Impact of esophageal mucosal permeability markers on provocation‐induced esophageal reflexes in high‐risk infants

Esophageal distal baseline impedance (DBI) is an indicator of mucosal integrity; lower values suggest increased permeability. Aims were to characterize the (1) effect of DBI category (<900 Omega, 900-2000 Omega, and >2000 Omega) on sensory-motor characteristics of mid-esophageal provocation-induced motility reflexes, and (2) clinical outcomes among high-risk human infants evaluated for gastroesophageal reflux disease. Symptomatic infants (N = 49, 41 +/- 3 weeks postmenstrual age) underwent pH-impedance testing to characterize acid reflux index (ARI) and DIM, and pharyngo-esophageal manometry to examine upper esophageal sphincter (UES), peristaltic, and lower esophageal sphincter (LES) functions. Sensory-motor response characteristics included response threshold (ml), occurrence (%), latency (s), duration (s), and magnitude (mmHg) upon mid-esophageal stimulations (0.1-2.0 ml of air, water, and apple juice). Motility and clinical outcomes were compared among DBI groups. In infants with DBI <900 Omega and 900-2000 Omega (vs. >2000 Omega): (a) Long-term feeding milestones did not differ (p> 0.05); (b) complete peristaltic propagation decreased in 900-2000 Omega (p< 0.05), polymorphic waveforms increased in <900 Omega and 900-2000 Omega (p< 0.05); (c) media effects were noted with liquids (vs. air) wherein UES and esophageal contractility were prolonged in <900 Omega and 900-2000 Omega (p < 0.05), and esophageal sensitivity heightened for <900 Omega with water and for 900-2000 Omega with air (both p < 0.05). ARI was not correlated with DBI in infants with chronic lung disease (r = 0.05, p = 0.82). We conclude that pharyngo-esophageal motility sensory-motor characteristics in infants are modified by DBI category. These preliminary findings pave-the-way for further physiological testing in convalescing high-risk infants to ascertain potential mechanisms of airway-digestive reflex interactions and symptom generation, which may lead to targeted therapies.