Patent Publication Number: US-2023146744-A1

Title: Fluid paths for angiography injector assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/990,141 filed on Mar. 16, 2020 and U.S. Provisional Patent Application No. 62/990,179 filed on Mar. 16, 2020, the disclosures of which are hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates generally to fluid injector systems and associated fluid path assemblies for high pressure injection of medical fluids. More specifically, the present disclosure describes a fluid delivery system and fluid path assembly having a downstream automated shutoff valve and an upstream air detector to minimize the chance of air being delivered to a patient during an injection procedure. 
     Description of Related Art 
     In many medical diagnostic and therapeutic procedures, a medical practitioner, such as a physician, injects a patient with one or more medical fluids. In recent years, a number of injector-actuated syringes and powered fluid injectors for pressurized injection of medical fluids, such as a contrast solution (often referred to simply as “contrast”), a flushing agent (such as saline or Ringer&#39;s lactate), and other medical fluids, have been developed for use in procedures such as cardiovascular angiography (CV), computed tomography (CT), ultrasound, magnetic resonance imaging (MRI), positron emission tomography (PET), and other imaging procedures. In general, these fluid injectors are designed to deliver a preset amount of fluid at a preset pressure and/or flow rate. In certain applications, such as angiography, the medical fluids may be injected directly into the cardiac system at fluid pressures up to 1200 psi. 
     During certain injection procedures at these high fluid pressures with fluid being administered directly to the cardiac system, it is imperative that no air or other gas bubble be co-injected with the medical fluid as patient harm may result. For angiography, injection of even small volumes of air during an injection procedure may be harmful and must be avoided. The danger associated with air injection during angiography procedures is enhanced since the fluids are injected directly into the cardiac system. Further, at pressures of up to 1200 psi, the speed at which the fluid (and inadvertent air bubbles) flow through the fluid path and the compressibility of gas relative to liquids compresses the volume of air bubbles in the fluid line compared to the same molar amount of air at lower pressures make stopping of an air bubble after detection and before injection into the patient a challenge. For example, once the highly compressed air leaves the injector system and enters the patient vasculature system which is at significantly lower pressures (e.g., approximately 1 atm), the volume of the air bubble may increase significantly due to the reduced pressure. Thus, injection of even small volumes of air at the high pressures used for CV procedures must be strenuously avoided. Additionally, because of the high pressures used, the speed of the fluid flowing through the fluid path, the air compressibility, and/or the volume compliance of the system and its components, air may potentially still be injected into the patient even if actuation of the syringe piston is halted. 
     SUMMARY OF THE DISCLOSURE 
     In view of the foregoing, there exists a need for devices, systems, and methods for preventing air from being delivered to a patient during an injection procedure. Embodiments of the present disclosure are directed to a fluid injector system including at least one syringe configured for injecting medical fluid and a fluid path assembly in fluid communication with the at least one syringe, the fluid path assembly including at least one air detection region. The fluid injector system further includes an air detector configured to detect one or more air bubbles in a fluid path associated with the air detection region, at least one shutoff valve at a distal end of the fluid path assembly, and at least one processor programmed or configured to actuate the at least one shutoff valve in response to the air detector detecting the one or more air bubbles in the fluid path associated with the air detection region to prevent fluid flow out of the fluid path assembly. The fluid path assembly has a length greater than a distance that an air bubble can travel or expand during an actuation time of the at least one shutoff valve. 
     In some embodiments, the actuation time of the at least one shutoff valve is a time interval between a time at which the air bubble is detected in the air detection region and a time at which the at least one shutoff valve reaches a stop position. 
     In some embodiments, the fluid path assembly includes a fluid path length having a path length of between approximately 1000 millimeters and approximately 1400 millimeters. 
     In some embodiments, the fluid injector system further includes a fluid path tubing element including a plurality of tubes arranged in a zig-zag configuration and connected to one another in series. In some embodiments, the plurality of tubes are parallel to one another. 
     In some embodiments, the plurality of tubes are connected to one another by a plurality of associated u-turn elements. In some embodiments, each of the plurality of associated u-turn elements defines a 180° turn to divert fluid flow from one of the plurality of tubes to another of the plurality of tubes. In some embodiments, the plurality of u-turn elements are formed in a pair of end caps, and the pair of end caps are joined to open ends of the plurality of tubes to form a fluid path between an inlet port and an outlet port 
     In some embodiments, the air detection region is associated with the inlet port of the fluid path tubing element. 
     In some embodiments, a total fluid path length of the fluid path tubing element is between approximately 1000 millimeters and approximately 1400 millimeters. 
     In some embodiments, the fluid injector system further includes a fluid path tubing element including a tortuous path. 
     In some embodiments, the fluid path tubing element includes a housing having a plurality of baffles to disrupt laminar flow of fluid though the housing. 
     In some embodiments, the housing includes a widened portion having an increased cross-sectional are configured to create a fluid pressure drop within the widened portion. 
     In some embodiments, the plurality of baffles extend across a centerline of the housing such that fluid is forced to flow around the plurality of baffles. 
     In some embodiments, the plurality of baffles includes at least one baffle extending from a first inner surface into a fluid path of the housing, and at least one baffle extending from a second inner surface into the fluid path of the housing and opposite of the first inner surface. The at least one baffle extending from the second inner surface of the housing is offset in a longitudinal direction from the at least one baffle extending from the first inner surface of the housing. In some embodiments, the plurality of baffles are angled to include a plurality of corners. 
     In some embodiments, the fluid path tubing element is movable between a priming position and an injection position. In the priming position, an outlet of the fluid path tubing element is oriented substantially upward such that air bubbles within the fluid path flow towards the outlet due, at least in part, to buoyancy. In the injection position, the outlet of the fluid path tubing element is oriented downward such that air bubbles within the fluid path flow away from the outlet due, at least in part, to buoyancy. 
     In some embodiments, the at least one processor is programmed or configured to move the fluid path tubing element between the priming position and the injection position. 
     Other embodiments of the present disclosure are directed to a fluid path tubing element for a fluid injector system. The fluid path tubing element includes an inlet port configured for fluid communication with at least one syringe, an outlet port configured for fluid communication with a valve, a tubing portion having a plurality of individual parallel tubes, and a plurality of u-turn elements connecting the plurality of individual parallel tubes in series in a zig-zag configuration. In some embodiments, each of the plurality of associated u-turn elements defines a 180° turn to divert fluid flow from one of the plurality of tubes to another of the plurality of tubes. 
     In some embodiments, the plurality of u-turn elements are formed in a pair of end caps, and the pair of end caps are joined to open ends of the plurality of individual parallel tubes of the tubing portion to form a fluid path between the inlet port and the outlet port. 
     In some embodiments, the total length of the fluid path tubing element is greater than a distance that an air bubble can travel or expand during an actuation time of the valve. 
     In some embodiments, the inlet port includes an air detection region configured for operative communication with an air detector configured to detect one or more air bubbles in the air detection region. 
     In some embodiments, a total fluid path length of the fluid path tubing element is between approximately 1000 millimeters and approximately 1400 millimeters. 
     Other embodiments of the present disclosure are directed to a fluid path tubing element for a fluid injector system. The fluid path tubing element includes a housing having an inlet port configured for fluid communication with at least one fluid injector and an outlet port configured for fluid communication with a valve, and a plurality of baffles to disrupt laminar flow of fluid though the housing. The plurality of baffles extend across a centerline of the housing such that fluid is forced to flow around the plurality of baffles. 
     In some embodiments, the housing includes a widened portion having an increased cross-sectional area configured to create a fluid pressure drop within the widened portion. 
     In some embodiments, the plurality of baffles includes at least one baffle extending from a first inner surface into a fluid path of the housing, and at least one baffle extending from a second inner surface into the housing of the housing and opposite the first inner surface. The at least one baffle extending from the second inner surface of the housing is offset in a longitudinal direction from the at least one baffle extending from the first inner surface of the housing. In some embodiments, the plurality of baffles are angled to include a plurality of corners. In some embodiments, the plurality of baffles are directional. 
     In some embodiments, the inlet port includes an air detection region configured for operative communication with an air detector configured to detect one or more air bubbles in the air detection region. 
     In some embodiments, a total fluid path length of the fluid path tubing element is between approximately 1000 millimeters and approximately 1400 millimeters. 
     Further aspects or examples of the present disclosure are described in the following numbered clauses: 
     Clause 1. A fluid injector system comprising: at least one syringe configured for injecting medical fluid; a fluid path assembly in fluid communication with the at least one syringe, the fluid path assembly comprising at least one air detection region; an air detector configured to detect one or more air bubbles in a fluid path associated with the air detection region; at least one shutoff valve at a distal end of the fluid path assembly; and at least one processor programmed or configured to actuate the at least one shutoff valve in response to the air detector detecting the one or more air bubbles in the fluid path associated with the air detection region to prevent fluid flow out of the fluid path assembly, wherein the fluid path assembly has a length greater than a distance that an air bubble can travel or expand during an actuation time of the at least one shutoff valve. 
     Clause 2. The fluid injector system of clause 1, wherein the actuation time of the at least one shutoff valve is a time interval between a time at which the air bubble is detected in the air detection region and a time at which the at least one shutoff valve reaches a stop position. 
