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

Abstract

We previously developed a technique to study the effect of inhibitory innervation in the human oesophageal body, by creating an artificial high pressure zone (artificial HPZ) using an intra-oesophageal balloon. Swallowing 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 contraction of the oesophageal wall at that level. Studies were performed in five healthy subjects. Oesophageal pressures 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 the artificial HPZ. A barostat bag was glued to the opposite side of the balloon. The pressure in the barostat bag was pre-set at 8 mmHg below the pressure measured in the artificial HPZ. We studied deglutition-induced variations in the barostat bag volume after single and multiple swallows. Immediately after single swallows and during multiple swallows, we observed a fall in pressure in the artificial HPZ and a significant increase 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. The swallow-induced fall in pressure in the artificial HPZ represents a real relaxation of a segmental tonic contraction of the oesophageal wall due to deglutitive inhibition. The oesophageal artificial HPZ is a simple method that can be used to study inhibitory phenomena in the body of the human oesophagus.