towards pump unit. The shape and relative number of windows  64  in the housing cap  60  may of course vary. Although shown as a substantially concentric circular configuration, the particular shape of the housing cap  60  and inlet neck  62  may also vary. The rotor  70  within the housing body  52  may be configured and rotate in a direction that would permit fluid to enter the pump through the housing windows  64  and directed away from the pump through the neck  62  of the housing cap.  FIG. 6B  illustrates yet another variation of the housing cap  60  for the pump unit, and may be selected to cooperate in particular with the operation of a hubless rotor (shown in  FIG. 8 ) for the reverse flow pump. Although the housing cap windows  64  are shown to be circumferentially surrounded by a centrally located housing cap neck opening  62 , the spacing, position and geometry of these passageways may be varied. The housing cap neck opening  62  may also vary in size and accommodate various inner cannula diameters.  
         [0059]     FIGS.  7 A-C and  8  illustrate various configurations of a rotor  70  that may be used in a reverse flow pump or any other type of fluid transport apparatus.  
         [0060]     As shown in FIGS.  7 A-C, the rotor  70  may comprise a single or multiple blades  72  extending from a longitudinally aligned central hub  74 . The blades  72  of the rotor  70  assist in directing and controlling fluid direction. Accordingly, the reverse flow pump may generate flow rates of up to 8 or 9 liters per minute depending upon the particular pump dimensions and configuration, and is fully capable of supporting circulatory functions of the heart.  
         [0061]     The rotor  70  is preferably an axial or a centrifugal hydraulic rotor, and profiled to provide lift to surrounding fluid when the rotor is rotated. As shown in  FIG. 7C , a central rotor passage  73  may extend the entire length of the rotor  70  and preferably forms a continuation of central passage  82  of drive unit  80 . The central rotor passage  73  of the rotor  70  may be left open or closed at the distal end of passage  73  with a gland valve  77  or similar closure entities to help keep blood or fluid outside of the passage. The disclosed gland valve  77  is presented as an example and is not meant to be the only method that may be used in keeping the fluid outside of passage  73  of the rotor  70 . Gland valve  77  may be made from a flexible and resilient material such as silicone. The gland valve  77  may further comprise a central conical opening  75  with a diameter of 0.040 inches at the proximal end of the valve gland and a slit  71  at the distal end of the gland valve. The slit  71  may allow the passage of commercially available guide wires or similar devices for guiding the pump to its intended placement, and may also close and provide sufficient hemostasis when the guide wire or similar devices are removed from the gland valve  77 . When no guide wire is used to position the pump assembly, the central rotor passage  73  of the rotor  70  may be removed entirely, and the gland valve  77  may be replaced with a conical or bullet shaped metallic or polymeric cap that is similar to the outside profile of the gland valve and formed without a slit  71 .  
         [0062]     In accordance with another variation of the present invention, as shown in  FIG. 8 , a hubless rotor  170  may be selected for the reverse flow pump system. The hubless rotor  170  may include a central portion  171  with an open central passageway  173  to permit the directional flow of fluid relative to the pump and an external surface with rotor blades  172  to reverse and direct the flow of fluid away from the pump. A base portion  174  and the rotor blades  172  may be selected to position and support the center portion  171  of the hubless rotor  170 . The base portion  174  may be disc shaped and may include a shaft  176  that is directly or indirectly connected to a rotor drive unit. Although the blades  172  of the illustrated embodiment also support the center portion  171 , it is understood that the supporting members may also be separately formed from the blades. The central portion  171  of the hubless rotor may be generally formed with a cylindrical geometry or other suitable configurations to permit the directional flow of fluid through the center region of the hubless rotor  170  and the reverse flow of fluid along the relatively outer region of the rotor. The particular rotor blades  172  shown in  FIG. 8  are generally formed in spiral or helical pattern, but may similarly have other configurations to effectively direct fluid to enter and exit the pump.  
