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Updated: Oct 7, 2026

Simultaneous Laryngopharyngeal and Conventional Esophageal pH Monitoring
Published on: December 14, 2020
Low intramucosal pH is associated with failure to acidify the gastric lumen in response to pentagastrin
D Higgins1, M G Mythen, A R Webb
1Bloomsbury Institute of Intensive Care Medicine, Middlesex Hospital, London, UK.
Objective:
To determine if low gastric intramucosal pH is associated with impaired secretion of gastric acid after pentagastrin stimulation.
Design:
Prospective study.
Setting:
Intensive care unit of a university teaching hospital.
Patients:
20 patients requiring mechanical ventilation.
Interventions:
All patients with a gastric luminal pH > 4 were given pentagastrin 6 micrograms/kg s.c. to stimulate gastric acid secretion and the response assessed by further measurements of gastric luminal pH.
Measurements And Results:
Gastric intramucosal pH (pHi) and luminal pH (pHL) were measured. Patients were divided into two groups on the basis of a low or normal pHi (A value of 7.35 was taken as the lower limit of normal). Patients (n = 6) with normal pHi (7.40 +/- 0.05 [mean +/- SD]) and a luminal pH > 4 (5.65 +/- 1.25) all had a decrease in pHL in response to pentagastrin (decrease in pHL 4.02 +/- 1.52). Of the patients (n = 7) with low pHi (7.2 +/- 0.13) and a pHL > 4 (6.51 +/- 0.48) only one responded to pentagastrin (decrease in pHL for this group 0.93 +/- 1.86). Patients with a pHL < 4 (2.4 +/- 0.71) were not given pentagastrin (n = 7).
Conclusion:
Some critically ill patients with low gastric intramucosal pH appear to have an impaired ability to acidify the gastric lumen in response to pentagastrin.
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