Influence of breathing pattern on the esophagogastric junction pressure and esophageal transit.

The esophagogastric junction (EGJ) is guarded by two sphincters, a smooth muscle lower esophageal sphincter (LES) and a skeletal muscle crural diaphragm. The LES relaxes in response to a swallow but the crural diaphragm does not. Since contraction of the crural diaphragm is affected by the pattern of breathing, the latter may also influence the EGJ pressure and swallow-induced EGJ relaxation. Our aims were to study the effects of alterations of the breathing pattern on the EGJ pressure, swallow-induced EGJ relaxation, and esophageal transport of liquid bolus. Manometric, electromyographic, and videofluoroscopic studies were performed in 12 healthy subjects. The subjects were trained in two types of breathing patterns, hyperventilation and partial expiration, using the visual biofeedback from their own respiratory waveform. Hyperventilation increased the frequency of inspiratory pressure oscillations at the EGJ without affecting the end-expiratory EGJ pressure. Partial expiration resulted in an increase in the end-expiratory EGJ pressure. Swallow-induced relaxation at the EGJ was markedly reduced during partial expiration. An inspiration during a swallow (control breathing and hyperventilation) caused transient interruption of flow across the EGJ. Partial expiration resulted in cessation of the flow across the EGJ, failure of esophageal peristalsis to traverse the entire length of the esophagus, increased esophageal transit time, and incomplete esophageal clearance of a liquid bolus.(ABSTRACT TRUNCATED AT 250 WORDS)