         [0063]     FIGS.  9 A-E illustrate several simplified cross sections of various embodiments of the present invention. Each of the illustrated reverse flow pumps essentially consist of an outer pump housing and a rotor. The pump further consists of an inlet passageway and a separate outlet passageway to direct the flow of fluid as indicated by the arrows included in the figures for purposes of illustration. However, the direction of fluid flow may be reversed by changing the direction of the rotor movement or by varying the rotor blade configuration. In  FIGS. 9A and 9B , an additional interior compartment  160  is included within the outer pump housing walls  152 . The interior compartment  160  may be formed with inner walls  162  or  164  that surround at least a portion of the rotor  70 . The inner walls  162 / 164  and the outer walls  152  define an inner region between the rotor  70  and the inner walls  162 / 164  forming a first passageway coaxial with the inner walls. A second passageway coaxial with the outer walls  152  is defined by an outer region between the outer walls  152  and the inner walls  162 / 164 . The first passageway permits fluid flow in a first direction and the second passageway desirably permits fluid flow in the reverse direction. The interior compartment  160  may alternately be described as an inlet tube when fluid is drawn into the pump  50  within this region before being expelled through the region defined by the outer pump housing  152  and the interior compartment. Although the inlet compartment  160  and the pump housing  152  shown throughout FIGS.  9 A-E in section are preferably cylindrical, they may of course be altered accordingly for different applications.  
         [0064]     The reverse flow pump shown in  FIG. 9A  may be described as an axial flow pump in view of the generally axial direction of the fluid flow relative to the shaft  76  of the rotor. In this particular embodiment of the present invention, the walls  162  of the interior compartment  160  extend circumferentially around the rotor  70  to direct the fluid in an axial direction towards the base  154  of the pump housing  152  before being directed away from the pump  50  in the region defined by the interior compartment  160  and the outer pump housing  152 . In  FIG. 9B , the reverse flow pump shown may be described as a centrifugal flow pump in accordance with the general outwardly direction of the fluid flow relative to the shaft  76  of the rotor  70 . In this particular embodiment of the present invention, the walls  164  of the interior compartment  160  extend around a portion of the rotor  70  to direct the fluid in a general direction towards the housing walls  156  of the pump housing  152  before being directed away from the pump  50  in the region defined by the interior compartment  160  and the outer pump housing  152 .  
         [0065]      FIG. 9C  illustrates another variation of the present invention that includes a reverse flow pump  150  with a hubless rotor  170 . The hubless rotor  170  basically consists of a central portion  171  that is positioned within the pump housing  152  by supporting members and a rotor base plate  174 . The rotor  170  may also be formed with a tapered opening  178  corresponding to a tapered opening  153  formed in the housing cap  60  to form a relatively close fit. The hubless rotor  170  of the reverse flow pump tends to draw fluid entering the pump away from the unit so as to reduce the direct impact of the fluid against housing walls or the base of the pump. In this manner, a reverse flow pump with a hubless rotor may be characterized as both an axial and a centrifugal flow pump that embodies characteristics of each configuration. A relative degree of improved efficiency has been observed with the hubless rotor configuration shown in  FIG. 9C  as compared to the rotor designs illustrated in  FIGS. 9A and 9B . Satisfactory flow rates are achieved nonetheless with these and other rotor configurations for the present reverse flow pump.  
         [0066]     The various rotor designs that may be used in accordance with the principles of the present invention include rotors having central passageways with externally formed blades, internally formed blades, or with no blade portion at all. For example, in  FIG. 9D , a hubless rotor is shown with external blades in partial conical form. The periphery of the rotor  170  in this variation generally conforms to the inner surfaces of the pump housing  152  while still permitting the passage of fluid around the outer surface of the rotor. At the same time, a hubless rotor  170  may also have blades formed internally within the central portion  171  (not shown), or with no rotor blades as shown in  FIG. 9E  which may be referred to as a shear pump design. The reverse flow pump  150  and rotor assemblies shown in FIGS.  9 C-E generally permit fluid to travel through the center of the rotor  170  ordinarily occupied by a central hub. The open passageway  173  formed in the central portion  171  of the hubless rotor  170  permits fluid to be drawn into the reverse flow pump  150  and subsequently directed away from the pump. As indicated by the directional arrows drawn in FIGS.  9 C-E, the open passageway  173  may be aligned with the inlet passageway  158  of the pump housing  152 , and the region external of the central portion  171  of the hubless rotor  170  may be aligned with the outlet passageway  159  of the pump  150 .  