     Clause 3. The fluid injector system of clause 1 or 2, wherein the fluid path assembly comprises a fluid path length having a path length of between approximately 1000 millimeters and approximately 1400 millimeters. 
     Clause 4. The fluid injector system of any of clauses 1 to 3, further comprising a fluid path tubing element comprising a plurality of tubes arranged in a zig-zag configuration and connected to one another in series. 
     Clause 5. The fluid injector system of any of clauses 1 to 4, wherein the plurality of tubes are parallel to one another. 
     Clause 6. The fluid injector system of any of clauses 1 to 5, wherein the plurality of tubes are connected to one another by a plurality of associated u-turn elements. 
     Clause 7. The fluid injector system of any of clauses 1 to 6, wherein each of the plurality of associated u-turn elements defines a 180° turn to divert fluid flow from one of the plurality of tubes to another of the plurality of tubes. 
     Clause 8. The fluid injector system of any of clauses 1 to 7, wherein the plurality of u-turn elements are formed in a pair of end caps, and wherein the pair of end caps are joined to open ends of the plurality of tubes to form a fluid path between an inlet port and an outlet port 
     Clause 9. The fluid injector system of any of clauses 1 to 8, wherein the air detection region is associated with the inlet port of the fluid path tubing element. 
     Clause 10. The fluid injector system of any of clauses 1 to 9, wherein a total fluid path length of the fluid path tubing element is between approximately 1000 millimeters and approximately 1400 millimeters. 
     Clause 11. The fluid injector system of any of clauses 1 to 10, further comprising a fluid path tubing element comprising a tortuous path. 
     Clause 12. The fluid injector system of any of clauses 1 to 11, wherein the fluid path tubing element comprises a housing having a plurality of baffles to disrupt laminar flow of fluid though the housing. 
     Clause 13. The fluid injector system of any of clauses 1 to 12, wherein the housing comprises a widened portion having an increased cross-sectional are configured to create a fluid pressure drop within the widened portion. 
     Clause 14. The fluid injector system of any of clauses 1 to 13, wherein the plurality of baffles extend across a centerline of the housing such that fluid is forced to flow around the plurality of baffles. 
     Clause 15. The fluid injector system of any of clauses 1 to 14, wherein the plurality of baffles comprises: at least one baffle extending from a first inner surface into a fluid path of the housing; and at least one baffle extending from a second inner surface into the fluid path of the housing and opposite of the first inner surface, wherein the at least one baffle extending from the second inner surface of the housing is offset in a longitudinal direction from the at least one baffle extending from the first inner surface of the housing. 
     Clause 16. The fluid injector system of any of clauses 1 to 15, wherein the plurality of baffles are angled to include a plurality of corners. 
     Clause 17. The fluid injector system of any of clauses 1 to 16, wherein the fluid path tubing element is movable between a priming position and an injection position, wherein, in the priming position, an outlet of the fluid path tubing element is oriented substantially upward such that air bubbles within the fluid path flow towards the outlet due, at least in part, to buoyancy, and wherein, in the injection position, the outlet of the fluid path tubing element is oriented downward such that air bubbles within the fluid path flow away from the outlet due, at least in part, to buoyancy. 
     Clause 18. The fluid injector system of any of clauses 1 to 17, wherein the at least one processor is programmed or configured to move the fluid path tubing element between the priming position and the injection position. 
     Clause 19. A fluid path tubing element for a fluid injector system, the fluid path tubing element comprising: an inlet port configured for fluid communication with at least one syringe; an outlet port configured for fluid communication with a valve; a tubing portion having a plurality of individual parallel tubes; and a plurality of u-turn elements connecting the plurality of individual parallel tubes in series in a zig-zag configuration. 
     Clause 20. The fluid injector system of clause 19, wherein each of the plurality of associated u-turn elements defines a 180° turn to divert fluid flow from one of the plurality of tubes to another of the plurality of tubes. 
     Clause 21. The fluid path tubing element of clause 19 or 20, wherein the plurality of u-turn elements are formed in a pair of end caps, and wherein the pair of end caps are joined to open ends of the plurality of individual parallel tubes of the tubing portion to form a fluid path between the inlet port and the outlet port. 
     Clause 22. The fluid path tubing element of any of clauses 19 to 21, wherein the total length of the fluid path tubing element is greater than a distance that an air bubble can travel or expand during an actuation time of the valve. 
     Clause 23. The fluid path tubing element of any of clauses 19 to 22, wherein the inlet port comprises an air detection region configured for operative communication with an air detector configured to detect one or more air bubbles in the air detection region. 
     Clause 24. The fluid path tubing element of any of clauses 19 to 23, wherein a total fluid path length of the fluid path tubing element is between approximately 1000 millimeters and approximately 1400 millimeters. 
     Clause 25. A fluid path tubing element for a fluid injector system, the fluid path tubing element comprising: a housing having an inlet port configured for fluid communication with at least one fluid injector and an outlet port configured for fluid communication with a valve; and a plurality of baffles to disrupt laminar flow of fluid though the housing, wherein the plurality of baffles extend across a centerline of the housing such that fluid is forced to flow around the plurality of baffles. 
     Clause 26. The fluid path tubing element of clause 25, wherein the housing comprises a widened portion having an increased cross-sectional area configured to create a fluid pressure drop within the widened portion. 
     Clause 27. The fluid path tubing element of clause 25 or 26, wherein the plurality of baffles comprises: at least one baffle extending from a first inner surface into a fluid path of the housing; and at least one baffle extending from the a second inner surface into the housing of the housing and opposite the first inner surface, wherein the at least one baffle extending from the second inner surface of the housing is offset in a longitudinal direction from the at least one baffle extending from the first inner surface of the housing. 
     Clause 28. The fluid path tubing element of any of clauses 25 to 27, wherein the plurality of baffles are angled to include a plurality of corners. 
     Clause 29. The fluid path element tubing element of any of clauses 25 to 28, wherein the plurality of baffles are directional. 
     Clause 30. The fluid path tubing element of any of clauses 25 to 29, wherein the inlet port comprises an air detection region configured for operative communication with an air detector configured to detect one or more air bubbles in the air detection region. 
     Clause 31. The fluid path tubing element of any of clauses 25 to 30, wherein a total fluid path length of the fluid path tubing element is between approximately 1000 millimeters and approximately 1400 millimeters. 
     Further details and advantages of the various examples described in detail herein will become clear upon reviewing the following detailed description of the various examples in conjunction with the accompanying drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a perspective view of a fluid injector system according to an embodiment of the present disclosure; 
         FIG.  1 B  is a perspective view of a fluid injector system according to an embodiment of the present disclosure; 
         FIG.  2    is a schematic view of a fluid injector system in accordance with an embodiment of the present disclosure; 
         FIG.  3    is a perspective view of a fluid path assembly for use with a fluid injector system in accordance with an embodiment of the present disclosure; 
         FIG.  4    is a perspective view of a fluid path assembly for use with a fluid injector system in accordance with an embodiment of the present disclosure; 
         FIG.  5    is a perspective view of a remote automated shutoff valve for use with fluid path assembly of a fluid injector system in accordance with an embodiment of the present disclosure; 
         FIG.  6    is a perspective view of various single- or multi-use components for a fluid injector system according to an embodiment of the present disclosure; 
         FIG.  7    is a perspective view of a fluid path tubing element of the fluid path assembly of  FIG.  6    according to an embodiment of the present disclosure; 
         FIG.  8    is an exploded perspective view of the fluid path tubing element of  FIG.  7   ; 
         FIG.  9    is an end view of the fluid path tubing element of  FIG.  7   ; 
         FIG.  10    is a cross-sectional side view of the fluid path tubing element of  FIG.  7    along line A—A of  FIG.  9   ; 
         FIG.  11    is a side perspective view of a fluid path tubing element according to another embodiment of the present disclosure; 
         FIG.  12    is a cross-sectional side view of the fluid path tubing element of  FIG.  11   ; 
         FIG.  13    is a side perspective view of a fluid path tubing element according to another embodiment of the present disclosure; 
         FIG.  14    is a cross-sectional side view of the fluid path tubing element of  FIG.  13   ; 
         FIG.  15    is a cross-sectional side view of a fluid path tubing element according to another embodiment of the present disclosure; and 
     
    
    
     Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, the present disclosure is generally directed to an in-line air bubble suspension apparatus for use with an angiography injector system. 
     DETAILED DESCRIPTION 
     For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal”, and derivatives thereof shall relate to the disclosure as it is oriented in the drawing figures. Spatial or directional terms, such as “left”, “right”, “inner”, “outer”, “above”, “below”, and the like, are not to be considered as limiting as the invention can assume various alternative orientations. 
     As used herein, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. 
     All numbers used in the specification and claims are to be understood as being modified in all instances by the term “about”. The terms “approximately”, “about”, and “substantially” mean a range of plus or minus ten percent of the stated value. 
