Balloon dilation apparatus

Claim 1

An apparatus for performing balloon dilation and indicating the pressure and volume of the balloon during dilation comprising: a syringe for filling a balloon catheter with liquid, the syringe including a cylinder and a piston moveable axially in the cylinder effective to displace liquid in the syringe, liquid passage means adjacent an end of the cylinder for passage of the displaced liquid to the balloon catheter, a linear variable differential transformer having an axial bore and a core moveable axially in the bore effective to generate an electrical signal proportional to the core's axial position in the transformer, the syringe and the linear variable differential transformer being disposed together in end to end relationship, a shaft moveable axially within the syringe cylinder and the axial bore of the transformer, one end connected to the piston in the syringe cylinder, and the shaft in the bore of the transformer being nonferrous and carrying the core, whereby movement of the shaft causes simultaneous axial movement of the piston and the core and produces the electrical signal proportional to the core's axial position in the transformer and thereby the volume of the liquid displaced from the syringe cylinder into the balloon catheter, a pressure transducer in fluid communication with liquid in the liquid passage effective to produce an electrical signal proportional to the liquid pressure, and means for displaying the electrical signals produced by the linear variable differential transformer and the pressure transducer thereby displaying present and past values of the liquid pressure and volume existing within said balloon catheter.

Claim 2

An apparatus for performing balloon dilation and indicating the pressure and volume of the balloon during dilation comprising: a syringe for filling a balloon catheter with liquid, the syringe including a cylinder and a piston moveable axially in the cylinder effective to displace liquid in the syringe, liquid passage means adjacent an end of the cylinder for passage of the displaced liquid to the balloon catheter, a linear variable differential transformer having an axial bore and a core moveable axially in the bore effective to generate an electrical signal proportional to the core's axial position in the transformer, the syringe and the linear variable differential transformer being disposed together in end to end relationship, a shaft moveable axially within the syringe cylinder and the axial bore of the transformer, one end connected to the piston in the syringe cylinder, and the shaft in the bore of the transformer being nonferrous and carrying the core, whereby movement of the shaft causes simultaneous axial movement of the piston and the core and produces the electrical signal proportional to the core's axial position in the transformer and thereby the volume of the liquid displaced from the syringe cylinder into the balloon catheter, a pressure transducer in fluid communication with liquid in the liquid passage effective to produce an electrical signal proportional to the liquid pressure, and means for displaying the electrical signals produced by the linear variable differential transformer and the pressure transducer thereby displaying present and past values of the liquid pressure and volume existing within said balloon catheter.