Irrigation fluid monitor and alarm

Abstract

To provide an irrigation fluid monitor and alarm.SOLUTION: An apparatus includes a fluid bag support coupling, a signal generating assembly, and a signal output driver circuit. The fluid bag support coupling is configured to support a fluid source. The signal generating assembly is configured to generate a signal in response to an amount of fluid within the fluid source. The signal output driver circuit is in electrical communication with the signal generating assembly. The signal output driver circuit is configured to transmit the signal from the signal generating assembly to a working element configured to perform a task. The signal is configured to inhibit the working element from performing the task when the amount of fluid within the fluid source reaches a predetermined threshold amount.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] (Priority) This application claims priority to U.S. Provisional Patent Application No. 62 / 866,106, filed June 25, 2019, entitled "Irrigation Fluid Monitor and Alarm," the disclosure of which is incorporated herein by reference in its entirety. [Background technology]

[0002] Cardiac arrhythmias, such as atrial fibrillation, occur when regions of cardiac tissue abnormally transmit electrical signals. Procedures for treating arrhythmias include surgically disrupting the transmission pathways of such signals. By selectively ablating cardiac tissue through the application of energy (e.g., radiofrequency (RF) energy), it may be possible to stop or modify the propagation of unwanted electrical signals from one part of the heart to another. The ablation process can provide a barrier to the unwanted electrical pathways by creating electrically insulating lesions or scar tissue that effectively block the transmission of abnormal electrical signals across the tissue.

[0003] In some procedures, ablation can be performed within the cardiovascular system using a catheter equipped with one or more RF electrodes. A catheter can be inserted into a major vein or artery (e.g., the femoral artery) and then advanced to place electrodes within the heart or cardiovascular structures adjacent to the heart (e.g., the pulmonary veins). One or more electrodes can be placed in contact with cardiac tissue or other vascular tissue and then activated with RF energy, thereby ablating the contacted tissue. In some cases, the electrodes may be bipolar. In some other cases, a monopolar electrode may be used in conjunction with a grounding pad or other reference electrode in contact with the patient. Irrigation can be used to draw heat away from the ablation components of the ablation catheter and prevent the formation of thrombus near the ablation site.

[0004] Examples of ablation catheters are described in U.S. Patent Application Publication No. 2013 / 0030426, entitled "Integrated Ablation System using Catheter with Multiple Irrigation Lumens," published January 31, 2013 (the entire disclosure of which is incorporated herein by reference); U.S. Patent Application Publication No. 2017 / 0312022, entitled "Irrigated Balloon Catheter with Flexible Circuit Electrode Assembly," published November 2, 2017 (the entire disclosure of which is incorporated herein by reference); U.S. Patent Application Publication No. 2018 / 0071017, entitled "Ablation Catheter with a Flexible Printed Circuit Board," published March 15, 2018 (the entire disclosure of which is incorporated herein by reference); and U.S. Patent Application Publication No. 2018 / 0056038, entitled "Catheter with Bipole Electrode Spacer and Related No. 10,130,422, entitled "Catheter with Soft Distal Tip for Mapping and Ablating Tubular Region," issued on November 20, 2018 (the entire disclosure of which is incorporated herein by reference); U.S. Pat. No. 8,956,353, entitled "Electrode Irrigation Using Micro-Jets," issued on February 17, 2015 (the entire disclosure of which is incorporated herein by reference); and U.S. Pat. No. 9,801,585, entitled "Electrocardiogram Noise Reduction," issued on October 31, 2017 (the entire disclosure of which is incorporated herein by reference).

[0005] Some catheter ablation procedures may be performed after using electrophysiology (EP) mapping to identify tissue regions to be targeted for ablation. Such EP mapping may involve the use of sensing electrodes on a catheter (e.g., the same catheter used to perform the ablation or a dedicated mapping catheter). Such sensing electrodes can monitor electrical signals emanating from conductive endocardial tissue to pinpoint the location of abnormal conductive tissue sites involved in arrhythmias. An example of an EP mapping system is described in U.S. Pat. No. 5,738,096, entitled "Cardiac Electromechanics," issued April 14, 1998, the entire disclosure of which is incorporated herein by reference. Examples of EP mapping catheters are described in U.S. Pat. No. 9,907,480, entitled "Catheter Spine Assembly with Closely-Spaced Bipole Microelectrodes," issued March 6, 2018 (the entire disclosure of which is incorporated herein by reference); U.S. Pat. No. 10,130,422, entitled "Catheter with Soft Distal Tip for Mapping and Ablating Tubular Region," issued November 20, 2018 (the entire disclosure of which is incorporated herein by reference); and U.S. Patent Application Publication No. 2018 / 0056038, entitled "Catheter with Bipole Electrode Spacer and Related Methods," published March 1, 2018 (the entire disclosure of which is incorporated herein by reference).

[0006] When using an ablation catheter, it may be desirable to ensure that one or more electrodes of the ablation catheter make sufficient contact with the target tissue. For example, it may be desirable to ensure that one or more electrodes make contact with the target tissue with sufficient force to effectively apply RF ablation energy to the tissue, while avoiding applying an amount of force that would tend to unnecessarily damage the tissue. To this end, it may be desirable to include one or more force or pressure sensors to detect sufficient contact between one or more electrodes of the ablation catheter and the target tissue.

[0007] In addition to using force sensing or EP mapping, some catheter ablation procedures may be performed using an image-guided surgery (IGS) system. IGS systems can allow a physician to visually track the position of the catheter within the patient in real time in conjunction with an image of the patient's anatomy. Some systems can combine EP mapping and IGS functionality, including the CARTO 3® system by Biosense Webster, Inc. (Irvine, California). Examples of catheters configured for use with IGS systems are disclosed in U.S. Pat. No. 9,480,416, entitled "Signal Transmission Using Catheter Braid Wires," issued November 1, 2016, the entire disclosure of which is incorporated herein by reference, and various other references cited herein.

