Abstract: The sensor and memory unit (30, 92 or 94) includes a sensor assembly (34) having at least one sensor (48, 50 or 96) therein and a memory (18, 22, 70, 98) associated and fixed therewith. In one embodiment the memory (70, 98) is mounted in a memory module (38 or 90) which is connected by a multiconductor lead (40 or 88) to the sensor or sensors (48, 50 or 96). Also the sensor assembly (34) can be fixed in the distal end (36) of a catheter (32).The sensor and memory unit (94) can be coupled to signal processing and conditioning circuitry (76, 176 or 276) which can include a microprocessor (178) for processing the sensor (96) signals and conditioning/correcting same based upon the information data retrieved from the memory (98).

Abstract: A catheter tip pressure transducer is employed for purposes of measuring fluid pressure within a living body. This includes a tubular housing having a pressure inlet aperture therein. A semiconductor block is carried within the housing and has first and second oppositely facing surfaces, one of which faces the inlet aperture and the other faces in the opposite direction. One of the surfaces has a recess formed therein of such a depth to define an elongated rectangular shaped membrane. A pair of elongated grooves are formed in the nonrecessed surface of the semiconductor block. These grooves are in registry with and straddle the longitudinal side edges of the membrane and define therebetween a raised longitudinally extending central portion in the form of a membrane beam which acts as a free beam supported at its opposite ends by the semiconductor block.

Abstract: The measuring device (10) comprises an ISFET (12) used as a chemically selective ion sensor, a reference electrode (20) positioned adjacent the ISFET (12), an amplifier (22) coupled to the ISFET and control/correction circuitry (30) coupled to the ISFET (12), to the reference electrode (20) and to the amplifier (22). The control/correction circuitry (30) is operable to maintain the drain-source current I.sub.DS of the ISFET (12) at a constant value and to correct drift effects of the ISFET (12) on the basis of the logarithmic equation:.DELTA.V.sub.p =A 1n(t/t.sub.o +1 )where:.DELTA.V.sub.p =potential driftA=scale factor for drift and amplitudet.sub.o =time constant defining the dependence on timet=time during which the sensor is operative in the event of continuous operation.

Abstract: The apparatus (10) for determining the activity of an ion (pIon) in a liquid (16) comprises a measuring circuit (10) including an ion sensitive field effect transistor (ISFET 12), a reference electrode (32) adjacent the ISFET (12), a temperature sensor (34) adjacent the ISFET (12), amplifiers (22 and 38) coupled to the ISFET (12) and temperature sensor (34), and control, computing and memory circuits (30, 44, and 46) coupled to the amplifiers and operable to maintain two of the following three parameters, V.sub.gs (gate-source potential), V.sub.ds (drain-source potential) and I.sub.D (drain-source current) at a constant value so that the third parameter can be used for determining the ion activity or pIon. The pIon sensitivity of the apparatus (10), as a function of temperature and/or the variation of the drain-source current, I.sub.D, as a function of the temperature are controlled by controlling the V.sub.gs so that the pIon can be calculated from a formula stored in the memory (46 ).

Abstract: An oxygen sensor and method of monitoring the oxygen content of blood or other body fluids are provided, which oxygen sensor and method achieve monitoring of enhanced accuracy that is not substantially effected by the presence of an anaesthetic within the fluid being monitored. The electrolyte used in connection with this invention includes a preferential adsorption component that exhibits adsorption to the cathode of the sensor which is in preference to adsorption of the anaesthetic to the cathode of the sensor.

Abstract: Conjugates are provided which are covalently bonded conjugates of an anticoagulant and protein that are prepared in the presence of a coupling agent that forms amide linkages between the anticoagulant and the protein. Such amide linking coupling agents exclude highly toxic coupling agents such as CNBr. These conjugates are useful for enhancing the blood compatibility of certain surfaces of a prosthetic device, a surgical apparatus, or an extra-corporeal medical device.