Patent Publication Number: US-2021178142-A1

Title: Adjustable cannulation assembly and methods thereof

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 62/948,029 filed Dec. 13, 2019 and entitled, “ADJUSTABLE CANNULATION ASSEMBLY AND METHODS THEREOF”. This application also claims priority to U.S. Provisional Patent Application No. 63/062,646 filed Aug. 7, 2020 and entitled, “ADJUSTABLE CANNULATION ASSEMBLY AND METHODS THEREOF”. This application further claims priority to U.S. Provisional Patent Application No. 63/077,388 filed Sep. 11, 2020 and entitled, “ADJUSTABLE CANNULATION ASSEMBLY AND METHODS THEREOF”. Each of the 62/948,029, 63/062,646, and 63/077,388 applications are hereby incorporated by reference in their entirety. 
    
    
     FIELD 
     The claimed invention relates to cannulation assembly for minimally invasive cardiac interventions, and more specifically to an adjustable cannulation assembly for minimally invasive cardiac interventions. 
     BACKGROUND 
     Extracorporeal membrane oxygenation (ECMO) is utilized as a temporary form of mechanical circulatory support and simultaneous gas exchange for patients with cardiogenic shock or refractory heart failure, for example. In addition to providing a patient with circulatory support, ECMO may allow time for other treatments, promote recovery, or act as a bridge to alternate, more durable mechanical solutions to address acute or chronic cardiopulmonary failure. Typical ECMO circuits include a venous or return or outflow cannula, a pump, an oxygenator, and an arterial or inflow cannula. 
     A number of approaches can be utilized with an ECMO system, including via the apex of the heart for left-sided support (VA-ECMO) and via the right or left internal jugular vein for right-sided and/or respiratory support (VV-ECMO). Various forms of peripheral ECMO may involve femoro-femoral access, internal jugular access, or internal jugular vein access with return to a graft placed on the subclavian artery. These forms of ECMO, while effective, may present issues with mobility, issues with access site infection, in particular with the femoro-femoral access, as well as issues with rendering the patient non-ambulatory during the ECMO intervention and related procedures. These issues may adversely impact the healing process. 
     Transapical cannula placement into the left ventricle (VA-ECMO) can be used for patients requiring ECMO. Transapical cannula placement into the left ventricle in the setting of VA-ECMO for refractory heart failure normally requires sternotomy or thoracotomy in a highly vulnerable patient, which carries a significant risk of bleeding. VV-ECMO with access via the right or left internal jugular vein is also used, however, these approaches do not come without significant morbidity/mortality and advances must be made to maximize clinical benefits and minimize risk. Minimally invasive approaches are under development but are typically fixed in size and designed with healthy patients in mind or for patients with more predictable anatomical features in regard to the location, size, and shape of the heart. Therefore, there is a need for cannulation systems applicable to transapical and/or internal jugular vein cannula placement for use with ECMO that are adjustable based on patient size and anatomical variations. Such a customizable, patient-centered system would further enable cannula placement while allowing patients to ambulate on ECMO and therefore improve morale, hasten recovery, reduce morbidity, and optimize patient outcomes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top-left-front perspective view of a cannulation coupler. 
         FIGS. 2A, 2B, 2C, 2D, 2E, and 2F  are front, left side, right side, rear, top, and bottom elevational views, respectively, of the cannulation coupler of  FIG. 1 . 
         FIG. 3  is an exploded view illustrating assembly of the of the cannula coupler of  FIG. 1 . 
         FIG. 4  is a cross-sectional view of a cannulation assembly utilizing the cannula coupler of  FIG. 1 . 
         FIG. 5  is a partial cross-sectional view of a heart with a cannulation assembly inserted. 
         FIG. 6  is a schematic view of a surgical setting employing the cannula coupler assembly of  FIG. 5 . 
         FIG. 7  is a top-left-front perspective view of another embodiment of a cannulation coupler suitable for use in a single cannula dual lumen adjustable cannulation assembly for minimally invasive ambulatory ECMO. 
         FIGS. 8A, 8B, 8C, 8D, 8E, and 8F  are front, left side, right side, rear, top, and bottom elevational views, respectively, of the cannulation coupler of  FIG. 7 . 
         FIGS. 9A-9C  are a series of exploded views showing assembly steps of an adjustable cannulation assembly including the cannulation coupler of  FIG. 7 . 
         FIG. 10  is an exploded view illustrating assembly of the of the cannula coupler of  FIG. 7 . 
         FIG. 11  is a schematic view of a surgical setting employing the cannula coupler assembly illustrated in  FIGS. 9A-9C . 
         FIG. 12  is a perspective view of another embodiment of a cannulation coupler suitable for use in a single cannula dual lumen adjustable cannulation assembly for minimally invasive ambulatory ECMO. 
         FIG. 13  is a top-left-front perspective view of an adjustable cannulation assembly. 
         FIG. 14  is an exploded perspective view of the adjustable cannulation assembly of  FIG. 13 . 
         FIG. 15  is a top-left-front perspective view of a pulmonary artery guidewire director for use accompanying the adjustable cannulation assembly of  FIG. 13 . 
         FIG. 16  is a top-left-front perspective view of an inner cannula for use accompanying the adjustable cannulation assembly of  FIG. 13 . 
         FIG. 17  is a top-left-front perspective view of an inner cannula obturator for use accompanying the adjustable cannulation assembly of  FIG. 13 . 
         FIGS. 18A and 18B  are top-left-front and bottom-right-rear perspective views, respectively, of the pulmonary artery guidewire introducer of the adjustable cannulation assembly of  FIG. 13 . 
         FIGS. 19A-19H and 19J-19N  are schematic illustrations of a surgical method for use of the adjustable cannulation assembly of  FIG. 13  with the additional components of  FIG. 15 ,  FIG. 16 , and  FIG. 17 . It should be noted that  FIG. 19I  was not used so as not to be confused with the number  191 . 
         FIG. 20  is a side view of the adjustable cannulation assembly of  FIG. 13  illustrating several locations along a path followed by a directed pulmonary artery guidewire through the adjustable cannulation assembly. 
         FIGS. 21A-21F  are a series of several cross-sectional views of the adjustable cannulation assembly indicated in  FIG. 20 . 
         FIGS. 22A and 22B  are side views of one embodiment of an adjustable cannulation assembly illustrating adjustment of the second lumen relative to the first lumen. 
     
    
    
     It will be appreciated that for purposes of clarity and where deemed appropriate, reference numerals have been repeated in the figures to indicate corresponding features, and that the various elements in the drawings have not necessarily been drawn to scale in order to better show the features. 
