Flush-valve assembly for blood pressure measurement catheter

Abstract

A resilient valve core, biased against its seat in a molded body, controls large flow volumes for flushing. A small resilient tube embedded in the core bypasses the valve to provide smaller flow volumes for IV-fluid drip. For flushing, the core is deformed, rather than bodily moved, relative to the body. A fluid-flow channel is recessed along one side of the valve cavity, and the valve seat forms a short barrier across this channel. The core is a T-shaped unitary member; the center of the 'upper' surface of the T crossbar is biased against the seat, and the extrema of the crossbar are hermetically sealed against the valve body, while the stem of the T extends outward from the body. A user squeezes a cowling mounted outside the body to start and control flushing. The cowling itself deforms to pull the stem of the T outward, deforming the T and separating the middle of its crossbar portion from the valve seat. A user can elect to grasp and pull the stem directly. Parts of the upper side of the extrema of the T crossbar are relieved, forming a smooth fluid-flow transition with the inlet and outlet. These paths, the relieved parts of the crossbar, and the cavity interior are all smooth, gently tapering and well fitted, forming nearly an in-line flush path to minimize gas-bubble trapping.