Abstract: A differential conductivity recirculation monitor quantitatively determines the degree of recirculation in a fistula by comparing the conductivity of blood entering the fistula to the conductivity of blood being withdrawn from the fistula. A discrete quantity of a high conductivity marker fluid is injected into the blood entering the fistula, altering the conductivity of the blood entering the fistula. The altered conductivity blood enters the fistula and, if recirculation is present, co-mingles with blood in the fistula, altering the conductivity of the blood ion the fistula in proportion to the degree of recirculation. Blood withdrawn from the fistula has an altered conductivity related to the degree of recirculation. Quantitative values of the conductivity of the altered conductivity blood entering the fistula and the conductivity of the blood being withdrawn from the fistula are measured and a difference determined.

Abstract: A differential conductivity recirculation monitor quantitatively determines the degree of recirculation in a fistula by comparing the conductivity of blood entering the fistula to the conductivity of blood being withdrawn from the fistula. A discrete quantity of a high conductivity marker fluid is injected into the blood entering the fistula, altering the conductivity of the blood entering the fistula. The altered conductivity blood enters the fistula and, if recirculation is present, co-mingles with blood in the fistula, altering the conductivity of the blood ion the fistula in proportion to the degree of recirculation. Blood withdrawn from the fistula has an altered conductivity related to the degree of recirculation. Quantitative values of the conductivity of the altered conductivity blood entering the fistula and the conductivity of the blood being withdrawn from the fistula are measured and a difference determined.

Abstract: A plasma sequestration system having a volume control system is provided. When a calculated volume of whole blood has been processed, the system switches from a fill to an empty cycle. The termination point is calculated in advance, based on the desired composition of the collected plasma, thus improving process control and product uniformity. The system is automated or partially automated using an optical sensor or marker to monitor the volume of packed red blood cells. When the red cells reach the marker or sensor, a signal is sent to the control system which then calculates the required fill volume. Processing continues until the calculated fill volume is reached, at which time the system automatically stops the collection cycle. The system also provides for two speed operation of the centrifuge as a safeguard against foaming which may result in aerosol formation and blood trauma.

Abstract: An apparatus for trapping bubbles in blood flowing in a circuit, such as blood in an extracorporeal circuit, is provided. The apparatus includes a housing which defines a substantially vertical chamber. Blood is introduced into the chamber through an inlet tube extending downwardly into the chamber and is removed from the chamber at an exit port near the lower end of the housing. A diverter having a container base and rim is positioned within the chamber. Blood is introduced near the container base. The blood is redirected upward upon contact with the container base and is then redirected downward over the rim. The redirection of blood flow provides an opportunity for bubbles in the blood to separate from the blood in the chamber and also helps prevent stagnation of blood in the chamber which might otherwise lead to clotting and separation of the blood. Blood is introduced into a chamber of the apparatus in a generally downward direction below the level of blood already present in the chamber.

Abstract: A method and device for sampling biological fluids during collection without opening the functionally closed collection system, thereby compromising the sterility of the collected fluid. A sample bag connected to a fluid line or collection reservoir is filled coincident with fluid collection, then hermetically sealed and physically separated from the collection system using a radio frequency tubing sealer. A vacuum tube collection device is attached to the sample bag to minimize exposure to the fluid during sample handling and processing.

Abstract: A blood component collection system with optimization capabilities. In one embodiment, process parameters are derived from an input/configured predetermined blood component yield and which is based upon the maximization of at least one process parameter. Thereafter, the blood component collection procedure is performed with these derived process control parameters. In another embodiment, process parameters are derived from an input total procedure time from a maximized value for at least one of the other process control parameters so as to maximize blood component yield in this fixed time. Thereafter, the blood component collection procedure is performed with these derived parameters.

Abstract: An exchanger includes an outer casing having an inlet port and an outlet-port for a first fluid, and an inlet port and an outlet port for a second fluid, and a bundle of hollow fibers located within the outer casing and being in flow communication with the inlet and outlet port for the second fluid. A central core is located in the outer casing and the bundle of fibers is arranged around the central core. The central core includes an inlet manifold connected to the first fluid inlet port, and an outlet manifold connected to the first fluid outlet port.

