Measurementofgastrointestinal pHprofiles innormal ambulant humansubjects

SUMMARY Gastrointestinal (GI)pHhasbeenmeasured in66normal subjects using apHsensitive radiotelemetry capsule passing freely through thegastrointestinal tract. Signals were recorded with a portable solid state receiver andrecording system, enabling unconstrained measurements with normal ambulatory activities for up to48hduring normal GItransit. Capsule position inthegutwas monitored bysurface location using a directional detector. Gastric pH was highly acidic (range 10-2.5) inall subjects. Themean pHintheproximal small intestine was 6.6(0.5) forthefirst hourof intestinal recording. Bycomparison themean pHintheterminal ileum was 7.5(0.4) (p<0001). In all subjects there was asharpfall inpHtoamean of6.4(04)(p<0.001) asthecapsule passed into the caecum. Values aremeans (SD). pHthenroseprogressively fromtheright totheleft colon witha final mean value of7.0(0.7) (p<0001).