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WO2023012665A1 - Commutateur d'écoulement passif pour aspiration médicale - Google Patents

Commutateur d'écoulement passif pour aspiration médicale Download PDF

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Publication number
WO2023012665A1
WO2023012665A1 PCT/IB2022/057167 IB2022057167W WO2023012665A1 WO 2023012665 A1 WO2023012665 A1 WO 2023012665A1 IB 2022057167 W IB2022057167 W IB 2022057167W WO 2023012665 A1 WO2023012665 A1 WO 2023012665A1
Authority
WO
WIPO (PCT)
Prior art keywords
proximal
plug
distal
flow switch
internal cavity
Prior art date
Application number
PCT/IB2022/057167
Other languages
English (en)
Inventor
Rónán WOOD
Original Assignee
Covidien Lp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US17/809,118 external-priority patent/US20230031759A1/en
Application filed by Covidien Lp filed Critical Covidien Lp
Priority to EP22757363.1A priority Critical patent/EP4380474A1/fr
Priority to CN202280050208.7A priority patent/CN117677351A/zh
Publication of WO2023012665A1 publication Critical patent/WO2023012665A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/22—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/90—Negative pressure wound therapy devices, i.e. devices for applying suction to a wound to promote healing, e.g. including a vacuum dressing
    • A61M1/96—Suction control thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M39/00—Tubes, tube connectors, tube couplings, valves, access sites or the like, specially adapted for medical use
    • A61M39/22—Valves or arrangement of valves
    • A61M39/24—Check- or non-return valves
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/22—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for
    • A61B2017/22079—Implements for squeezing-off ulcers or the like on inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; for invasive removal or destruction of calculus using mechanical vibrations; for removing obstructions in blood vessels, not otherwise provided for with suction of debris
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2217/00—General characteristics of surgical instruments
    • A61B2217/002—Auxiliary appliance
    • A61B2217/005—Auxiliary appliance with suction drainage system
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M39/00—Tubes, tube connectors, tube couplings, valves, access sites or the like, specially adapted for medical use
    • A61M39/22—Valves or arrangement of valves
    • A61M39/24—Check- or non-return valves
    • A61M2039/2473—Valve comprising a non-deformable, movable element, e.g. ball-valve, valve with movable stopper or reciprocating element
    • A61M2039/248—Ball-valve

Definitions

  • medical aspiration can be used to remove material from a patient.
  • medical aspiration can be used to remove a thrombus, such as a clot or other occlusion, from a blood vessel of a patient.
  • An aspiration catheter can be used to remove a thrombus from a hollow anatomical structure (e.g., a blood vessel) of a patient.
  • a distal opening of the catheter may be positioned in the hollow anatomical structure near a thrombus and an aspiration force can be applied to a lumen of the aspiration catheter in order to draw the thrombus through the catheter lumen and out of the hollow anatomical structure.
  • an aspiration system includes an aspiration catheter fluidically coupled to a flow switch (also referred to herein as a valve) configured to passively (e.g., without human intervention) close in response a presence of an aspirated fluid flow through the valve, in order to reduce or prevent further fluid flow through the aspiration catheter from the hollow anatomical structure.
  • a flow switch also referred to herein as a valve
  • the valve includes a spring-suspended plug configured to close the valve in response to an abovethreshold drag force applied by the fluid flow onto the plug.
  • the valve Upon the sufficient reduction or total absence of the fluid flow (e.g., when an opening of the catheter engages a more- solid material, such as a thrombus), the valve is configured to automatically return to an “open” position, enabling aspiration of the more-solid material through the catheter.
  • the devices, systems, and techniques of this disclosure may provide one or more advantages and benefits. For instance, by passively closing the switch in the presence of a fluid flow, the systems and techniques described herein can help reduce the undesired and/or unnecessary withdrawal of a body fluid, such as blood, from a body of a patient during an aspiration procedure, while still allowing for effective removal of targeted material. This more-precise targeted aspiration may help improve patient outcomes. Additionally, the passive nature of the flow switch enables the switch to rapidly close with no required human intervention, enabling the clinician to focus on other aspects of the aspiration procedure. Additionally, the passive flow switches described herein do not require any power source or electronic control, enabling the flow switches to operate without external electrical connections, thereby preserving the sterile field during the medical procedure.
  • a flow switch includes a housing defining an internal cavity and proximal and distal openings to the internal cavity, wherein the internal cavity is configured to receive an aspirated fluid flow from a catheter; and a plug disposed within the internal cavity and configured to: move proximally, in response to an above-threshold drag force from the fluid flow applied to a distal-facing surface of the plug, to close the proximal opening; and move distally to open the proximal opening in response to an absence of the fluid flow within the internal cavity.
  • a medical aspiration system includes a suction source; aspiration tubing fluidically coupled to the suction source, wherein the aspiration tubing defines an inner lumen; and a flow switch fluidically coupled to the aspiration tubing, the flow switch comprising: a housing defining an internal cavity configured to receive an aspirated fluid flow from a catheter; and a proximal opening to the internal cavity, the proximal opening configured to fluidically connect to a distal end of the aspiration tubing; and a distal opening to the internal cavity, the distal opening configured to fluidically connect to the catheter; and a plug disposed within the internal cavity and configured to: move proximally, in response to an above-threshold drag force from the fluid flow applied to a distal-facing surface of the plug, to close the proximal opening; and move distally to open the proximal opening in response to an absence of the fluid flow within the internal cavity.
  • a method includes fluidically coupling a proximal opening to an internal cavity of a flow switch to a distal end of aspiration tubing coupled to a suction source; fluidically coupling a distal opening to the internal cavity of the flow switch to a proximal end of an aspiration catheter, wherein the flow switch further comprises a plug disposed within the internal cavity and configured to: move proximally, in response to an above-threshold drag force from the fluid flow applied to a distal-facing surface of the plug, to close the proximal opening; and move distally to open the proximal opening in response to an absence of the fluid flow within the internal cavity; introducing a distal portion of the catheter into vasculature of a patient; aspirating a thrombus from the vasculature of the patient via the catheter; and withdrawing the catheter from the vasculature of the patient.
  • FIG. 1 is a schematic diagram illustrating an example aspiration system including a passive flow switch.
