Sequential medical fluid aspiration and injection system and method

Abstract

A system for the sequential and repetitive aspiration and injection of fluid. The system includes a syringe having an internal volume, a piston to vary the internal volume and a chamber divider for separating the internal volume into proximal and distal reservoirs. The chamber divider is moveable along the chamber and is positioned adjacent the distal end of the chamber prior to withdrawal of fluid into the syringe. The proximal reservoir has a maximum displacement volume for receiving fluid. A flow channel provides flow between the proximal and distal reservoirs and a valve disables and enables flow therethrough. A tensile element links the piston and the chamber divider so that after the piston is moved and the proximal reservoir is filled with a first liquid, the chamber divider is pulled away from the distal end of the syringe to enlarge the distal reservoir and draw the blood into the distal reservoir. A conduit is connected with the syringe and is in communication with the patient's blood vessel and contains the first liquid. The flow channel and the conduit are sized and configured such that after the maximum volume of first liquid has been withdrawn into the proximal reservoir and the blood has been withdrawn into the distal reservoir, the maximum volume of first liquid is substantially free from blood, and subsequent displacement of the maximum volume of first liquid back through the valve is sufficient to displace all the blood from the syringe when the piston is advanced.