Abstract: A method of therapeutic or diagnostic treatment using a medical agent in which there will be beneficial effects if the level of circulating medical agent is reduced artificially faster than the reduction by the normal clearance or routes that obviate normal clearance mechanisms. The method includes the extracorporeal removal of the medical agent by passing bodily fluid from the patient over a support adapted to selectively immobilize the medical agent.

Abstract: An exchanger for oxygenating blood includes a casing having walls and a cavity, sheet material with first and second ends covering distal edges of the walls, and a cover extending over the cavity to sandwich the first and second ends of the sheet material between the cover and the edges of the walls. The cover is melted into the sheet material and the distal edges of the walls. In another embodiment, a blood oxygenator includes a first compartment having a closed casing divided by a folded sheet of membrane material forming a first blood chamber and a first gas chamber. The casing has first and second manifolds in fluid communication with the first blood chamber. A second compartment is interconnected with the first compartment and has a closed casing divided by a folded sheet of membrane material forming a second blood chamber and a second gas chamber. The casing has third and fourth spaced apart manifolds in fluid communication with the second blood chamber.

Abstract: A method for manufacturing an exchanger includes the steps of folding sheet material in a series of pleats, placing the folded sheet material in a casing having an opening defined by walls with distal edges, covering the distal edges with end portions of the sheet material, and affixing a cover to the casing by simultaneously melting a portion of the cover and the sheet covered distal edges of the walls, and contacting the cover with the sheet material covering the distal edges of the walls. The method may also include melting a portion of the cover and/or the casing and placing the melted cover on the casing so that the melted portion contacts pleats of the sheet material, and permitting the melted material to cool and solidify and form a bond with the sheet material.

Abstract: A medical system for transferring fluids (e.g. blood) to or from patients which includes a needle having a proximal end, a distal end attached to a syringe (or other comparable fluid transfer device), a medial section, and an internal passageway. The medial section is elliptical in cross-section with dual arcuate side walls. The proximal end is blunt and rounded. Also included is an access site having a conduit with a resilient tubular port extending outwardly therefrom. The port includes a bore therethrough. The port and the bore are both elliptical in cross-section. A resilient compression member having an elliptical opening therein is positioned on the port to exert pressure thereon and close the bore. In use, the needle is urged into the bore, temporarily deforming the compression member. After removing or delivering fluids using the syringe (or other device), the needle is withdrawn from the bore which is self-sealing by the compressive action of the compression member.

Abstract: A method and apparatus to concentrate and purify islets of Langerhans from a tissue suspension containing islets and tissue fragments. The tissue suspension is flowed through an inclined channel such that laminar flow is established in the channel. The islets settle toward the channel bottom and are drawn out of the channel through an outlet in the channel bottom, while the remaining tissue suspension flows out a second outlet positioned higher than the islet outlet. Additional concentration or purification may be accomplished by passing the islets through the channel additional times and by centrifuging or filtering operations.

Abstract: An integrated blood treatment fluid module is provided having particular multi-function application in the treatment of renal failure. The module comprises a support member, a blood treatment device mounted to the support member, and multiple fluid circuits, wherein a plurality of the fluid circuits are interconnected to the support member and at least one of the fluid circuits is fluidly connected to the blood treatment device. At least two of the fluid circuits are interconnected with the support member so as to have a portion of each disposed in a U-shape, each U-shape portion extending in a different direction, for selective positioning about a corresponding peristaltic pump of a blood treatment apparatus. For renal treatment applications, the blood conditioning device may be a hemofiltration device, hemodialysis device or high-flux dialyzer.

Abstract: A single needle system for withdrawing donated blood, processing the blood to harvest components such as platelets, and returning processed blood to the donor through the single needle. Processing is performed by a centrifuge which separates blood components into stratified layers with a buffy coat containing platelets and white blood cells stably interfacing a red blood cell layer. Blood is withdrawn during a draw cycle and returned to the donor during a return cycle. A recirculation system is provided so that blood flows at a reduced rate through the processing system during the return cycle in order to minimize return cycle time while maintaining the stable position of the interface between buffy coat and red blood cell layers. A storage bag receives processed blood during the draw cycle and blood is squeezed from the bag during the return cycle, a portion returned to the donor and another portion entering the recirculation path.

