Patent Description:
Electrical stimulation of nerves is widely applied in the treatment of a range of conditions and may be applied to control muscle activity or to generate sensations. Muscles and nerves may be stimulated by placing electrodes in, around, or near the muscles and nerves and by activating the electrodes by means of an implanted or external source of energy (e.g. electricity).

The diaphragm muscle provides important functions for respiration. The phrenic nerves normally transmit signals from the brain to cause the contractions of the diaphragm muscle necessary for breathing. However, various conditions can prevent appropriate signals from being delivered to the phrenic nerves. These include:.

These conditions affect a significant number of people.

Intubation and positive pressure mechanical ventilation (MV) may be used for periods of several hours or several days, sometimes weeks, to help critically ill patients breathe while in intensive care units (ICU). Some patients may be unable to regain voluntary breathing and thus require prolonged or permanent mechanical ventilation. Although mechanical ventilation can be initially lifesaving, it has a range of significant problems and/or side effects. Mechanical ventilation:.

A patient who is sedated and connected to a mechanical ventilator cannot breathe normally because the central neural drive to the diaphragm and accessory respiratory muscles is suppressed. Inactivity leads to muscle disuse atrophy and an overall decline in well-being. Diaphragm muscle atrophy occurs rapidly and can be a serious problem to the patient. According to a published study in organ donor patients (<NPL>) after only <NUM> to <NUM> hours of mechanical ventilation, all diaphragm muscle fibers had shrunk on average by <NUM>-<NUM>%. Muscle fiber atrophy results in muscle weakness and increased fatigability. Therefore, ventilator-induced diaphragm atrophy could cause a patient to become ventilator-dependent. It has been estimated that over <NUM>,<NUM> patients will be ventilator dependent and require prolonged mechanical ventilation by the year <NUM> (<NPL>).

It may also be necessary during MV to deliver or remove one or more fluids or to obtain sensor readings from within the patient. Smaller patients, such as, for example, neonates, may require smaller medical instruments to perform the aforementioned procedures. Additionally, as with any medical procedure, the risk of injury to the patient increases with the length and complexity of the medical procedure. <CIT> describes an apparatus and methods for assisted breathing by transvascular nerve stimulation.

There remains a need for cost-effective, practical, surgically simple and minimally invasive apparatus that may be applied to stimulate breathing, deliver treatment, and perform tests. There is also a need for apparatus for facilitating patients on MV to regain the capacity to breathe naturally and to be weaned from MV.

Embodiments of the present disclosure relate to, among other things, medical apparatus for nerve stimulation. Specific embodiments provide apparatus for stimulating breathing by trans-vascular electrical stimulation of nerves. Each of the embodiments disclosed herein may include one or more of the features described in connection with any of the other disclosed embodiments.

In one embodiment, a catheter is defined in claim <NUM>.

The catheter may further include one or more of the following features. The lumen may be a groove or recessed channel exposed along a portion of the circumference of the body along at least a portion of the length of the body, and the groove may be at least partially covered by an outer layer. The ribbon cable may include a plurality of corrugations. The catheter may also include at least one filler positioned within at least a portion of the corrugations. The corrugations may be positioned radially inward of at least one electrode. The catheter may also include at least one fluid lumen and a guide wire lumen.

Further, the catheter may include a connector feed and an application specific integrated circuit ("ASIC") radially inward of the outer layer. The ASIC may connect the connector feed to the ribbon cable. The ribbon cable may include several, for example three, branches of ribbon cable, and the at least one longitudinal lumen may include three longitudinal lumens spaced circumferentially around an exterior of the body and radially inward of the outer layer. In this example, the three branches may extend distally from the ASIC, and each of the three branches may connect to at least one electrode through a corresponding longitudinal lumen. One branch of the three branches may include at least one lead that electrically connects at least one proximal electrode and at least one other lead that electrically connects at least one distal electrode. The plurality of apertures may include a plurality of proximal apertures and a plurality of distal apertures. The proximal apertures may include two longitudinally extending rows, and the distal apertures may include two longitudinally extending rows. One row of proximal apertures may be circumferentially aligned with one row of distal apertures. The ribbon cable may be electrically connected to at least one electrode via a connection and an electrode coupler, and the electrode coupler may longitudinally overlap with the ribbon cable and be positioned radially inward of a portion of the electrode. Further possible features are defined in dependent claims <NUM> and <NUM>.

In another alternative or additional embodiment, the catheter may include an outer layer defining a plurality of apertures therethrough, and a body radially within the outer layer. The catheter may also include a radial extension, extending helically around and radially outward from the body and within the outer layer, as well as a ribbon cable coupled to a plurality of electrodes. The ribbon cable may extend around an exterior of the body between portions of the radial extension, with each electrode of the plurality of electrodes electrically exposed through an aperture of the plurality of apertures, the apertures in this case being formed in an outer insulating layer over the electrodes.

The catheter may further include one or more of the following features. The plurality of electrodes may be coupled to the ribbon cable at approximately a <NUM> degree angle relative to a longitudinal axis of the ribbon cable. The catheter may include at least one ASIC positioned radially inward of the outer layer, and the at least one ASIC may electrically connect the ribbon cable to at least one of the plurality of electrodes. The body may include at least one groove exposed along a circumference of the body along at least a portion of the length of the body, and the at least one ASIC may be positioned within the at least one groove. The catheter may include at least one ASIC for each of the plurality of electrodes, and each ASIC may electrically connect the ribbon cable to the corresponding electrode. The catheter may include a conductive liner positioned over or within the apertures.

In another alternative or additional embodiment, the catheter may include an outer layer or sleeve. The outer layer may include first and second longitudinally extending rows of distal apertures in the outer layer, and the outer layer and/or the catheter may also include a first radiopaque feature for confirming an orientation of the first row of distal apertures relative to the second row of distal apertures.

The catheter may further include one or more of the following features. The catheter may further include first and second longitudinally extending rows of proximal apertures in the outer layer. The outer layer may include a second radiopaque feature for confirming an orientation of the first row of proximal apertures relative to the second row of proximal apertures. The first row of proximal apertures may be circumferentially aligned with one of either the first row of distal apertures or the second row of distal apertures. The second row of proximal apertures may be circumferentially offset from both the first row of distal apertures and the second row of distal apertures. The second radiopaque feature may include a radiopaque marker positioned circumferentially opposite to a line extending between the first and second rows of proximal apertures. The first radiopaque feature may be at a distal portion of the outer layer, and the second radiopaque feature may be at a proximal portion of the outer layer. The catheter may further include a hub, and the hub may include an orientation feature. The hub may also include a port configured to couple the hub to a proximal portion of the catheter in a particular orientation. The catheter may further include the features of any of dependent claims <NUM> to <NUM>.

Further aspects of the disclosures and features of example embodiments are illustrated in the appended drawings and/or described in the text of this specification and/or described in the accompanying claims.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate non-limiting embodiments of the present disclosure and together with the description serve to explain the principles of the disclosure.

Throughout the following description, specific details are set forth to provide a more thorough understanding to persons skilled in the art. The following description of examples of the technology is not intended to be exhaustive or to limit the system to the precise forms of any example embodiment. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

Reference will now be made in detail to examples of the present disclosure described above and illustrated in the accompanying drawings.

The terms "proximal" and "distal" are used herein to refer to the relative positions of the components of an exemplary medical device or insertion device. When used herein, "proximal" refers to a position relatively closer to the exterior of the body or closer to an operator using the medical device or insertion device. In contrast, "distal" refers to a position relatively further away from the operator using the medical device or insertion device, or closer to the interior of the body.

In general, embodiments of this disclosure relate to medical devices for electrically stimulating a patient's nerves. In one embodiment, the patient's nerves may be stimulated to activate the diaphragm to restore or control breathing.

The medical devices described herein may include several components, including a catheter having a tubular member and one or more electrode assemblies, a signal generator to provide stimulation energy to the electrode assemblies, and one or more sensors to sense the condition of the patient and adjust the stimulation signals. The medical devices may further include a steering mechanism. Various embodiments of catheters are disclosed, including windowed catheters, multi-lumen catheters, and radiopaque catheters. In addition, various embodiments of electrode assemblies are disclosed, which may be used alone, in combination with other electrode assemblies, and with any of the disclosed tubular members that form the outer portion of the catheters.