     As used herein, the term “at least one of” is synonymous with “one or more of”. For example, the phrase “at least one of A, B, and C” means any one of A, B, and C, or any combination of any two or more of A, B, and C. For example, “at least one of A, B, and C” includes one or more of A alone; or one or more B alone; or one or more of C alone; or one or more of A and one or more of B; or one or more of A and one or more of C; or one or more of B and one or more of C; or one or more of all of A, B, and C. Similarly, as used herein, the term “at least two of” is synonymous with “two or more of”. For example, the phrase “at least two of D, E, and F” means any combination of any two or more of D, E, and F. For example, “at least two of D, E, and F” includes one or more of D and one or more of E; or one or more of D and one or more of F; or one or more of E and one or more of F; or one or more of all of D, E, and F. 
     It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary examples of the disclosure. Hence, specific dimensions and other physical characteristics related to the examples disclosed herein are not to be considered as limiting. 
     When used in relation to a component of a fluid delivery system such as a fluid reservoir, a syringe, or a fluid line, the term “distal” refers to a portion of said component nearest to a patient. When used in relation to a component of a injector system such as a fluid reservoir, a syringe, or a fluid line, the term “proximal” refers to a portion of said component nearest to the injector of the injector system (i.e. the portion of said component farthest from the patient). When used in relation to a component of a fluid delivery system such as a fluid reservoir, a syringe, or a fluid line, the term “upstream” refers to a direction away from the patient and towards the injector of the injector system. For example, if a first component is referred to as being “upstream” of a second component, the first component is located nearer to the injector than the second component is to the injector. When used in relation to a component of a fluid delivery system such as a fluid reservoir, a syringe, or a fluid line, the term “downstream” refers to a direction towards the patient and away from the injector of the fluid delivery system. For example, if a first component is referred to as being “downstream” of a second component, the first component is located nearer to the patient than the second component is to the patient. 
     As used herein, the terms “capacitance” and “impedance” are used interchangeably to refer to a volumetric expansion of injector components, such as fluid reservoirs, syringes, fluid lines, and/or other components of a fluid delivery system as a result of pressurized fluids with such components and/or uptake of mechanical slack by force applied to components. Capacitance and impedance may be due to high injection pressures, which may be on the order of 1200 psi in some angiographic procedures, and may result in a volume of fluid held within a portion of a component in excess of the desired quantity selected for the injection procedure or the resting volume of the component. Additionally, capacitance of various components can, if not properly accounted for, adversely affect the accuracy of pressure sensors of the injector system because the volumetric expansion of components can cause an artificial drop in measured pressure of those components. 
     The terms “first”, “second”, and the like are not intended to refer to any particular order or chronology, but refer to different conditions, properties, or elements. 
     All documents referred to herein are “incorporated by reference” in their entirety. 
     The term “at least” is synonymous with “greater than or equal to.” The term “not greater than” is synonymous with “less than or equal to.” 
     It is to be understood that the disclosure may assume alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary aspects of the disclosure. Hence, specific dimensions and other physical characteristics related to the examples disclosed herein are not to be considered as limiting. 
     While the systems and apparatuses described herein are with reference to an angiography (CV) injection system, other pressurized injection protocols, such as computed tomography (CT) and magnetic resonance imaging (MRI) may also incorporate the various embodiments described herein for preventing injection of air. 
     Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, the present disclosure is generally directed to fluid injector systems and fluid path assemblies for detecting and preventing the delivery of one or more air bubbles that may inadvertently occur during an injection procedure. Injection of air to the patient&#39;s cardiovascular system is prevented by closing the fluid path assembly and ensuring that the air has insufficient time to reach the closure point in the time required to close the fluid path assembly. The length and/or volume of the fluid path assembly, including various fluid path tubing elements thereof, may be selected based on injection and apparatus parameters to prevent fluid communication between syringes of the fluid injector and a patient tube set downstream of an automated remote shutoff valve, such injection and apparatus parameters including, for example: flow rate, fluid viscosity, ID of tubing, response time of a processor upon detection of one or more air bubbles, and time necessary for the processor to communicate to and actuate a downstream automated remote shutoff valve to a stop position. 
     Referring first to  FIG.  1 A , an embodiment of a dual syringe angiography injector system  1000  is illustrated. The angiography injector system  1000  is configured for injection of two medical fluids through a first fluid path  110 A for a medical fluid, such as an imaging contrast media for an angiography injection procedure, and a second fluid path  110 B for a flushing fluid, such as saline or Ringer&#39;s lactate. The dual syringe angiography injector system  1000  may include an injector housing  12  having two syringe ports  15  configured to engage two syringes  10 A,  10 B. In some embodiments, the syringes  10 A,  10 B may be retained within corresponding pressure jackets for example to prevent pressure-induced swelling and potential bursting of the syringes  10 A,  10 B. 
     The injector housing  12  may further include at least one graphical user interface (GUI)  11  through which an operator can view and control the status of an injection procedure. The GUI  11  may be in operative communication with a controller  900  (see  FIG.  2   ) which sends and receives commands to and from the GUI  11 . 
     The dual syringe angiography injector system  1000  may further include at least one upstream air detector  200  for detecting one or more air bubbles within an air detection tubing region  150  of the first fluid path  110 A and the second fluid path  110 B. The air detection tubing region  150  may for example, be associated with a proximal portion of the first fluid path  110 A and the second fluid path  110 B. In some embodiments, the at least one air detector  200  may be a single module having at least one sensor operatively associated with each of the first fluid path  110 A and the second fluid path  110 B. In some embodiments, the at least one air detector  200  may include at least two distinct modules, each module operatively associated with one of the first fluid path  110 A and the second fluid path  110 B. The at least one air detector  200  may be in operative communication with the controller  900  (see  FIG.  2   ) such that the at least one air detector  200  may send and the controller  900  may receive signals from the at least one air detector  200  indicating the detection of the presence of one or more air bubbles in one or both of the first fluid path  110 A and/or the second fluid path  110 B. The at least one air detector  200  may include an ultrasonic sensor, and optical sensor, or the like, configured to detect the one or more air bubbles within the fluid path. 
     Referring now to  FIG.  1 B , an embodiment of a dual syringe angiography injector system  2000  is illustrated for multi-patient use. The angiography injector system  1000  is configured for injection of two medical fluids through a first fluid path  210 A for a medical fluid, such as an imaging contrast media for an angiography injection procedure, and a second fluid path  210 B for a flushing fluid, such as saline or Ringer&#39;s lactate. The dual syringe angiography injector system  1000  may include an injector housing  12  having two syringe ports  15  configured to engage two syringes  10 A,  10 B. In some embodiments, the syringes  10 A,  10 B may be retained within corresponding pressure jackets, for example to prevent pressure-induced swelling and potential bursting of the syringes  10 A,  10 B. 
     The angiography injector system  2000  may further include bulk fluid containers  19 A and  19 B for filling and refilling the respective syringes  10 A,  10 B with imaging contrast media and flushing fluid, respectively, through bulk fluid paths  216 A and  216 B and bulk fluid valves  215 A and  215 B, respectively, during multiple patient fluid injection procedures. 
     The injector housing  12  may further include at least one graphical user interface (GUI)  11  through which an operator can view and control the status of an injection procedure. The GUI  11  may be in operative communication with a controller  900  (see  FIG.  2   ) which sends and receives commands to and from the GUI  11 . 
     The dual syringe angiography injector system  1000  may further include at least one air detector  200  for detecting one or air bubbles within an air detection tubing region  150  of the first fluid path  210 A and the second fluid path  210 B. The air detection tubing region  150  may for example, be associated with a proximal portion of the first fluid path  210 A and the second fluid path  210 B. In some embodiments, the at least one air detector  200  may be a single module having at least one sensor operatively associated with each of the first fluid path  210 A and the second fluid path  210 B. In some embodiments, the at least one air detector  200  may include at least two distinct modules, each module operatively associated with one of the first fluid path  210 A and the second fluid path  210 B. The at least one air detector  200  may be in operative communication with the controller  900  ( FIG.  2   ) such that the at least one air detector  200  may send and the controller  900  may receive signals from the at least one air detector  200  indicating detection of the presence of one or more air bubbles in one or both of the first fluid path  210 A and/or the second fluid path  210 B. The at least one air detector  200  may include an ultrasonic sensor, and optical sensor, or the like configured to detect the one or more air bubbles within the fluid path. 
     Referring to  FIG.  2   , a schematic diagram of the injection system  2000  shown in  FIG.  1 B  is illustrated. The injector system  2000  includes a piston  13  associated with each of the syringes  10 A,  10 B that drives a plunger  14  within a barrel of each syringe  10 . The controller  900  is operatively associated with the pistons  13  to reciprocatively move the plungers  14  within the syringes  10 A,  10 B and thereby execute an injection procedure. In particular, the controller  900  may include at least one processor programmed or configured to actuate the pistons  13  and various other components of the injector system  1000  as described herein, to take in and deliver the medical fluids according to a programmed protocol for an injection procedure. The controller  900  may include computer readable media, such as memory, on which one or more injection protocols may be stored for execution by the at least one processor. 