Abstract: A plasma sequestration system having a volume control system is provided. When a calculated volume of whole blood has been processed, the system switches from a fill to an empty cycle. The termination point is calculated in advance, based on the desired composition of the collected plasma, thus improving process control and product uniformity. The system is automated or partially automated using an optical sensor or marker to monitor the volume of packed red blood cells. When the red cells reach the marker or sensor, a signal is sent to the control system which then calculates the required fill volume. Processing continues until the calculated fill volume is reached, at which time the system automatically stops the collection cycle. The system also provides for two speed operation of the centrifuge as a safeguard against foaming which may result in aerosol formation and blood trauma.

Abstract: A method and apparatus for determining, controlling or establishing the level of a constituent such as anticoagulant in a body fluid such as blood in a procedure for processing the fluid. The anticoagulant flow rate from an anticoagulant reservoir, the blood flow rate, the flow rate of collected fluid and the flow rate of replacement fluid are monitored, and an anticoagulant flow balance is established whereby the flow of anticoagulant into the donor or patient will be equal to the flow rate of anticoagulant out of the anticoagulant reservoir, plus the flow rate of anticoagulant from the donor or patient, plus the flow rate of anticoagulant in the replacement fluid, minus the flow rate of anticoagulant in the collect fluid. The flow rate of anticoagulant from the donor or patient can be determined based on the anticoagulant metabolic half-life, the volume of the donor's or patient's blood, and the amount and time of infusion of anticoagulant into the donor or patient.

Abstract: A method and apparatus for cleaning of a dialysate circuit located downstream of the dialyzer in a dialysis machine is described. The method comprises injecting a cleaning agent into the dialysis machine at a point between the dialyzer inlet port and the downstream dialysate circuit in an amount sufficient to substantially reduce the deposit in said downstream dialysate circuit; permitting flow of the agent towards the downstream dialysate circuit; and substantially preventing flow of the agent toward the dialyzer inlet port. The injection adaptor apparatus comprises an injection connector downstream of a backflow prevention valve, and two flanking tubing connectors. The apparatus is inserted at a point downstream of the dialyzer inlet port, and cleaning agent is injected into the injection connector. An adaptor to facilitate handling of cleaning agent during manual agent injection is also described. Additionally, an automated agent injection apparatus is described.

Abstract: Inclusions in a liquid flow, such as air bubbles in a blood flow, are detected by transmitting a signal through the fluid and receiving and interpreting the received signal based on the expected degree of attenuation for the liquid and the inclusions. The amplitude of the transmitted signal is automatically adjusted to maintain a constant average amplitude of the detected signal, thus compensating for changes in the detection environment. The average amplitude of the transmitted signal is controlled by integrating the received signal using an integrator with a time constant longer than the time constant of the expected inclusion signals, and comparing the integrated signal to a constant reference level.The presence of microbubbles is detected and a signal comprising a string of high frequency pulses is generated while the microbubbles are present.

Abstract: A blood circulation apparatus includes a suction wand for receiving blood from a patient, a reservoir for collecting received blood, a conduit connecting the suction wand and the reservoir, an anticoagulant pump and line for introducing anticoagulant into the blood upstream of the reservoir, sensors for detecting liquid volume in the reservoir and for transmitting a corresponding volume signal, and a controller for regulating anticoagulant introduction in accordance with a predetermined program and as a function of the volume signal.

Abstract: An apparatus and method for the separation of a predetermined type of microscopic unit (e.g., islets of Langerhans) from a given medium (e.g., pancreatic digest) by centrifuging in a substantially continuous density gradient. In one embodiment, a substantially continuous density gradient solution is provided to a flexible processing bag appropriately positioned within an upper chamber of a rotating variable volume centrifuge. The solution having a plurality of the desired microscopic units therein is loaded onto the gradient and such units migrate to a particular radial position within the gradient based upon the density of such units. Once appropriately separated by the formation of regions, a fluid is provided to a lower chamber of the centrifuge bowl during continued rotation thereof to sequentially remove fractions from the processing bag from an inward location to an outward location, at least one of which fractions includes the band of the desired microscopic units.