Abstract: A cochlear implant electrode includes an implantable electrode carrier having an outer surface with electrode contacts for electrically stimulating nerve tissue of the inner ear of a patient. A drug lumen is within the electrode carrier and adapted to receive a therapeutic fluid. The drug lumen contains delivery openings to the outer surface of the electrode carrier and a hydrogel matrix disposed between the drug lumen and the one or more delivery openings and adapted to swell in volume when exposed to the therapeutic fluid. The hydrogel matrix is adapted to control diffusion of the therapeutic fluid from the drug lumen through the delivery openings to the outer surface of the electrode carrier.

Abstract: Devices, systems and methods useable for dilating the ostia of paranasal sinuses and/or other passageways within the ear, nose or throat. A dilation catheter device and system is constructed in a manner that facilitates ease of use by the operator and, in at least some cases, allows the dilation procedure to be performed by a single operator. Additionally, the dilation catheter device and system may be useable in conjunction with an endoscope and/or a fluoroscope to provide for easy manipulation and positioning of the devices and real time visualization of the entire procedure or selected portions thereof. In some embodiments, an optional handle may be used to facilitate grasping or supporting a device of the present invention as well as another device (e.g., an endoscope) with a single hand.

Abstract: The present invention provides a method for treating brain injury or stroke in a subject in need thereof, comprising implanting a microdialysis probe into the injury or insult core of the subject and perfusing the probe with an oncotic agent dissolved in a physiologically acceptable buffer, wherein the microdialysis probe comprises a dialysis membrane with a molecular weight cutoff less than the molecular weight of the oncotic agent.

Abstract: The invention relates to a method and device for dialysis and or bulk fluid removal by generating a fibrosis chamber within a body cavity and performing dialysis or bulk fluid removal. An implantable medical device is described having a fibrosis chamber and a pump. A dialysis chamber and an optional electrodialysis unit can further be provided. An additional controller uses sensory feedback to regulate the fluid levels by altering the extracellular fluid retention within the fibrosis chamber. This device can be used for the treatment of patients with chronic kidney disease who may also be suffering from cardiorenal syndrome and hypertension.

Abstract: In a gas supply system, a controller is electrically connected to a pressure regulator and an operation switch. The controller is operative to control the pressure regulator so that a predetermined gas is supplied to a first delivery member directing to a first body cavity with its pressure regulated to a first pressure suitable for the first body cavity. The controller is operative to control the pressure regulator depending on an instruction sent from the operation switch upon operation of the operator so that the predetermined gas is supplied to a second delivery member directing to a second body cavity with its pressure regulated to a second pressure suitable for the second body cavity.

Abstract: A cleaning catheter (200) includes fluid-delivery and suction lumens (520, 530). A flow regulator (700) defines suction and fluid ports (830, 827). A mechanical user control element (320) is configured to mechanically and non-electrically set activation states of the flow regulator (700), and transition between first and third configurations via a second configuration. When the control element (320) is in the first configuration, the flow regulator (700) blocks fluid communication (a) between the suction port (830) and the suction lumen (530) and (b) between the fluid port (827) and the fluid-delivery lumen (520). When the control element (320) is in the second configuration, the flow regulator effects fluid communication between the suction port (830) and the suction lumen (530), and blocks fluid communication between the fluid port (827) and the fluid-delivery lumen (520).

Abstract: An irrigation and suction tip for laparoscopic surgery having an increased range of transport within a surgical cavity during laparoscopic surgery. The tip moves in a circumferential trajectory rather than linearly when a surgeon is irrigating and suctioning tissue. The tip is substantially resilient, withstanding great force and pressure during irrigation and suction procedures. The tip is bowed, having a pair of straight portions, a short distal portion and a long proximal portion joined by a bowed portion, the bowed portion allowing the distal portion to rotate, circumscribing a large area. The bow is limited so that the tip moves within a narrow wall of a cannula of a trocar.

Abstract: A device for the laser transmission welding of two plastic assembly parts is provided, wherein at least one of the plastic assembly parts contains an absorber for laser light, comprising a processing head with a processing side, with a processing-side discharge shaft for at least one laser beam and with a laser-transparent pressing means for pressing together the plastic assembly parts, wherein the laser-transparent pressing means is guided decoupled from the processing head in the discharge shaft. Furthermore, a method for producing a welded joint between two plastic assembly parts by laser transmission welding is specified.

