STIMULUS AND SITE-SPECIFIC INDUCTION OF HICCUPS IN THE ESOPHAGUS OF NORMAL SUBJECTS

Background-Hiccups that are induced by a large meal have been suggeste d to result from gastric overdistension. The role of the oesophagus in precipitating hiccups has never been defined. Aims-To determine the i nvolvement of oesophageal mechanoreceptors in the hiccup reflex. Metho ds-Ten normal healthy subjects were prospectively evaluated at a unive rsity affiliated hospital. Controlled inflation of a polyethylene bag in the proximal and distal oesophagus was carried out using slow ramp and rapid phasic distensions, by an electronic distension device. Resu lts-Hiccups were induced in four subjects only during rapid phasic dis tensions and only in the proximal oesophagus. The mean (SEM) minimal v olume threshold for the hiccup reflex was 32.5 (4.8) ml, which was abo ve the perception threshold. Hiccups appeared during inflation and res olved after deflation. Conclusions-Sudden rapid stretch of the mechano receptors in the proximal oesophagus can trigger the hiccup reflex in normal subjects. Only rapid distensions above a determined volume thre shold will predictably induce hiccups in a given subject. This mechani sm may play a role in the physiological induction of hiccups.