Abstract:
Extracorporeal life support (ECLS) systems, devices and methods wherein a portable ECLS device is used to deliver cardiovascular support to a humans or animal patient (or harvested organ(s)) during pre-hospital or inter-hospital transport.

Description:
TECHNICAL FIELD 
       [0001]    The present application relates generally to the fields of medicine and biomedical engineering and more particularly to devices and methods for performing cardiopulmonary bypass in human or non-human animal subjects. 
       BACKGROUND 
       [0002]    Pursuant to 37 CFR 1.71(e), this patent document contains material which is subject to copyright protection and the owner of this patent document reserves all copyright rights whatsoever. 
         [0003]    In extracorporeal life support (ECLS), blood is removed from a subject&#39;s circulatory system and channeled through an ECLS system wherein the blood becomes oxygenated and carbon dioxide is removed. The oxygenated blood is then delivered back into the subject&#39;s circulatory system. Most ECLS systems include pumps which propel or circulate the blood through the subject&#39;s vasculature thereby assuming the function of both the heart and lungs, even if the subject&#39;s heart is stopped or beating inefficiently. Other ECLS systems (e.g., the Novalung System, Novalung GmbH, Heilbronn, Germany) provide pumpless extracorporeal lung assist by oxygenating and removing carbon dioxide from the blood while relying on the subject&#39;s beating heart to adequately circulate the blood through the device and through the subject&#39;s vasculature. 
         [0004]    In general, ECLS techniques include extracorporeal membrane oxygenation (ECMO) as well as cardiopulmonary bypass (CPB). ECMO is essentially a form of partial CPB. ECMO is typically used for extended periods of time (e.g., days) while CPB is used for relatively short periods (e.g., hours). CPB has traditionally been used during cardiac and aortic surgical procedures wherein the heart is stopped. Generally, in ECMO vascular access is achieved by inserting cannulas into peripheral blood vessels using percutaneous technique or superficial surgical cut and then advancing the cannulas to locations in the central vasculature (e.g., vena cava, right atrium, aorta). In CPB vascular access is typically accomplished by intraoperative connection of cannulas to intrathoracic blood vessels. 
         [0005]    ECMO can be performed either as venoarterial ECMO (VA-ECMO) or venovenous ECMO (VV-ECMO). In VA-ECMO, deoxygenated blood is removed from a vein and the oxygenated blood is returned into an artery. In VA-ECMO the system typically pumps the blood under pressure to partially support the subject&#39;s cardiac output while W-ECMO generally provides extracorporeal lung assist but does not support cardiac function. 
         [0006]    In the past, ECLS systems were typically available only at major medical centers where specialized personnel (e.g., cardiothoracic surgeons and/or perfusionists) could be called upon to set up and operate the ECLS systems. Patients in the field, or those who presented at smaller hospital emergency departments, after suffering severe cardiac events or lung injuries would typically have to undergo (and survive) transport by vehicle (e.g., ground ambulance, helicopter, etc.) to a major medical center before having any possibility of ECLS treatment. 
         [0007]    In recent years, efforts have been made to develop small, automated, simplified, portable ECLS systems that could be used to deliver ECLS treatment to patients at smaller hospitals and during transport, without the need for specialized personnel. Examples of such devices include those described in U.S. Pat. Nos. 7,367,540; 7,597,546; 7,682,327; 7,846,122; 8,529,488; 8,529,488; 8,187,214; 8,568,347; 8,951,220; 8,834,399; 8,882,693; 8,721,579 and 8,844,336 as well as United States Patent Application Publication Nos. US2014/0142491; US2014/0326678 US2015/0056601; US2015/0141897; US2015/0073335 and US2015/0082863, the entire disclosure of each such patent and patent application being expressly incorporated herein by reference. 
       SUMMARY 
       [0008]    Various embodiments described herein provide certain advances and improvements for portable ECLS systems aimed at enhancing their automated set up and/or operation as well as their mobility and use in transport vehicles (e.g., ambulances, helicopters, watercraft, etc.) 
         [0009]    An ECLS system which comprises an extracorporeal life support device having an inlet connectable to the vasculature of a human or animal subject or harvested organ(s), an outlet also connectable to the vasculature of the subject or organ(s) and gas exchange apparatus operable to a) receive deoxygenated blood from the vasculature of the subject or organ(s) via the inlet, b) oxygenate the blood and c) infuse the oxygenated blood into the vasculature of the subject or organ(s) via the outlet is described herein. One or more of the following components may be provided separately or in combination with an ECLS system:
       a) a transport accessory kit comprising apparatus useable during transport of the subject or organ(s) while receiving treatment from the extracorporeal life support device;   b) a clinical accessory kit comprising apparatus useable while the subject or organ(s) is/are receiving treatment from the extracorporeal life support device;   c) securement member(s) or anchoring belt or strap assemblies for securing the extracorporeal life support device to a floor or other surface in a transport vehicle such as a wheeled vehicle (ground ambulance, rescue or military vehicle), aircraft (helicopter or fixed wing aircraft) or watercraft (rescue boat, military landing craft, etc.)   d) a wheeled cart for transporting the extracorporeal life support device over a floor, road or other substantially horizontal surface (e.g., from a location inside a hospital to a waiting transport vehicle); and   e) a controller programmed to perform controlled start up pre-testing of the extracorporeal life support device and to issue separate error signals to indicate different types of errors detected during the start up pre-testing.       