[0008] Although several catheter systems and methods have been made and utilized, it is believed that no one prior to the present inventors has made or utilized the invention as described, illustrated, and claimed herein. [Brief explanation of the drawings]

[0009] The drawings and detailed description that follow are merely exemplary and are not intended to limit the scope of the invention(s) contemplated by the inventors. [Figure 1] 1A-1C show schematic diagrams of a medical procedure for inserting a catheter of a catheter assembly into a patient. [Figure 2] 2 shows a perspective view of a distal portion of the catheter of FIG. 1, showing additional components in schematic form. [Figure 3] 2 shows a perspective view of the distal portion of the catheter of FIG. 1 with the outer sheath removed to reveal the internal components. [Figure 4] 2 shows an exploded perspective view of the distal portion of the catheter of FIG. 1. [Figure 5] 1 shows a schematic diagram of another medical procedure in which a catheter assembly is inserted into a patient and an irrigation fluid monitor and alarm are connected to a fluid source. [Figure 6A] FIG. 6 shows a front view of the irrigation fluid monitor and alarm of FIG. 5. [Figure 6B] 6 shows a front view of the irrigation fluid monitor and alarm of FIG. 5 coupled with a fluid bag filled with irrigation fluid. [Figure 6C] 6 shows a front view of the irrigation fluid monitor and alarm of FIG. 5 connected to a fluid bag that has been emptied of irrigation fluid. [Figure 7] 6 shows a perspective view of the irrigation fluid monitor and alarm of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following description of specific examples of the present invention should not be used for purposes of limiting the scope of the invention. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, and not by way of limitation, the principles of the present invention. Other examples, features, aspects, embodiments, and advantages of the present invention will become apparent to those skilled in the art from the following description, which illustrates, by way of example, one of the best modes contemplated for carrying out the invention. As will be understood, the present invention is capable of other different or equivalent aspects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

[0011] Any one or more of the teachings, expressions, variations, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, variations, examples, etc. described herein. Accordingly, the teachings, expressions, variations, examples, etc. described below should not be considered in isolation from one another. Various suitable ways in which the teachings herein can be combined will be readily apparent to those skilled in the art in light of the teachings herein. Such modifications and variations are intended to be included within the scope of the claims.

[0012] As used herein, the term "about" or "approximately" in reference to any numerical value or range of values ​​indicates a suitable tolerance of dimensions that allows a portion of a component or a collection of components to function for the intended purpose described herein. More specifically, "about" or "approximately" may refer to a range of values ​​of ±10% of the recited value; for example, "about 90%" may refer to a range of values ​​of 81% to 99%. Furthermore, as used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject, and are not intended to limit the use of the systems or methods described above to humans, although use of the present invention in human patients represents a preferred embodiment.

[0013] I. Overview of an Exemplary Ablation Catheter System As mentioned above, Figure 1 illustrates an exemplary medical procedure and associated components of a cardiac ablation catheter system that may be used to perform cardiac ablation. Specifically, Figure 1 illustrates a physician (PH) grasping the handle (110) of a catheter assembly (100), with an end effector (140) of a catheter (120) of the catheter assembly (100) disposed within a patient (PA) (shown in Figures 2 and 4, but not shown in Figure 1) for ablation of tissue within or near the patient's (PA) heart (H). The catheter assembly (100) includes the handle (110), the catheter (120) extending distally from the handle (110), the end effector (140) located at the distal end of the catheter (120), and a user input feature (190) located on the handle.

[0014] As described in more detail below, the end effector (140) includes various components configured to deliver RF energy to a target tissue site, provide EP mapping functionality, track applied forces on the end effector (140), track the position of the end effector (140), and distribute irrigation fluid. Also, as described in more detail below, the user input feature (190) is configured to deflect the end effector (140) and a distal portion of the catheter (120) away from a central longitudinal axis (LL) (FIGS. 3-5) defined by a proximal portion of the catheter (120).

[0015] As shown in FIG. 2, the catheter 120 includes an elongated, flexible sheath 122, with an end effector 140 disposed at the distal end of the sheath 122. The end effector 140 and various components housed within the sheath 122 are described in more detail below. The catheter assembly 100 is coupled to a guided drive system 10 via a cable 30. The catheter assembly 100 is also coupled to a fluid source 42 via a fluid conduit 40. A set of magnetic field generators 20 are positioned below the patient PA and are coupled to the guided drive system 10 via another cable 22. The magnetic field generators 20 are merely optional.

[0016] The guidance drive system (10) of this example includes a console (12) and a display (18). The console (12) includes a first driver module (14) and a second driver module (16). The first driver module (14) is coupled to the catheter assembly (100) via a cable (30). In some variations, the first driver module (14) is operable to receive EP mapping signals acquired via microelectrodes (138) of the end effector (140), as described in more detail below. The console (12) includes a processor (not shown) that processes such EP mapping signals, thereby performing EP mapping, as is known in the art.

[0017] The first driver module (14) of this embodiment is further operable to supply RF power to the distal tip member (142) of the end effector (140), thereby ablating tissue, as described in more detail below. The second driver module (16) is coupled to the magnetic field generator (20) via a cable (22). The second driver module (16) is operable to activate the magnetic field generator (20) to generate an alternating magnetic field around the heart (H) of the patient (PA). For example, the magnetic field generator (20) may include a coil that generates an alternating magnetic field within a predetermined working volume that includes the heart (H).

[0018] The first driver module 14 is also operable to receive position-indicating signals from a navigational sensor assembly 150 within the end effector 140. In this variation, the processor of the console 12 is also operable to process the position-indicating signals from the navigational sensor assembly 150 and thereby determine the position of the end effector 140 within the patient (PA). As described in more detail below, the navigational sensor assembly 150 includes a pair of coils on each panel 151 operable to generate signals indicative of the position and orientation of the end effector 140 within the patient (PA). The coils are configured to generate electrical signals in response to the presence of an alternating electromagnetic field generated by the magnetic field generator 20. Other components and techniques that can be used to generate real-time position data associated with the end effector 140 include radio triangulation, acoustic tracking, optical tracking, inertial tracking, etc. Alternatively, the end effector 140 may not include a navigational sensor assembly 150.

