Global State of the Art and Science of Childhood Dysphagia: Similarities and Disparities in Burden

Feeding/swallowing and airway protection are complex functions, essential for survival, and continue to evolve throughout the lifetime. Medical and surgical advances across the globe have improved the long-term survival of medically complex children at the cost of increasing comorbidities, including dysfunctional swallowing (dysphagia). Dysphagia is prominent in children with histories of preterm birth, neurologic and neuromuscular diagnoses, developmental delays, and aerodigestive disorders; and is associated with medical, health, and neurodevelopmental problems; and long-term socioeconomic, caregiver, health system, and social burdens. Despite these survival and population trends, data on global prevalence of childhood dysphagia and associated burdens are limited, and practice variations are common. This article reviews current global population and resource-dependent influences on current trends for children with dysphagia, disparities in the availability and access to specialized multidisciplinary care, and potential impacts on burdens. A patient example will illustrate some questions to be considered and decision-making options in relation to age and development, availability and accessibility to resources, as well as diverse cultures and family values. Precise recognition of feeding/swallowing disorders and follow-up intervention are enhanced by awareness and knowledge of global disparities in resources. Initiatives are needed, which address geographic and economic barriers to providing optimal care to children with dysphagia.

Proton pump inhibitor therapy may alter the sensory motor characteristics of pharyngoesophageal motility in infants with suspected GERD

BACKGROUND

Acid reflux index (ARI) is a biomarker for gastroesophageal reflux disease (GERD). The effects of short-term proton pump inhibitor (PPI) therapy on pharyngoesophageal motility and clearance mechanisms in infants remain unknown. We hypothesized that pharyngoesophageal reflexes and response to PPI are distinct between infants with 3%-7% and >7% ARI.

METHODS

Secondary analysis was performed from a subset of infants who participated in a randomized controlled trial (NCT: 02486263). Infants (N = 36, 29.9 ± 4.3 weeks gestation) underwent 4 weeks of PPI therapy, 1 week of washout, and longitudinal testing to assess: (a) clinical outcomes; (b) pH-impedance and symptom metrics including ARI, distal baseline impedance, clearance time, refluxate height, symptoms, I-GERQ-R scores, symptom association probability; (c) pharyngoesophageal motility reflexes and sensory motor characteristics. Comparisons were performed between infants with 3%-7% versus >7% ARI.

KEY RESULTS

From the 36 hospitalized infants treated: Pharyngoesophageal reflex latencies were prolonged (p > 0.05) and duration in ARI 3%-7% group only (p = 0.01); GER frequency, proximal ascent and clearance increased (ARI 3%-7%); weight gain velocity, oral feeding success, and fine motor score decreased while length of hospital stays increased in the ARI >7% group despite the decrease in symptoms and I-GERQ-R scores.

CONCLUSIONS & INFERENCES

Distinct changes in pharyngoesophageal sensory motor aspects of motility and reflex mechanisms exist after using PPI therapy in infants. Contributory factors may include the effects of maturation and aerodigestive comorbidities (GERD and BPD). Controlled studies incorporating placebo are needed to delineate the effects of PPI on causal and adaptive GERD mechanisms in infants with aerodigestive and feeding-related comorbidities.

Characteristics of esophageal refluxate and symptoms in infants compared between pre-treatment and on treatment with proton pump inhibitors

OBJECTIVE

To examine longitudinal pH-impedance characteristics from those infants who remained on proton pump inhibitors therapy for gastroesophageal reflux disease (GERD) as parents/providers refused to discontinue therapy after 4 weeks.

STUDY DESIGN

Eighteen infants with acid reflux index >3% underwent treatment, and pH-impedance data were compared prior to and on proton pump inhibitors at 42 ± 1 and 46 ± 1 weeks' postmenstrual age, respectively. Esophageal acid and bolus exposure, symptoms and swallowing characteristics were examined.

RESULTS

Proton pump inhibitors reduces the acid-mediated effects of reflux but modifies impedance and clearance mechanisms (P < 0.05). Prolonged therapy did not reduce symptoms (P > 0.05). Infants evaluated while on proton pump inhibitors were 1.8 times more likely to have swallows before and after reflux.

CONCLUSIONS

Prescription of proton pump inhibitors for objectively determined GERD should have time limits, as prolonged treatment can result in prolonged esophageal bolus clearance time without relieving symptoms.

Comparison of direct effects of rice-thickened formula vs routine feeds on symptoms and gastroesophageal reflux indices: A crossover cohort study

BACKGROUND

We compared the direct effects of routine vs rice-thickened formula on 24-h pH-impedance and symptom characteristics and then examined if dietary effects were modified by acid reflux index severity in infants.

METHODS

Forty infants under consideration for gastroesophageal reflux disease and therapies were evaluated at 43 ± 1 weeks postmenstrual age. Each infant was equally fed routine diet and thickened formula during evaluations. Postprandial sessions were analyzed for acid reflux index, reflux events, clearance times, distal baseline impedance, and symptoms.

RESULTS

Thickened formula has no effect (P ≥ 0.05) on acid reflux events' characteristics or overall symptom frequency. However, refluxate height and frequency of weakly acidic events and cough were decreased (P < 0.05). Prolonged bolus clearance and a decrease in distal baseline impedance were noted with thickened feeds (vs routine feeds) when acid reflux index was >7 (P < 0.05).

CONCLUSION

Our pH-impedance testing protocol identifies direct effects of potential therapies at the point of care. Acutely, thickened formula does not impact acid-specific reflux indices but decreases full-column reflux and cough reflexes. In those with an acid reflux index of >7, thickened formula prolongs the distal esophageal bolus clearance (the mechanisms of which are uncertain). Clinical trials are needed to clarify objective indications and therapeutic use of thickened formulas for infants with gastroesophageal reflux disease, along with short- and long-term side effects.

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.

A decade of evidence: standardized feeding initiative targeting feeding milestones and predicting NICU stays in premature infants in an all-referral level IV NICU

OBJECTIVE

Ten-year data from the simplified, individualized, milestone-targeted, pragmatic, longitudinal and educational (SIMPLE) feeding initiative were examined by gestational age (GA) category to characterize the feeding milestones, length of hospital stays (LOHS), annual variability and predictive models for LOHS.

STUDY DESIGN

Preterm infants (≤32 weeks GA, N = 434) in level-IV NICU had milestone-targeted feeding plans. Continuous data were analyzed for outcomes.

RESULTS

Over 93% successfully attained full oral feedings. Earlier acquisition of feeding milestones correlated with earlier discharge (P < 0.05). Year-wise analysis showed sustained maintenance of milestones (P < 0.05). Milestones and outcomes (P < 0.001) were significantly correlated with different GA categories. Prediction models for LOHS were derived using GA, BPD, age at full enteral, postmenstrual age (PMA) at 1st and full oral feeds.

