Measurement of integrated relaxation pressure (IRP) on an esophageal pressure topography plot

The IRP is a complex metric that involves localizing the margins of the esophagogastric junction (EGJ), demarcating the time window following deglutitive upper sphincter relaxation within which EGJ relaxation will occur, and applying an e-sleeve measurement within that 10-second time box. The IRP pressure in mmHg is the mean pressure during the four seconds during which the e-sleeve value was least. In this example, the heavy black line is the 8 mmHg isobaric contour, which isolates the 4 seconds of maximal EGJ relaxation, interrupted by a crural contraction. The IRP value (5.3 mmHg) is the mean e-sleeve pressure during the two time intervals circumscribed with ovals.