The different embodiments of the various medical device components (e.g., electrode assemblies, steering mechanisms, etc.) may be combined and used together in any logical arrangement. Furthermore, individual features or elements of any described embodiment may be combined with or used in connection with the individual features or elements of other embodiments. The various embodiments may further be used in different contexts than those specifically described herein. For example, the disclosed electrode structures may be combined or used in combination with various deployment systems known in the art for various diagnostic and/or therapeutic applications.

During use, the medical devices (e.g., a catheter with one or more electrode assemblies) may be inserted into a patient's blood vessels such that the electrode assemblies are near the patient's nerves. The electrode assemblies may then be used for transvascular electrical stimulation of the patient's nerves. The disclosed devices may be optimized for rapid, temporary deployment in a patient and easy removal from the patient. The disclosed devices may be used, for example, for restoring breathing, treating conditions such as disuse muscle atrophy and chronic pain, or for any other procedures involving nerve stimulation. The disclosed devices may be used to treat acute or chronic conditions.

<FIG> illustrates a medical system <NUM> that includes a catheter <NUM> including a plurality of lumens and having two proximal electrode assemblies <NUM> and two distal electrode assemblies <NUM>. The electrode assemblies <NUM> and <NUM> may be positioned on or within a tubular member or catheter body of catheter <NUM>. Catheter <NUM> may be positioned within a patient through the patient's external or internal jugular veins <NUM>, brachiocephalic veins <NUM>, superior vena cava <NUM>, brachial vein (not shown), radial vein (not shown), and/or left subclavian vein <NUM> such that the proximal electrode assemblies <NUM> are directed towards the left phrenic nerve <NUM>, and the distal electrode assemblies <NUM> are directed laterally towards the right phrenic nerve <NUM>. As such, when positioned, catheter <NUM> may receive signals from a control unit <NUM> and, using electrode assemblies <NUM> and <NUM>, stimulate the left phrenic nerve <NUM> and/or the right phrenic nerve <NUM>.

Catheter <NUM> may further include a manifold <NUM> that extends external to the patient. Electrical cable <NUM> and pigtail lumen <NUM> extend from manifold <NUM>. Cable <NUM> and pigtail lumen <NUM> may include cable connectors <NUM> and <NUM> to connect external elements, and cable <NUM> may be coupled to electrical control unit <NUM> via cable connector <NUM>. The cables <NUM> and <NUM> may be formed of electrical leads (not shown) that connect to electrode assemblies <NUM> and <NUM>. Cable connectors <NUM> and <NUM> may be attached (e.g. by solder, crimp, PCB, etc.) to the cables <NUM> and <NUM>, and one or both of cable connectors <NUM> and <NUM> may include a threading <NUM> (as shown in <FIG> and <FIG>). Alternatively or additionally, one or both of cable connectors <NUM> and <NUM> may include a push-to-pull compression fitting or a slip-lock fitting (not shown). Control unit <NUM> and other elements may be electronically connected to the components within catheter <NUM> to both send and receive signals and/or data to selectively stimulate electrode assemblies <NUM>, <NUM> and/or monitor the patient and any response to the stimulation. Alternatively or additionally, cables <NUM> and <NUM> may include one or more lumens or fluid lines that connect to one or more internal lumens in catheter <NUM>, and cable connectors <NUM> and <NUM> may form sealed connections with a fluid port or other source. Catheter <NUM> may also include an atraumatic distal tip <NUM>.

As shown in <FIG>, catheter <NUM> may include two axially extending rows of proximal apertures or windows <NUM>. Each axially extending row includes proximal windows <NUM> positioned at the same circumferential position around the exterior of catheter <NUM>, but at different axial positions along the exterior of catheter <NUM>. The two rows of proximal windows <NUM> may be substantially aligned. For instance, as illustrated in <FIG>, one proximal window <NUM> of a first row is located at the same axial position as a window of a second row, but at a different circumferential position around the exterior of the catheter <NUM>. When positioned in a patient, the two rows of proximal windows <NUM> may be substantially posterior facing, and at least one proximal window <NUM> may face, abut or be positioned in the vicinity of the left phrenic nerve <NUM>.

Catheter <NUM> may also include two axially extending rows of distal apertures or windows <NUM>. Again, each axially extending row includes distal windows <NUM> positioned at the same circumferential position around the exterior of catheter <NUM>, but at different axial positions along the exterior of catheter <NUM>. The two rows of distal windows <NUM> may be unaligned such that one distal window <NUM> of a first row is axially between two distal windows <NUM> of a second row. For instance, as illustrated in <FIG>, one distal window <NUM> of a first row is located at a different axial position and at a different circumferential position around the exterior of the catheter <NUM> than a window of the second row. When positioned in a patient, the two rows of distal windows <NUM> may be substantially laterally facing (to the patient's right), and at least one distal window <NUM> may face, abut, or be positioned in the vicinity of the right phrenic nerve <NUM>. Therefore, in the example shown in <FIG>, when viewed ventrally, the two unaligned rows of three distal windows <NUM> may appear as one row of six distal windows <NUM>, because one row is anterior facing (shown as dark windows) and one row is posterior facing (shown as lighter windows).

The proximal windows <NUM> and the distal windows <NUM> may be positioned on catheter <NUM> such that one row of proximal windows <NUM> is circumferentially aligned (i.e., the same circumferential position but different axial position) with one row of distal windows <NUM>, but another row of proximal windows <NUM> and another row of distal windows <NUM> are each circumferentially offset from the aligned rows on the catheter <NUM>. Proximal electrode assemblies <NUM> may include individual proximal electrodes <NUM> that are positioned to be aligned with (e.g., radially inward of and underneath) proximal windows <NUM>, and distal electrode assemblies <NUM> may include individual distal electrodes <NUM> that are positioned to be aligned with (e.g., radially inward of and underneath) distal windows <NUM>. Windows <NUM>, <NUM> may expose electrodes <NUM>, <NUM>, allowing for a conductive path between sets or pairs of electrodes <NUM>, <NUM> and surrounding tissue, including the blood vessel lumen in which catheter <NUM> is inserted.

In one embodiment illustrated in <FIG>, catheter <NUM> includes twelve proximal windows <NUM> (two rows of six windows <NUM>) and six distal windows <NUM> (two rows of three windows <NUM>). However, in other embodiments, the catheter <NUM> may include fewer or more rows and numbers of proximal or distal windows <NUM>. For example, in other embodiments, the catheter <NUM> may include two, four, eight, ten, twelve, or more proximal windows <NUM> arranged in one, two, three, or more rows, and/or two, four, six, eight, ten, twelve or more distal windows <NUM> arranged in one, two, three, or more rows. The proximal windows <NUM> and distal windows <NUM> may be configured in pairs such that the catheter <NUM> has an even number of proximal windows <NUM> and an even number of distal windows <NUM>. However, the number of windows <NUM> or <NUM> may also be an odd number.

The windows <NUM>, <NUM> may be cut (e.g. by a laser, manual skive, drill, punch, etc.) through the exterior wall of catheter <NUM>, or the windows <NUM>, <NUM> may be formed by any other suitable method, such as during an extrusion process. <NUM>-D printing, or other manufacturing process. The windows <NUM>, <NUM> may extend along the longitudinal axis of catheter <NUM>, or they may have a rectangular, oval, square, or any other shape. The windows <NUM>, <NUM> may be apertures configured to allow electrical signals to travel from an interior lumen of the catheter <NUM> to the exterior of the catheter <NUM>. In an additional or alternative embodiment, the windows <NUM>, <NUM> may be covered by a material that allows electrical signals to pass through. As can be seen in the figures, the proximal windows <NUM> may be rotationally offset from the distal windows <NUM>. In other words, in one embodiment, a straight line drawn proximally through a row of distal windows <NUM> does not necessarily pass through a row of proximal windows <NUM>. In other embodiments, one or more rows of proximal windows <NUM> may be aligned with a corresponding row of distal windows <NUM>. Furthermore, the characteristics of the proximal windows <NUM> may differ from the characteristics of the distal windows <NUM>.