  • FIG. 2A is a cross-sectional view of an example of the flow switch of FIG. 1 in an “open” configuration.
  • FIG. 2B is a cross-sectional view of the flow switch of FIG. 2A in a “closed” configuration.
  • FIG. 3 is a cross-sectional view of the flow switch of FIGS. 2A and 2B.
  • FIG. 4A is a cross-sectional view of another example of the flow switch of
  • FIG. 4B is another cross-sectional view of the flow switch of FIG. 4A.
  • FIG. 5 is a perspective view of an example proximal housing portion of the flow switch of FIGS. 4A and 4B.
  • FIG. 6A is a side view of an example plug of the flow switch of FIGS. 4A and 4B.
  • FIG. 6B is an end view of the example plug of FIG. 6A.
  • FIG. 7 is a flow diagram of an example method of using an aspiration system. DETAILED DESCRIPTION
  • an aspiration system includes a flow switch (also referred to herein as a “valve”) configured to passively (e.g., without further human intervention) close a fluid pathway from a body of a patient to outside the patient (e.g., a discharge reservoir configured to collect aspirated material) in response to the presence of an above-threshold fluid flow aspirated into a catheter and through the valve.
  • a flow switch also referred to herein as a “valve”
  • a fluid pathway from a body of a patient to outside the patient e.g., a discharge reservoir configured to collect aspirated material
  • the valve When the fluid flow is sufficiently reduced or is no longer present, such as when a distal opening of the catheter is in contact with a more-solid thrombus material, the valve is configured to passively reopen the fluid pathway such that the thrombus material may be removed from the patient through the catheter lumen.
  • the passive flow switch includes a plug suspended between opposing proximal and distal springs. While a body fluid is aspirated proximally through the catheter, an above-threshold drag force imparted (e.g., from the above-threshold fluid flow) onto the plug causes the plug to move proximally and seal a proximal opening of the switch, thereby modifying (e.g., restricting or preventing) the flow of fluid through the switch. In this way, the flow switch helps reduce an undesired and unnecessary aspiration removal of fluid, thereby improving medical aspiration procedures.
  • an above-threshold drag force imparted e.g., from the above-threshold fluid flow
  • the passive nature of the flow switch enables the switch to rapidly close with no required human intervention, enabling the clinician to focus on other aspects of the aspiration procedure. Additionally, the passive flow switches described herein do not require any power source or electronic control circuitry, enabling the flow switches to operate without external electrical connections, thereby preserving the sterile field during the medical procedure.
  • FIG. 1 is a schematic diagram illustrating an example medical aspiration system 100 including a suction source 102, a discharge reservoir 104, an aspiration catheter 108, and a flow switch 110.
  • Aspiration system 100 may be used to treat a variety of conditions, including thrombosis. Thrombosis occurs when a thrombus (e.g., a blood clot or other material such as plaques or foreign bodies) forms and obstructs vasculature of a patient.
  • a thrombus e.g., a blood clot or other material such as plaques or foreign bodies
  • medical aspiration system 100 may be used to treat a pulmonary embolism or deep vein thrombosis, which may occur when a thrombus forms in a deep vein of a patient, such as in a leg of the patient.
  • Aspiration system 100 is configured to remove fluid via catheter 108, e.g., draw fluid from catheter 108 into discharge reservoir 104, via a suction force applied by suction source 102 to catheter 108 (e.g., to an inner lumen of catheter 108).
  • Catheter 108 includes an elongated body 112 defining a catheter lumen (not shown in FIG. 1) and terminating in a distal opening 114.
  • a clinician may position distal opening 114 of catheter 108 in a blood vessel of the patient near the thrombus or other occlusion, and apply a suction force (also referred to herein as suction, vacuum force, negative pressure, or aspiration force) to the catheter 108 (e.g., to one or more lumens of the catheter) to engage the thrombus with suction force at distal opening 114 of catheter 108.
  • suction source 102 can be configured to create a negative pressure within the inner lumen of catheter 108 to draw a material from the inside the blood vessel into the catheter lumen via distal opening 114 of catheter 108.
  • the negative pressure within the inner lumen can create a pressure differential between the inner lumen and the environment external to at least a distal portion of catheter 108 that causes the material, e.g., a thrombus, fluid (e.g., blood, saline introduced into the patient as part of the aspiration procedure, or the like), and/or other material, to be introduced from the blood vessel into the catheter lumen via catheter opening 114.
  • the fluid may flow from patient vasculature, into the catheter lumen via distal opening 114, and subsequently through aspiration tubing 116 (also referred to herein as “vacuum tube 116”) into discharge reservoir 104.
  • the clinician may remove aspiration catheter 108 with the thrombus held within opening 114 or attached to the distal tip of elongated body 112, or suction off pieces of the thrombus (or the thrombus as a whole) until the thrombus is removed from the blood vessel of the patient through a lumen of aspiration catheter 108 itself and/or through the lumen of an outer catheter in which aspiration catheter 108 is at least partially positioned.
  • the outer catheter can be, for example, a guide catheter configured to provide additional structural support to the aspiration catheter.
  • aspiration of thrombus can be performed concurrently with use of a thrombectomy device, such as a thrombus removal basket, to facilitate removal of thrombus via mechanical thrombectomy as well as via aspiration.
  • suction force is intended to include, within its scope, related concepts such as suction pressure, vacuum force, vacuum pressure, negative pressure, fluid flow rate, and the like.
  • a suction force can be generated by a vacuum, e.g., by creating a partial vacuum within a sealed volume fluidically connected to catheter 108, or by direct displacement of liquid in catheter 108 and/or tubing 116 via (e.g.) a peristaltic pump, or otherwise. Accordingly, suction forces or suction as specified herein can be measured, estimated, computed, etc. without need for direct sensing or measurement of force.
  • suction source 102 can comprise a pump (also referred to herein as “pump 102” or “vacuum source 102”).
  • the suction source 102 can include one or more of a positive displacement pump (e.g., a peristaltic pump, a rotary pump, a reciprocating pump, or a linear pump), a direct-displacement pump (e.g., a peristaltic pump, or a lobe, vane, gear, or piston pump, or other suitable pumps of this type), a direct- acting pump (which acts directly on a liquid to be displaced or a tube containing the liquid), an indirect-acting pump (which acts indirectly on the liquid to be displaced), a centrifugal pump, and the like.
