Esophageal acid clearance

Results of an acid clearance test performed with radiolabeled 0.1 N HCl. The calculation of bolus volume within the esophagus is derived from scintiscanning over the chest. DS denotes dry swallows. Although all but about 1 mL of the infused fluid is cleared from the esophagus by the first peristaltic contraction, the distal esophageal pH initially is still reduced. Stepwise increases in distal esophageal pH occur with subsequent swallows due in part to the delivery of salivary secretions.