Traditional vs wireless intragastric pH monitoring : are the two techniques comparable?

Background.  Few data are available comparing intragastric pH measured with the traditional catheter-based and the more recent wireless system (Bravo), and also comparing intraesophageal and intragastric pH during reflux events. Aims of our study were to elucidate these points. Methods  Eleven subjects with functional dyspepsia underwent placement of a Bravo capsule 9 cm below the squamo-columnar junction (SCJ) and of a dual-electrode catheter, so that the distal electrode was located 9 cm below and the proximal one 6 cm above the SCJ. Key Results  The wireless system showed lower intragastric pH than the traditional catheter in the postprandial period (median 2.2 wireless vs 2.7 catheter, P < 0.05) but not in the whole 24 h. Moreover, during the 24 h, minimum intraesophageal pH during reflux events was lower than the simultaneous pH in the gastric body recorded using the catheter (2.2 vs 2.4, P < 0.01) and in the postprandial period lower than the one recorded using both techniques (2.3 vs 2.8 wireless and 3.2 catheter, P < 0.001). Conclusions & Inferences  (i) after meals, in the 1st 2 h postprandial pH in the gastric body is significantly lower when measured with the wireless capsule than with the traditional catheter, presumably because of less buffering by food in proximity of the mucosa, (ii) during reflux events intraesophageal pH is lower than pH in the gastric body, in accordance with the notion of greater intragastric acidity in the subcardial region.