 
         [0015]    Methods for preparing, testing and using ECLS systems of the foregoing character, including a method for using a transport vehicle to transport a subject or harvested organ(s) from a first location to a second location while the subject or organ(s) is/are receiving treatment from the extracorporeal life support system are described herein. 
         [0016]    In certain embodiments, a system or device comprising a conduit that is connectable to a subject&#39;s body, a controller, a pump and a sensor which senses pressure or flow within the conduit and transmits indicia of the sensed pressure or flow to the controller; wherein the pump creates negative pressure within the conduit to thereby withdraw a body fluid from the subject&#39;s body through the conduit, and the controller is programmed to determine when the sensed pressure or flow has fallen below a predetermined minimum and to thereafter issue control signals to the pump causing the pump to slow or stop until the sensed pressure or flow has risen above the predetermined minimum is provided. Such device or system may in some embodiments comprise an ECLS device or system in which the withdrawn body fluid is blood. However, this aspect or feature may be utilized in many other types of devices and systems including but not limited to apheresis systems and devices, autotransfusion systems and devices, hemodialysis systems and devices, hemofiltration systems and devices, plasmapheresis systems and devices and photopheresis systems and devices. 
         [0017]    In other embodiments, there is provided an extracorporeal device having a conduit, a pump, a monitoring unit, a controller and a bubble sensor, wherein the pump circulates fluid through the conduit; the bubble sensor senses when a gas-liquid transition occurs within the conduit; the bubble sensor transmits a signal to at least the monitoring unit when a gas-liquid transition is sensed and the monitoring unit is programmed to issue an alarm or notification in response to the sensing of a gas-liquid transition by the bubble sensor; the controller is programmed to cause the system to take at least one remedial action in response to the sensing of a gas-liquid transition by the bubble sensor; and the controller is further programmed to perform a system test and a bubble sensor test while the conduit is initially being primed with fluid and/or during priming of the conduit with fluid and to provide a bubble sensor test failure indication and a system test failure indication; wherein the bubble sensor test failure indication is separate from the system test failure indication. In some embodiments a single gas-liquid transition occurs in the conduit during priming of the conduit and the bubble sensor test is timed to detect that single gas-liquid transition. In other embodiments, multiple gas liquid transitions may occur during priming of the conduit and the bubble sensor test is timed to detect at least one of those gas-liquid transitions. In some embodiments, gas may be volitionally introduced into the conduit (e.g., through a gas bubble injector) to create at least one gas-liquid transition for purposes of conducting the bubble sensor test. In at least some embodiments, the bubble sensor test and system test are performed sequentially as opposed to concurrently. 
         [0018]    Still further aspects and details of the present invention will be understood upon reading of the detailed description and examples set forth herebelow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The following detailed description and examples are provided for the purpose of non-exhaustively describing some, but not necessarily all, examples or embodiments, and shall not limit the scope of the invention in any way. 
           [0020]      FIG. 1A  is a perspective view of one embodiment of an ECLS system which includes an extracorporeal life support device positioned on a cart along with several accessory devices. 
           [0021]      FIG. 1B  is a side view of a clinical accessory kit that may optionally be included in the system of  FIG. 1A . 
           [0022]      FIG. 1C  is a top view of the clinical accessory kit of  FIG. 1B  in an opened configuration which reveals the kit&#39;s contents including: an AC power cord(s), a gas supply and an emergency drive device. 
           [0023]      FIG. 1D  is a side view of a transport accessory kit that may optionally be included in the system of  FIG. 1A . 
           [0024]      FIG. 1E  is a top view of the transport accessory kit of  FIG. 1D  in an opened configuration which reveals the kit&#39;s contents including: transport power cord(s), strap(s) for attaching the transport kit to the extracorporeal life support device and a DC power supply device. 
           [0025]      FIG. 1F  shows examples of two types of transport power cords that may be included in the transport accessory kit to facilitate connecting the DC power supply to DC current outlets of a type commonly available in medical transport vehicles. 
           [0026]      FIG. 2A  is a right side view of the extracorporeal life support device of  FIG. 1A  equipped with anchoring belt assemblies having forward and aft anchoring belts for attaching the extracorporeal life support device to the floor of a transport vehicle and having the transport accessory kit of  FIG. 1D  attached to the top of the extracorporeal life support device. 
           [0027]      FIG. 2AA  is an enlarged view of region  2 AA of  FIG. 2A  with a cover flap on the transport accessory kit lifted to reveal the manner in which a strap is used to attach the transport accessory kit to the extracorporeal life support device. 
           [0028]    FIG.  2 AAA is a top view of the transport accessory kit portion of the system of  FIG. 2A  showing the manner in which the DC power supply is operatively positioned on top of the transport accessory kit and held in place by DC power supply securement belts. 
