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

OBJECTIVE: To examine the biomarkers of pharyngoesophageal swallowing during oral feeding sessions in infants undergoing pH-impedance testing and determine whether swallow frequencies are distinct between oral-fed and partially oral-fed infants. STUDY DESIGN: One 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, and gastroesophageal reflux (GER) characteristics. Linear and mixed statistical models were applied to examine the swallowing markers and outcomes. RESULTS: Infants (30.2 ± 4.4 weeks' birth gestation) were evaluated at 41.2 ± 0.4 weeks' postmenstrual age. Overall, 10 675 swallows were analyzed during the oral feeding sessions (19.3 ± 5.4 minutes 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-fed and partially oral-fed infants for volume consumption (P < .01), consumption rate (P < .01), and length of hospital stay in days (P < .01). Infants with ARI >7% had greater frequency of swallows (P = .01). The oral-fed group had greater ARI (12.7 ± 3.3%, P = .05). CONCLUSIONS: Oropharyngeal 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.

The Irritable Infant in the Neonatal Intensive Care Unit: Risk Factors and Biomarkers of Gastroesophageal Reflux Disease.

OBJECTIVES: To determine risk factors for arching/irritability in high-risk infants and examine the significance of comorbidity and gastroesophageal reflux (GER) characteristics. STUDY DESIGN: Retrospective analysis of 24-hour pH-impedance studies of symptomatic infants in a neonatal intensive care unit (ICU) (n = 516, 30.1 ± 4.5 weeks of gestation, evaluated at 41.7 ± 3.2 weeks postmenstrual age) was conducted. Comparisons were made between infants with >72 vs ≤72 arching/irritability events per day. We characterized risk factors for arching/irritability along with clinical, pH-impedance, and outcome correlates. RESULTS: Of 39 973 arching/irritability events and 42 155 GER events, the averages per day were 77.6 ± 41.0 and 81.7 ± 48.2, respectively. Acid reflux and impedance bolus characteristics were not significantly different between infants with >72 and ≤72 arching/irritability events (P ≥ .05). The odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for postmenstrual age and weight at evaluation were significant for risk factors of preterm birth (2.3 [1.2-4.4]), moderate or severe neuropathology (2.0 [1.1-3.6]), and presence of oral feeding at testing (1.57 [1.07-2.30]). CONCLUSIONS: Acid GER disease is unlikely the primary cause of arching/irritability and empiric treatment should not be used when arching/irritability is present. Prematurity and neurologic impairment may be more likely the cause of the arching/irritability. Arching/irritability may not be a concern in orally fed infants.