     DETAILED DESCRIPTION 
       FIG. 1  is a top-left-front perspective view of a cannulation coupler suitable for use in a single cannula dual lumen adjustable cannulation assembly for minimally invasive ambulatory VA-ECMO. The cannulation coupler  10  has a primary branch  12  with a primary opening  20  in communication with a side inflow branch  14  and an outflow branch  16 . The primary branch  12  has a primary compression cap  18  configured to hold and secure a dual lumen cannula in the cannulation coupler  10  during use. The cannulation coupler  10  also has an inflow compression cap  22  on the inflow branch  14 , which is configured to hold and secure an inflow or inner cannula. The cannulation coupler  10  may be fabricated from a number of materials suitable for surgical use including surgical steel, plastic, or other suitable materials known in the art for transferring blood or similar fluids without interacting with the fluids unfavorably. It should be noted that the diameter of the inflow branch  14  is smaller than the primary branch  12 . Other embodiments of cannulation couplers may have a larger inflow branch than the primary branch. Still other embodiments of cannulation couplers may have inflow and primary branches having substantially similar diameters. 
     In an effort to clarify terminology, various descriptions have been used to characterize or describe the flow or direction of blood from the perspective of the cannulation coupler. The inflow cannula and the inflow branch of the cannulation coupler carries arterial or oxygenated blood from the ECMO system. The outflow cannula and the outflow branch, also referred to as a drainage cannula or drainage branch, of the cannulation coupler carries venous or deoxygenated blood back to the ECMO system for the purpose of oxygenating the blood flow. A primary branch merges an inflow and outflow branch or cannula into a dual lumen coaxial configuration. Other conventions in terminology, particular in reference to reversing the order of terminology relating to flow direction may exist within the medical community, but for the purposes of this description, the terminology will be used as noted above. 
       FIGS. 2A, 2B, 2C, 2D, 2E, and 2F  are front, left side, right side, rear, top, and bottom elevational views, respectively, of the cannulation coupler of  FIG. 1 .  FIGS. 2E and 2F , in particular, illustrate the respective locations and orientations of the inflow opening  26  and the outflow opening  28  with the inflow compression cap  22  assembled and attached. 
       FIG. 3  is an exploded view illustrating assembly of the of the cannula coupler of  FIG. 1 . The body  10 B of the cannulation coupler  10  defines helical threads  36  on an outside circumference of the primary branch  12 , near the primary opening  20 . A washer  32  having a step  34  to provide a depth limiter is inserted into the primary opening  20  of the primary branch  12 . The primary compression cap  18  has helical inner threads  30  that correspond to the threads  36  on the body  10 B of the cannulation coupler  10  and flats  50  on the outer circumference of the primary compression cap  18 . The flats  50  provide a configuration for tightening of the primary compression cap  18  by mechanical tools, although the primary compression cap  18  may also be tightened by hand. The primary compression cap  18  is not fully tightened until a cannula or lumen is also inserted into the primary opening  20  once the washer  32  and primary compression cap  18  are attached to the primary branch  12 . Once fully tightened, the primary compression cap  18  and primary washer  32  provide a leakproof and hermetically sealed connection for holding an outer dual lumen cannula providing a flow pathway through the connected outer cannula. On the end of the outflow branch  16 , the outflow branch  16  defines several barbs  24 . These barbs  24  are configured to temporarily yet reliably hold an outflow tube or lumen used in an ECMO surgical assembly and apparatus. On the inflow branch  14  of the body  10 B of the cannulation coupler  10  are a set of helical threads  38 . The inner diameter of the inflow branch  14  is configured such that a sealing element such as an o-ring  40  can be inserted into the inflow branch  14  without the o-ring  40  falling into the opening of the inflow branch  14 . This may be a step or a ledge on the inner diameter of the inflow branch  14 . This feature is not shown here, but should be known to those skilled in the art. Once the o-ring  40  is in place inside the inflow opening  26  of the inflow branch  14 , an inflow washer  42  is also placed in the inflow branch  14 . The inflow washer  42  has a step  44  to limit the depth of its insertion into the inflow opening  26  of the inflow branch  14 . The inflow compression cap  22  also defines inner threads  46  on an inner circumference and several flats  48 . 
     The flats  48  on the inflow compression cap  22  provide a configuration for tightening of the inflow compression cap  22  by mechanical tools, although the inflow compression cap  22  may also be tightened by hand. The inflow compression cap  22  is not fully tightened until a cannula or lumen is also inserted into the inflow opening  26  once the o-ring  40 , washer  42  and the inflow compression cap  22  are attached to the inflow branch  14 . Once fully tightened, the inflow compression cap  22 , o-ring  40 , and washer  42  provide a leakproof and hermetically sealed connection for holding an inner cannula providing a flow pathway into the cannulation coupler  10 . 
       FIG. 4  is a cross-sectional view of a cannulation assembly utilizing the cannula coupler of  FIG. 1 . An outer lumen or outer cannula  52  is shown inserted into the primary opening  20  and primary branch  12  end of the cannulation coupler  10  with the washer  32  in place and the primary compression cap  18  tightened and sealed. An inner lumen or inner cannula  54  is also shown inserted into the inflow opening  26  of the cannulation coupler  10  with the o-ring  40  in place and the inflow compression cap  22  tightened and sealed. The inner cannula  54  is further inserted into the outer cannula  52  through the primary branch  12  resulting in a dual lumen configuration. This could also be characterized as a coaxial dual lumen configuration or a cannula-in-cannula or lumen-in-lumen configuration.  FIG. 4  also illustrates the inflow direction  56  of the cannulation assembly  88 , which demonstrates the pathway and flow direction of the arterial blood into the aorta carried by the inner cannula  54 . Also illustrated is the pathway and outflow direction  58  of the venous or return flow carried by the outer cannula  52  in an ECMO system. These pathways and their overall system configuration will be discussed further in regard to  FIG. 5 . 