           [0029]      FIG. 2B  is a left side view of the system of  FIG. 2A . 
           [0030]      FIG. 2C  shows the right and left anchoring belt assemblies used with the system shown in  FIGS. 2A and 2B . 
           [0031]      FIG. 3  is a schematic flow path and component diagram of one embodiment of an extracorporeal life support device. 
           [0032]      FIG. 4  is a screen shot showing an example of information that may appear on a user interface screen of an extracorporeal life support system during preparation and pre-testing of the system. 
           [0033]      FIG. 5  is another screen shot showing an example of information that may appear on a user interface screen of an extracorporeal life support system during preparation and pre-testing of the system. 
           [0034]      FIG. 6  is another screen shot showing an example of information that may appear on a user interface screen of an extracorporeal life support system during preparation and pre-testing of the system. 
           [0035]      FIG. 7  is another screen shot showing an example of information that may appear on a user interface screen of an extracorporeal life support system during preparation and pre-testing of the system. 
           [0036]      FIG. 8  is another screen shot showing an example of information that may appear on a user interface screen of an extracorporeal life support system during preparation and pre-testing of the system. 
           [0037]      FIG. 9  is another screen shot showing an example of information that may appear on a user interface screen of an extracorporeal life support system during preparation and pre-testing of the system. 
           [0038]      FIG. 10A  shows an example of an error message that may be displayed on a user interface screen of an extracorporeal life support system when certain conditions are encountered during preparation and pre-testing of the system. 
           [0039]      FIG. 10B  shows another example of an error message that may be displayed on a user interface screen of an extracorporeal life support system when certain conditions are encountered during preparation and pre-testing of the system. 
           [0040]      FIG. 10C  shows another example of an error message that may be displayed on a user interface screen of an extracorporeal life support system when certain conditions are encountered during preparation and pre-testing of the system. 
           [0041]      FIG. 10D  shows another example of an error message that may be displayed on a user interface screen of an extracorporeal life support system when certain conditions are encountered during preparation and pre-testing of the system. 
           [0042]      FIG. 11  is a perspective view of a cart device which may optionally be used in conjunction with an extracorporeal life support system. 
           [0043]      FIG. 12  is a perspective view of an extracorporeal life support device and transport accessory kit placed in a transport position in the cart of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0044]    The following detailed description and the accompanying drawings to which it refers are intended to describe some, but not necessarily all, examples or embodiments of the invention. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The contents of this detailed description and the accompanying drawings do not limit the scope of the invention in any way. 
         [0045]      FIG. 1A  shows a system  10  comprising an ECLS device  12  positioned on a cart  14  along with an AC power supply  21 , an emergency derive apparatus  32   a  and a gas bottle  23 . In this example, the ECLS device  12  generally comprises a reusable base module  20  and a disposable patient module  22 . 
         [0046]    The ECLS device  12  is useable for providing oxygenated blood to a human or animal subject or to vascularized organ(s) that have been explanted from a human or animal donor for subsequent transplantation (e.g., heart, lungs, heart &amp; lungs, kidney, etc.). As described more fully below, the ECLS device includes, at minimum, an inlet which is connectable to vasculature of the subject or organ(s), an outlet which is also connectable to vasculature of the subject or organ(s) and gas exchange apparatus operable to oxygenate blood. In operation, the oxygenation apparatus receives deoxygenated blood from the subject or organ(s) via the inlet. The blood then becomes oxygenated by the oxygenation apparatus and the oxygenated blood then returns, via the outlet, into the vasculature of the subject or organ(s). In its most basic form, the ECLS device  12  is useable for VV-ECMO and other forms of extracorporeal lung assist. However, in many embodiments this ECLS device  10  may also include non-pulsatile or pulsatile blood pumping apparatus useable to propel or circulate the blood through the device  10  and through the vasculature of the subject or organ(s). The inclusion of such pumping apparatus will render the ECLS device  12  useable for full circulatory support procedures, such as VA-ECMO and CPB, as well. The ECLS device  12  may optionally include numerous other components, some examples of which are seen in the diagram of  FIG. 3  and described below, and may be controlled by a programmable controller which communicates with a user interface  24 , such as an LCD display. Non-limiting examples of apparatus useable as the ECLS device  12  include those described in at least some of the above-incorporated U.S. Pat. Nos. 7,367,540; 7,597,546; 7,682,327; 7,846,122; 8,529,488; 8,529,488; 8,187,214; 8,568,347; 8,951,220; 8,834,399; 8,882,693; 8,721,579 and 8,844,336 as well as United States Patent Application Publication Nos. US2014/0142491; US2014/0326678 US2015/0056601; US2015/0141897; US2015/0073335 and US2015/0082863. 