Abstract: Systems and methods for fluid control during aspiration. In an embodiment, an aspiration system includes an aspiration line having distal and proximal ends and an aspiration port defined in the distal end; a fluid transport device operatively coupled to the proximal end of the aspiration line; and a flow restrictor operatively coupled to the aspiration line in between the fluid transport device and the aspiration port. To measure occlusion within the line, first and second pressure sensors are utilized, the first sensor being operatively coupled to the aspiration line between the port and the restrictor and the second sensor being operatively coupled to the aspiration line between the restrictor and the fluid transport device. The pressure differential between the two sensors can provide an indication of the onset, presence, and/or elimination of an occlusion.

Abstract: Under one aspect of the present invention, a catheter includes an elongate member; a plurality of septa configured to define a plurality of lumens along the elongate member; and a plurality of slits defined through the elongate member, each slit configured to provide fluidic communication between an environment about the catheter and a corresponding lumen of the plurality of lumens, at least one slit having a different length than at least one other slit.

Abstract: A method for delivering a fluid to an animal with a drug delivery device without causing contamination to the drug delivery device. The drug delivery device used by the method may comprise a fluid subsystem with a switching device, disposable syringes, fluid reservoirs, disposable tubing, and a catheter. In one embodiment, the method allows a user to deliver multiple drugs to an animal without contaminating the valves that control the flow of fluid.

Abstract: A medical treatment system, such as peritoneal dialysis system, may include control and other features to enhance patient comfort and ease of use. For example, a peritoneal dialysis system may include patient line state detector for detecting whether a patient line is primed before it is to be connected to the patient. The patient line state detector can also the ability to detect whether a patient line has been properly mounted for priming. Both patient line presence/absence and fill state can be determined using an optical system, e.g., one that employs a single optical sensor.

Abstract: A surgical system comprises a pressurized irrigation fluid source; an irrigation line fluidly coupled to the pressurized irrigation fluid source; a hand piece fluidly coupled to the irrigation line; an irrigation pressure sensor located at or along the pressurized irrigation fluid source or irrigation line; and a controller for controlling the pressurized irrigation fluid source. The controller controls the pressurized irrigation fluid source based on a reading from the irrigation pressure sensor and an estimated flow value modified by a compensation factor.

Abstract: Methods and apparatus for supplying fluid during a tissue coagulation procedure.

Abstract: A device for removing secretions from an artificial tube is provided. The device may include a clearing catheter and a driving mechanism that may apply repetitive motion to the clearing catheter. In another version of the device, the clearing catheter may dispense irrigation fluid and aspirate the irrigation fluid. The clearing catheter may have an irrigation and an aspiration lumen that may both reciprocate with the clearing catheter. In another version a compliant member into which irrigation fluid is located may be present.

Abstract: An apparatus includes a cannula assembly, a housing, a fluid reservoir, a flow control mechanism, and an actuator. The housing includes an inlet port removably coupled to the cannula assembly and defines an inner volume. The fluid reservoir is fluidically coupled to the housing and configured to receive and isolate a volume of bodily fluid from a patient. The flow control mechanism is at least partially disposed in the inner volume. The actuator is operably coupled to the flow control mechanism and is configured to move the flow control mechanism between a first configuration, in which bodily fluid can flow, via a fluid flow path defined by the flow control mechanism, from the cannula assembly, through the inlet port and into the fluid reservoir, to a second configuration, in which the fluid reservoir is fluidically isolated from the cannula assembly.

Abstract: A bioartificial kidney equivalent and a process for producing the bioartificial kidney equivalent. The hybrid bioartificial kidney comprises human proximal and distal renal tubule cells grown on particular synthetic membranes.

Abstract: An apparatus for transferring an ovum from a follicle with a double lumen needle having at the distal needle end an aspiration lumen for removing an ovum from a follicle and a flushing lumen, the double lumen needle including an outer tube with an internally located inner tube that extends over at least part of the length of the outer tube, one of the lumens being bounded by the inner surface of the inner tube and the other of the two lumens by the space between the outer surface of the inner tube and the inner surface of the outer tube, and a connector having an outlet at a second connector end for discharging the flushing fluid with possibly an ovum to the exterior and having a channel that connects the outlet with the aspiration lumen and a flushing inlet for supplying the flushing fluid, such that the two fluid pathways within the connector and the double lumen needle are separated from each other, and the inner tube comprises a deformable material.

