Gastric tonometry in healthy volunteers: effect of ranitidine on calculated intramural pH
Document Type
Journal ArticlePublication Date
1991-02-01Keywords
*Gastric Acidity DeterminationHumans
Methods
Ranitidine
Anesthesiology
Heterocyclic Compounds
Pharmaceutical Preparations
Therapeutics
Metadata
Show full item recordAbstract
OBJECTIVE: To determine if intraluminal production of CO2 leads to underestimation of gastric intramural pH (pHi) by tonometry. DESIGN: Nonrandomized controlled study. PATIENTS: Healthy volunteers. INTERVENTIONS: NG tonometers were placed in healthy volunteers. Some of the volunteers (n = 11) were pretreated with ranitidine to prevent secretion of protons into the gastric lumen. Others (n = 13) were untreated (i.e., gastric acid secretion was uninhibited). MEASUREMENTS AND MAIN RESULTS: Gastric pHi was calculated from the arterial (HCO3-) and the tonometrically determined intraluminal PCO2 using the Henderson-Hasselbalch equation. Intraluminal PCO2 was significantly higher in the control group (54 +/- 14 torr [7.2 +/- 1.9 kPa]) than in the ranitidine-treated group (42 +/- 4 torr [5.6 +/- 0.4 kPa], p = .02). Mean gastric luminal pH was 1.9 +/- 0.6 in the control group as compared with 6.7 +/- 0.7 in volunteers treated with ranitidine (p less than .01). Mean calculated gastric pHi was 7.30 +/- 0.11 in the untreated group and 7.39 +/- 0.03 in the ranitidine-treated group (p less than .03). CONCLUSIONS: These data suggest that intraluminal production of CO2 from the titration of gastric HCO3- by secreted H+ can result in the underestimation of gastric pHi by tonometry. This phenomenon can be eliminated by H2-receptor blockade.Source
Crit Care Med. 1991 Feb;19(2):271-4.
DOI
10.1097/00003246-199102000-00025Permanent Link to this Item
http://hdl.handle.net/20.500.14038/25799PubMed ID
1989762Related Resources
ae974a485f413a2113503eed53cd6c53
10.1097/00003246-199102000-00025