         [0047]    In some embodiments, the system  10  may include a clinical accessory kit  16 , an example of which is seen in  FIGS. 1B and 1C . Such clinical accessory kit  16  may comprises a housing or case  26 , such hard or soft-sided bag, which contains accessories useable for operation of the ECLS device under routine conditions or in the event of non-routing conditions such as power outages or when an available source of compressed oxygen or oxygen enriched air is unavailable for operation of the device&#39;s oxygenator. In the example shown, the clinical accessories in the kit  16  include a compressed gas source  30 , which may be a cylinder filed with 100% oxygen or other oxygen containing gas mixture suitable for use in operating the device&#39;s oxygenator. As an alternative to a gas filled cylinder as seen in  FIG. 1C , the compressed gas source could comprise any other suitable source of oxygen such as an oxygen concentrator or a chemical oxygen generator. Oxygen concentrators typically concentrate oxygen from ambient air. Chemical oxygen generators normally use sodium chromate (NaClO 3 ) along with smaller amounts of other chemicals and convert this chemical to oxygen flow when the source is activated. The release of oxygen from the sodium chromate is accomplished by igniting the chemical. When converting the sodium chromate to oxygen a byproduct of the chemical reaction is heat. Thus, embodiments which employ a chemical oxygen generator may also include apparatus for dissipation or control of heat generated by the reaction. This clinical accessory kit  16  may also include a battery powered emergency drive  32   b  useable for driving a pump or other components of the ECLS device  10  in the event of a power outage or component failure. This emergency drive  32   b  may be battery or hand powered and useable to operate at least the blood pump and other critical components of the device  12  during a power outage or when other power is unavailable. Also, in this example, the clinical accessory kit  16  may include a power cord, e.g., an AC power cord, for connecting the device  10  to an electrical power outlet of the type typically available in hospitals or other buildings. 
         [0048]    To facilitate its portability and transport, some embodiments of the system  10  may include a transport accessory kit  18 , one example of which is seen in  FIGS. 1D, 1E and 2A through 2B . In this example, the transport accessory kit  18  comprises a housing or case  28 , such hard or soft-sided bag, which contains accessories useable during transport of the system  10 . In this example, the accessories include a DC power supply  36 , one or more transport power cord(s)  38  and strap(s)  19  or other attachment members useable for attaching the transport kit case or bag  28  to the ECLS device  12  during transit. The power cord(s) is/are useable for connecting the DC power supply  36  to a power outlet of the type commonly available in transport vehicles. The DC power supply  36  converts the voltage of the current received from the vehicle outlet to that used by the ELCS device  12 , e.g., 31 VDC.  FIG. 1F  shows two examples of specialized transport power cords  38   a ,  38   b  that may be included in the transport accessory kit  18 . Each of these specialized cords  38   a  and  38   b  is equipped with plug connectors configured for use with different types of DC electrical outlets found in many ground ambulances and helicopters. Power cord  38   a  is typically used in ground ambulances and power cord  38   b  is typically used in helicopters. The strap(s)  19  is/are useable for securing the transport kit case  28  to the ECLS device  12  in a manner shown in  FIGS. 2A through 2B  and described more fully herebelow. 
         [0049]      FIGS. 2A and 2B  show right and left side views of the ECLS device  12  equipped with anchoring belt assemblies  42 R,  42 L and having the transport accessory kit  18  secured in a transport position on top of the ECLS device  12  by belt  19 .  FIGS. 2AA  and  2 AAA show details of the manner in which the transport accessory kit  18  is deployed and secured on top of the ECLS device  12 .  FIG. 2C  shows the anchoring belt assemblies  42 R,  42 L separately. 
         [0050]    As seen in  FIGS. 2A and 2B , the anchoring belt assemblies  42 R,  42 L comprise first (e.g., forward) and second (e.g., rear) pivoting connectors  46 ,  48  which are attached securely to the right and left sides of the ECLS device  12 . Each fixed-length first (e.g., forward) belt or other strap member  40 R,  40 L is attached at one end to the first pivoting connectors  48  on that side of the device  12  and each variable-length aft or rear belt or strap  41 R,  41 L is attached to the second pivoting connector  46  on that side of the device  12 . The variable-length second belts  41 R,  41 L are equipped with adjustment mechanisms  52 R,  52 L useable for cinching or adjusting the length of the second belts  41 R,  41 L. Any suitable type of adjustment mechanism(s) may be used. Examples of suitable adjustment mechanisms include; Cam Buckle Anodized #75003 and Tie Down Stud #110218 available from Allsafe Jungfalk GmbH &amp; Co. KG, Gerwigstraβe 31, 78234 Engen, Germany. The first belts  40 R,  40 L are directed toward the front of the ECLS device where the controls used during transport are located. 
         [0051]    During transport it is usually important for the front of the ELCS device  12  to be facing the transport caregiver so that the caregiver when needed can easily access the controls. To avoid inadvertent placement of the ECLS device  12  in the inverted direction, the first belts or straps  40 R,  40 L may be color coded so as to be visually discernible from the second or rear belts or straps  41 R,  41 L. For example, the first belts  40 R,  40 L may be red and the second belts  41 R,  41 L may be black. In other embodiments, the first and/or second belts may include markings or other indicators to distinguish between the two types of belts. The ELCS device  12  itself may include markings or other indicators to ensure it is loaded into a transport vehicle in the proper orientation such that the front of the ELCS device  12  is facing the transport caregiver for ease of access to the controls. 
