Generating microbubbles for bubble studies

A method for generating microbubbles, the method comprising:

• providing a syringe comprising a barrel defining an interior volume, a plunger, a tip and a check valve assembly;
• the check valve assembly comprising:
• (i) one or more inlet ports;
• (ii) a check valve that is configured to open when the plunger is drawn back by a user;
• (iii) one or more nozzles in fluid communication with the interior volume and, when the check valve is open, in fluid communication with the one or more inlet ports;
• drawing back the plunger with the tip coupled to a source of liquid to thereby draw the liquid into the interior volume;
• removing a seal from the one or more inlet ports, decoupling the tip from the source of liquid, and sealing the tip;
• further drawing back the plunger to draw gas adjacent the inlet ports into the interior volume to form microbubbles in the liquid already drawn into the interior volume;
• unsealing the tip and coupling the tip to an intravenous line associated with a patient undergoing a bubble study;
• depressing the plunger to force the liquid and the formed microbubbles into the intravenous line.