Patent ID: 7729735

Claim:
A system for determining the presence of arterial blood in a vascular compartment comprising: a small diameter catheter adapted to be introduced to a vascular region using an introduction needle over which the catheter is mounted, the catheter including a distal shaft defining a lumen and a hub; a light emitter and photodetector constructed and arranged to pass light through blood from the emitter to the photodetector when the blood from the venous is drawn through the lumen from the vascular region; and a processor operatively connected to the light emitter and the photodetector that measures and indicates a level of oxygen saturation of the blood drawn from the vasular region; wherein the light emitter is positioned on a surface of the lumen that is diametrically opposed to the photodetector, such that when the blood is drawn through the lumen, the light passes from the light emitter through the blood to the photodetector, to allow measurement of light absorbed by the blood moving between the light emitter and the photodetector as the blood is drawn through the lumen.