         [0052]    In operation, as shown in  FIGS. 2A and 2B , the anchoring belt assemblies  42 R,  42 L may be pre-attached to the sides of the ECLS device  12  or they may be stored elsewhere, such as in the transport kit case  28 , and then attached to the sides of the ECLS device  12  when needed. Any suitable connection material or apparatus may be used for permanently or releasably connecting the anchoring belt assemblies  42 R,  42 L to the device  12 . For example, the anchoring belt assemblies  42 R,  42 L may be connected to the ECLS device  12  via a quick connect or clipping mechanism, such as pins located on the back side of the belt assembly, or the backside of a bracket or pivoting connectors  46 ,  48  of the belt assemblies, which may be inserted into or coupled to corresponding holes or slots on the sides of the ECLS device  12 . The anchoring belt assemblies  42 R,  42 L may be attached to the ECLS device  12  before or after loading the ECLS device  12  into a transport vehicle. When not attached to the ECLS device for transport, the with anchoring belt assemblies  42 R,  42 L may be disconnected and stored elsewhere, such as in the transport accessory kit housing or case  28 . The back side of an attached anchoring belt assembly or its attachment bracket may optionally include pads or rubber puffers to reduce scratching. 
         [0053]    The ECLS device  12 , with its attached belt assemblies  42 R,  42 L, may be loaded into the transport vehicle along with the subject (or the harvested organ(s)) receiving treatment from the ECLS device  12 . The color coding of the anchoring belts  40 R,  40 L,  41 R,  41 L may be observed and referenced to ensure that the ECLS device  12  is loaded into the vehicle in the right direction (i.e., with its front side facing in the direction of the caregiver&#39;s seat or usual location within the vehicle). This typically will require the first belts  40 R,  40 L to be directed toward the front of the vehicle and the second belts  41 R,  41 L to be directed toward the rear of the vehicle. Alternatively, the ECLS device may be loaded into the transport vehicle in the proper direction and the belt assemblies  42 R,  42 L, may subsequently be attached to the ECLS device. 
         [0054]    After the ECLS device has been loaded into the transport vehicle, the free ends of the fixed-length first belts  40 R,  40 L are attached to desired first anchoring locations which are adjacent to one another at a first region of the floor or other surface(s) of the vehicle and the free ends of the variable-length second anchoring belts  41 R,  41 L are anchored to desired second anchoring locations which are adjacent to one another at a second region of the floor or other surface(s) of the vehicle. Thereafter, the adjustment mechanisms  52 R,  52 L are used to cinch or shorten the variable-length second anchoring belts  41 R,  41 L thereby causing the belts to be sufficiently taught to firmly hold the ECLS device  12  in position within the vehicle. In many instances, the floor of the transport vehicle will be equipped with recessed tracks and the free ends of the belts  40 R,  40 L,  41 R,  41 L will be equipped with hardware that allows them to be inserted into and affixed to desired locations within those recessed tracks, thereby establishing the appropriate anchoring locations for holding the ELCS device  12  in its intended position. In certain embodiments, one or more first belts may be a variable-length belt and one or more second or rear belts may be a fixed-length belt. In other embodiments, any combination of fixed-length and variable-length belts may be utilized for the first and/or the second or rear belts. 
         [0055]    Additionally, to facilitate use of the ECLS device  12  during transport the securement belt  19  may be removed from the transport accessory kit  18  and used to attach the remainder of the transport accessory kit  18  to a transport position on top of the ECLS device  12 , as seen in  FIGS. 2A  and  2 B. To accomplish this, the user may lift a flap  39  at one end of the transport accessory case or bag  28  to expose a thru-slot or channel  25  that extends through the case or bag  28 . The strap  19  may be fed through such slot or channel  25  and passed around the bottom of the ECLS device  12 . The strap  19  is equipped with a cinching buckle  53  which is connected and used to cinch or shorten the strap  19  until the strap  19  is sufficiently taught to hold the transport kit case or bag  28  in the transport position on top of the ECLS device  12 , as shown. 
         [0056]    The appropriate power cord  38  is selected for use and removed from the transport kit case or bag  28  along with the DC power supply  36 . One end of the selected power cord  38  is plugged into an electrical power outlet of the vehicle and the other end is plugged into an input jack of the DC power supply  36 . The case or bag  28  may then be closed and the DC power supply placed on top of the case or bag  28  and held in place by straps  37  as shown in FIG.  2 AAA. The power supply cord  35  of the DC power supply  36  is plugged into power input jack  39  of the ECLS device  12 . Thus, the electrical current from an outlet in the transport vehicle is carried to the DC power supply  36  by a selected cord  38 . The DC power supply then adjusts the voltage of the received power, as needed, and delivers the desired voltage of DC current through the power supply cord  35  to the ECLS device  12 . The ECLS device  12  may be equipped with a battery backup to supply short term power to the device  12  during periods when it is not receiving externally sourced power through either the AC power supply  21  (typically used in hospital) or DC power supply (typically used in the transport vehicle). 