         [0067]      FIG. 10  illustrates a drive unit  80  that may be used in accordance with the present fluid control and delivery system. The drive unit  80  may be a miniature electric motor with an outside diameter equal to or less than the outside diameter of a housing body. The drive unit  80  may also be a pneumatic driven turbine that is used to transform energy from a pressurized source to a rotary motion of shaft  81  or any other device that could impart rotation. The proximal face of the drive unit  80  may comprise a groove  205  for attachment to the distal end of a positioning rod  273  (shown in  FIGS. 3 and 4 ). A central passage  82  with a diameter of approximately 0.040 inches may also extend through the entire length of the shaft  81 . The shaft  81  may be coupled directly or indirectly to a rotor and transmit any shaft rotation to rotor rotation. A blood seal  84  may be attached to the drive unit  80  and may comprise a central cavity  83  containing a biocompatible lubricating fluid, such as nutrilipid, dextrose solution, glycerin, or alike. The blood seal  84  may further comprise two thin lips  88  that engage the outside diameter of shaft  81  to form a closed chamber to retain the lubricating fluid inside the central cavity  83  during the pump operation. Alternate blood seal designs well known in the art may also be used in the drive unit  80 . A 40% dextrose solution may also be used as a lubricating fluid with a continuous infusion of dextrose into the seal area. When the selected drive unit is electrical, as shown in  FIG. 10 , an electric stator  89 , a magnetic rotor  90  and two bearings  78 , may be used in a conventional method to transform electric energy into rotational motion. Furthermore, when the pump or fluid transport apparatus is positioned without the use of a guide element, such as guide wire, catheters and like devices, the central passage  82  formed in the shaft  81  of the drive unit  80  may be removed or used for functions other than a passage for a guiding element.  
         [0068]     As shown in  FIG. 11 , the installment of fluid transport apparatus often includes the anastomosis of the distal end of the outer conduit  30  to the sides of a targeted blood vessel or chamber using thoracoscopic suturing, or microstapling. Prior to suturing the outer conduit  30  to a blood vessel or cavity wall, the vessel or wall portion may be isolated by using a C-clamp, thoracoscopic clamps, or any other type of similar clamp  300  that is capable of assisting in forming small ports into the body of a patient, and preferably capable of isolating only a section of the wall without complete occlusion of the vessel.  
         [0069]     After a portal  91  is created in the desired blood vessel or body cavity, as shown in  FIGS. 11 and 12 , the outer conduit  30  is inserted into the portal. A suture may be used to secure the outer conduit  30  in place relative to the portal  91 . A commercially available high stiffness guide wire  28  may also be passed through the outer conduit  30  to assist in the placement of the inner cannula  20 . The outer conduit or graft  30  may also be of sufficient length to accommodate the pump  50  from the distal end of cannula  20  to the proximal end of the positioning rod  273 . Alternatively, the pump may be positioned externally relative to the outer conduit (as shown in  FIG. 13 ). After placing the pump  50  in the outer conduit  30 , the outer conduit may be filled with saline solution, and the pump may also be primed, if desired, to substantially remove the presence of air from the pump and the outer conduit. The driving unit  80  may then be installed in a proximal position relative to the pump  50 . A proximal silicone plug  298  may be mounted on the positioning rod  273  and advanced to seal the outer conduit  30  and the driving unit  80 . A suture may be tied on the outside of the outer conduit  30 , and in the area of the graft overlaying proximal groove  295  of the proximal silicone plug  298  to secure the plug to the proximal part of the conduit. After the installation of the fluid transport apparatus  10 , the C-clamp is released gradually, and homeostasis at potential bleeding sites are visually examined unassisted or with the aid of a viewing scope. Upon achieving acceptable homeostasis or stability, the C-clamp  300  may be completely released but should be kept in ready position to clamp the anastomosis site in case of an emergency. A guide wire  28  may be also advanced with the help of imaging techniques to dispose the distal end of the inner cannula  20  in the desired blood vessel, heart chamber or other body cavity. The guide wire  28  may be inserted and positioned to a desired location before being passed through an opening or orifice formed on the distal end of the inner cannula  20 . As a result, the distal end of the inner cannula  20  may be guided to a location before removing the guide wire  28 . While positioning the distal end of the inner cannula  20 , the pump  50  may need to be advanced in the outlet conduit  30  by pushing the positioning rod  273  into the outer conduit or graft. When pump  50  reaches the desired position, the distal silicone plug  299  may be advanced to the proximal side of the drive unit  80  and secured in place by a suture, a laproscopic clamping device, or other similar techniques. A suture or a laproscopic clamping device may be employed to hold the apparatus in position or the outside diameter of the housing body  52  may also be secured to the outer conduit or graft  30  using similar techniques to secure the distal plug  299 . After securing the pump  50  to the graft, the guide wire  28  may be removed before the pump is activated. Alternatively, the guide wire  28  may be removed immediately after positioning the inner cannula  20  relative to the outer conduit  30 . The pump  50  may then be secured to the proximal ends of the inner cannula  20  and the outer conduit  30 . Accommodations for passage of the guide wire  28  through other components of the fluid transport apparatus may thus be avoided.  