[0019] The display 18 is coupled to the processor of the console 12 and is operable to render an image of the patient's anatomy. Such an image may be based on a set of pre- or intra-operatively acquired images (e.g., CT or MRI scans, 3D maps, etc.). The view of the patient's anatomy provided through the display 18 may also change dynamically based on signals from the navigation sensor assembly 150 of the end effector 140. For example, as the end effector 140 of the catheter 120 moves within the patient (PA), corresponding position data from the navigation sensor assembly 150 may cause the processor of the console 12 to update the view of the patient's anatomy in the display 18 in real time, depicting the region of the patient's anatomy surrounding the end effector 140 as it moves within the patient (PA). Additionally, the processor of the console 12 may drive the display 18 to show the location of abnormal conductive tissue sites as detected by electrophysiological (EP) mapping with the end effector 140 or as otherwise detected (e.g., using an EP mapping catheter, etc.). The processor of the console 12 may also drive the display 18 to overlay the current position of the end effector 140 on an image of the patient's anatomy, for example, by overlaying an illuminated dot, crosshairs, or some other form of visual representation of the end effector 140.

[0020] The fluid source 42 in this example includes a bag containing saline or some other suitable irrigation fluid. The conduit 40 includes flexible tubing further coupled to a pump 44 operable to selectively convey fluid from the fluid source 42 to the catheter assembly 100. As described in more detail below, such irrigation fluid may be delivered through an opening 158 in the distal tip member 142 of the end effector 140. Such irrigation may be provided in any suitable manner, as will be apparent to those skilled in the art in view of the teachings herein.

[0021] II. Exemplary End Effectors of Catheter Assemblies 2-4 show exemplary components of the end effector (140) and other components of the distal portion of the catheter (120) in more detail. The end effector (140) includes a distal tip member (142), a distal tip base (144), a distal circuit disk (146), a strain gauge assembly (148), a navigation sensor assembly (150), a distal spacer stack (152), and a pair of proximal spacers (154). The distal tip member (142), the distal tip base (144), the distal circuit disk (146), the strain gauge assembly (148), the navigation sensor assembly (150), the distal spacer stack (152), and the proximal spacers (154) are coaxially aligned with one another and longitudinally stacked such that these components (144-154) define a stacked circuit. A pair of push-pull cables (160, 170) and an irrigation tube (180) extend along the length of the catheter (120) to the end effector (140). Each of these components is described in more detail below. A flexible sheath (122) surrounds all of the aforementioned components, except for the distal tip member (142).

[0022] As shown in FIGS. 3-4, the distal tip member 142 of this embodiment includes a cylindrical body 156 that is electrically conductive and has a dome-tip. A plurality of openings 158 are formed through the cylindrical body 156 and communicate with the hollow interior of the distal tip member 142. The openings 158 thus allow irrigation fluid to be transmitted from the interior of the distal tip member 142 through the cylindrical body 156 and out. The cylindrical body 156 and dome-tip are also operable to apply RF electrical energy to tissue, thereby ablating the tissue. Such RF electrical energy may be transmitted from the first driver module 14 to the proximal-most spacer 154 via the cable 30. The distal tip member 142 may also include one or more thermocouples configured to provide temperature sensing capabilities.

[0023] As shown in Figures 3-4, the distal tip member (142) of this embodiment also includes one or more EP mapping microelectrodes (138) mounted on the cylindrical body (156). The EP mapping microelectrodes (138) are configured to pick up electrical potentials from tissue in contact with the EP mapping microelectrodes (138). The first driver module (14) can process the EP mapping signals and provide corresponding feedback to the physician (PH) indicating the location of abnormal electrical activity in accordance with the teachings of the various references cited herein.

[0024] The strain gauge assembly (148) is positioned proximal to the distal circuit disc (146) and is configured to sense external forces impinging on the distal tip member (142). When the distal tip (142) encounters external forces (e.g., when the distal tip (142) is pressed against tissue), these external forces are transmitted from the distal end (142) to the distal tip base (144), the distal circuit disc (146), and the strain gauge assembly (148) so that the strain gauges can generate suitable signals corresponding to the magnitude and direction of the external forces.

[0025] The navigation sensor assembly 150 can generate signals that indicate the position and orientation of the end effector 140 in three-dimensional space with substantial accuracy. Signals from the navigation sensor assembly 150 can be transmitted through vias or other structures in layers proximate the strain navigation sensor assembly 150 and ultimately to the first driver module 14 of the console 12 via the cable 30.

[0026] As discussed above and shown in Figures 1-2, cable 30 connects catheter assembly 100 to drive system 10. As shown in Figure 4, wires 32 of cable 30 extend along the length of catheter 120 to the most proximal spacer 154.

[0027] As also described above, the catheter assembly (100) is configured to allow irrigation fluid to be transmitted from the fluid source (42) to the catheter (120) via the fluid conduit (40), thereby providing for evacuation of the irrigation fluid through the opening (158) in the distal tip member (142). In this embodiment, the fluid path for the irrigation fluid includes the irrigation tube (180) shown in FIGS. 3-4. The proximal end of the irrigation tube (180) is coupled to the fluid conduit (40) (e.g., at the handle (110) of the catheter assembly (100)). The irrigation tube (180) extends along the length of the catheter (120) to the end effector (140). In some variations, irrigation fluid can be transmitted from the distal end of the irrigation tube (180) through a central passage by being aligned with the above-mentioned central aperture, and ultimately reach the interior of the distal tip member (142) through the aperture (158) in the distal tip base (144).

[0028] As described above and shown in Figures 2-4, the catheter 100 of this embodiment further includes a pair of push-pull cables 160, 170. The push-pull cables 160, 170 allow the physician PH to selectively laterally deflect the end effector 140 away from the longitudinal axis LL, thereby allowing the physician PH to actively steer the end effector 140 within the patient PA. Various mechanisms that can be used to simultaneously drive the push-pull cables 160, 170 in a longitudinally opposed manner will be apparent to those skilled in the art in view of the teachings herein.

