Characterizing Biomarkers of Continuous Peristalsis and Bolus Transit During Oral Feeding in Infants at pH-Impedance Evaluation: Clinical and Research Implications

Abstract

ObjectiveTo examine the biomarkers of pharyngoesophageal swallowing during oral feeding sessions in infants undergoing pH-impedance testing and determine if swallow frequencies are distinct between oral- and partially oral-fed infants. Study designOne oral feeding session was performed in 40 infants during pH-impedance studies and measurements included swallowing frequency, multiple swallow rate, air and liquid swallow rates, esophageal swallow clearance time (ESCT), and gastroesophageal reflux (GER) characteristics. Linear and mixed statistical models were applied to examine the swallowing markers and outcomes. ResultsInfants (30.2 ± 4.4 weeks birth gestation) were evaluated at 41.2 ± 0.4 weeks postmenstrual age (PMA). Overall, 10,675 swallows were analyzed during the oral feeding sessions (19.3 ± 5.4 min per infant) and GER events were noted (2.5 ± 0.3 per study). Twenty-four-hour acid reflux index (ARI) was 9.5 ± 2.0%. Differences were noted in oral- and partially oral-fed infants for: volume consumption (p<0.01), consumption rate (p<0.01), and length of hospital stay in days (p<0.01). Infants with ARI >7% had greater frequency of swallows (p=0.01). The oral-fed group had greater ARI (12.7 ± 3.3%, p=0.05). ConclusionsOropharyngeal swallowing regulatory characteristics decrease over the feeding duration and were different between ARI >7% vs ≤7%. Although GER is less in infants who are partially oral-fed, the neonates with increased acid exposure achieved greater oral intakes and shorter hospitalizations, despite the presence of comorbidities. Pharyngoesophageal stimulation as during consistent feeding or GER events can activate peristaltic responses and rhythms, which may be contributory to the findings.