     The controller  900  may be programmed or configured to execute a filling operation during which the piston  13  associated with each syringe  10  A,  10 B is withdrawn toward a proximal end of the syringe  10  A,  10 B to draw medical fluid F (e.g. imaging contrast media and flushing fluid) into the syringe  10 A,  10 B from the bulk fluid containers  19 A,  19 B. During such filling operation, the controller  900  may be programmed or configured to selectively actuate the bulk fluid valves  215 A and  215 B to establish fluid communication between the respective syringes  10 A,  10 B and the bulk fluid container  19 A,  19 B via the bulk fluid paths  216 A and  216 B to control filling of the syringe with the appropriate medical fluid. Upon completion of the filing operation, and optionally a priming operation to remove any air from the syringe (for example by priming any such air back into the bulk fluid container or through a priming tube), the controller  900  may be programmed or configured to selectively actuate the bulk fluid valves  215 A and  215 B to block fluid communication between the respective syringes  10 A,  10 B and the bulk fluid container  19 A,  19 B via the bulk fluid paths  216 A and  216 B. 
     After the filling operation and priming operation, the controller  900  may be programmed or configured to execute a delivery operation during which the piston  13  associated with one or both of the syringes  10 A,  10 B is moved toward a distal end of the syringe to inject medical fluid F into the first fluid path  110 A,  210 A and the second fluid path  110 B,  210 B. The controller  900  may be programmed or configured to selectively actuate the bulk fluid valves  215 A and  215 B to establish fluid communication between the syringes  10 A,  10 B and the patient, via the fluid paths  110 A,  110 B,  210 A,  210 B. The first fluid path  110 A,  210 A and the second fluid path  110 B,  210 B ultimately merge into a patient fluid line  395 ,  495  in fluid communication with the vasculature of the patient. According to various embodiments, the first fluid path  110 A,  210 A and the second fluid path  110 B,  210 B may merge at a fluid mixing connector that provides turbulent mixing of the first fluid and the second fluid, such as a fluid mixing connector described in International PCT Application Nos. PCT/US2021/019507 and PCT/US2014/026324, the disclosures of which are incorporated herein by reference. 
     The controller  900  may be in operative communication with the at least one air detector  200  such that the controller  900  may stop actuation of the pistons  13  in response to the air detector  200  detecting the presence of one or more air bubbles in at least one of the first fluid path  110 A,  210 A and/or the second fluid path  110 B,  210 B. The controller  900  may further be in operative communication with at least one downstream automated remote shutoff valve  390 ,  490 , such that the controller  900  may actuate the at least one remote shutoff valve  390 ,  490  to stop fluid flow and flow of the one or more air bubbles through the at least one remote shutoff valve  390 ,  490  and into the patient vascular system. The at least one remote shutoff valve  390 ,  490  may be actuated by the controller  900  between various positions such a delivery position in which medical fluid may flow to the patient, a stop position in which fluid flow to the patient is prevented, and a hemodynamic monitoring position in which the patient&#39;s vasculature is in fluid communication with a pressure transducer and isolated from syringes  10 A,  10 B. 
     During a normal delivery operation, the controller  900  may be programmed or configured to move the remote shutoff valve  390 ,  490 ,  590  to a delivery position to establish fluid communication between the patient and the fluid paths  110 A,  110 B,  210 A,  210 B. The controller  900  may be programmed or configured to transition the remote shutoff valve  390 ,  490  to a stop position in response to air being detected by the at least one air detector  200 . In the stop position, the remote shutoff valve  390 ,  490  fluidly isolates the patient from the fluid paths  110 A,  110 B,  210 A,  210 B, thereby preventing air from being injected into the patient. Further details of the remote shutoff valve  390 ,  490  will be described in greater detail herein, for example with reference to  FIGS.  3 - 5   . 
     With continued reference to  FIG.  2   , in some embodiments, each of the first fluid path  110 A,  210 A and the second fluid path  110 B,  210 B may include a fluid path tubing element  230 . Each fluid path tubing element  230  may be in the form a zig-zag tubing element (as described in greater detail herein with reference to  FIGS.  6 - 14   ) having a configuration to lengthen the fluid path distance between the at least one air detector  200  and the remote shutoff valve  390 ,  490  and increase fluid volume associated therewith. In some embodiments, the fluid path tubing element  230  may include a torturous path configured to at least temporarily trap or delay one or more air bubbles within the fluid path tubing element  230 , for example by temporarily adhering to an inner wall surface or corner of the fluid path tubing element  230 . In certain embodiments, the fluid path tubing element  230  may further include one or more widened sections having a greater cross-sectional area than a preceding section of the fluid path. The one or more widened sections may be configured to cause a fluid pressure drop within the fluid flow and to slow flow of the fluid through the widened sections, causing the one or more air bubbles to slow and/or temporarily adhere to a inner wall of the wider section of the tubing element. Various embodiments of the fluid path tubing element  230  are described in greater detail herein with reference to  FIGS.  6 - 14   . It is to be understood that not all embodiments of the fluid injector system  1000 ,  2000  include the fluid path tubing elements  230 . For example, the embodiments shown in  FIGS.  3  and  4    do not include the fluid path tubing elements  230 . 
     In the embodiments of the fluid injector systems  1000 ,  2000  described herein, the at least one syringe  10 A,  10 B may be oriented in any manner such as upright, downright, or positioned at any degree angle. In certain embodiments the fluid injector system  1000 ,  2000  may be pivotable between one or more positions, for example, the fluid injector system  1000 ,  2000  may be positioned in an upright position during a filling operation and pivoted to a downward angled position during a delivery operation The injector system  1000 ,  2000  may be a multi-syringe injector, as shown, wherein several syringes  10 A,  10 B may be oriented side-by-side or in another spatial relationship and are separately actuated by respective pistons associated with the injector system  1000 ,  2000 . However, it should be appreciated that the various embodiments described herein for preventing air injection to a patient are equally applicable to a single-syringe injector system. 
     Further details and examples of suitable nonlimiting powered injector systems, including syringes, controllers, and air detectors, are described in U.S. Pat. Nos. 5,383,858; 7,553,294; 7,666,169; 8,945,051; 10,022,493; and 10,507,319, the disclosures of which are hereby incorporated by reference in their entireties. While the fluid path elements described herein are illustrated in combination with a fluid injector system including syringes, other fluid delivery mechanisms, such as a pump, for example one or more peristaltic pumps, may be substituted for one or both of the syringes of the fluid delivery systems. 
     Referring now to  FIGS.  3  and  4   , various embodiments of fluid path assemblies  300 ,  400  for use with the injector systems  1000 ,  2000  (see  FIGS.  1 A- 1 B and  2   ) are illustrated. The fluid paths  110 A,  110 B,  210 A,  210 B shown in  FIGS.  1 A- 1 B and  2    may correspond to proximal sections of the fluid path assemblies  300 ,  400  according to certain embodiments. Likewise, the bulk fluid valves  215 A and  215 B of  FIGS.  1 B and  2    may correspond to various valves  315 A and  415 A of the fluid path assemblies  300 ,  400 . Referring first to  FIG.  3   , a single-patient fluid path assembly  300  is configured for attachment to one or more high-pressure syringes, such as the syringes  10 A,  10 B of the injector systems  1000 ,  2000  shown in  FIGS.  1 A- 1 B and  2   , by proximal connectors  305 . The fluid path assembly  300  includes a length of tubing  360 , which may correspond to the first fluid path  110 A and the second fluid path  110 B. A proximal section of the length of tubing  360  may include an air bubble sensing region  350  in operative communication with the at least one air detector  200  (see  FIGS.  1 A- 1 B and  2   ). As such, the at least one air detector  200  can detect the presence of one or more air bubbles in the fluid path  300  as the fluid passes through the air bubble sensing region  350  during an injection procedure. The fluid path assembly  300  may further include three-way stopcocks  315 A to provide fluid communication between bulk fluid containers  19 A,  19 B (see  FIG.  2   ) and the syringes  10  by way of bulk fluid paths  316 . Other stopcocks  315 B may be included in the fluid path assembly  300  to control fluid flow, pressure, and backflow, as described herein. In various embodiments, the fluid path assembly  300  may include a fluid mixing connector element  387  to merge fluid flow from each of the syringes  10 . The fluid mixing connector element  387  may include a mixing element such as described in International PCT Application Nos. PCT/US2021/019507 and PCT/US2014/026324. 
     Referring still to  FIG.  3   , the automated remote shutoff valve  390  may be located proximal to or distal to the fluid mixing connector element  387 . According to various embodiments where the automated remote shutoff valve  390  is be located distal to the fluid mixing connector element  387 , the automated remote shutoff valve  390  may include an input port  391  in selective fluid communication with the fluid mixing connector element  387 , a patient port  392  in selective fluid communication with patient delivery tubing  395 , and a hemodynamic sensor port  393  in selective fluid communication with a hemodynamic monitor  380 , such as a pressure transducer, through hemodynamic fluid path  383 . As described herein with reference to  FIG.  2   , the remote shutoff valve  390  may be moved between the delivery position, the stop position, and the hemodynamic monitoring position. 
