Abstract: Continuous or periodic measurement of blood gas parameters and blood pressure by separating plasma from blood and then using that plasma to measure the blood parameters. Plasma is separated from blood in vivo with a filter implanted within a blood vessel, and the separated plasma is removed to extracorporeal apparatus for analyzing blood gas parameters or measuring blood pressure. The use of plasma is equivalent to the use of whole blood for measuring blood gas parameters as the gas parameters reside in the plasma, not in the separated blood cells which remain in the blood vessel. This arrangement permits the continuous measurement of blood gases without removal of blood from the body.

Abstract: A device for being implanted in a blood vessel for carrying out continuous in vivo plasma separation comprises an elongated, axial header and at least one elongated microporous fiber having a hollow interior, said fiber being dimensioned to be received within a blood vessel without significantly obstructing fluid flow through said blood vessel, the pore size of said fiber being sufficient to allow plasma to diffuse through said pores into said hollow interior of said fiber but not sufficient to allow cellular components larger than plasma to diffuse therethrough, said one or more fibers extending laterally relative to the axis of said header and in fluid communication with said header.

Abstract: Selective separation of blood cholesterol by cascade filtration. An in vivo filter is implanted within a blood vessel to separate plasma from blood, and the separated plasma is removed to an extracorporeal secondary filter which removes low density lipoprotein (LDL) from the plasma. The in vivo portion of the apparatus comprises a number of microporous hollow fibers sized to permit diffusion of plasma, but not cellular or other larger blood components, through the fiber pores to the hollow interior of the fibers. The secondary filter passes the removed plasma along membrane walls formed by fibers sized to block passage of LDL while permitting passage of other plasma components, so that approximately 95 percent of LDL is separated from the plasma before the plasma is returned to the body in real time after removing the LDL cholesterol.

Abstract: Kidney dialysis in which metabolic waste products are removed from plasma instead of blood. Plasma separation takes place in vivo through a filter implanted within a blood vessel, and the separated plasma is removed to an extracorporeal dialysis apparatus for separating waste products from the plasma. The plasma then is returned to the bloodstream. Plasma flow in the system is significantly less than blood flow used in current hemodialysis systems, so that the present system performs dialysis continuously in real time to eliminate the extreme swings of toxicity associated with high-volume hemodialysis.

Abstract: An apparatus for the continuous in vivo separation of plasma from other blood components comprising a bundle of microporous hollow fibers inserted into the vena cava. The fibers are sized to permit diffusion of plasma through the fiber pores but not cellular or other larger blood components. The fibers are in fluid communication with a dual lumen catheter which removes plasma from the hollow fibers to a treatment system and returns treated plasma to the bloodstream. The apparatus can be incorporated into an ambulatory plasma separator system for providing continuous plasma treatment while the user is mobile.

Abstract: A very small uniform fluid stream is produced and kept constant over a prolonged period by using at least one fluid-permeable membrane which can be composed of hollow filaments, and the method and apparatus can be used, for example in cardiac catheterization and blood pressure measurement in the blood.

Abstract: An intimate mixture is prepared of a conductive metal powder and an active material in granular form. The mixture is then sintered by passing it through a variable magnetic field which is varied to produce trains of pulses in which the durations of the trains and intervals between trains are chosen in such a manner as to ensure that said metal powder is sintered without deteriorating said grains of active material.