The dimensions of catheter <NUM> may be customized in accordance with the anatomy of a particular patient (e.g., different sizes of humans, pigs, chimpanzees, etc.). However, in some embodiments, the length of the section of the catheter <NUM> that includes the proximal windows <NUM> may be <NUM> or less, between <NUM>-<NUM>, or between <NUM>-<NUM>. The distance between two adjacent proximal windows <NUM> (whether the windows are circumferentially adjacent or longitudinally adjacent on the same row of windows) may be <NUM> or less, <NUM> or less, may be around <NUM>, or may be less than <NUM>. The length of the section of the catheter <NUM> that includes the distal windows <NUM> may be <NUM> or less, between <NUM>-<NUM>, or between <NUM>-<NUM>. The distance between two adjacent distal windows <NUM> (whether circumferentially adjacent or longitudinally adjacent on the same row of windows) may be <NUM> or less, <NUM> or less, may be around <NUM>, or may be less than <NUM>. The length of the section of the catheter <NUM> between proximal windows <NUM> and distal windows <NUM>, which may be free of windows, may be <NUM> or less, <NUM> or less, or <NUM> or less. The windows <NUM>, <NUM> may have a length of <NUM> or less, <NUM> or less, <NUM> or less, <NUM> or less, <NUM> or less, or <NUM> or less. In one embodiment, the windows <NUM>, <NUM> may have a length that is less than the length of corresponding electrodes that are electrically exposed through the windows. These catheter dimensions are exemplary only, and the catheter <NUM> may have dimensions that vary from the above ranges and specific measurements. For neonatal applications, the distance between the distal electrodes and the proximal electrodes may be very small, perhaps less than <NUM> or even less than <NUM>. Alternatively, in this situation, a signal electrode array may contain electrode combinations which suitably serve to stimulate both the left phrenic nerve and the right phrenic nerve.

Additionally, catheter <NUM> may include windows <NUM>, <NUM> in different configurations than discussed above. For example, catheter <NUM> may include more than two longitudinally extending rows of proximal windows <NUM> positioned at different circumferential positions. As such, catheter <NUM> may provide for more than two proximal electrode assemblies <NUM>, or for two proximal electrode assemblies <NUM> to be positioned in different configurations in catheter <NUM>. Alternatively or additionally, catheter <NUM> may be rotatable about the longitudinal axis such that windows <NUM>, <NUM> at various circumferential positions may be positioned in different positions relative to the targeted nerves. Varying configurations may provide for various stimulation patterns with which catheter <NUM> may stimulate targeted nerves.

In one embodiment, medical system <NUM> may be assembled by positioning proximal and distal electrode assemblies <NUM>, <NUM> within the outer, windowed tubular member of catheter <NUM> such that proximal electrodes <NUM> are at least partially exposed through proximal windows <NUM> and distal electrodes <NUM> are at least partially exposed through distal windows <NUM>. The proximal electrode assemblies <NUM> may include the proximal electrodes <NUM> arranged and oriented to most effectively stimulate a nerve extending at transverse or right angles to the catheter <NUM> (e.g., the left phrenic nerve <NUM> in <FIG> and <FIG>), and the distal electrode assemblies <NUM> may include the distal electrodes <NUM> arranged and oriented to most effectively stimulate a nerve extending approximately parallel to the catheter <NUM> (e.g., the right phrenic nerve <NUM> in <FIG> and <FIG>). In an additional or alternative embodiment, the proximal electrode assemblies <NUM> may include proximal electrodes <NUM> arranged and oriented to most effectively stimulate a nerve extending approximately parallel to the catheter <NUM>, and the distal electrode assemblies <NUM> may include distal electrodes <NUM> arranged and oriented to most effectively stimulate a nerve extending at transverse or right angles to the catheter <NUM>. In the embodiments described above, the distal electrode assemblies <NUM> have been placed in a more distal location along catheter <NUM> than the proximal electrode assemblies <NUM>. However, in other embodiments, the electrode assemblies <NUM>, <NUM> may be rearranged within the catheter <NUM>, and the proximal windows <NUM> and distal windows <NUM> of the catheter <NUM> may be configured to accommodate the alternative placement of the electrode assemblies <NUM>, <NUM>.

Distal tip <NUM> may be a tapered distal end portion of catheter <NUM>. Distal tip <NUM> may be open at the distal end to allow a guide wire <NUM> to pass through and distally beyond catheter <NUM>. Distal tip <NUM> may have a smaller circumference than the body of catheter <NUM>. Distal tip <NUM> may be softer than other portions of catheter <NUM>, be atraumatic, and have rounded edges. Distal tip <NUM> may be made of an aliphatic polyester-based thermoplastic polyurethane with a portion, for example, of <NUM>% barium sulfate. Distal tip <NUM> may be formed and/or coupled to a remainder of catheter <NUM> by melting an extruded tube of thermoplastic polyurethane in a mold using, for example, an induction heater.

The medical system <NUM> may be used to rhythmically activate the diaphragm by inserting the catheter <NUM>, with one or more electrode assemblies <NUM> and <NUM>, percutaneously into central veins of a patient, as shown by <FIG>. Guide wire <NUM> may be used to position catheter <NUM> within a patient. For example, the Seldinger technique may be used, in which guide wire <NUM> is inserted through a hypodermic needle into a vein. As in the example shown in <FIG> and <FIG>, the catheter <NUM> may be inserted into the left subclavian vein <NUM> and advanced into the superior vena cava <NUM>. In an unillustrated example, catheter <NUM> may be inserted into the left jugular vein and advanced into the superior vena cava <NUM>. In either example, catheter <NUM> may be inserted in a minimally-invasive way and may be temporarily placed into, and thus removable from, the patient. The distal tip <NUM> of the catheter <NUM> may then be passed over the guide wire <NUM> and advanced into the vein. The shape and mechanical properties of the catheter <NUM> may be designed to urge the catheter <NUM> to gently hug the vein wall in regions adjacent to the right and left phrenic nerves, as shown in <FIG>. The guide wire <NUM> may also be positioned such that it is adjacent to the right and left phrenic nerves before the distal tip of the catheter <NUM> is passed over the guide wire <NUM>. When the catheter <NUM> is positioned, the guide wire <NUM> may extend distal to the catheter <NUM> from distal tip <NUM>, through an internal lumen in catheter <NUM>, through pigtail lumen <NUM>, and proximally out of a cable connector <NUM>, as shown in <FIG>.

Once the catheter <NUM> is fully inserted into the patient, various electrodes or electrode combinations can be tested to locate nerves of interest and to determine which electrodes most effectively stimulate the nerves of interest. For example, in one embodiment, testing may be done to locate the right phrenic nerve <NUM> and to determine which group of distal electrodes <NUM> in the distal electrode assemblies <NUM> most effectively stimulate the right phrenic nerve <NUM>. Similarly, testing may be done to locate the left phrenic nerve <NUM> and to determine which group of proximal electrodes <NUM> in the proximal electrode assemblies <NUM> most effectively stimulate the left phrenic nerve <NUM>. This testing and nerve location may be controlled and/or monitored via control unit <NUM>, which may include testing programming and/or applications. For example, control unit <NUM> may test the electrodes and electrode combinations to determine which pair of bipolar distal electrodes <NUM> most effectively stimulate the right phrenic nerve <NUM>, and which pair of bipolar proximal electrodes <NUM> most effectively stimulate the left phrenic nerve <NUM>. Alternatively, control unit <NUM> may test the electrodes or electrode combinations to determine which tripolar or multipolar electrode combinations most effectively stimulate the phrenic nerves (for example, one cathode electrode and two anode electrodes, two cathode electrodes and one anode electrode, one cathode electrode and three anode electrodes, three cathode electrodes and one anode electrode, two cathode electrodes and two anode electrodes, one cathode electrode and four anode electrodes, four cathode electrodes and one anode electrode, one cathode electrode and five anode electrodes, five cathode electrodes and one anode electrode, etc.).

