Systems and methods for reducing leakage from catheters - Patents.com

Abstract

To provide systems, methods and devices for preventing leakage in an intracardiac blood pump system.SOLUTION: An intracardiac blood pump system comprises a pump, an elongate multi-lumen catheter, a compartment connected to the catheter, a first lumen, a conduit and a filter disposed within the conduit. The filter is configured to prevent egress of liquid from the multi-lumen catheter into the compartment after allowing a flow of gas from a first end of the conduit through a second end of the conduit and into the multi-lumen catheter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] REFERENCE TO RELATED APPLICATIONS This application claims priority to and benefit of U.S. Provisional Patent Application No. 62 / 700,683, entitled "SYSTEMS AND METHODS FOR REDUCING LEAKS FROM A CATHETER," filed July 19, 2018, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] background Intracardiac heart pump assemblies can be introduced surgically or percutaneously into the heart and are used to deliver blood from one location within the heart or circulatory system to another location within the heart or circulatory system. For example, when placed intracardiac, an intracardiac pump can pump blood from the left ventricle of the heart into the aorta or from the right ventricle to the pulmonary artery. Intracardiac pumps are driven by a motor located outside or inside the patient's body. Some intracardiac blood pump systems can operate in parallel with the native heart to supplement cardiac output and partially or fully offload cardiac components. Examples of such systems include the IMPELLA® family of devices (Abiomed, Inc., Danvers, Massachusetts).

[0003] A blood pump system includes a pump and a compartment. A catheter is attached at one end to the pump and at the other end to the compartment. The catheter typically includes multiple fluid lumens that transport fluid distally to the pump. The compartment may be multifunctional. In some applications, the compartment includes mechanical components and electronics that enable the pump to operate and be maintained. Leaks from lumens in the catheter can reach the compartment and compromise the electronic elements therein. For example, leaks can lead to pump shutdown or a reduction in total system pressure. Summary of the Invention

[0004] overview Described herein are systems, methods, and devices for preventing leaks in intracardiac blood pump systems. Such systems can prevent fluid from leaking from a catheter into a compartment of the blood pump system that houses electronic components while maintaining pump functionality. As described herein, a filter is advantageously installed between the catheter and the compartment of the blood pump system to seal the compartments separately. For example, the filter allows sterilizing gas to pass through the filter to the catheter, but prevents liquid from the catheter (e.g., as a result of a leak) from passing through the filter into the compartment.

[0005] In some embodiments, the intracardiac blood pump system includes a pump; a catheter proximal to the pump; a compartment proximal to the catheter; a conduit extending through the interface between the compartment and the catheter; and a filter within the conduit. For example, the blood pump system may be an Impella® device from Abiomed, Inc. or any other suitable system. In some embodiments, a controller is configured to facilitate operation of the blood pump system described herein. For example, the controller may be an Automated Impella Controller (AIC)® from Abiomed, Inc. or any other suitable controller that receives input signals and converts them into operating signals to operate the pump. At least one advantage of a separate controller configured to facilitate operation of the intracardiac blood pump system is tight control of the system and acquisition of data related to the system.

[0006] In some embodiments, the pump includes a housing and a rotor disposed within the housing. The rotor may have at least one blade. In particular, the rotor may include impeller blades shaped to generate fluid flow when subjected to a rotational force. In some embodiments, the rotor is driven by an implantable motor having a rotor and a stator. A proximal end of the rotor may be coupled to a drive shaft. In some embodiments, the motor is external to the patient's body and drives the rotor via an elongated mechanical power transmission element, such as a flexible drive shaft, a drive cable, or a fluid coupling.

[0007] In some embodiments, the catheter is an elongated, multi-lumen catheter having a proximal end, a distal end, and a central lumen. The distal end of the elongated, multi-lumen catheter may be adjacent to the pump housing. For example, when using a blood pump system, the pump housing may be positioned inside the patient's heart, and the elongated, multi-lumen catheter may extend from the patient's heart through the patient's vasculature such that a first portion of the catheter is inside the patient's body and a second portion of the catheter is outside the patient's body. The catheter may include two, three, four, five, or any suitable number of lumens. For example, two separate tubes may pass through the central lumen of the catheter, thus defining a total of three lumens: a first central lumen, a lumen through the first tube, and a lumen through the second tube. Some lumens may extend the entire length of the catheter, while other lumens may extend only partially through the catheter.

[0008] In some embodiments, the compartment is proximal to the proximal end of the catheter. For example, the distal end of the compartment may be positioned adjacent to the proximal end of the catheter. At least one advantage of locating the compartment adjacent to the proximal end of the catheter is that tubing can extend through the compartment and into the lumen of the catheter. In some instances, the catheter may extend partially into the compartment (e.g., to provide structural support at the connection point between the catheter and the compartment). In some instances, the proximal end of the catheter abuts the distal end of the compartment.

[0009] In some embodiments, the blood pump system further includes a connector at the interface between the compartment and the catheter. The first lumen and the conduit may pass through the connector. In some embodiments, the connector has an interior volume, and the filter occupies at least 50 percent of the interior volume of the connector. In some examples, the connector extends partially into the compartment. In some examples, the catheter extends partially into the connector. At least one advantage of providing a connector between the compartment and the catheter is that it provides additional structural stability at the connection point between these two elements. For example, the connector may prevent the catheter from making sharp bends or kinking where it connects to the compartment.

[0010] In some embodiments, the compartment comprises a first opening and one or more side ports. The first opening of the compartment may be located at the distal end of the compartment and connected to the proximal end of the catheter. The one or more side ports of the compartment may be located proximal to the first opening of the compartment. For example, one or two side ports may be located between the distal and proximal ends of the compartment. At least one advantage of providing a side port is that it allows a fluid-transporting lumen to enter the compartment and then extend into the proximal end of the catheter. In particular, the side port provides connection to an external fluid source that can provide fluid to a pump or patient through the catheter.

[0011] In some embodiments, at least one electronic element resides within the compartment. The at least one electronic element may include a memory, a pressure transducer, and / or a pressure sensor. For example, a printed circuit board with transistors, inductors, resistors, capacitors, sensors, or any other suitable elements may be disposed within the compartment. The electronics within the compartment may also allow the pump to be connected to a pump controller. At least one advantage of housing a memory element within the compartment is that the blood pump system can store operating parameters when the pump is connected to multiple controllers at different times. At least one advantage of housing a pressure transducer and / or pressure sensor within the compartment is that the pump system can "translate" pressure readings (e.g., from a pressure transducer) so that a pressure signal or related parameters can be sent to the controller and displayed to the user.

