Pressure and oxygen saturation catheter

Apparatus for use in measuring the degree of oxygen saturation in blood while simultaneously measuring blood pressure and comprising:

• an elongated tubular catheter having a proximal end and a distal end with the latter being adapted to be inserted into a blood vessel within a body;
• an elongated optical fiber member carried within said catheter and extending throughout the length thereof, said optical fiber member having a light transmitting core coaxially surrounded by cladding means essentially throughout its length, said core being uncladded for at least a portion of its length proximate to the distal end thereof;
• filter means located at the distal end of said catheter and positioned forwardly of the distal end of said optical fiber member to receive light therefrom, said filter means being transmissive to light greater than that of a wavelength W, in the red and infrared wavelength region, and reflecting light at wavelengths less than wavelength W so that light of longer wavelengths may be transmitted through said filter means into blood containing both oxygenated and unoxygenated blood and be reflected therefrom back into the distal end of said catheter;
• and
• said catheter having at least one side port located adjacent the distal end thereof while proximal of said filter means and in registry with a said uncladded portion of said core, pressure transducer means located in said side port including a flexible transducer member having a pitted surface facing said uncladded core portion and making surface area contact therewith such that the contacting surface area varies with pressure applied to said transducer member acting transversely thereof, said transducer member being constructed of material exhibiting a greater index of refraction than said cladding means so that the intensity of light passing through said core proximate to said transducer means is modulated in its intensity as a function of said pressure.