Patent Description:
Briefly summarized, embodiments of the present invention are directed to a patency device for catheter assemblies and other elongate tubular devices used for establishing access to an interior body portion of a patient. The patency device establishes and/or preserves patency of one or more lumens defined by the catheter assembly by providing impulses of positive pressure to fluid disposed in the lumen of the catheter assembly.

In one embodiment, the patency device comprises a fluid reservoir configured to provide a fluid (or establish a fluid path) to at least one lumen of the catheter assembly, and a pressure input portion. The pressure input portion is configured to provide pressure for one or more impulses of positive pressure to a fluid disposed within the lumen. The impulses are configured to dislodge occlusions that may have formed in the lumen. A negative pressure can then be provided to the lumen to aspirate the occlusion and remove it from the catheter assembly.

These and other features of embodiments of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of embodiments of the invention as set forth hereinafter.

Reference will now be made to figures wherein like structures will be provided with like reference designations. It is understood that the drawings are diagrammatic and schematic representations of exemplary embodiments of the present invention, and are neither limiting nor necessarily drawn to scale.

For clarity it is to be understood that the word "proximal" refers to a direction relatively closer to a clinician using the device to be described herein, while the word "distal" refers to a direction relatively further from the clinician. For example, the end of a catheter placed within the body of a patient is considered a distal end of the catheter, while the catheter end remaining outside the body is a proximal end of the catheter. Also, the words "including," "has," and "having," as used herein, including the claims, shall have the same meaning as the word "comprising.

Embodiments of the present invention are generally directed to catheter assemblies and other elongate tubular devices used for establishing access to an interior body portion of a patient. A peripherally inserted central catheter ("PICC") is one example of such a catheter assembly. In particular, solutions and methods for establishing and preserving the patency of one or more lumens defined by the catheter assembly are disclosed. Examples of patency devices that may be employed are disclosed according to particular embodiments, discussed below.

Reference is first made to <FIG>, which generally depicts various details of a catheter assembly ("catheter"), generally designated at <NUM>, and a patency device, to be described further below, in accordance with one embodiment. As shown, the catheter <NUM> includes an elongate catheter tube <NUM> that defines a lumen <NUM> extending between a proximal end 12A and a distal end 12B of the catheter tube. A luer connector <NUM> or other suitable connector is included at the proximal end 12A of the catheter tube <NUM>. In other embodiments, the catheter can include a bifurcation hub at the proximal end of the catheter tube, with one or more extension legs proximally extending therefrom.

Though shown here as defining a single lumen <NUM>, the catheter <NUM> in other embodiments can define two or more lumens. Also, though shown as a PICC, the catheter in other embodiments can include other catheter types, such as dialysis, CVC, PIV, urinary, arterial, balloon catheters, etc. Thus, the discussion herein is not intended to be limiting.

<FIG> further shows details regarding a patency device <NUM> configured to operably connect on a temporary basis with the catheter <NUM> and provide patency to the catheter tube lumen <NUM>, according to one embodiment. Generally, the patency device <NUM> includes a fluid reservoir <NUM> that is configured, together with a pressure input portion <NUM>, to provide one or more relatively short-duration impulses, also referred to herein as positive pressure impulses, of high-pressure fluid to the lumen <NUM> of the catheter tube <NUM>. Such impulses, when performed periodically, are configured to prevent the formation of thrombus or other occlusion in the lumen <NUM>, especially at the distal end thereof. These short-duration, high pressure impulses can also be used to clear the lumen after occlusions have formed therein.

In greater detail, the pressure input portion <NUM> of the patency device <NUM> includes a mechanical input, such as a manual or motor-controlled plunger-type syringe, to impart pressure impulses to fluid contained in the fluid reservoir <NUM>. The fluid reservoir <NUM> is configured to hold an amount of fluid that can be directed into the lumen(s) <NUM> of the catheter tube <NUM> prior to or in conjunction with the pressure impulses produced by the pressure input portion <NUM>. In one embodiment and as seen below, the fluid reservoir <NUM> serves as a hydraulic accumulator to store pressurized fluid, produced by the pressure input portion <NUM>, before its release to the lumen(s) <NUM>.

