Catheter transducer for in vivo measurements

Claim 1

IN A DEVICE FOR MAKING IN VIVO MEASUREMENTS OF A CONSITUTENT IN A BODY FLUID OR THE LIKE, COMBINATION OF: A CATHETER; ELECTROCHEMICAL SENSOR MEANS IN ONE END OF SAID CATHETER, SAID SENSOR MEANS INCLUDING A PAIR OF ELECTRODES ONE OF SAID ELECTRODES SURROUNDING AND BEING CONCENTRICALLY MOUNTED WITH RESPECT TO THE OTHER ELECTRODE AND SPACED THEREFROM, AN ELECTROLYTE JOINING SAID ELECTRODES AND A MEMBRANE PERMEABLE TO THE CONSTITUENT BEING MEASURED SEPARATING SAID ELECTRODES AND ELECTROLYTE FROM THE BODY FLUID; FIRST AND SECOND CONDUCTORS ELECTRICALLY CONNECTED TO SAID ELECTRODES AND EXTENDING THROUGH SAID CATHETER TO THE OTHER END THEREOF, A NONCONDUCTIVE TUBE SURROUNDING SAID FIRST CONDUCTOR, SAID SECOND CONDUCTOR COMPRISING A WIRE SPIRALLY WOUND OVER SAID NONCONDUCTING TUBE TO FORM A COIL, AND EACH CONVOLUTION OF SAID COIL ABUTTING THE NEXT ADJACENT CONVOLUTION THEREOF TO THEREBY PROVIDE HIGHLY FLEXIBLE ELECTRICAL SHIELDING FOR SAID FIRST CONDUCTOR; AND MEANS AT SAID OTHER END OF SAID CATHETER CONNECTED TO SAID FIRST AND SECOND CONDUCTORS FOR CONNECTING SAID CONDUCATORS TO AN EXTERNAL CIRCUIT.