[0012] In some embodiments, the first lumen of the elongate, multi-lumen catheter is configured to transfer fluid from an external source. The fluid may be transferred through one or more side ports in the compartment, through a first opening in the compartment, and to the distal end of the elongate, multi-lumen catheter. In some embodiments, the first lumen passes through the compartment. For example, the first lumen may be defined by a first end point outside the compartment, extend through a portion of the compartment into the catheter, and terminate at a second end point within the catheter or at the distal end of the catheter. In some embodiments, the first lumen is within the central lumen. At least one advantage of locating the first lumen within the central lumen is that it provides a single tube that contains all other tubes extending from the compartment, preventing tangling and / or kinking of the tubing. Additionally, by locating the first lumen within the central lumen, the first lumen is protected from external forces (e.g., cuts, etc.) by an additional layer of tubing.

[0013] In some embodiments, the fluid is blood, saline, a purge fluid, glucose, heparin, or any other suitable substance, or a combination thereof. For example, the fluid may include dextrose and heparin. In some embodiments, the fluid includes a purge fluid, which flows through the first lumen and into the rotor to maintain the pump substantially free of blood. At least one advantage of using a purge fluid is that the flow of the purge fluid can provide a barrier to blood ingress into the gap between the rotor and the motor stator or pump housing, which could otherwise cause damage to the blood (e.g., hemolysis) or motor (e.g., increased friction, overheating, and / or seizing). For example, the purge fluid may include dextrose and heparin. At least one advantage of using a combination of dextrose and heparin is that it prevents clot formation (e.g., with the anticoagulant heparin) with an appropriate amount of active agent while maintaining biocompatibility and flow.

[0014] In some embodiments, the blood pump system further includes a second lumen of the elongate multi-lumen catheter. The second lumen may be configured to transport a second liquid. In some examples, the second lumen extends through the compartment. The second fluid may also be transported from an external source through one or more side ports of the compartment, through the first opening of the compartment, and to the distal end of the elongate multi-lumen catheter. In some examples, the second lumen is a pressure lumen, and the second fluid is saline. The second lumen may have an opening located distal to the compartment. At least one advantage of the second lumen is that the second lumen may transport a different fluid from the first lumen, which may be provided via a different external source. For example, the first lumen may transport a purge fluid, while the second lumen transports saline, and the purge fluid and saline may be kept separate from each other.

[0015] In some embodiments, the conduit extends through the interface between the compartment and the multi-lumen catheter. The conduit may have a first end positioned proximal to the first opening of the compartment and a second end positioned distal to the first opening of the compartment so as to span the first opening of the compartment. Positioning the conduit within both the compartment and the catheter allows for the insertion of a liquid or gas from the compartment into the catheter, thereby providing access to the central lumen of the catheter. The conduit is configured to transfer gas from the first end of the conduit through the first opening of the compartment to the second end of the conduit. The second end of the conduit may be in fluid communication with the central lumen of the elongated multi-lumen catheter. For example, the proximal end of the conduit may extend a short distance into the compartment, and the distal end of the conduit may extend a short distance into the catheter. The system may be placed in an environment filled with gas introduced via an external gas source, and the conduit may allow the gas to permeate into the catheter. At least one advantage of transferring gas into the catheter is that it sterilizes the central lumen of the catheter so that any fluids within the catheter (e.g., fluids that may come into contact with the patient) are maintained in a sterile condition.

[0016] In some embodiments, the filter is disposed within the conduit. The filter may be configured to prevent fluid from exiting the multi-lumen catheter into the compartment while allowing gas flow from the first end of the conduit through the second end of the conduit into the multi-lumen catheter. At least one advantage of placing the filter within the conduit is that any fluid leakage from within the central lumen of the catheter will reach the filter (via the conduit) before reaching any electronic components within the compartment.

[0017] In some embodiments, the gas transported by the conduit is a sterilizing gas. The sterilizing gas may be used to sterilize the central lumen. For example, the gas may be ethylene oxide, nitrogen dioxide, ozone, vaporized hydrogen peroxide, or any other suitable gas. At least one advantage of using a sterilizing gas is that it sterilizes the central lumen of the catheter so that any fluids within the catheter (e.g., fluids that may come into contact with the patient) are maintained in a sterile state.

[0018] In some embodiments, the filter is configured to prevent leakage of liquid from the central lumen, which may potentially pass through the conduit and reach the compartment. During operation of the blood pump system, the first lumen may be damaged, causing liquid to leak from the first lumen into the central lumen of the catheter. For example, purge fluid may leak from the lumen into the central lumen of the catheter. Without the filter, the leaked liquid would flow from the catheter into the compartment, which would be problematic. However, a filter positioned in the conduit prevents the leaked liquid from reaching the interior of the compartment, thus preventing the fluid from reaching the at least one electronic component. To facilitate sterilization while still achieving a proper seal, the filter is configured to provide liquid screening, thereby allowing gas flow to be transferred across the filter before any liquid contact occurs. At least one advantage of preventing leakage from passing through the filter is that it prevents liquid from reaching the electronic components in the compartment. For example, if liquid were to come into contact with any exposed electronic elements within the compartment, the liquid could cause a short circuit or otherwise damage the electronics, causing the pump to stop or alter operation. At least one advantage of allowing gas to pass through the filter is that it allows the central lumen of the catheter to be sterilized.

[0019] Positioning a filter can help achieve a liquid seal. In some embodiments, the filter is positioned proximal to the first opening of the compartment. For example, the filter may be located entirely within the compartment. In some embodiments, the filter is positioned distal to the first opening of the compartment. For example, the filter may be located entirely outside the compartment. In some embodiments, the filter extends across the first opening of the compartment. In some embodiments, a portion of the filter extends within the compartment. For example, the filter may span the first opening of the compartment such that a first portion of the filter is within the compartment and a second portion of the filter is outside the compartment. At least one advantage of positioning a filter such that it extends across or near the opening of the compartment is that the filter can prevent liquid from contacting the interior of the compartment (and electronic components located therein).