Abstract: A dialysis machine includes: a hardware unit including at least one pump actuator, at least one valve actuator and a cassette interface, the cassette interface including: (i) a plate that abuts the cassette; (ii) at least one pump aperture defined by the plate; (iii) at least one pump head moveable out of and retractable into the at least one pump aperture to operate a pumping portion of the cassette; (iv) at least one valve aperture defined by the plate; (v) at least one valve apparatus moveable out of and retractable into the at least one valve aperture to operate a valve portion of the cassette; (vi) at least one sensor aperture defined by the plate; and (vii) at least one sensor located in the least one sensor aperture, the at least one sensor operable with a sensor portion of the cassette.

Abstract: A dialysis machine includes: a hardware unit including at least one pump actuator, at least one valve actuator and a cassette interface, the cassette interface including: (i) a plate that abuts the cassette; (ii) at least one pump aperture defined by the plate; (iii) at least one pump head moveable out of and retractable into the at least one pump aperture to operate a pumping portion of the cassette; (iv) at least one valve aperture defined by the plate; (v) at least one valve apparatus moveable out of and retractable into the at least one valve aperture to operate a valve portion of the cassette; (vi) at least one sensor aperture defined by the plate; and (vii) at least one sensor located in the least one sensor aperture, the at least one sensor operable with a sensor portion of the cassette.

Abstract: A separation system for separating a multiple component material into at least two fractions. The separation system includes a separation device having a first end, a second end opposite to the first end, and a sidewall that extends between the first end and the second end to define a separation chamber having an interior volume. The system also includes a valve moveable between an open position and a closed position, the valve is mounted at a fixed location within the separation chamber at a position that is closer to the second end than to the first end and is spaced apart from the second end, the valve is operable to isolate a first fraction of the multiple component material having a first density on a first side of the valve from a second fraction having a second density on a second side of the valve that is opposite to the first side.

Abstract: A cannula having a proximal end, a distal end, and a lumen extending between the proximal and distal ends is provided. The diameter of the lumen of the cannula can be varied to take into account differences in the diameter of access and target vessels during cannulation. The cannula is further characterized by at least one mechanism that, upon actuation, serves to alter the conformation of the cannula between a normal profile conformation and a low profile conformation. The normal profile conformation is characterized by the cannula having a lumen diameter at the point of insertion, which is smaller than the lumen diameter both proximal and distal to the point of insertion, with the lumen diameter distal to the point of insertion also expandable to the diameter of the cannulated vessel of the patient. The low profile conformation is characterized by the cannula having a lumen diameter at the point of insertion that is greater than the lumen diameter distal to the point of insertion.

Abstract: The invention provides an improved microdialysis method for determining the free concentration of an agent or drug (defined as the concentration of agent that is dissolved and free to diffuse, and not undissolved or precipitated, complexed, bound, included in micelles or microemulsions, etc.). In addition. the invention provides such a method under conditions in which the properties of the microdialysis probe may change. Further, the invention provides a method for determining the permeability of a diffusible agent through the probe wall. The invention also provides a method for determining the rate of change of concentration of an agent in a medium.

Abstract: In a method for the automatic control of blood pumps, an optimization of the blood flow is achieved by periodic speed interventions and flow changes thereby occurring, using a formed differential variable and a control algorithm. In addition, the location of possible flow resistances on the venous or arterial side can be ascertained.

Abstract: The present disclosure relates in general to an apparatus and method for priming a liquid or surgical cassette. In one embodiment, an infusion system within the liquid cassette is primed using a forward flow of a liquid and a backward flow of the liquid. The forward flow of the liquid creates a first volume of liquid stored within an infusion conduit, which is connected to an infusion chamber via a first valve. The infusion conduit has an infusion port exposed to a non-liquid environment having a first pressure. A second pressure is created in the infusion chamber that is lower than the first pressure. Opening the first valve causes a second volume of liquid within the infusion conduit to flow over the first valve and towards the infusion chamber. The second volume of liquid is less than or equal to the first volume of liquid.

