The Effect of Position on Oesophageal Peristalsis and LOS Pressures: a High Resolution Manometry Study

Introduction High Resolution Manometry (HRM) is an advance in oesophageal measurement that permits the acquisition of pressure data through the entire length of the oesophagus over time via closely spaced sensors that continuously record the motor activity of the oesophagus. This information can then be analysed either as conventional line plots or as a spatiotemporal plot, a compact, visually intuitive presentation of oesophageal pressure activity.1 This process has been quantified and verified in 75 normal volunteers.2 Increasing evidence suggests that HRM is a more sensitive and accurate means of assessing oesophageal function compared to conventional manometry.1 3 Compared to conventional manometry, HRM increases the accuracy with which the success of bolus transport can be predicted.1 This is important because oesophageal symptoms are more closely linked to impaired bolus transport than conventional pressure measurements per se.4

The additional information provided by HRM and the presentation of data as a spatiotemporal plot enable investigators to study the pressure activity in the oesophagus during normal eating behaviour for the first time. This study will assess the effects of position, bolus volume and consistency (liquid, solid). In addition, pressure activity during a standardized test meal will be observed.

Understanding the oesophageal response due to these 'physiologic challenges' is likely to be of clinical importance because most patients complain of swallowing problems, regurgitation or chest pain during such events and in the postprandial period. This is in contrast to standard manometry protocols that include the intake only of individual water, viscous fluid (e.g. yoghurt) or small, solid bolus swallows.

Healthy controls will be studies to provide normal data. Patients referred for investigation of oesophageal symptoms will be studied to assess whether physiologic challenge increases the ability to differentiate this group from normal controls, explain patient symptoms and increase diagnostic yield.

Effects of Position It is well known that transient lower oesophageal sphincter relaxations (TLOSRs) and reflux events are suppressed in the supine position in both healthy volunteers and in patients with mild-moderate reflux disease.7 The effects of position on oesophageal peristalsis and lower oesophageal sphincter pressure assessed by conventional manometry have been less consistent.