[0029] III. Exemplary Irrigation Fluid Monitors and Alarms As described above, the distal tip (142) of the end effector (140) defines a plurality of openings (158) configured to allow irrigation fluid to be transferred from the interior to the exterior of the distal tip member (142). Also, as described above, the end effector (140) is configured to be disposed in or near the heart (H) of a patient (PA) to ablate tissue. Accordingly, during exemplary use, the pump (44) may drive irrigation fluid from the fluid source (42), through the conduit (40) and the irrigation tubing (180), and into the interior of the distal tip member (142) such that the irrigation fluid from the fluid source (42) may flow out of the plurality of openings (158) in or near the heart (H) of the patient (PA).

[0030] In accordance with the above, during use of the catheter assembly 100, if irrigation fluid is sufficiently depleted from the fluid source 42, the pump 44 may attempt to drive air from the empty fluid source 42 rather than the intended irrigation fluid. If air is pumped through the conduit 40, the irrigation tubing 180, and out of the multiple openings 158 at the distal tip 142 of the end effector 140, the end effector 140 being disposed in or near the heart H of the patient PA, the pumped air may cause undesirable results, such as air embolism. Therefore, it may be desirable to automatically shut off the pump 44 when the fluid source 42 is sufficiently empty of irrigation fluid or is about to be sufficiently empty of irrigation fluid.

[0031] During exemplary use of the catheter assembly 100, irrigation fluid may be used to sufficiently cool the end effector 140 or surrounding tissue in response to activating the end effector 140 with RF energy, as described above. During use, if irrigation fluid is sufficiently depleted from the fluid source 42, activating the end effector 140 with RF energy may cause undesirable results, such as excessive tissue ablation or excessive heat spread to adjacent tissue. Therefore, it may be desirable to automatically prevent the end effector 140 from activating RF energy when the irrigation fluid in the fluid source 42 is sufficiently depleted or is about to be sufficiently depleted.

[0032] 5 illustrates a physician (PH) utilizing a catheter assembly (100) in conjunction with an inductive drive system (10), magnetic field generator (20), fluid source (42), and pump (44) similar to those illustrated in FIG. 1, except for the additional use of an exemplary irrigation fluid monitor (200). Specifically, during exemplary use, the fluid monitor (200) is coupled to the fluid source (42) such that the fluid monitor (200) supports the weight of the fluid source (42). As described in more detail below, the fluid monitor (200) is configured to monitor the amount of irrigation fluid contained within the fluid source (42). Also, as described in more detail below, when the fluid monitor (200) detects the amount of irrigation fluid in the fluid source (42) below a predetermined threshold volume / weight, the fluid monitor (200) is configured to shut off the pump (44), shut off RF energy delivered to the end effector (140), generate an audible alarm, or any suitable combination of the above actions.

[0033] As best seen in Figure 6B, fluid source 42 includes fluid bladder 45 that is initially filled with irrigation fluid 50. A lower portion of fluid bladder 45 includes fluid outlet 47 configured to fluidly couple the interior of fluid bladder 45 with fluid conduit 40 via coupler 46. Thus, irrigation fluid 50 can travel from the interior of fluid bladder 45 through coupler 46 and fluid outlet 47 into fluid conduit 40.

[0034] The upper portion of fluid bladder 45 defines a top opening 48 configured to receive fluid bladder connection hook 204 of fluid monitor 200 such that connection hook 204 supports the weight of fluid bladder 45. In this embodiment, hook 204 is used to connect fluid bladder 45 to fluid monitor 200, although any other suitable connection may be used as would be apparent to one of ordinary skill in the art in view of the teachings herein. Top opening 48 may be fluidly isolated from irrigation fluid 50 contained within fluid bladder 45.

[0035] In this embodiment, the fluid monitor 200 is supported by the IV electrode 60 via an upper coupler hook 206. However, the upper coupler hook 206 may have any other suitable connection, as would be apparent to one of ordinary skill in the art in view of the teachings herein. Furthermore, the fluid monitor 200 may be attached to any suitable structure, as would be apparent to one of ordinary skill in the art in view of the teachings herein. In some cases, the fluid monitor 200 may be a freestanding structure.

[0036] As best seen in FIG. 7 , the fluid monitor (200) includes a casing (202), a fluid bag connection hook (204), an upper connection hook (206), an audible alarm (208), a user input assembly (210), a digital display (220), a signal output driver circuit (240), and a signal generating loop assembly (250). The casing (202) houses the connection hooks (204, 206), the audible alarm (208), the user input assembly (210), the digital display (220), the signal output driver circuit (240), and the signal generating loop assembly (250) so that the fluid monitor (200) can operate as a single unit. In some variations, the signal output driver circuit (240) may include a load cell analog circuit providing a range of about 4 mA to about 20 mA. For example, when zero mass is present, the signal output driver circuit 240 outputs 4 mA, and when at full load (e.g., as determined by a user interface provided to a doctor or nurse), the signal output driver circuit 240 outputs a 20 mA signal.

[0037] The audible alarm 208 is in electrical communication with the receiver 254 of the signal generating loop assembly 250. The audible alarm 208 is configured to generate a noise when activated. As described in more detail below, when the receiver 254 measures a current in the signal generating loop assembly 250 that is indicative of the fluid source 42 containing an amount of irrigation fluid 50 below a predetermined threshold volume / weight, the receiver 254 is configured to activate the audible alarm 208, thereby notifying the physician (PH).

[0038] Digital display 220 is in electrical communication with receiver 254 of signal generating loop assembly 250. Digital display 220 is configured to display a value indicative of the amount of irrigation fluid 50 in fluid source 42 based on the current in signal generating loop assembly 250 measured by receiver 254. Digital display 220 may display the value indicative of the amount of irrigation fluid 50 in the fluid source in any suitable units, as would be apparent to one of ordinary skill in the art in view of the teachings herein. For example, digital display 220 may be configured to display the value in grams, milliliters, etc.

[0039] The user input assembly 210 is also in electrical communication with the receiver 254 or the signal generating loop assembly 250. The user input assembly 210 includes a zeroing button 212, a span button 214, an adjustment control 216, a power button 218, and an alarm button 215. The power button 218 is configured to start and stop the irrigation fluid monitor 200. The alarm button 215 may be pressed to stop the audible alarm 208.