As a non-limiting example, testing could involve the use of a signal generator to systematically send electrical impulses to selected electrodes. By observing the patient's condition or by using sensors (either within or separate from the catheter <NUM>), the ideal stimulation electrodes may be identified. Electrodes may serve as both stimulating electrodes and as sensing electrodes, and the medical system <NUM> may be integrated into a mechanical ventilator, which can be used to sense the patient's condition. Moreover, for example, control unit <NUM> may be programmed and/or activated to (a) select a first stimulation group of electrodes from the proximal electrode assemblies <NUM> to stimulate the left phrenic nerve <NUM>, (b) select a second stimulation group of electrodes from the distal electrode assemblies <NUM> to stimulate the right phrenic nerve <NUM>, (c) select a first stimulation current for the first stimulation group of electrodes to stimulate the left phrenic nerve <NUM>, and (d) select a second stimulation current for the second stimulation group of electrodes to stimulate the right phrenic nerve <NUM>. The selection of electrodes and current level may be pre-programmed or input based on the patient's characteristics, or the control unit <NUM> may test different electrode groups and current levels and monitor the patient's response to determine the electrode pairs and current levels. For example, the monitoring of the patient's response may include manual palpitation of the thoracic region, sensors to sense the movement of the patient's chest wall (e.g., accelerometers, optical devices, camera based sensors, etc.), airflow sensors, airway pressure sensors, central venous pressure sensors, etc. Control unit <NUM> may include a stimulation signal generator to generate the stimulation signals and to selectively transmit the generated signals to the selected electrodes.

Once ideal electrode combinations (e.g. pair, triplets, etc.) have been identified, an electrical potential may be created between a pair of selected bipolar electrodes, for example, a pair of proximal electrodes <NUM> each aligning with a proximal window <NUM>. The arrangement of the electrodes <NUM> and the windows <NUM> may create an electrical field in the vicinity of windows <NUM>, and thus in the vicinity of the targeted nerve, for example, the left phrenic nerve <NUM>. During nerve stimulation, however, electrical current flows from one or more of the electrodes <NUM> to one or more of the other of the electrodes <NUM>, flowing through the windows <NUM> and through the blood and surrounding tissues. The catheter <NUM> with windows <NUM> therefore acts as an insulating barrier that constrains and focuses the electrical field, rather than allowing the electrical field to expand radially outwards in all directions as the electrical field might with ring electrodes. The focused electrical field allows target nerve stimulation at lower, and thus safer, energy levels and avoids stimulating unwanted nerves or other structures. In some embodiments, the stimulation current may be between <NUM> and <NUM> nC (nano-coulombs) or between <NUM>-<NUM> nC, reducing the risk of overstimulation or unwanted activation of nearby structures such as other nerves, muscles, or the heart.

In a further embodiment, any of the proximal electrodes <NUM> or the distal electrodes <NUM> may be used to measure electrical signals or other data from within the patient's body. In other words, in addition or alternatively to emitting or receiving electrical energy to produce a localized current for nerve stimulation, the electrodes <NUM>, <NUM> may serve as sensors that receive electrical signals or other types of information from the patient.

<FIG> illustrates an exemplary catheter 12A with electrode assemblies 14A, 16A and leads 54A printed directly onto the exterior of catheter 12A. Proximal electrode assemblies 14A, distal electrode assemblies 16A, and leads 54A may be formed by conductive inks (such as silver flakes or carbon flakes suspended in polymer or graphene ink). The conductive inks may be deposited and adhered directly onto the catheter 12A and sealed with an outer polyurethane or other flexible, insulating film or sheath, leaving the electrodes 48A, 50A of the electrode assemblies 14A, 16A at least partially exposed. The insulating film or sheath may be applied to the conductive inks that form electrode assemblies 14A, 16A and leads 54A, or may be applied to the catheter 12A as a whole. In some instances, the insulating film or sheath may be applied by <NUM>-D printing or by other manufacturing processes. For example, at least one tubular sleeve (not shown) may be slid over at least a portion the exterior of catheter 12A. The tubular sleeve may be formed by extrusion, and/or the sleeve may be formed of a thin, thermoplastic material such as, but not limited to, polyamide, polyether block amide, polyurethane, silicone rubber, nylon, polyethylene, fluorinated hydrocarbon polymers, etc. Examples of polymer materials suitable for use in the sleeve are commercially available under the trademarks PEBAX™ and PELLETHANE™. The sleeve may be thermally bonded or mechanically attached to catheter 12A.

The exposed electrodes 48A, 50A may be coated with a conductive material (e.g., titanium nitride) in order to, for example, provide corrosion resistance and reduce the likelihood of silver oxide formation, which may be toxic. The conductive leads 54A electrically connect the proximal electrode assemblies 14A and the distal electrode assemblies 16A through cable <NUM> to control unit <NUM> or other electronics. The leads 54A connected to distal electrode assemblies 16A may travel proximally along catheter 12A beyond the proximal electrode assemblies 14A, for example, on the back side of catheter 12A in <FIG>.

As shown in <FIG>, proximal electrode assemblies 14A and distal electrode assemblies 16A may extend partially circumferentially around a portion of catheter 12A, and, for example, may be partially helical around a portion of the exterior of catheter 12A. Proximal electrode assemblies 14A and distal electrode assemblies 16A may be approximately <NUM> degrees displaced about a circumference of catheter 12A. For example, as shown in <FIG>, proximal electrode assemblies 14A may extend helically <NUM> degrees around the front portion of the catheter 12A, and distal electrode assemblies 16A may extend helically <NUM> degrees around the top (plane of the paper) portion of the catheter 12A, and the proximal electrode assemblies 14A and distal electrode assemblies 16A are approximately <NUM> degrees displaced at right angles to the plane of the paper. As such, the partially helical electrodes 48A, 50A may increase the conductive surface area and broaden the electrical field produced by the electrodes 48A, 50A while still focusing the field on a portion of the circumference of the catheter 12A positioned proximate to, abutting, or facing the target nerve.

The use of printed electrodes and leads may reduce the overall complexity of the design while maximizing the useable catheter lumen space, without drastically changing the catheter profile or flexibility. The use of printed electrodes 14A, 16A and printed leads 54A also allows freedom of electrode position and electrode shape, permitting optimization of field focus and minimum energy for nerve recruitment and capture. Printed leads 54A may be helically disposed between printed electrodes 14A, 16A to allow for greater flexibility in bending the catheter 12A. Additionally, in some embodiments, the profile of the catheter 12A may be reduced because of the space saved by using electrodes printed on the exterior of the catheter 12A, for example, for use with neonate or other young patients. In an additional or alternative embodiment, one or several catheter lumens may be used for fluid delivery, blood sampling, central venous pressure monitoring, or to accommodate tools, sensors, or other objects. In another additional or alternative embodiment, several of the catheter lumens may be eliminated, allowing for larger catheter lumens and/or reducing the cross-sectional size of the catheter 12A.

Referring now to <FIG>, a catheter body or tubular member <NUM> may form the interior of the catheter <NUM>. As shown, tubular member <NUM> may include a guide wire lumen <NUM>, at least two fluid lumens <NUM> and <NUM>, and three lumens or grooves <NUM>, <NUM>, and <NUM>. As discussed, guide wire <NUM> may be threaded though guide wire lumen <NUM>. The fluid lumens <NUM> and <NUM> may be used to deliver and/or remove fluids at a treatment site. Additionally or alternatively, fluid lumens <NUM> and/or <NUM> may be used for other medical devices to treat, diagnose, or sense conditions at the surgical site. Grooves <NUM>, <NUM>, and <NUM> may, for example, be approximately rectangular in a cross-section. Grooves <NUM>, <NUM>, and <NUM> may extend radially to the outer surface of tubular member <NUM> and longitudinally along the tubular member <NUM>. Grooves <NUM>, <NUM>, and <NUM> are exposed along at least a circumference and a portion of a length of tubular member <NUM> and may be spaced approximately <NUM> degrees from each other around the circumference of the tubular member <NUM>. Grooves <NUM>, <NUM>, and <NUM> in tubular member <NUM> may accommodate electrical leads to connect control unit <NUM> to proximal electrodes <NUM> (shown in <FIG> and <FIG>) and distal electrodes <NUM>. As shown, electrodes <NUM>, <NUM> may extend longitudinally over a portion of tubular member <NUM> and may approximate the width of the grooves <NUM>, <NUM>, and <NUM> and/or the width of windows <NUM>, <NUM>.