         [0057]    As explained above, ECLS devices  12  of varying type and complexity may be used in conjunction with the transport facilitating kits, belt assemblies and other components/methods described herein.  FIG. 3  shows a schematic component diagram  60  of one non-limiting example of an automated ECLS device  12  that may be used in some embodiments described herein. The components shown in this component diagram  60  include an inlet line  64 , priming line  66  with clamp  74 , reservoir  62  with blood level sensors  68 , vent line  71  and vent pump  72 , reservoir outlet line  80 , blood pump  86 , pump to oxygenator line  88 , blood oxygenator  92 , oxygenator to filer line  94 , blood filter  98 , outlet line  100  with bubble detector  102 , fast clamp  104  and flow sensor  106 , recirculation line  107  with shunt clamp  108  and controller C. Pressure sensors  70 ,  90  and  96  are also present on the reservoir vent line  71 , pump to oxygenator line  88  and oxygenator to filter line  94 , respectively. The controller C and monitoring unit MU are connected, by wired or wireless connectivity, to the user interface  24  as well as certain of the components  60 . The monitoring unit MU may be programmed to receive and process signals from various sensor components. The controller C may be programmed to issue control signals to various operational components, thereby controlling operation of the ECLS device  12 , as described herein. 
         [0058]    In typical operation, the components  60  are initially filled with a priming fluid. Priming line clamp  74  may be opened and a suitable priming fluid, such as sterile 0.9% NaCl solution (saline), may be introduced through the priming line  66  while the controller C operates the pumps  72 ,  86  in a manner that fills all components with the priming fluid. As discussed in more detail below, during or after the priming process the controller C may cycle through certain pre-treatment tests, such as a system or performance test and a bubble detector test. A critical aspect of the operation of the system is to avoid inadvertent introduction of clinically significant gas emboli (e.g., bubbles) through the outlet line and into the patient&#39;s vasculature. 
         [0059]    When it is desired to commence the ECLS treatment, the inlet line  64  is connected to the patient&#39;s vasculature, typically via a cannula that has been advanced to a central venous location such as the patient&#39;s vena cava or right atrium. The outlet line  100  is also connected to the patient&#39;s vasculature, typically via a cannula that has been advanced to a central arterial location such as the patient&#39;s aorta. The controller C causes the blood pump  86  to circulate blood through the system components  60  and, in at least cases where the patient is in cardiac arrest or has clinically insufficient cardiac output, the blood pump  86  creates sufficient flow and pressure to also circulate blood through the patient&#39;s vasculature. Incoming de-oxygenated blood fills the reservoir  62  and any gas that collects at the top of the reservoir due to degassing of the blood or other causes is removed through vent line  71  with or without active pumping by the vent pump  72 . Deoxygenated blood from the reservoir  62  then flows though lines  80  and  88  into oxygenator  92 . In the oxygenator, gas exchange occurs through membranes such that carbon dioxide is removed from the blood and oxygen is added to the blood. The resultant oxygenated blood then flows through line  94 , through filter  98  and though the outlet line  100 . The filter  98  captures any solid embolic material, such as small or microscopic blood clots, that may be present in the blood. In routine operation, the oxygenated blood flows though the outlet line, the bubble detector detects no bubbles, the fast clamp  104  remains open and the oxygenated blood flows into the patient&#39;s vasculature as intended. However, if the bubble detector  102  senses a bubble, it immediately sends a bubble detection signal to the monitoring unit MU and the controller C. In response to that bubble detection signal, the monitoring unit MU causes a bubble detection error signal to appear at the top of the display screen of user interface  24  and the controller C promptly issues control signals to the fast clamp  104  and shunt clamp  108  causing the fast clamp  104  to close before the detected bubble has flowed past it and causing shunt clamp  108  to open. As a result, the flow of blood into the patient ceases and the blood (including the detected air bubble) is shunted through recirculation line  107 , through inlet line  64  and back into the reservoir  62 . This recirculation continues until the detected bubble  9  (and any others) have been separated from the blood in reservoir  62  and ultimately removed through vent line  71 . After the recirculation has proceeded for a desired period of time with no further bubbles being detected by the bubble detector  102 , the controller C causes shunt clamp  108  to close and fast clamp  104  to open, thereby returning the system to its normal mode of operation with deoxygenated blood being removed from the patient&#39;s vasculature and oxygenated blood being returned into the patient&#39;s vasculature. It is important that the fast clamp  104  comprise a clamping or valving device that closes rapidly enough after a bubble is sensed by the bubble detector  102  to prevent the detected bubble from passing into the subject&#39;s vasculature. One example of a fast closing clamp useable in this application is that described in U.S. Pat. No. 7,367,540 (Brieske) entitled Fast Closing Clamp, the entire disclosure of which is expressly incorporated herein by reference. 
