Gastro-Oesophageal Reflux and Apnoea: Is There a Temporal Relationship?

Effects of Nasal Respiratory Support on Laryngeal and Esophageal Reflexes in Preterm Lambs

BACKGROUND

Significant cardiorespiratory events can be triggered in preterm infants as part of laryngeal chemoreflexes (LCRs) and esophageal reflexes (ERs). We previously showed that nasal continuous positive airway pressure (nCPAP) blunted the cardiorespiratory inhibition induced with LCRs. Therefore, we aimed to compare the effects of nCPAP and high-flow nasal cannulas (HFNC) on the cardiorespiratory events induced during LCRs and ERs. The hypothesis is that nCPAP but not HFNC decreases the cardiorespiratory inhibition observed during LCRs and ERs.

METHODS

Eleven preterm lambs were instrumented to record respiration, ECG, oxygenation, and states of alertness. LCRs and ERs were induced during non-rapid eye movement sleep in a random order under these conditions: nCPAP 6 cmH2O, HFNC 7 L/min, high-flow nasal cannulas 7 L/min at a tracheal pressure of 6 cmH2O, and no respiratory support.

RESULTS

nCPAP 6 cmH2O decreased the cardiorespiratory inhibition induced with LCRs, but not with ERs in preterm lambs. This blunting effect was less marked with HFNC 7 L/min, even when the tracheal pressure was maintained at 6 cmH2O.

CONCLUSIONS

nCPAP might be a treatment for cardiorespiratory events related to LCRs in newborns, either in the context of laryngopharyngeal refluxes or swallowing immaturity. Our preclinical results merit to be confirmed through clinical studies.

IMPACT

Laryngeal chemoreflexes can be responsible for significant cardiorespiratory inhibition in newborns, especially preterm. Nasal continuous positive airway pressure at 6 cmH2O significantly decreased this cardiorespiratory inhibition. High-flow nasal cannulas at 7 L/min had a lesser effect than nasal continuous positive airway pressure. Esophageal stimulation was responsible for a smaller cardiorespiratory inhibition, which was not significantly modified by nasal continuous positive airway pressure or high-flow nasal cannulas. Nasal continuous positive airway pressure should be tested for its beneficial effect on cardiorespiratory events related to laryngeal chemoreflexes in preterm newborns.

Continuous versus bolus intermittent intragastric tube feeding for preterm and low birth weight infants with gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease is a particularly common condition among preterm and low birth weight infants. These infants are more likely to have excessive regurgitation, as they do not have a fully developed antireflux mechanism. Preterm and low birth weight infants who are unable to suck oral feeds are required to be fed via an intragastric tube for varying lengths of time. Intragastric tube feeding can be delivered by the intermittent bolus method or by the continuous feeding method. Use of continuous or intermittent bolus intragastric feeding may have a positive or negative effect on the incidence or severity of gastro-oesophageal reflux disease.

OBJECTIVES

• To determine whether continuous or intermittent bolus intragastric tube feeding reduces the number of episodes and the duration of gastro-oesophageal reflux disease (GORD) in preterm and low birth weight infants • To perform subgroup analyses for gestational age; birth weight; age in days from birth at full enteral feeding via intragastric tube (breast versus bottle); frequency of intermittent bolus feed; and type of medication for treatment of GORD (only if medication was prescribed and was given similarly to both intervention groups) SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 7), in the Cochrane Library; Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions(R); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), on 8 July 2020. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

Published and unpublished RCTs and quasi-RCTs were eligible for inclusion in this review, as were cluster-randomised and cross-over randomised trials that compared the effects of continuous versus intermittent bolus intragastric tube feeding on gastro-oesophageal reflux disease in preterm and low birth weight infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and quality. We planned to use the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We found no trials that met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

We did not identify any randomised trials that evaluated the effects of continuous versus intermittent bolus intragastric tube feeding on gastro-oesophageal reflux disease in preterm and low birth weight infants. Well-designed and adequately powered trials are needed.