In one aspect, the leads may be formed by ribbon cables <NUM>', <NUM>", and <NUM>'''. As shown in <FIG>, a connector feed <NUM> may be positioned within groove <NUM> and recessed within the outer perimeter of tubular member <NUM>. Connector feed <NUM> may send and transmit signals to an application specific integrated circuit ("ASIC") <NUM>. Connector feed <NUM> may also be formed by a ribbon cable. ASIC <NUM> may then be connected to three ribbon cables <NUM>', <NUM>", and <NUM>‴ that branch out and connect to the proximal electrode assemblies <NUM> and distal electrode assemblies <NUM>. Ribbon cables <NUM>', <NUM>", and <NUM>'" may be accommodated in grooves <NUM>, <NUM>, and <NUM> in tubular member <NUM>. Partially circumferential grooves <NUM> extend around at least part of a circumference of the tubular member <NUM> to allow the ribbon cables <NUM>', <NUM>", and <NUM>'" to branch out without extending away from or interfering with the tubular member <NUM> fitting within an outer covering of catheter <NUM>.

Ribbon cables <NUM>', <NUM>", and <NUM>‴ are flexible and include multiple insulated leads <NUM> (some of which are labeled in <FIG>) connected along their lengths to form a single, flexible planar structure. The planar structure is flexible to allow the formation of other shapes, such as bends and/or corrugations. The leads <NUM> within ribbon cables <NUM>', <NUM>", and <NUM>‴ may include a wire or a rod-like conductive member. Leads <NUM> are surrounded by a layer of non-conducting material <NUM>, such as insulation (<FIG>). Ribbon cables <NUM>', <NUM>", and <NUM>‴ may be similar to printed circuits formed using thin flexible polyimide substrates with copper plated conductors. Typical dimensions include an insulation base layer about <NUM> (<NUM> in) thick, a copper conductor about <NUM> (<NUM> in) thick by <NUM> (<NUM> in) wide, an insulation cover layer about <NUM> (<NUM> in) thick, and a lateral spacing between conductors of about <NUM> (<NUM> in). The ribbon cables <NUM>', <NUM>", and <NUM>‴ may be secured within the grooves <NUM>, <NUM>, and <NUM> by application of a heat shrink polyolefin tube around the outside of tubular member <NUM>. Windows may be formed by ablating the heat shrink tube locally over the electrodes <NUM>, <NUM> using a CO<NUM> laser. As such, any of the leads <NUM> may be uninsulated at a point along the length of catheter <NUM> and coupled to an electrode <NUM>, <NUM>, such as, for example, a flexible foil electrode or an electrode formed according to any of the embodiments described herein and exposed through a window <NUM>, <NUM> of catheter <NUM>.

In one example, connector feed <NUM> may include approximately <NUM> electrical leads in a ribbon cable, and ribbon cables <NUM>', <NUM>", and <NUM>'" may include enough electrical leads <NUM> to send electrical signals to each electrode <NUM>, <NUM> of the proximal electrode assemblies <NUM> and distal electrode assemblies <NUM>. For instance, connector feed <NUM> may include an electrical lead for each of power, ground, data stream, anode signal, cathode signal, and leads to send and receive signals from various elements in catheter <NUM>. Ribbon cables <NUM> connect to each electrode <NUM>, <NUM> of the electrode assemblies <NUM>, <NUM> in order to stimulate the targeted nerves.

ASIC <NUM> may serve to direct the signals received from connector feed <NUM>. For example, based on the received signals, ASIC <NUM> may direct electrical signals to one or a plurality of the electrodes <NUM>, <NUM> of the proximal electrode assemblies <NUM> and the distal electrode assemblies <NUM>. As such, there may be only one connection and/or connector at the proximal end of catheter <NUM> to transmit electrical or other signals distally from, for example, control unit <NUM>, to the proximal and distal electrode assemblies <NUM> and <NUM>, providing further space within tubular member <NUM> for the fluid lumens <NUM> and <NUM>, additional medical instruments, and/or allowing the tubular member <NUM> and the remainder of the catheter <NUM> to be smaller. ASIC <NUM> allows for a reduction in conductors in the connector feed <NUM>, and thus reduces the number of couplings between connector feed <NUM> and ASIC <NUM>, improving reliability and reducing cost. Moreover, ASIC <NUM> permits the use of a connector with <NUM> or <NUM> pins, rather than a connector with <NUM> pins, further improving reliability and reducing the risk of signal interference or misalignment.

<FIG> illustrates a schematic view of the connector feed <NUM>, ASIC <NUM>, ribbons cables <NUM>', <NUM>", <NUM>‴, and the electrode assemblies <NUM>, <NUM>. Ribbon cables <NUM>', <NUM>", <NUM>‴ may be three separate ribbon cables, or may be one ribbon cable that branches out into three ribbon cables. As discussed, connector feed <NUM> may include <NUM> conductor leads <NUM> connected to ASIC <NUM>. ASIC <NUM> connects to ribbon cables <NUM>', <NUM>", <NUM>'" to selectively deliver signals to one or a plurality of the proximal electrodes <NUM> or the distal electrodes <NUM>. Proximal electrodes <NUM> and distal electrodes <NUM> may be mounted or otherwise physically and electrically connected to the corresponding ribbon cable <NUM>', <NUM>", <NUM>‴. In one example, ribbon cables <NUM>', <NUM>", <NUM>‴ may include one lead <NUM> per electrode <NUM>, <NUM>, with the particular lead <NUM> terminating in an uninsulated portion where the lead <NUM> is coupled to the electrode <NUM>, <NUM> by mechanical rivet, solder, crimping, or another technique.

As shown in <FIG> and <FIG>, one ribbon cable <NUM>' may include one proximal electrode assembly <NUM> with six proximal electrodes <NUM>. One ribbon cable <NUM>" may include one proximal electrode assembly <NUM> with six proximal electrodes <NUM> and one distal electrode assembly <NUM> with three distal electrodes <NUM>. One ribbon cable <NUM>'" may include one distal electrode assembly <NUM> with three distal electrodes <NUM>. ASIC <NUM> may decode the signals from connector feed <NUM> and determine if a particular electrode <NUM>, <NUM> is to be an anode or a cathode, so each of the ribbon cables <NUM>', <NUM>", <NUM>‴ may only require one lead for each of the electrodes <NUM>, <NUM> connected to that ribbon cable <NUM>', <NUM>", <NUM>‴. In this situation, ribbon cable <NUM>' may include six leads <NUM> to connect to the six proximal electrodes <NUM>. Ribbon cable <NUM>" may include nine leads <NUM> to connect to the six proximal electrodes <NUM> and three distal electrodes <NUM>. Ribbon cable <NUM>‴ may include as few as three leads <NUM>. The proximal electrodes <NUM> of the two proximal electrode assemblies <NUM> may be aligned (positioned at the same axial position and different circumferential positions), and the distal electrodes <NUM> of the two distal electrode assemblies <NUM> may be displaced (positioned at different axial positions and different circumferential positions). The electrodes <NUM>, <NUM> may also take different orientations and arrangements in order to locate and/or stimulate the target nerves.

<FIG> illustrates an axial cross-sectional view of a proximal portion of the catheter <NUM>, including tubular member <NUM> and an outer layer or sheath <NUM>, at a position of proximal electrode assemblies <NUM>. As shown, guide wire lumen <NUM>, fluid lumens <NUM> and <NUM>, and grooves <NUM>, <NUM>, and <NUM> longitudinally pass through tubular member <NUM>. Ribbon cables <NUM>', <NUM>", and <NUM>‴ with leads <NUM> are positioned within grooves <NUM>, <NUM>, and <NUM>. Proximal electrodes <NUM> are mounted over ribbon cables <NUM>' and <NUM>" and are exposed through proximal windows <NUM>. Although not shown, distal electrodes <NUM> are mounted and/or connected to ribbon cables <NUM>" and <NUM>'" and exposed through distal windows <NUM> in a similar manner to the proximal electrodes <NUM>.

In another aspect of this disclosure, the tubular member <NUM> may include printed ink conductors and electrodes similar to that shown in <FIG>. In this example, the printed ink conductors may extend distally from ASIC <NUM> and branch out in a similar manner as discussed above, but with the printed ink conductors extending along the circumferential surface of the tubular member <NUM>. The printed ink conductors may connect to printed electrodes, and signals may be selectively transmitted via the ASIC <NUM> to the electrodes through the printed ink conductors.

Tubular member <NUM> may be extruded polyurethane (or any other suitable biocompatible material). Sheath <NUM> fitting over tubular member <NUM> may be made of any biocompatible plastic or other material. In one aspect, sheath <NUM> is a <NUM> thick polyolefin shrink tube that may be positioned around tubular member <NUM> and shrunk down using a heat gun or other heating source. Windows <NUM> may be formed by ablating the heat shrink tube locally over the electrodes <NUM>, <NUM> using a CO<NUM> laser. Alternatively, sheath <NUM> may be a <NUM>-D printed insulation layer with windows <NUM> over electrodes <NUM>, <NUM> formed by open portions during the <NUM>-D printing.

