pH Monitoring in the Distal and Proximal Esophagus in Symptomatic Infants *Alvaro Arana, *Beatrice Bagucka, *Bruno Hauser, *Badriul Hegar, †Daniel Urbain, ‡Leonard Kaufman, and *Yvan Vandenplas *Department of Pediatrics, †Department of Gastroenterology, ‡Department of Biostatistics, Free University of Brussels, Brussels, Belgium ABSTRACT Background: Standard distal esophageal pH monitoring data are sometimes within normal ranges in children with clinically suspected gastroesophageal reflux disease. Therefore, the au- thors hypothesized that the amount of acid reflux reaching the proximal esophagus may be greater in some subgroups of pa- tients than in healthy controls or in other subgroups of patients. Methods: The parameters of 24-hour pH monitoring in the proximal part of the esophagus were analyzed in 120 symp- tomatic infants in who the reflux parameters in the lower esophagus were clearly within normal ranges (reflux index < 5.0%). The infants were classified into four patient groups: excessive regurgitation (n  41); inconsolable crying (n  31), apparent life- threatening event (ALTE) (n  18), and chronic respiratory disorders (n  30). The control group con- sisted also of 120 infants. The following parameters were cal- culated: reflux index, the number of reflux episodes, the num- ber of reflux episodes lasting longer than 5 minutes, the dura- tion of the longest reflux episode, and the acid clearance time (ACT, duration of reflux episodes divided by number of reflux episodes). Results: The patients with chronic respiratory disorders were significantly older than the patients in the other groups and the controls. In the distal esophagus, there was no statistically sig- nificant difference between the reflux parameters. As could be expected, every parameter was statistically (paired t test, Wil- coxon signed-rank test) significantly smaller in the proximal than in the distal esophagus, except for the ACT in infants who presented with inconsolable crying. In the proximal esophagus, there was no statistically significant difference between the different patient subgroups or controls, except for the number of reflux episodes in the group with chronic respiratory disor- ders and the group with inconsolable crying, applying one-way analysis of variance. As determined by applying the Mann- Whitney test, the number of reflux episodes in the upper esophagus was significantly higher in the group with chronic respiratory disorders than in the other patient groups and con- trols. Therefore, the authors’ data do not support the hypothesis that reflux reaching the proximal esophagus is a frequent cause of ALTE. However, the data may suggest that the number of reflux episodes reaching the proximal esophagus in children with chronic respiratory disorders and with distal pH monitor- ing data within normal ranges may be increased. Whether this finding reflects reality or a statistical coincidence, or is influ- enced by the older age of this patient group, needs further evaluation. Conclusions: In theory, dual simultaneous esophageal pH monitoring in the distal and proximal esophagus may increase the diagnostic accuracy of pH monitoring in infants. Our results do not support a substantial advantage of a systematic applica- tion of this new technique, especially not in infants presenting with ALTE, excessive regurgitation, or inconsolable crying. In the subgroup of patients with chronic respiratory disorders, more data are needed before conclusions can be determined and recommendations can be made. JPGN 32:259–264, 2001. Key Words: Gastroesophageal reflux—pH monitoring—pH me- try—Pharangeal pH monitoring. © 2001 Lippincott Williams & Wilkins, Inc. Gastroesophageal reflux (GER) is a physiologic phe- nomenon that occurs in every infant. Clinical manifesta- tions of GER disease cover a broad spectrum of mani- festations, such as excessive regurgitation and vomiting, chronic respiratory disease (chronic respiratory disor- ders), inconsolable crying, and apparent life-threatening events (ALTE) (1). Twenty-four–hour esophageal pH monitoring is considered to be the reference investiga- tion to detect and quantify acid GER episodes and to separate physiologic from pathologic acid reflux (1). Standard distal esophageal pH monitoring evaluates the incidence and duration of acid reflux episodes in the lower to middle part of the esophagus (2). Normal ranges were developed to separate physiologic from pathologic GER in premature and term infants with a history of Received March 17, 2000; accepted November 29, 2000. Address correspondence and reprint requests to Dr. Yvan Vandenplas, Academisch Ziekenhuis VUB, Laarbeeklaan 101, 1090 Brussels, Bel- gium (e-mail: yvan.vandenplas@az.vub.ac.be). Journal of Pediatric Gastroenterology and Nutrition 32:259–264 © March 2001 Lippincott Williams & Wilkins, Inc., Philadelphia 259