       FIG. 5  is a partial cross-sectional view of a heart with a cannulation assembly inserted into a heart. A patient&#39;s heart  60  is shown with the distal end  88 D of the cannulation assembly  88  shown in its intended placement within the heart  60 . The distal end  88 D of the cannulation assembly  88  is inserted into an apical opening  62  in the left ventricle  64  of the heart  60 . The cannulation assembly  88  is secured to the heart  60  with several sutures  66  and supporting pledgets  68  surrounding the apical opening  62 . As inserted, the coaxial dual lumen cannula is configured such that the distal end  52 D of the outer cannula  52  is located in the left ventricle  64 . This allows the deoxygenated blood to flow in outflow direction  58  into the distal end  52 D of the outer cannula  52  back to the ECMO system for oxygenation. The distal end  52 D of the outer cannula  52  also defines several perforations  70  that further enable adequate blood flow should the distal end of the outer cannula  52  be pressed against the inner wall of the heart. The distal end  54 D of the inner cannula  54  is inserted further into the heart  60 , such that the distal end  54 D passes through an aortic valve  76  to deliver oxygenated blood from the inner cannula  54  into an aorta  74 . When inserted into the aorta  74  the inner cannula  54  is sealed relative to the left ventricle  64  by coaptation of aortic valve leaflets  78  of the aortic valve  76 . This effectively isolates the inflow of oxygenated blood from the inner cannula  54  into the aorta  74  from the outflow of deoxygenated blood from the apical opening  62  out from the left ventricle  64 . The inner cannula  54  further defines several perforations  72  at the distal end  54 D that further enable adequate blood flow should the distal end of the inner cannula  54  be otherwise obstructed. Since the coaxial dual lumen set up is further configured such that the inner cannula  54  can be slidable coaxially from a proximal direction to a distal direction, and vice versa within the outer cannula  52 , the relative position of the distal end  54 D of the inner cannula  54  can be adjustable in relation to the position of the  52 D distal end of the outer cannula  52 . This enables an adjustability not available to conventional cannulation assemblies that have fixed positions and are not coaxially oriented relative to an inner and outer lumen single cannula. This adjustability is important to accommodate variance in anatomical sizing and features that may be present across different patients. It should also be noted that while being carried in a single, dual lumen coaxial cannula, the inflow and the outflow pathways do not blend or cross contaminate. While a transapical approach is shown, other introductory methods including VA-ECMO, VV-ECMO, and others may be utilized with such an adjustable cannula assembly as described herein. 
       FIG. 6  is a schematic view of a surgical setting employing the cannula coupler assembly of  FIG. 5 .  FIG. 6  illustrates the relative positioning of a patient  86  and the cannulation assembly  88  as inserted. An inflow lumen  84  connected to the inner cannula  54  is connected to the inflow branch  14  of the cannulation coupler  10  and carries oxygenated blood from the ECMO apparatus  80  to the patient  86 . The outer portion of the outer cannula  52  brings deoxygenated blood out of the patient and into the ECMO apparatus  80  for oxygenation via an outflow lumen  82 . The cannulation coupler  10  may be secured to the patient  86  externally in order to facilitate ambulatory movement of the patient  86  while undergoing treatment. 
       FIG. 7  is a top-left-front perspective view of another embodiment of a cannulation coupler suitable for use in a single cannula dual lumen adjustable cannulation assembly for minimally invasive ambulatory ECMO. The coaxial coupler or cannulation coupler  90  has a base port section or primary branch  92  with a base port opening  104  in communication with an inflow side port  94  and an external connection end or outflow branch  114 . The primary branch  92  has a base port cap  100  configured to hold and secure a dual lumen cannula in the cannulation coupler  90  during use. The base port cap  100  has a head  102  which is configured to assist the user in fastening the base port cap  100  onto the threaded end of the primary branch  92  with the use of an adjustable wrench or similar tool. While the head  102  illustrated is a hex-type nut shape, other fastening head shapes or configurations known to those skilled in the art may also be utilized. The cannulation coupler  90  also has side cap  108  on the inflow side port  94 , which is configured to hold and secure an inflow or inner cannula to the inflow side port  94 . The side cap  108  has a head  110  which is configured to assist the user in fastening the side cap  108  onto the threaded end of the inflow side port  94  with the use of an adjustable wrench or similar tool. While the head  110  illustrated is a hex-type nut shape, other fastening head shapes or configurations known to those skilled in the art may also be utilized. The outflow branch  114  has several concentric barbs  112  defined by the outflow branch  114 . These barbs  112  are configured to secure a tube or other cannula which may be placed onto the outflow branch  114  of the cannulation coupler  90 . As this embodiment illustrates barbs  112  on the outflow branch  114 , other securing means known in the art may be used in the assembly. The cannulation coupler  90  may be fabricated from a number of materials suitable for surgical use including surgical steel, plastic, or other suitable materials known in the art for transferring blood or similar fluids without interacting with the fluids unfavorably. It should be noted that the diameter of the inflow side port  94  is smaller than the primary branch  92 . Other embodiments of cannulation couplers may have a larger inflow side port than the primary branch. Still other embodiments of cannulation couplers may have inflow side port and primary branches having substantially similar diameters or sizes. A protrusion  96  defined by the primary branch  92  further defines a retaining feature, an attachment eyelet  98  configured to secure the cannulation coupler  90  to a patient once the cannulation coupler  90  and its accompanying assembly is installed and completed. A second inflow side port retaining feature or attachment eyelet  106  is also defined by the inflow side port  94 .  FIGS. 8A, 8B, 8C, 8D, 8E, and 8F  are front, left side, right side, rear, top, and bottom elevational views, respectively, of the cannulation coupler of  FIG. 7 . 
       FIGS. 9A-9C  are a series of exploded views showing assembly steps of an adjustable cannulation assembly including the cannulation coupler of  FIG. 7 . These assembly steps are shown outside the context of patient or instrumentation use for purposes of clarity. As shown in  FIG. 9A , a first lumen  132  has been modified by cutting or otherwise removing a portion of a distal end  132 D proximal end  132 P of the first lumen  132  until approximately 2 mm from the reinforcement end is remaining on the distal end  132 D proximal end  132 P of the first lumen  132 . While not shown in this view, a portion of a distal end  132 D of the first lumen  132  may also be removed in order to facilitate subsequent steps of the assembly. This sectioning of a portion of the distal end  132 D of the first lumen  132  can be accomplished by beginning to section at or near a port hole in a distal end  132 D of a first lumen  132 , then cutting towards the distal end along a center line of the lumen. The distal end  132 D can be further flared and any excess material or sharp edges removed. Next, the bushing  116  is placed over the distal end  132 D of the first lumen  132  and moved towards the distal end  132 D proximal end  132 P of the first lumen  132  in direction  134 . The base port cap  100  is then placed over the distal end  132 D of the first lumen  132  and moved towards the distal end  132 D proximal end  132 P of the first lumen  132  in direction  134 . The distal end  132 D proximal end  132 P of the first lumen  132  and the insert  118  on the bushing  116  are then placed into the base port opening  104  of the cannulation coupler  90  such that the flange  120  of the bushing  116  is contacting the primary branch attachment cylinder  122  and the distal end  132 D proximal end  132 P of the first lumen  132  is fully seated and sealed in the base port opening  104  of the cannulation coupler  90 . The base port cap  100  is then tightened by hand or with an additional tool to fully fasten the base port cap  100  onto the cannulation coupler  90  and seal the first lumen  132  into the cannulation coupler  90 . The result of the preceding assembly steps is shown in  FIG. 9B . Next, an o-ring  130  is inserted and seated into a proximal end  94 P of inflow side port  94  of the cannulation coupler  90 . Side cap  108  is placed over a distal end  138 D of a second lumen  138  and slid towards a proximal end  138 P of the second lumen  138 . The distal end  138 D of the second lumen  138  is then inserted into the proximal end  94 P of the inflow side port  94 , through the primary branch  92  and into the distal end  132 D proximal end  132 P of the first lumen  132  towards the distal end  132 D of the first lumen  132  in direction  136 . Now the portion of the first lumen  132  protruding from the base port cap  100  of the cannulation coupler  90  has the second lumen  138  coaxially inserted throughout its length and the distal end  138 D of the second lumen  138  is protruding from the distal end  132 D of the first lumen  132 , as illustrated in  FIG. 9C .  FIG. 9C  shows the result of the preceding assembly steps. A last assembly step shows the attachment of an external lumen  140  by placing a distal end  140 D of the external lumen  140  in direction  142  over the outflow branch  114 . While this method and order of component assembly has been described in regard to  FIGS. 9A-9C , other means and orders of operation may be used in order to achieve the same structure and function of an adjustable cannulation assembly. The removing of a section from a proximal end of a first cannula, removing of a section from a distal tip of the first cannula, affixing the proximal end of the first cannula onto a main port of a cannulation coupler, inserting a distal end of a second cannula into a side port of the cannulation coupler, inserting the distal end of the second cannula into the proximal end of the first cannula such that the distal end of the second cannula protrudes from the distal end of the first cannula; and securing the second cannula into the cannulation coupler may be accomplished in alternate order of operation and fashion according to surgical team preference and/or availability of individual components. 
