Continuous computerized determination of gastric bicarbonate secretion in man

Area of Science:

• Gastroenterology
• Physiology
• Biomedical Engineering

Background:

• Gastric bicarbonate secretion plays a vital role in protecting the stomach lining.
• Accurate and continuous measurement methods are essential for physiological and pharmacological studies.
• Existing methods may lack the precision or continuous monitoring capabilities needed.

Purpose of the Study:

• To develop and validate a computer-based system for continuous determination of gastric bicarbonate secretion in humans.
• To assess the system's ability to identify duodenogastric reflux and account for salivary contamination.
• To evaluate the impact of prostaglandin E2 on gastric bicarbonate output.

Main Methods:

• A computer system continuously recorded gastric pH and Pco2 to calculate bicarbonate secretion every 30 seconds.
• High gastric perfusion rates were used to detect duodenogastric reflux.
• Continuous salivary suction and amylase correction minimized salivary bicarbonate contribution.
• System validation involved introducing known amounts of bicarbonate into the stomach.

Main Results:

• The system demonstrated high accuracy, with a correlation of 0.91 (p < 0.001) between added and recovered bicarbonate.
• Basal gastric bicarbonate output in healthy subjects was 379 ± 105 μmol/h.
• Intragastric prostaglandin E2 administration resulted in a fourfold increase in gastric bicarbonate output.

Conclusions:

• The developed system provides a reliable and continuous method for measuring human gastric bicarbonate secretion.
• This technology allows for precise physiological measurements and assessment of gastric mucosal defense mechanisms.
• The findings highlight the significant stimulatory effect of prostaglandin E2 on gastric bicarbonate secretion.