<FIG> illustrates a longitudinal cross-sectional view of a portion of one groove <NUM> in the tubular member <NUM>, and <FIG> illustrates an exploded view of a portion of a ribbon cable <NUM>" that may fit within groove <NUM>. The configuration in <FIG> shows an arrangement where electrode <NUM> is coupled at one end of the electrode to the appropriate lead <NUM> of ribbon cable <NUM>" and corrugations <NUM> in ribbon cable <NUM>" pass beneath electrode <NUM>. Such an arrangement may be used if the distance between electrodes <NUM>, <NUM> is short, and using as many corrugations as possible provides maximum longitudinal and rotational flexibility for the ribbon cables <NUM>', <NUM>", and <NUM>'" in the catheter. Alternatively or additionally, as in <FIG>, corrugations <NUM> in ribbon cables <NUM>', <NUM>", and <NUM>'" may be located between electrodes only, and not under the electrodes.

As shown in <FIG>, ribbon cable <NUM>" may be coupled to proximal electrode <NUM> via a connection <NUM>. Connection <NUM> electrically and physically connects electrode <NUM> to the appropriate lead <NUM> of ribbon cable <NUM>" that corresponds to electrode <NUM>. Connection <NUM> may be, for example, a wire connection with solder or a rivet. Electrode <NUM> may longitudinally overlap with ribbon cable <NUM>", and may extend longitudinally and be positioned radially underneath a portion of tubular member <NUM>. A portion of electrode <NUM> may be exposed through window <NUM> and may be partially covered by a non-insulating and/or conductive cover <NUM>.

Proximal electrode <NUM> may be exposed via proximal window <NUM> in sheath <NUM>. A proximal electrode <NUM>, along with the other electrodes <NUM>, <NUM>, may be a sheet Platinum-Iridium (Ptlr) electrode with a thickness of approximately <NUM>-<NUM> (<NUM>-<NUM> in). Ribbon cable <NUM>" may be coupled to the other proximal electrodes <NUM> and the distal electrodes <NUM> in the same manner as illustrated in <FIG>. Electrodes <NUM>, <NUM> may be various other known electrode assemblies, for example, ring electrodes fixed to the exterior of catheter <NUM>. Electrodes <NUM>, <NUM> may also be formed of other conductive materials, including platinum, gold, stainless steel, titanium nitride, MP35N, palladium, or another appropriate material. Electrodes <NUM>, <NUM> may also be coupled to ribbon cables <NUM>', <NUM>", and <NUM>‴ with conductive adhesive, heat fusion, crimping, riveting, microwelding, or another appropriate method. Electrodes <NUM>, <NUM> may also include an insulating coating over a portion of the electrodes <NUM>, <NUM> that may facilitate directional targeting of one or more nerves.

Each ribbon cable <NUM>', <NUM>", and <NUM>‴ may also include corrugations <NUM> within at least one or more portions of grooves <NUM>, <NUM>, and <NUM>. Corrugations <NUM> may provide greater longitudinal and lateral flexibility and bendability of the catheter <NUM> and the internal components. Corrugations <NUM> may pass underneath an electrode <NUM>, as shown in <FIG>. Alternatively or additionally, corrugations <NUM> may be positioned along ribbon cables <NUM>', <NUM>", and <NUM>‴ between longitudinally adjacent electrodes <NUM>, <NUM>, as shown in <FIG>. In this aspect, a filler block <NUM> may support electrode <NUM>, <NUM> and ribbon cable <NUM>". A filler strip <NUM> may include contours <NUM> that mirror the corrugations <NUM>. Contours <NUM> may extend radially inwardly to fit within corrugations <NUM>. Filler strip <NUM> may be positioned on a radially outward side of ribbon cable <NUM>" to support the corrugations <NUM> of ribbon cable <NUM>" between electrodes <NUM>, <NUM>. Corrugations <NUM> of ribbon cable <NUM>" may be unsupported or open on the radially inward side of corrugations opposite to filler strip <NUM> and contours <NUM>, which may increase the longitudinal or lateral flexibility. Filler blocks <NUM> and filler strips <NUM> may be elastomeric and may be sized to fit within grooves <NUM>, <NUM>, and <NUM> of tubular member <NUM>.

<FIG> illustrate an alternative embodiment of the disclosure, including tubular member <NUM> and helical ribbon cable <NUM> that may be radially surrounded by an outer layer, sleeve, or sheath <NUM> to form a catheter <NUM> to stimulate target nerves as discussed above, according to another aspect of this disclosure.

<FIG> illustrates a portion of tubular member <NUM>. Tubular member <NUM> is sized to fit within sheath <NUM> in a similar manner to tubular member <NUM> (<FIG>). Tubular member <NUM> includes a series of lumens <NUM>, which may include a guide wire lumen and fluid lumens that may function as discussed above. Tubular member <NUM> includes a radial extension <NUM>. Radial extension <NUM> extends radially outward from tubular member <NUM>. Radial extension <NUM> may be integrally formed of the same material as tubular member <NUM>, or may be a separate element attached to or positioned around tubular member <NUM>. Radial extension <NUM> may helically extend along an outer surface of tubular member <NUM> and include a helical pitch <NUM>. Electrode locations <NUM> may be located such that there are at least portions of radial extension <NUM> between electrode locations <NUM>, as shown in <FIG>, to form an electrode pitch <NUM>. One or both of tubular member <NUM> and radial extension <NUM> may be formed by, for example, extrusion, molding, or <NUM>-D printing using XYZ and rotary motions to deposit a flexible polymer around a mandrel, with some or all of the polymer being sacrificial.

<FIG> illustrates a portion of helical ribbon cable <NUM> with electrodes <NUM> mounted on helical ribbon cable <NUM>. <FIG> shows a top view of cable <NUM> in a straight, flat configuration prior to its placement around tubular member <NUM>. Helical ribbon cable <NUM> may be formed and may function similarly to ribbon cables <NUM>', <NUM>", and <NUM>‴ with leads <NUM> surrounded by non-conducting material <NUM> as discussed above. Additionally, electrodes <NUM> may be coupled to ribbon cable <NUM> as with electrodes <NUM>, <NUM> and ribbon cables <NUM>', <NUM>", and <NUM>‴. Helical ribbon cable <NUM> may include an upper conductor <NUM> having multiple leads that communicate with the upper electrodes <NUM>, and a lower conductor <NUM> also having multiple leads communicating with the lower electrodes <NUM>. Conductors <NUM> and <NUM> are surrounded by and separated by insulating layers <NUM>.

Electrodes <NUM> are mounted on helical ribbon cable <NUM> at an angle to the axis of the helical ribbon cable <NUM> such that the electrodes lie at the correct axially disposed angle when the helical ribbon cable <NUM> is wrapped around the tubular member <NUM> in the helical recess defined by radial extensions <NUM>. After wrapping the helical ribbon cable <NUM> around the tubular member, the electrodes <NUM> adopt the alignment shown by locations <NUM> in <FIG>. In one example, if the electrodes <NUM> are to be oriented with the electrodes' shorter dimension disposed circumferentially around the tubular member <NUM> after helical ribbon cable <NUM> is helically wrapped, then electrodes <NUM> may be mounted on helical ribbon cable <NUM> at approximately a <NUM> degree angle relative to a longitudinal axis of the helical ribbon cable <NUM>. The length of helical ribbon cable <NUM> between paired electrodes <NUM> corresponds to an electrode pitch <NUM> between paired electrode locations <NUM>. Therefore, when the helical ribbon cable <NUM> is wrapped around tubular member <NUM> between radial extensions <NUM>, paired electrodes <NUM> align with electrode locations <NUM>. For example, if the electrode pitch <NUM> is about <NUM>, and the tubular member <NUM> has an outside diameter of about <NUM>, then the distance between sets of paired electrodes on helical ribbon cable <NUM> is approximately <NUM>.

