INJECTION SITE FOR FLOW CHAMBER

摘要

In a fluid administration set of otherwise conventional design, an in-line chamber is provided having an inlet and outlet port communicating with the chamber and defining part of the path of flow through the set. A sealing piston is slidably movable by fluid pressure within the chamber and capable of occupying first positions in which the sealing piston isolates fluid in the chamber adjacent the inlet port from fluid in the chamber adjacent the outlet port. The sealing piston also can occupy at least one second position in which unlimited fluid flow is permitted between the inlet port and outlet port. A third port is provided for intermittently inserting a critical fluid into the chamber on the side of the sealing piston facing the outlet port. Thus the piston can be driven into the first position from the second position by this insertion, to prevent mixing of the critical fluid with fluid on the side of the piston facing the inlet port until the critical fluid has substantially passed through the outlet port and the piston moves to the second position. This permits the reliable, prompt administration of essentially the entire dose of a critical medication, particularly at low flow rates.