Abstract: A method for generating microbubbles may include providing a syringe having a barrel defining an interior volume, a plunger, a tip and a check valve assembly. The check valve assembly may have an inlet port; a check valve that is configured to open when the plunger is drawn back by a user; and a nozzle in fluid communication with the interior volume and, when the check valve is open, in fluid communication with the inlet port. The method may include drawing liquid into the interior volume; removing a seal from the inlet port and drawing gas adjacent the inlet ports into the interior volume to form microbubbles in the liquid already drawn in; coupling the tip to an intravenous line associated with a patient undergoing a bubble study; and depressing the plunger to force the liquid and the formed microbubbles into the intravenous line.

Abstract: A method may include intravenously directing first bubbles into a patient's venous circulatory system and to a right side of the patient's heart. The first bubbles may have sizes that fall within a first range. The method may further include monitoring the patient's heart, with ultrasound imaging, to detect presence of the first bubbles on a left side of the patient's heart. Upon detecting the first bubbles on the left side of the patient's heart, the method may further include intravenously directing second bubbles into the patient's venous circulatory system and to the right side of the patient's heart. The second bubbles may have sizes that fall within a second range that is different than the first range. Upon detecting the second bubbles on the left side of the patient's heart, the method may further include initiating treatment to minimize risk of stroke in the patient.

Abstract: A method may include intravenously directing first bubbles into a patient's venous circulatory system and to a right side of the patient's heart. The first bubbles may have sizes that fall within a first range. The method may further include monitoring the patient's heart, with ultrasound imaging, to detect presence of the first bubbles on a left side of the patient's heart. Upon detecting the first bubbles on the left side of the patient's heart, the method may further include intravenously directing second bubbles into the patient's venous circulatory system and to the right side of the patient's heart. The second bubbles may have sizes that fall within a second range that is different than the first range. Upon detecting the second bubbles on the left side of the patient's heart, the method may further include initiating treatment to minimize risk of stroke in the patient.