Differentiating esophageal sensitivity phenotypes using pH-impedance in intensive care unit infants referred for gastroesophageal reflux symptoms.

BACKGROUND

To identify esophageal sensitivity phenotypes relative to acid (SAcid), bolus (SBolus), acid and bolus (SAcid+Bolus), and none (SNone) exposures in infants suspected with gastroesophageal reflux disease (GERD).

METHODS

Symptomatic infants (N = 279) were evaluated for GERD at 42 (40-45) weeks postmenstrual age using 24-h pH-impedance. Symptom-associated probability (SAP) for acid and bolus components defined esophageal sensitivity: (1) SAcid as SAP ≥ 95% for acid (pH < 4), (2) SBolus as SAP ≥ 95% for bolus, (3) SAcid+Bolus as SAP ≥ 95% for acid and bolus, or (4) SNone as SAP < 95% for acid and bolus.

RESULTS

Esophageal sensitivity prevalence (SAcid, SBolus, SAcid+Bolus, SNone) was 28 (10%), 94 (34%), 65 (23%), and 92 (33%), respectively. Emesis occurred more in SBolus and SAcid+Bolus vs SNone (p < 0.05). Magnitude (#/day) of cough and emesis events increased with SBolus and SAcid+Bolus vs SNone (p < 0.05). SAcid+Bolus had increased acid exposure vs SNone (p < 0.05). Distributions of feeding and breathing methods were distinct in infants with SBolus vs SNone (both, p < 0.05). Multivariate analysis revealed that arching and irritability events/day were lesser at higher PMAs (p < 0.001) and greater for infants on NCPAP (p < 0.01) with SBolus and SAcid+Bolus (p < 0.05). Coughs/day was greater at higher PMAs (p < 0.001) for infants with gavage and transitional feeding methods (p < 0.02) with SBolus and SAcid+Bolus (p < 0.05) but lesser with Trach (p < 0.001). Number of emesis events/day were greater with SBolus and SAcid+Bolus (p < 0.001). Sneezes/day decreased for infants on Trach (p = 0.02).

CONCLUSIONS

Feeding and breathing methods can influence the frequency and type of aerodigestive symptoms. We differentiated esophageal sensitivity phenotypes in NICU infants referred for GERD symptoms using pH-impedance. Acid sensitivity alone was rare, which may explain poor response to acid suppressives; aerodigestive symptoms were predominantly linked with bolus spread. Magnitude of esophageal acid exposure and esophageal sensitivity to bolus spread may explain the pathophysiological basis for symptoms.

IMPACT: Objective GERD diagnosis and reasons for symptoms in NICU infants remains unclear. Differentiation of esophageal sensitivities by acid and bolus components of GER reveal distinct symptom profiles, specifically the bolus component of GER significantly contributes to symptom occurrence. Acid only sensitivity to GER is rare, and acid-suppressive therapy alone may not improve symptoms in a majority of NICU infants. Magnitude of esophageal acid exposure and esophageal sensitivity to any bolus spread may explain the pathophysiological basis for symptoms. Feeding and breathing methods can influence the frequency and type of aerodigestive symptoms. GERD treatments should be individualized to the patient's GERD phenotype and likely also target the bolus component of GER.