  • a positive displacement pump e.g., a peristaltic pump, a rotary pump, a reciprocating pump, or a linear pump
  • a direct-displacement pump e.g., a peristaltic pump, or a lobe, vane, gear, or piston pump, or other suitable pumps of this type
  • a direct- acting pump which acts directly on a liquid to be
  • An indirect-acting pump can comprise a vacuum pump, which displaces a compressible fluid (e.g., a gas such as air) from the evacuation volume (e.g., discharge reservoir 104, which can comprise a canister), generating suction force on the liquid.
  • a compressible fluid e.g., a gas such as air
  • the evacuation volume can be considered part of the suction source.
  • suction source 102 includes a motor-driven pump, while in other examples, suction source 102 can include a syringe, and mechanical elements such as linear actuators, stepper motors, etc.
  • the suction source 102 could comprise a water aspiration venturi or ejector jet.
  • Aspiration system 100 includes control circuitry 120 configured to control a suction force applied by suction source 102 to catheter 108.
  • control circuitry 120 can be configured to directly control an operation of suction source 102 to vary the suction force applied by suction source 102 to the inner lumen of catheter 108, e.g. by controlling the motor speed, or stroke length, volume or frequency, or other operating parameters, of suction source 102.
  • control circuitry 120 can be configured to control one or more functions of flow switch 110. Other techniques for modifying a suction force applied by suction source 102 to the inner lumen of catheter 108 can be used in other examples.
  • Control circuitry 120 may include any combination of integrated circuitry, discrete logic circuity, analog circuitry, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), or field-programmable gate arrays (FPGAs).
  • control circuitry 120 may include multiple components, such as any combination of one or more microprocessors, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry, and/or analog circuitry.
  • control circuitry 120 may further include, additionally or alternatively to electric-based processors, one or more controls that operate using fluid motion power (e.g., hydraulic power) in combination with or in addition to electricity.
  • control circuitry 120 can include a fluid circuit comprising a fluid circuit comprising a plurality of fluid passages and switches arranged and configured such that, when a fluid (e.g., liquid or gas) flows through the passages and interacts with the switches, the fluid circuit performs the functionality of control circuitry 120 described herein.
  • Memory 122 may store program instructions, such as software, which may include one or more program modules, which are executable by control circuitry 120. When executed by control circuitry 120, such program instructions may cause control circuitry 120 to provide the functionality ascribed to control circuitry 120 herein.
  • the program instructions may be embodied in software and/or firmware.
  • Memory 122, as well as other memories described herein, may include any volatile, non-volatile, magnetic, optical, or electrical media, such as a random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, or any other digital media.
  • RAM random access memory
  • ROM read-only memory
  • NVRAM non-volatile RAM
  • EEPROM electrically-erasable programmable ROM
  • flash memory or any other digital media.
  • control circuitry 120 and/or memory 122 can be physically separate from each other.
  • some amount of a body fluid may be incidentally withdrawn during the aspiration procedure. For instance, while approaching and aspirating a thrombus with a distal opening of the catheter, the clinician may incidentally aspirate and remove a volume of the patient’s blood, e.g., that is not inherently necessary to withdraw as part of the procedure.
  • aspiration system 100 includes flow switch 110 (also referred to herein as “valve 110”), configured to mitigate or prevent the incidental withdrawal of the patient’s blood during aspiration.
  • flow switch 110 is configured to passively close to restrict aspiration of a body fluid from a body of a patient.
  • Flow switch 110 is configured to be fluidically coupled to aspiration catheter 108 at a distal portion of flow switch 110, and fluidically coupled to vacuum tubing 116 at a proximal portion of flow switch 110, thereby defining a continuous fluid flow pathway (e.g., a continuous lumen) through aspiration system 100.
  • flow switch 110 is configured to passively close the continuous pathway to inhibit or disrupt a proximal flow of a body fluid, such as blood.
  • flow switch 110 is configured to passively re-open the continuous pathway, thereby enabling effective aspiration of thrombus material into distal catheter opening 114 and proximally through a catheter lumen defined by elongated body 112 of catheter 108.
  • flow switch 110 includes a housing defining an internal cavity and a plug disposed within the internal cavity.
  • the plug is positioned between opposing proximal and distal springs (not shown in FIG. 1).
  • each spring is operatively coupled to an opposing side of the plug.
  • the plug is operatively coupled to only one of the springs, but configured to contact the other spring in certain configurations.
  • flow switch 110 includes either a proximal spring or a distal spring, but not both.
  • FIGS. 2A and 2B depict cross- sectional side views of an example flow switch 210, which is an example of flow switch configuration, in which an aspirated substance is freely able to flow proximally (e.g., right-to-left, from the perspective of FIG.
  • switch 210 through switch 210 along a continuous pathway generally indicated by central axis 220.
  • flow switch 210 is depicted in a “closed” configuration, in which the continuous pathway is obstructed to block fluid flow through flow switch 210.
  • flow switch 210 includes a housing 212 that defines an internal cavity 214.
  • housing 212 includes both a proximal housing portion 212A and a distal housing portion 212B.
  • Proximal and distal housing portions 212A, 212B may be shaped and sized so as to be mutually interlocking or otherwise mechanically connected, and fluidically sealed by an O-ring 216 so as to define the internal cavity 214.
  • housing 212 As defined by housing 212, internal cavity 214 extends distally (e.g., left-to- right, from the perspective of FIG. 2A) from a proximal housing opening 218A to a distal housing opening 218B along a longitudinal axis 220. Housing 212 is configured to removably interconnect with vacuum tubing 116 at proximal housing opening 218A, and to removably interconnect with elongated body 112 of catheter 108 (FIG. 1) at distal housing opening 218B.
  • internal cavity 214 fluidically connects vacuum tubing 116 and elongated body 112 of catheter 108. That is, a fluid pathway is defined by vacuum tubing 116, elongated body 112, and flow switch.
  • Housing 212 of flow switch 210 defines a proximal valve opening 220A and a distal valve opening 220B, the openings 220A, 220B defining openings into cavity 214.