Abstract: A method of performing peritoneal dialysis includes: (i) locating a supply of fresh dialysis fluid above a patient's peritoneal cavity; (ii) locating a drain or a drain container below the patient's peritoneal cavity; (iii) connecting a supply line to the supply of fresh dialysis fluid and the patient's peritoneal cavity; (iv) connecting a drain line to the patient's peritoneal cavity and the drain or drain container; (v) pneumatically opening a supply line valve during a fill cycle; (vi) gravity filling the patient's peritoneal cavity with the supply line valve open during the fill cycle; (vii) pneumatically opening a drain line valve during a drain cycle; and (viii) draining the patient's peritoneal cavity with the drain line valve open during the drain cycle.

Abstract: An artificial liver system for treating liver failure includes a reservoir to provide albumin-containing dialysis fluid to the patient's peritoneum, an implantable device including a pump to pump the fluid from the peritoneum to the bladder via respective catheters, control circuitry, battery and transceiver; a charging and communication system configured to periodically charge the battery and communicate with the implantable device to retrieve data reflective of the patient's health; and monitoring and control software, suitable for use with conventional personal computers, for configuring and controlling operation of the implantable device and charging and communication system. The monitoring and control software allows a treating physician to remotely adjust the volume, time, and frequency with which fluid is pumped from the peritoneal cavity to the bladder based on the data reflective of the patient's health.

Abstract: Disclosed herein are various device embodiments providing for single-handed operation of dual fluid injection or fluid injection/aspiration. The inventions further contemplate methods of using the devices using real-time imaging technologies. The single-handed device has structures for selectively applying two or more sources of positive or negative pressure through an attachable needle for said dual fluid injections or aspiration.

Abstract: Very accurate measurements of mass transfer can be made rapidly by permitting diffusion of an agent desired to be measured into or out of a small, very precisely known volume of a microdialysis probe, then rapidly pumping or flushing (“pulsing”) the probe with a known volume of fluid as a single pulse. The diffusion and pulsing may be repeated. The method, hereinafter called pulsatile microdialysis (PMD) to distinguish it from prior art continuous flow microdialysis, is useful for measurements in a number of processes, including protein binding, adsorption to binding agents such as activated charcoal, release from microemulsion drug delivery systems, determination of drug diffusion coefficients and concentrations, and for various other purposes. The method is based on mathematical manipulation of Fick's Laws. Resulting equations were verified against experimental data using methazolamide, warfarin and benzocaine as test drugs.

Abstract: Very accurate measurements of mass transfer can be made rapidly by permitting diffusion of an agent desired to be measured into or out of a small, very precisely known volume of a microdialysis probe, then rapidly pumping or flushing (“pulsing”) the probe with a known volume of fluid as a single pulse. The diffusion and pulsing may be repeated. The method, hereinafter called pulsatile microdialysis (PMD) to distinguish it from prior art continuous flow microdialysis, is useful for measurements in a number of processes, including protein binding, adsorption to binding agents such as activated charcoal, release from microemulsion drug delivery systems, determination of drug diffusion coefficients and concentrations, and for various other purposes. The method is based on mathematical manipulation of Fick's Laws. Resulting equations were verified against experimental data using methazolamide, warfarin and benzocaine as test drugs.

Abstract: The disclosed devices and methods provide for the minimization of fluid extravasation during use of infusion catheters such as peripherally inserted central catheters and central venous catheters. The anti-extravasation catheter allows a surgeon to drain fluids from soft tissue surrounding an infusion site while also providing fluid inflow to a patient.

Abstract: Very accurate measurements of mass transfer can be made rapidly by permitting diffusion of an agent desired to be measured into or out of a small, very precisely known volume of a microdialysis probe, then rapidly pumping or flushing (“pulsing”) the probe with a known volume of fluid as a single pulse. The diffusion and pulsing may be repeated. The method, hereinafter called pulsatile microdialysis (PMD) to distinguish it from prior art continuous flow microdialysis, is useful for measurements in a number of processes, including protein binding, adsorption to binding agents such as activated charcoal, release from microemulsion drug delivery systems, determination of drug diffusion coefficients and concentrations, and for various other purposes. The method is based on mathematical manipulation of Fick's Laws. Resulting equations were verified against experimental data using methazolamide, warfarin and benzocaine as test drugs.

Abstract: The present invention provides a catheter for use in delivering and/or recovering materials to and/or from a tissue site in the body, the catheter comprising one or more macroporous regions adapted to selectively deliver molecules and/or recover cells from the tissue site, based on one or more physical-chemical-biological characteristics. The macroporous region can be provided in the form of a helical hollow wires, and can be adapted to both recover cells from the tissue site (e.g., bacterial or other cells present in interstitial fluid) and optionally to permit the infusion of medicament to the site, under corresponding conditions.