The Role of Combined Multichannel Intraluminal Impedance-pH Monitoring in Infants with Brief, Resolved, Unexplained Events

PURPOSE

Data on the relationship between gastroesophageal reflux (GER) and brief resolved unexplained events (BRUE) in infants is scarce. The aim of this study was to identify the characteristics of combined multichannel intraluminal impedance-pH (MII-pH) monitoring in infants who have experienced BRUE.

METHODS

We conducted a prospective study of infants who were hospitalized on account of BRUE and required 24-hour MII-pH monitoring.

RESULTS

Twenty-one infants (mean age, 4.7 months; range, 0.9-8.9 months; male/female, 11/10) participated in this study. BRUE symptoms associated with GER were found in 10 infants (47.6%). Based on the RI on pH-metry alone, only 7 (33.3%) infants were diagnosed with GERD. More than 100 GER episodes detected by MII were found in 10 (47.6%) infants. Nineteen percent of infants were diagnosed with GERD based on both pH and MII.

CONCLUSION

Both acid and non-acid reflux seem to play a significant role in the pathogenesis of GER-related BRUE in infants.

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 (S_Acid), bolus (S_Bolus), acid and bolus (S_Acid+Bolus), and none (S_None) 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) S_Acid as SAP ≥ 95% for acid (pH < 4), (2) S_Bolus as SAP ≥ 95% for bolus, (3) S_Acid+Bolus as SAP ≥ 95% for acid and bolus, or (4) S_None as SAP < 95% for acid and bolus.

RESULTS

Esophageal sensitivity prevalence (S_Acid, S_Bolus, S_Acid+Bolus, S_None) was 28 (10%), 94 (34%), 65 (23%), and 92 (33%), respectively. Emesis occurred more in S_Bolus and S_Acid+Bolus vs S_None (p < 0.05). Magnitude (#/day) of cough and emesis events increased with S_Bolus and S_Acid+Bolus vs S_None (p < 0.05). S_Acid+Bolus had increased acid exposure vs S_None (p < 0.05). Distributions of feeding and breathing methods were distinct in infants with S_Bolus vs S_None (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 S_Bolus and S_Acid+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 S_Bolus and S_Acid+Bolus (p < 0.05) but lesser with Trach (p < 0.001). Number of emesis events/day were greater with S_Bolus and S_Acid+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.

Feeding and Swallowing Difficulties in Neonates: Developmental Physiology and Pathophysiology

Development of enteral and oral feeding milestones in infants is intricately linked to physiologic maturation of the gastrointestinal tract and its complex interplay with cardiorespiratory and central nervous system control and coordination. Assessment of an infant's developmental skills and maturation can guide us with targeted management approaches and prediction of feeding outcomes. In this article, we review and summarize the developmental aspects of oral feeding and swallowing physiology, and current understanding of the pathophysiological changes associated with feeding difficulties in infants.

Gastroesophageal Reflux Disease in the Neonatal Intensive Care Unit Neonate: Controversies, Current Understanding, and Future Directions

Gastroesophageal reflux (GER) is considered physiologic and is a normal process; whereas, when aerodigestive consequences are associated, it is often interpreted as GER disease (GERD). However, the distinction between them remains a challenge in infants in the NICU. Reflux-type of symptoms are heterogeneous, and often managed with changes in diet, feeding methods, and acid-suppressive therapy; all these empiric therapies lack objectivity; hence, practice variation is universal. We clarify the current controversies, explain the potential role of GERD in causing symptoms and complications, and highlight current advances. The evidence basis for the diagnostic strategies is discussed.