  • flow switch 210 further includes a plug 222 positioned within internal cavity 214.
  • plug 222 includes a substantially spherical object, however, as detailed further below with respect to FIGS. 4, 6A, and 6B, plug 222 can have other suitable configurations, such as a hemispherical or conical shape.
  • Plug 222 is movably positioned or suspended within internal cavity 214 by a biasing mechanism.
  • a “biasing mechanism” includes any suitable device configured to retain plug 222 in an equilibrium position in the absence of outside forces acting upon the plug, or equivalently, to passively (e.g., without human intervention) restore plug 222 toward the equilibrium position when outside forces acting upon plug 222 are removed.
  • the biasing mechanism includes a proximal spring 224A and a distal spring 224B (collectively, “springs 224”) operatively coupled (e.g., configured to apply a biasing force) to an opposing side of plug 222 from proximal spring 224A.
  • the biasing mechanism may include, as non-limiting examples, one or more elastic bands operatively coupled to plug 222, one or more magnetic objects configured to attract or repel plug 222 toward the equilibrium position, or the like.
  • the biasing mechanism may include both a proximal spring 224A and a distal spring 224B, but plug 222 may be operatively coupled to only the proximal spring 224A or the distal spring 224B, but not both.
  • plug 222 may be operatively coupled to distal spring 224B but not to proximal spring 224A.
  • plug 222 may be configured to contact proximal spring 224A in certain configurations of flow switch 210, such as when flow switch 210 is in the “closed” configuration and plug 222 is biased proximally within internal cavity 214.
  • plug 222 may be operatively coupled to proximal spring 224A but not to distal spring 224B, wherein plug 222 is configured to contact distal spring 224B while flow switch 210 is in the “open” configuration and plug 222 is biased distally.
  • the biasing mechanism of flow switch 210 may include either a proximal spring 224A or a distal spring 224B, but not both.
  • flow switch 210 may include only proximal spring 224A and not distal spring 224B, wherein a proximal fluid flow through internal cavity 214 applies a drag force onto plug 222 to compress proximal spring 224A and bias plug 222 proximally.
  • flow switch 210 may include only distal spring 224B and not proximal spring 224A, wherein a proximally oriented fluid flow through internal cavity 214 applies a drag force onto plug 222 to expand distal spring 224B and bias plug 222 proximally.
  • springs 224 can include any suitable type of spring, such as, but not limited to, a coil spring, a wave spring, a leaf spring, or the like. Further, as discussed in further detail below, springs 224 can be tension springs or compression springs.
  • the biasing mechanism includes both proximal spring 224A and distal spring 224B, and in which both springs 224 are operatively coupled to a respective opposing side of plug 222, the proximal and distal springs 224A, 224B may both include or be “tension” springs.
  • both of the springs 224 may be in a respective at-least-partially expanded configuration, thereby applying a respective tension force onto either side of plug 222.
  • proximal fluid flow through internal cavity 214 applies an above-threshold drag force onto plug 222
  • the resulting proximal motion of plug 222 will further expand distal spring 224B and will enable proximal spring 224Ato compress toward its spring-equilibrium position.
  • the proximal and distal springs 224 may both include or be “compression” springs.
  • both of the springs 224 may be in a respective at-least-partially compressed configuration, thereby applying a respective compression force on either side of plug 222. That is, when a proximal fluid flow through internal cavity 214 applies an above-threshold drag force onto plug 222, the resulting proximal motion of plug 222 will further compress proximal spring 224A and will enable distal spring 224B to expand toward its spring-equilibrium position.
  • one of tension or compressive springs may be referred to in the description herein, but in other examples, springs 224 can be configured to apply the other of compressive or tension forces to plug 222.
  • springs 224 each impart a respective compression force (or alternatively, a respective tension force, as described above) onto plug 222 that, in the absence of additional external forces, bias plug 222 distally toward distal valve opening 220B.
  • Springs 224 can directly (e.g., direct physical contact) or indirectly contact plug 222 (e.g., via an intermediary structure that transmits the force from the respective spring 224 to plug 222).
  • proximal valve opening 220A which defines a generally circular opening that substantially conforms to a cross-sectional profile of plug 222, as depicted in the cross- sectional transverse view of FIG.
  • distal valve opening 220B defines a substantially irregular cross-sectional shape that does not substantially conform to a cross-sectional profile of plug 222.
  • flow switch 210 includes one or more gaps 314 (FIG. 3) enabling a fluid or other material to flow proximally around plug 222 and through internal cavity 214.
  • a clinician may position distal opening 114 of catheter 108 within vasculature or another hollow anatomical structure of a patient, near a target treatment site (e.g., a part of a blood vessel including a thrombus).
  • the clinician may activate suction source 102 to aspirate occlusive material into distal opening 114 of catheter 108.
  • distal opening 114 may be only partially occluded via contact with thrombus material, or in other instances, may not be occluded by thrombus material at all, such as when distal opening 114 is not yet positioned into engagement with the thrombus within the patient.
  • suction source 102 may begin to aspirate an amount of a body fluid, such as blood, into distal opening 114, through elongated body 112 and aspiration tubing 116, and into discharge reservoir 104 to be subsequently discarded. It may be undesirable to remove relatively large volumes of body fluid from the patient during the aspiration procedure.
  • Flow switch 110 is configured to passively transition from the “open” configuration depicted in FIG. 2A to the “closed” configuration depicted in FIG. 2B to restrict or prevent further aspiration of the body fluid from the body of the patient.
  • proximal drag force is sufficient to overcome the threshold compression forces imparted by proximal and distal springs 224A, 224B
  • plug 222 will translate proximally toward proximal valve opening 220A.
  • proximal spring 224A will compress from a less-compressed configuration to a more-compressed configuration, thereby imparting a greater distal compression force onto a proximal side 222A of plug 222.
  • distal spring 224B will expand from a more-compressed configuration toward a less-compressed configuration, thereby imparting a lesser proximal compression force onto distal side 222B of plug 222.
  • distal spring 224B may continue to expand past its own springequilibrium position into an expanded configuration, thereby imparting a distal tension force onto distal side 222B of plug 222.
