Catheter electrode for oxygen polarography

Claim 1

An electrode assembly for use in oxygen polarography comprising an elongated tubular insulating plastic shell, a gaspermeable plastic membrane closing the distal end of said shell, an elongated tubular metal housing screw-threaded adjacent its distal end, said shell being correspondingly screw-threaded from its proximal end and said tubular housing being screwed into said shell to a point approximately midway between the ends of said shell, the proximal end of said shell being at a point approximately midway between the ends of said tubular housing, whereby approximately half of said tubular housing projects proximally from said shell, a cylindrical insulating electrode base having a larger portion fitting and secured in the bore of said tubular housing and a cylindrical stem integral with said larger portion and projecting distally therefrom, a first passage extending axially of said base and stem, a second passage extending axially of said larger portion, a cathode mounted at the distal end of said stem and having a lead extending through said first passage, an anode projecting distally from said larger portion adjacent to said stem and having a lead extending through said second passage, and a quantity of electrolyte confined within a space bounded by said shell, said membrane and the distal ends of said base and said tubular housing, the proximally extending portion of said tubular housing being adapted to fit within and be secured to a substantial distal portion of a catheter.