Abstract: An endless loop 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 loop, a calibration liquid in the endless loop, and a valve element which is employed to prevent the flow of calibration liquid through the endless loop. This valve element, preferably carried by a housing, urges a tube compressor to squeeze a compressible tube against a curved wall surface sufficiently to prevent fluid from flowing in the compressible tube across the zone, and to maintain the at least one sensor in the sensor cassette wet with calibration liquid for long term storage of the calibration system.

Abstract: A system for monitoring physiological conditions in humans and other animals includes a transducer for monitoring such conditions as blood pressure, a monitor for displaying or recording signals from such transducers, or both, and a connector for linking the transducer to the monitor and for transforming the impedance level of signals from such transducer to levels appropriate for such monitors and for drawing and adapting power from the monitor for effecting this impedance transformation. The connector may also include a mechanism for adjusting the offset or sensitivity of the signal from the transducer, a mechanism for detecting the absence of the transducer, and a mechanism for detecting an open circuit between the monitor and the transducer.

Abstract: An apparatus comprising a valve body having first, second and vent ports and a generally tubular valve element having a peripheral wall with first, second and vent openings in the peripheral wall leading to the interior of the tubular valve element. The valve element is mounted in the valve body for rotational movement between first and second rotational positions and for axial movement between first and second axial positions. A pressure sensor is exposed to the fluid pressure within the valve body. In the first rotational position of the valve element, drip flow is provided between the first and second ports, and in the second rotational position, the vent port is open to provide communication between the pressure sensor and the atmosphere. To provide flush flow between the first and second ports, the valve element is moved to the second axial position.

Abstract: Calibration testing of a blood pressure transducer can be performed in immediate proximity to the body of the patient by including in either the transducer housing or the housing of a connector located adjacent thereto, a pair of membrane switches on opposite sides of the housing. The switches are connected in series with each other and with a shunting resistor which, when connected across one input and one output port of the transducer's circuit, will produce a predetermined pressure reading. The switches are so arranged as to require simultaneous actuation from two sides of the housing to prevent accidental actuation of the testing circuit by the patient.