         [0070]     After the pump  50  is activated, medication or drugs for slowing or completely stopping the heart may be administered when used to support cardiac functions. The pumping rate of the pump  50  may be adjusted to maintain sufficient circulation or to accommodate changes in circulatory demand. The pump  50  may also be equipped with sensing devices (not shown) for measuring various body conditions such as the blood pressure, the presence of blood, or other parameters that would suggest the need for altering the flow rate of the fluid transport apparatus  10 . For example, the apparatus may include pressure sensors along the inner cannula  20  so that a preset pressure change would signal the need to change the pumping capacity of apparatus. The pump  50  may include sensors to sense the pressure at the distal end of the cannula  20  so that a preset pressure change could signal the need to change the pumping capacity of pump. When the pressure at the distal end of inner cannula  20  decreases by a certain increment, which indicates the commencement of pump suction, a controller used with the apparatus  10  may provide warning signals or automatically decrease the flow rate of the apparatus until returning to a preset pressure at the inner cannula.  
         [0071]     In the removal of the fluid transport apparatus, the suture or laproscopic clamping device for the apparatus is first disconnected enabling it to be moved. The silicone plugs  298  and  299  and housing body  52  are freed and removed. The pump  50  is then retracted through the outer conduit  30 , and the C-clamp  300  is engaged and clamped to isolate the portal site. The anastomosis may be restored using common thoracoscopic techniques for suturing or stapling before being removed. Finally, the surgical site is closed using known surgical techniques.  
         [0072]     When the present fluid support apparatus is selected for circulatory support of the heart, a method for effectively transporting blood between regions of the heart may basically include: selecting a blood flow support apparatus  10  including a coaxially aligned inner cannula  20  and an outer conduit  30 , a coaxially aligned reverse flow pump  50  disposed therebetween; forming a portal  91  in a blood vessel in communication with the heart; connecting the outer conduit through the portal; inserting the inner cannula through the outer conduit and the portal so that the distal opening  22  of the inner cannula is disposed on opposite sides of a desired heart valve or region relative to the distal opening  32  of the outer conduit, and activating the reverse flow pump so that blood adjacent to the distal opening of the inner cannula is pumped through the inner cannula to the outer conduit.  
         [0073]     As shown in  FIG. 12 , a guide wire  28  may be advanced with the help of imaging techniques to any of the heart chambers or vessels In preparation for insertion of a fluid transport system into a patient, a commercially available high stiffness guide wire  28  may be used and passed through the central passage of the positioning rod  273  proximal end, to the distal end of the rotor  70 , passing through the gland valve  77 , and through the cannula  20 . The pump  50  and the guide wire  28  may be are inserted into a graft or outer conduit  30  and advanced to the clamped section of a vessel.  
         [0074]     In another embodiment of the present invention shown in  FIG. 13 , the pump  50  maybe sealed and attached to the outer conduit  30  with an external drive unit  80 . This variation includes the use of a pump  50  that is kept outside the skin of a patient  94  wherein the pump attaches to the proximal end of graft  30 . The outer conduit or graft  30  is anastomosed as described above, but the pump  50  is not inserted into the inside diameter of this outer conduit. Rather, only the distal end of the main outflow housing  52  is inserted into the outer conduit  30  and secured by using a suture tied around the outside diameter in the area overlapping the outer conduit. The pump  50  outflow discharges from outflow windows  64  into the inside diameter of outflow housing  52 . An advantage offered by this embodiment of the present invention is the use of a pump  50  that is kept outside the skin  94 . This variation effectively avoids the requirement for both the pump housing body  52  outside diameter and the outside diameter of the drive unit  80  to be smaller than the inside diameter of the outer conduit  30 . The outside diameter of the pump rotor and all internal parts dimensions may therefore be larger than described earlier, which may simplify the pump designs, and may enable the device capacity to be increased significantly without increase in pump design sophistication. As with other embodiments of the present invention, this variation may obviously be used with patients that already have their body open for a surgical procedure wherein graft  30  is not passed through the skin to access a vessel, heart, cavity, or any other body region.  
