Abstract: An apparatus for determining pressure at one or a number of intermediate points along a catheter inserted into a closed cavity. Fiberoptic cables extend from the proximal end of the catheter to the intermediate points at which pressure measurements are taken as well as to the distal tip of the catheter. The fiberoptic cables transport light signals injected at the proximal end and said light signals are illuminated in the direction of a flexible, reflective membrane. A pressure sensing coupler interconnects proximal and distal sections of the catheter sheath and also houses the pressure sensor. The pressure sensing coupler includes a plurality of radial ports which provide communication between the fluid in the cavity and a pressure sensing chamber, which is also in communication with the reflective membrane. The pressure sensing coupler also enables the passage of inner catheters through axial passageways for interconnection to other distally located pressure sensors.

Abstract: A vascular catheter comprises an elongated, flexible tubular catheter body. In accordance with this invention, a relatively rigid tunnel member is carried laterally on the catheter body outside of the catheter body. The tunnel member defines an open, non-collapsible, longitudinal passageway for blood flow outside of the catheter body when the vascular catheter is inserted in a blood vessel of a patient.