[0040] The zeroing button 212, the span button 214, and the adjustment button assembly 216 are configured to calibrate the receiver 254 so that the signal measured by the receiver 254 is proportional to the amount of irrigation fluid 50 in the fluid source 42. For example, as shown in FIG. 6A , before using the fluid source 42 with the pump 44 in accordance with the description herein, the physician PH can press the zeroing button 212, thereby communicating to the receiver 254 the weight measured on the hook 204 at that moment, thereby correlating it to the unweighted hook 204. Next, as shown in FIG. 6B , the physician PH can also couple a filled fluid bladder 45 to the hook 204 and then press the span button 214, thereby communicating to the receiver 254 the weight measured on the hook 204 at that moment, thereby correlating it to the filled fluid bladder 45. If the physician (PH) is carrying a partially filled fluid bag (45), they can use the adjustment control (216) to input how much fluid (50) is in the bag (45) and thereby communicate to the receiver (254) the weight measured on the hook (204) at that moment.

[0041] The signal output driver circuit 240 is in electrical communication with the receiver 254. The signal output driver circuit 240 is coupled to a pump communication wire 70 and a first driver module communication wire 72. The pump communication wire 70 is electrically coupled to the pump 44 such that the receiver 254 can transmit signals to the pump 44 via the signal output driver circuit 240 and wire 70. Similarly, the first driver module communication wire 72 is electrically coupled to the first driver module 14 such that the receiver 254 can transmit signals to the first driver module 14 via the signal output driver circuit 240 and wire 72.

[0042] The receiver 254 can be in bidirectional communication with both the pump 44 and the first driver module 14 such that the pump 44 and the first driver module 14 can transmit information to the receiver 254. The signal output driver circuit 240 can be selectively coupled to the pump communication wire 70 and the first driver module communication wire 72. Alternatively, the signal output driver circuit 240 can be permanently attached to the pump communication wire and the first driver module communication wire 72.

[0043] As described in more detail below, the receiver (254) can send a signal to the pump (44) and the first driver module (14) to stop the pump (44) and prevent the first driver module (14) from activating the end effector (140) with RF energy when the receiver (254) measures an electrical signal in the signal generating loop assembly (250) that indicates the fluid source (42) contains an amount of irrigation fluid (50) that is less than a predetermined threshold volume / weight.

[0044] The signal generating loop assembly 250 includes a power source 252, a receiver 254, and a load cell assembly 255. As described in more detail below, the signal generating loop assembly 250 is configured to generate an electrical signal indicative of the amount of irrigation fluid 50 contained within the fluid bladder 45. Furthermore, as described in more detail below, the signal generating loop assembly 250 is configured to transmit the electrical signal indicative of the amount of irrigation fluid 50 contained within the fluid bladder 45 to the audible alarm 208, the digital display 220, and the signal output driver circuit 240.

[0045] Power source 252 is configured to electrically power other suitable components of fluid monitor 200. Power source 252 may include any suitable type of battery, as would be apparent to one of ordinary skill in the art in view of the teachings herein. Additionally or alternatively, power source 252 may be configured to couple to an external source of power, such as console 12, a generator, a wall outlet, or the like. In some cases, power source 252 may be configured to couple to an external power source to charge the battery of power source 252. Power source 252 may be in direct communication with audible alarm 208, digital display 220, user input assembly 210, or the like. Alternatively, there may be a first power source 252 within signal generation loop assembly 250 and a second power source that electrically powers all other components of irrigation fluid monitor 200.

[0046] The power source 252 is electrically coupled to the receiver 254 and the load cell assembly 255 via the electrical coupling 260 to form the signal generating loop assembly 250. During exemplary use, the power source 252 is capable of generating sufficient power to produce an electrical signal that travels through the signal generating loop assembly 250. As described in more detail below, the load cell assembly 255 is configured to modify the electrical signal that travels through the signal generating loop assembly 250 in response to a load supported by the hook 204.

[0047] Receiver 254 is configured to appropriately process the electrical signal within signal generating loop assembly 250 and transmit a proportional signal to audible alarm 208, digital display 220, and signal output driver circuit 240, as described herein. Receiver 254 may include any suitable components as would be apparent to one of ordinary skill in the art in view of the teachings herein. For example, receiver 254 may be configured in accordance with signal generating loop assembly 250 to provide a 4-20 mA DC loop. Thus, when the load cell assembly (255) is subjected to a load supported by a hook (204) associated with a fluid source (42) filled with irrigation fluid (50), the signal generating loop assembly (250) can generate a current of 20 mA measured by the receiver (254), while when the load cell assembly (255) is subjected to a load supported by a hook (204) associated with a fluid source (42) having an amount of irrigation fluid (50) less than a predetermined threshold volume / weight, the signal generating loop assembly (250) can generate a current of 4 mA measured by the receiver (254).

[0048] The load cell assembly 255 includes a strain gauge assembly 256 and a resilient mechanical ground 258. The strain gauge assembly 256 may include any suitable component(s) as would be apparent to one of ordinary skill in the art in view of the teachings herein. Similarly, the resilient mechanical ground 258 may include any suitable material, such as any suitable metal, alloy, or the like, as would be apparent to one of ordinary skill in the art in view of the teachings herein.

[0049] The strain gauge assembly (256) is secured to the resilient mechanical ground (258), which in turn is secured to the casing (202). The fluid coupling hook (204) is coupled to the resilient mechanical ground (258) such that a load supported by the fluid coupling hook (204) is in turn supported by the resilient mechanical ground (258). Specifically, a load transferred from the fluid coupling hook (204) to the resilient mechanical ground (258) can elastically deform the resilient mechanical ground (258) in proportion. Thus, when the fluid coupling hook (204) supports the fluid source (42), the weight of the fluid source (42) can elastically deform the resilient mechanical ground (258) in proportion to the amount of irrigation fluid (50) contained within the fluid source (50). Thus, in accordance with the description herein, as irrigation fluid 50 is depleted from fluid source 42, the elastic deformation of mechanical ground 258 changes proportionately. In other words, the more irrigation fluid 50 there is in fluid source 42 coupled to hook 204, the greater the elastic deformation of mechanical ground 258, and conversely, the less irrigation fluid 50 there is in fluid source 42 coupled to hook 204, the less the elastic deformation of mechanical ground 258.