[0020] In some embodiments, the filter comprises a hydrogel attached to the pore walls of the porous substrate. For example, the filter may be a filter such as that described in U.S. Patent Application Publication No. 2004 / 0052689, which is incorporated herein by reference in its entirety. The hydrogel may be a hydrophilic polyurethane, a hydrophilic polyurea, a hydrophilic polyureaurethane, or any suitable material. At least one advantage of using a hydrogel (e.g., a hydrophilic polymer) is that the hydrogel swells in an aqueous solution and retains a significant percentage of the aqueous solution to which it is exposed without dissolving. The porous substrate may be metal, ceramic, glass, organic, inorganic, organic polymer, acrylic polymer, polyolefin, or any suitable material, or combination thereof. At least one advantage of a porous substrate is that it has channels through which gas can flow, facilitating sterilization. At least one advantage of using a filter comprising a hydrogel and a porous substrate is that when placed between two pieces of tubing, the filter can prevent contamination between the two pieces by blocking the flow of aqueous solution between the two pieces.

[0021] In some embodiments, the filter self-seals when exposed to a liquid. For example, the filter may self-seal when exposed to an aqueous medium. In some embodiments, the filter is gas permeable. In some embodiments, self-sealing filters react (i.e., seal) rapidly when exposed to a liquid, causing little or no contamination from solutions in contact with the filter, and can withstand high backpressures (e.g., greater than about 7 psi) before again allowing gas or liquid to pass through. In some embodiments, the filter is biocompatible. At least one advantage of self-sealing filters is their short reaction time, little or no contamination from aqueous solutions in contact with them, and ability to withstand high backpressures.

[0022] In some embodiments, the filter is shaped like a thin cylinder and is sized and shaped to fit within the conduit. In some embodiments, the conduit may be a thin tube. The filter may have an outer diameter equal to the inner diameter of the conduit so as to fit snugly within the conduit. In some embodiments, the filter is shaped like a frustum and is sized and shaped to fit within the conduit. The filter may have a first outer diameter equal to the inner diameter of the conduit so as to fit snugly within the conduit at a first end and then taper to follow the shape of the conduit. At least one advantage of shaping and sizing the filter to fit snugly within the conduit is that any gas or liquid passing through the conduit will come into contact with the filter, and thus the filter may prevent liquid from flowing from one end of the conduit to the other (e.g., from the central lumen of the catheter to the interior of the compartment). The filter may have any other shape (e.g., a disk, a prism, etc.) that corresponds to the shape of the conduit.

[0023] In some embodiments, manufacturing a filter for a blood pump system (e.g., a system described herein) involves coating a support material filtration material with a hydrogel. For example, the filtration material may be fibers, granules, powder, or any other suitable material. At least one advantage of using a filter including a hydrogel and a filtration material is that, when placed between two sections of a conduit, the filter can allow gas flow between the two sections, sterilizing the inside of one of the sections, and preventing liquid contamination if an aqueous solution attempts to flow between the two sections. The blood pump system includes a catheter defining at least one lumen having a lumen cross-section. The coated filtration material can be assembled to form a self-sealing filter sized and shaped to have a cross-section equal to that of the lumen cross-section. At least one advantage of assembling the filter in this manner is that it ensures a snug fit within the lumen so that the filter can block or impede any gas or liquid passing through the conduit. The self-sealing filter may be positioned at the distal end of the sealed compartment. The elongated catheter (defining a lumen) is positioned such that the self-sealing filter extends between the sealed compartment and a portion of the elongated catheter. The filter can thus prevent liquid from flowing from one end of the conduit to the other (e.g., from the central lumen of the catheter to the interior of the compartment). A sterilizing gas is delivered to the elongated catheter via a hollow tube extending through at least a portion of the sealed compartment. At least one advantage of using a sterilizing gas is that it sterilizes the central lumen of the catheter so that any fluids within the catheter (e.g., fluids that may come into contact with the patient) are maintained in a sterile state.

[0024] In some embodiments, a gas is passed through a conduit to sterilize the central lumen of the multi-lumen catheter. The conduit is positioned across a first opening of a compartment. The compartment is positioned adjacent to the proximal end of the catheter. Fluid is passed through the first lumen from an external source to the distal end of the multi-lumen catheter. A self-sealing filter prevents fluid from exiting the multi-lumen catheter into the compartment while allowing gas to flow from the first end of the conduit to the second end of the conduit. At least one advantage of preventing leakage from passing through the filter is that it prevents liquid from reaching electronic components within the compartment. If liquid were to come into contact with any exposed electronic components within the compartment, it could cause a short circuit or otherwise damage the electronics, causing the pump to stop or alter operation. At least one advantage of allowing gas to pass through the filter is that it allows sterilization of the central lumen of the catheter. [Brief explanation of the drawings]

[0025] [Figure 1] 1 illustrates an exemplary blood pump system, according to certain embodiments. [Figure 2] 1 illustrates a compartment with one side port, according to certain embodiments. [Figure 3] 1 illustrates a compartment with two side ports, according to certain embodiments. [Figure 4] 4A-C show self-sealing filters that allow the passage of sterilizing gas and prevent the flow of liquid, according to certain embodiments. [Figure 5] 1 illustrates a lumen within a compartment, according to certain embodiments. [Figure 6] 1 illustrates a flow diagram for manufacturing a leak-proof intracardiac blood pump system, according to certain embodiments. [Figure 7]1 illustrates a flow diagram for preventing leakage from a catheter of an intravascular blood pump, according to certain embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0026] Detailed Description Certain exemplary embodiments will be described to provide a general understanding of the systems, methods, and devices described herein. While the embodiments and features described herein are specifically described for use in connection with a percutaneous blood pump system, it will be understood that all components and other features outlined below may be combined with one another in any suitable manner and may be adapted and applied to other types of cardiac therapy and cardiac assist devices, including cardiac assist devices implanted using a surgical incision. Additionally, while the application of pump elements is described herein with respect to blood pumps, it should be understood that the pump elements may be applied to other pumps in which any type of distally pumped fluid flow may flow proximally and damage electronic components. For example, pumps used in acidic or other corrosive environments may require a purge flow to prevent the ingress of acid that would damage the pump components. While the embodiments and features described herein are specifically described for use in connection with an intracardiac blood pump system, it will be understood that a blood pump system according to the embodiments and features described herein may be used in any vasculature and / or in combination with other systems. For example, the filter systems and arrangements described below may be used in urinary or bladder catheterization systems, right heart cardiac assist systems, intra-aortic balloon pumps, extracorporeal membrane oxygenation devices, left ventricular assist devices, renal assist systems such as cardiac assist devices for regulating renal autoregulation, infusion systems, central venous catheters, or any other suitable system.