         [0075]      FIG. 14  is an illustration of another cardiac support apparatus  10  that may be used in accordance with the concepts of the present invention. The illustrated fluid transport apparatus  10  provides cardiac support to the right side of the heart by pumping blood from the right ventricle  97  to the pulmonary artery  98 . In this instance, a portal  91  is formed in the pulmonary artery  98  through which the distal end of the outer conduit  30  is extended. The inner cannula  20  may be inserted into the portal  91  and through the pulmonic valve  95  to reach the right ventricle  97 . Both the inner cannula  20  and the outer conduit  30  may of course be connected to a reverse flow pump, and may be further selected of appropriate lengths to facilitate endoscopic procedures or to provide on-site cardiac support which minimizes exposure of circulated blood with foreign surfaces.  
         [0076]      FIG. 15  is an illustration of another variation of a cardiac support apparatus  10  adapted particularly for left heart assistance. An outer conduit  30  is attached to a portal  91  formed in the aorta  92 , and an inner cannula  20  is continuously extended through the portal  91 , the aortic and mitral valves  96 ,  99 , respectively, and eventually the left atrium  93 . An optional balloon  85  may also be disposed on the outside surface of the inner cannula  20  to seal, or to deliver a cool fluid or mediation to the adjacent tissue. The balloon  85  may be disposed around the inner cannula  20  and connected to a conduit  86  through which air, or a suitable coolant, or mediation may be transported to the balloon  85 . When the balloon  85  is used to deliver medication, a plurality of perforations  87  may be formed on the surface of the balloon  85  to allow medication to be delivered to the surrounding tissue. The inflatable balloon  85  may also create a separation in a body cavity to provide for the transport of fluid between the regions surrounding the distal end of the inner cannula  20  and the distal end of the outer conduit  30 . In this configuration, the inner cannula  20  does not necessarily pass through body compartments separated by valves or other separating body members. For example, the inflatable balloon  85  may isolate an organ such as a kidney or seal a region of the body when pressurized within a body cavity or vessel. Fluid may be delivered under pressure from the inner cannula  20  to the region surrounding the outer conduit  30 . Accordingly, the inflatable balloon  85  may be used alone or in conjunction with other variations of the present fluid transport and control system.  
         [0077]     Another variation of the present invention is the insertion of a heart pump into the left heart side and simultaneously inserting a second heart pump into the right heart side of the patient as shown in  FIG. 16 . An inner cannula  20  may be placed in the left atrium and the second cannula  120  in the right ventricle. The inflow cannula tip  25  of cannula  20  placed in the left heart side may be advanced and placed in the left ventricle, left atrium, or any of the left heart vessels. Meanwhile, the inflow cannula tip  125  of the second cannula  120  may be placed in the right heart side and advanced into position in the right ventricle, right atrium, or any of the right heart vessels. Whether the heart pumps of the present invention operate in unison, or singularly, the circulatory functions of the heart may be supported in open or closed heart surgery without necessarily immobilizing or arresting the heart which would further require extensive surgical procedures and apparatus.  
         [0078]      FIG. 17  illustrates another variation of the present invention involving the insertion of a left heart pump into the left side of the heart, and simultaneously inserting a second heart pump into the right side of the heart. A cannula  20  may be placed in the left atrium and a second cannula  120  from another pump may be placed in the pulmonary artery and passed through the vena cava, right atrium, and right ventricle. The heart pumps shown are similar except that cannula  20  of the left heart pump may function as inflow cannula while cannula  120  of the second pump may function as an outflow cannula as earlier described. An outer conduit  30  when used with left heart pump may function as an outflow cannula while the outer conduit when used with the second pump may function as an inflow cannula. As discussed above, the second cannula  120  may have all of characteristics and capabilities of the first cannula  20 .  
