APPARATUS AND METHOD FOR LIMITING FREE-FLOW IN AN INFUSION SYSTEM

A detachable apparatus for limiting the rate at which a fluid is supplied to a patient by a positive pressure infusion device. The infusion device has an operating device pressure of at least approximately 2 psi. The apparatus includes a constrained flow segment (or CFS), coupleable to and detachable from the infusion device, for delivering fluid to the patient from the infusion device. The CFS has a length, an inside diameter, and a hydraulic resistance. The hydraulic resistance is a function of the length and inside diameter. When the apparatus is not in a free-flow condition, the CFS delivers fluid to the patient at a controlled flow rate determined by the operating device pressure and the hydraulic resistance of the CFS. When the apparatus is in a free-flow condition, the hydraulic resistance of the CFS limits a maximum flow rate of the apparatus to less than about 50% of the controlled flow rate. An adaptor is also provided for enabling a non-activating intravascular set ("IV set") to be used with an infusion device designed to be used only with an activating IV set. The infusion device has a detector element for detecting whether an IV set being used with the infusion device is an activating IV set. The infusion device is activated in response to detection of an activating IV set and is disabled if no such IV set is detected. The adaptor comprises an active element, independent of an IV set, for interacting with the detector element. The active element causes the detector element to detect the presence of an activating IV set when, in reality, a non-activating IV set is being used.