     In the delivery position, the remote shutoff valve  390  provides fluid communication between the input port  391  and the patient port  392 . As such, fluid communication between the at least one syringe  10 A,  10 B and the patient through the fluid path assembly  300 , including the length of tubing  360  and the patient delivery tubing  395 , permits fluid flow from the at least one syringe  10 A,  10 B, through the fluid path assembly  300 , through the automated remote shutoff valve  390 , and into the patient delivery tubing  395 . The fluid path assembly  300  may remain in the fluid delivery position until the total desired volume of medical fluid is delivered to the patient, at which time the controller  900  may cease actuation of the plungers  13  to halt fluid flow and also actuate the remote shutoff valve  390  to the closed position to prevent unwanted fluid flow from the system to the patient by loss of capacitance volume (e.g., relaxation of the expanded volume of fluid path components) of the fluid path assembly  300  in the absence of a pressurizing force. Further, the fluid path assembly  300  may remain in the fluid delivery position until at least one air bubble is detected in the air bubble sensing region  350 , at which time the controller  900  may move the remote shutoff valve  390  to the stop position as described herein. In some embodiments, controller  900  may additionally close one or more of the three-way valves  315 A and/or  315 B once the desired volume of fluid has been delivered to the patient in order to prevent over-delivery due to capacitance and mechanical slack in the injector system  1000 ,  2000 . 
     In the hemodynamic monitoring position, the remote shutoff valve  390  provides fluid communication between the hemodynamic sensor port  393  and the patient port  392 . In the stop position, the remote shutoff valve  390  isolates the input port  391  from the patient port  392 , such that there no fluid communication between the input port  391  and the patient port  392 . In some embodiments, the hemodynamic monitoring position may also act as the stop position because there is no fluid communication between the input port  391  and the patient port  392  in the hemodynamic monitoring position. 
     As described herein, a typical angiographic injection procedure may experience fluid pressures of up to, for example, 1200 psi during delivery of fluid to the patient. As pressure sensors suitable for use as the hemodynamic monitor  380  may be damaged by such high pressures, the hemodynamic sensor port  393  may be isolated from the inlet port  391  and the patient port  392  in the hemodynamic monitoring position of the remote shutoff valve  390 . In some embodiments, the hemodynamic position of the remote shutoff valve  390  may be used during a low-pressure injection phase or a monitoring phase of an injection protocol, such as described in PCT International Publication No. WO 2018/218132, the disclosure of which is hereby incorporated by reference in their entireties. 
     Suitable structures for the automated remote shutoff valve  390  include, for example stopcocks, pinch valves, high crack pressure valves, check valves, solenoid valves, spool valves, gate valves, knife valves, and the like, including combinations of one or more of these valves. In some embodiments, the automated remote shutoff valve  390  may be a three-way high-pressure stopcock including a rotatable inner valve member. 
     In some embodiments, an intermediate stop position of the fluid path assembly  300  may be used, for example by moving one of the three-way valves  315 A or  315 B to a closed position to prevent pressurized backflow of fluid from a pressurized second syringe  10 B into the fluid path assembly  300 , a bulk fluid source  19 A,  19 B, and/or a first syringe  10 A. In certain embodiments, the intermediate stop position may allow pre-pressurization of a medical fluid in one or more of syringes  10 A,  10 B prior to delivery of fluid from the fluid path assembly  300  during an injection procedure. This may have the advantage of taking up capacitance in the syringe and other upstream fluid path components and/or taking up mechanical slack in the injector system to provide a more accurate fluid delivery volume. In other embodiments, pre-pressurization of a medical fluid in syringe  10  may provide smoother pressure/flow transitions when switching between injection of a more viscous medical fluid and a less viscous medical fluid, such as contrast and saline, respectively. Examples of injection protocols using pre-pressurization to prevent fluid flow spikes during fluid transitions are described in International PCT Publication Nos. WO 2019/046260 and WO 2019/046259, the disclosures of which are incorporated herein by this reference. In other embodiments, the intermediate stop position may allow for detection of air within the syringe system by pressurization of the syringe contents prior to the injection protocol, as described in International PCT Publication No. WO 2019/204605, the disclosure of which is incorporated herein by this reference. In other embodiments, the intermediate stop position may allow for vacuum coalescences and purging of air bubbles from the syringe system prior to the injection protocol, as described in International PCT Publication No. WO 2019/204617, the disclosure of which is incorporated herein by this reference. 
     Referring now to  FIG.  4   , a multi-patient fluid path assembly  400  is configured for attachment to one or more high-pressure syringes, such as the syringes  10 A,  10 B of the injector systems  1000  shown in  FIGS.  1 A- 1 B , by proximal connectors  405 . The fluid path assembly  400  includes a length of tubing  460 , which may correspond to the first fluid path  210 A and the second fluid path  210 B. A proximal section of the length of tubing  460  may include an air bubble sensing region  450  in operative communication with the at least one air detector  200  (see  FIGS.  1 A,  1 B, and  2   ). As such, the at least one air detector  200  can detect the presence of one or more air bubbles in the fluid path  400  as the fluid passes through the air bubble sensing region  450  during an injection procedure. The fluid path assembly  400  may further include three-way stopcocks  415 A to provide fluid communication between bulk fluid containers  19 A,  19 B (see  FIG.  2   ) and the syringes  10 A,  10 B by way of bulk fluid path  416 . Other stopcocks  415 B may be included in the fluid path assembly  400  to control fluid flow, pressure, and backflow, as described herein. In some embodiments, the fluid path assembly  400  may include a fluid mixing connector element  487  to merge fluid flow from each of the syringes  10  and ensure turbulent mixing of the two medical fluids. The fluid mixing connector element  487  may include a mixing element to such as described herein. 
     Referring still to  FIG.  4   , the automated remote shutoff valve  490  may be located proximal to or distal to the fluid mixing connector element  487 . According to various embodiments where the automated remote shutoff valve  490  is be located distal to the fluid mixing connector element  487 , the automated remote shutoff valve  490  may include an input port  491  in selective fluid communication with the fluid mixing connector element  487 , a patient port  492  in selective fluid communication with a patient fluid line  495 , and a hemodynamic sensor port  493  in selective fluid communication with a hemodynamic monitor  480 , such as a hemodynamic pressure transducer, through hemodynamic fluid path  483 . As described herein with reference to  FIG.  2   , the remote shutoff valve  490  may be moved between the delivery position, the stop position, and the hemodynamic monitoring position. 
     In the delivery position, the remote shutoff valve  490  provides fluid communication between the input port  491  and the patient port  492 . As such, fluid communication between the at least one syringe  10 A,  10 B and the patient through the fluid path assembly  400 , including the length of tubing  460  and the patient delivery tubing  495 , permits fluid flow from the interior volume of the at least one syringe  10 A,  10 B, through the fluid path assembly  400 , through the automated remote shutoff valve  490 , and into the patient delivery tubing  495 . The fluid path assembly  400  may remain in the fluid delivery position until the total desired volume of medical fluid is delivered to the patient, at which time the controller  900  may cease actuation of the plungers  13  to halt fluid flow and also actuate the remote shutoff valve  390  to the closed position to prevent unwanted fluid flow from the system to the patient by loss of capacitance volume (e.g., relaxation of the expanded volume of fluid path components) of the fluid path assembly  400  in the absence of a pressurizing force. Further, the fluid path assembly  400  may remain in the fluid delivery position until at least one air bubble is detected in the air bubble sensing region  450 , at which time the controller  900  may move the remote shutoff valve  490  to the stop position as described herein. In some embodiments, controller  900  may additionally close one or more of the three-way valves  415 A and/or  415 B once the desired volume of fluid has been delivered to the patient in order to prevent over-delivery due to capacitance and mechanical slack in the injector system  1000 ,  2000 . 
     In the hemodynamic monitoring position, the remote shutoff valve  490  provides fluid communication between the hemodynamic sensor port  493  and the patient port  492 . In the stop position, the remote shutoff valve  490  isolates the input port  491  from the patient port  492 , such that there no fluid communication between the input port  491  and the patient port  492 . In some embodiments, the hemodynamic monitoring position may also act as the stop position because there is no fluid communication between the input port  491  and the patient port  492  in the hemodynamic monitoring position. 
     As described herein, a typical angiographic injection procedure may experience fluid pressures of up to, for example, 1200 psi during delivery of fluid to the patient. As pressure sensors suitable for use as the hemodynamic monitor  480  may be damaged by such high pressures, the hemodynamic sensor port  493  may be isolated from the inlet port  491  and the patient port  492  in the hemodynamic monitoring position of the remote shutoff valve  490 . In some embodiments, the hemodynamic position of the remote shutoff valve  490  may be used during a low-pressure injection phase or a monitoring phase of an injection protocol, such as described in PCT International Publication No. WO 2018/218132. 
     Suitable structures for the automated remote shutoff valve  490  include, for example stopcocks, pinch valves, high crack pressure valves, check valves, solenoid valves, spool valves, gate valves, knife valves, and the like, including combinations or one or more of these valves. In some embodiments, the automated remote shutoff valve  490  may be a three-way high-pressure stopcock including a rotatable inner valve member. 