[0027] FIG. 1 illustrates an intracardiac blood pump system 150 for use with filters such as filters 216 and 316, described further below in connection with FIGS. 2 and 3. System 150 includes an elongated catheter body (also referred to as an elongated multi-lumen catheter) 110, a pump 140, a compartment 100, a purge side arm 120, and a pressure side arm 130. Purge side arm 120 includes a fitting 122, a pressure reservoir 124, an infusion filter 128, and tubing 126. Pressure side arm 130 includes tubing 136. Pump 140 includes a pump housing 134, a motor housing 102, a cannula 173, a suction head 174, and a flexible protrusion 176. Pump 140 can be inserted into a patient's body by a variety of methods.

[0028] Methods by which the pump 140 can be inserted into a patient include, but are not limited to, using over-the-wire and side-rigger techniques. For example, a first guidewire is inserted into the patient's vasculature, and then a guide catheter is threaded over the first guidewire. The first guidewire is then removed, allowing a second guidewire to be introduced into the guide catheter. For example, the second guidewire may be stiffer than the first guidewire to facilitate backloading the pump onto the guidewire. Once the stiffer guidewire is in place, the pump is threaded over the wire using either the standard over-the-wire or side-rigger technique. The guidewire is removed before actuation of the pump. Alternatively, the guidewire is not removed before actuation. Alternatively, the pump can be backloaded onto a guidewire inserted through the empty space in the pump impeller. In one embodiment, a simple guide lumen 132, as described in, for example, U.S. Patent Nos. 8,814,776, 9,402,942, and 9,750,861, which are incorporated by reference herein in their entireties, is used in combination with a guidewire to allow the pump to be more easily backloaded by passing the guidewire through the impeller void space without damaging the impeller. Prior to actuating the pump, the simple guide lumen 132 is removed, as is the guidewire. In another embodiment, the pump is backloaded on a guidewire without using a simple guide lumen.

[0029] In some embodiments, a purge fluid is delivered to the rotor within the pump 140 to maintain the pump substantially free of blood. As described in more detail below, at least one advantage of using a purge fluid is that the flow of the purge fluid can provide a barrier to blood ingress into the gap between the rotor and the motor stator or pump housing, which could otherwise cause blood damage (e.g., hemolysis) or motor damage (e.g., increased friction, overheating, and / or seizure). The purge fluid may be delivered through a first lumen (e.g., defined by tubing 512 in FIG. 5 ) of the elongate catheter body 110, through the motor housing 102, and to the proximal end of the cannula 173. The first lumen of the elongate catheter body 110 supplies purge fluid from a fluid reservoir (not shown) to the pump 140 via the purge side arm 120. Tube 126 partially defines the first lumen of the elongate catheter body 110. The first lumen passes through compartment 100 (eg, compartments 200, 300 and 500, FIGS. 2, 3 and 5, respectively) into elongate catheter body 110 and may include a connector or fitting.

[0030] In some embodiments, as shown in FIG. 1 , the motor may be “internal” and positioned within the patient's body during pump operation, and may be configured with electrical leads that transmit power to the motor to drive the pump. Alternatively, as previously described, the motor may be positioned outside the patient's body and actuate the rotor via a drive shaft, drive cable, or power transmission. For example, the motor may be positioned within the handle of the pump system (e.g., connected to compartment 100). In some examples, the drive cable may extend through elongate catheter body 110 to a rotor positioned near the proximal end of cannula 173. In some embodiments, the drive shaft, drive cable, or power transmission operates in conjunction with the delivery of a purge fluid as described herein (e.g., through tube 512 of FIG. 5 ).

[0031] A purge fluid flows through the pump to prevent blood cells from entering the pump. Alternatively, or additionally, the purge fluid may function as a lubricant for the pump's bearings (not shown) or as a coolant to dissipate heat generated by the electromagnetic motor coils of the motor stator. The purge fluid may be a lubricant, a coolant, a drug, or any suitable hemocompatible fluid. For example, the purge fluid may be saline, Ringer's solution, glucose solution, heparin, or any other suitable fluid. The purge fluid prevents blood from entering the motor housing 102 during operation of the pump 140. The purge fluid may also prevent blood from entering the elongate catheter body 110. In some embodiments, a highly viscous purge fluid, such as a glucose solution, is used to lubricate the bearings inside the pump 140. In other embodiments, a pharmacological agent is used as a purge fluid to purge blood from the pump and serve a medical purpose. For example, the purge fluid may include heparin to prevent blood clotting. The purge fluid flows through the first lumen of the elongate catheter body 110 and exits the pump 140 at an outlet opening near the proximal end portion of the pump 140. The purge fluid disperses safely into the patient's bloodstream.

[0032] Another lumen in the elongate catheter body 110 (e.g., defined by tubing 516 in FIG. 5 ) may supply pressure fluid to the pump via a pressure side arm 130. The pressure side arm 130 provides fluid to a fluid-filled pressure lumen having an inlet at the proximal end of the motor housing 102. The fluid-filled pressure lumen, in combination with an electronic element positioned within the compartment 100, may be used to determine the placement of the pump relative to the patient's aortic valve. For example, the electronic element may be a pressure transducer that converts the pressure from the pressure lumen into a numerical value that can be output to an external system or display. In some embodiments, a second fluid reservoir or pressure bag (not shown) is connected to the proximal end of the pressure side arm 130 to provide the pressure fluid. The pressure fluid may be the same as or different from the purge fluid. For example, the pressure fluid may be saline, Ringer's solution, glucose, heparin, or any blood-compatible fluid.

[0033] In some embodiments, the blood pump system 150 includes an optical pressure sensor (e.g., a Fabry-Perot optical pressure sensor) positioned distal to the motor. An optical fiber extends proximally along the catheter from the optical pressure sensor. The optical pressure sensor includes a cavity terminating in a thin, pressure-sensitive glass membrane. Light exiting the optical fiber is reflected by the glass membrane and enters the optical fiber. The reflected light is transmitted along the length of the optical fiber to an electronic control element (e.g., within the compartment 100 or a connecting console), which determines a pressure signal based on interference fringes of the reflected light.

[0034] As described in further detail below in connection with FIG. 5 , side ports of compartment 100 allow fluid connection with compartment 100. Purge side arm 120 and pressure side arm 130 connect to compartment 100 at a first side port (e.g., tube 526 in FIG. 5 ) and a second side port (e.g., tube 524 in FIG. 5 ), respectively. A first lumen (defined in part by tube 126) and a second lumen (defined in part by tube 136) extend through compartment 100 and into elongate catheter body 110. In some embodiments, tube 126 connects to a tube within compartment 100 (e.g., tube 512 in FIG. 5 ) at an adhesive joint at or near the first side port, such that the first lumen extends through tube 126, through compartment 100, and through elongate catheter body 110 to deliver purge fluid to pump 140. Similarly, in some embodiments, the tube 136 connects to a different tube within the compartment 100 (e.g., tube 516 in FIG. 5 ) at an adhesive joint at or near the second side port so that a second lumen extends through the tube 136, through the compartment 100, and through the elongated catheter body 110 to deliver pressurized fluid to the pump 140.

