title: Low intramucosal pH is associated with failure to acidify the gastric lumen in response to pentagastrin.
abstract: OBJECTIVE
  To determine if low gastric intramucosal pH is associated with impaired secretion of gastric acid after pentagastrin stimulation.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Intensive care unit of a university teaching hospital.
  
  
  METHODS
  20 patients requiring mechanical ventilation.
  
  
  METHODS
  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.
  
  
  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).
  
  
  CONCLUSIONS
  Some critically ill patients with low gastric intramucosal pH appear to have an impaired ability to acidify the gastric lumen in response to pentagastrin.
authors.affiliation: Bloomsbury Institute of Intensive Care Medicine, Middlesex Hospital, London, UK.
authors.forename: D
authors.initials: D
authors.lastname: Higgins
authors.forename: M G
authors.initials: MG
authors.lastname: Mythen
authors.forename: A R
authors.initials: AR
authors.lastname: Webb
mesh_terms: D000126:Achlorhydria / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D000368:Aged; D001784:Blood Gas Analysis; D016638:Critical Illness; D003428:Cross Infection / Q000453:epidemiology / Q000209:etiology; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D005753:Gastric Mucosa / Q000098:blood supply*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007362:Intensive Care Units; D007511:Ischemia / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010418:Pentagastrin; D011014:Pneumonia / Q000453:epidemiology / Q000209:etiology; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D015996:Survival Rate
chemical_list: D010418:Pentagastrin