CONCLUSIONS

The SIMPLE feeding program minimized variability and promoted acquisition of feeding milestones consistently. LOHS is predictable using feeding milestones, co-morbidities, GA, and PMA at feeding milestones.

Pharyngeal biorhythms during oral milk challenge in high-risk infants: Do they predict chronic tube feeding?

BACKGROUND

Eating difficulties are common in high-risk neonatal intensive care unit (NICU) infants; mechanisms remain unclear. Crib-side pharyngo-esophageal motility testing is utilized to assess contiguous swallowing physiology, and cross-system interplay with cardio-respiratory rhythms. Aims were to: (1) identify whether distinct pharyngeal rhythms exist during oral milk challenge (OMC), and (2) develop a chronic tube feeding risk prediction model in high-risk infants.

METHODS

Symptomatic NICU infants (N = 56, 29.7 ± 3.7 weeks birth gestation) underwent pharyngo-esophageal manometry with OMC at 40.9 ± 2.5 weeks postmenstrual age (PMA). Exploratory cluster data analysis (partitioning around k-medoids) was performed to identify patient groups using pharyngeal contractile rhythm data (solitary swallows and swallows within bursts). Subsequently, (a) pharyngeal-esophageal, cardio-respiratory, and eating method characteristics were compared among patient groups using linear mixed models, and (b) chronic tube feeding prediction model was created using linear regression.

RESULTS

Three distinct patient groups were identified with validity score of 0.6, and termed sparse (high frequency of solitary swallows), intermediate, or robust (high swallow rate within bursts). Robust group infants had: lesser pharyngeal and esophageal variability, greater deglutition apnea, pharyngeal activity, and esophageal activity (all p < 0.05), but less frequent heart rate decreases (p < 0.05) with improved clinical outcomes (milk transfer rate, p < 0.001, and independent oral feeding at discharge, p < 0.03). Chronic tube feeding risk = -11.37 + (0.22 × PMA) + (-0.73 × bronchopulmonary dysplasia) + (1.46 × intermediate group) + (2.57 × sparse group).

CONCLUSIONS

Robust pharyngeal rhythm may be an ideal neurosensorimotor biomarker of independent oral feeding. Differential maturation of cranial nerve-mediated excitatory and inhibitory components involving foregut, airway, and cardiac rhythms distinguishes the physiologic and pathophysiologic basis of swallowing and cardio-respiratory adaptation.

Symptom Scores and pH-Impedance: Secondary Analysis of a Randomized Controlled Trial in Infants Treated for Gastroesophageal Reflux

BACKGROUND AND AIMS

To evaluate and compare gastro-esophageal reflux (GER) symptom scores with pH-impedance and test the effects of acid-suppressive medications with or without feeding modifications on pH-impedance in high-risk infants.

METHODS

Infant Gastroesophageal Reflux Questionnaire Revised (I-GERQ-R) and 24-hour pH-impedance data were analyzed from 94 infants evaluated in a tertiary care setting for GER disease. Longitudinal data from 40 infants that received randomized GER therapy (proton pump inhibitor [PPI] with or without feeding modifications) for 4 weeks followed by 1-week washout were analyzed. Relationships between I-GERQ-R and pH-impedance metrics (acid reflux index, acid and bolus GER events, distal baseline impedance, and symptoms) were examined and effects of treatments compared.

RESULTS

(A) Correlations between I-GERQ-R and pH-impedance metrics were weak. (B) I-GERQ-R sensitivity, specificity, and positive predictive values were suboptimal when correlated with pH-impedance metrics. I-GERQ-R negative predictive value (NPV) was high for acid symptom-association probability (NPV = 84%) and distal baseline impedence (NPV = 86%) thresholds. (C) PPI with feeding modifications (vs PPI alone) did not alter pH-impedance metrics or symptom scores (P > .05); however, bolus clearance metrics worsened for both treatment groups (P < .05).

CONCLUSIONS

In high-risk infants (1) I-GERQ-R may be a helpful clinical screening tool to exclude acid-GER disease diagnosis and minimize unnecessary acid-suppressive treatment, but further testing is needed for diagnosis. (2) Acid-suppressive therapy with feeding modifications has no effect on symptom scores or pH-impedance metrics. Clearance of refluxate worsened despite PPI therapy, which may signal development of pharyngoesophageal dysmotility and persistence of symptoms. (3) Placebo-controlled trials are needed in high-risk infants with objective pH-impedance criteria to determine efficacy, safety, and underlying mechanisms. Clinicaltrials.gov ID: NCT02486263.

Evidence-Based Approaches to Successful Oral Feeding in Infants with Feeding Difficulties

Infants in the neonatal intensive care unit (NICU) frequently have feeding difficulties with the root cause remaining elusive to identify. Evaluation of the provider/parent/infant feeding process may provide objective clues to sources of feeding difficulty. Specialized testing may be necessary to determine if the infant's swallowing skills are dysfunctional, immature, or maldeveloped, and to determine the risk of feeding failure or chronic tube feeding. Current evidence-based diagnostic and management approaches resulting in successful oral feeding in the NICU infant are discussed.

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 Ω, 900-2000 Ω, and >2000 Ω) 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 DBI, 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 Ω and 900-2000 Ω (vs. >2000 Ω): (a) Long-term feeding milestones did not differ (p > 0.05); (b) complete peristaltic propagation decreased in 900-2000 Ω (p < 0.05), polymorphic waveforms increased in <900 Ω and 900-2000 Ω (p < 0.05); (c) media effects were noted with liquids (vs. air) wherein UES and esophageal contractility were prolonged in <900 Ω and 900-2000 Ω (p < 0.05), and esophageal sensitivity heightened for <900 Ω with water and for 900-2000 Ω 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.

Developing a Quality Improvement Feeding Program for NICU Patients

Practices in NICUs vary widely, particularly when clinical decisions involve complex tasks and multiple disciplines, which occurs with feeding preterm infants. Neonatal feeding difficulties in preterm infants often lead to prolonged tube feeding and therefore lengthened hospital stays. Education and compliance with evidence-based protocols and guidelines are needed on the initiation of feedings and feeding advancement to transform enteral and oral feeding practices and thus reduce practice variation and improve clinical outcomes.