[0035] In some embodiments, the first and second lumens of the elongate catheter body 110 are maintained separate from one another. The first and second lumens may extend through a central lumen of the elongate catheter body 110 and may be configured to transfer fluids while keeping the central lumen of the elongate catheter body 110 free of purge fluid and pressure fluid. However, the central lumen of the elongate catheter body 110 may transfer fluid if there is a leak from either the first or second lumen. For example, during operation of the pump, the first lumen may be kinked or accidentally damaged, causing purge fluid to leak from the first lumen into the central lumen of the elongate catheter body 110. If a leak reaches the central lumen of the elongate catheter body 110, two potentially problematic situations may arise: (1) the leaked fluid may reach the patient (e.g., through inlets and outlets in the pump 140), and (2) the leaked fluid may reach the interior of the compartment 100.

[0036] To reduce or eliminate the potential risk to the patient if fluid leaks into the central lumen of the elongate catheter body 110, the central lumen is sterilized using a sterilizing gas. Because the fluid in the first lumen (the purge fluid) and the fluid in the second lumen (the pressure fluid) are hemocompatible, a leak from the first or second lumen does not, in itself, pose a risk to the patient unless the fluid is contaminated (e.g., by microorganisms in the central lumen). Because of this potential risk, the central lumen is sterilized even though fluid is not typically passed through it to reach the flow pump 140.

[0037] To sterilize the central lumen, sterilizing gas is introduced into the central lumen of the elongated catheter body 110 via a conduit (e.g., conduit 214 in FIG. 2 or conduit 314 in FIG. 3 ) that extends through an opening in the compartment 100 and into the elongated catheter body 110. The conduit has a proximal end positioned proximal to the first opening of the compartment 100 and a distal end positioned distal to the first opening. The proximal end of the conduit 214 may be accessed through the interior of the compartment 100, for example, before final assembly of the blood pump system. By inserting the sterilizing gas through the proximal end of the conduit, the sterilizing gas reaches the central lumen of the elongated catheter body 110. In the unlikely event that purge fluid or pressure fluid leaks into the central lumen, the sterilizing gas will ensure that the leaked liquid remains sterile. At least one advantage of sterilizing the central lumen is that if any leaked fluid reaches the patient (e.g., through the distal end of the intracardiac blood pump system 150), the fluid will still be sterile and will not introduce bacteria into the patient's body.

[0038] Because the proximal end of the conduit is positioned inside the compartment 100 while the distal end of the conduit is positioned within the central lumen of the elongate catheter body 110, if liquid were to leak into the central lumen of the elongate catheter body 110, the leaked liquid could potentially reach the conduit. To prevent leaked liquid from passing through the conduit and reaching the interior of the compartment 100 (and the electronic elements disposed therein), a self-sealing filter (e.g., filter 216 in FIG. 2 , filter 316 in FIG. 3 ) is installed in the conduit (e.g., conduit 214 in FIG. 2 , conduit 314 in FIG. 3 ). The self-sealing filter allows gas to flow through the conduit while preventing liquid from flowing in at least one direction through the conduit. The self-sealing filter allows gas to flow through the conduit but prevents liquid from flowing in at least one direction through the conduit by sealing upon contact with liquid. Thus, sterilizing gas exposed to the device prior to any exposure to liquid is able to reach the central lumen of the elongate catheter body 110 through the conduit, but any leaking liquid within the central lumen of the elongate catheter body 110 is unable to reach the interior of the compartment 100. Various embodiments of the filter and blood pump assembly are further described below in connection with Figures 2-5.

[0039] FIG. 2 illustrates a compartment 200 having one side port 228, according to certain embodiments. The compartment 200 is similar to the compartment 100 of FIG. 1 , but includes a single side port for a purge side arm instead of the two side arms described above. The compartment 200 is connected to the catheter 210 with a self-sealing filter 216 to prevent fluid leakage from the catheter 210 from reaching the interior of the compartment 200. For example, the compartment may be an Impella® plug from Abiomed, Inc. A first lumen defined by tubes 226 and 212 extends from the exterior of the compartment 200 through the side port 228. For example, the tube 226 may be similar to the tube 126 described above in connection with FIG. 1 or may be part of a purge side arm similar to the purge side arm 120. A first lumen passes through a portion of the interior of compartment 200, extends through a first opening 250 in the compartment, extends through connector 260, and enters catheter 210. In some embodiments, tubing 212 extends through first opening 250 and through the entire length of catheter 210. In some embodiments, connector 260 is a plastic piece configured to provide support to the proximal end of catheter 210.

[0040] The conduit 214 extends through the opening 250, through the connector 260, and into the catheter 210. As described above, the conduit 214 may allow a gas to permeate the central lumen of the catheter 210. For example, the gas may be a sterilizing gas configured to sterilize the central lumen of the catheter 210. The conduit 214 is in the shape of a thin cylinder and has a relatively short length compared to the length of the catheter 210. A proximal end of the conduit 214 is positioned within the compartment 200 and proximal to the opening 250. A distal end of the conduit 214 is positioned within the catheter 210 and distal to the opening 250. In some embodiments, the conduit 214 is in fluid communication with the central lumen of the catheter 210. The conduit 214 is shown as a cylindrical tube. However, the conduit 214 may be a frustum, a thin cylinder, a curved cylinder, a rectangular prism, or any suitable shape.

[0041] Filter 216 is positioned within conduit 214. In some embodiments, filter 216 is in the shape of a thin cylinder. In some embodiments, filter 216 is sized and shaped to completely fill the inner diameter of conduit 214, such that gas or liquid flowing through conduit 214 contacts filter 216, as described in more detail below in connection with FIG. 5 . Filter 216 allows gas to flow from the proximal end of conduit 214 to the distal end of conduit 214, but prevents liquid from the distal end of conduit 214 from reaching the proximal end of conduit 214. This configuration allows gas (e.g., sterilizing gas) to reach the central lumen of catheter 210 before any exposure to liquid, but prevents liquid (e.g., leaked purge fluid, as described above) from reaching compartment 200. Conduit 214 and filter 216 are positioned such that purge fluid flowing through the first lumen defined by tubes 226 and 212 does not pass through conduit 214 and therefore does not contact filter 216. Thus, purge fluid can continue to pass through catheter 210 to a pump (e.g., pump 140) without being blocked by filter 216.