As shown in <FIG>, catheter <NUM> may include tubular member <NUM> and helical ribbon cable <NUM> positioned within sheath <NUM>. Electrodes <NUM> and helical ribbon cable <NUM> may function as discussed above, without interfering with lumens <NUM> and other radially internal elements of tubular member <NUM>. Moreover, electrodes <NUM> may be electrically and physically coupled to helical ribbon cable <NUM> via connection <NUM>. Connection <NUM> may be, for example, a wire connection, a solder connection, a rivet, or another mechanical and electrical connection to mechanically and electrically connect electrode <NUM> to helical ribbon cable <NUM>. Electrodes <NUM> may then be exposed via an electrode window <NUM>. Sheath <NUM> may also radially surround tubular member <NUM>, and sheath <NUM> may comprise one or more insulating layers of flexible polyimide, shrink tubing, and/or a flexible filler.

<FIG> illustrates an aspect of the present disclosure that may be incorporated in any of the foregoing aspects. As shown in <FIG>, each electrode <NUM> may be coupled to a small ASIC <NUM>. For example, helical ribbon cable <NUM> may be coupled to a tubular member 100A as part of a catheter 112A. Tubular member 100A may include guide wire lumen <NUM>, two fluid lumens <NUM> and <NUM>, and grooves <NUM>, <NUM>, and <NUM>, similar to as shown in <FIG>. Small ASICs <NUM> may be positioned within grooves <NUM>, <NUM>, and <NUM> radially between electrodes <NUM>, <NUM> and guidewire lumen <NUM>. The small ASICs <NUM> allow for a reduction of conductive leads <NUM>. For example, unless an ASIC <NUM> is located locally for each electrode <NUM>, <NUM>, there must be a separate lead <NUM> for each electrode <NUM>, <NUM>. With an ASIC <NUM> specific to each electrode, the ASIC <NUM> may decode a signal from a control unit and determine whether the signal applies to that particular electrode <NUM>, <NUM>. Therefore, helical ribbon cable <NUM>, or other ribbon cable in other aspects of this disclosure, would be connected through the electrode-specific ASICs <NUM> to all electrodes <NUM>, <NUM>, and the helical ribbon cable <NUM> would only need five conductive leads <NUM> (an anode reference, a cathode reference, a power, a ground, and a data line) for any number of electrodes <NUM>, <NUM>. It is further noted that locally located ASICs <NUM> require a groove or recess in the tubular member 100A, but may also be incorporated in other tubular members or catheters of this disclosure. For instance, grooves or recesses may be extruded in tubular member 100A, and tubular member 100A may be extruded, <NUM>-D printed, or otherwise formed to include helical lumens such that the grooves or recesses do not interfere with the lumens. Grooves or recesses may also be helical, and the helical grooves or recesses, along with helical lumens, may be formed by extruding the tubular member as with longitudinal grooves, and lumens, and then heat setting the tubular member in a twisted state. Each electrode <NUM> may be exposed through a window (similar to as shown in <FIG>), or may be partially covered by a non-insulating and/or conductive element <NUM>, as shown in <FIG>.

Once positioned within a patient, the catheter 112A of <FIG>, with helical ribbon <NUM> and small ASICs <NUM>, may be used to stimulate the target nerves as discussed above. In particular, the conductive leads of the helical ribbon cable <NUM> may be reduced because each lead of the same helical ribbon cable <NUM> may connect to each small ASIC <NUM>. Based on the signals through the leads of the helical ribbon cable <NUM>, each small ASIC <NUM> controls whether the electrical signals through leads are emitted through the particular electrodes <NUM>. Similar to the example shown in <FIG>, the catheter 112A of <FIG> may only include one connection at the proximal end of catheter 112A to transmit electrical or other signals distally to the proximal and distal electrode assemblies <NUM> and <NUM>, providing further space within tubular member 100A for the fluid lumens <NUM> and <NUM>, additional medical instruments, and/or allowing the tubular member 100A and catheter 112A to be smaller.

<FIG> illustrates an alternative medical system <NUM> with similar elements to the medical system <NUM> of <FIG> shown by <NUM> added to the reference numbers. Medical system <NUM> includes a wireless connection from control unit <NUM> to catheter <NUM>. Catheter <NUM> may be inserted and positioned as discussed with respect to <FIG>. Catheter <NUM> may include proximal and distal electrode assemblies <NUM>, <NUM> that are exposed through proximal and distal windows as discussed above.

Instead of proximal connector <NUM>, catheter <NUM> may include a manifold or hub <NUM> at a proximal end or coupled to the proximal end of catheter <NUM>. Hub <NUM> may be positioned external to the patient when catheter <NUM> is inserted. Hub <NUM> may include a plurality of lumens that may connect to the guide wire and fluid lumens within catheter <NUM>. In one aspect, hub <NUM> may be connected to a fluid port <NUM> and a wireless unit <NUM>. Fluid port <NUM> may include one lumen connected through hub <NUM> to a lumen in catheter <NUM>, or fluid port <NUM> may include a plurality of lumens connected through hub <NUM> to lumens within catheter <NUM>, including a guide wire port. Wireless unit <NUM> may include a battery and a receiver/transmitter. The receiver/transmitter of wireless unit <NUM> may be in wireless communication with control unit <NUM>, via, for example, a Bluetooth connection. As such, control unit <NUM> may send signals to and receive signals from wireless unit <NUM>. Wireless unit <NUM> may then be coupled to one or more leads or ribbon cables to transmit electrical signals distally to the proximal and distal electrode assemblies <NUM>, <NUM>, and the signals may be distributed via one or more ASICs within catheter <NUM> to stimulate a target nerve.

Wireless unit <NUM>, or catheter <NUM> itself, may also include a wireless information unit (not shown), for example, an RFID tag or wireless chip, or other unique coded information related to the catheter <NUM> including, for example, the catheter serial number and construction change level. For instance, as improvements to the catheter are made over time, each improvement is recorded as a change level. This change level may, for example, include an electrode material change or an electrode surface finish. These changes may permit the use of a more effective stimulation pulse stream. The control unit <NUM> may evaluate the change level code and determine whether a new stimulation program installed on the control unit <NUM> is applicable to that catheter <NUM>, as the software of control unit <NUM> may also be updated periodically. The change level code may avoid the creation of "generic" pirated clones by detecting false codes and preventing the system from operating if a false code is detected. As such, this would also reduce the risks to the patient, medical professional, and manufacturer by eliminating the risk of inferior devices being improperly used without the proper clinical testing and approval. The wireless information unit may further record usage data for catheter <NUM>, including, for example, time of day of use, duration of use, number of times used, and other information related to communications from control unit <NUM>. Hub <NUM> with wireless unit <NUM> does not require a wired connection between the control unit <NUM> and the catheter <NUM>, reducing the assembly time for a medical professional and reducing the risk of signal interference, misalignment, cable snagging, and other human errors.

Alternatively, though not shown, wireless unit <NUM> may receive all data wirelessly from control unit <NUM>, but the low voltage power necessary for the receiver in wireless unit <NUM> may be delivered by a low-cost three conductor cable from the control unit <NUM>. This arrangement allows the system to operate for long periods of time without the risk of running low on battery power. Although this arrangement requires a cable for power, the arrangement nevertheless results in a minimal number of pins in the connections to the control unit, thereby enhancing reliability and reducing the risk of misalignment.

<FIG> and <FIG> illustrate an alternative catheter <NUM> with similar elements to the catheter <NUM> of <FIG> shown by <NUM> added to the reference numbers. Aspects shown in <FIG> and <FIG> may be incorporated in any of the foregoing catheter examples in order to ensure that the catheter <NUM> is aligned properly. As shown in <FIG>, catheter <NUM> may be radiopaque and may be viewed via one or more imaging systems, for example, via fluoroscopy, X-ray, or other imaging methods. Catheter <NUM> may be made to be radiopaque by using a polymer that is approximately <NUM>% BaSO<NUM>, or by printing radiopaque ink on the exterior of the catheter. Radiopaque catheter <NUM> may include two proximal electrode assemblies <NUM>, each with six proximal electrodes <NUM> exposed via proximal windows <NUM>, and two distal electrode assemblies <NUM>, each with three distal electrodes <NUM> exposed via distal windows <NUM>. Electrodes <NUM>, <NUM> may also be radiopaque, for example, containing <NUM>% Platinum-Iridium (Ptlr), and may appear to be darker than the radiopaque catheter <NUM>.