     In some embodiments, an intermediate stop position of the fluid path assembly  400  may be used, for example by moving one of the three-way valves  415 A or  415 B to a closed position to prevent pressurized backflow of fluid from a pressurized second syringe  10   b  into the fluid path assembly  400 , a bulk fluid source  19 A,  19 B, and/or a first syringe  10 A. In certain embodiments, the intermediate stop position may allow pre-pressurization of a medical fluid in one or more of syringes  10 A,  10 B prior to delivery of fluid from the fluid path assembly  400  during an injection procedure. This may have the advantage of taking up capacitance in the syringe and other upstream fluid path components and/or taking up mechanical slack in the injector system to provide a more accurate fluid delivery volume. In other embodiments, pre-pressurization of a medical fluid in syringe  10  may provide smoother pressure/flow transitions when switching between injection of a more viscous medical fluid and a less viscous medical fluid, such as contrast and saline, respectively. Examples of injection protocols using pre-pressurization to prevent fluid flow spikes during fluid transitions are described in International PCT Publication Nos. WO 2019/046260 and WO 2019/046259. In other embodiments, the intermediate stop position may allow for detection of air within the syringe system by pressurization of the syringe contents prior to the injection protocol, as described in International PCT Publication No. WO 2019/204605. In other embodiments, the intermediate stop position may allow for vacuum coalescences and purging of air bubbles from the syringe system prior to an injection protocol, as described in International PCT Publication No. WO 2019/204617. 
     Referring again to  FIGS.  1 - 4   , the fluid injector system  1000  according to various embodiments may take from 60 milliseconds to 90 milliseconds, for example in one embodiment approximately 80 milliseconds, between when one or more air bubble is sensed in the air detection region by the at least one air detector to when the shutoff valve actuator may actuate the remote shutoff valve from the delivery position to the stop position to stop a high pressure (e.g. 1200 psi) injection procedure via actuation of the remote shutoff valve  390 ,  490 . Total actuation time to stop such an injection procedure may include time detecting an air bubble by the air detector  200 ; time communicating from the air detector  200  to the controller  900  that an air bubble has been detected; time for the controller  900  actuating the remote shutoff valve  390 ,  490  to the stop position; and time until the patient line  395 ,  495  is fully isolated from the length of tubing  360 ,  460  to prevent continued fluid flow from one or more of rapid flow rate, compliance release, and/or bubble expansion from continuing into the patient&#39;s vasculature. At the high injection pressures typical of angiography injection procedures, an air bubble may move from 2.8 mL to 3.6 mL of the volume of the fluid path over the 70 milliseconds to 100 milliseconds between detection of the air bubble and valve closing/injection halting. For example, at approximately 1200 psi with conventional fluid path tubing diameters, an air bubble may travel a distance corresponding to 3.2 mL over 80 milliseconds at a flow rate of 30 mL/sec in a tubing with a 0.072 inch ID. The distance equivalence of 3.2 mL volume for such an embodiment may be approximately 1200 millimeters (or approximately 4 feet) of tubing length travelled during 80 milliseconds. Thus, even with a rapid response time, an air bubble may travel a significant distance after air detection and before system shutdown. Further, if pressurization of the fluid is halted or reduced, the reduction in fluid pressure may result in volume expansion of the air bubble, further increasing the distance the air volume can travel/occupy in the fluid path after a detection event. Thus, the volume of the tubing between the air detection region and remote shutoff valve  490  must be sufficient to allow the system adequate time to shut the fluid flow to the patient before the air bubble can pass the remote shutoff valve  490 . The volume of the tubing may be a factor of one or more of inner tubing diameter, length of tubing, pliability or rigidity of the tubing, presence of one or more baffles and combinations thereof associated with the tubing. 
     According to various embodiments, the length of tubing  360 ,  460  may provide a sufficient overall length and/or volume between the air bubble detection region  350 ,  450  and the automated remote shutoff valve  390 ,  490  to ensure that an air bubble detected in the air detection region  350 ,  450  cannot inadvertently be injected into the patient. That is, the internal volume of the length of tubing  360 ,  460  is such that an air bubble detected in the air detection region  350 ,  450  has insufficient time to flow past the automated remote shutoff valve  390 ,  490  in the actuation time required for the fluid path assembly  300 ,  400  to reach the stop position. In some embodiments, the overall length and volume of the length of tubing  360 ,  460  between the air bubble detection region  350 ,  450  and the inlet port  391 ,  491  may be a length calculated to prevent the air bubble from moving into the patient tubing  395 ,  495  before the remote shutoff valve  390 ,  490  can reach the stop position. The air bubble will thus become trapped in the length of tubing  360 ,  460  by moving the remote shutoff valve  390 ,  490  to the stop position and the injection procedure is halted. In certain embodiments, the fluid path assembly  300 ,  400  between the air bubble detection region  350 ,  450  and the automated remote shutoff valve  390 ,  490  may have a length of between approximately 1000 millimeters and approximately 1400 millimeters, and in some embodiments may be approximately 1200 millimeters (or from approximately 3.5 feet to approximately 4.5 feet, and in specific embodiments may be approximately 4 feet) in length to ensure that air bubbles cannot flow into the patient delivery tubing  395 ,  495 . The approximately 1000 millimeter to approximately 1400 millimeter length of tubing may be arranged in any manner between the air bubble detection region  350 ,  450  and the automated remote shutoff valve  390 ,  490 , for example, may be stretched lengthwise, draped, wrapped, looped, or coiled to reduce the footprint of the tubing length. 
     Referring now to  FIG.  5   , an embodiment of a remote valve assembly  500  including an automated remote shutoff valve  590  is illustrated. The remote shutoff valve  590  illustrated in  FIG.  5    may correspond to the automated remote shutoff valve  390  or  490  of  FIGS.  2 - 4   , respectively. The remote valve assembly  500  includes an inlet port  591  configured for fluid communication with an upstream fluid path, such as the length of tubing  360  or  460  of  FIGS.  3  and  4   , and an outlet port  592  configured for fluid communication with a downstream fluid path component, such as the patient delivery tubing  395 ,  495  ultimately connected to the vasculature of the patient. In some embodiments, the valve assembly  500  further includes a hemodynamic monitoring port  593  configured for fluid communication with a pressure sensor, such as the hemodynamic monitor  380 ,  480  of  FIGS.  3  and  4   , respectively. 
     The remote valve assembly  500  further includes an actuator element  510 , such as an electromechanical motor, in operative communication with the controller  900  (see  FIG.  2   ). The actuator element  510  may be configured to move the remote shutoff valve  590  between the delivery position, stop position, and hemodynamic monitoring positions described herein upon receiving a signal from the controller  900 . The controller may be programmed or configured to send the signal to the actuator element  510  in response to the air detector  200  determining the presence of at least one air bubble in the air bubble detection region  350 ,  450  (see  FIGS.  3  and  4   ). Upon receipt of the signal from the controller  900 , the actuator element  510  actuates the remote valve assembly  500  and moves the automated remote shutoff valve  590  from the delivery position to the stop position such that the inlet port  591  is isolated from the patient port  592 , such that no fluid communication possible between the input port  591  and the patient port  592 . In some embodiments, where the fluid injection protocol requires monitoring of the hemodynamic signal of the patient, the controller  900  may signal the actuator element  510  to move the automated remote shutoff valve  590  from the delivery position or the stop position to a hemodynamic monitoring position where fluid communication is provided between the hemodynamic monitoring port  593  and the patient port  592 . 
     Referring now to  FIGS.  6 - 14   , embodiments of the present disclosure may include various fluid path tubing elements configured to lengthen and increase the volume of the fluid path between the air bubble sensing region  350 ,  450  and the remote shutoff valve  390 ,  490  (see  FIGS.  2 - 4   ). The total length and/or volume of the fluid path tubing element may be determined by injection and apparatus parameters, such as flow rate, fluid viscosity, ID of tubing, and the actuation time of the remote shutoff valve  390 ,  490  as described herein. According to various embodiments, since the air bubbles are at least temporarily trapped or suspended in the fluid path tubing element upon moving the remote shutoff valve  390 ,  490  to the stop position, injection of air into the patient can be prevented. The various fluid path tubing elements may be configured to further reduce a footprint of the tubing between the air bubble sensing region  350 ,  450  and the remote shutoff valve  390 ,  490 , for example to reduce the space occupied the tubing in an injection suit, reduce packaging size, increase ease of handling, reduce disposal volume, increase ease of manufacture, etc. 
     With reference to  FIGS.  6 - 10   , an embodiment of the fluid path assembly  400  according to the present disclosure includes a fluid path tubing element  610  associated with each of the syringes  10 . For clarity, some of the components of the fluid path assembly  400  are not specifically identified in  FIG.  6   . However, the structure and function of such unidentified components are analogous to those described herein with reference to  FIG.  4   . The fluid path tubing element  610  is provided in at least a portion of the length of tubing  460  between the air detector  200  and the fluid mixing connector element  487 . While  FIG.  6    illustrates the fluid path tubing elements  610  upstream of the three-way stopcock  415 A, in other embodiments, the fluid path tubing elements  610  may be located downstream of the three-way stopcock  415 A, for example after the three-way stopcock  415 A and before fluid mixing connector element  487 . 
