Remote sensing tonometric catheter apparatus and method

Claim 1

A tonometric catheter and secondary apparatus for measuring a liquid fluid or gaseous fluid property indicative of the condition of an internal organ of a human or other mammal in vivo, comprising: (a) an elongated tube having a tonometric catheter lumen extending longitudinally therethrough, said tube being composed of a first elastomeric material that is substantially impermeable to one or more liquid fluids or gaseous fluids of interest, said fluids of interest including oxygen gases and carbon dioxide gases; (b) at least one walled sampling chamber on said tube in fluid communication with the interior of said tonometric catheter lumen, said walled sampling chamber being defined by a balloon member generally surrounding a portion of said tube and sealingly interconnected therewith, the wall of said balloon member being composed of a second material that is freely and selectively permeable to said one or more liquid fluids or gaseous fluids of interest, said second material being substantially impermeable to other liquid fluids or gaseous fluids, and said balloon member being inflated for forming an interior space between said balloon member and said tonometric catheter lumen and for selectively positioning a portion of said balloon member substantially in direct contact with a wall portion of the internal organ in order to allow said one or more liquid fluids or gaseous fluids of interest from the tissue of the wall portion of the internal organ to permeate into said sampling chamber, with said tube extending to a position outside of the body of the human or other mammal, and with said tonometric catheter lumen providing fluid communication between said sampling chamber and the outside of the body of the human or other mammal; (c) sensor means for sensing the level of at least one of said liquid fluids or gaseous fluids of interest from the tissue of the wall portion of the internal organ present within said sampling chamber, said sensor means being disposed within said sampling chamber; and (d) said secondary apparatus including a second lumen extending longitudinally through said tube and being adapted for the delivery or draining of a liquid or gaseous fluid to or from the internal organ.