[0042] At least one electronic element 240 is disposed within compartment 200. Electronic element 240 may include a pressure transducer, pump control circuitry, resistors, capacitors, inductors, transistors, wiring, or any other suitable element. Other electronic elements, such as elements of a printed circuit board (PCB), may also be disposed within compartment 200. A proximal end of compartment 200 (positioned opposite opening 250) may be connected to a power source configured to power electronic element 240, for example. If liquid (e.g., purge fluid leaking from the first lumen and reaching the central lumen of catheter 210) enters the interior of compartment 200, the liquid may short out or otherwise damage electronic element 240. For example, if the electronic element corrodes due to fluid damage, the operation and functionality of the pump may be impaired or may stop completely, which may be dangerous to the patient. Filter 216 prevents fluid from reaching the electronic element. In some embodiments, filter 216 is impermeable to liquids but permeable to gases. Because filter 216 is sized and shaped to fill the inner diameter of conduit 214, liquids that might otherwise flow through conduit 214 (e.g., purge fluid leaking into the central lumen of catheter 210) will be "blocked" by filter 216. Because filter 216 is within conduit 214 (extending between catheter 210 and compartment 200), it effectively blocks liquids from reaching the interior of compartment 200 (which holds electronic components 240) via conduit 214.

[0043] Figure 3 shows a compartment 300 with two side ports, according to certain embodiments. Figure 3 is similar to Figures 1 and 2 above. In relation to Figure 1, pressure side arm 330 corresponds to pressure side arm 130, purge side arm 320 corresponds to purge side arm 120, and catheter 310 corresponds to elongate catheter body 110. In relation to Figure 2, electronic element 340 corresponds to 240, side port 328 corresponds to side port 228, conduit 314 corresponds to conduit 214, and filter 316 corresponds to filter 216. Figure 3 differs from Figure 2 in that Figure 3 includes an additional side port 332. Side port 332 allows for the connection of a pressure side arm 330, such as pressure side arm 130 described above in relation to Figure 1.

[0044] 4A-C illustrate semi-permeable filters according to certain embodiments. FIG. 4A shows semi-permeable filter 416 allowing gas flow, represented by arrow 412, through conduit 410 before any contact with liquid. Gas flow, represented by arrow 412, enters and passes through proximal portion 414 of conduit 410, then passes through filter 416, and then passes through distal portion 418 of conduit 410. FIG. 4B shows filter 416 preventing liquid flow, represented by arrow 422, from passing through conduit 410. Liquid flow, represented by arrow 422, enters distal portion 418 of conduit 410 and encounters resistance at filter 416, preventing the liquid flow from passing through filter 416 to reach proximal portion 414. Instead, the liquid flow exits conduit 410 through distal portion 418. The material properties of the filter 416 cause elements of the filter 416 to swell so that liquid cannot pass the entire length of the filter, preventing liquid flow, represented by arrow 422, from reaching the proximal portion 414 of the conduit 410. FIG. 4C shows the filter 416 allowing gas flow, represented by arrow 412, through the conduit 410 while preventing liquid flow, represented by arrow 422, from passing through the conduit 410. As shown in FIG. 4C, in some embodiments, the filter 416 may simultaneously prevent liquid flow across the conduit 410 while allowing gas flow. In some embodiments, the filter 416 self-seals when exposed to a liquid. In some embodiments, when the filter 416 seals in response to contact with a liquid, the filter 416 also completely or partially seals against gas flow. For example, if the filtration material of the filter 416 swells to prevent liquid flow through the conduit 410, the swelled filtration material may also prevent gas flow through the conduit 410. In some embodiments, the filter 416 is gas permeable but liquid impermeable.

[0045] In some embodiments, the filter 416 may include a hydrogel that can adhere to the pore walls of the porous substrate. The hydrogel may be a hydrophilic polyurethane, a hydrophilic polyurea, a hydrophilic polyureaurethane, or any suitable material. A hydrogel is a material that swells in water and retains a significant percentage of water without dissolving in the water. The porous substrate may be metal, ceramic, glass, organic, inorganic, organic polymer, acrylic polymer, polyolefin, or any suitable material, or combination thereof. The porous substrate from which the filter 416 can be fabricated is insoluble in water and contains one or more channels or pores through which gas or liquid molecules can pass. This allows gas to pass through the channels. The hydrogel adheres to the porous substrate. The hydrogel swells when in contact with liquid, thereby preventing the liquid from passing through the channels. The filter becomes impermeable when in contact with liquid.

[0046] The mechanical, physical, and chemical properties of the filter 416 can be tailored by appropriate selection of the substrate and hydrogel materials, as well as the method used to fabricate the filter material. For example, if rapid self-sealing is desired, small diameter pores or channels may be used. If a smaller pressure gradient across the self-sealing filter is desired, large diameter pores or channels may be used. The hydrogel may be selected to take into account the porosity and composition of the porous substrate. The porous substrate and hydrogel materials may also affect the physical properties of the filter 416 (e.g., strength, flexibility, durability, corrosion resistance, or any other suitable property), and may be selected for the physical properties required in a particular application. For example, the material of the filter 416 may be selected to match the flexibility of the conduit 410. In some embodiments, the material of the filter 416 may be selected to facilitate implementation in a small profile (e.g., within the conduit 410). In some embodiments, the material of the filter 416 may be selected to facilitate formation of a complete seal with the conduit 410 during system manufacture.

[0047] In some embodiments, filter 416 is selectively permeable. Filter 416 may swell and, in some cases, may selectively attract various types of molecules or bonds, thereby sealing off certain substances upon contact with them. For example, filter 416 may attract sugar molecules, thereby blocking the flow of dextrose, while allowing the flow of water or gas (e.g., sterilizing gas). In some embodiments, filter 416 may separate mixtures chromatographically (i.e., by allowing the flow of one component of the mixture through the filter while preventing or at least significantly slowing the flow of another component of the mixture through the filter).

[0048] Figure 5 shows a lumen within compartment 500, according to certain embodiments. Figure 5 is similar to Figure 3 but shows additional details of the tubing within compartment 300, as described below. Compartment 500 corresponds to compartment 300, conduit 520 corresponds to conduit 314, and catheter 510 corresponds to catheter 310. In some embodiments, side joint 502 attaches a pressure side arm (e.g., pressure side arm 330) to compartment 500 through side port 524, and side joint 504 attaches a purge side arm (e.g., purge side arm 320) to compartment 500 through side port 526.