     With continued reference to  FIG.  6    and further reference to  FIGS.  7 - 10   , the fluid path tubing element  610  may have a co-parallel, zig-zag fluid path configuration including a tubing portion  620  having a plurality of parallel individual tubes  622 , and two end cap elements  630  configured to connect adjacent open ends of the tubing portion  620 . The tubing portion  620  and the two end cap elements  630  may be formed from a medical grade polymer, metal, or composite material, such as rigid, non-compliant material, and may be formed by a molding process, such as injection molding. A total length and volume of the individual tubes  622  and tubing elements of the end cap elements  630  of the tubing portion  620  may be greater than the volume distance that an air bubble can travel or expand in the actuation time of the remote shutoff valve  490  after an air bubble detection event. As such, between the time at which air is detected in the air bubble sensing region  450  and the time at which the remote shutoff valve  390 ,  490  reaches the stop position subsequent to actuation by the controller  900 , the air bubbles have insufficient time to travel the entire length and volume of tubing in the tubing portion  620  and are therefore isolated in the tubing portion  620  once the remote shutoff valve  490  is in the closed position. The air bubbles are thus contained within the fluid path tubing element  610 . In certain embodiments, the plurality of individual tubes  622  of the tubing portion  620  may be substantially straight and parallel to one another, whereas in other embodiments, the individual tubes  622  may be in a configuration that is not parallel but nevertheless reduces the overall footprint of the tubing portion  620  and the fluid path tubing element  610 . For example, the individual tubes  622  may be curved, spiral, circular, helical wavy, undulating, etc. In addition, although the plurality of individual tubes  622  are illustrated in a substantially co-planar orientation, in other embodiments, the plurality of individual tubes  622  may be arranged in a more 3-dimensional manner, for example as a block or other 3D arrangement of parallel tubes. 
     As described herein, the fluid injector system  1000 ,  2000  according to various embodiments of the present disclosure may take from 60 milliseconds to 90 milliseconds, for example in one embodiment approximately 80 milliseconds, to stop a high pressure (e.g. 1200 psi) injection procedure via actuation of the remote shutoff valve  390 ,  490 . Total actuation time to stop such an injection procedure may include time detecting an air bubble by the air detector  200 ; time communicating to the controller  900  that an air bubble has been detected; time for the controller  900  actuating the remote shutoff valve  390 ,  490  to the stop position; and time until the patient delivery tubing  395 ,  495  is fully isolated from the length of tubing  360 ,  460  to prevent fluid continued fluid flow from one or more of rapid flow rate, compliance release, and/or bubble expansion from continuing into the patient. At the high injection pressures typical of CV injection procedures, an air bubble may move from 2.8 mL to 3.6 mL of the volume of the fluid path over the 70 milliseconds to 100 milliseconds between detection of the air bubble and valve closing/injection halting. For example, at approximately 1200 psi, an air bubble may travel a distance corresponding to 3.2 mL over 80 milliseconds at a flow rate of 30 mL/sec in a tubing with a 0.072 inch ID. The distance equivalence of 3.2 mL volume for such an embodiment may be approximately 1200 millimeters (or approximately 4 feet) of tubing length travelled during 80 milliseconds. Thus, even with a rapid response time, an air bubble may travel or expand a significant distance after air detection and before system shutdown. 
     Based on parameters such as tubing ID, the actuation time of the remote shutoff valve  390 ,  490 , and other factors described herein, the total length of the individual tubes  622  may be selected to ensure that air bubbles have insufficient time to travel the entire length of tubing in the tubing portion  620  upon detection of the bubbles and actuation of the remote shutoff valve  390 ,  490 . In some embodiments, the total fluid path length of the individual tubes  622  may be between approximately 1000 millimeters and approximately 1400 millimeters, and in some embodiments may be approximately 1200 millimeters (or between approximately 3.5 feet and approximately 4.5 feet, and in some embodiments may be approximately 4 feet) to ensure that air bubbles detected in the air detection region  650  are not injected into the patient. 
     With continued reference to  FIGS.  6 - 10   , the end caps  630  of the fluid path tubing element  610  may include an inlet port  633  or outlet port  634  for providing fluid communication to and from the fluid path tubing element  610 . The inlet port  633  may be configured to provide fluid communication to the air bubble sensing region  450 , and the outlet port  634  may be configured to provide fluid communication to a downstream portion of the length of tubing  460 . The end caps  630  may include one or more u-turn elements  635  that connect the plurality of individual tubes  622  in series. For example, each of the u-turn elements  635  may define a 180° turn to divert fluid flow from one of the individual tubes  622  to an adjacent individual tube  622 , creating a zig-zag pathway for the fluid flow through the fluid path tubing element  610  to form a fluid path from the inlet port  633  to the outlet port  634 . Fluid may thus flow into the inlet port  633  of the fluid path tubing element  610  from the syringe  10 , through all of the plurality of individual tubes  622  in series, and out of the outlet port  634  of the fluid path tubing element  610  toward the patient. In some embodiments, the total fluid path length of the individual tubes  622  and the u-turn elements  635  may be greater than a distance that an air bubble can travel or expand during the actuation time of the at least one shutoff valve  390 ,  490 . In some embodiments, the total fluid path length of the individual tubes  622  and the u-turn elements  635  may be between approximately 1000 millimeters and approximately 1400 millimeters, and in some embodiments may be approximately 1200 millimeters (or between approximately 3.5 feet and approximately 4.5 feet, and in some embodiments may be approximately 4 feet) to ensure that air bubbles detected in the air detection region  650  are not injected into the patient. 
     Referring particularly to  FIG.  8   , the tubing portion  620  and the two end cap elements  630  may be manufactured as separate portions and then combined to form the fluid path tubing element  610 . Manufacture as individual elements may be more readily accomplished during a molding process, such as an injection molding process, as removal of the molded elements from an injection mold may be simpler than attempting to mold the entire fluid path tubing element  610  in a single piece. The two end cap elements  630  may be bonded to opposing end of the tubing portion  620 , for example by gluing, adhesion, welding, solvent welding, laser welding, and the like, such that the bonded connection may withstand the high pressures typical of angiography or other injection protocols (up to, e.g., 1200 psi). Other reinforcing features may be included to ensure non-separation of the two end cap elements  630  from the tubing portion  620 . 
     In some embodiments, the inlet port  633  of the fluid path tubing element  610  may be configured to serve as the air bubble detecting region  450 . In such embodiments, the inlet port  633  may include engagement features for directly interfacing with corresponding engagement features of the air detector  200 , thereby holding the fluid path tubing element  610  in place relative to the injector housing  12  (see  FIGS.  1 A- 2   ) and simplifying installation and setup of the fluid path assembly  400 . Further, in certain embodiments, the inlet port  633  of the fluid path tubing element  610  including the air bubble detecting region  450  may be configured for direct connection with a distal fluid path outlet of a syringe  10 . For example, the inlet port  633  may include a fluid path connector element such as connector element  305  (see  FIG.  3   ), such as described in International PCT Application No. PCT/US2021/018523, the disclosure of which is incorporated by this reference in its entirety. 
     Referring now to  FIGS.  11 - 12   , another embodiment of the fluid path tubing element  500  is illustrated. The fluid path tubing element  500  includes at least one fluid path, for example a first fluid path  510 A for a medical fluid, such as an imaging contrast media, and a second fluid path  510 B for a flushing fluid, such as saline or Ringer&#39;s lactate. The first fluid path  510 A and second fluid path  510 B may be rigidly held by one or more support cross-members  590 . The support cross-members  590  do not facilitate fluid flow, but rather may serve as a structural connection between the first fluid path  510 A and second fluid path  510 B to assist with installation and holding of the fluid path tubing element  500 . The first fluid path  510 A and second fluid path  510 B include respective fluid inlets  533 A,  533 B and respective fluid outlets  534 A,  534 B to facilitate connection to various embodiments of the fluid path assemblies  300 ,  400  described herein. According to certain embodiments, each fluid inlet  533 A,  533 B of the fluid path tubing element  500  may include an air bubble detection region  550  configured for operative communication with the at least one air detector  200  (see e.g.  FIGS.  1 A,  1 B, and  2   ). In such embodiments, the fluid inlets  533 A,  533 B may include engagement features for directly interfacing with corresponding engagement features of the at least one air detector  200 , thereby holding the fluid path tubing element  500  in place relative to the injector housing  12  (see  FIGS.  1 A,  1 B, and  2   ) and simplifying installation and setup of the fluid path assembly. The fluid outlets  534 A,  534 B may be configured for connection to the tubing downstream of the air detector  200  such that fluid injected from the syringes  10 A,  10 B enters the fluid path tubing element  500  at the fluid inlets  533 A,  533 B, flows through the fluid paths  510 A,  510 B, and exits via the fluid outlets  534 A,  534 B toward the patient. 
       FIG.  12    illustrates a cross-sectional view of fluid path  520 A, from the fluid inlet  533 A to fluid outlet  534 A. Fluid path  520 B may be identical, or may be a mirror image of fluid path  520 A. Fluid paths  520 A,  520 B may include one or more fluid path configurations for disrupting fluid flow to facilitate air bubble retention within the fluid path tubing element  500 . In some embodiments, fluid paths  520 A,  520 B may include torturous path sections  527  having a zig-zag configuration with switchback angles ranging from 160 to 180 degrees including corners for bubble isolation. In some embodiments, fluid paths  520 A,  520 B may include wider fluid path sections  525  having an increased cross-sectional area relative to preceding fluid path sections. According to certain embodiments, as fluid and air bubbles flow through the torturous path sections  527  and/or wider fluid path sections  525  of fluid paths  520 A,  520 B the air bubbles may temporarily adhere to an inner surface of the fluid path, thereby delaying their progress from the fluid inlet  533 A to the fluid outlet  534 A and providing additional time for the actuation of the remote shutoff valve  390 ,  490 . Fluid path  520 A may include a housing  594  in which the various features described herein are defined. The housing  594  may include a first side associated with a first inner surface  595  and a second side associated with a second inner surface  598  opposite the first inner surface  595 . The first side associated with the first inner surface  595  and the second side associated with the second inner surface  598  may be formed separately from one another of a medical grade plastic, for example in an injection molding process or a printing process, and bonded to one another by gluing, adhesion, welding, solvent welding, laser welding, or the like. In some embodiments, the first side associated with the first inner surface  595  and the second side associated with the second inner surface  598  may be molded identical to one another, i.e. the first side associated with the first inner surface  595  and the second side  598  may be formed from the same mold. In other embodiments, the first side associated with the first inner surface  595  and the second side associated with the second inner surface  598  may be molded as mirror images of one another. 