Mechanisms and management considerations of parent-chosen feeding approaches to infants with swallowing difficulties: an observational study

Videofluoroscopy swallow studies (VFSS) and high-resolution manometry (HRM) methods complement to ascertain mechanisms of infant feeding difficulties. We hypothesized that: (a) an integrated approach (study: parent-preferred feeding therapy based on VFSS and HRM) is superior to the standard-of-care (control: provider-prescribed feeding therapy based on VFSS), and (b) motility characteristics are distinct in infants with penetration or aspiration defined as penetration-aspiration scale (PAS) score ≥ 2. Feeding therapies were nipple flow, fluid thickness, or no modification. Clinical outcomes were oral-feeding success (primary), length of hospital stay and growth velocity. Basal and adaptive HRM motility characteristics were analyzed for study infants. Oral feeding success was 85% [76-94%] in study (N = 60) vs. 63% [50-77%] in control (N = 49), p = 0.008. Hospital-stay and growth velocity did not differ between approaches or PAS ≥ 2 (all P > 0.05). In study infants with PAS ≥ 2, motility metrics differed for increased deglutition apnea during interphase (p = 0.02), symptoms with pharyngeal stimulation (p = 0.02) and decreased distal esophageal contractility (p = 0.004) with barium. In conclusion, an integrated approach with parent-preferred therapy based on mechanistic understanding of VFSS and HRM metrics improves oral feeding outcomes despite the evidence of penetration or aspiration. Implementation of new knowledge of physiology of swallowing and airway protection may be contributory to our findings.

Pharyngoesophageal motility reflex mechanisms in the human neonate: importance of integrative cross-systems physiology

Swallowing is a critical function for survival and development in human neonates and requires cross-system coordination between neurological, airway, and digestive motility systems. Development of pharyngoesophageal motility is influenced by intra- and extrauterine development, pregnancy complications, and neonatal comorbidities. The primary role of these motility reflex mechanisms is to maintain aerodigestive homeostasis under basal and adaptive biological conditions including oral feeding, gastroesophageal reflux, and sleep. Failure may result in feeding difficulties, airway compromise, dysphagia, aspiration syndromes, and chronic eating difficulties requiring prolonged tube feeding. We review the integration of cross-systems physiology to describe the basis for physiological and pathophysiological neonatal aerodigestive functions.

Prophylactic Indomethacin in extremely preterm infants: association with death or BPD and observed early serum creatinine levels

OBJECTIVES

To identify the relationship between prophylactic indomethacin (PI) administration and (1) mortality and bronchopulmonary dysplasia (BPD) at 36-week postmenstrual age (PMA) (primary outcome), and (2) to evaluate for PI-associated acute kidney injury.

STUDY DESIGN

Retrospective cohort investigation of 22-28 weeks gestation infants (N = 1167) who were admitted to Nationwide Children's Hospital on postnatal days 0-1 between May 2009 and September 2017 and survived ≥24-h postnatal. The associations of PI treatment with mortality or BPD, and other secondary outcomes, were evaluated via multivariable robust-error-variance Poisson regression.

RESULTS

The adjusted risks of death or BPD (1.02, 95% CI: 0.83, 1.25), BPD (0.97, 95% CI: 0.77, 1.21), and death 1.33 (95% CI: 0.84, 2.10) by 36-week PMA were unchanged following PI treatment after multivariable adjustment. No changes in mean creatinine levels were detected in exposed versus unexposed infants to suggest PI-induced AKI.

CONCLUSION

Prophylactic indomethacin treatment was unrelated to mortality or BPD outcomes.

Impact of Feeding Strategies With Acid Suppression on Esophageal Reflexes in Human Neonates With Gastroesophageal Reflux Disease: A Single-Blinded Randomized Clinical Trial

INTRODUCTION

Aims were to test hypothesis that esophageal provocation-induced reflexes are superior with acid suppression plus feeding modifications vs acid suppression alone among infants treated for gastroesophageal reflux disease (GERD).

METHODS

Infants (N = 49, 41.3 ± 2.6 of postmenstrual age) with acid reflux index >3% underwent longitudinal motility testing (weeks 0 and 5) with graded midesophageal provocation to test randomly allocated therapies (4 weeks' proton pump inhibitor [PPI] ± feeding modifications) on sensory-motor aerodigestive reflexes. Feeding modification included restricted fluid volume <140 mL/kg per day, fed over 30 minutes in right lateral position and supine postprandial position. Primary motility outcome was frequency-occurrence of peristaltic reflex. Secondary outcomes included upper esophageal sphincter contractile reflex, lower esophageal sphincter (LES) relaxation reflex, respiratory change, and symptom characteristics.

RESULTS

Treatment groups did not differ for primary outcome (odds ratio = 0.8, 95% confidence interval 0.4-1.6, P = 0.99) or secondary outcomes (all P > 0.05). For both treatment groups at follow-up, distal esophageal contraction and LES tone decreased, and LES relaxation reflex occurrence is less frequent (all P < 0.05). In a subgroup analysis, comparing infants with PPI washout (N = 40) vs with continued (N = 9) PPI therapy, no differences were noted for aerodigestive reflex response frequency-occurrence (all P > 0.05).

DISCUSSION

In infants with GERD, feeding modification with acid suppression is not superior to acid suppression alone in modifying aerodigestive reflexes (frequency, sensation, or magnitude). Contiguous areas targeted by GER, i.e., LES and distal esophageal functions, worsened at follow-up for both groups despite PPI therapy. Maturation is likely the key factor for GERD resolution in infants, justifying the use of placebo in clinical trials for objectively determined GERD.

Secretion Management in Tracheostomized Infants using Unconventional Approaches and Outcomes: A Case Series

OBJECTIVE

This study aimed to increase the understanding of secretion management in infants with tracheostomies. In this case series, we describe objective evidence for an unconventional approach in infants refractory to conventional management techniques.

STUDY DESIGN

Case study of two NICU infants utilizing high-resolution manometry was undertaken using personalized oral stimulation protocols with fruity foods.

RESULTS

Oral stimulation improved infant swallowing to clear secretions and reduce the need for suctioning.

CONCLUSION

Innovative oral stimulation protocols are needed to improve swallowing in high-risk infants.

Mechanisms of bradycardia in premature infants: Aerodigestive-cardiac regulatory-rhythm interactions

OBJECTIVE

Eating difficulties coupled with cardiorespiratory spells delay acquisition of feeding milestones in convalescing neonates, and the mechanisms are unclear. Aims were to examine and compare the pharyngoesophageal-cardiorespiratory (PECR) response characteristics: (a) in control neonates and those with recurrent bradycardia spells; and (b) during pharyngeal stimulation when bradycardia occurs versus when no bradycardia occurs.

METHODS

Preterm infants (N = 40, 27 ± 3 weeks gestation), underwent concurrent pharyngoesophageal manometry, electrocardiography, respiratory inductance plethysmography, and nasal airflow thermistor to evaluate pharyngoesophageal motility, heart rate (HR), and respiration during graded abrupt pharyngeal sterile water stimuli. Infants with recurrent bradycardia (N = 28) and controls (N = 12) were evaluated at 38 (38-40) and 39 (38-40) weeks postmenstrual age, respectively. Comparisons were performed (a) between study and control groups; and (b) among HR responses of <80 BPM, 80-100 BPM, and >100 BPM.