  • proximal valve opening 220A is shaped so as to substantially conform (e.g., conform or nearly conform to the extent permitted by manufacturing tolerances) to a cross-sectional profile of plug 222 such that, when plug 222 is biased proximally against proximal valve opening 220A, proximal valve opening 220A is substantially occluded by plug 222 (e.g., fully occluded or nearly fully occlude) and, by extension, the continuous pathway or lumen through internal cavity 214 is likewise occluded, preventing further fluid flow through flow switch 210. This may help reduce or even stop the further removal of the body fluid from the body of the patient.
  • a pressure seal or vacuum seal may form to retain plug 222 in place in the proximal “closed” position.
  • the aspiration force from suction source 102 can provide a relatively low-pressure region on the proximal side of plug 222, and the venous blood pressure of the patient can provide a relatively high-pressure region on the distal side of plug 222, thereby proximally biasing plug 222 and retaining flow switch 210 in the “closed” configuration shown in FIG. 2B.
  • housing 212 defines a plurality of leak channels 226, distributed circumferentially around proximal valve opening 220A, and extending between a relatively central region of internal cavity 214 and a more-proximal region of internal cavity 214.
  • Leak channels 226 enable a relatively small amount of fluid to bypass or circumvent proximal valve opening 220A, even when proximal valve opening 220A is occluded by plug 222 (e.g., when flow switch 210 is in a closed configuration).
  • leak channels 226 Although the amount of fluid aspirated through leak channels 226 may be relatively negligible, the associated transmission of fluid pressure through leak channels 226 enables flow switch 210 to revert back to the open configuration depicted in FIG. 2A once the fluid flow through the channels 226 is removed.
  • the fluid flow into elongated body 112 may be disrupted or entirely prevented (e.g., when distal catheter opening 114 is pressure-sealed against the occlusive material by suction source 102).
  • the fluid pressure on the distal side of plug 222 may begin to drop, and eventually equalize with the fluid pressure on the proximal side of plug 222 via leak channels 226.
  • the devices, systems, and techniques of this disclosure enable a clinician to use aspiration catheter 108 to “search” or “probe” for occlusive material within the vasculature of a patient (e.g., with the assistance of visual fluoroscopy) without withdrawing an excessive amount of the patient’s blood or other body fluid in the process.
  • flow switch 210 (and the other example flow switches described herein) enables a clinician to primarily aspirate more -solid or more -viscous thrombus material, and not more-liquid or less-viscous patient material, even absent a precise alignment and occlusion of distal catheter opening 114 with the thrombus.
  • FIG. 3 is a cross-sectional view of the example flow switch of FIGS. 2A and 2B, wherein the cross-section is taken orthogonal to longitudinal axis 220.
  • distal valve opening 220B (indicated by the thick black line in FIG. 3) is a geometrically irregular shape that does not conform to a cross-sectional profde of plug 222 when plug 222 is biased distally against distal valve opening 220B.
  • distal housing portion 212B defines a plurality of plug supports 316 extending radially inward into internal cavity 214 (FIGS. 2A and 2B).
  • Plug supports 316 are configured to position plug 222 approximately radially centered within internal cavity 214, while enabling plug 222 to move axially (e.g., proximally and distally along longitudinal axis 220) in response to the presence or absence of a fluid flow. As shown in FIG. 3, each circumferentially adjacent pair of plug supports 316 defines a respective gap 314 therebetween. In some examples, but not all examples, supports 316 may be sized and shaped such that each gap 314 has a cross-sectional area that is larger than a cross- sectional area of the inner lumen of the elongated body 112 of catheter 108. In such configurations, any thrombus material aspirated into internal cavity 214 (e.g., through gaps 314) may be substantially unlikely to occlude or jam internal cavity 214.
  • flow switch 210 can include any suitable number of plug supports, such as two, three, or more than four, or one having a shape that is configured to simultaneously engage plug 222 and define gaps 314.
  • the plug supports can be evenly distributed or unevenly distributed about a common axis (e.g., longitudinal axis 220).
  • FIGS. 4A and 4B are cross-sectional side views of another flow switch 410, which is another example of flow switch 110 of FIG. 1.
  • Flow switch 410 may also be an example of flow switch 210 of FIGS. 2A-3, except for the differences noted herein.
  • flow switch 410 includes a housing 412 having proximal and distal housing portions 412A, 412B, respectively, a plug 422 suspended between proximal and/or distal springs 424A, 424B (or other suitable biasing mechanism), and leak channels 426.
  • FIG. 4A depicts flow switch 410 in an “open” configuration
  • FIG. 4B depicts flow switch 410 in a “closed” configuration.
  • FIG. 4A depicts a configuration of flow switch 410 with fully “open” leak channels 426
  • FIG. 4B depicts a configuration of flow switch 410 with fully “closed” leak channels 426.
  • proximal and distal housing portions 412A, 412B are radially nested (e.g., include portions that overlap along an axial direction) and threadably coupled via first threading 430 (or “threading 430”). Threading 430 enables a user (e.g., the clinician) to axially translate proximal and distal housing portions 412A, 412B relative to one another, thereby axially collapsing or expanding, respectively, the internal cavity 414 therebetween, and by extension, axially compressing or expanding the springs 424A, 424B extending between proximal-facing and distal-facing surfaces of internal cavity 414.
  • first threading 430 or “threading 430”. Threading 430 enables a user (e.g., the clinician) to axially translate proximal and distal housing portions 412A, 412B relative to one another, thereby axially collapsing or expanding, respectively, the internal cavity 414 therebetween, and by extension, axially
  • threading 430 enables the user to control a “closing sensitivity” of flow switch 410.
  • the user can manipulate the base or default tension force or compression force applied to plug 422 by springs 424A, 424B.
  • flow switch 410 requires an increased threshold minimum drag force (e.g., an increased threshold flow rate) from a fluid flow through internal cavity 414 in order to overcome the tension force or compression force and move plug 422 proximally to close switch 410 (i.e., fully or partially block fluid flow through switch 410).
  • flow switch 410 requires a decreased minimum threshold drag force (e.g., a decreased threshold flow rate) from a fluid flow through internal cavity 414 to overcome the tension force or compression force and move plug 422 proximally to close the switch.
