The effect of pH change on the gastric emptying of liquids measured by electrical impedance tomography and pH-sensitive radiotelemetry capsule.

Citrate phosphate buffer liquid adjusted to different pH values was used to investigate the gastric emptying profiles in human using simultaneous monitoring by electrical impedance tomography (EIT) and pH sensitive radiotelemetry capsule. No interference was observed between the two methods during data acquisition periods. A positive correlation between methods from the pooled data was demonstrated. Statistical moments analysis demonstrated a significant delay in the onset of gastric emptying and also the mean gastric residence time of the pH 3 buffer liquid (34.7-46.7 min) when compared with pH 7 buffer liquid (14.4-22.5 min). These data suggest that the negative feedback gastrin related response to acidity of the liquid was high. However, incorporation of an acid suppression compound (ranitidine), as part of the control study showed that the EIT imaging of this buffer could be successfully performed under normal physiological conditions. When 450 ml pH 7 buffer liquid was measured, no significant difference in gastric emptying rate was observed. This study demonstrated that, citrate phosphate buffers can be used as an alternative test liquid for EIT monitoring, and that pH has a systematic effect on gastric emptying and the lag phase.