Abstract: A medical blood access system used for hemodialysis treatment to enable blood withdrawal for processing of blood by an external apparatus and return the same blood to a patient, comprising an interfacial fluid conduit between the machine and patient's blood supply which is repeatedly connectable along a guided pathway passing through epidermis and subcutaneous tissue via a naturally formed tissue tract to enter blood space, providing improved patient safely, convenience, effective prophylaxis, without bleeding or tissue trauma or pain, and is executable by the patient to precisely connect and disconnect with minimal disfigurement or life restrictions, and is useable on virtually all patients soon after placement and is robust and safe to high blood flow.

Abstract: A method for the control of valves for flow path control, in particular in a medical treatment machine, having a plurality of processes for the manufacture of flow paths by control of a group of valves, with each process claiming a group of valves suitable for its carrying out for itself so that other processes cannot change the switching state of these valves and with each process itself making a decision on the release of the valves claimed by it. In addition, a method is provided for monitoring the then current and/or scheduled state of a plurality of valves in the flow path control, determining the connections resulting from the switching state of the valves, and comparing the resulting connections with a predetermined number of non-permitted connections.

Abstract: A system is for thermal ablation and includes (a) a heating element heating an ablation fluid flowing through an ablation device and to a target region of a body and (b) a computing arrangement controlling power supplied to the heating element supplying power to heat the ablation fluid to a desired temperature. The computing arrangement reduces the supplied power when a detected ablation fluid temperature exceeds a desired temperature and increases the supplied power when the detected ablation fluid temperature is below the desired temperature. The computing arrangement monitors a percentage of heat supplied by the heating arrangement to heat the fluid to the desired temperature as a function of a maximum amount of heat which the heating element is capable of supplying.

Abstract: An automated peritoneal dialysis system provides various features including prescription-driven dialysis fluid preparation, an integrated disposable fluid circuit, and sensor capabilities that allow accurate filing and draining control with high safety margins. Features include a peritoneal fluid circuit with a pressure sensor at either end and methods and devices for using the pressure signals. Other features and embodiments are disclosed.

Abstract: A device for treatment of a blood vessel includes: a catheter (C) configured to be inserted in a blood vessel (V) to be treated; a selection member (S) associated with the catheter (C) to prevent a blood flow at least in a determined section (T) of the blood vessel (V); a self-perfusion lumen associated with the catheter (C) to provide a fluidic connection between a first portion (P1) of the blood vessel (V) upstream the determined section (T) and a second portion (P2) of the blood vessel (V) downstream the determined section (T); a treatment system (F) associated with the catheter (C) to make a fluid drug flow at least to the determined section (T).

Abstract: An earplug insertion device can include a housing that is configured to hold a first earplug and a second earplug. The device can also include an ejection mechanism that can be configured to respond to a first user force by ejecting the first earplug from the device in a first ejection motion. The ejection mechanism can also being configured to respond to a second user force by ejecting the second earplug from the device in a second ejection motion.

Abstract: Disclosed are devices, methods and systems for treatment of eye disease such as glaucoma. Implants are described herein that enhance aqueous flow through the normal outflow system of the eye with minimal to no complications. The implant can be reversibly deformed to a first shape, such as a generally linear shape conducive to insertion. Upon insertion, the implant can deform to a second shape, such as a generally non-linear shape conducive to retention within the eye. The shape also improves fluid flow from the anterior chamber and prevents or reduces clogging.

Abstract: A dialysis system includes a source of effluent dialysis fluid, a drain container configured to receive the effluent dialysis fluid through a drain tube, and a load cell. The drain container includes an at least semi-rigid body defining a first key feature. The load cell includes a second, mating key feature positioned and arranged to mate with the first key feature.

Abstract: A method for a hybrid blood and peritoneal dialysis (“PD”) machine comprising: (i) determining whether a previous treatment left a last fill of dialysate in a patient's peritoneum; (ii) if a next treatment is a PD treatment, and if the previous treatment did not leave the last fill of dialysate, causing a PD treatment in which a first cycle is a fill cycle to be initiated; (iii) if the next treatment is a PD treatment, and if the previous treatment did leave the last fill of dialysate, causing a PD treatment in which a first cycle is a last fill drain cycle to be initiated; and (iv) if the next treatment is a blood treatment and if the previous treatment did leave the last fill of dialysate, causing a blood treatment including a last fill drain cycle to be initiated.