<FIG> shows an anterior view of radiopaque catheter <NUM> properly aligned such that proximal electrodes <NUM> face substantially posteriorly (to the patient's back) to stimulate the left phrenic nerve <NUM>, and distal electrodes <NUM> face substantially laterally (to the patient's right) to stimulate the right phrenic nerve <NUM>. When viewed anteriorly, the proximal electrodes <NUM> may appear in two aligned rows of six electrodes in the center of the catheter <NUM>. The distal electrodes <NUM> may appear in a single row of six electrodes positioned toward the lateral (patient's right) edge of the catheter <NUM>. Moreover, the proximal electrodes <NUM> and three alternating distal electrodes <NUM> may appear to be darker than the catheter shaft <NUM>, even though these electrodes are posterior facing. Three alternating distal electrodes <NUM> may appear to be even darker than the other electrodes as these electrodes are anterior facing. If the catheter <NUM> and electrodes <NUM>, <NUM> appear differently than shown and described, the catheter <NUM> and electrodes <NUM>, <NUM> are likely improperly positioned. As such, a medical professional may use this visualization to ensure that the catheter <NUM> and electrodes <NUM>, <NUM> are positioned properly when stimulating or preparing to stimulate target nerves.

<FIG> illustrates an additional example of catheter <NUM> that is radiopaque and may aid in ensuring the catheter <NUM> and electrodes <NUM>, <NUM> are properly positioned. As with <FIG>, when viewed anteriorly via an imaging system, a properly positioned catheter <NUM> may include two rows of six proximal electrodes <NUM> in the center of the catheter <NUM>, and one row of six distal electrodes <NUM> toward the lateral (patient's right) edge of the catheter <NUM>. The proximal electrodes <NUM> and three alternating distal electrodes <NUM> may appear darker than the catheter <NUM>, and three alternating distal electrodes <NUM> may appear even darker than the other electrodes.

As shown in <FIG>, catheter <NUM> may further include one or more radiopaque markers <NUM>. For example, catheter <NUM> may include a one radiopaque marker <NUM> at a distal end of the catheter <NUM>, and one radiopaque marker <NUM> at a proximal end of the catheter <NUM>. Radiopaque markers <NUM> may be formed by printing or otherwise applying radiopaque ink to the catheter <NUM>. When viewed with an imaging system, the orientation and/or appearance of the radiopaque markers <NUM> may allow a medical professional to determine whether the catheter <NUM> is properly positioned and/or oriented. For example, the distal radiopaque marker <NUM> may be a check mark, and the proximal radiopaque marker <NUM> may be a smiley face, as shown in <FIG>. When viewed anteriorly, if the checkmark is longer on the right side, and the smiley face is right-side up, then the catheter <NUM> is properly oriented. Otherwise, orientation is not proper, and the user may adjust the position of catheter <NUM>.

Catheter <NUM> may include a further radiopaque orientation marker, for example, orientation stripe <NUM>. Orientation stripe <NUM> may extend longitudinally along at least a portion of the length of the catheter <NUM> such that when viewed anteriorly with an imaging system, the orientation stripe <NUM> passes through the middle of the catheter <NUM>. Orientation stripe <NUM> may bisect or align with a midpoint of the radiopaque markers <NUM>. Orientation stripe <NUM> may be positioned on catheter <NUM> such that, when the catheter <NUM> and electrodes <NUM>, <NUM> are properly positioned and viewed anteriorly using an imaging system, orientation stripe <NUM> passes evenly between the two rows of proximal electrodes <NUM> and passes to the medial (patient's left) side of the one row of distal electrodes <NUM>. Orientation stripe <NUM> may be formed during the formation of the catheter <NUM>, for example, during an extrusion. Orientation stripe <NUM> may include a different color or pattern, may be laser marked, may be printed with radiopaque ink, may be a radiopaque wire introduced into a dedicated lumen of the catheter body, or may be formed by any other appropriate methods. If the catheter <NUM> is not properly positioned, the catheter <NUM> may be adjusted until the electrodes <NUM>, <NUM>, radiopaque markers <NUM>, and orientation stripe <NUM> appear when viewed anteriorly as illustrated in <FIG>.

Orientation stripe <NUM> may be also be used to control the orientation of the catheter <NUM> while inserting catheter <NUM> into a patient without taking an x-ray or using another visualization technique. For example, orientation stripe <NUM> may run longitudinally from the distal end to the proximal end of catheter <NUM>. Therefore, as long as the catheter <NUM> is not undergoing torsion, a medical professional is able to determine the orientation of the distal end, which is inserted into the patient and thus not visible without imaging technology, by observing the location of the orientation stripe <NUM> on the proximal end that extends proximally from the patient.

Radiopaque catheter <NUM> may also include an orientation hub <NUM>. For example, the shape and size of orientation hub <NUM> may be such that orientation hub may be sutured or otherwise attached in only one orientation. Orientation hub <NUM> may have an apex <NUM> that circumferentially aligns with orientation stripe <NUM> on catheter <NUM>, and which is opposite to a flat bottom that may rest on a patient's chest or another surface. The flat bottom may also include two attachment members or suture tabs <NUM> extending from the bottom such that the bottom may be coupled to other elements in the proper orientation. Additionally or alternatively, orientation hub <NUM> may include a wireless unit as discussed above with respect to <FIG>.

Catheter <NUM> may include all or a portion of the aforementioned positioning markers. Additionally, a medical professional may use different positioning markers to ensure the catheter <NUM> is positioned properly as different markers may exhibit greater visibility depending on the patient, the imaging system, and other variables. Catheter <NUM> and the various positioning and orientation markers may be modified and/or customized depending on the patient. For example, fewer electrodes <NUM>, <NUM> may be used with a smaller patient, for example, a neonate. Alternatively, a patient with abnormal nerve locations may require a different catheter orientation and/or arrangement.

As noted earlier, any of the components and features of any of the embodiments disclosed herein may be combined and used in any suitable combinations with any of the other components and features disclosed herein. However, for the sake of example, some ways in which the described example embodiments may be varied include:.

As mentioned above, the use of the various catheter embodiments allows for an increase in the number of available lumens within the catheter. The size of the catheter may also be reduced, for example, for use in neonatal patients or patients who require a smaller catheter. Ribbon cables increase the longitudinal flexibility of the catheter and the electrode connections during the manipulation and use of the catheter. Using ASICs and/or wireless connections reduces the number of cables and connections the medical professional must properly connect and avoid during various procedures, while still properly and accurately stimulating various internal nerves. Additionally, radiopaque catheters, radiopaque electrodes, radiopaque markers, and orientation markers may aid a medical professional in locating the position of the catheter and orienting the catheter in order to most effectively stimulate the patient's nerves.

Claim 1:
A catheter (<NUM>, <NUM>, <NUM>), comprising:
an outer layer (<NUM>) defining a plurality of apertures (<NUM>, <NUM>) therethrough;
a body (<NUM>) defining at least one longitudinal lumen therein, wherein at least a portion of the body (<NUM>) is within the outer layer (<NUM>), and the apertures (<NUM>, <NUM>) are radially outward of the lumen;
a plurality of electrodes (<NUM>, <NUM>) positioned in or on the catheter (<NUM>, <NUM>, <NUM>), each electrode (<NUM>, <NUM>) being electrically exposed through an aperture (<NUM>, <NUM>) of the plurality of apertures (<NUM>, <NUM>);
a ribbon cable (<NUM>', <NUM>", <NUM>‴) including a plurality of leads (<NUM>), the plurality of leads (<NUM>) being electrically connected to the plurality of electrodes (<NUM>, <NUM>);wherein the plurality of leads (<NUM>) are at least partially surrounded by a non conducting material; and
wherein the ribbon cable (<NUM>', <NUM>", <NUM>‴) is electrically connected to at least one electrode (<NUM>, <NUM>) via a connection,
wherein
the plurality of electrodes (<NUM>, <NUM>) includes a distal set of electrodes (<NUM>, <NUM>) and a proximal set of electrodes (<NUM>, <NUM>); and characterized in that
the catheter (<NUM>, <NUM>, <NUM>) further comprises:
a first radiopaque structure (<NUM>) located distal to at least one electrode of the proximal set of electrodes; and
a second radiopaque structure (<NUM>) located proximal to at least one electrode of the distal set of electrodes.