The pharmacological effect of omeprazole on water gastric emptying: A study based on an impedance measure

The present study was performed to validate the accuracy of a self-designed applied-potential tomograph (APT) in measuring the cross area of a studied object and to assess the effect of omeprazole premedication on water gastric emptying (GE), based on APT. Twelve electrodes were evenly placed in a circular array around the studied subjects. Ten electrodes in a rotated order recorded the electrical current injected into paired electrodes. Based on tomography, averaged signals of changed resistivity were constructed to display the area of interest and GE curve. Six beakers of various diameters were respectively placed into a cylindrical perspex tank which was filled with saline to measure their cross areas via computer-generated diagrams of APT. One hour after either omeprazole (20 mg) or placebo premedication, 15 healthy males were ordered to consume 500 ml of test water to assess emptying for 40 min. Within 3 days, a similar procedure was repeated using the counterpart premedication. The true cross areas of the 6 beakers are 2.01, 15.9, 18.8, 30.19, 38.48 and 63.61 cm(2), whereas those obtained by APT were 7.9 +/- 2.9, 16.7 +/- 3.3, 22.4 +/- 4.9, 28 +/- 4.8, 48.7 +/- 7.6 and 67 +/- 6.1 cm(2), respectively (r = 0.98, p < 0.001). Valid emptying data were obtained in 73.3 and 86.6% of subjects, following placebo and omeprazole, respectively (not significant). The half emptying times were 12.7 +/- 5.1 min for the placebo-treated group and 10.5 +/- 3.6 min for the omeprazole-treated group, respectively (p < 0.05). The areas under the emptying curve were 1,611.5 +/- 357.6 and 1,317.3 +/- 316.7 arbitrary units, respectively (p < 0.01). In conclusion, our APT system is accurate for large-area measurements; acid inhibition before APT measurement does not increase the success rate but enhances water emptying. The interpretation of impedance-obtained GE should consider the acid-inhibitory effect.