Abstract: A needle-syringe assembly comprises an elongated, generally cylindrical barrel which forms a hollow nozzle located at the distal end of the barrel and which opens into the interior of the barrel. A plunger is slidably mounted in the barrel and forms a longitudinal cavity. A needle holder carries a hollow needle on the distal end, and the needle holder is slidably mounted in the longitudinal cavity of the plunger. The needle holder includes a lateral arm which extends between the plunger cavity and the barrel. A guide means forms a spiral guide surface which extends along a proximal end portion of the barrel for engaging the lateral arm of the needle holder and retracting the needle holder within the barrel in response to relative rotational movement between the barrel and the needle holder.

Abstract: A needle-syringe assembly, operable in a normal mode and convertible to a retraction mode, comprises an elongated, generally cylindrical barrel, a plunger slidably mounted in the barrel, and a needle holder carrying a hollow needle on the distal end thereof. The barrel forms a hollow nozzle located at the distal end of the barrel. The plunger forms a coaxial cavity extending therethrough, and the plunger includes a helical slot exposing a proximal portion of the coaxial cavity. The needle holder is slidably mounted in the coaxial cavity of the plunger. During the normal mode, a distal portion of the needle holder is engaged within the nozzle by a taper lock. To switch from the normal mode to the retraction mode, the taper lock is disengaged by rotary movement of the plunger relative to the barrel.

Abstract: A blood purification system comprised of a dialysis system for purifying a patient's blood and a dual-lumen catheter coupled to the dialysis system. The dual-lumen catheter is comprised of an elongated cylindrical tube having an internal diametral septum extending along the length thereof. The septum and the walls of the elongated cylindrical tube form at least three longitudinal lumens, the first and second of which have substantially semi-circular transverse cross-sections occupying the major portion of the transverse cross section of the interior of the tube, and the third lumen has a small transverse cross-section located at the intersection of one diametral end of the septum with the tube, between a pair of adjacent corners of the first and second lumens.

Abstract: A multiple-lumen intravenous catheter for critical-care applications comprises an elongated cylindrical tube. This tube has a first septum dividing the interior of the catheter into a large lumen having an elliptical cross section, and a smaller lumen having a crescent-shaped cross section. The smallest diameter of the elliptical cross section is larger than the radius of the interior of the catheter. A second septum divides the crescent-shaped lumen into two small lumens.

Abstract: A method of making a multiple-lumen catheter using a co-extrusion die comprises the step of forming an elongated cylindrical tube made of silicone and having an internal septum extending along the length thereof to form at least a pair of longitudinal lumens. While the elongated cylindrical tube is being formed, a nylon reinforcing strip is arranged inside the tube such that the strip extends along the length of the tube. The tube is solidified and cut into individual multiple-lumen catheters. The nylon strip includes a pair of orthogonal side plates which aid in anchoring the nylon strip within the solidified tube.An apparatus for making the multiple-lumen catheter comprises a co-extrusion die, a silicon extruder for injecting silicone into the die, and a pair of rollers for feeding a nylon strip into the die.

Abstract: A needle-syringe assembly, operable in a normal mode and convertible to a retraction mode, comprises an elongated, generally cylindrical barrel, a plunger slidably mounted in the barrel, and a needle holder carrying a hollow needle on the distal end thereof. The barrel forms a hollow nozzle located at the distal end of the barrel. The plunger forms a coaxial cavity extending therethrough, and the plunger includes a helical slot exposing a proximal portion of the coaxial cavity. The needle holder is slidably mounted in the coaxial cavity of the plunger. During the normal mode, a distal portion of the needle holder is engaged within the nozzle by a taper lock. To switch from the normal mode to the retraction mode, the taper lock is disengaged by rotary movement of the plunger relative to the barrel.