RESULTS

Overall, characteristics of PECR responses in infants with a history of recurrent bradycardia (vs. controls) did not differ (p > .05). However, when pharyngeal stimulus induced severe bradycardia (<80 BPM): prolonged respiratory rhythm change, increased pharyngeal activity, increased esophageal dysmotility (as evidenced by prolonged esophageal inhibition and motor activity), and prolonged lower esophageal sphincter relaxation were noted (all p < .05).

CONCLUSIONS

In control infants and those with recurrent bradycardia, pharyngeal stimulation results in similar PECR response characteristics. However, when severe bradycardia occurs, PECR response characteristics are distinct. The mechanisms of severe bradycardia spells are related to abnormal prolongation of vagal inhibitory effects on cardiorespiratory rhythms in conjunction with prolonged esophageal inhibition and delays with terminal swallow.

Approach to Feeding Difficulties in Neonates and Infants: A Comprehensive Overview

Deglutition disorders (DD) can be transient and considered as physiologic during normal maturation. However, when oral feeding milestones are impaired and bothersome symptoms and aerodigestive consequences are associated, it is interpreted as DD with varying specific entities, such as feeding difficulties, swallowing disorders, aerodigestive illness, and aspiration syndromes. Symptoms related to DD are heterogeneous and managed empirically. This article clarifies current controversies, explains the potential role of safe feeding and physiologic and pathophysiologic perspectives, and highlights current advances in the field. Evidence basis for diagnostic strategies is discussed, and involves evaluation for structure and function tests, and nutrition and feeding assessment.

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.

Pilot Study of Pharyngoesophageal Dysmotility Mechanisms in Dysphagic Infants of Diabetic Mothers

OBJECTIVE

Swallowing difficulties are common in infants of diabetic mothers (IDM) and mechanisms are unclear. We tested the hypothesis that pharyngoesophageal motility reflexes are distinct in IDMs compared with healthy controls in a pilot study.

STUDY DESIGN

Basal and adaptive pharyngoesophageal motility characteristics of 20 dysphagic IDMs and 10 controls were studied using purpose-built micromanometry system.

RESULTS

During basal swallows, IDMs had lower frequency of deglutition apneas (62.5 vs. 95.4%) and longer active upper esophageal sphincter (UES) relaxation duration (0.8 ± 0.1 vs. 0.4 ± 0.1 second), whereas during adaptive swallows, IDMs had longer response latency to esophageal peristalsis onset (24.4 ± 2.1 vs. 9.7 ± 2.9 seconds) and longer lower esophageal sphincter nadir duration (28.9 ± 3.2 vs. 12.9 ± 4.6) (all p < 0.05) compared with controls. Nine in the IDM group needed gastrostomy feeding tube at hospital discharge versus none in controls.

CONCLUSION

Feeding difficulties in IDMs are likely to be associated with maladapted or maldeveloped vagal neuropathy mechanisms manifesting as dysregulation of pharyngeal-airway interactions, longer active UES relaxation response, delays in the activation of esophageal contractile apparatus during peristalsis, and prolonged inhibition at the gastroesophageal junction.

Pharyngeal contractile and regulatory characteristics are distinct during nutritive oral stimulus in preterm-born infants: Implications for clinical and research applications

BACKGROUND

Maturation of pharyngeal swallowing during neonatal oral feeding is unknown. Our objective was to evaluate pharyngeal functioning using high-resolution manometry (HRM) during nutritive oral stimulus and test the hypothesis that pharyngeal contractility and regulation are distinct in preterm-born infants.

METHODS

High-resolution manometry data during oral milk feeding were analyzed for pharyngeal contractile (PhCI, mm Hg cm s) and regulatory (number and frequency of pharyngeal contractions and bursts, pharyngeal activity-to-quiescence ratio, upper esophageal sphincter nadir pressure) characteristics in 23 preterm (<38 weeks' gestation) and 18 full-term-born infants at term maturation. Mixed linear models and stepwise regression methods were used.

RESULTS

Despite more oral feeding experiences (P < 0.05), preterm infants (vs full-term), consumed less milk volume (P < 0.001), had lesser pharyngeal contractions within bursts (P = 0.04), lower pharyngeal contraction frequency (P < 0.01), and lower pharyngeal activity (P = 0.03), but higher PhCI per individual contraction (P = 0.01). PhCI is higher for longer PMA (P < 0.05), higher UES nadir pressures (P < 0.05), and lower pharyngeal contraction frequency (P < 0.05).

CONCLUSIONS

Nutritive oral milk stimulus provoked pharyngeal contractility characteristics is distinct in preterm-born. Despite more oral nutritive experiences, preterm infants had underdeveloped excitatory and inhibitory rhythmic activity. Cranial nerve IX and X effects on sensory-motor responses and feedback (excitation-inhibitory rhythm regulation) remain immature among preterm-born even at full-term maturational status. We speculate the relationship between PhCI and UES regulatory activity contributes to the observed differences in preterm and full-term infants.

Gastroesophageal Reflux Disease in the Neonatal Intensive Care Unit Infant: Who Needs to Be Treated and What Approach Is Beneficial?

Gastroesophageal reflux (GER) and GER disease (GERD) pertaining to infants in the neonatal intensive care unit (NICU) are reviewed, based on research in this specific population. The developmental biology of the gastroesophageal junction, physiology of GER, and pathophysiology of GERD in this setting are summarized, and risk factors for GER and GERD identified. The epidemiology, economic burden, and controversies surrounding GERD in NICU infants are addressed, and an approach to GER and GERD in these patients formulated. Recent advancements in individual assessment of GER and GERD in the NICU infant are examined, and evidence-based guidelines for their adoption provided.

Mechanisms of Aerodigestive Symptoms in Infants with Varying Acid Reflux Index Determined by Esophageal Manometry

OBJECTIVE

To test whether symptom generation in infants is related to the severity of gastroesophageal reflux disease (GERD) symptoms as determined by the Acid Reflux Index (ARI), stimulus media, and stimulus volume during provocative esophageal manometry.

STUDY DESIGN

Symptomatic neonates (n = 74) born at a median of 28.9 weeks gestation (range, 23.4-39.4 weeks) were studied at a median of 41.0 weeks (range, 34.6-48.0 weeks) postmenstrual age using 24-hour pH-impedance methods to determine ARI severity, followed by provocative esophageal manometry with graded mid-esophageal infusions (0.1-5.0 mL) of air, water, and apple juice. Peristaltic reflexes and symptom characteristics were compared among ARI severity categories using linear mixed models and generalized estimating equations.