         [0060]    During operation, running of the blood pump  86  and/or vent pump  72  causes negative pressure in the inlet line  64  and positive pressure in the outlet line  100 . Occasionally, the negative pressure in the inlet line  64  may become excessive, especially if the overall amount of fluid in the extracorporeal circuit is low and the blood pump  86  is running at high speed. Excessive negative pressure in the inlet line  64  can have adverse consequences. For example, it may cause the tip of the inlet blood cannula to become suction-attached to the wall of the blood vessel in which it is positioned, potentially causing damage to the blood vessel. Also, the blood reservoir  62  could run dry or damages (e.g., leaks) could occur in system components  60 . To deal with this potential problem, an additional pressure sensor (not shown) could optionally be present on the inlet line  64  and the Controller C could optionally be programmed to receive and process signals from that inlet line pressure sensor and, if the negative pressure in the inlet line exceeds a predetermined maximum, to issue control signals to the blood pump  86  and/or vent pump  72  causing the pump(s)  86  and/or  72  to reduce speed. This controlled reduction in pump speed will cause the venous pressure to rise in the inlet line until it reaches a desired pressure. This may be accomplished by any suitable programming of the controller C. One manner in which the controller C may be programmed to accomplish this is by Pressure Feedback Control with the following parameters:
       Pressure Measurement Unit: mmHg   Pressure Measurement Update Interval: 300 ms   K p  (proportional gain): 5   K i  (integral gain): 1   K d  (derivative gain): 0.6 (PV&lt;SP)   K d  (derivative gain): 0.3 (PV&gt;SP)   Where:   PV=Process Variable (venous inlet pressure)   SP=Set point (venous inlet pressure limit)   K p =Proportional gain   K i =Integral gain   K d =Derivative gain       
 
         [0073]    The derivative gain K d  has two values because the speed of the blood pump should decrease very fast if the venous line gets kinked but the speed should increase only slowly if the operator changes the set point. In this example, the pressure feedback control is only active if the set limit of the blood pump is higher than 1500 rpm. A warning message is displayed, such as via a user interface  24 , if the pressure feedback control does momentarily reduce the speed of the blood pump  86 . Also, in this example, the pressure feedback control can be switched on/off, such as via a sensor settings menu on a user interface  24  but the default setting will be with the pressure feedback control switched on. 
         [0074]    Any suitable pressure limits may be used. For example, the default value for the set limit of the deoxygenated blood pressure in inlet line  64  may be −120 mmHg. An indicator, such as a bar indicator on a user interface  24 , may change appearance (e.g., change from green/red to grey) if the pressure feedback control is switched off. Neither the controller C nor monitoring unit MU supervise the venous pressure if the pressure feedback control is switched off. 
         [0075]    The optional pressure feedback control described herein is not only useable in ECLS systems, but may be incorporated into any extracorporeal device or system that draws a body fluid (e.g., blood) from the body of a patient and is equipped with a pump and a controller. Examples of non-ECLS types of devices in which this pressure feedback control feature may be incorporated include but are not limited to devises used for apheresis, autotransfusion, hemodialysis, hemofiltration, plasmapheresis, photopheresis, etc. 
         [0076]    ECLS devices  12  may also include modifications to the controller software aimed at streamlining the initial start-up and testing of the ECLS device. Specifically, as mentioned above, the ECLS device may include a controller C, which may be programmed to perform self-tests of the overall system performance and bubble detector and to display information and error signals in ways that facilitate rapid location and correction of any detected problems.  FIGS. 4 through 9  are screen shots showing examples of information that may appear on the screen of the user interface  24  during preparation and pre-testing of the ECLS device  12 .  FIGS. 10A through 10D  show enlarged views of the error signals associated with each of the screen shots shown in  FIGS. 4 through 8 . 
         [0077]      FIGS. 4 and 10A  show information displayed on the screen of the user interface  24  during the device performance or system test. With reference to the device components shown in  FIGS. 1A and 3 , this performance or system test checks whether the device  12 , after the patient module  22  has been fully filled with fluid, can generate pre-determined flow rates. The device  12  has clamps that directly affect the flow rate. Because of this, the performance test includes three separate test steps. In Step #1, flow is measured by flow sensor  106  while the blood pump  86  operates at constant speed with shunt clamp  108  open and fast clamp  104  open. Thereafter, in Step #2, flow is measured by flow sensor  106  while the blood pump  86  operates at constant speed with shunt clamp  108  open and fast clamp  104  closed. Thereafter, in Step #3, flow is measured by flow sensor  106  while the blood pump  86  operates at constant speed with shunt clamp  108  closed and fast clamp  104  closed. Both purge clamps  76 ,  78  are closed during all three steps of the performance test. The filling clamp  74  has no effect on the flow rate. All single fault error modes can be detected. 
         [0078]    In the example shown, the system also performs a pre-test of the bubble sensor  102 . The bubble sensor  102  has two independent channels. Two analog signals are transmitted from the bubble sensor  102  and are converted to square root signals. One square root signal gets evaluated by the controller C and the other square root signal gets evaluated by the monitoring unit MU. During filling of the patient module air in line  100  is displaced by liquid being pumped through the system by the blood pump  86 . For certain types of blood pumps, this may occur as a single air to liquid transition. For other types of blood pumps, multiple air-liquid transitions may occur (i.e., air-liquid-air-liquid-, etc.) before a constant flow of liquid is achieved through line  100 . Both square root signals may transit from permanent high (air) to a periodic square root signal (liquid). Every conceivable single fault error, like sensor errors or a cable break, may prevent this transition from happening on at least one evaluation unit. Therefore the result of the bubble sensor activation is very reliable and the patient module can be regarded as bubble free. 