[0050] The strain gauge assembly 256 is electrically coupled to both the receiver 254 and the power source 252 via an electrical coupling 260 such that the electrical signal in the loop 250 travels through the strain gauge assembly 256. Because the strain gauge assembly 256 is attached to a mechanical ground 258, the strain gauge assembly 256 also elastically deforms in response to the mechanical ground 258 supporting the fluid source 42, as described above. The elastic deformation of the strain gauge assembly 256 changes the resistance of the strain gauge assembly 256, which in turn modifies the electrical signal traveling through the signal generating loop assembly 250. The change in resistance of the strain gauge assembly 256 and the electrical signal traveling through the signal generating loop assembly 250 may be proportional to the elastic deformation of the elastic mechanical ground 258 and, therefore, may be proportional to the amount of irrigation fluid 50 in the irrigation source 42.

[0051] Thus, as shown in Figure 6B, the signal generating loop assembly (250) can generate a first signal (e.g., a current value) measured by the receiver (254) when the irrigation fluid (50) of the fluid source (42) is full, while the signal generating loop assembly (250) can generate a second signal (e.g., a current value) by the receiver (254) when the fluid source (42) is below a predetermined threshold volume / weight of irrigation fluid (50), such as when the irrigation fluid (50) is empty, as shown in Figure 6C. Additionally, the signal generating loop assembly (250) can generate a proportional current value measured by the receiver (254) when the fluid source (42) is between full and the predetermined threshold volume / weight.

[0052] In an example where the signal generating loop assembly (250) is a 4-20 mA DC loop, the receiver (254) may measure a current of 20 mA when the irrigation fluid (50) in the fluid source (42) is full, while the receiver (254) may measure a current of 4 mA when the irrigation fluid in the fluid source (42) is empty or is below a predetermined threshold volume / weight of the irrigation fluid (50).

[0053] By proportionally responding the current measured in the signal generating loop assembly 250 based on the load (i.e., the volume / weight of irrigation fluid 50 in the fluid source 42) supported by the hook 204, the receiver 254 may be configured to determine the volume / weight within the fluid source 42 from the current measured in the signal generating loop assembly 250. While in this example, a current value is utilized to identify the load supported by the hook 204, other variations can provide different variations in the electrical signal (e.g., voltage, resistance, capacitance, inductance, etc.) to represent different loads supported by the hook 204. Other suitable electrical signal protocols and corresponding sensing hardware that can be used will be apparent to those skilled in the art in view of the teachings herein.

[0054] The receiver 254 may transmit the measured current in the loop assembly 250, indicating the amount of irrigation fluid 50 remaining in the fluid bladder 45 (or the associated volume / weight in the fluid source 42 corresponding to the measured current), to the digital display 220, so that the physician may be able to directly view the amount of irrigation fluid 50 remaining in a particular fluid bladder 45 during an exemplary procedure. The receiver 254 may also transmit the measured current in the loop assembly 250, indicating the amount of irrigation fluid 50 remaining in the fluid bladder 45 (or the associated volume / weight corresponding to the measured current), to the first driver module 14, the pump 44, and the audible alarm 208.

[0055] When the irrigation fluid 50 in the fluid source 42 falls below a predetermined threshold volume / weight, the receiver 254 can send a signal to the first driver module 14 that atomically prevents the driver module 14 from activating the end effector 140 with RF energy. Thus, the irrigation fluid monitor 200 can prevent the end effector 140 from generating excessive temperature or excessive tissue ablation.

[0056] Additionally, if irrigation fluid 50 in fluid source 42 falls below a predetermined threshold volume / weight, receiver 254 may transmit a similar signal to pump 44 that automatically prevents pump 44 from pumping fluid from fluid source 42 and out of plurality of openings 158, in accordance with the above. Irrigation fluid monitor 200 may thus help prevent pump 44 from inadvertently pumping air through conduit 40, irrigation tubing 180, and out of plurality of openings 158.

[0057] Similarly, when the irrigation fluid (50) in the fluid source (42) falls below a predetermined threshold volume / weight, the receiver (254) can send a signal to an audible alarm (208), which can be activated to alert the physician (PH) to the fact that more irrigation fluid (50) is needed.

[0058] In an example where the signal generating loop assembly (250) is a 4-20 mA DC loop, the signal configured to stop the pump (44), inhibit the first driver module (14), and activate the audible alarm (208) may be a 4 mA current.

[0059] In this example, the load cell assembly (255) includes a strain gauge (256), although any suitable measurement device may be used as would be apparent to one skilled in the art in view of the teachings herein.

[0060] The irrigation fluid monitor 200 may also include a redundant depletion sensor that can electrically ground the irrigation fluid 50 through the irrigation fluid monitor 200. The depletion sensor is redundant in that the sensor can indicate when the irrigation fluid 50 in the fluid bag 45 is sufficiently empty. By way of example only, such a sensor may include a sterile luer hub with a small chamber containing two small conductive strips (e.g., gold) that are parallel and spaced apart from each other. When a conductive solution (e.g., 0.9% saline) simultaneously contacts both conductive strips, a circuit is completed between these two conductive strips, thus indicating the presence of irrigation fluid. A small amount of current is drawn from one of the strips. When the current is interrupted, an audible alarm (and / or other response) may be initiated.

[0061] IV. Exemplary Combinations The following examples illustrate various, non-exhaustive methods in which the teachings herein can be combined or applied. It should be understood that the following examples are not intended to limit the scope of any claims that may be presented at any time in this application or in a later application related to this application. No disclaimer is intended. The following examples are provided for illustrative purposes only. It is contemplated that the various teachings herein may be configured and applied in many other ways. It is also contemplated that certain features referred to in the following examples may be omitted in some variations. Accordingly, none of the aspects or features referred to below should be considered critical unless later expressly indicated to be so by the inventor or the inventor's successor in interest. If a claim including additional features other than those referred to below is presented in this application or in a later application related to this application, those additional features should not be presumed to have been added for any reasons related to patentability. [Example]