RESULTS

The effects of 2635 separate esophageal stimuli on reflexes and symptoms were analyzed. Peristaltic reflexes occurred in 1880 infusions (71%), and physical, cardiorespiratory, sensory symptoms were seen in 439 infusions (17%). Symptom prevalence did not differ across the ARI severity categories (ARI <3, 18%; ARI 3-7, 17%; ARI >7, 16%; P = 1.0). Symptom and peristaltic responses increased with incremental stimulus volumes (all media, P < .001).

CONCLUSIONS

Symptoms and peristaltic reflexes are manifestations of the recruitment of several neurosensory and neuromotor pathways evoked by mid-esophageal infusions. ARI severity grade plays no role in symptom generation, indicating that GERD should not be diagnosed and severity should not be assigned based on symptoms alone. An increase in symptom occurrence was noted with increasing stimulus volumes, which provided increased activation of receptors, afferents, and efferents in evoking peristaltic clearance reflexes.

Differentiation of esophageal pH-impedance characteristics classified by the mucosal integrity marker in human neonates

BACKGROUND

In adults, distal baseline impedance (BI) is a determinant of esophageal mucosal integrity with values <900 Ω indicating inflammation. Relationships between acid gastroesophageal reflux (GER) and BI in neonates are unclear.

METHODS

NICU infants (N = 198, 30.4 ± 0.3 weeks gestation) were evaluated at 43 ± 0.4 weeks postmenstrual age using 24-h pH-impedance. Ten randomly selected 1-min windows during rest from the distal impedance channel (Z6) were averaged. Chi-square, t-tests, and ANOVA were used to compare pH-impedance and symptom characteristics by BI severity (BI < 900 Ω, BI 900-2000 Ω, BI > 2000 Ω). Regression analysis was used to identify potential contributing factors of BI.

RESULTS

In BI < 900 Ω: (1) pH-impedance characteristics were increased (acid reflux event frequency, duration, and severity, all P < 0.05 vs. BI > 2000 Ω), and (2) positive symptom correlations were noted with bolus (73%) and acid events (55%). Significant predictors of BI included chronological age, acid reflux index, and BPD diagnosis (all P < 0.05).

CONCLUSIONS

Low BI is associated with prolonged acid exposure, delayed clearance, and greater aerodigestive symptom prevalence, likely associated with inflammation and or increased mucosal permeability. BI > 2000 Ω likely involves little or no inflammation because acid exposure is minimal. Combination of SAP, pH-impedance metrics, and BI along with the clarification of dysmotility mechanisms provides the rationale for personalized anti-reflux therapies as needed.

Pharyngoesophageal and cardiorespiratory interactions: potential implications for premature infants at risk of clinically significant cardiorespiratory events

The aims of this study were to 1) examine pharyngoesophageal and cardiorespiratory responses to provoking pharyngeal stimuli, and 2) to determine potential contributory factors impacting heart rate (HR) changes to provide insight into cardiorespiratory events occurring in preterm infants. Forty-eight neonates (19 females and 29 males, born at 27.7 ± 0.5 wk; mean ± SE) pending discharge on full oral feeds were studied at 38.7 ± 0.2 wk postmenstrual age using concurrent pharyngoesophageal manometry, electrocardiography, respiratory inductance plethysmography, and nasal airflow thermistor. Pharyngoesophageal and cardiorespiratory responses (prevalence, latency, and duration) were quantified upon abrupt pharyngeal water stimuli (0.1, 0.3, and 0.5 ml in triplicate). Mixed linear models and generalized estimating equations were used for comparisons between HR changes. Contributory factors included stimulus characteristics and subject characteristics. Of 338 pharyngeal stimuli administered, HR increased in 23 (7%), decreased in 108 (32%), and remained stable in 207 (61%) neonates. HR decrease resulted in repetitive swallowing, increased respiratory-rhythm disturbance, and decreased esophageal propagation rates (all, P < 0.05). HR responses were related to stimulus volume, stimulus flow rate, and extreme prematurity (all, P < 0.05). In preterm infants, HR remains stable in a majority of pharyngeal provocations. HR decrease, due to pharyngeal stimulation, is related to aberrant pharyngoesophageal motility and respiratory dysregulation and is magnified by prematurity. We infer that the observed aberrant responses across digestive, respiratory, and cardiovascular systems are related to maladaptive maturation of the parasympathetic nervous system. These aberrant responses may provide diagnostic clues for risk stratification of infants with troublesome cardiorespiratory events and swallowing difficulty. NEW & NOTEWORTHY Cardiorespiratory rhythms concurrent with pharyngeal, upper esophageal sphincter, and esophageal body responses were examined upon pharyngeal provocation in preterm-born infants who were studied at full-term maturation. Decreased heart rate (HR) was associated with extreme preterm birth and stimulus flow/volume. With HR decrease responses, aerodigestive reflex abnormalities were present, characterized by prolonged respiratory rhythm disturbance, repetitive multiple swallowing, and poor esophageal propagation. Promoting esophageal peristalsis may be a potential therapeutic target.

Persistent feeding difficulties among infants with fetal opioid exposure: mechanisms and clinical reasoning

Aims: Infants with fetal exposure to opioids have varying pattern of feeding difficulties mainly manifesting as difficulties with aerodigestive adaptation and disruptive feeding behavior. The reasons are unclear; in a pilot study, we determined basal and adaptive pharyngo-esophageal motility in a group of infants with fetal exposure to opioids and persistent feeding difficulties impeding their discharge. Methods: Six infants with fetal opioid exposure compared to 12 controls who underwent basal and adaptive pharyngo-esophageal manometry to characterize the basis for their symptoms. Spontaneous swallows (N = 180) and pharyngeal stimuli (N = 113)-induced swallowing responses were analyzed. Results: Resting upper esophageal sphincter (UES) pressure was similar in both the groups, but resting lower esophageal sphincter (LES) pressure was significantly high and it relaxed slowly and inadequately in opioid-exposed infants (p < .05). Upon pharyngeal provocation, opioid-exposed infants had higher LES nadir pressure, increased duration of esophageal body contraction at proximal-, mid-, and distal-esophagus, as well as greater area under the curve with distal esophageal waveforms, compared to controls (all p < .05). Conclusions: These pilot observations are suggestive of up-regulation of central vagal effects with heightened cholinergic excitatory responses and inadequate relaxation responses at the foregut, and may form the basis for persistent feeding difficulties in opioid-exposed infants. Abnormality with both sensory and motor aspects of vagal reflexes may be contributory.

Defining pharyngeal contractile integral during high-resolution manometry in neonates: a neuromotor marker of pharyngeal vigor

BACKGROUND

Pharyngeal contractility is critical for safe bolus propulsion. Pharyngeal contractile vigor can be measured by Pharyngeal Contractile Integral (PhCI): product of mean pharyngeal contractile amplitude, length, and duration. We characterized PhCI in neonates and examined the hypothesis that PhCI differs with mode of stimulation.

