CATHETER FOR USE IN DETECTING DISSOLVED GAS IN FLUIDS SUCH AS BLOOD

摘要

A blood catheter including a cannula covered with a thin layer of silicone rubber or other material permeable to one or more of the gases that are or might be found in blood and wherein the cannula preferably includes a helical arrangement of apertures for enabling the diffusion of gas through the membrane and into the center portion of the cannula. The helical pattern of apertures around the periphery of the cannula enables the catheter to contact the interior wall of a blood vessel without restricting blood flow past more than a small fraction of the total number of apertures. Other hole configurations can be used, for example, when a plurality of holes are located at spaced axial locations along the cannula and at spaced intervals around the circumference of the cannula at the various axial locations.