Introduction Recently prolonged catheter-free pH monitoring (Bravo^®, Given Imaging, Yoqeam, Israel) up to 96 hours has become possible which enables more physiological evaluation of oesophageal acid exposure and its response to therapeutic interventions. This study applied this technology to measure acid reflux, and reflux related symptoms in patients with proven gastro-oesophageal reflux disease on and off high-dose PPIs. The potential utility of this methodology in guiding medical therapy was assessed.

Methods Patients with reflux symptoms were recruited prospectively from Mar.2012 to Oct.2012. PPI was stopped for 7 days prior to the Bravo capsule insertion. The 1st 48hr pH recording was performed off PPI and the 2nd 48hr was on twice daily PPI. The 48hr pH and symptom data for the two periods were compared, including percentages of acid exposure in total, upright and supine periods and symptom–reflux association for which heartburn (HB), chest pain (CP) and regurgitation (RG) were analysed. Data were expressed as median & interquartile. Wilcoxon signed-rank and Mann Whitney tests were used for statistical analysis (*P < 0.05; **P < 0.01; *** < 0.001).

Results Data from prolonged pH monitoring up to 96 hours were available from 89patients of whom 36 (22 males, mean age 50, range 26–76 years old) with complete studies and pathological acid exposure in the 1st 48 hours were studied in detail. Acid reflux measurements on PPI therapy were greatly reduced when compared to those recorded off therapy (Table). 27/36 (75%) patients had normal acid exposure on PPI therapy. The overall number of HB and CP reported in the 2nd 48hr period was reduced by almost two thirds (13 (4–26) vs.5 (2–14)**); however the number of these symptoms that were actually associated with acid reflux events was almost completely abolished (4 (2–14) vs.1 (0–3)***). No effect on volume RG was present.

Conclusion Sequential 48hrs recording off/on PPI therapy using Bravo pH test is feasible in routine clinical practise. This technique documents the physiological and clinical response to PPI therapy on acid reflux and acid reflux associated symptoms (i.e. heartburn, chest pain). These preliminary findings suggest that this methodology could be of value in distinguishing symptoms related to acid reflux that respond to acid suppression and guiding medical therapy in reflux disease.

Disclosure of Interest None Declared