Oesophageal Acid Exposure in Healthy Subjects Over 96 Hours
Condition: Gastroesophageal Reflux
MeSH terms: Gastroesophageal Reflux
Study type: Interventional

Summary: 
      First introduced over 40 years ago, the 24-hour catheter-based pH studies have previously
      been found to be the gold standard in the diagnosis of gastro-oesophageal reflux disease
      (GORD). In 2003, the Bravo has revolutionised the study of GORD, allowing patients an
      improved comfort and ability to perform activities of daily living.

      The backflow of gastric acid (acid exposure) in the oesophagus is monitored by a tiny pH
      sensor located in a capsule which is pinned temporarily to the wall of the oesophagus at the
      time of endoscopy. Normal measurements for acid exposure are established for 48-hour studies.
      However, the investigators' studies have shown that extending the duration of recording to 96
      hours further improved the diagnostic yield for GORD in patients with negative 24-hour
      catheter-based tests

      The 96-hour recording is the current standard of care, despite the lack of normal ranges for
      this duration of the recording. The basis for the diagnosis of GORD in 96-hours studies is
      based on the 48-hours normal controls. The objective of this study is to determine the normal
      values for oesophageal acid exposure using the wireless pH recording apparatus over 96 hours
      in asymptomatic healthy subjects with unrestricted activity and diet.
    

Detailed description: 
      This is a single centre study on healthy subjects to determine the normal values for
      oesophageal acid exposure using the wireless pH monitoring over 96 hours. The investigators
      anticipate the recruitment of 50 participants over 10 months.

      Subjects without reflux symptoms, either healthy volunteers (hospital staff and medical
      students) or people referred for gastroscopy in the context of other conditions (e.g. iron
      deficiency anaemia, suspected coeliac disease) will be recruited. An interview will be
      arranged where the subjects will be assessed for gastro-oesophageal symptoms using the
      Montreal GORD consensus definition and dysphagia based on the Hospital Odynophagia Dysphagia
      Questionnaire. Once confirmed asymptomatic, participants will be offered an appointment for
      enrolment. If candidates are asymptomatic, the subjects will be invited to a further
      interview where the procedure, risks and benefits will be discussed in detail. If
      participants fulfil the inclusion and exclusion criteria then participants will be given the
      option to enrol in the study. If at any point, participants wish to withdraw from the study,
      they have the option to do so without explaining why.

      Once recruited the following assessments and interventions will take place:

        1. Endoscopy and Bravo capsule placement under conscious sedation. The procedure will be
           performed by a trained endoscopist in using Bravo delivery system and dealing with any
           complications that may arise. Photographic documentation of capsule attachment will be
           taken.

        2. 96-hour pH monitoring. Study subjects will be asked to document food intake, periods of
           sleep and occurrence of symptoms in a diary. After 96 hours, participants will return to
           the Oesophageal Laboratory to hand back in the receivers and diaries. The data captured
           on the recorder during the procedure will be downloaded to a computer.

        3. Subjects will be offered a questionnaire detailing participants satisfaction with the
           overall study and an assessment of discomfort and interference with activities of daily
           living (diet, activity level) using a 5-point grading scale (1 = very
           unhappy/intolerant, 5 = very satisfied). A yes/no evaluation of participants ability to
           go to work or study on the day following the procedure and whether the participants
           would recommend this test to another person is also included.

        4. Data analysis will include the standard components of oesophageal pH monitoring - acid
           exposure, number and duration of reflux episodes over 96 hours and 72 hours.

        5. Statistical analysis will involve standard deviation, mean, median, 95th/5th percentiles
           and 25th/75th percentiles. Considering a 30% drop-out rate (the participants who cannot
           complete the test or their data is not useful), we will recruit 50 subjects to achieve
           35
    

Intervention name(s): Bravo
Intervention type(s): Device
Intervention description(s): wireless pH monitoring over 96 hours
Intervention model: Single Group Assignment
Intervention model description: healthy subjects and subjects referred for gastroscopy in context of other conditions
Masking: None (Open Label)
Primary purpose: Other