     An alternate means of assembly of the coaxial coupler assembly may be to first engage the drainage cannula via the base port. The o-ring is pushed within the delivery cannula side port and the delivery cannula is then inserted via the side port of the cannulation coupling device and through the delivery cannula. When the desired position of the cannula is confirmed externally, the bushing is pushed into place and threaded on the main body of the coupling device to ensure a hemostatic seal. Finally, the appropriate tubing, indicated for use with the chosen ECMO pump, is engaged with the remaining side port of the device. 
     When all the appropriate components are present and the system is completely assembled, the patient will be cannulated for ECMO via the surgeon&#39;s preferred approach based on the given patient&#39;s indication for mechanical circulatory support (MCS). This is done using standard sterile technique. This system allows for the possibility of cannulating through the apex of the heart for left-sided cardiac support (VA-ECMO) or via the internal jugular vein for right-sided cardiac and/or ventilatory support (VV-ECMO). This system allows for independent repositioning of the drainage and delivery cannulae relative to one another. Once the proper location of the cannulae is verified, mechanical circulatory support is initiated. Deoxygenated blood will be transported via a 34-Fr drainage cannula, through the cannulation coupler and assembly, and to the chosen ECMO pump for oxygenation. At this point oxygenated blood will be pumped to the delivery cannula, contained within the drainage cannula, and will transport blood to the chosen great artery. 
       FIG. 10  is an exploded view illustrating assembly of the of the cannula coupler of  FIG. 7 . The cannulation coupler  90  defines a primary branch  92 , having a primary opening  104 . A bushing  116  having a flange  120  and an insert  118  to provide a depth limiter is inserted into the primary opening  104  of the primary branch  92 . The base port cap  100  has inner threads, not shown in this view, that correspond to threads near the base port opening  104  of the cannulation coupler  90  and a head  102  having flat edges on the outer circumference of the base port cap  100 . The flats on the head  102  provide a configuration for tightening of the base port cap  100  by mechanical tools, although the base port cap  100  may also be tightened by hand. The base port cap  100  is not fully tightened until a cannula or lumen is also inserted into the base port opening  104  once the bushing  116  and base port cap  100  are attached to the primary branch  92 , as described in regard to  FIGS. 9A-9C . Once fully tightened, the base port cap  100  and bushing  116  contribute to providing a leakproof and hermetically sealed connection for holding an outer dual lumen cannula providing a flow pathway through the connected outer first cannula. On an opposite end of the primary branch  92 , the cannulation coupler  90  also defines an outflow branch  114  having several barbs  112 . These barbs  112  are configured to temporarily yet reliably hold an outflow tube or lumen used in a VA-ECMO surgical assembly. On the side port  94  of the body of the cannulation coupler  90  are a set of inner threads, not shown in this view. The inner diameter of the inflow side port  94  is configured such that an o-ring  130  can be inserted into the side port  94  without the o-ring  130  falling into the opening of the inflow side port  94 . There is a step or a ledge on the inner diameter of the side port  94 . This feature is not shown here, but should be known to those skilled in the art. Once the o-ring  130  is in place inside the inflow opening of the side port  94 , a side cap  108  having a head  110  and further defining a flange  128  and a side cap insert  126  is also placed in the side port  94 . The flange  128  on the side cap  108  limits the depth of the insertion of the side cap  108  into the inflow opening of the side port  94 . The side cap  108  also defines inner threads, which are not shown in this view, and several flats on the head  110 , which are configured in a similar manner to that of the base port cap  100 . 
       FIG. 11  is a schematic view of a surgical setting employing the cannula coupler assembly illustrated in  FIGS. 9A-9C .  FIG. 11  is a cross-sectional view of a cannulation assembly  144  utilizing the cannula coupler of  FIG. 7 . An outer first lumen  132  is shown inserted into the base port cap  100  and primary branch  92  end of the cannulation coupler  90  with the bushing  116  in place and the base port cap  100  tightened and sealed. An inner second lumen  138  is also shown inserted into the side port  94  of the cannulation coupler  90  with the o-ring  130  in place and the side cap  108  tightened and sealed. The inner second lumen  138  is further inserted into the outer first lumen  132  through the side port  94  and through the primary branch  92  and base port cap  100  in a dual lumen configuration. This could also be characterized as a coaxial dual lumen configuration or a cannula-in-cannula or lumen-in-lumen configuration.  FIG. 11  also illustrates the inflow direction  143  of the cannulation assembly  144 , which demonstrates the pathway and flow direction of the arterial blood into the aorta carried by the inner second lumen  138 . Also illustrated is the pathway and outflow direction  145  of the venous or return flow carried by the outer first lumen  132  in an ECMO system. 
     The dual lumen coaxial cannulation assembly described herein results in an adjustable cannula intended towards ambulatory ECMO with a novel coupler. The cannulation system is intended for use in a minimally invasive transapical closure system, but may be applicable elsewhere. In many ECMO related procedures, the inflow or outflow pressures may or may not be monitored during the procedures. In some cases, only the flow rate of the inflow portion of the circuit is monitored during an ECMO procedure. A flow rate of 5 liters per minute is usually adequate for VA-ECMO. A target of 4.8-5.5 liters per minute is a common target and may be modified outside the stated boundaries relative to the treatment needs of a given patient, but 5 liters per minute is an adequate target value. V-V ECMO as introduced via an inner jugular vein may require flows as high as 6-7 liters per minute utilizing two separate 25 French cannulas. Pressure and flow are commonly the measurable criteria in perfusion technology related procedures. 
