Development and apllication of an ambulatory esophageal manometry system
Date
2016-08-19
Authors
Bremner, Ross Macrae
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Abstract
The aim of this project was to develop an automated system capable of
monitoring intraesophageal pressures for prolonged periods of time, and to evaluate the
clinical relevance of this system. Stationary esophageal manometry is, at present, the
cornerstone of assessing esophageal motor function. it's shortcomings, related to the
brevity of the test and the unphysiologic environment in which it is performed, have
limited our understanding of esophageal motility abnormalities. The goal of this study
was to overcome these shortcomings.
The thesis first describes the development of the hardware and software required
to continuously monitor, and then analyze, pressures and pH from the esophagus in the
ambulatory individual over a 24-hour period. Validation of the automated analysis and
establishment of normal values are then described. The system was then used to
evaluate patients with functional esophageal disorders in the esophageal laboratory at the
University of Southern California (USC), Los Angeles.
Many patients with gastroesophageal reflux disease were found to have a
profound motility defect of the esophageal body as evidenced by an inability to improve
propulsive function during meals. This defect was not apparent on stationary
manometry and has important implications for anti-reflux surgery. The increased
sensitivity of ambulatory manometry in detecting poor motor function is now being used
to tailor surgery in those requiring operative repair at USC.
Patients with primary esophageal motor disorders such as diffuse esophageal
spasm, achalasia, nutcracker esophagus and hypertensive lower esophageal sphincter
were found to have many overlapping features whick inspired a new classlfication based
on discussed.
The added advantage of combining a PH probe with the pressure manometer is
the ability to dectect clearance mechanisms in normal subjects and patients with
gastroesophageal reflux disease. The ability to record pharyngeal pressures using this
system demonstrated the importance of pharyngeal induced peristalsis in clearing the
esophagus of refluxed acid. Clearance mechanisms were found to be related to the state
of consciousness and provided an explanation for the severe mucosal complications seen
in patients with excessive nocturnal reflux. The clearance mechanisms of patients with
Barrett's esophagus were shown to be compromised because of an alteration in the
sensitivity of the columnar mucosal feedback mechanisms resulting in delayed and
phlegmatic pharyngeal swallowing after the onset of a reflux episode.
This thesis describes the new insights afforded by ambulatory manometry and the
benefits of having this intormation prior to instituting therapy in patients with esophageal
disorders. The developed system can be performed with little added discomfort to the
patient undergoing pH monitoring. It is hoped that the ease of performing the test and
the added insight provided by the study will encourage the use of ambulatory manometry
as the gold-standard for evaluating esophageal motor disorders.
Description
A dissertation Submitted to the Faculty of Medicine
University of the Witwatersrand, Johannesburg
For the Degree of Doctor of Philosophy (Medicine).
Johannesburg and Los Angeles, 1997