It is noted that other types of pressure input portions can be utilized to provide high-pressure fluid impulses, including electrical and acoustic actuators, voice coil actuators, linear actuators, piezoelectric motors, vibrational drums and membrane, etc., for instance.

A catheter connector interface <NUM> defining a lumen <NUM> is included to enable the patency device <NUM> to operably connect to the luer connector <NUM> (or other portion) of the catheter <NUM> and provide a conduit through which the high pressure fluid can pass from the fluid reservoir <NUM> to the lumen(s) <NUM> of the catheter tube <NUM>. Note that in one embodiment the connector interface <NUM> is a sterile item to bridge between the non-sterile patency device <NUM> and the catheter <NUM>. In this way, the connector interface <NUM> can be manufactured as a disposable, sterile item, while the patency device <NUM> is reusable.

In operation, the patency device <NUM> emits periodic, relatively short-duration, relatively high-pressure bursts, or impulses, in the distal direction through the fluid-filled lumen <NUM> of the catheter tube <NUM>. These impulses are produced by the pressure input portion <NUM> in conjunction with the pressure portion <NUM> and transmitted through the lumen <NUM> of the patency device <NUM> to the catheter tube lumen <NUM> via the connector interface <NUM> luer connector <NUM>. It is appreciated that the pressure of the impulses, the impulse duration, the rest period between impulses, the frequency of successive impulses, etc., can be adjusted and varied according to the particular patency procedure being performed for the catheter <NUM>.

<FIG> depicts a graph of a pressure profile <NUM> (including fluid pressure vs. time) produced by the patency device <NUM> during operation. The pressure profile <NUM> includes time on the x-axis and impulse pressure on the y-axis for operation of the patency device <NUM>. As shown, the patency device <NUM> provides short-duration, relatively high-pressure impulses through the fluid present in the catheter tube lumen <NUM> interspersed by relatively longer rest periods <NUM> of negative baseline pressure provided to the catheter tube lumen. The negative baseline pressure present between impulses enables any occlusion dislodged by the impulses to be sucked proximally up the catheter tube lumen <NUM> and removed therefrom, thus preventing the dislodged occlusion from entering the bloodstream from the distal end 12B of the catheter tube <NUM>. Note that the rest periods in other embodiments can include a reduction to a neutral pressure or lower (but still positive) pressure or to varying pressures over time as may be desired.

<FIG> further shows that successive impulse peaks <NUM> that represent the short-duration high-pressure fluid impulses are shown on the graph of the pressure profile <NUM>. In the present embodiment, the pressure peaks <NUM> are each characterized by a rise-time phase of about <NUM> milliseconds, a holding high-pressure phase of about <NUM> milliseconds, and a pressure reduction phase of about <NUM> milliseconds. It is appreciated that these phases of the pressure peaks <NUM> can vary from the values given herein, and each pressure peak can vary in phase characteristics from previous and/or subsequent peaks. Also, the magnitude and duration of the impulses can vary from what is described herein and from one another.

In one embodiment, the pressure peaks <NUM> are modified by a controller of the patency device <NUM> so as to be customizable by the user. The rest periods <NUM> between the high-pressure fluid impulses (represented by the pressure peaks <NUM>) can also be varied in duration, baseline pressure, etc..

In the present embodiment, the maximum pressure achieved by the impulses is about <NUM> psi, though this can vary according to desired application, catheter lumen design, type or size of occlusion, catheter tube length, etc. In one embodiment, it is appreciated that the maximum pressure of the impulses may exceed the burst pressure strength rating of the catheter tube <NUM> in one embodiment, but as the impulses are of relatively short duration, no rupturing or failure of the catheter <NUM> occurs.