     In experimentation conducted using clinical ECMO oxygenation and pumping apparatus, control for flow was established using separate cannulas of the similar ranges of sizes as experimentally used. Near equivalent flow rates and pressures were observed when comparing a common ECMO setup using a 17 French inflow cannula and a 24 French outflow cannula with the coaxial dual lumen cannula assembly as described herein. The dimensions of the coaxial dual lumen were 17 French inflow or inner cannula inserted into a 34 French outer cannula. This phenomenon can be explained by the relationship between the cross-sectional diameters of the inner and outer cannula in the slidable coaxial dual lumen cannula assembly. The inflow cannula of the separate (non-coaxial) and coaxial cannula assemblies were both 17 French, or the same size. The outflow cannula of the non-coaxial cannula assembly was 24 French, while the outflow cannula of the coaxial cannula assembly was 34 French. The 34 French with the 17 French inner cannula inserted in the coaxial assembly results in restricted internal cross-sectional area and is comparable to a similar cross-sectional area in the 24 French outflow cannula in the non-coaxial cannula assembly. While these specific numbers are provided by way of illustrating the concept, they are not meant to be limited to only these dimensions of inflow and outflow cannulas, since the requirements of the system and patient condition may warrant the use or configuration of dual lumen coaxial cannula assemblies outside of the dimensions stated here by way of example. 
       FIG. 12  is a perspective view of another embodiment of a cannulation coupler suitable for use in a single cannula dual lumen adjustable cannulation assembly for minimally invasive ambulatory ECMO. The cannulation coupler  146  has a primary branch  148  with a base port  156  in communication with a side inflow branch  150  and a drainage or external port, or outflow branch  158 , each defined by the structure of the cannulation coupler  146 . The primary branch  148  defines the base port  156  at one end which defines several concentric barbs  160  configured to securely yet releasably hold a lumen or cannula in place. The primary branch  148  also defines the outflow branch  158  at an opposite end which also defines several concentric barbs  162  also configured to securely yet releasably hold a lumen or cannula in place. The primary branch  148  also defines a base port limit  164  and an external port limit  166  at either end, configured to provide a sealing surface and consistent limitation for a lumen or cannula connected to either the base port  156  or the outflow branch  158 . The primary branch  148  of the cannulation coupler  146  also defines several retaining features  152 ,  154  which are configured to anchor and secure the cannulation coupler  146  to a patient or to other apparatus used in an ambulatory ECMO procedure and treatment. The retaining features and the act of securing the cannulation coupler  146  and associated assembly to a patient enables and allows mobility of a patient while undergoing treatment under such procedures. One retaining feature  154  is adjacent to an outer junction between the side inflow branch  150  and the primary branch  148 . On the side inflow branch  150 , the cannulation coupler  146  also has a side inflow branch cap  168  which defines a head  170 , the features of which have been previously described herein. The side inflow branch  150  further comprises helical threading, not shown in this view, on a portion of an inner circumference. As previously described herein, the side inflow branch cap  168  has an aperture or opening configured to pass through and hermetically seal there within a lumen or cannula as a part of the overall assembly. The cap  168  also has helical threads on an outer circumference that interlock with the inner threads on the side inflow branch  150 . An axis defined by the side inflow branch  150  is disposed at an angle relative to an axis defined by the primary branch  148 . While the angle illustrated in  FIG. 12  is 25 degrees, alternate angles may be used in other embodiments. An axis defined by the outflow branch  158  is parallel to an axis defined by the primary branch. Alternate angles may be utilized in other embodiments of a cannulation coupler. The cannulation coupler  146  may be fabricated from a number of materials suitable for surgical use including surgical steel, plastic, or other suitable materials known in the art for transferring blood or similar fluids without interacting with the fluids unfavorably. It should be noted that the diameter of the side inflow branch  150  is smaller than the primary branch  148 . Other embodiments of cannulation couplers may have a larger side inflow branch than the primary branch. Still other embodiments of cannulation couplers may have side inflow branch and primary branches having substantially similar diameters. 
       FIG. 13  is a top-left-front perspective view of an adjustable cannulation assembly. This embodiment of an adjustable cannulation assembly  172  includes a first IVC cannula  174  defining a first plurality of IVC perforations  188 , a second plurality of upper SVC perforations  184 , and a side port  186  in communication with an IVC cannula channel  190 . The IVC cannula channel  190  of the first IVC cannula  174  continues from a distal end  174 D of the first IVC cannula  174  to a proximal end  174 P of the first IVC cannula  174 . The side port  186  is configured such that it exits the IVC cannula channel  190  radially and is on a side of the first IVC cannula  174 . The first IVC cannula  174  is coupled to the cannulation coupler  146  at the base port  156  of the cannulation coupler  146 . On an opposite end of the cannulation coupler  146 , an eccentric obturator cap  180  is coupled to the outflow branch  158  of the cannulation coupler  146 . Inserted within the eccentric obturator cap  180  and continuing throughout the primary branch of the cannulation coupler  146 , and further through the IVC cannula channel  190  of the first IVC cannula  174  is a first IVC obturator  178 . The first IVC obturator  178  defines a knob  194  at a proximal end  178 P of the first IVC obturator  178  and an obturator channel  192  from a proximal end  178 P of the first IVC obturator  178  to a distal end  178 D of the first IVC obturator  178 . The distal end  178 D of the first IVC obturator  178  is visible protruding from the distal end  174 D of the first IVC cannula  174 . Inserted within the side inflow branch cap  168  of the side inflow branch  150  of the cannulation coupler  146  is a pulmonary artery guidewire introducer  176 . The pulmonary artery guidewire introducer  176  extends to the side port  186  of the first IVC cannula  174 , where it terminates in a guidewire introducer exit  196  defined by a distal end  176 D of the pulmonary artery guidewire introducer  176 . A proximal end  176 P of the pulmonary artery guidewire introducer  176  can be seen protruding from the side inflow branch cap  168  of the side inflow branch  150  on the cannulation coupler  146 . A pulmonary artery guidewire introducer plug  182  is fitted into the proximal end  176 P of the pulmonary artery guidewire introducer  176 . The pulmonary artery guidewire introducer  176  will be discussed in further detail later in regard to  FIGS. 18A and 18B . 
