System for detecting and removing gas bubbles from a vascular infusion line, including a cassette adapted for disposition intermediate the fluid line, the cassette including a flexible tube having an inlet port for connection to a supply side of the fluid line, an outlet port configured for connection to a patient side of the fluid line, and a purge port intermediate the inlet and outlet ports, and a base unit adapted to receive the cassette and monitor fluid flow through the tube, the base unit including a sensor to detect the presence of a gas bubble in the fluid flow, a pinch valve adapted to stop the flow of fluid, and a control unit adapted to operate the base unit so that (i) fluid is permitted to flow past the pinch valve when no gas bubble is detected; and (ii) fluid flow is arrested when a gas bubble is detected.