As mentioned above, the high-pressure fluid impulses travel from the patency device <NUM> and into the catheter <NUM> so as to travel down the fluid-filled lumen <NUM> of the catheter tube <NUM>. In one embodiment, the fluid filling the fluid path of the patency device and the catheter tube lumen <NUM> is a <NUM>% saline solution, though other fluids may also be acceptably used. Note that the use of other fluids can necessitate altering the impulse characteristics (e.g., impulse pressure, impulse duration, rest period duration, etc.). As noted above, the high-pressure fluid impulses impinge on an occlusion (such as a clot or fibrin sheath) or other obstruction that has formed in the lumen <NUM>, typically at or proximate the distal end 12B of the catheter tube <NUM>. The occlusion is dislodged by the high-pressure impulses, which are strong enough to dislodge the occlusion but are not of sufficient duration to push it out the distal end 12B of the catheter tube <NUM>. The subsequent negative pressure rest period following each impulse can act to prevent escape of the clot from the catheter tube <NUM>, in one embodiment. In addition, a suction process can be performed by the patency device <NUM> to withdraw the clot proximally from the catheter tube <NUM> and catheter <NUM> and into the patency device, where it may be disposed of. In this way, any clot or occlusion present in the catheter <NUM> can be acceptably removed.

<FIG> depicts the patency device <NUM> according to one embodiment. As shown, the patency device <NUM> includes a hydrostatic pump <NUM> that serves as the pressure input portion <NUM> for providing hydraulic pressure to fluid contained and maintained at pressure in a hydraulic accumulator ("accumulator") <NUM> that serves as the fluid reservoir <NUM>. A two-way, normally closed ("N. ") valve <NUM> is disposed at and operably connected at its fluid inlet to a fluid outlet of the accumulator <NUM> via a fluid line. A pressure transducer <NUM> is operably interposed between the fluid outlet of the N. valve <NUM> and the luer connector <NUM> or other suitable inlet to the catheter. As mentioned above, in this and other embodiments the connector interface <NUM> (<FIG>) can be used to operably connect the patency device <NUM> to the catheter <NUM>. Note that the fluid lines between the various components discussed herein can include tubing or other suitable modes for fluid transport.

A two-way, normally open ("N. ") valve <NUM> is interposed between the N. valve <NUM> and the transducer <NUM> via a fluid line connected to the N. valve fluid inlet. A vacuum input portion <NUM> for providing negative pressure in the patency device <NUM> is operably connected to the fluid outlet of the N. valve <NUM>. In the present embodiment, a syringe pump <NUM> serves as the vacuum input portion <NUM>, though other suitable components can also be employed, such as a vacuum pump. A controller <NUM> is operably connected to the aforementioned components of the patency device <NUM> to govern their operation. The controller <NUM> in one embodiment includes a power source, a printed circuit board including a processor, etc..

<FIG> depicts various details regarding a valve control assembly <NUM> associated with the N. valve <NUM> shown in the patency device <NUM> of <FIG>, according to one embodiment. As shown, the valve control assembly <NUM> includes a relay <NUM> and a power diode operably interconnected with the N. valve <NUM>. A power supply <NUM> is included for the N. valve <NUM>, as is a power supply <NUM> for the relay <NUM>. <FIG> shows a similar configuration for the valve control assembly <NUM> associated with the N. valve <NUM> of the patency device <NUM> of <FIG>, including a relay <NUM> and a power diode operably interconnected with the N. A power supply <NUM> is included for the N. valve <NUM>, as is a power supply <NUM> for the relay <NUM>. The valve control assemblies <NUM> for the N. valve <NUM> and the N. valve <NUM> assist in governing operation of the N. valves during operation of the patency device <NUM>. In the present embodiment, the N. valve <NUM> and the N. valve <NUM> are gate-valve types of valves, though it is appreciated that other suitable types of valves can be utilized. In another embodiment, the functionality of the N. valve <NUM> and the N. valve <NUM> can be combined into a single valve, such as a three-way valve, with the fluid lines being arranged so as to provide such an embodiment. In such a single valve embodiment, the single three-way valve is operated to alternately provide the impulses of positive pressures as well as the negative baseline pressures/negative impulses.

