Effect of Gaviscon Infant on gastro-oesophageal reflux in infants assessed by combined intraluminal impedance/pH

Abstract

Background: Gaviscon Infant (GI) has been recommended for gastro-oesophageal reflux (GOR) in infants. Its efficacy has not been examined with a physiologically appropriate denominator to define the degree of GOR.

Aim: To investigate the influence of Gaviscon Infant on GOR in infants using combined pH and intraluminal impedance measurement.

Methods: Twenty infants (mean age 163.5 days, range 34-319 days) exclusively bottle fed, with symptoms clinically suggestive of GOR, underwent 24 hour studies of intra-oesophageal 6 channel impedance and dual channel pH monitoring, during which six random administrations (3+3) of Gaviscon Infant (625 mg in 225 ml milk) or placebo (mannitol and Solvito N, 625 mg in 225 ml milk) were given in a double blind fashion. Impedance/pH reflux data were recorded and analysed blind by one observer.

Results: The median number of reflux events/hour (1.58 v 1.68), acid reflux events/hour (0.26 v 0.43), minimum distal or proximal pH, total acid clearance time per hour (time with pH below pH 4), and total reflux duration per hour were not significantly different after GI than after placebo. Reflux height was marginally lower after GI (median 66.6% v 77.3% oesophageal length) compared with placebo.

Conclusions: Results showed a marginal but significant difference between Gaviscon Infant and placebo in average reflux height, and raises questions regarding any perceived clinical benefit of its use.

Figure 1

Schematic representation of the impedance catheter with seven impedance electrodes set at 1.5 cm intervals and comprising six measuring segments (impedance channels). Distal and proximal pH electrodes were also incorporated to detect the pH of the refluxate at approximately 2 cm above the lower oesophageal sphincter (LOS) and in the upper oesophagus.

Figure 2

Impedance pattern typically observed during a reflux episode. In this example only the distal pH channel is shown which is located approximately 1.5 cm above the LOS. The retrograde oesophageal flow is indicated by arrow A. In this example the reflux reaches the proximal (highest, Z₁) channel. The reflux duration is indicated by arrow B. The pH of the reflux can be derived from the pH channel and the acid clearance is the time taken for the pH channel wave to reach pH 4.

Figure 3

After treatment with Gaviscon Infant, while the number of reflux events per hour was lower from 2 hours after feeding, compared with the first two hours after feeding, the difference in the number of reflux episodes per hour was not statistically significant. After treatment with placebo, the number of reflux events per hour was markedly lower from 2 hours after feeding, compared with the first two hours after feeding, and the difference was statistically significant (p < 0.001). pph, postprandial hour.