METHODS

Nineteen neonates born at 38.6 (34-41) weeks gestation were evaluated at 42.9 (40.4-44.0) weeks postmenstrual age using high-resolution manometry (HRM). PhCI was calculated using: (a) Conventional and (b) Automated Swallow Detection algorithm (ASDA) methods. Contractility metrics of all pharyngeal regions were examined using mixed statistical models during spontaneous and adaptive state (pharyngeal and oral stimulus) swallowing.

RESULTS

PhCI of oral stimuli swallows were distinct from pharyngeal stimuli and spontaneous swallows (P < 0.05). Correlation between conventional and ASDA methods was high (P < 0.001). PhCI increased with swallows for pharyngeal stimulation (P < 0.05) but remained stable for swallows with oral stimulation. PhCI differed between proximal and distal pharynx (P < 0.001).

CONCLUSIONS

PhCI is a novel reliable metric capable of distinguishing (1) proximal and distal pharyngeal activity, (2) effects of oral and pharyngeal stimulation, and (3) effects of prolonged stimulation. Changes in pharyngeal contractility with maturation, disease, and therapies can be examined with PhCI.

The Effect of Additives for Reflux or Dysphagia Management on Osmolality in Ready-to-Feed Preterm Formula: Practice Implications

BACKGROUND

A common osmolality threshold for feedings is to stay <450 mOsm/kg for normal infants. Preterm formulas are frequently modified to improve growth, modify nutrition, and manage gastroesophageal reflux (GER) or dysphagia. Relationships between osmolality and additives to ready-to-feed preterm formulas are unclear. Our aims were to evaluate and compare the effects of caloric density, thickening agent recipes, and supplements to ready-to-feed preterm formula on osmolality.

METHODS

A freezing point osmometer was used to measure the osmolality of 47 preterm infant formula combinations with varying caloric densities (ready-to-feed 22 and 30 cal/oz), thickening agents (rice vs oatmeal cereal), thickener amounts (0.0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 tsp/oz), and combinations of supplements (saline, iron, vitamin D, or multivitamin). Ten samples per combination were tested using a 10-μL pipette. Comparisons were made using analysis of variance and t-tests for group and pair-wise comparisons, respectively.

RESULTS

A total of 470 osmolality samples were analyzed: (1) raters had high agreement (r = 0.98; P < .001); (2) for every 0.5 tsp/oz of thickener, the osmolality increases by 30 mOsm/kg (P < .001); (3) osmolality was higher with the oatmeal (vs rice) thickening agent (P < .001); and (4) vitamin and electrolyte supplement combinations increase osmolality.

CONCLUSIONS

Alteration of ready-to-feed preterm formulas may significantly increase osmolality and have unintended consequences. Caution and monitoring should be exercised with modifying ready-to-feed preterm formulas for regurgitation, rumination, GER, dysphagia, feeding intolerance, or emesis. This study supports the concept of achieving volume tolerance before further manipulation of additives.

Infant Pulmonary Function Testing and Phenotypes in Severe Bronchopulmonary Dysplasia

BACKGROUND

The definition of severe bronchopulmonary dysplasia (sBPD) is based on respiratory support needs. The management of a patient with sBPD remains empirical and is highly variable among providers. Our objective in this study was to test the hypothesis that infant pulmonary function testing (iPFT) would reveal distinct phenotypes in patients with established sBPD during the initial NICU stay.

METHODS

A prospective cohort study with data prospectively collected on infants with sBPD from May 1, 2003, to June 30, 2016. iPFT data were used to classify the patients as obstructive, restrictive, or mixed.

RESULTS

The median gestational age at birth was 25 weeks (interquartile range [IQR], 24-27 weeks) and the median birth weight was 707 g (IQR, 581-925 g). At the time of iPFT, the median postmenstrual age was 52 weeks (IQR, 45-63 weeks), and the median weight was 4.4 kg (IQR, 3.7-6.0 kg). There were 56 (51%) patients with obstructive, 44 (40%) with mixed, and 10 (9%) with restrictive phenotypes. Moderate or severe obstruction was seen in 86% of the obstructive group and 78% of the mixed group. Of the restrictive patients, 70% had moderate and 30% had mild restriction. Bronchodilator response was seen in 74% of obstructive, 63% of mixed, and 25% of restrictive patients.

CONCLUSIONS

Our findings reveal that sBPD as it is currently defined includes distinct phenotypes. Future researchers of diagnostic approaches to this population should consider the development of bedside tests to define phenotypes, and researchers in future therapeutic trials should consider the use of pulmonary function phenotyping in patient recruitment.

Unique Patterns of Body Composition and Anthropometric Measurements During Maturation in Neonatal Intensive Care Unit Neonates: Opportunities for Modifying Nutritional Therapy and Influencing Clinical Outcomes

BACKGROUND

Body composition is an important predictor of long-term outcomes in neonates and may be altered by several factors. Innovative methods like air displacement plethysmography (ADP) can safely and reliably measure body composition, potentially assisting in individualization of nutrition therapy.

OBJECTIVES

1) To characterize patterns of body composition change in convalescing neonates in the neonatal intensive care unit (NICU) and examine factors leading to variation. 2) To evaluate if the time interval between 2 measurements via ADP can detect significant changes.

METHODS

NICU infants underwent anthropometry and body composition measurements by ADP at 37.5±0.7 weeks (Time 1) and 41.0±0.7 weeks (Time 2) postmenstrual age. Nutrition data were recorded. Data were analyzed using paired t-tests and linear regression models, presented as mean±SE, median (IQR), or %.

RESULTS

Twenty-two neonates (54% males, 32.2±0.9 weeks gestation) were evaluated with a median interval of 3.6 (2.9-4.0) weeks between studies. Mean weight and % body fat increased significantly. There was no significant difference between mean weight and mean % body fat compared with normal references. Abdominal girth increased and mid-arm circumference decreased (p<0.01). Preterm group had higher mean % body fat (10.1) than term infants (6.5), p = 0.03.

CONCLUSION

Longitudinal assessment of body composition can effectively assess nutrition status of fragile NICU infants. Although, an interval of 2.9-4.0 weeks between consecutive measurements detected significant changes in body composition, more frequent measurements are needed to determine nutrition factors responsible for body composition changes.

Not All Children with Cystic Fibrosis Have Abnormal Esophageal Neutralization during Chemical Clearance of Acid Reflux

PURPOSE

Acid neutralization during chemical clearance is significantly prolonged in children with cystic fibrosis, compared to symptomatic children without cystic fibrosis. The absence of available reference values impeded identification of abnormal findings within individual patients with and without cystic fibrosis. The present study aimed to test the hypothesis that significantly more children with cystic fibrosis have acid neutralization durations during chemical clearance that fall outside the physiological range.