Abstract: A neonatal feeding tube (10) includes electronics and instrumentation for monitoring a neonate and for provides nourishment to the neonate. The tube (10) includes electrodes (20) for sensing ECG signals of the neonate. Thermistors (22, 24, 28, 30) are placed at various points along the tube (10) to measure the neonate's temperature at those points. Breathing effort is measured by calculating a pressure differential at two pressure ports (32, 34). Pulse and SpO2 are measured at a fiber optic window (35). The electrodes (20), a distal electrode (64) and a light source (66) aid in helping a caregiver position the tip (12) of the tube (10) correctly in the stomach of the neonate.

Abstract: The present invention provides an oral medicinal composition for peritoneal dialysis patients to suppress an increase of carbonyl compounds and/or advanced glycation/lipoxidation end products (AGEs) in the peritoneal cavity and peritoneal tissue after intraperitoneal administration of a glucose-containing peritoneal dialysis fluid, the oral medicinal composition comprising a pharmaceutically acceptable salt of pyridoxamine as an active ingredient.

Abstract: This disclosure relates to medical fluid cassettes and related systems and methods. In certain aspects, a medical fluid cassette includes a base having a first region and a second region, a first membrane overlying the first region of the base, and a second membrane overlying the second region of the base. The second membrane is configured to rebound away from the base when a force used to press the second membrane toward the base is released.

Abstract: A peritoneal dialysis machine including a membrane pump and a touch screen display that includes a mode-indicating portion and an operation-descriptive portion, the mode-indicating portion having a plurality of touch sensitive indicia each indicating one of a plurality of modes in which the machine can operate, the display being used to keep a patient continually informed of which one mode of at least three operating modes the machine is operating in, as the operation-descriptive portion changes to display details of a specific operation being carried out within the one mode, the indicia for each of the three operating modes always being visible to the patient while the machine is operating, the operating mode being selected by the patient touching one of the indicia on the screen.

Abstract: A peritoneal dialysis system includes: an enclosure including an actuation surface and a door; a stepper motor housed by the enclosure; a pump head and a solid pump piston structurally linking the pump head to the stepper motor; and a disposable unit accepted by the enclosure, the disposable unit including a flexible membrane attached to a rigid piece, the actuation surface of the enclosure and the disposable unit so configured and arranged that when the stepper motor turns and consequently translates the solid pump piston and the pump head towards the door, the pump head physically contacts and stretches the membrane from a relaxed position to a stretched position, and when the stepper motor turns and consequently translates the solid pump piston and the pump head away from the door, the membrane follows the pump head and transitions from the stretched position to the relaxed position.

Abstract: Surgical fluid management systems and methods of operating surgical fluid management systems which may provide one or more functions associated with suction, irrigation, distention, deficit monitoring, infusion, fluid warming, and the like. Some example embodiments may include infra-red lamps arranged to heat fluid flowing through a disposable cartridge. Some example embodiments may provide a three-dimensional fluid path through the cartridge and/or multi-stage heating capabilities. Some example fluid management systems may be selectable between pressure control and flow control modes.

Abstract: An embodiment of the invention includes a quantum fluid flow management apparatus which controls and facilitates delivery of liquid and/or air to the surgical site during a surgical procedure via a trumpet valve, various restriction (crimping) devices, and a network of tubing for selectively passing air or fluid through to the surgical site. The trumpet valve allows for selective control of air or fluid or both or neither. Additionally the flow management apparatus controls the application and suction of fluids from the surgical site which may be used in cooperation with the injection of a fluid such as water to irrigate the surgical site to remove body fluids, debrided material or the like.

Abstract: A dialysis catheter including a first portion having an outer wall having a first diameter, an elongated distal portion having a second diameter smaller than the first diameter, and a transition region between the first portion and distal portion. A first longitudinally extending venous lumen is configured to deliver blood. First and second independent longitudinally extending arterial lumens are configured to withdraw blood from a patient. The venous lumen and arterial lumen have first and second regions each positioned a first distance from the outer wall of the catheter and a third region positioned a second shorter distance from the outer wall of the catheter to form an arch shaped wall portion progressively increasing in thickness from the third region toward the first region and from the third region to the second region.