Am. J. Respir. Crit. Care Med.,
Volume 163, Number 5, April 2001, 1150-1152
Does Gastric Juice pH Influence Tonometric PCO2
Measured by Automated Air Tonometry?
ALEXANDER
BRINKMANN,
BERNHARD
GLASBRENNER,
ARNIM
VLATTEN,
HOLGER
EBERHARDT,
GÖTZ
GELDNER,
PETER
RADERMACHER,
MICHAEL
GEORGIEFF,
and
HEIDE
WIEDECK
Department of Anesthesiology and Internal Medicine, University Clinics Ulm, Ulm, Germany
To determine the influence of changes in gastric juice pH due to
intravenous administration of pentagastrin and omeprazole on intramucosal regional PCO2 (PrCO2), we investigated 17 healthy human volunteers. Gastric juice pH was obtained from a glass pH electrode for continuous gastric juice pH measurement and PrCO2
was measured by using automated air tonometry. After baseline
(8:00 A.M.-9:00 A.M.) the subjects received 0.6 µg/kg/h pentagastrin intravenously for 1 h (9:00 A.M.-10:00 A.M., after stimulation 10:00 A.M.-11:00 A.M.) and 40 mg omeprazole intravenously (after omeprazole 11:00 A.M.-3:00 P.M.). Following pentagastrin administration gastric juice pH significantly decreased from 1.2 ± 0.4 to
0.6 ± 0.4 (mean ± SD, p < 0.007, versus baseline), whereas omeprazole transiently increased luminal pH up to 4.4 ± 1.7 (p < 0.007 versus baseline). These subsequent changes in gastric juice
pH were accompanied by a significant increase in PrCO2 from 48 ± 12 to 61 ± 17 mm Hg (p < 0.007 versus baseline) and a decrease
to 44 ± 5 mm Hg (p < 0.002 versus pentagastrin), respectively. A
gastric juice pH > 4 considerably reduces mean gastric PrCO2 and
interindividual variability. Thus omeprazole may improve the validity of gastric tonometry data.