[0049] Compartment 500 may house sensitive electronic devices. PCB 540 holds electronic components (e.g., electronic components 340) within compartment 500. Wires extend from PCB 540 to electronics cable 514. In some embodiments, electronics cable 514 is an insulated cable including at least one wire configured to provide power and electronic signals to a drive system of a pump (e.g., pump 140 of FIG. 1). Electronics cable 514 extends into the proximal end of the central lumen of elongate, multi-lumen catheter 510. In some embodiments, electronics cable 514 extends through the central lumen of catheter 510 to the distal end of catheter 510.

[0050] The system of FIG. 5 includes a series of side joints and lumens connecting with compartment 500, each facilitating direct or indirect connection to catheter 510. A first lumen extends through side joint 504, through side port 526, through a portion of compartment 500, and into the proximal end of the central lumen of catheter 510. A portion of the first lumen is defined by tubing 512. Tube 512 exits compartment 500 through opening 508 and extends through connector 560 (while tubing 512 remains within catheter 510). In some embodiments, tubing 512 extends from the proximal end of catheter 510 to the distal end of catheter 510. For example, as described below in connection with FIG. 1, tubing 512 may terminate in a pump housing (e.g., pump housing 134 of FIG. 1) so that fluid is delivered to a rotor within the pump housing. In some embodiments, the tube 512 terminates in an opening proximal to the distal end of the catheter 510. In some embodiments, the tube 512 extends beyond the distal end of the catheter 510. In some embodiments, the first lumen (defined in part by the tube 512) carries a purge fluid. For example, the first lumen may carry glucose, saline, heparin, or any other suitable fluid.

[0051] The second lumen extends through side joint 502, through side port 524, through a portion of compartment 500, and into the proximal end of the central lumen of catheter 510. A portion of the first lumen is defined by tube 516. Tube 516 exits compartment 500 through opening 508 and extends through connector 560 (while tube 516 remains within catheter 510). In some embodiments, tube 516 extends from the proximal end of catheter 510 to the distal end of catheter 510. For example, as described below in connection with FIG. 1, tube 516 may terminate in a motor housing (e.g., motor housing 102 of FIG. 1) such that fluid is delivered to the motor within the motor housing. In some embodiments, tube 516 terminates in an opening proximal to the distal end of catheter 510. In some embodiments, tube 516 extends beyond the distal end of catheter 510. In some embodiments, the second lumen (defined in part by tube 516) carries a pressure fluid, as described below in connection with Figure 1. For example, the first lumen may carry glucose, saline, heparin, or any other suitable fluid.

[0052] The proximal end of conduit 520 is positioned within compartment 500. Conduit 520 is a hollow tube that extends into and is in fluid communication with the central lumen of catheter 510. A cross-section of the proximal end of catheter 510 shows the central lumen surrounding a first lumen defined by tube 512, a second lumen defined by tube 516, an electronics cable 514, and a third lumen defined by conduit 520. In some embodiments, conduit 520 is significantly shorter than catheter 510. For example, conduit 520 may extend through 1 percent, 2 percent, 5 percent, 10 percent, 20 percent, or any other suitable amount of the length of catheter 510. In some embodiments, conduit 520 allows for the delivery of a gas to the central lumen of catheter 510 configured to sterilize the central lumen. For example, the proximal end of conduit 520 may be exposed to an external source of sterilizing gas, such as ethylene oxide, nitrogen dioxide, ozone, vaporized hydrogen peroxide, or any other suitable gas.

[0053] As shown in enlarged portion 506 of compartment 500, the third lumen defined by conduit 520 holds a filter 528 (e.g., similar to filters 416 and 426 of FIG. 4). In some embodiments, filter 528 is gas permeable and / or self-seals upon contact with liquid. The filter allows sterilizing gas to pass from the proximal end to the distal end of conduit 520. The filter prevents liquid from the central lumen of catheter 510 from reaching the interior of compartment 500 and the electronic components located therein. For example, if tubing 512 or tubing 516 were damaged and purge fluid or pressure fluid were to leak into the central lumen of catheter 510, filter 528 would prevent the leaked liquid from reaching the compartment via conduit 520.

[0054] 6 shows a flow diagram for manufacturing a leak-proof intracardiac blood pump system according to certain embodiments. Method 600 begins with step 602, which involves coating a support substrate with a hydrogel. The hydrogel may be a hydrophilic polyurethane, a hydrophilic polyurea, a hydrophilic polyureaurethane, or any suitable material. The support may be a porous substrate, such as a metal, ceramic, glass, organic, inorganic, organic polymer, acrylic polymer, polyolefin, or any suitable material, or combination thereof.

[0055] Method 600 proceeds to step 604, where the coated filter material is assembled to form a self-sealing filter. In some embodiments, the coated filter material may be assembled into the shape of a thin cylinder. For example, the coated filter material may be assembled to fit snugly within a hollow tube (e.g., conduit 520 in FIG. 5 ). In some embodiments, the coated filter material may be assembled into the shape of a frustum. For example, a filter made from the coated filter material may be stuffed into the end of a hollow tube (e.g., conduit 520 in FIG. 5 ). In some embodiments, the size and shape of the filter are selected to match the size and shape of the hollow tube, as described below. At least one advantage of fitting the filter to the size of the hollow tube is that liquid or gas flowing through the hollow tube will pass through the filter. In some embodiments, the filter may occupy 20 percent, 30 percent, 40 percent, 50 percent, 75 percent, 100 percent, or any other suitable percentage of the length of the hollow tube. In some embodiments, the outer periphery of the cross-section of the filter may be selected to match the inner periphery of the cross-section of the hollow tube. For example, the filter may be effectively packed within the hollow tube to form an aqueous liquid seal between one end of the hollow tube and the other end of the hollow tube. In some embodiments, the cross-section of the filter matches the cross-section of the hollow tube along the entire length of the filter. In some embodiments, the cross-section of the filter may match the cross-section of the hollow tube at a first location and be different from the cross-section of the hollow tube at a second location.

[0056] The method 600 proceeds to step 606, where a self-sealing filter is positioned at the distal end of a sealed compartment (e.g., compartment 100, FIG. 1). The method 600 proceeds to step 608, where an elongate catheter is positioned such that the self-sealing filter extends between the sealed compartment (e.g., compartment 100, FIG. 1) and a portion of the elongate catheter (e.g., elongate catheter body 110, FIG. 1).

