Duodenal pH dips as an index of transpyloric flow in conscious dogs.

BACKGROUND

To determine if duodenal pH fluctuations might be used as a valuable index of the occurrence of gastric chyme ejection, the transpyloric flow and pH in the duodenal bulb were monitored simultaneously in six dogs.

METHODS

Transpyloric flow, monitored by a chronically implanted electromagnetic flowmeter, was represented by individual pulses of flow. Relations between the volume of these flow pulses and changes in duodenal pH were assessed both postprandially and during the increased gastric outflow that followed gastric loading of buffered saline solutions at pH 2 and 4.

RESULTS

During fasting and gastric loading with buffered saline at pH 2, no consistent relationship between flow pulses and duodenal pH fluctuations was evident. After instillation of buffer solution at pH 4 and postprandially, the magnitude of duodenal pH fluctuations became proportional to the stroke volume of the flow pulses. The removal of bile from the proximal duodenum decreased the relationship.

CONCLUSIONS

It is concluded that duodenal pH measured at 2 cm from the pylorus might be used postprandially as an index of the transpyloric flow rate of chyme.