Fiber optic catheter

Claim 1

A fiber optic catheter for use in measuring amounts of diffuse reflection of light in blood, said catheter having a multiplicity of light-conducting fibers and a catheter tubing surrounding said fibers, the fibers all being intimately juxtaposed adjacent the distal end of said catheter with corresponding end faces thereof exposed at said distal end and separated into a pair of branches adjacent the opposite proximal end of said catheter, corresponding fibers of each branch being intimately juxtaposed and respective end faces thereof exposed; wherein the improvement comprises; a rigid ball disposed forwardly of said exposed faces of said fibers at said distal end of said catheter and spaced away therefrom a distance greater than a maximum distance of penetration of light into blood whereby light emitted from said exposed faces of said fibers will be prevented from reaching said ball when said distal end of said catheter is placed in blood, said ball further being formed of a substance which characteristically reflects a fixed ratio of at least two preselected wavelengths of light directed thereupon from said exposed faces of said fibers at said distal end of said catheter when said distal end including said exposed faces and said ball is disposed in air and clear liquids; and a pair of slender posts supporting said ball in said spaced relationship with said fiber faces, said posts respectively extending from approximately diametrically opposed sides of said ball in a direction longitudinally of said catheter tubing and being secured to said distal end of said catheter for completing the configuration of a cage permitting a free flow of blood between said ball and adjacent fiber faces when said catheter distal end is placed in said blood for testing thereof, said cage further preventing contact of said exposed fiber ends with walls of means containing said blood.