[0057] Method 600 proceeds to step 610, which delivers sterilizing gas to the elongated catheter via a hollow tube (e.g., conduit 520 in FIG. 5 ). In some embodiments, the hollow tube is a thin, hollow cylinder having a relatively short length compared to the overall length of the catheter. In some embodiments, the hollow tube is frustum-shaped. Due to the installation of the self-sealing filter (described in steps 606 and 608) and hollow tube, as sterilizing gas flows through the hollow tube, the gas passes from the distal end of the sealed compartment through the filter and into the elongated catheter, allowing fluid communication between the compartment and the catheter. However, the filter, as described in connection with FIGS. 1-5 above, prevents liquid from passing through the hollow tube while allowing gas to pass through the hollow tube.

[0058] Although the steps of method 600 are described in a particular order, these steps may be completed in any order.

[0059] FIG. 7 shows a flow diagram for preventing leakage from a catheter of an intracardiac blood pump, according to certain embodiments. Method 700 begins at step 702, where a conduit is positioned across a first opening of a compartment. The compartment is positioned adjacent to the proximal end of a multi-lumen catheter. In some embodiments, the conduit extends from the interior of the compartment to the central lumen of the catheter. The conduit may have a proximal end and a distal end. For example, the compartment and catheter may be connected with a conduit extending within the compartment and within the catheter between the compartment and the catheter, such that the proximal end of the conduit is within the compartment and the distal end of the conduit is within the catheter.

[0060] Method 700 proceeds to step 704, which involves passing sterilizing gas through the conduit. The sterilizing gas sterilizes the central lumen of the multi-lumen catheter. In some embodiments, the multi-lumen catheter is a main tube having a first diameter and defining a central lumen, with at least one secondary tube running the entire length of the main tube within the central lumen, the secondary tube having a second diameter smaller than the first diameter. The sterilizing gas may be supplied through the conduit to enter the central lumen (defined by the main tube) of the catheter. In some embodiments, the pump is exposed to the sterilizing gas by being placed in a gas-saturated environment. The gas may then pass through the proximal end of the conduit, which may be positioned within the compartment. In this manner, the sterilizing gas is delivered to the interior of the catheter to sterilize the central lumen.

[0061] The method 700 proceeds to step 706 of passing a fluid through the first lumen. The fluid may enter the first lumen from an external source. The first lumen extends through the compartment to the distal end of the multi-lumen catheter. For example, fluid may be passed through the first lumen from an external source to the distal end of the multi-lumen catheter.

[0062] Method 700 proceeds to step 708, where the filter prevents the escape of liquid from the multi-lumen catheter into the compartment while allowing gas to flow from the first end of the conduit to the second end of the conduit. For example, the filter may allow sterilizing gas to reach the central lumen of the catheter, but may prevent any liquid in the central lumen from reaching the compartment after sterilization.

[0063] Although the steps of method 700 are described in a particular order, these steps can be completed in any order. In some embodiments, the gas penetration must occur before the filter comes into contact with the liquid.

[0064] The foregoing is merely illustrative of the principles of the present disclosure, and the device may be practiced in other than the aspects of the present description, which are presented for purposes of illustration and not limitation. It should be understood that while the device disclosed herein has been shown for use in percutaneous insertion of a blood pump, it may also be adapted for use in devices in other applications requiring hemostasis.

[0065] Variations and modifications will occur to those skilled in the art after reviewing this disclosure. The disclosed features may be implemented in any combination and subcombination (including multiple subsidiary combinations and subcombinations) with one or more other features described herein. The various features described or illustrated above, including any components thereof, may be combined or integrated into other systems. Furthermore, certain features may be omitted or not implemented.

[0066] Examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and made a part of this application.

Claims

1. A conduit for use in an intracardiac blood pump system, the blood pump system including a pump, a multi-lumen catheter, at least one internal electronic component, and a compartment connected to the multi-lumen catheter through a first opening, the conduit configured to connect the compartment with the multi-lumen catheter, the conduit comprising: a first end disposed proximal to the first opening; a second end disposed distal to the first opening; and a filter configured to facilitate the flow of gas from the first end to the second end in fluid communication with the multi-lumen catheter while preventing the flow of liquid from the multi-lumen catheter into the compartment; A conduit comprising:

2. 2. The conduit of claim 1, wherein the filter is configured to allow the gas to flow from the first end of the conduit through the second end of the conduit and into the multi-lumen catheter while preventing the liquid from exiting the multi-lumen catheter into the compartment.

3. 2. The conduit of claim 1, wherein the multi-lumen catheter has a first lumen passing through the compartment, and the filter is configured to prevent leakage of liquid from the central lumen of the multi-lumen catheter through the conduit to the compartment.

4. The conduit of claim 1 , wherein the filter is positioned proximal to the first opening of the compartment.

5. The conduit of claim 1 , wherein the filter is positioned distal to the first opening of the compartment.

6. The conduit of claim 1 , wherein the filter extends across the first opening of the compartment.

7. The conduit of claim 1 , wherein a portion of the filter extends into the compartment.

8. The conduit of claim 1 , wherein the liquid comprises at least one of blood, saline, a purge fluid, heparin, and glucose.

9. 4. The conduit of claim 3, wherein the liquid comprises a purge fluid, the purge fluid flowing through the first lumen and into the rotor to maintain the pump substantially free of blood.

10. The conduit of claim 1 , wherein the filter is self-sealing when exposed to a liquid.

11. The conduit of claim 1 , wherein the filter comprises a hydrogel adhered to the pore walls of a porous substrate.

12. 10. The conduit of claim 1, wherein the filter is gas permeable prior to exposure to a liquid.

13. 3. The conduit of claim 1 or 2, wherein the gas is a sterilizing gas.

14. The conduit of claim 3 further comprising a connector at the first opening between the compartment and the multi-lumen catheter, the first lumen and the filter passing through the connector.

15. 15. The conduit of claim 14, wherein the connector has an interior volume and the filter occupies at least 50 percent of the interior volume of the connector.

16. The conduit of claim 1 , wherein the filter is sized and shaped to fit within the conduit.

17. The conduit of claim 1 , wherein the filter is in the shape of a frustum or a thin cylinder.

18. The conduit of claim 3 wherein the first lumen is within the central lumen.

19. The conduit of claim 1 , wherein the at least one internal electronic element comprises at least one of a circuit board, a wire, a soldered or surface mounted electrical connection, a resistor, a capacitor, an inductor, a copper electrical connection, a memory, a pressure transducer, and a pressure sensor.

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