| abstract |
A parameter of blood is sensed in vivo with a system which includes a catheter (53) and a probe. The catheter has a lumen (61) extending therethrough, a proximal end, a distal end (59) and a distal opening (63) at the distal end. The probe includes one or more sensing elements (69, 71, 73) at its distal end. In one embodiment, the sensing element or elements are located at least about 4 mm proximal of the distal opening of the lumen. A volume oscillator is provided to control the movement of blood into and out of the lumen. A flush solution is introduced into the lumen so that when the volume oscillator is inactive the sensing element or elements are exposed to pure flush solution, which preferably includes an anti-clotting component. The probe is received within the catheter and affixed thereto. The volume oscillator is activated to move blood into and out of the lumen to expose the sensing element or elements to blood so that they can sense the blood parameter or parameters of interest. |