Rapid air infusion into the oesophagus: Motor response in patients with achalasia and nonobstructive dysphagia assessed with high-resolution manometry

Background: Achalasia is a neurodegenerative disorder of the oesophagus. Alteration of motor activity induced by oesophageal distension has not been explored. Objectives: To investigate this function, using high-resolution Manometry. Methods: This study enrolled 15 healthy subjects, 15 nonobstructive dysphagia (NOD), and 18 achalasia patients successfully treated with pneumatic dilation (six with restored peristalsis). The three groups underwent five rapid (<1 s) intraoesophageal infusions of 20-ml air boluses, followed by eight 5-ml water swallows. Results: Whereas the response rate to water swallows was similar in the three groups, air infusion induced a lower response rate in achalasia (median, interquartile range: 70%, 40–100%) and, to a lesser extent, in NOD patients (100%, 60–100%) than in healthy subjects (100%, 100–100%; p<0.001 and p=0.06, respectively). However, the response rate was highly variable in achalasia patients irrespective of presence of peristalsis. Furthermore, the strength of motor response to air infusion when compared to water swallows was diminished in achalasia patients but not in healthy subjects and NOD. Conclusions: Motor response to rapid air infusion was variably impaired in achalasia. The role of this alteration in the longterm outcome deserves evaluation.