US Patent 9138572 Medical valve with fluid volume alteration

A medical valve has an open mode that permits fluid flow, and a closed mode that prevents fluid flow. To that end, the medical valve has a housing having an inlet and an outlet, and a resilient member within the housing. The resilient member has a body portion with a free state when undeformed by external mechanical forces and a deformed state when the valve is in the closed mode. The body portion is formed to return toward the free state as the valve transitions from the closed mode to the open mode and defining at least part of a fluid path through the valve.