The patency device <NUM> of <FIG> is operably attached to luer connector <NUM> of the catheter <NUM> when a patency procedure (a procedure to clear the catheter tube lumen(s) <NUM> of an occlusion or to prevent formation thereof) is desired by a clinician or catheter user. In operation, the patency device <NUM> first provides fluid pressure via actuation - either manually or by automatic/motor modes - of the hydrostatic pump <NUM>. The pressurized fluid is received from the pump <NUM> by the accumulator <NUM>, which stores the fluid in a pressurized state until needed. valve <NUM> is maintained in an open state at the beginning and during the procedure to maintain a negative base pressure in the system except at those times when the N. valve <NUM> is opened to provide the fluid impulses. The controller <NUM> or other suitable component can control valve opening/closing.

The controller <NUM> determines the number, frequency, rest periods, etc., of the impulses to be delivered by the patency device <NUM> to the catheter tube lumen(s) <NUM>. valve <NUM> is opened and close repeatedly at predetermined time intervals to provide a series of fluid impulses from the accumulator, through the N. valve and into the lumen <NUM> of the catheter <NUM>. During each impulse when the N. C valve <NUM> is opened, the N. O valve <NUM> is shut so as to prevent impulse fluid from entering the N. valve and diverting to the syringe pump <NUM> instead of entering the catheter tube lumen <NUM> as desired. The impulses are propagated distally down the lumen <NUM>, which is fluid-filled prior to commencement of the patency operation so as to provide a propagation medium for the impulses.

Between each impulse and after the series of impulses has ended, the N. valve <NUM> closes and the N. valve <NUM> opens to provide a negative baseline pressure (provided by the syringe pump <NUM> or other suitable device) in the catheter tube lumen <NUM> and enable any occlusion dislodged by the impulses to be suctioned proximally out of the lumen, through the N. valve to the syringe pump <NUM>. An appropriate capture reservoir or the like can be operably connected to the syringe pump to provide for retention of occlusions and fluid if needed. The controller <NUM> is utilized to precisely control the opening/closing of the N. valve <NUM> and the N. valve <NUM> so as to provide the impulses and the negative baseline pressure to the lumen <NUM> as desired.

In one embodiment, it is appreciated that the baseline negative pressure periods existing between the positive pressure impulses can be replaced or supplemented with relatively short-duration impulses of negative pressure to further assist in occlusion dislodgement. Subsequent negative baseline pressure can then be used to remove the occlusion to the lumen <NUM>. In one embodiment, the response time of the valves <NUM> and <NUM> is sufficiently fast to enable the positive pressure impulses to be followed in quick succession by the negative baseline pressure or negative pressure impulse.

The pressure transducer <NUM> is utilized and controlled by the processor <NUM> to measure the pressure of the impulses delivered to the catheter tube lumen <NUM> by the patency device <NUM>. As mentioned, the pressure level of the impulses can be varied or determined according to a variety of factors, including catheter length, catheter lumen size, burst strength, impulse duration, rest period duration, other catheter configuration, etc. In one embodiment, the pressure of each impulse can be chosen from a range of from about <NUM> psi to about <NUM> psi, though other pressure below and above this are possible. Also, frequency of the impulses, or impulse frequency, can be set according to a predetermined pattern and can vary according to a number of factors such as those described immediately above and can range in one embodiment from about <NUM> to over about <NUM>, though other frequency ranges are also possible. In one embodiment, the impulse frequency is set to match the resonant frequency of the catheter <NUM> itself, thus enabling improved propagation of the impulses distally through the lumen <NUM>. In one example, for instance, the resonant frequency of a <NUM> Fr single lumen catheter assembly was found to be about <NUM> for catheter tube lengths of from about <NUM> to about <NUM>. The resonant frequency will vary according to a number of catheter characteristics. In one embodiment, for instance, resonant frequencies for various catheters vary from about <NUM> to about <NUM>, though other frequencies are possible.

