Correlation between gastric pH and gastro‐oesophageal reflux contents: ambulatory pH‐impedance monitoring results

Abstract

Gastro-oesophageal reflux events should be related to gastric contents. The goal of this study was to determine the relationship between gastric pH and the nature of reflux events. Ambulatory oesophageal pH-impedance and gastric pH monitoring was performed in 41 patients [29 off and 12 on proton pump inhibitor (PPI) therapy] and 12 controls. The mean gastric pH was measured within 2 min around the reflux episodes, 10 cm below the cardia. Acid reflux events occurred more frequently at gastric pH <4 (89%) than non-acid reflux events (63%, P < 0.0001). Acid reflux events extended more frequently 15 cm above the lower oesophageal sphincter (LOS; 34%) than non-acid reflux episodes (24%, P = 0.005). Gastric pH was significantly lower during interprandial reflux events than during postprandial ones in the three groups (P < 0.001). A positive correlation was found between gastric pH and the nadir oesophageal pH during reflux events in the three groups: this correlation was more significant in patients on PPI therapy. We conclude that most acid and non-acid reflux episodes occur at acid gastric pH, as measured 10 cm below the LOS. This measure does not appear a good predictor of the pH of reflux events.

Weakly acidic refluxes have a major role in the pathogenesis of proton pump inhibitor‐resistant reflux oesophagitis

“…However, the OAET and the number of acid refluxes were above the normal range only in 20% and 25% of cases respectively: these findings are to be related to the lack of correlation between GAET and OAET ( r s = 0.072, P = N.S. ), in accordance with previous studies, 13, 18 and confirm the multi‐factorial pathogenesis of GERD.…”

Reflux patterns in patients with short‐segment Barrett’s oesophagus: a study using impedance‐pH monitoring off and on proton pump inhibitor therapy

“…The PPI regimen adopted in this study was highly effective in suppressing heartburn as well as oesophageal acid exposure. There was no significant correlation between the OAET and the GAET on PPI therapy, confirming that the latter is not a good predictor of the pH of reflux events 36 …”

Normal values of 24-hour ambulatory esophageal impedance-pH monitoring in a rural South African cohort of healthy participants

“…In healthy subjects, gastric pH depends on acid secretion and foodstuff ingested. Controversially, Roman et al . demonstrated that weakly alkaline reflux can occur despite gastric pH measured in the fundus being acid.…”

“…In healthy subjects, gastric pH depends on acid secretion and foodstuff ingested. Controversially, Roman et al 10 demonstrated that weakly alkaline reflux can occur despite gastric pH measured in the fundus being acid. This could be explained by a burst of weakly alkaline gastric contents from the lower part of the stomach going through the acid layer present at the fundus.…”