METHODS

Published reference value for acid neutralization duration during chemical clearance (determined using combined impedance/pH monitoring) was used to assess esophageal acid neutralization efficiency during chemical clearance in 16 children with cystic fibrosis (3 to <18 years) and 16 age-matched children without cystic fibrosis.

RESULTS

Duration of acid neutralization during chemical clearance exceeded the upper end of the physiological range in 9 of 16 (56.3%) children with and in 3 of 16 (18.8%) children without cystic fibrosis (p=0.0412). The likelihood ratio for duration indicated that children with cystic fibrosis are 2.1-times more likely to have abnormal acid neutralization during chemical clearance, and children with abnormal acid neutralization during chemical clearance are 1.5-times more likely to have cystic fibrosis.

CONCLUSION

Significantly more (but not all) children with cystic fibrosis have abnormally prolonged esophageal clearance of acid. Children with cystic fibrosis are more likely to have abnormal acid neutralization during chemical clearance. Additional studies involving larger sample sizes are needed to address the importance of genotype, esophageal motility, composition and volume of saliva, and gastric acidity on acid neutralization efficiency in cystic fibrosis children.

Pharyngeal stimulus-induced reflexes are impaired in infants with perinatal asphyxia: Does maturation modify?

BACKGROUND

Development of pharyngo-esophageal protective reflexes among infants with hypoxic ischemic encephalopathy (HIE) is unclear. Our aim was to distinguish these reflexes from controls and examine the maturational changes in HIE infants.

METHODS

We evaluated 14 HIE infants (seven males) at 41.4±0.6 (HIE Time-1) and 46.5±0.6 (HIE Time-2) weeks postmenstrual age (PMA). Seven controls (three males) were evaluated at 43.5±1.3 weeks PMA. Graded pharyngeal stimulation with liquids (0.1, 0.3, 0.5 mL in triplicate) concurrent with high-resolution manometry was used to analyze sensory-motor components of pharyngeal reflexive swallowing (PRS), upper esophageal sphincter (UES), contractile reflex (PUCR), and esophageal body characteristics. Linear mixed and generalized estimating equation models were used for comparison among groups.

KEY RESULTS

Compared to controls, HIE infants (Time-1 and Time-2) exhibited decreased number of pharyngeal peaks and latency to terminal swallow. HIE Time-1 infants showed increased UES resting tone and distal latency, compared to controls and HIE Time-2. Contractile vigor was increasingly abnormal during maturation, compared to healthy controls. Threshold volumes and frequency distribution of primary responses (PRS: PUCR: None) were not significant among all groups.

CONCLUSIONS & INFERENCES

Compared to controls, HIE infants display significant hypertonicity of skeletal muscle components, impairment of pharyngeal provocation-induced reflexes and smooth muscle contractile vigor, reflecting poor propagation with maturation. These mechanisms may be responsible for inadequate clearance of secretions, ascending refluxate, and oropharyngeal bolus in HIE infants.

Comparative effect of the sites of anterior cervical pressure on the geometry of the upper esophageal sphincter high-pressure zone

OBJECTIVES/HYPOTHESIS

External cricoid pressure is increasingly used to augment the upper esophageal sphincter (UES). Our objective was to determine the effect of 1) pressures applied to cricoid, supracricoid, and subcricoid regions on the length and amplitude of the UES high-pressure zone (UESHPZ), and 2) the external cricoid pressure on lower esophageal sphincter (LES) tone.

STUDY DESIGN

Case-control study.

METHODS

We studied 11 patients with supraesophageal reflux (mean age 58 ± 12 years) and 10 healthy volunteers (mean age 47 ± 19 years). We tested 20, 30, and 40 mm Hg pressures to cricoid, 1 cm proximal and 1 cm distal to the cricoid. In an additional 15 healthy volunteers (mean age 46 ± 23 years), we studied the effect of external cricoid pressure on LES tone. UES and LES pressures were determined using high-resolution manometry.

RESULTS

There was significant increase of UESHPZ length with application of pressure at all sites. The increase of UESHPZ length was relatively symmetric, more orad, and more caudad when the pressure was applied at the cricoid, supracricoid, and subcricoid levels, respectively. The magnitude of pressure increase was greatest at the middle and orad part of the UESHPZ when the pressure was applied at the cricoid and supracricoid levels, respectively. The corresponding magnitude of increase in the caudad part of the UESHPZ was not observed with pressure at the subcricoid level. There was no change of the LES pressure with application of cricoid pressure.

CONCLUSIONS

The effect of external pressure on the UESHPZ is site dependent. Subcricoid pressure has the least effect on UESHPZ. External cricoid pressure at 20 to 40 mm Hg has no effect on the LES pressure.

LEVEL OF EVIDENCE

3b. Laryngoscope, 127:2466-2474, 2017.

Advances with Neonatal Aerodigestive Science in the Pursuit of Safe Swallowing in Infants: Invited Review

Feeding, swallowing, and airway protection are three distinct entities. Feeding involves a process of sequential, neurosensory, and neuromotor interactions of reflexes and behaviors facilitating ingestion. Swallowing involves anterograde bolus movement during oral-, pharyngeal-, and esophageal phases of peristalsis into stomach. During these events, coordination with airway protection is vital for homeostasis in clearing any material away from airway vicinity. Neurological-airway-digestive inter-relationships are critical to the continuum of successful feeding patterns during infancy, either in health or disease. Neonatal feeding difficulties encompass a heterogeneous group of neurological, pulmonary, and aerodigestive disorders that present with multiple signs posing as clinical conundrums. Significant research breakthroughs permitted understanding of vagal neural pathways and functional aerodigestive connectivity involved in regulating swallowing and aerodigestive functions either directly or indirectly by influencing the supra-nuclear regulatory centers and peripheral effector organs. These neurosensory and neuromotor pathways are influenced by pathologies during perinatal events, prematurity, inflammatory states, and coexisting medical and surgical conditions. Approaches to clarify pathophysiologic mapping of aerodigestive interactions, as well as translating these discoveries into the development of personalized and simplified feeding strategies to advance child health are discussed in this review article.

Brain Lesions among Orally Fed and Gastrostomy-Fed Dysphagic Preterm Infants: Can Routine Qualitative or Volumetric Quantitative Magnetic Resonance Imaging Predict Feeding Outcomes?

INTRODUCTION

The usefulness of qualitative or quantitative volumetric magnetic resonance imaging (MRI) in early detection of brain structural changes and prediction of adverse outcomes in neonatal illnesses warrants further investigation. Our aim was to correlate certain brain injuries and the brain volume of feeding-related cortical and subcortical regions with feeding method at discharge among preterm dysphagic infants.

