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an effort at inhalation with a closed glottis after exhalation, used during fluoroscopic examination to cause a negative intrathoracic pressure with engorgement of intrathoracic vascular structures, which is helpful in recognizing esophageal varices, and in distinguishing vascular from nonvascular structures.
Inspiratory effort with a closed glottis at the end of expiration. This technique is used during radiographic studies to produce negative intrathoracic pressure and cause engorgement of blood vessels, thus allowing visualization of esophageal varices.
See also: Müller, Johannes P.