Development and validation of a gastroenterology probe capable of measuring the position of the squamo-columnar junction

The squamo-columnar junction is an important landmark in the upper gastro-oesophageal anatomy, acid reflux occurring above this causes heartburn and may lead to oesophageal cancer if prolonged. Currently no medical device takes into account the position of the squamo-columnar junction despite its importance. The aim of this doctoral work is to develop and validate a device which is capable of monitoring the position of the squamocolumnar junction with respect to simultaneous acid reflux and pressure measurements. Using Hall effect sensors on a custom flexible circuit board, and a magnet attached to the squamo-columnar junction, a device was produced which when inserted into the oesophagus, measured the relative position of the squamocolumnar junction to manometry and pH-metry catheters. The accuracy of the measurement was at most 5 millimetres, often better; a better resolution than either the high resolution manometer or custom pH device. The device was validated in-vivo, demonstrating a capability of measuring significant movement of the squamo-columnar junction during transient lower oesophageal sphincter relaxations. The accuracy of the high resolution manometer was tested, which showed significant drift, capable of causing misdiagnosis. A correction algorithm was produced which corrected linear drift, removing time dependant drift leading to significantly more accurate pressure readings. Catheter based upper gastro-oesophageal measurements have the potential to cause transient lower oesophageal sphincter relaxations by triggering mechanoreceptors in the pharynx; therefore a non-catheter based squamo-columnar junction locator was designed and tested. Using a larger magnet and significantly more sensitive Hall effect sensors and custom analogue circuitry, the squamo-columnar junction could be detected. The distance between the oesophagus and the skin is estimated to be between 8 and 9 centimetres for a healthy, non-obese male adult, the detection range for the non-catheter based squamo-columnar junction locator was 10.4 centimetres. The devices developed for this doctoral work has improved the field of gastroenterology research.

Name dc:type.qualificationname

engd

Level dc:type.qualificationlevel

doctoral-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2014

Author dc:creator

• Whiting, James Gerald Holland

DOI

10.48730/zwcx-8y13

Identifier

T13723

OAI identifier oai:identifier

oai:strathclyde:fb494846r