       FIG. 14  is an exploded perspective view of the adjustable cannulation assembly of  FIG. 13 . The first IVC cannula  174  is coupled at the proximal end  174 P to the base port  156  of the cannulation coupler  146 , and held fixedly in place by the several barbs on the end of the base port  156 . The o-ring  169  is placed into the side inflow branch  150  of the cannulation coupler  146 , followed by the cap  168 , which is screwed into the side inflow branch  150  over the o-ring  169 . The eccentric obturator cap  180 , of which an eccentric opening  198  is now visible, is attached to the external port  158  of the cannulation coupler  146 , and held fixedly in place by the several barbs on the end of the external port  158 . Next, the first IVC obturator  178  is inserted through the eccentric opening  198  of the eccentric obturator cap  180 , and through the first IVC cannula  174  to the proximal end  174 P of the first IVC cannula  174 . It should be noted that the off center location of the eccentric opening  198  in the eccentric obturator cap  180  orients the first IVC obturator  178  towards one side of the first IVC cannula  174 . Next, the pulmonary artery guidewire introducer  176 , which further defines a body  240  portion, a neck  200  portion, and a fitting portion  202  is inserted by placing the distal end  176 D of the pulmonary artery guidewire introducer  176  into the cap  168 , through the side inflow branch  150  of the cannulation coupler  146 , and finally into the first IVC cannula  174 , terminating with the guidewire introducer exit  196  firmly positioned within the side port  186  of the first IVC cannula  174 . Finally, the pulmonary artery guidewire introducer plug  182 , which further defines an insert  206  portion, is releasably pressed into the entrance  204  of the pulmonary artery guidewire introducer  176 . 
       FIG. 15  is a top-left-front perspective view of a pulmonary artery guidewire director for use accompanying the adjustable cannulation assembly of  FIG. 13 . A pulmonary artery guidewire director  208  defines a knob  210  at a proximal end  208 P. The knob  210  further defines a directional indicator fin  212 , which is configured to enable turning or directionally orienting a pulmonary artery guidewire when the pulmonary artery guidewire director  208  is used within a minimally invasive procedure utilizing an adjustable cannulation assembly  172  as described herein. The pulmonary artery guidewire director  208  also defines a straight portion  218  and a curved portion  216  towards a distal end  208 D of the pulmonary artery guidewire director  208 . The pulmonary artery guidewire director  208  also has an inner channel  214 , from the proximal end  208 P to the distal end  208 D of the pulmonary artery guidewire director  208  configured to guide and direct a guidewire therethrough. The pulmonary artery guidewire director  208  is comprised of a pre-curved flexible plastic material suitable for surgical use which can be introduced throughout a cannulation assembly such as the one described herein yet regain its shape upon exit of any constraint within a lumen or other delivery channel. While illustrated here as a preformed curved embodiment, alternate embodiments may be straight or otherwise shaped depending upon surgical preference, anatomical variations or other conditions, or configurations of accompanying guidewire structures or designs. The proposed use of the pulmonary artery guidewire director  208  will be described in further detail in regard to  FIGS. 19A-19H and 19J-19N . 
       FIG. 16  is a top-left-front perspective view of an inner cannula for use accompanying the adjustable cannulation assembly of  FIG. 13 . An inner cannula  220  having a proximal end  220 P and a distal end  220 D also defines an inner channel  236  passing therethrough from the proximal end  220 P to the distal end  220 D, and several distal perforations  222  at the distal end  220 D of the inner cannula  220 . Typical commercially available cannulae used with an adjustable cannulation assembly as described herein will be a singular straight lumen, but the inner cannula  220  is shown in its desired state within the adjustable cannulation assembly  172  and as related to the procedures described for use within the adjustable cannulation assembly  172 . The inner cannula  220  illustrated in  FIG. 16  is sized as a 19 Fr cannula, but the specific size, additional design features, and configuration of the inner cannula used in minimally invasive surgical procedures described herein may be dependent upon the immediate surgical considerations as well as anatomical variations of a patient or available accompanying surgical equipment. The proposed use of the inner cannula  220  will be described in further detail in regard to  FIGS. 19A-19H and 19J-19N . 
       FIG. 17  is a top-left-front perspective view of an inner cannula obturator for use accompanying the adjustable cannulation assembly of  FIG. 13 . An inner cannula obturator  226  having a proximal end  226 P and a distal end  226 D defines an inner channel  236  passing therethrough from the proximal end  226 P to the distal end  226 D of the inner cannula obturator  226 . The inner channel  236  is configured to receive a guidewire such that the inner cannula obturator  226  may be utilized to help push and direct the inner cannula  220  through the adjustable cannulation assembly  172 . The inner cannula obturator  226  also defines a // 228  at the proximal end  226 P. Alternate embodiments may have additional handle features such as a directional indicator. The inner cannula obturator  226  is illustrated as made from a pre-curved flexible plastic material suitable for surgical use that can be introduced throughout a cannulation assembly such as the one described herein, yet regain its shape upon exit of any constraint within a lumen or other delivery channel. While illustrated here as a preformed curved embodiment, alternate embodiments may be straight or otherwise shaped depending upon surgical preference, anatomical variations or other conditions, or configurations of accompanying guidewire structures or designs. The proposed use of the inner cannula obturator  226  for advancing an inner cannula through an adjustable cannulation assembly will be described in further detail in regard to  FIGS. 19A-19H and 19J-19N . 
       FIGS. 18A and 18B  are top-left-front and bottom-right-rear perspective views, respectively, of the pulmonary artery guidewire introducer of the adjustable cannulation assembly of  FIG. 13 .  FIG. 18A  illustrates the pulmonary artery guidewire introducer  176 , which defines a fitting portion  202  and a cap  242  at a distal end  176 D. The fitting portion  202  is sized and configured to fit within the cap of the cannulation coupler  146  in the adjustable cannulation assembly  172  of  FIG. 13 . Adjacent to the proximal end  176 P is a neck  200  coupled to the fitting portion  202  and a body  240  coupled to the neck  200 . Along the body  240  of the pulmonary artery guidewire introducer  176  is a second side channel  246  which begins at an aperture  244  near the junction between the neck  200  and body  240  and terminates at a side port interlock feature  248  at a distal end  176 D of the pulmonary artery guidewire introducer  176 . The side port interlock feature  248  is sized and configured to interface in a complementary fashion with the side port  186  of the first IVC cannula  174  within the adjustable cannulation assembly  172 . This feature ensures that the pulmonary artery guidewire introducer  176  is correctly positioned within the first IVC cannula  174  and that a guidewire inserted into and through the pulmonary artery guidewire introducer  176  will be reliably directed outward from the side port interlock feature  248  portion of the pulmonary artery guidewire introducer  176  and out of the side port  186  of the adjustable cannulation assembly  172 .  FIG. 18B  is a bottom-right-rear perspective view of the pulmonary artery guidewire introducer  176  and illustrates a first side channel  250  located within the neck  200  portion of the pulmonary artery guidewire introducer  176 . The pulmonary artery guidewire introducer  176  is configured to receive and direct a guidewire from the entrance  204  at the proximal end  176 P into the first side channel  250 , through the aperture  244  to the opposite side of the pulmonary artery guidewire introducer  176 , through the second side channel  246  as shown in  FIG. 18A , and out of the side port interlock feature  248  at the distal end  176 D of the pulmonary artery guidewire introducer  176 . The pulmonary artery guidewire introducer  176  is made from a flexible, surgical grade plastic or other material and may also have an enclosing tube-like structure, collar, or other similar retention feature coupled around the neck  200  to further entrain and guide a guidewire inserted throughout the pulmonary artery guidewire introducer  176  as described. The intended use of the pulmonary artery guidewire introducer  176  within the adjustable cannulation assembly  172  will be described in further detail in regard to  FIGS. 19A-19H and 19J-19N . 