In one embodiment, the impulse frequency is above about <NUM>, thus performing as an ultrasound impulse signal to dislodge lumen occlusions or maintain lumen patency. These ultrasonic signals are of sufficient frequency, intensity, and duty cycle as to dislodge the occlusion(s) present in the lumen(s) <NUM>. In one embodiment, the patency device <NUM> can include a an ultrasound module operably connectable to the luer connector <NUM> or extension leg of the catheter <NUM> and further includes an ultrasound transducer for providing ultrasonic impulses to the fluid-filled lumen <NUM>. The patency device <NUM> can further include ports to enable fluids or other substances to be infused into or aspired from the catheter tube lumen(s) <NUM>, such as antimicrobial agents, etc..

Note that the patency device <NUM> is either externally powered or can include its own power source, such as a battery. Note further that in one embodiment that the controller <NUM> can enable customization of the characteristics of the impulses, rest periods, baseline pressure, etc. by the user.

It is appreciated that periodic use of the patency devices described herein can also serve to prevent the formation of an occlusion by preventing initial adherence and growth of the occlusion in the first place, as mentioned herein. In one embodiment, the patency device is self-operating, thus serving as a passive solution to preventing occlusions.

Note that in one embodiment a pressure regulator can be employed to provide and/or maintain pressurized fluid in the patency device <NUM>. Note also that it is appreciated that adjustments may be made to the pressure of the impulses to compensate for pressure loss/attenuation as a function of the distance the impulse travels distally through the catheter tube lumen <NUM>.

In light of the above, it is appreciated that in one embodiment, a method (which is not a part of the invention) for providing patency to at the lumen(s) <NUM> the catheter assembly <NUM> comprises disposing a fluid in the lumen of the catheter tube <NUM> of the catheter; and propagating a plurality of impulses of positive pressure through the fluid disposed in the lumen, noting that the impulses are propagated in a predetermined pattern.

The patency device of <FIG> replaces the gate valve-type of valves with tubing pinch valves for the N. C valve <NUM> and the N. valve <NUM>. Such valves operate by pinching off a portion of the tubing that comprises the fluid lines, such as the illustrated high pressure tubing <NUM> proximate the N. pinch valve <NUM>, so as to stop fluid flow therethrough. The valve releases the pinch-off of the tubing to enable fluid flow anew therethrough. These and other valve types are therefore contemplated.

<FIG> depicts details of the patency device <NUM> according to another embodiment, wherein the pressure input portion <NUM> includes an actuator, such as a voice coil actuator <NUM> configured to provide mechanical movement for the formation of the desired fluid pressure impulses. A servo drive <NUM> is operably connected to the voice coil actuator <NUM> to assist in actuator function. A piston <NUM> (or plunger or the like) is operably connected to the voice coil actuator <NUM>, which in turn is operably connected to the fluid reservoir <NUM>, here a fluid-containing syringe <NUM>. The syringe <NUM> in the present embodiment is a high pressure syringe. The piston <NUM> is sized to be received within a proximal end of the syringe <NUM> so as to enable the piston to transfer the mechanical movements of the voice coil actuator to the fluid present in the syringe to create the desired impulses. Impulses produced in the fluid of the syringe <NUM> are forwarded past a valve <NUM> and into the lumen <NUM> of the catheter tube <NUM>. A hub adapter <NUM> is included in the present embodiment to enable the valve <NUM> to operably connect to the catheter <NUM>.

The valve <NUM> is operable, such as by <NUM> controller, to selectively open to enable the impulses produced by the aforementioned components to pass through to the catheter lumen <NUM>. At all other times during a patency procedure, the valve <NUM> is switched to enable a negative baseline pressure to be imparted to the catheter lumen <NUM> via the syringe pump <NUM> in manner similar to embodiments discussed above. In one embodiment, pressure of the impulses produced by the patency device <NUM> of <FIG> are measured from about <NUM> psi to more than about <NUM> psi, though this can vary according to system design.