[0062] An apparatus comprising: (b) a fluid bladder support joint configured to support a fluid source; (b) a signal generating assembly coupled to the fluid bladder support joint, the signal generating assembly configured to generate a signal in response to an amount of fluid in the fluid source; and (c) a signal output driver circuit in electrical communication with the signal generating assembly, the signal output driver circuit configured to transmit a signal from the signal generating assembly to an actuation element configured to perform a task, the signal being configured to prevent the actuation element from performing the task when the amount of fluid in the fluid source reaches a predetermined threshold amount. [Example]

[0063] 2. The apparatus of example 1, wherein the signal generating assembly comprises a load cell assembly. [Example]

[0064] 3. The apparatus of any one or more of Examples 1-2, wherein the signal generating assembly comprises a power source. [Example]

[0065] 4. The apparatus of example 3, wherein the signal generating assembly comprises a receiver in electrical communication with the load cell assembly and the power source. [Example]

[0066] 5. The apparatus of example 4, wherein the apparatus comprises a digital display and the receiver is configured to transmit the signal to the digital display. [Example]

[0067] The device of any one or more of Examples 4-5, further comprising an audible alarm, wherein the receiver is configured to activate the audible alarm when the amount of fluid in the fluid source reaches a predetermined threshold amount. [Example]

[0068] 7. The apparatus of any one or more of Examples 1-6, further comprising a user input assembly configured to calibrate the signal generating assembly. [Example]

[0069] 8. The device of example 7, wherein the user input assembly further comprises a power button configured to activate the device. [Example]

[0070] The device of any one or more of Examples 7-8, wherein the input assembly further comprises an alarm button configured to silence the audible alarm. [Example]

[0071] 10. The device of any one or more of Examples 1-9, wherein the signal generating assembly comprises a depletion sensor. [Example]

[0072] 11. The apparatus of any one or more of Examples 1-10, wherein the actuation element comprises a pump in fluid communication with the fluid source, the pump configured to pump fluid from the fluid source. [Example]

[0073] The device of any one or more of Examples 1-11, wherein the actuation element comprises a driver module configured to activate RF energy. [Example]

[0074] 13. The apparatus of any one or more of Examples 1-12, wherein the signal generating assembly comprises a strain gauge. [Example]

[0075] 14. The apparatus of example 13, wherein the signal generating assembly comprises an elastic body secured to the strain gauge. [Example]

[0076] The device of any one or more of Examples 1-14, further comprising a body that encompasses at least a portion of the signal-generating assembly. [Example]

[0077] An apparatus comprising: (b) a fluid bladder support joint configured to support a fluid source; (b) a signal generating assembly coupled to the fluid bladder support joint, the signal generating assembly configured to generate a signal in response to an amount of fluid in the fluid source; and (c) a signal output driver circuit in electrical communication with the signal generating assembly, the signal output driver circuit configured to transmit a signal from the signal generating assembly to a pump in communication with the fluid source, the signal configured to stop the pump when the amount of fluid in the fluid source reaches a predetermined threshold amount. [Example]

[0078] 17. The apparatus of example 16, wherein the signal generating assembly comprises a load cell. [Example]

[0079] The device of any one or more of Examples 16-17, further comprising an audible alarm, wherein the signal generating assembly is configured to activate the audible alarm when the fluid source reaches a predetermined threshold amount. [Example]

[0080] An apparatus comprising: (b) a fluid bladder support joint configured to support a fluid source; (b) a signal generating assembly coupled to the fluid bladder support joint, the signal generating assembly configured to generate a signal in response to an amount of fluid in the fluid source; and (c) a signal output driver circuit in electrical communication with the signal generating assembly, the signal output driver circuit configured to transmit a signal from the signal generating assembly to a driver module configured to generate RF energy, the signal configured to prevent the driver module from generating RF energy when the amount of fluid in the fluid source reaches a predetermined threshold amount. [Example]

[0081] 20. The apparatus of example 19, wherein the signal output driver circuit is configured to selectively couple with the cable, and the cable is configured to selectively couple with the driver module. [Example]

[0082] 1. An apparatus comprising: (a) a body; (b) a fluid bladder support joint configured to support a fluid source; (c) (i) a power source; (ii) a load cell assembly attached to the body and the fluid bladder support joint, at least a portion of the load cell assembly in electrical communication with the power source and configured to generate a signal in response to an amount of fluid in the fluid source; and (ii) a receiver assembly in electrical communication with the power source and the load cell assembly, the receiver assembly configured to transmit a signal from the signal generating assembly to an actuation element configured to perform a task, the signal being configured to prevent the actuation element from performing the task when the amount of fluid in the fluid source reaches a predetermined threshold amount.

[0083] V. Other It should be understood that any of the embodiments described herein may include various other features in addition to or in place of those described above. By way of example only, any of the embodiments described herein may also include one or more of the various features disclosed in any of the various references incorporated herein by reference.

[0084] It should be understood that any one or more of the teachings, expressions, embodiments, examples, etc. described herein can be combined with any one or more of the other teachings, expressions, embodiments, examples, etc. described herein. Thus, the above teachings, expressions, embodiments, examples, etc. should not be considered in isolation from one another. Various suitable ways in which the teachings herein can be combined will be readily apparent to those of ordinary skill in the art in light of the teachings herein. Such modifications and variations are intended to be included within the scope of the claims.

[0085] Any patent, publication, or other disclosure referred to herein as being incorporated by reference, in whole or in part, should be understood to be incorporated herein only to the extent that the incorporated content does not contradict current definitions, opinions, or other disclosures set forth herein. As such, and to the extent necessary, the disclosures explicitly set forth herein shall supersede any conflicting statements incorporated herein by reference. Any content, or portions thereof, that contradicts current definitions, opinions, or other disclosures set forth herein shall be incorporated herein by reference, but only to the extent that no conflict arises between the referenced content and the current disclosure.

[0086] While various variations of the present invention have been shown and described, further applications of the methods and systems described herein may be realized by those skilled in the art through appropriate modifications without departing from the scope of the present invention. While some of these possible modifications have been described, other modifications will be apparent to those skilled in the art. For example, the above-described embodiments, variations, geometries, materials, dimensions, proportions, steps, etc., are illustrative and not required. Accordingly, the scope of the present invention should be considered in light of the following claims and should not be understood to be limited to the details of construction and operation shown and described in this specification and drawings.