Abstract: A dual-lumen catheter comprises an elongated cylindrical tube made of silicone and having an internal septum extending along the length thereof to form a pair of longitudinal lumens. A hollow conical tip is formed on the distal end of the tube with the outside surface of the conical tip merging smoothly with the outside surface of the tube, and the inside surface of the conical tip merging smoothly with the inside surface of one of the lumens.The distal end of the other lumen is longitudinally spaced from the distal end of the tip. A reinforcing member is located inside the tube and extends along the length of the tube. The reinforcing member is made of a material which is substantially stiffer than the material of the tube so that the catheter can be advanced against a resistance by the applications of force to the proximal end of the catheter.

Abstract: A multiple-lumen catheter comprises an elongated cylindrical tube which has an internal diametral septum extending along the length thereof. This septum and the walls of the tube form at least three longitudinal lumens. The first and second lumens have substantially semi-circular transverse cross-sections which occupy the major portion of the transverse cross-section of the interior of the tube. A third lumen has a small transverse cross-section and is located at the intersection of one diametral end of the septum with the tube. This third lumen lies between a pair of adjacent corners of the first and second lumens.

Abstract: A double lumen catheter comprising an elongated cylindrical tube enclosing first and second lumens separated by an internal divider, the proximal end of the elongated tube connecting to two separate connecting tubes communicating with the respective first and second lumens for the injection and removal of blood, the first lumen extending from the proximal end of the elongated tube to a first opening formed in the side wall of the tube and at the distal end of the elongated tube, and the second lumen extending from the proximal end of the elongated tube to a second opening spaced a sufficient distance away from the first opening, in the longitudinal direction, to prevent mixing of the returned blood with the blood taken in, the distal end portion of the tube beyond the distal end of the second lumen continuing the cylindrical configuration of the tube to the distal end of the first lumen so as to form a blunt circular end on the tube to prevent the end of the catheter from traumatizing or becoming caught in th

Abstract: A dual-lumen catheter assembly comprising a dual-lumen catheter, a Y connector having one end fastened to the proximal end of the catheter, and a pair of extension tubes each having one end fastened to the opposite end of the connector from the catheter, each of the extension tubes being bent back toward the distal end of the catheter, extending along opposite sides of the connector.

Abstract: A patient dependent on extracorporeal treatments is subjected to minimal insertion trauma and pain both before and after a fistula operation. A phlebotomy method is disclosed using a veno-occlusive tourniquet or ligation occluding a venous segment at a location between the inlet and return openings of a dual lumen catheter so that a high blood flow rate can be obtained for an extracorporeal treatment system, thereby lessening or delaying the need for a fistula operation. Registration or alignment of the veno-occlusive tourniquet or ligation is ensured by an attachment to the catheter. Preferably the tourniquet or ligation includes an elastic band threaded to the attachment. If a fistula operation becomes necessary or has been performed, insertion trauma and pain is minimized by using a dual-lumen needle having a tapered distal end portion terminating in a beveled cutting edge.

Abstract: A double lumen catheter having an elongated tube with a proximal cylindrical portion enclosing first and second lumens separated by an internal divider, the proximal end of the elongated tube connecting to two separate connecting tubes communicating with the respective first and second lumens for the injection and removal of blood, the first lumen extending from the proximal end of the elongated tube to a first opening at the distal end of the elongated tube, and the second lumen extending from the proximal end of the elongated tube to a second opening spaced a sufficient distance away from the first opening, in the longitudinal direction, to prevent mixing of the returned blood with the blood taken in, the tube having a non-conical and non-tapered distal end portion having a reduced cross-sectional area and extending from said second opening and terminating in a blunt end to prevent the end of the catheter from traumatizing or becoming caught in the walls of a blood vessel into which the catheter is inserted

Abstract: A patient dependent on extracorporeal treatments is subjected to minimal insertion trauma and pain both before and after a fistula operation. A phlebotomy method is disclosed using a veno-occlusive tourniquet or ligation occluding a venous segment at a location between the inlet and return openings of a dual lumen cathter so that a high blood flow rate can be obtained for an extracorporeal treatment system, thereby lessening or delaying the need for a fistula operation. Registration or alignment of the veno-occlusive tourniquet or ligation is ensured by an attachemnt to the catheter. Preferably the tourniquet or ligation includes an elastic band threaded to the attachment. If a fistula operation becomes necessary or has been performed, insertion trauma and pain is minimized by using a dual-lumen needle having a tapered distal end portion terminating in a beveled cutting edge.