  • a decreased minimum threshold drag force e.g., a decreased threshold flow rate
  • flow switch 410 includes a mechanism that enables a user to adjust or modify fluid flow through leak channels 426 in order to control a “responsiveness” of flow switch 410, or in other words, a duration or delay between the time at which a fluid flow is either introduced or removed from internal cavity 414, and the time at which the switch 410 re-opens in response to the absence of the fluid flow.
  • flow switch 410 may include a selector switch (e.g., a rotatable switch) that closes or opens different leak channels 426.
  • the selector switch may increase the responsiveness of flow switch 410 by opening additional leak channels 426, or may decrease the responsiveness of flow switch 410 by closing leak channels 426.
  • the selector switch may increase the responsiveness of flow switch 410 by opening larger leak channels and closing smaller channels, or may decrease the responsiveness of flow switch 410 by closing larger leak channels and opening smaller leak channels.
  • the selector switch includes an adjustable needle valve 432 with an external adjustment screw 434.
  • Needle valve 432 is configured to enable the user to control the responsiveness of flow switch 410 by fluidically coupling (or “opening”) leak channels 426 to proximal lumen 416A (as shown in FIG. 4A) or by fluidically occluding (or “closing”) leak channels 426 from proximal lumen 416B (as shown in FIG. 4B).
  • needle valve 432 is threadably coupled to proximal housing portion 412A via second threading 436.
  • the distal -most end 438 of needle valve 432 is located proximally from the proximal valve opening 420A, such that leak channels 426 are fluidically coupled to proximal lumen 416A.
  • flow switch 410 were in a closed configuration in which plug 422 were proximally sealed against proximal valve opening 420A (indicated by the thick black dashed line in FIG. 4A), a small amount of fluid flow could bypass plug 422 through leak channels 426.
  • the distal -most end 438 of needle valve 432 is either axially aligned with proximal valve opening 420A, or in some examples, positioned distally to the proximal valve opening 420 A, such that plug 422 directly contacts and seals the distal -most end 438 of needle valve 432, thereby fluidically occluding leak channels 426 and proximal lumen 416A.
  • adjustment screw 434 the user can select the responsiveness of the leak channels 426 from anywhere between the open configuration (FIG. 4A) and the closed configuration (FIG. 4B).
  • flow switch 410 may additionally or alternatively include a complete bypass mechanism that enables the user to hold flow switch 410 in the open configuration (FIG. 4A) regardless of the presence of a fluid flow through internal cavity 414.
  • each of proximal and distal springs 424A, 424B may include a nested pair of springs.
  • each of proximal and distal springs 424A, 424B may include more than two springs helically nested together.
  • FIG. 5 is a perspective view of the proximal housing portion 412A of the passive flow switch 410 of FIGS. 4A and 4B.
  • proximal housing portion 412 defines a protrusion 440 that in turn defines proximal valve opening 420Ato proximal lumen 416A.
  • Protrusion 440 is approximately radially centered within internal cavity 414, thereby defining an annular portion 442 of cavity 414, located circumferentially around protrusion 440.
  • the annular portion 442 of cavity 414 is configured to receive a proximal portion of proximal spring 424A that contacts proximal cavity wall 444. In such configurations, proximal spring 424A is not located within the primary fluid pathway into proximal valve opening 420Ato proximal lumen 416A, providing for improved aspiration thrombus material and reduced probability for blockage of the pathway.
  • FIGS. 6A and 6B are side and end views, respectively, of an example of plug 422 of flow switch 410 of FIGS. 4 A and 4B.
  • plug 422 of FIGS. 2A-3 which includes a substantially spherical shape configured to both fluidically seal proximal valve opening 220A as well as couple to proximal and distal springs 224A, 424B, as shown in FIGS. 6A and 6B, plug 422 of includes physically distinct components configured to perform the equivalent functions, respectively.
  • plug 422 includes a generally hemispherical portion 446 configured to seal proximal valve opening 420A, and an annular portion 448 configured to receive and/or couple to proximal and distal springs 424A, 424B.
  • annular portion 448 of plug 422 defines a proximal annular groove 450 A configured to receive a distal end of proximal spring 424 A.
  • annular portion of plug 422 may define a distal annular groove 450B configured to receive a proximal end of distal spring 424B.
  • Hemispherical portion 446 and annular portion 448 may be operatively coupled by a plurality of radial struts 452 defining gaps 454 therebetween for fluid and/or thrombus material to travel through while flow switch 410 is in the open configuration shown in FIG. 4A.
  • radial struts 452 may be formed from a substantially rigid material, such that hemispherical portion 446, annular portion 448, and radial struts 452 collectively define a structurally coherent unit.
  • radial struts 452 may be formed from a substantially elastic material, such that radial struts 452 define a biasing mechanism for plug 422, as described above with respect to plug 222.
  • radial struts 452 may include elastic bands that, in the absence of outside forces applied to hemispherical portion 446, suspend hemispherical portion 446 in a (distal) equilibrium position, defining the “open” configuration of flow switch 410.
  • annular portion 448 may be either fixed in place relative to internal cavity 414, or in other examples, may be entirely absent (e.g., radial struts 452 may extend between an interior surface of housing 412 and hemispherical portion 446. Additionally or alternatively, in such configurations, flow switch 410 may not include either or both of proximal and distal springs 424A, 424B, and radial struts 452 may provide the plug -biasing functionality alone.
  • FIG. 7 is a flow diagram of an example technique for using the aspiration systems and flow switches described herein.
  • the technique of FIG. 7 is described with reference to the various aspects of aspiration system 100 of FIG. 1 and flow switch 210 of FIGS. 2A-3 for illustrative purposes, however, such descriptions are not intended to be limiting.
  • the technique of FIG. 7 may be used with other aspiration systems and/or flow switches described herein, or aspiration system 100 and/or flow switch 210 of FIG. 1 may be used using techniques other than those described with reference to FIG. 7.
  • a clinician fluidically couples flow switch 210 to a suction source 102 and to the inner lumen of a catheter 108 (700).
  • the clinician may mechanically and fluidically connect vacuum tube 116 to a proximal opening 218A of flow switch 210.
  • the clinician may also mechanically and fluidically connect elongated body 112 of catheter 108 to distal opening 218B of flow switch 210, so as to define a continuous fluid flow pathway through the inner lumen of catheter 108, the internal cavity 214 of flow switch 210, and the inner lumen of vacuum tube 116.
