intravenous controller, any of several devices that automatically deliver IV fluid at selectable flow rates. The controller is commonly equipped with a rate selector, drop sensor, and alarm. When the infusion does not flow at the prescribed rate, the drop alarm emits a visual and an audible signal. The IV controller works by gravity, so the IV container must be placed at least 30 inches (76.20 cm) above the venipuncture site. The controller cannot exert the positive pressure of a true pump and is not recommended for the delivery of highly viscous fluid or for maintenance of an open arterial line. Compare intravenous peristaltic pump, intravenous piston pump, intravenous syringe pump.