       FIGS. 19A-19H and 19J-19N  are schematic illustrations of a surgical method for use of the adjustable cannulation assembly of  FIG. 13  with the additional components of  FIG. 15 ,  FIG. 16 , and  FIG. 17 . It should be noted that  FIG. 19I  was not used so as not to be confused with the number  191 . While previously described embodiments of adjustable cannulation assemblies, for example, as described in regard to  FIGS. 1-10  may have been utilized in a minimally invasive surgical procedure involving a transapical entry position, alternate minimally invasive approaches that still preserve patient mobility and ambulatory accommodation may be employed. For example, utilization of an adjustable cannulation assembly having five ports such as the embodiment illustrated in  FIG. 13  via access or entry via the right internal jugular vein (IJ) may be used based on the immediate needs of a particular patient, surgical team preference, accessory equipment availability, or combinations thereof. Preparation of a patient for use of an adjustable cannulation assembly via the right internal jugular vein (IJ) includes establishing a patient in a prone Trendelenburg position with legs elevated and head down. The skin centered over the right IJ is prepared, a standard skin incision and superficial dissection is performed, using direct pressure tamponade as needed, and ultrasound guidance is used to perform a needle puncture of the right IJ vein. Needle tip location may be confirmed using blood aspiration. While these steps are not explicitly illustrated herein, they should be well-known to one skilled in the art. As illustrated in  FIG. 19A , once a patient is prepared for a right inner jugular access ECMO cannulation procedure, an IVC guidewire  270  is placed into the inner jugular entry  254  through a superior vena cava  256  portion of a patient&#39;s heart  252 , and down through to an inferior vena cava  258 , using ultrasound guidance, and optionally, the use of a snare from the groin if necessary. Other features of the heart are illustrated herein, including their approximate relative locations, including a right atrium  260 , right ventricle  262 , tricuspid valve  263 , pulmonary valve leaflets  264 , pulmonary valve  266 , and pulmonary artery  268 . 
     To proceed with inferior vena cava cannulation, the wound site external to the patient is then serially dilated to accommodate a 30-Fr outer diameter tube. The adjustable cannulation assembly  172  is prepared for use and flushed with saline. As illustrated in  FIG. 19B , the IVC guidewire  270  is passed into the conical tip of the first IVC obturator  178  at the distal end  172 D of the adjustable cannulation assembly  172 . The adjustable cannulation assembly  172  is then advanced in direction  274  towards the inferior vena cava  258  until the lower IVC perforations  188  in the IVC cannula  174  are seen by ultrasound in the IVC. This intended position is shown in  FIG. 19C . Right ventricle cannulation is then accomplished by first removing the pulmonary artery guidewire introducer plug  182  from the pulmonary artery guidewire introducer  176  located in the side inflow branch  150  of the cannulation coupler  146 . A pulmonary artery guidewire  276  is then introduced into the entrance  204  of the pulmonary artery guidewire introducer  176  in direction  289 , as illustrated in  FIG. 19D .  FIG. 19E  shows the intended location of a j-tip  278  at a distal end of the pulmonary artery guidewire  276  as directed by the first side channel and second side channel of the pulmonary artery guidewire introducer  176 , as previously described in regard to  FIGS. 18A and 18B . The j-tip  278  of the pulmonary artery guidewire  276  exits through the side port  186  and into the right atrium  260 . Further details describing the pulmonary artery guidewire  276  pathway through the pulmonary artery guidewire introducer  176  and through the adjustable cannulation assembly  172  will be further described in regard to  FIG. 20  and  FIGS. 21A-21F . At this point the rotational position should be established and confirmed, such that the side inflow branch  150  of the cannulation coupler  146  is directed away from the patient&#39;s chin and neck. The pulmonary artery guidewire  276  may be advanced and retracted to aim the j-tip  278  towards the tricuspid valve  263 . The j-tip  278  is then advanced through the tricuspid valve  263  and into the right ventricle  262 . Once the pulmonary artery guidewire  276  is in position in the right ventricle  262  as illustrated in  FIG. 19E , the IVC obturator  178  and the IVC guidewire  270  are removed from the external port  158  of the cannulation coupler  146  by retracting in direction  290 , as illustrated in  FIG. 19F . Next, as shown in  FIG. 19G , an ECMO drainage tube  292  is attached to the external port  158  of the cannulation coupler  146  and secured as needed.  FIG. 19H  illustrates the removal of the pulmonary artery guidewire introducer  176  via direction  294  and removing the pulmonary artery guidewire  276  from the internal channels of the pulmonary artery guidewire introducer  176 , leaving the j-tip  278  of the pulmonary artery guidewire  276  in the right ventricle  262 . 
