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Measurement of gastric bicarbonate secretion in the human stomach: different methods produce discordant results.
Scand J Gastroenterol. 1992 Oct; 27(10):829-36.SJ

Abstract

Human gastric bicarbonate secretion has been measured by back-titration, from pH and pressure of carbon dioxide (PCO2) determinations (using the Henderson-Hasselbalch formula), and from equations based on gastric juice osmolality and [H+] (osmolality-[H+] method). Since these methods show large quantitative differences in their estimations of gastric bicarbonate secretion, we examined each to define the reasons for these discrepancies and establish guidelines for future work in this area. Bicarbonate recovery from 'non-parietal' secretions (0 to 80 mM HCO3) reacting with 'pure parietal secretion' (160 mM HCl) was studied both in vitro and in the pylorus-occluded healthy human stomach during acid suppression, exogenous acidification, and pentagastrin stimulation. The pH/PCO2 method estimated HCO3- accurately under anaerobic conditions in vitro, whereas the osmolality-[H+] method (with correction factors for osmolality incorporated by us) was accurate under aerobic conditions. In the acid-suppressed stomach back-titration was significantly more accurate than the pH/PCO2 method. In the exogenously acidified and pentagastrin-stimulated stomachs the pH/PCO2 method underestimated bicarbonates, and the osmolality-[H+] method was spuriously elevated in the low range and diminished at high bicarbonate concentrations. Estimates of 'basal' bicarbonate secretion (at zero added bicarbonate) were severalfold higher by the osmolality-[H+] method (5.26 +/- 0.33 mmol/h) than by the pH/PCO2 method (1.20 +/- 0.23 mmol/h) or back-titration (0.65 +/- 0.14 mmol/h). In conclusion, gastric bicarbonate was determined most correctly by back-titration in the acid-suppressed stomach, whereas measurement of bicarbonate in the acid-secreting stomach was not accurate with any method.

Authors+Show Affiliations

Odes HS
Dept. of Medicine, UCSD Medical Center.
Hogan DL
No affiliation info available
Steinbach JH
No affiliation info available
Ballesteros MA
No affiliation info available
Koss MA
No affiliation info available
Isenberg JI
No affiliation info available

MeSH

AdultBicarbonatesCarbon DioxideEvaluation Studies as TopicFemaleGastric Acidity DeterminationGastric JuiceHumansHydrogen-Ion ConcentrationMaleOsmolar ConcentrationPentagastrinSodiumSodium Bicarbonate

Pub Type(s)

Journal Article

Language

eng

PubMed ID

1332183

Citation

Odes, H S., et al. "Measurement of Gastric Bicarbonate Secretion in the Human Stomach: Different Methods Produce Discordant Results." Scandinavian Journal of Gastroenterology, vol. 27, no. 10, 1992, pp. 829-36.
Odes HS, Hogan DL, Steinbach JH, et al. Measurement of gastric bicarbonate secretion in the human stomach: different methods produce discordant results. Scand J Gastroenterol. 1992;27(10):829-36.
Odes, H. S., Hogan, D. L., Steinbach, J. H., Ballesteros, M. A., Koss, M. A., & Isenberg, J. I. (1992). Measurement of gastric bicarbonate secretion in the human stomach: different methods produce discordant results. Scandinavian Journal of Gastroenterology, 27(10), 829-36.
Odes HS, et al. Measurement of Gastric Bicarbonate Secretion in the Human Stomach: Different Methods Produce Discordant Results. Scand J Gastroenterol. 1992;27(10):829-36. PubMed PMID: 1332183.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Measurement of gastric bicarbonate secretion in the human stomach: different methods produce discordant results. AU - Odes,H S, AU - Hogan,D L, AU - Steinbach,J H, AU - Ballesteros,M A, AU - Koss,M A, AU - Isenberg,J I, PY - 1992/10/1/pubmed PY - 1992/10/1/medline PY - 1992/10/1/entrez SP - 829 EP - 36 JF - Scandinavian journal of gastroenterology JO - Scand J Gastroenterol VL - 27 IS - 10 N2 - Human gastric bicarbonate secretion has been measured by back-titration, from pH and pressure of carbon dioxide (PCO2) determinations (using the Henderson-Hasselbalch formula), and from equations based on gastric juice osmolality and [H+] (osmolality-[H+] method). Since these methods show large quantitative differences in their estimations of gastric bicarbonate secretion, we examined each to define the reasons for these discrepancies and establish guidelines for future work in this area. Bicarbonate recovery from 'non-parietal' secretions (0 to 80 mM HCO3) reacting with 'pure parietal secretion' (160 mM HCl) was studied both in vitro and in the pylorus-occluded healthy human stomach during acid suppression, exogenous acidification, and pentagastrin stimulation. The pH/PCO2 method estimated HCO3- accurately under anaerobic conditions in vitro, whereas the osmolality-[H+] method (with correction factors for osmolality incorporated by us) was accurate under aerobic conditions. In the acid-suppressed stomach back-titration was significantly more accurate than the pH/PCO2 method. In the exogenously acidified and pentagastrin-stimulated stomachs the pH/PCO2 method underestimated bicarbonates, and the osmolality-[H+] method was spuriously elevated in the low range and diminished at high bicarbonate concentrations. Estimates of 'basal' bicarbonate secretion (at zero added bicarbonate) were severalfold higher by the osmolality-[H+] method (5.26 +/- 0.33 mmol/h) than by the pH/PCO2 method (1.20 +/- 0.23 mmol/h) or back-titration (0.65 +/- 0.14 mmol/h). In conclusion, gastric bicarbonate was determined most correctly by back-titration in the acid-suppressed stomach, whereas measurement of bicarbonate in the acid-secreting stomach was not accurate with any method. SN - 0036-5521 UR - https://www.unboundmedicine.com/medline/citation/1332183/Measurement_of_gastric_bicarbonate_secretion_in_the_human_stomach:_different_methods_produce_discordant_results_ DB - PRIME DP - Unbound Medicine ER -