Abstract: A double lumen catheter has an elongated tube with a proximal first cylindrical portion having an internal divider to define a pair of discrete lumens including a shorter lumen opening at approximately the distal end of the first cylindrical portion, and a longer lumen opening at the distal end of the elongated tube. To promote insertion and to perform a dilator function, the distal end of the tube has a smooth conical tapered tip that smoothly merges with the distal second cylindrical portion of the elongated tube. Preferably, the lumens are "D" shaped in the first cylindrical portion, a plurality of outlet holes are provided in the vicinity of the conical tapered tip, and the shorter lumen opens at an aperture having a bevel. The double lumen catheter is particularly advantageous when a tunneling procedure or blind technique must be use, for example, to reach a vein under the collar bone or neck.

Abstract: A patient dependent on extracorporeal treatments is subjected to minimal insertion trauma and pain both before and after a fistula operation. A phlebotomy method is disclosed using a veno-occlusive tourniquet or ligation occluding a venous segment at a location between the inlet and return openings of a dual lumen catheter so that a high blood flow rate can be obtained for an extracorporeal treatment system, thereby lessening or delaying the need for a fistula operation. Registration or alignment of the veno-occlusive tourniquet or ligation is ensured by an attachment to the catheter. Preferably the tourniquet or ligation includes an elastic band threaded to the attachment. If a fistula operation becomes necessary or has been performed, insertion trauma and pain is minimized by using a dual-lumen needle having a tapered distal end portion terminating in a beveled cutting edge.

Abstract: A double-current catheter having an elongated cylindrical tube for injection and removal of fluid is provided with a smooth conical tapered tip that smoothly merges with the cylindrical surface of the tube so that insertion trauma and the possibility of kinking are minimized. To provide improved dilator characteristics, preferably the tip includes a relative concentration of material for rigidity, the conical taper is gradual and the apex of the conical tip is substantially centered on the axis of the cylindrical tube. To promote fluid flow, the cylindrical tube preferably includes an internal planar divider defining two "D" shaped lumens. A first lumen extends from the proximal end of the cylindrical tube to a first opening at the distal end, and the second lumen extends from the proximal end to a side opening in the cylindrical surface of the tube. Preferably additional side holes for the lumens are provided to enhance fluid flow.

Abstract: A double lumen catheter has an elongated tube with a proximal first cylindrical portion having an internal divider to define a pair of discrete lumens including a shorter lumen opening at approximately the distal end of the first cylindrical portion, and a longer lumen opening at the distal end of the elongated tube. The longer lumen is further defined by a distal second cylindrical portion of the elongated tube which has a diameter substantially less than the diameter of the first proximal cylindrical portion of the elongated tube. To promote insertion and to perform a dilator function, the distal end of the tube has a smooth conical tapered tip that smoothly merges with the distal second cylindrical portion of the elongated tube. Preferably, the lumens are "D" shaped in the first cylindrical portion, a plurality of outlet holes are provided in the vicinity of the conical tapered tip, and the shorter lumen opens at an aperture having a bevel.

Abstract: A system for dialyzing blood in which blood is passed through an exchange station to transfer toxic material across a semipermeable membrane to a dialyzate. Pump means are disclosed for simultaneously pumping a plurality of liquids through the system at different flow rates. The pump means is provided with mechanism for stopping the flow of dialyzate while retaining the blood pumping capability.

Abstract: A double lumen continuous flow hemodialysis needle and cannula having contiguous lumens of different lengths, the shorter lumen acting as blood intake lumen and the longer as a blood return lumen, each lumen having a beveled edge sloping outwardly and away from the needle which can be inserted percutaneously and which minimizes the possibility of mixing cleansed blood with blood entering the intake lumen.