The 'artificial high pressure zone'. A non-invasive method to study in manthe effect of the inhibitory innervation to the oesophagus. Validation study using a combined manometric-barostat technique

Objective We previously developed a technique to study the effect of inhibi tory innervation in the human oesophageal body, by creating an artificial h igh pressure zone (artificial HPZ) using an intra-oesophageal balloon. Swal lowing provokes a fall in pressure in the artificial HPZ that precedes the peristaltic contraction. We aimed to prove that the swallow-induced fall in pressure in the artificial HPZ is due to relaxation of a segmental tonic c ontraction of the oesophageal wall at that level. Methods Studies were performed in five healthy subjects. Oesophageal pressu res were measured at 5, 10 and 15 cm above the lower oesophageal sphincter. A rubber balloon opposite the middle pressure sensor was used to induce th e artificial HPZ. A barostat bag was glued to the opposite side of the ball oon. The pressure in the barostat bag was pre-set at 8 mmHg below the press ure measured in the artificial HPZ. We studied deglutition-induced variatio ns in the barostat bag volume after single and multiple swallows. Results Immediately after single swallows and during multiple swallows, we observed a fall in pressure in the artificial HPZ and a significant increas e in the barostat bag volume (254 +/- 67%) from 0.99 (0.37-1.93) to 3.74 (1 .91-4.34) (P = 0.005) denoting oesophageal wall relaxation. Conclusion The swallow-induced fall in pressure in the artificial HPZ repre sents a real relaxation of a segmental tonic contraction of the oesophageal wall due to deglutitive inhibition. The oesophageal artificial HPZ is a si mple method that can be used to study inhibitory phenomena in the body of t he human oesophagus. (C) 1999 Lippincott Williams & Wilkins.