Syringe Assembly Having Re-Use Prevention Features

A single-use medical device comprising:

• a barrel including a cylindrical sidewall having an interior surface defining a chamber for retaining fluid, an open proximal end and a distal end including a distal wall having an opening therethrough in fluid communication with said chamber;
• an elongate plunger rod including a proximal end, a distal end having an end wall and a stopper in fluid-tight engagement with the inside surface of the barrel, and a main body extending between the proximal and distal end, the proximal end including a thumb press, the stopper adapted to form a vacuum with the barrel within the chamber;
• and
• means for breaking the vacuum, the plunger rod being distally and proximally movable within said chamber for at least two aspiration and expulsion cycles.

A method of using a syringe comprising:

• providing a syringe having a barrel including a cylindrical sidewall having an interior surface defining a chamber for retaining fluid, an open proximal end and a distal end including a distal wall having an opening therethrough in fluid communication with said chamber;
• and an elongate plunger rod including a proximal end, a distal end having an end wall and a stopper in fluid-tight engagement with the inside surface of the barrel, and a main body extending between the proximal and distal end, the plunger rod being distally and proximally movable within said chamber, the proximal end including a thumb press;
• aspirating a predetermined amount of fluid into the chamber by applying a proximally directed force on the plunger;
• expelling the fluid by applying a distally directed force on the plunger rod;
• and
• applying a sufficient force in the distal direction to the plunger rod to disable the stopper to prevent the creation of a vacuum between the stopper and syringe barrel upon application of a proximally directed force to the plunger rod.