  • the clinician Prior to or after coupling flow switch 210 to catheter 108 and suction source 102, the clinician introduces catheter 108 into vasculature of a patient (702) and navigates catheter 108 to a target treatment site within a patient. In some examples, the clinician navigates catheter 108 to the target site with the aid of a guidewire, guide catheter or another guide member.
  • control circuitry 120 controls suction source 102 to generate a suction force within the inner lumen of catheter 108 (704).
  • distal opening 114 of catheter 108 may initially be positioned near thrombus material, but may not be positioned against (e.g., occluded by) the thrombus material.
  • the suction force from suction source 102 may begin to aspirate a patient fluid, such as blood, into catheter 108, generating a proximal fluid flow through internal cavity 214 of flow switch 210.
  • the fluid flow may impart a drag force onto a distal-facing surface 222B of plug 222 within internal cavity 214.
  • plug 222 may translate proximally and seal proximal valve opening 220A, thereby restricting or preventing further fluid flow through flow switch 210.
  • the clinician may continue to manipulate distal opening 114 of catheter 108 until distal opening 114 is positioned against, and occluded by, thrombus material. At such time, the fluid flow into catheter 108 will be disrupted by the thrombus material at distal opening 114, and the fluid pressure on a distal side of plug 222 may begin to drop.
  • plug 222 may begin to equalize via leak channels 226.
  • the compression force (or tension forces in other examples) from springs 224 will distally bias plug 222 back toward the distal valve opening 220B, such that flow switch 210 reverts to an open configuration.
  • the technique of FIG. 7 further the clinician may proceed to aspirate the thrombus (706) and remove catheter 108 from the vasculature of the patient once the procedure is complete (708).
  • control circuitry 120 may be implemented, at least in part, in hardware, software, firmware or any combination thereof.
  • various aspects of the techniques may be implemented within one or more processors, including one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components, embodied in programmers, such as clinician or patient programmers, medical devices, or other devices.
  • Processing circuitry, control circuitry, and sensing circuitry, as well as other processors and controllers described herein, may be implemented at least in part as, or include, one or more executable applications, application modules, libraries, classes, methods, objects, routines, subroutines, firmware, and/or embedded code, for example.
  • analog circuits, components and circuit elements may be employed to construct one, some or all of the control circuitry 120, instead of or in addition to the partially or wholly digital hardware and/or software described herein. Accordingly, analog or digital hardware may be employed, or a combination of the two. Whether implemented in digital or analog form, or in a combination of the two, control circuitry 120 can comprise a timing circuit.
  • the functions described in this disclosure may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on, as one or more instructions or code, a computer-readable medium and executed by a hardware-based processing unit.
  • the computer-readable medium may be an article of manufacture including a non- transitory computer-readable storage medium encoded with instructions. Instructions embedded or encoded in an article of manufacture including a non-transitory computer- readable storage medium encoded, may cause one or more programmable processors, or other processors, to implement one or more of the techniques described herein, such as when instructions included or encoded in the non-transitory computer-readable storage medium are executed by the one or more processors.
  • Example non-transitory computer- readable storage media may include RAM, ROM, programmable ROM (PROM), erasable programmable ROM (EPROM), electronically erasable programmable ROM (EEPROM), flash memory, a hard disk, a compact disc ROM (CD-ROM), a floppy disk, a cassette, magnetic media, optical media, or any other computer readable storage devices or tangible computer readable media.
  • a computer-readable storage medium comprises non- transitory medium.
  • the term “non-transitory” may indicate that the storage medium is not embodied in a carrier wave or a propagated signal.
  • a non-transitory storage medium may store data that can, over time, change (e.g., in RAM or cache).
  • a flow switch includes: a housing defining an internal cavity and proximal and distal openings to the internal cavity, wherein the internal cavity is configured to receive an aspirated fluid flow from a catheter; and a plug disposed within the internal cavity and configured to: move proximally, in response to an abovethreshold drag force from the fluid flow applied to a distal-facing surface of the plug, to close the proximal opening; and move distally to open the proximal opening in response to an absence of the fluid flow within the internal cavity.
  • the flow switch further includes: a distal spring positioned between the distal-facing surface of the plug and an interior surface of the housing; and a proximal spring positioned between a proximal-facing surface of the plug and the interior surface of the housing, wherein the proximal and distal springs are configured to bias the plug distally away from the proximal opening in the absence of the aspirated fluid flow within the internal cavity.
  • the flow switch further includes an input mechanism configured to modify a compression or expansion force applied by the proximal spring or the distal spring to the plug to modify a magnitude of the drag force required move the plug proximally to close the proximal opening.
  • Clause 4 In some examples of the flow switch of clause 3, the input mechanism includes a threaded rotatable element.
  • Clause 5 In some examples of the flow switch of any of clauses 2 through 4, the internal cavity defines a fluid flow path, and an annular space oriented radially outward from the fluid flow path, wherein the proximal and distal springs are disposed within the annular space.
  • the housing further defines a plurality of leak channels extending from a distal cavity portion of the internal cavity distal to the plug, to a proximal cavity portion of the internal cavity proximal to the rounded plug, wherein the plurality of leak channels are configured to modulate a fluid-pressure differential between the proximal cavity portion and the distal cavity portion.
  • the flow switch further includes a selector switch configured to open or close different leak channels of the plurality of leak channels to modulate a time delay between a removal of the fluid flow within the internal cavity and a re-opening of the proximal opening by the plug.
  • the flow switch further includes an input mechanism configured to open or occlude at least one leak channel of the plurality of leak channels to modulate a time delay between a removal of the fluid flow within the internal cavity and a re-opening of the proximal opening by the plug.
  • the input mechanism comprises an adjustable needle valve and an external adjustment screw.
  • Clause 10 In some examples of the flow switch of any of clauses 6 through 9, the fluid-pressure differential is configured to retain the flow switch in a closed configuration by at least holding the plug proximally over the proximal opening.
  • Clause 11 In some examples of the flow switch of any of clauses 6 through
  • the plurality of leak channels is distributed circumferentially around a central longitudinal axis of the flow switch.
