title: Effect of nasogastric suction and ranitidine on the calculated gastric intramucosal pH.
abstract: OBJECTIVE
  To study the effect of nasogastric suction and ranitidine on the determination of gastric intramucosal pH (pHi).
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Clinical research unit at a university hospital intensive care department.
  
  
  METHODS
  12 healthy volunteers.
  
  
  METHODS
  After a 2-h measurement control period a tonometer was connected to nasogastric suction for 2 h, and thereafter ranitidine was given intravenously and gastric pHi measured.
  
  
  RESULTS
  During each 2-h measurement period gastric PCO2, gastric pHi, and pH gap were determined every 30 min. Luminal pH was measured after insertion of tonometer and at the end of each study period. Neither nasogastric suction nor ranitidine had an effect on the coefficient of variation for either gastric PCO2 or pHi. Compared to control and nasogastric suction periods, after ranitidine mean gastric pHi was higher (control 7.22 +/- 0.08; nasogastric suction 7.23 +/- 0.07; after ranitidine 7.31 +/- 0.06, p < 0.001) mean gastric PCO2 lower (control 6.4 +/- 1.3; nasogastric suction 6.5 +/- 1.3; after ranitidine 5.3 +/- 0.9, p < 0.001) and pH gap lower (control 0.18 +/- 0.08; nasogastric suction 0.17 +/- 0.05; after ranitidine 0.09 +/- 0.06, p < 0.01). Luminal pH increased after ranitidine in each subject.
  
  
  CONCLUSIONS
  H2 blockers have no effect on the reproducibility of gastric pHi measurements, but the use of H2 blockers modifies the normal values for gastric pHi in healthy subjects.
authors.affiliation: Department of Intensive Care, Kuopio University Hospital, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Parviainen
authors.forename: O
authors.initials: O
authors.lastname: Vaisänen
authors.forename: E
authors.initials: E
authors.lastname: Ruokonen
authors.forename: J
authors.initials: J
authors.lastname: Takala
mesh_terms: D000328:Adult; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D005745:Gastric Acidity Determination; D005753:Gastric Mucosa / Q000737:chemistry* / Q000378:metabolism; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D011446:Prospective Studies; D011899:Ranitidine; D013396:Suction / Q000009:adverse effects*
chemical_list: D006635:Histamine H2 Antagonists; D011899:Ranitidine