<FIG> depicts details of the patency device <NUM> according to another embodiment, wherein the pressure input portion <NUM> includes a wave generator <NUM>, such as a loudspeaker, to produce energy for the formation of the desired fluid impulses. A signal generator <NUM> produces voltage waveforms, or driving signals, to actuate the wave generator in a desired pattern for the impulses, the signals of the signal generator being amplified by an amplifier <NUM>. In one embodiment, pressure of the impulses produced by the patency device <NUM> of <FIG> are measured at about <NUM> psi or less, though this can vary according to system design.

A piston, such as a plunger, is operably connected to the movable cone of the loudspeaker of the wave generator <NUM> is received within the fluid-containing syringe <NUM>, serving as the fluid reservoir <NUM>. Operation of the loudspeaker moves the cone thereof in accordance with the driving signals received and amplified by the signal generator <NUM> and amplifier <NUM>, which in turn moves the plunger in accordance with the driving signals. The fluid contained in syringe <NUM> is moved by the plunger, which produces the desired fluid impulses that are propagated distally through the lumen <NUM> of the catheter <NUM> via the hub adapter <NUM>. In one embodiment, the impulses produced by the patency device of <FIG> are in a frequency range of from about <NUM> to about <NUM>, though a variety of other frequencies are possible.

The embodiments of the patency device <NUM> shown and described in connection with <FIG>, <FIG>, <FIG> are therefore representative of a multitude of a variety of patency devices that can be employed to provide fluid impulses for the dislodgement of occlusive material within the lumen of a catheter and/or to maintain the patency of the lumen, free from occlusions.

<FIG> depict various operation cycles for the positive pressure impulses produced by the present patency device, such as the patency device <NUM> shown in <FIG>, for instance. <FIG> shows a pulse profile <NUM> including a continuous series of equal (in terms of energy, pressure) impulses delivered to the catheter tube lumen <NUM> (<FIG>) at a set impulse frequency and returning to a baseline pressure <NUM> before starting the next impulse. The frequency can be any one or more of a variety of impulse frequencies, including ultrasonic frequencies (e.g., above <NUM>).

In <FIG>, a series of groups of impulses is shown, wherein groups of impulses are separated by rest periods <NUM> of nominal baseline pressure <NUM>, such as a low positive pressure, which pattern is useful for when no occlusion is present but impulses are used to keep the lumen <NUM> patent.

In <FIG>, a series of groups of impulses is shown, wherein groups of impulses are separated by rest periods <NUM> of negative baseline pressure <NUM> to enable aspiration from the catheter <NUM> of any occlusions dislodged by the impulses, as discussed further above. In these and the other examples herein, note that the number of impulses in each group can vary according to user desire and/or a pre-set predetermined pattern, as can the pressure, frequency, etc. Note that frequency use of the patency device <NUM> can vary from continuously, hourly, daily, weekly, occasionally, etc., depending on whether the intended use is prophylactic or corrective, the amount of occlusion present, etc..

Claim 1:
A patency device (<NUM>) for providing patency to at least one lumen (<NUM>) of a catheter assembly (<NUM>), the patency device (<NUM>) comprising:
a fluid reservoir (<NUM>) configured to provide a fluid path to the at least one lumen (<NUM>) of the catheter assembly (<NUM>);
a pressure input portion (<NUM>) configured to provide pressure for at least one impulse of positive pressure to a fluid disposed within the at least one lumen (<NUM>),
wherein the device further comprises an interface portion (<NUM>) configured to operably connect the patency device (<NUM>) to the at least one lumen (<NUM>),
characterised in that, the interface portion (<NUM>) is disposable and provides a sterile barrier between the catheter assembly (<NUM>) and the patency device (<NUM>).