Multiple rapid swallowing: a complementary test during standard oesophageal manometry

Abstract  Multiple rapid swallowing (MRS) stimulates neural inhibition resulting in abolition of contractions in the oesophageal body (OB) and complete lower oesophageal sphincter (LOS) relaxation which is followed by peristalsis and LOS contraction. The aim of this study was to evaluate the yield of MRS to detect abnormalities in inhibitory or excitatory oesophageal mechanisms in patients with oesophageal symptoms and either normal standard manometry or ineffective oesophageal motility (IOM). MRS (five water swallows, 2 mL, separated by 2–3 s) was evaluated in 23 healthy subjects, 109 symptomatic patients with normal standard sleeve manometry and in 48 patients with IOM. Healthy subjects had complete inhibition of OB motility during MRS and a strong motor response after MRS, i.e. amplitude of OB contractions in the oesophageal body and LOS tone being higher than after single swallows. Almost 70% of patients with oesophageal symptoms and normal manometry had abnormal MRS, mainly consistent on inability to increase amplitude of OB contractions after MRS. Nearly, half of the patients with IOM were able to normalize OB contractions after MRS. MRS is a simple complementary test that can be added to standard oesophageal manometry. Two-thirds of patients with normal manometry show abnormal MRS that could potentially underlie their symptoms. A normal response to MRS in patients with severe IOM might be used to predict response to prokinetic treatment.     

Cardiovascular effects of gastric intubation and distension in healthy humans

Abstract  Few data exist on the effect of upper gut stimuli on the cardiovascular system. Aim of our study was to evaluate the cardiovascular effects of gastric intubation and distension. Eleven healthy subjects (eight men, aged 21–30 years) were studied and a non-invasive beat-to-beat cardiovascular monitoring system was used. After 15-min basal recording, a bag catheter was positioned in the proximal stomach and connected to a barostat. Recordings were first performed for 15 min with the bag deflated, then during inflation of air using a 100 mL per 2 min stepwise protocol until epigastric discomfort was reported, and finally for 15 min with the bag inflated at 75% of discomfort volume separed from the preceding period by 10 min with the bag deflated. Presence of the deflated bag catheter significantly increased mean arterial pressure. Stepwise distension progressively increased heart rate and cardiac index, while mean arterial pressure was affected only at discomfort volume. Peripheral resistances and systemic plasma catecholamines were unaffected. During prolonged distension, the effect on heart rate and cardiac index was transient. In conclusion, both gastric intubation and distension alter cardiovascular parameters, but the effect of distension undergoes rapid adaptation. Experimentally induced gastric distension is a valuable stimulus to study viscero-cardiovascular reflexes and their mechanisms using beat-to-beat measurements.