     Cannulation of the pulmonary artery is then accomplished by advancing the flexible preformed pulmonary artery guidewire director  208  over the pulmonary artery guidewire  276  and into the side inflow branch  150  of the cannulation coupler  146  until the radiopaque distal end exits the side port  186  and enters the right ventricle  262 . Alternatively, a steerable or pre-angled guidewire may be used in place of the pulmonary artery guidewire director  208 . The pulmonary artery guidewire director  208  is manipulated, along with its indwelling pulmonary artery guidewire  276 , by use of the directional indicator fin  212  to pass the pulmonary artery guidewire  276  distal to the pulmonic valve  262 . Alternatively, if indicated, this pulmonary artery guidewire  276  may be replaced with a larger caliber, more rigid, or otherwise configured guidewire. The final placement of this pulmonary artery guidewire director  208  and location of the pulmonary artery guidewire  276  are illustrated in  FIG. 19J . Once the j-tip  278  of the pulmonary artery guidewire  276  is in either the left or right branch of the pulmonary artery  268  the pulmonary artery guidewire director  208  is removed. The pulmonary artery guidewire director  208  is shown removed and the j-tip  278  of the pulmonary artery guidewire  276  is located in the pulmonary artery  268  in  FIG. 19K . A flushed inner delivery cannula  220  with the in-place inner cannula obturator  226  over the pulmonary artery guidewire  276  is advanced through the side inflow branch  150  in the cannulation coupler  146  as shown in  FIG. 19L , and through the adjustable cannulation assembly  172  until exiting the side port  186  as shown in  FIG. 19M . While a 19-Fr inner cannula is shown in use, other sizes or configurations may be used as dictated by surgical preference or patient anatomy. The inner cannula  220  is advanced over the pulmonary artery guidewire  276  until all of the distal perforations  222  are distal to the coapted pulmonary valve leaflets in the pulmonary valve  266 . Achieving this may depend on elements described herein having varying dimensions, additional tools, or complimentary techniques not described herein, but known to those skilled in the art, and may depend on patient anatomy or other considerations. The inner cannula obturator  226  and the pulmonary artery guidewire  276  are then removed from the adjustable cannulation assembly  172  via the side inflow branch  150  of the cannulation coupler  146  as illustrated in  FIG. 19N . Once in this configuration, an inflow ECMO tube is attached or coupled to the inner cannula  220  and secured as needed. The adjustable cannulation assembly  172  is now vented and air-free flow is established, the optimal locations of the lower IVC perforations  188  and upper SVC perforations  184  in the IVC cannula  174  are reconfirmed, and the cannulation coupler  146  is secured to the skin near the initial puncture site to establish relative location of the adjustable cannulation assembly  172 . Supra-valvular positioning of all distal perforations  222  in the inner delivery cannula  220  and appropriate flow rates and pressures are reconfirmed. The ECMO circuit has now been established. A wrench or other suitable tool is then used to tighten and lock the nut cap on the cannulation coupler  146 . Finally, the procedure concludes with confirmation of cannula position flows and pressures, taping exposed assembly connections to further cover and secure components outside of the patient&#39;s body, and dressing the wound site. 
       FIG. 20  is a side view of the adjustable cannulation assembly of  FIG. 13  illustrating several locations along a path followed by a directed pulmonary artery guidewire through the adjustable cannulation assembly.  FIGS. 21A-21F  are a series of several cross-sectional views of the adjustable cannulation assembly indicated in  FIG. 20 . The cross-sections follow the path of the pulmonary artery guidewire from the side inflow branch  150  of the cannulation coupler  146  down through the IVC cannula  174  and out of the side port  186  of the IVC cannula  174 . While procedurally, the elements shown in  FIGS. 21A-21F  may not be inserted within the assembly at the same time, these cross-sections are intended to be descriptive of the path of the pulmonary artery guidewire  276  through the adjustable cannulation assembly  172  as directed primarily by the pulmonary artery guidewire introducer  176 . The cross-section illustrated in  FIG. 21A  shows the respective locations of the IVC guidewire  270  within the IVC obturator  178 . The eccentric opening in the eccentric obturator cap  180  is located such that the first IVC obturator  178  is close to the wall of the external port  158  of the cannulation coupler  146  when inserted into the adjustable cannulation assembly  172 . Moving towards the cross-section illustrated in  FIG. 21B , the neck  200  of the pulmonary artery guidewire introducer  176  and the placement of the pulmonary artery guidewire  276  positioned within is shown in its location relative to the first IVC obturator  178  within the base port  156  of the cannulation coupler  146 . The cross-section illustrated in  FIG. 21C  shows the location of the IVC obturator  178  and the pulmonary artery guidewire introducer  176  within the IVC cannula  174 , along with the respective locations of the IVC guidewire  270  and pulmonary artery guidewire  276 . The complimentary shape of the body  240  portion of the pulmonary artery guidewire introducer  176  compared to the outer circumference of the IVC obturator  178  ensures proper orientation and direction of the pulmonary artery guidewire  276  through the adjustable cannulation assembly  172 . The neck  200  configuration, combined with the complimentary shape and contour of the body  240  portion of the pulmonary artery guidewire introducer  176  allow the pulmonary artery guidewire introducer  176  to be inserted into the adjustable cannulation assembly  172  in a manner that enables the pulmonary artery guidewire  276  to be inserted into the side inflow branch  150  of the cannulation coupler  146  and pass around the outer circumference of the IVC obturator  178  in order to exit from the side port  186  of the IVC cannula  174  of the adjustable cannulation assembly  172 . The cross-section illustrated in  FIG. 21D  illustrates a position where the pulmonary artery guidewire  276  has been passed through the aperture  244  within the pulmonary artery guidewire introducer  176 , as previously described in regard to  FIGS. 18A-18B , and has moved from the first side channel  250  in the neck  200  over through the aperture  244  to the second side channel  246  within the pulmonary artery guidewire introducer  176 . The cross-section illustrated in  FIG. 21E  shows a position further down the adjustable cannulation assembly  172  where the side port interlock feature  248  of the pulmonary artery guidewire introducer  176  meets the side port  186  of the IVC cannula  174 , and the pulmonary artery guidewire  276  exits the side port interlock feature  248  and the side port  186  into the right atrium  260  as first described in regard to  FIG. 19E . The cross-section illustrated in  FIG. 21F  shows a position below the side port  186  on the IVC cannula  174 , where the IVC obturator  178  is no longer positionally constrained by either the pulmonary artery guidewire introducer  176  or the eccentric opening in the eccentric obturator cap  180 . 
       FIGS. 22A and 22B  are side views of the embodiment of an adjustable cannulation assembly discussed previously in  FIG. 9A-9C , illustrating adjustment of the second lumen  138  relative to the first lumen  132 . One benefit of the system and approach described herein is that the relative position of the lumen  138 ,  132  can be adjusted for each unique patient anatomy. In other words, the second lumen  138  does not need to stick out a fixed distance from the first lumen  132 . As shown in  FIG. 22A , the second lumen  138  may be extended  294  relative to the first lumen  132 . Similarly, as shown in  FIG. 22B , the second lumen  138  may be retracted relative to the first lumen  132 . 
     Various advantages of an adjustable cannulation assembly and methods thereof have been discussed above. Embodiments discussed herein have been described by way of example in this specification. It will be apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example only, and is not limiting. As just one example, although the end effectors in the discussed examples were often focused on the use of a scope, such systems could be used to position other types of surgical equipment. Various alterations, improvements, and modifications will occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested hereby, and are within the spirit and the scope of the claimed invention. The drawings included herein are not necessarily drawn to scale. Additionally, the recited order of processing elements or sequences, or the use of numbers, letters, or other designations therefore, is not intended to limit the claims to any order, except as may be specified in the claims. Accordingly, the invention is limited only by the following claims and equivalents thereto.