Abstract: Measurement of a physiological pressure is accomplished by placement of a pressure transmitting catheter within a blood vessel or other structure within which pressure is to be measured. The catheter is blood-compatible, capable of withstanding handling during distribution and implantation, and provides adequate pressure transmission frequency response in a variety of applications. The catheter, which includes a hollow flexible tube filled with a low viscosity fluid and having a plug of a gel-like material at its distal end, transmits the pressure signal to a solid-state transducer which is typically connected to amplifying electronics and an implantable radio-transmitter capable of relaying the pressure information from within the body to a radio receiver located external to the body.

Abstract: A device capable of sensing pressure allows the sensor and amplifying electronics to be packaged in a very small size and implanted within the body. The sensor consists of a small catheter, the tip of which is placed at the point at which pressure is to be measured, attached to a solid-state pressure sensor. The catheter is filled with a fluid and is connected to an implantable infusion pump which dispenses through the lumen of the catheter, heparin or other drug which inhibits thrombogenisis.

Abstract: A telemetry system includes a transmitter, which is either placed in the vagina or is implanted in the vulvular or vaginal tissue, and a receiver. The transmitter is capable of measuring physiological parameters which are indicative or predictive of the occurrence of estrus. These parameters may include but are not limited to tissue impedance, temperature and activity of the animal. This provides a pulsed method of measuring impedance of vulvular or vaginal tissue which enhances the marketability of such a device by reducing its size, weight and complexity without sacrificing accuracy or reliability. Data telemetered from this device is preferably collected by a computer and automatically analyzed to provide a report to the farm manager as to which animals are in estrus or are expected to be in estrus at a given time.