Abstract: Sensing composition precursors and sensing compositions, useful in sensing the concentration of a gas, e.g., carbon dioxide, in a medium, e.g., blood, are disclosed. In one embodiment, the sensing composition precursor comprises a dispersed aqueous liquid including a sensing component dissolved therein, a polymer precursor, and a hydrophilic dispersing agent selected from hydroxyalkyl celluloses and mixtures thereof in an amount effective to facilitate maintaining the dispersed aqueous liquid.

Abstract: A method for making a sensing element, and an assembled sensing element, useful in sensing the concentration of a gas, e.g., carbon dioxide, in a medium, e. g. blood, are disclosed. In one embodiment, the method comprises placing a quantity of a sensing composition precursor between and in contact with a transparent, gas impermeable solid disc and an opaque, gas permeable film, the sensing composition precursor comprises a sensing component, a polymer precursor and a cross-linking agent; and forming a gas sensing composition from this quantity of sensing composition precursor.

Abstract: An endless path calibration system comprising a sensor cassette having a flow-through passage and at least one sensor to be calibrated, a chamber coupled to the sensor cassette to define an endless path and a sterile calibration liquid in the endless path. A gas injection passage for injecting gas into the sterile calibration liquid and a gas vent leading from the endless path to the exterior of the endless path. A check valve allows gas to escape from the endless path and substantially prevents gas and liquid from entering the endless path through the gas vent.

Abstract: An apparatus for holding a fluid under pressure, including a container for containing the fluid under pressure and a valve mounted on the container. The container has a passage leading to the exterior of the container, and the valve has an actuator for moving the valve between closed and open positions. A locking device is responsive to movement of the actuator to a position in which the valve is open to lock the actuator against movement that would close the valve. Consequently, the valve is locked in the open position.

Abstract: An apparatus for sensing the concentration of a component such as oxygen in a medium such as blood. The apparatus includes an elongated signal transmitter and a sensing element at one end thereof. A substantially rigid sleeve is secured around such end to provide a pocket for the sensing element.

Abstract: An apparatus comprising a housing, a curved wall surface on the housing and a tube compressor carried by the housing. A compressible tube, which defines at least a portion of the passage, is positioned between the curved wall surface and the tube compressor. The tube compressor is mounted on the housing for free radial movement relative to the curved wall surface and for rotational movement. The tube compressor can be releasably drivingly coupled to an external rotary input so that the tube compressor can be rolled along the tube to pump fluid in the tube.

Abstract: An endless path calibration system comprising a sensor cassette having a flow-through passage and at least one sensor to be calibrated, a chamber coupled to the sensor cassette to define an endless path and a sterile calibration liquid in the endless path. A gas injection passage for injecting gas into the sterile calibration liquid and a gas vent leading from the endless path to the exterior of the endless path. A check valve allows gas to escape from the endless path and substantially prevents gas and liquid from entering the endless path through the gas vent.

Abstract: An apparatus for sensing the concentration of a component such as oxygen in a medium such as blood. The apparatus includes an elongated signal transmitter and a sensing element at one end thereof. A substantially rigid sleeve is secured around such end to provide a pocket for the sensing element.

Abstract: An assembly useful in conjunction with a signal transmission means for the measurement of a compositional parameter of the blood of a patient is disclosed. This assembly comprises a housing adapted and sized to be located outside the body of a patient and having a fluid flow passage therethrough into which blood from the patient is passed from a hollow tube, the fluid flow passage being defined by a wall which is substantially impermeable to blood, the housing being adapted to be removeably secured to a signal transmission system such that the housing is capable of being removed from the signal transmission system without disrupting the fluid flow passage; and a sensing element located in the housing in or near the fluid flow passage for providing a signal directly to the signal transmission system in response to a compositional parameter of blood located in the fluid flow passage.

Abstract: An apparatus for measuring the concentration of a component in a medium comprising:an optical sensor including at least one optical indicator for providing an optical signal which varies in response to the presence of a component in a medium;an optical signal fiber capable of transmitting the optical signal from the optical sensor; anda supply reservoir associated with the optical sensor and acting to provide additional optical indicator to the optical sensor.

Abstract: A parameter of blood is sensed with a system which includes a catheter and a sensor and a volume oscillator element. The catheter has a lumen extending therethrough, a proximal end, a distal end and an opening, adapted to be placed in the blood vessel of a patient. The sensor senses a blood parameter and is adapted to be located outside the patient's body in fluid communication with the lumen. The volume oscillator element is in fluid communication with the lumen and is capable of acting to periodically cause blood to enter and exit the lumen. The system is structured so that a flush or anti-clotting solution flows into the patient when the volume oscillator element is inactive. With the volume oscillator activated, blood is moved back and forth in the lumen to expose the sensors to blood so that the blood parameter of interest can be sensed.