Small-sized disposable pressure transducer apparatus with a temperature compensating circuit disposed adjacent a passageway coupled with a catheter

Claim 1

In a disposable pressure transducer apparatus for use in blood pressure measurement, said apparatus comprising a housing having an interior and a wall portion in which a passageway is formed to be coupled with a catheter, said passageway being for introduction of a fluid through said catheter inserted into a blood vessel, a dielectric substrate having a first surface and an opposite second surface, said substrate being fixedly mounted in said interior of the housing with said second surface being onto an inner surface of said wall portion, a semiconductor pressure sensor mounted on said first surface of said substrate and hydraulically coupled with said passageway, and an electric circuit including a temperature compensating circuit and being mounted on said substrate, said electric circuit being electrically connected to said semiconductor pressure sensor and to electric conductive means for electrically connecting said electric circuit with a monitoring device, the improvement wherein said first surface of said substrate has a first specific area on which said semiconductor pressure sensor is mounted and the remaining area as a first particular area, said second surface has a second specific area corresponding to said first specific area and the remaining area has a second particular area, said temperature compensating circuit is formed on said second particular area, said wall portion is provided with an abutment slightly projecting from said inner surface, and said substrate is fixed at said second specific area onto said abutment so that said temperature compensating circuit on said second particular area is positioned to face said inner surface of said wall portion with a small gap.