         [0079]     Another variation of the present invention is the insertion of a left heart pump into the left heart side, and simultaneously inserting a second heart pump into the right heart side of the patient as shown in  FIG. 18 . The cannula  20  in this embodiment may comprise a distal balloon  185  for occluding the mitral valve, and a proximal balloon  186  for occluding the ascending aorta below the anastomosis site, and an orifice  187  for injection or suction of a fluid. Another cannula  120  from a second pump may also comprise a distal balloon  183  for occluding the pulmonic valve. However, as explained above, the second inner cannula  120  in this variation of the present invention serves as an outflow conduit while the outer conduit  130  serves as an inflow conduit. Another alternative provides for the occlusion of the mitral valve and the pulmonic valve of the patient, but not the occlusion of the ascending aorta. By operating both pumps, the heart may be partially or completely unloaded, and arrested by infusing drugs into the heart itself through the fluid orifice  187 . As a result, this procedure provides a minimally invasive and less traumatic technique to maintain heart functions, and may be particularly suitable for endoscopic applications.  
         [0080]      FIG. 19  illustrates another variation of the present invention which includes a cannula  20  extending through an outer conduit  30 . The cannula  20  of the pump may also be formed with multiple balloons on the outside diameter of cannula  20  that may be inflated through separate or common ports located outside the patient&#39;s body with air or fluid. A balloon  186  that may be formed at any position along cannula  20  may be inflated through a port and passageway  194  located outside of the patient&#39;s body with air or fluid to force a heart cavity to stretch. The balloon  186  may also be inflated to occlude a vessel, a cavity, a heart chamber, or a wound in any tissue or organ, or it may be filled with air or fluid of a lower or higher temperature than the surrounding tissue to cool or to heat a vessel, a cavity, a heart chamber, or a wound in any tissue or organ. The balloon  186  may also be inflated to hold a heart valve open, to hold a flap open, or to hold any internal structure in a desired position. Another balloon  190  may also be inflated through a port and passageway  196  located outside the patient body with air or fluid and force this second balloon  190  against the wall of a vessel, a cavity, a heart chamber, or a wound in any tissue or organ. This balloon  190  may further include a surrounding balloon  192  that may be perforated and used to inject drugs, cardioplegia solutions to arrest the heart, or any other therapeutic agent through the balloon perforations to treat, affect or alter the tissue in contact with balloon. The surrounding balloon  192  may similarly be inflated through a common port with its adjoining balloon  190 , or a separate port and passageway  198  located outside the patient body with a variety of drugs or therapeutic agents. The ports and passageways of all the aforementioned balloons may be formed adjoining to or concentric with the cannula  20 . An orifice  187  may also be formed in the cannula  20  and located between two balloons to serve as an inflow port in conjunction with the cannula tip  25 , or when the cannula tip may become occluded. The orifice  187  may also be positioned anywhere along cannula  20  surfaces. The orifice  187  may alternatively be used as an injection port, a port for measuring pressure in areas proximal to the orifice or a suction port that could be accessed from a port located outside of the patient&#39;s body. The orifice  187  and the inner lumen of cannula  20  may of course be separated, and may not affect each other and their respective functions.  
         [0081]     Another aspect of the present invention includes stabilization apparatus and related methods for providing relatively stable surgical sites as shown in  FIG. 20 . The stabilization system  410  may basically comprise a stabilization cannula  411  with an inner passageway  414  for fluid transport that is formed of a reinforced wire  418  with a proximal end  413  and a distal end  415 , an inflation lumen  412 , and an inflatable stabilization balloon  440  attached to the outer surface of the cannula. The stabilization balloon  440  may also be shifted relative to the stabilization cannula to allow the stabilization of different areas of the heart, and may be formed of two different devices, and not integral formed as one device, that are designed to work together to achieve the described function above. The balloon  440  may be formed of permeable material that will allow diffusion of a fluid that may also be used to inflate the balloon towards the outside surface of the balloon. The fluid may also contain a number of drugs used to affect the area in direct contact with the balloon  440  or be used to control the temperature of tissue in the proximity of the balloon. The stabilization cannula  411  is preferably made from a thin wall elastomeric material, such as silicone or urethane, and may include encapsulated wire material  418  to provide some degree of kink resistance. The inflation lumen  412  may be a tubular section connecting an open proximal end  417  with a miniature side opening  416 , and a blocked distal end  419 . The distal end  419  may be blocked by adhesive or alike methods to contain any fluid in inflation lumen  412  from leaking out. The inflation lumen  412  may be in communication with the balloon interior  442  via a small side opening  416  in inflation lumen  412 . The inflation lumen  412  may be in communication with the outside of the body through one of the catheter lumens  422 . The injection of any fluid at the proximal end  417  or through catheter lumen  422  assists in the inflation of inflatable balloon  440 .  
