Figure 16 - Success or failure of individual provocative maneuvers (coughing, leg lifting, abdominal compression, Valsalva) at eliciting gastroesophageal reflux as a function of lower esophageal sphincter (LES) pressure among groups of normal controls, patients without hiatus hernia and patients with radiographically defined hiatus hernia.

Lower esophageal sphincter pressure values were determined immediately prior to the onset of the maneuver. Open circles indicate individual trials of provocative maneuvers associated with gastroesophageal reflux, whereas solid circles indicate trials in which reflux did not occur. Reflux by the stress mechanism was much more easily elicited among the hiatus hernia patients. (Source: Sloan et al.,⁵⁰ with permission from American College of Physicians.)