  • Clause 12 In some examples of the flow switch of any of clauses 1 through
  • the housing is configured to fluidically couple to proximal aspiration tubing at the proximal opening, and to fluidically couple to an elongated body of the catheter at the distal opening.
  • the plug includes a spherical plug.
  • Clause 14 In some examples of the flow switch of any of clauses 1 through 12, the plug includes a hemispherical plug.
  • the plug further includes an annular structure disposed radially outward from, and mechanically coupled to, the hemispherical plug, wherein the annular structure defines proximal and distal grooves configured to engage with proximal and distal springs, respectively.
  • the housing includes a proximal housing portion defining the proximal opening and a distal housing portion defining the distal opening, and wherein the flow switch further comprises an O-ring configured to fluidically seal the proximal housing portion to the distal housing portion.
  • the flow switch further includes a bypass mechanism configured to prevent the plug from moving proximally when the fluid flow is present within the internal cavity.
  • a method includes: fluidically coupling a proximal opening to an internal cavity of a flow switch to a distal end of aspiration tubing coupled to a suction source; fluidically coupling a distal opening to the internal cavity of the flow switch to a proximal end of an aspiration catheter, wherein the flow switch further includes a plug disposed within the internal cavity and configured to: move proximally, in response to an above-threshold drag force from the fluid flow applied to a distal-facing surface of the plug, to close the proximal opening; and move distally to open the proximal opening in response to an absence of the fluid flow within the internal cavity; introducing a distal portion of the catheter into vasculature of a patient; aspirating a thrombus from the vasculature of the patient via the catheter; and withdrawing the catheter from the vasculature of the patient.
  • a medical aspiration system includes: a suction source; aspiration tubing fluidically coupled to the suction source, wherein the aspiration tubing defines an inner lumen; and a flow switch fluidically coupled to the aspiration tubing, the flow switch includes a housing defining an internal cavity configured to receive an aspirated fluid flow from a catheter; and a proximal opening to the internal cavity, the proximal opening configured to fluidically connect to a distal end of the aspiration tubing; and a distal opening to the internal cavity, the distal opening configured to fluidically connect to the catheter; and a plug disposed within the internal cavity and configured to: move proximally, in response to an above-threshold drag force from the fluid flow applied to a distal-facing surface of the plug, to close the proximal opening; and move distally to open the proximal opening in response to an absence of the fluid flow within the internal cavity.
  • the flow switch further includes: a distal spring positioned between the distal -facing surface of the plug and an interior surface of the housing; and a proximal spring positioned between a proximal-facing surface of the plug and the interior surface of the housing, wherein the proximal and distal springs are configured to bias the plug distally away from the proximal opening in the absence of the aspirated fluid flow within the internal cavity.

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Abstract

Dans certains exemples, un système d'aspiration médicale comprend un commutateur d'écoulement (110) conçu pour se fermer passivement afin de limiter l'aspiration d'un fluide corporel à partir du corps d'un patient. Dans certains exemples, le commutateur d'écoulement (110) comprend un boîtier délimitant une cavité interne, et des ouvertures proximale et distale sur la cavité interne, la cavité interne étant conçue pour recevoir le fluide aspiré à partir d'un cathéter (108). Le commutateur d'écoulement comprend en outre un bouchon disposé à l'intérieur de la cavité interne et conçu pour se déplacer de manière proximale, en réponse à une force de résistance à l'écoulement supérieure à un seuil à partir d'un écoulement de fluide du fluide aspiré à l'intérieur de la cavité interne appliquée à une surface de face distale du bouchon, afin de fermer l'ouverture proximale ; et se déplacer de manière distale pour ouvrir l'ouverture proximale en réponse à une absence de l'écoulement de fluide à l'intérieur de la cavité interne.
PCT/IB2022/057167 2021-08-02 2022-08-02 Commutateur d'écoulement passif pour aspiration médicale WO2023012665A1 (fr)

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EP22757363.1A EP4380474A1 (fr) 2021-08-02 2022-08-02 Commutateur d'écoulement passif pour aspiration médicale
CN202280050208.7A CN117677351A (zh) 2021-08-02 2022-08-02 用于医疗抽吸的被动流量开关

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US202163228364P 2021-08-02 2021-08-02
US63/228,364 2021-08-02
US17/809,118 US20230031759A1 (en) 2021-08-02 2022-06-27 Passive flow switch for medical aspiration
US17/809,118 2022-06-27

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2121936A (en) * 1934-05-01 1938-06-28 Phillips Petroleum Co Combination excess flow and check valve
US3085589A (en) * 1960-06-06 1963-04-16 Asa D Sands Safety valve
US4030520A (en) * 1976-08-05 1977-06-21 Sands Asa D Ball-type safety valve
US20020092566A1 (en) * 2001-01-16 2002-07-18 Rhone Evan M. Safety valve with adjustable maximum flow shut off mechanism
US6579263B1 (en) * 2002-01-11 2003-06-17 Milton Chernack Method and apparatus for the delivery of contrast fluid to a patient
US20090032121A1 (en) * 2007-07-31 2009-02-05 Chon James Y Check Valve
US20170014617A1 (en) * 2015-07-15 2017-01-19 Bruce T. Huici Catheter
US20210220528A1 (en) * 2020-01-21 2021-07-22 Covidien Lp Medical aspiration

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2121936A (en) * 1934-05-01 1938-06-28 Phillips Petroleum Co Combination excess flow and check valve
US3085589A (en) * 1960-06-06 1963-04-16 Asa D Sands Safety valve
US4030520A (en) * 1976-08-05 1977-06-21 Sands Asa D Ball-type safety valve
US20020092566A1 (en) * 2001-01-16 2002-07-18 Rhone Evan M. Safety valve with adjustable maximum flow shut off mechanism
US6579263B1 (en) * 2002-01-11 2003-06-17 Milton Chernack Method and apparatus for the delivery of contrast fluid to a patient
US20090032121A1 (en) * 2007-07-31 2009-02-05 Chon James Y Check Valve
US20170014617A1 (en) * 2015-07-15 2017-01-19 Bruce T. Huici Catheter
US20210220528A1 (en) * 2020-01-21 2021-07-22 Covidien Lp Medical aspiration

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