         [0082]     The stabilization apparatus  410  and a pump  420  may be introduced into the body as shown in  FIG. 21  through the femoral artery  430  with a catheter  428  linking the device to the exterior of the body. The catheter  428  may be a multilumen catheter with separate lumens to drive the pump  420 , to measure pressure in the vicinity of the catheter along its entire length, to deliver or remove fluid, to enable the passage of small diameter guides or leads, or to perform other similar functions. Other lumens may be included in the catheter  428  to measure pressure, deliver or aspire fluid, for guide wire or tools passage, or usage of a catheter lumen. The stabilization cannula  411  further includes a distal end  415  and a stabilization balloon  440  with an interior  442 . The distal end  419  of the inflation lumen  412  may be blocked and have an opening to inflate the balloon interior  442 . The external surface of the heart  446  may be stabilized, as shown in  FIG. 22 , by using commercially available tools  447  (such as CTSI Stabilizer) that may be forked to hold a specific section of the heart from moving outwardly. Meanwhile, the stabilization cannula  411  may be positioned within a ventricle or atrium. After proper positioning, a pump may be activated and take over the left ventricle function. The balloon  440  may be inflated until the ventricle wall is restrained from inward movement. The heart wall therefore becomes relatively fixed and reduces any significant movement in order to allow the surgeon to perform delicate procedures such as suturing a still vessel. The balloon  440  may also be inflated so as to not entirely occlude the area it occupies in order to allow blood or other liquids to flow around the balloon. The stabilization cannula  411  and balloon  440  may also be positioned in an atrium instead of a ventricle to fixate the heart wall at the atrium level instead of the ventricle level. The right side of the heart may be accessed through the femoral vein, the neck or arm arteries, through direct insertion into the right atrium or right ventricle, through the pulmonary artery, or any vein of the adequate size. Alternatively, a mechanical structure may be employed instead of a balloon  440  to achieve the same stabilization described above. For example, any mechanical fixation may be used including hinged arms that have low profile during insertion, and may expand when advanced to the right position to provide support from the interior surfaces. Similarly, this stabilization apparatus  410  may further be used to hold the inside wall of an organ or a cavity such as the abdominal wall or hepatic conduits during surgery.  
         [0083]      FIGS. 23 and 24  illustrate two different embodiments of the present invention. As shown in  FIG. 23 , the placement of stabilization apparatus  410  may be achieved by introducing the stabilization system alone, or with a pump  420 , through the femoral artery  430  via direct aortic insertion, or through any other artery of adequate size, i.e., brachiocephalic, carotid, etc. The proximal end  413  or the distal end  415  of the stabilization system  410  may be adapted to receive a blood pump  420  to aid in moving fluid between both ends of the conduit. The blood pump is preferably mounted to the distal end  415  of the stabilization cannula  411 .  
         [0084]      FIG. 24  similarly illustrates positioning of another stabilization system formed in accordance with the present invention. An access conduit  433  such as a Dacron™ graft may be formed to receive an extracorporeal pump  421 , or a reverse flow pump such as those described above, at the proximal end of the access conduit  433  and use the stabilization apparatus  410  for its inflow, and access conduit  433  for its outflow to result in a similar arrangement to the one described above and presented in  FIG. 24 . As explained above, the placement of the access conduit  433  may be achieved by common surgical methods used to graft a end-to-side graft. The stabilization systems shown in  FIGS. 23 and 24  illustrate only some of the various types of commercially available intravascular and extracorporeal pumps that are compatible or provided for by the present invention.  