     With continued reference to  FIG.  12   , the torturous path sections  527  may include a plurality of baffles  528  extending from the first inner surface  595  into the fluid path  520 A and/or from the second inner surface  598  into the fluid path  520 A. The plurality of baffles  528  are configured disrupt laminar flow through the fluid path  520 A, thereby decreasing the velocity at which air bubbles can flow through the tortious path section  527  and inducing the bubbles to adhere to the inner walls of the housing  594 . In some embodiments, at least one baffle  528  extends from the first inner surface  595  of the housing  594  and at least one baffle  528  extends from the second inner surface  598  of the housing  594 . In some embodiments, the at least one baffle  528  extending from the first inner surface  595  of the housing  594  is offset in a longitudinal direction from the at least one baffle  528  extending from the second inner surface  598  of the housing  594 . In some embodiments, each of the plurality of baffles  528  extends across a longitudinal centerline CL of the housing  594 . As such, fluid is forced to flow around the plurality of baffles  528  in order to advance toward the fluid outlet  534 . In the embodiment shown in  FIG.  12   , each of the plurality of baffles  528  is generally triangular in shape, although other shapes are also considered within the scope of the present disclosure. 
     The plurality of baffles  528  may be configured to delay air bubble flow and/or trap certain air bubbles, such as small air bubbles, by adherence to corners  529  of the torturous path sections  527 . In particular, the plurality of baffles  528  may be oriented to direct air bubbles into the corners  529  defined where the plurality of baffles  528  meet with the first inner surface  595  and/or the second inner surface  598  of the housing  594 . Air bubbles of certain sizes may exhibit surface adhesion properties that cause such air bubbles to adhere to the housing  594  and/or the plurality of baffles  528  rather than be carried along the fluid path  520 A with the medical fluid. As a result, the time that an air bubble travels through the torturous path sections  527  is increased, thereby providing additional actuation time for the controller and processor to actuate the remote shutoff valve  390 ,  490  and prevent flow of the air bubble through the valve to the patient. 
     In some embodiments, the fluid path  520 A may include a widened portion  525  having an increased cross-sectional area relative to a preceding portion of the fluid path  520 A. In some embodiments, the widened portion  525  may be located immediately downstream of one of the tortious path sections  527 , which may have a diameter less than the diameter of the wide fluid channel  525 . The increased diameter of the widened portion  525  may create a fluid pressure drop within the widened portion  525  as fluid flows into the widened portion  525 . The fluid pressure drop may slow and/or stop flow of air bubbles through the widened portion  525  and promote surface adhesion of the air bubbles to an interior surface of the housing  594 . 
     Referring now to  FIGS.  13  and  14   , another embodiment of a fluid path tubing element  700  in accordance with the present disclosure is substantially similar to the fluid path tubing element  500  of  FIGS.  11 - 12   , with like reference numerals corresponding to like parts. In contrast to the fluid path tubing element  500 , the fluid inlets  533 A,  533 B and the fluid outlets  534 A,  534 B may be oriented at approximately 70° to approximately 90° relative to the longitudinal centerline CL of the housing  594 . 
     In some embodiments, the fluid path tubing element  700  may be movable, such as by an actuator in operative communication with the controller  900  (see  FIG.  2   ). During a priming operation, in which air is purged from the fluid injector system  1000 ,  2000  prior to an injection procedure, the fluid path tubing element  700  may be moved to a priming position illustrated in  FIG.  14    such that fluid flows in the direction of arrow A. In the priming position, the fluid outlets  534 A,  534 B may be oriented spatially higher than the fluid inlets  533 A,  533 B. For example, the centerline CL of the housing  594  may be oriented substantially vertical. Because air is less dense that the medical fluid, any air bubbles in the fluid paths  520 A,  520 B may float upwards and further impelled towards the fluid outlets  534 A,  534 B during the priming operation. Thus, the buoyancy of the air bubbles, at least in part, causes the air bubbles to flow away toward the fluid outlets  534 A,  534 B in the priming position. The air bubbles may then be evacuated from the fluid path tubing element  700  by actuating the plungers  13  to purge air from the system  1000 . 
     During a delivery operation, in which fluid is injected from the syringes  10  to the patient, the fluid path tubing element  700  may be moved to an injection position. In the injection position, the fluid inlets  533 A,  533 B may be oriented spatially higher than the fluid outlets  534 A,  534 B (i.e. a rotation of approximately 180° from the position shown in  FIG.  14   ) For example, the centerline CL of the housing  594  may be oriented substantially vertical, but rotated approximately 180° relative to the priming position. Because air is less dense that the medical fluid, buoyancy directs any air bubbles in the fluid paths  520 A,  520 B upward away from the fluid outlets  534 A,  534 B. As such, the buoyancy of the air bubbles must be overcome by the force of the fluid flow in order for the air bubbles to reach the fluid outlets  534 A,  534 B. The buoyancy of the air bubbles therefore provides additional influence, in combination with volume effects and surface adhesion effects, for preventing the air bubbles from flowing out of the fluid outlets  534 A,  534 B toward the patient. Thus, the buoyancy of the air bubbles, at least in part, causes the air bubbles to flow away from the fluid outlets  534 A,  534 B in the injection position. The result may be an increase delay time of the one or more air bubble within the fluid path tubing element  700  therefore allowing additional time to actuate the remote shutoff valve  390 ,  490  by the controller. 
     Referring now to  FIG.  15   , another embodiment of the fluid path tubing set  700  is illustrated. In this embodiment, each of the plurality of baffles  528  has a directionality designed to enhance the ability of the fluid path tubing set  700  to trap air bubbles and increase adherence of the air bubble to an inner surface of the fluid path element  700 . In particular, each of the baffles  528  extends from the first side  595  or the second side  598  of the housing  594  in a direction at least partially towards the fluid outlet  534 A. When the fluid path tubing set  700  is moved to the priming position as shown in  FIG.  15   , any air bubbles present in the tortious path section  527  float upward toward the fluid outlet  534 A. The baffles  528  may be angled such that air bubbles slide along the surfaces of the baffles  528  facing the fluid inlet  533 A, progressively moving toward the fluid outlet  534 A. The air bubbles may then be purged from the fluid outlet  534 A as described herein. 
     Conversely, in the injection position of the fluid path tubing element  700 , the angle of the baffles  528  directs air bubbles into corners  529  such that the air bubbles do not flow out of the housing  594 . In the injection position of the fluid path tubing element  700  (i.e. approximately a 180° rotation from the priming position shown in  FIG.  15   ), the buoyancy of air bubbles causes the air bubble to float upwards and become trapped in the acute corners  529 , preventing the air bubbles from exiting the fluid path tubing set  700  via the fluid outlet  534 A. Further, the air bubbles are held in corners  529  outside the force of the fluid flow such that the force of fluid flow does not dislodge the air bubbles by destroying the adhering force of the surface tension of the air bubble and the inner surface of the wall. 
     Based on parameters such as tubing ID, the actuation time of the remote shutoff valve  390 ,  490 , and other factors described herein, the total length and/or volume of the fluid path tubing elements  500  and  700  of  FIGS.  11 - 15    may be selected to ensure that air bubbles have insufficient time to travel the entire length and volume of the fluid path tubing elements  500  and  700  between detection of the bubbles and complete actuation of the remote shutoff valve  390 ,  490 . In some embodiments, the total length of the fluid path tubing elements  500  and  700  may be between approximately 1000 millimeters and approximately 1400 millimeters, and in some embodiments may be approximately 1200 millimeters (or between approximately 3.5 feet and approximately 4.5 feet, and in some embodiments may be approximately 4 feet) to ensure that air bubbles detected in the air detection regions  550  are not injected into the patient. In another embodiment, the total volume of the fluid path tubing elements  500  and  700  may be greater than 2.8 mL, for example between approximately 2.8 mL to 3.6 mL of the volume and in some embodiments may be approximately 3.2 mL to ensure that air bubbles detected in the air detection regions  550  are not injected into the patient. 
     While various examples of the present disclosure were provided in the foregoing description, those skilled in the art may make modifications and alterations to these examples without departing from the scope and spirit of the disclosure. For example, it is to be understood that features of various embodiments described herein may be adapted to other embodiments described herein. Accordingly, the foregoing description is intended to be illustrative rather than restrictive. The disclosure described hereinabove is defined by the appended claims, and all changes to the disclosure that fall within the meaning and the range of equivalency of the claims are to be embraced within their scope.