[0087] [Embodiment] (1) A device comprising: (a) a fluid bladder support joint configured to support a fluid source; (b) a signal generating assembly coupled to the fluid bladder support joint, the signal generating assembly configured to generate a signal in response to an amount of fluid in the fluid source; (c) a signal output driver circuit in electrical communication with the signal generating assembly, the signal output driver circuit configured to transmit the signal from the signal generating assembly to an actuation element configured to perform a task, the signal configured to prevent the actuation element from performing the task when the amount of the fluid in the fluid source reaches a predetermined threshold amount. (2) The device described in embodiment 1, wherein the signal generating assembly comprises a load cell assembly. (3) The device described in embodiment 1, wherein the signal generating assembly comprises a power source. (4) The apparatus of claim 3, wherein the signal generating assembly comprises a receiver in electrical communication with the load cell assembly and the power source. (5) The device of embodiment 4, wherein the device comprises a digital display and the receiver is configured to transmit the signal to the digital display.

[0088] (6) The device of embodiment 4, further comprising an audible alarm, wherein the receiver is configured to activate the audible alarm when the amount of fluid in the fluid source reaches the predetermined threshold amount. (7) The device described in embodiment 1, further comprising a user input assembly configured to calibrate the signal generating assembly. (8) The device of embodiment 7, wherein the user input assembly further comprises a power button configured to start the device. (9) The device of claim 7, wherein the input assembly further comprises an alarm button configured to silence the audible alarm. (10) The device described in embodiment 1, wherein the signal generating assembly comprises a depletion sensor.

[0089] (11) The device of embodiment 1, wherein the actuating element comprises a pump in fluid communication with the fluid source, the pump configured to pump fluid from the fluid source. (12) The device described in embodiment 1, wherein the actuation element comprises a driver module configured to activate RF energy. (13) The device described in embodiment 1, wherein the signal generating assembly comprises a strain gauge. (14) The device described in embodiment 13, wherein the signal generating assembly comprises an elastic body fixed to the strain gauge. (15) The device described in embodiment 1, further comprising a body that contains at least a portion of the signal generating assembly.

[0090] (16) An apparatus comprising: (a) a fluid bladder support joint configured to support a fluid source; (b) a signal generating assembly coupled to the fluid bladder support joint, the signal generating assembly configured to generate a signal in response to an amount of fluid in the fluid source; (c) a signal output driver circuit in electrical communication with the signal generating assembly, the signal output driver circuit configured to transmit the signal from the signal generating assembly to a pump in communication with the fluid source, the signal configured to stop the pump when an amount of the fluid in the fluid source reaches a predetermined threshold amount. (17) The apparatus of embodiment 16, wherein the signal generating assembly comprises a load cell. (18) The device of embodiment 16, further comprising an audible alarm, wherein the signal generating assembly is configured to activate the audible alarm when the fluid source reaches the predetermined threshold volume. (19) An apparatus comprising: (a) a fluid bladder support joint configured to support a fluid source; (b) a signal generating assembly coupled to the fluid bladder support joint, the signal generating assembly configured to generate a signal in response to an amount of fluid in the fluid source; (c) a signal output driver circuit in electrical communication with the signal generating assembly, the signal output driver circuit configured to transmit the signal from the signal generating assembly to a driver module configured to generate RF energy, the signal configured to prevent the driver module from generating the RF energy when an amount of the fluid in the fluid source reaches a predetermined threshold amount. (20) The device described in embodiment 19, wherein the signal output driver circuit is configured to selectively couple to a cable, and the cable is configured to selectively couple to the driver module.

Claims

1. 1. A cardiac ablation catheter system, comprising:

1. An irrigation fluid monitor comprising: (a) a fluid bladder support joint configured to support a fluid source; (b) a signal generating assembly coupled to the fluid bladder support joint, the signal generating assembly configured to generate a signal in response to an amount of fluid in the fluid source; (c) an irrigation fluid monitor comprising: a signal output driver circuit in electrical communication with the signal generating assembly; a catheter assembly including an end effector configured to deliver radio frequency energy, the distal tip member of the end effector defining a plurality of openings configured to communicate the fluid from an interior to an exterior of the distal tip member; a pump in fluid communication with the fluid source and the catheter assembly, the pump operable to selectively drive the fluid from the fluid source to the catheter assembly; the signal output driver circuit is configured to transmit the signal from the signal generating assembly to the pump, the signal being configured to deactivate the pump and prevent the end effector from delivering the radio frequency energy when the amount of the fluid in the fluid source reaches a predetermined threshold amount; the distal tip member includes an EP mapping microelectrode mounted on a cylindrical body, the EP mapping microelectrode configured to pick up an electrical potential from tissue in contact with the EP mapping microelectrode; system.

2. The system of claim 1 , wherein the signal generating assembly comprises a load cell assembly.

3. The system of claim 2 , wherein the signal generating assembly comprises a power source.

4. The system of claim 3 , wherein the signal generating assembly comprises a receiver in electrical communication with the load cell assembly and the power source.

5. The system of claim 4 , wherein the system comprises a digital display, and the receiver is configured to transmit the signal to the digital display.

6. 5. The system of claim 4, further comprising an audible alarm, the receiver configured to activate the audible alarm when the amount of the fluid in the fluid source reaches the predetermined threshold amount.

7. The system of claim 1 , further comprising a user input assembly configured to calibrate the signal generating assembly.

8. The system of claim 7 , wherein the user input assembly further comprises a power button configured to start the system.

9. The system of claim 7 , wherein the user input assembly further comprises an audible alarm and an alarm button configured to silence the audible alarm.

10. The system of claim 1 , wherein the signal generating assembly comprises a depletion sensor.

11. The system of claim 1 , wherein the signal generating assembly comprises a strain gauge.

12. The system of claim 11 , wherein the signal generating assembly comprises an elastic body secured to the strain gauge.

13. The system of claim 1 , further comprising a body that contains at least a portion of the signal generating assembly.

14. 2. The system of claim 1, wherein the signal output driver circuitry is configured to selectively couple with a cable, and the cable is configured to selectively couple with the signal output driver circuitry.

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