Summary
The present study examines some of the assumptions underlying the use of intragastric pH-metry for assessing the degree of therapeutic gastric inhibition. Three separate studies were performed to determine the relationship between pH and titratable hydrogen ion concentration in gastric juice and to assess the relationship between the concentration of acid and the rate of gastric secretion. The concentration of acid derived from pH measurements tended to be lower than the titrated hydrogen ion concentration. The difference between the two readings — the “buffered” hydrogen ion concentration — was increased by the presence of food and was reduced during gastric secretory inhibition with ranitidine. The titrated hydrogen ion concentration reflected more accurately the amount of hydrochloric acid added to a container in vitro than pH measurement. However, in vivo even the measurement of titratable acidity was poorly correlated with the volume of secreted gastric juice so that measurement of gastric acid concentration does not permit inferences about the rate of gastric secretion. The results of the present study indicate that measurement of intragastric pH is unsatisfactory for assessing gastric secretion, particularly in response to a food stimulus, so that measurement of gastric acidity alone does not reflect the rate, or changes in the rate, of gastric acid secretion.
Similar content being viewed by others
References
Basson MD, Modlin IM (1987) Pepsinogen. Prolate ellipsoid or unrecognised pathogen? J Clin Gastroenterol 9:475–479
Burgett DW, Chiverton SG, Hunt RH (1990) Is there an optimal degree of acid suppression for healing of duodenal ulcer? A model of the relationship between ulcer healing and acid suppression. Gastroenterology 99:345–351
Dammann HG, Dreyer M, Kangah R, Wolf N (1990) Gastric aspiration technique for pH recording; a critical evaluation for this method. Dig Dis 8 [Suppl 1]: 3–9
Emde C (1990) Graphical display and statistical evaluation of data gained by long-term ambulatory intragastric pH monitoring. Dig Dis 8 [Suppl 1]: 87–96
Ernst TH, Zeyer B, Wilder-Smith C, Gennoni M, Röhmel J, Walt R, Halter F, Merki H (1989) Differentiation of cephalic and gastric secretion phases during H2-antagonist treatment. Gut 30:A734-A725
Feldman M (1979) Comparison of acid secretion rates measured by gastric aspiration and by in vivo intragastric titration in healthy human subjects. Gastroenterology 76:954–957
Fimmel CJ, Etienne A, Cillufo T, Ritter C, Gasser T, Rey JP, Caradonna-Moscatelli P, Sabbatini F, Pace F, Bühler HW, Bauerfeind P, Blum AL (1985) Longterm ambulatory gastric pH monitoring: validation of a new method and effect of H2 antagonists. Gastroenterology 88:1842–1851
Hunt JN, Knox MT (1972) The slowing of gastric emptying by four strong acids and three weak acids. J Physiol (Lond) 222:187–208
Johnston DA, Jankowski J, Penston JG, Wormsley KG (1989) Inhibition of nocturnal gastric secretion is not necessary for ulcer healing. Eur J Gastroenterol Hepatol 1:187–191
Kaufmann D, Wilder-Smith CH, Kempf M, Neumann J, Schmools H, Witzel L, Walt RP, Röhmel J, Merki HS (1990) Cigarette smoking, gastric acidity and peptic ulceration. What are the relationships? Dig Dis Sci 35:1482–1487
Lanzon-Miller S, Pounder RE, McIsaac RC, Wood JR (1990) The timing of the evening meal affects the pattern of 24-hour intragastric acidity. Aliment Pharmacol Ther 4:547–553
Makhlouf GM, Blum AC, Moore EW (1970) Undissociated activity of human gastric juice. Measurement and relationship to protein buffers. Gastroenterology 58:345–351
Merki HS, Witzel L, Walt RP, Neumann J, Scheurle E, Kaufmann D, Mappes A, Heim J, Röhmel J (1987) Comparison of ranitidine 300 mg twice daily, 300 mg at night and placebo as 24-hour intragastric acidity of duodenal ulcer patients. Aliment Pharmacol Ther 1:217–223
Merki HS, Fimmel CJ, Walt RP, Haare K, Röhmel J, Witzel L (1988) Pattern of 24 hour intragastric acidity in active duodenal ulcer disease and in healthy controls. Gut 29:1583–1587
Merki HS, Halter F, Wilder-Smith C, Allemann P, Witzel L, Kempf M, Röhmel J, Walt RP (1990) Effect of food on H2-receptor blockade in normal subjects and duodenal ulcer patients. Gut 31:148–150
Moore EW (1968) Determination of pH by the glass electrode; pH meter calibration for gastric analysis. Gastroenterology 54:501–507
Moore EW, Verine HJ, Grossman MI (1979) Pancreatic bicarbonate response to a meal. Acta Hepatol-Gastroenterol 26:30–36
Popiela T, Szafran Z, Szafran H, Komorowska M (1977) Relationship between undissociated acidity of gastric juice and gastric protein secreted in response to graded doses of pentagastrin in duodenal ulcer patients. Gut 18:208–213
Pounder RE, Fraser AG (1993) Gastric acid secretion and intragastric acidity: measurement in health and disease. In: Yeomans ND (ed) Inhibition of gastric acid secretion. Bailliere's Clinical Gastroenterology. Bailliere Tindall, London
Pounder RE, Sharma BK, Walt RP (1986) Twenty-four hour intragastric acidity during treatment with oral omeprazole. Scand J Gastroenterol 118 [Suppl]:108–117
Prewett EJ, Smith JTL, Nwokolo CU, Sawyer AM, Pounder RE (1991) Twenty-four hour intragastric acidity and plama gastrin concentration profiles in female and male subjects. Clin Sci 80:619–624
Rohmel J, Merki HS, Wilder-Smith CH, Walt RP (1990) Analysis and statistical evaluation of continuous pH recordings. Dig Dis 8 [Suppl 1]: 87–96
Savarino V, Mela GS, Scalabrini P, Sumberaz A, Fera G, Celle G (1988) 24 Hour study of intragastric acidity in duodenal ulcer patients and normal subjects using continuous intraluminal pH-metey. Dig Dis Sci 33:1077–1080
Wagner S, Gladziwa U, Gebel M, Schüler A, Freise J, Schmidt FW (1991) Circadian pattern of intragastric acidity in duodenal ulcer patients: a study of variations in relation to ulcer activity. Gut 32:1104–1109
Walt RP, Male PJ, Rawlings J, Hunt RH, Milton-Thomson GJ, Misiewicz JJ (1981) Comparison of the effect of ranitidine, cimetidine and placebo on the 24 hour intragastric acidity and nocturnal acid secretion in patients with duodenal ulcer. Gut 22:49–54
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Johnston, D.A., Wormsley, K.G. Problems with the interpretation of gastric pH measurement. Clin Investig 72, 12–17 (1993). https://doi.org/10.1007/BF00231110
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00231110