         [0085]     Another aspect of the present invention includes a dual lumen system  210  that may be used with commonly available pumps as illustrated in  FIGS. 25-28 . These systems may include an inner cannula  220 , an outer conduit  230 , and an external pump source  250  with inlet and outlet passageways. The outer conduit  230  may be formed with a proximal opening  234  and a distal opening  232 , and an additional sealed opening  233  for passage of the relatively inner cannula  220 . The inner cannula  220  and the outer conduit  230  may be formed of different lengths to provide for the transport of fluid between the various locations surrounding the distal openings  222  and  232  of the inner cannula and the outer conduit. Both conduits may be integrally formed or consist of separate components. The proximal ends  224  and  234  of the inner cannula and the outer conduit may also be connected directly or indirectly to a pump source  250  which may be a centrifugal, axial, or mixed flow pump, or any other type of pump having inlet and outlet portions. As previously explained, the inner cannula  220  and the outer conduit  230  may be connected to either of the inlet or outlet passageways of the pump  250  depending upon the desired directional flow of fluid.  
         [0086]     As shown in  FIGS. 25-28 , the distal opening  222  of the inner cannula  220  and the distal opening  232  of the outer conduit  230  may be spaced apart and located in different body regions. For example, these distal conduit openings  222  and  232  may be positioned in blood vessels, or on opposite sides of a heart valve, so that blood may be pumped from one blood vessel or chamber to other regions of the heart. As described above with other aspects of the present invention, the tip  225  of the inner cannula  220  may be formed with an orifice or opening  227 . The relative flow of fluid to and from the pump  250  are supported within as few as one opening into a blood vessel such as an aorta, or any other body region. A portion of the inner cannula  220  may also be coaxially aligned or positioned within a distal region of the outer conduit  230  while the proximal openings  224  and  234  of both conduits are separate and in communication with the inflow or outflow passageways of a fluid pump  250  or any variety of intermediary tubes or connectors. The lengths of the inner cannula  220  and the outer conduit  230  may be further varied for particular applications such as open heart surgery, or during closed heart or other laproscopic procedures which involve forming other openings to provide percutaneous access to inner body regions.  
         [0087]     A portion of the outer conduit in the dual lumen system  210  may be formed with a sealed opening  233  to provide for the passage of the relatively inner cannula  220 . The outer conduit  230  illustrated in  FIG. 25  may be formed of a variety of other configurations, and the sealed opening  233  may be formed in an intermediate position between the proximal  234  and distal openings  232  of the outer conduit. As illustrated in  FIGS. 26-28 , the outer conduit  230  may be formed with a Y-connector portion  236  to provide a proximal opening  234  for communication with a pump passageway, and an alternate opening  233  for passage of the relatively inner cannula  220 . The alternate opening  233  may also include a hemostasis valve or any other suitable type of valve assembly to provide a homeostatic seal for the opening. As shown in  FIG. 26 , the proximal portions  224  and  234  of the inner cannula  220  and the outer conduit  230  may be similarly connected to the inlet and outlet passageways of an axial pump  250 . In  FIGS. 27 and 28 , the dual lumen assembly  210  is also shown connected to a centrifugal pump  250  and a roller pump  250 , respectively. Other alternatives to the sealed opening  233  may also be selected to permit the passage of the inner cannula  220  through the distal region  232  of the outer conduit  230 . Although the figures illustrate a coaxial relationship between the inner cannula and the outer conduit, the inner cannula may be positioned adjacent, off-center with or anywhere within the outer conduit. Similarly, the directional flow of fluid being transported within the inner cannula and the outer conduit are relatively opposite and may vary according to their respective connection to the inlet and outlet portions of the pump. It should be further understood that the dual lumen assembly may be used in combination with other aspects of the present invention including the various fluid transport systems and related procedures described above in more detail.  
         [0088]     While the present invention has been described with reference to the aforementioned applications, this description of the preferred embodiments and methods is not meant to be construed in a limiting sense. It shall be understood that all aspects of the present invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables including the types of bodily fluids that are transported, or controlled, the relative areas in which fluid is transported, the areas of the body which are being stabilized during surgery, and the use of any combination of the embodiments of the present invention. Various modifications in form and detail of the various embodiments of the disclosed invention, as well as other variations of the present invention, will be apparent to a person skilled in the art upon reference to the present disclosure. It is therefore contemplated that the appended claims shall cover any such modifications or variations of the described embodiments as falling within the true spirit and scope of the present invention.