Usefulness of low- and high-volume multiple rapid swallowing during high-resolution manometry

BACKGROUND: It has been suggested that multiple rapid swallowing should be added to oesophageal manometry. AIM: To prospectively evaluate whether 10 and 200mL multiple rapid swallowing provide different information concerning motor function. METHODS: 30 consecutive patients with oesophageal symptoms, 13 achalasia patients after successful pneumatic dilation and 19 healthy subjects performed eight 5mL single swallows, two 10mL and one 200mL multiple rapid swallowing. RESULTS: Almost all of the healthy subjects and two-thirds of the patients with oesophageal symptoms showed motor inhibition during both 10 and 200mL multiple rapid swallowing. The oesophago-gastric pressure gradient was significantly higher during 200mL multiple rapid swallowing within each group (p<0.01), and significantly higher in the achalasia patients than in the other two groups (p<0.0001). Presence of a contraction and increased contraction strength in comparison with single swallows were both more frequent after 10mL than after 200mL multiple rapid swallowing in the healthy subjects and the patients (p<0.05). CONCLUSION: Motor inhibition could be similarly evaluated by means of 10 and 200mL multiple rapid swallowing; 10mL evaluated the after-contraction, whereas 200mL multiple rapid swallowing was more valuable in identifying increased resistance to outflow.