Circumferential membrane, fluid coupled catheter

Claim 1

A fully circumferentially responsive medical catheter having a longitudinal axis, and comprising: a longitudinally elongated circularly sectioned support tube for insertion into a body region to be investigted, said support tube having an internal lumen with an internal wall, and being divided into a plurality of lengths, each length having an end; a rigid insert inserted into the lumen of two adjacent lengths, making a sealing fit therewith, portions of said lengths overlapping said insert with their ends spaced apart from one another to leave a spacing between them, said insert having a cylindrical outer wall and an internal chamber, there being a port through said wall interconnecting said chamber and closing said spacing, and a closure at each end of said chamber closing the same, one closure being rigid and the other closure being elastically flexible to respond to pressure changes in the chamber; a flexible membrane extending entirely around said spacing and overlapping said ends of said lengths, whereby to close said spacing, leaving the spacing as a continuous peripheral cavity and retain a liquid within said spacing and chamber, said spacing and chamber thereby containing said liquid as an encapsulation inside said membrane; insert and closures; sensor means responsive to flexure of the flexible closure and thereby to pressure in said chamber; and connector means connected to said sensor means adapted to connect the sensor means to means for providing a signal proportional to pressure in said chamber.