Intragastric pressure during food intake: a physiological and minimally invasive method to assess gastric accommodation.

BACKGROUND: The stomach relaxes upon food intake and thereby provides a reservoir while keeping the intragastric pressure (IGP) low. We set out to determine whether we could use IGP as a measurement for stomach accommodation during food intake.
METHODS: In fasted healthy volunteers (n = 7-17) a manometer and an infusion catheter were positioned in the proximal stomach. After a stabilization period a nutrient drink was intragastrically infused at 15, 30 and 60 mL min(-1). To investigate the effect of impaired accommodation the effect of N(G)-monomethyl-L-arginine (L-NMMA) was examined. The volunteers scored satiation until maximum, when the experiment ended. The IGP was presented as a change from baseline (mean ± SEM) and compared with repeated measures anova. KEY
RESULTS: Independent on the ingestion speed, the IGP decreased initially and gradually increased thereafter. Volunteers scored maximal satiation after 699 ± 62, 809 ± 90 and 997 ± 120 mL nutrient drink infused (15, 30 and 60 mL min(-1) respectively; P < 0.01). Maximum IGP decrease was 3.4 ± 0.5 mmHg after 205 ± 28 mL, 5.1 ± 0.7 mmHg after 212 ± 46 mL, and 5.2 ± 0.7 mmHg after 296 ± 28 mL infused volume [15, 30 and 60 mL min(-1) respectively; not significant (ns)]. Post hoc analysis showed significant correlations between IGP and satiation score increase. During L-NMMA infusion IGP was significantly increased while subjects drank significantly less (816 ± 91 vs 1032 ± 71 mL; P < 0.005). Interestingly, the correlation between IGP increase and satiation score increase did not differ after L-NMMA treatment. CONCLUSIONS & INFERENCES: The IGP during nutrient drink ingestion provides a minimally invasive alternative to the barostat for the assessment of gastric accommodation. These findings furthermore indicate that IGP is a major determinant of satiation.