The aim of this study was to determine how much acid exposure would occur in the proximal esophagus, both in normal and in patients with abnormal distal esophageal acid exposure.

Fourty-six patients with suspected GER were classified into two groups, 24 patients with pathological distal reflux (group II); 22 patients with normal distal reflux(group II). The ambulatory dual-probe esophageal pH monitoring was performed for 18-24hr. The abnormal reflux was defined when the percent of time that pH was below 4.0 exceeded the 95th percentile of normal value.

The siginficant differences between distal and proximal esophageal pH recordings in group I persisted for all parameters except for the longest episode, but didn't persist in group II. At the distal esophageal site, the median percent time with pH<4.0 in group I was 19.3 and significantly higher than at proximal site. Half of patients with pathological distal reflux also had proximal acid reflux. Correlation coefficients between the distal and proximal esophageal sites in group I of the number of reflux episodes and time of the longest episode were 0.451 and 0.646 respectively.

The 50 percent of patients with pathological distal acid reflux also had abnormal acid exposure in the proximal esophageal site. Therefore, we recommand simultaneous pH recordings from dual probe esophageal sites in children with gastroesophageal reflux.