The present invention relates to a device for the prevention of air embolisms during a catheterization procedure. The device includes a bulb element configured to secure to a sheath assembly. The bulb element includes a flexible wall, including a proximal section and a distal section, and an interior chamber in fluid communication with a pressurized fluid source. The proximal section of the bulb element includes a proximal hub, and the distal section of the bulb element includes a distal hub. The bulb element is collapsible, under the action of an external force, from a first, relaxed state in which the interior chamber has a first volume, to a second, collapsed state in which the interior chamber has a second volume less than the first volume, and wherein the bulb element is configured to assume its first, relaxed state in the absence of the external force.