Assessment and Management of Gastroesophageal Reflux in The Newborn

Gastroesophageal reflux is the involuntary retrograde passage of gastric contents into the esophagus with or without regurgitation and is considered a normal physiologic process, occurring daily in greater than one-third of all infants. Gastroesophageal reflux disease (GERD) is pathologic reflux associated with poor weight gain, irritability, dysphagia and often requires evaluation and treatment. No gold-standard testing for GERD exists. Measurements made by pH probe or multichannel intraesophageal impedance may provide insight into the quantity and character of reflux. Those events do not correlate well with clinical symptoms. Most cases of GERD can be treated conservatively with alterations in the infant's environment and/or feeding pattern. Proton pump inhibitors remain the mainstay for pharmacotherapy of GERD, although these have been associated with increased rates of infection, especially in the preterm population. Neonatal GERD remains a difficult entity to define and manage, and additional studies to aid in the clinical diagnosis and management are needed. [Pediatr Ann. 2020;49(2):e77-e81.].

Immunonutrition for Preterm Infants

Care and outcomes for very preterm infants continue to improve, but important causes of mortality and acute and long-term morbidity associated with prolonged hospitalisation remain. Necrotising enterocolitis (NEC) and late-onset infection have emerged as the major causes of death beyond the early neonatal period and of neurodisability in very preterm infants. Although the pathogenesis of these conditions is incompletely understood, it appears to be related to the content and mode of delivery of the enteral diet, particularly the impact of immunonutrients from human breast milk on the microbial and metabolic balance within the immature intestine. Evidence exists to support investment in measures to help mothers to express breast milk as the primary source of nutrition for their very preterm infants. In the absence of maternal milk, pasteurised donor breast milk provides protection against NEC, but its nutritive adequacy is not clear and its cost-effectiveness is uncertain. Supplementation with individual immunonutrients, including immunoglobulins and lactoferrin, has not been shown to be effective in preventing NEC or infection in randomised controlled trials. The evidence base for prebiotics and probiotics is stronger, but concerns exist about the choice, safety and availability of formulations. Other strategies - including avoidance of drugs such as gastric acid suppressants that compromise innate immunity, as well as evidence-based progressive feeding strategies that reduce exposure to invasive interventions - are emerging as key components of care packages to reduce the burden of NEC, infection and associated growth and developmental faltering for very preterm infants.

Detection of gastro-oesophageal reflux in the neonatal unit

AIM

To determine whether a pH probe or multichannel intraluminal impedance (MII) more frequently detected gastro-oesophageal reflux and test the hypothesis that acid reflux was associated with lower baseline impedance.

METHODS

A prospective study of infants in whom reflux was suspected and evaluated using combined pH and multichannel impedance. Studies were considered abnormal if the acid index was >10% or there were >79MII reflux events in 24 hours. The acid index was the percentage of total study time with a pH

RESULTS

Forty-two infants [median gestational age 31 (range 23-42) weeks] were assessed. Only nine infants (21%) had abnormal studies, seven detected by pH monitoring, one by MII monitoring and one by both techniques (p = 0.04). After correcting for gestational age and post-natal age, baseline impedance remained negatively correlated with the acid index (r = -0.34, p = 0.038) and the maximum ACT (r = -0.44, p = 0.006).

CONCLUSION

Clinical suspicion of reflux was frequently incorrect, and reflux was more frequently detected by a pH probe. The inverse relationship of acid reflux to baseline impedance suggests that mucosal disruption may result from acid reflux in this population.

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Key Words

• Baseline oesophageal impedance
• Multichannel intraluminal impedance
• pH study

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Affiliation(s)

Thomas Rossor MRC Centre in Allergic Mechanisms of Asthma, King's College London, London, UK Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
Ingran Lingam Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, London, UK
Abdel Douiri Department of Primary Care and Public Health Sciences, King's College London, London, UK NIHR Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust, King's College London, London, UK
Ravindra Bhat Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, London, UK
Anne Greenough MRC Centre in Allergic Mechanisms of Asthma, King's College London, London, UK Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK NIHR Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust, King's College London, London, UK

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