Abstract
Background: The diagnostic use of 24 hour oesophageal pH monitoring in infants is controversial because of the impact of feed buffering of gastric acidity.
Aim: To re-evaluate the effect of feeding on gastric pH and reflux using multipoint pH measurements.
Subjects: Fifteen healthy premature infants fed every four hours.
Methods: Oesophageal pH and intragastric pH at 3, 6, and 9 cm below the lower oesophageal sphincter were simultaneously measured using a four channel pH probe for four hours after bolus feeding. Parameters of pH were compared for the different levels within the stomach. During reflux episodes, the nadir pH was compared with intragastric pH at all levels.
Results: The proximal stomach was more significantly buffered by feeding and slower to re-acidify postprandially than the mid and distal stomach (42.2% of the time at pH < 4 compared with 58.7% and 55.7% respectively). During 27 of 62 gastro-oesophageal reflux episodes, nadir oesophageal pH was lower than the pH of the proximal stomach but always equal to or higher than the pH of the distal stomach.
Conclusions: These data indicate that previous studies may have overestimated the effect of feeding on gastric acidity and reflux.
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Figure 1 .
Schematic of the pH probe in situ. Sensors were located 12 cm (E1), 6 cm (G1), 3 cm (G2), and 0 cm (G3) from the tip. With the probe correctly positioned, E1 was located 3 cm above the lower oesophageal sphincter (LOS), and sensors G1, G2, and G3 were located 3, 6, and 9 cm below the LOS.
Figure 2 .
Median pH profiles recorded in the oesophagus and stomach at 3 cm (Gastric 1), 6 cm (Gastric 2), and 9 cm (Gastric 3) below the lower oesophageal sphincter in the 15 infants studied. Dotted lines represent the interquartile range.
Figure 3 .
Example tracing of intragastric pH recorded at the time of gastro-oesophageal reflux (GOR). Two reflux episodes are shown (shaded regions). During the first episode, oesophageal pH falls to a nadir that is lower than the pH recorded in the proximal stomach (G1) but greater than that in the mid and distal stomach (G2 and G3), suggesting that refluxate is originating from the mid and/or distal stomach. During the second reflux episode, expulsion of refluxate is followed by acidification of the proximal stomach indicating mixing of gastric contents.
Figure 4 .
Comparison of the mean basal and nadir pH during gastro-oesophageal reflux (GOR) episodes with regional intragastric pH. *Gastric pH significantly higher than nadir pH (***p < 0.005); †gastric pH significantly lower than nadir pH (†p < 0.05, ††p < 0.005, †††p < 0.0005).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
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