         [0079]      FIGS. 5 and 10A  show information displayed on the screen of the user interface  24  when the bubble sensor  102  detects an air bubble after its activation. During the initial priming of the system, it is not unlikely for air bubbles to be detected. It is very likely that there are bubbles in the patient module. A sensor malfunction is still possible but, presuming that temperature has remained substantially constant, is unlikely because the bubble sensor  102  has previously passed the initial air/liquid transition test and the bubble sensor  102  is devoid of components that are likely to have degraded in the intervening time. 
         [0080]      FIGS. 6 and 10B  show information displayed on the screen of the user interface  24  when only the monitoring unit MU detects air bubbles after activation of the bubble sensor  102 . This displayed information may result from different situations. For example, it may result if the attenuation of the analog signal on the signal path to the controller C and to the monitoring unit MU are not exactly the same. Therefore, if a small bubble at the detection limit gets detected by the monitoring unit MU but not by the controller C, the monitoring unit MU will start the bubble elimination procedure described herein. In other examples, there may be false alarms or the signal path to the controller C may become unable to detect air bubbles, but it is likely that there are bubbles in the patient module (e.g., approximately 50% of the time). This error mode may also indicate a circuit board malfunction because the result of the monitoring unit signal path and the control unit signal path do not match. 
         [0081]      FIGS. 7 and 10C  show information displayed on the screen of the user interface  24  when a malfunction of the bubble sensor  102  is detected during system preparation. This error message can be caused by two different error modes: Error mode 1: Permanent high signal on the signal path to the monitoring unit (no air/liquid transition has been detected so far); Error mode 2: Permanent low signal on the signal path to the monitoring unit (possible cable break). There is only one error message for both error modes because the end result for the user is the same, i.e., the bubble sensor is not working. 
         [0082]      FIGS. 8 and 10D  show information displayed on the screen of the user interface  24  when a malfunction of the bubble sensor  102  is detected after system preparation. A permanent square root signal on the signal path to the monitoring unit indicates that no air has been detected so far. This error mode may be triggered by a partially filled patient module. This could occur when the user connects and opens the filling line to the patient module before the device  12  is powered on. The square root signals indicate that the bubble sensor is working but the system was unable to perform a full self-test of the bubble sensor. 
         [0083]      FIG. 9  shows information displayed on the screen of the user interface  24  when manual venting is performed. 
         [0084]    In certain embodiments, the ECLS devices described herein may run for extended periods of time, e.g., up to 14 days, or longer than 14 days. 
         [0085]      FIGS. 11 and 12  show a cart device  100  which may optionally be used for transporting the ECLS device  12  from a hospital building to a waiting transport vehicle or otherwise over an underlying floor or roadway surface. This cart  1000  comprises a frame  1002 , a plurality of wheels  1012  attached to and extending downwardly from the frame and a plurality of engagement members  1004  attached to and extending upwardly from the frame  1002 . The engagement members  1004  are located and configured so that the ECLS device  12  is positionable in a transport position (seen in  FIG. 11 ) such that the bottom of the ECLS device  12  rests upon the frame  1002  and the engagement members  104  register against locations on the sides of the ECLS device  12  to prevent the ECLS device  12  from slipping or sliding off of the transfer cart. In the particular example shown, the cart has four corners and an engagement member  1004  is positioned on each of the four corners. In this example, the engagement members  1004  are configured to include upstanding regions  1008  which engage sides of the extracorporeal device as well as depressions or cut-out regions  1006  shaped to receive the legs  1010  of the ECLS device as it is lowered onto the cart. The abutment of the legs  1010  and side walls of the ECLS device  12  against the engagement members  104  allows one to push the cart/device combination along a floor or underlying surface while the ECLS  12  device  12  stays firmly mounted on the cart  1000 . However, when it is desired to remove the ECLS device from the cart  1000 , such as when it is being loaded into a transport vehicle, the device  12  can be lifted upwardly so that it no longer contacts the engagement members  1004  and is thereafter free of the cart  1000 . 
         [0086]    It is to be appreciated that, although the invention has been described hereabove with reference to certain examples or embodiments of the invention, various additions, deletions, alterations and modifications may be made to those described examples and embodiments without departing from the intended spirit and scope of the invention. For example, any elements, steps, members, components, compositions, reactants, parts or portions of one embodiment or example may be incorporated into or used with another embodiment or example, unless otherwise specified or unless doing so would render that embodiment or example unsuitable for its intended use. Also, where the steps of a method or process have been described or listed in a particular order, the order of such steps may be changed unless otherwise specified or unless doing so would render the method or process unsuitable for its intended purpose. Additionally, the elements, steps, members, components, compositions, reactants, parts or portions of any invention or example described herein may optionally exist or be utilized in the absence or substantial absence of any other element, step, member, component, composition, reactant, part or portion unless otherwise noted. All reasonable additions, deletions, modifications and alterations are to be considered equivalents of the described examples and embodiments and are to be included within the scope of the following claims.