MATERIALS AND METHODS

Using a retrospective observational study design, we examined MRI data among 43 (22 male; born at 31.5 ± 0.8 week gestation) infants who went home on oral feeding or gastrostomy feeding (G-tube). MRI scans were segmented, and volumes of brainstem, cerebellum, cerebrum, basal ganglia, thalamus, and vermis were quantified, and correlations were made with discharge feeding outcomes. Chi-squared tests were used to evaluate MRI findings vs. feeding outcomes. ANCOVA was performed on the regression model to measure the association of maturity and brain volume between groups.

RESULTS

Out of 43 infants, 44% were oral-fed and 56% were G-tube fed at hospital discharge (but not at time of the study). There was no relationship between qualitative brain lesions and feeding outcomes. Volumetric analysis revealed that cerebellum was greater (p < 0.05) in G-tube fed infants, whereas cerebrum volume was greater (p < 0.05) in oral-fed infants. Other brain regions did not show volumetric differences between groups.

CONCLUSION

This study concludes that neither qualitative nor quantitative volumetric MRI findings correlate with feeding outcomes. Understanding the complexity of swallowing and feeding difficulties in infants warrants a comprehensive and in-depth functional neurological assessment.

Somatic stimulation causes frontoparietal cortical changes in neonates: a functional near-infrared spectroscopy study

Palmar and plantar grasp are the foremost primitive neonatal reflexes and functions. Persistence of these reflexes in infancy is a sign of evolving cerebral palsy. Our aims were to establish measurement feasibility in a clinical setting and to characterize changes in oxyhemoglobin (HbO) and deoxyhemoglobin (HbD) concentration in the bilateral frontoparietal cortex in unsedated neonates at the crib-side using functional near-infrared spectroscopy (fNIRS). We hypothesized that bilateral concentration changes will occur upon somatic central and peripheral somatic stimulation. Thirteen preterm neonates (five males) underwent time 1, and six (two males) returned for time 2 (mean [Formula: see text] and 47.0 weeks, respectively). Signals from a total of 162 somatic stimuli responses were measured. Response amplitude, duration, and latency were log-transformed and compared between palmar, plantar, and oromotor stimuli using linear mixed models, adjusted for cap, electroencephalogram abnormality, time (1 versus 2), and Sarnat score, if necessary. The oromotor stimulus resulted in a 50% greater response than the palmar or plantar stimuli for HbO left and right hemisphere duration ([Formula: see text]). There were no other statistically significant differences between stimuli for any other outcome ([Formula: see text]). Utilizing fNIRS in conjunction with occupational and physical therapy maneuvers is efficacious to study modifiable and restorative neurophysiological mechanisms.

Effect of Severity of Esophageal Acidification on Sleep vs Wake Periods in Infants Presenting with Brief Resolved Unexplained Events

OBJECTIVES

To describe the pattern of gastroesophageal reflux (GER) events in wake and sleep states with increasing acid reflux index (ARI) in neonates and to test the hypothesis that GER-related symptoms are frequent in ARI >7% in wake state.

STUDY DESIGN

Infants underwent 24-hour pH-impedance studies with 6-hour concurrent video-polysomnography studies. Data were stratified based on the 24-hour ARI (% duration that esophageal pH is <4) into ARI < 3% (normal), ARI 3 ≥ to ≤7% (intermediate), and ARI >7% (abnormal). GER frequency, clearance mechanisms, and symptoms were distinguished during wake state and sleep state.

RESULTS

Total wake and sleep duration was similar (P ≥ .2) in all ARI groups. Acidic events were frequent with increasing ARI in wake state vs sleep state (P ≤ .03). The symptom index increased with increasing ARI (P ≤ .02) in both wake state and sleep state. Acid clearance time increased with increasing ARI in wake state (P ≤ .02). In ARI > 7% vs ARI ≤ 7%, frequency of acidic GER events was higher (P ≤ .02) in wake state and sleep state; proximal migration of acid (P = .03) and acid clearance time were higher in wake state (P = .0005) only. Symptom index was higher in ARI >7% vs ARI ≤ 7% in wake state (P < .0001), comparable in normal vs intermediate (P = .4), and higher in abnormal vs intermediate (P = .0004) groups.

CONCLUSIONS

Severe esophageal acid exposure (ARI >7%) is associated with increased reflux-associated symptoms in wake state. Sleep state appears to be protective regardless of ARI, likely because of greater chemosensory thresholds. Attention to posture and movements during wake state can be helpful. Scrutiny for non-GER etiologies should occur for infants presenting with life-threatening symptoms.

Characterization and mechanisms of the pharyngeal swallow activated by stimulation of the esophagus

Stimulation of the esophagus activates the pharyngeal swallow response (EPSR) in human infants and animals. The aims of this study were to characterize the stimulus and response of the EPSR and to determine the function and mechanisms generating the EPSR. Studies were conducted in 46 decerebrate cats in which pharyngeal, laryngeal, and esophageal motility was monitored using EMG, strain gauges, or manometry. The esophagus was stimulated by balloon distension or luminal fluid infusion. We found that esophageal distension increased the chance of occurrence of the EPSR, but the delay was variable. The chance of occurrence of the EPSR was related to the position, magnitude, and length of the stimulus in the esophagus. The most effective stimulus was long, strong, and situated in the cervical esophagus. Acidification of the esophagus activated pharyngeal swallows and sensitized the receptors that activate the EPSR. The EPSR was blocked by local anesthesia applied to the esophageal lumen, and electrical stimulation of the recurrent laryngeal nerve caudal to the cricoid cartilage (RLNc) activated the pharyngeal swallow response. We conclude that the EPSR is activated in a probabilistic manner. The receptors mediating the EPSR are probably mucosal slowly adapting tension receptors. The sensory neural pathway includes the RLNc and superior laryngeal nerve. We hypothesize that, because the EPSR is observed in human infants and animals, but not human adults, activation of EPSR is related to the elevated position of the larynx. In this situation, the EPSR occurs rather than secondary peristalsis to prevent supraesophageal reflux when the esophageal bolus is in the proximal esophagus.

Death by neurologic criteria in a neonate: Implications for organ donation

We illustrate a unique case of neonatal organ donation in a full-term newborn with severe hypoxic ischemic encephalopathy (HIE) and multi-organ dysfunction that underwent therapeutic hypothermia. Prolonged hypothermia permitted adequate time for recovery of certain end-organs before such time that death by neurologic criteria was declared. Parental values aligned with the opportunity for organ donation.

The physiologic coupling of sucking and swallowing coordination provides a unique process for neonatal survival

AIM

Although the coordination of sucking and swallowing is critical for successful oral intake in neonates, the mechanisms that facilitate this coordination are not well understood. This investigation sought to clarify the mechanisms that facilitate this coordination, by comparing sucks that were coordinated with swallows and sucks that were completed in isolation.

METHODS

Ten neonates with a median gestational age of 28.2 weeks, ranging from 27.0 to 35.0 weeks, were recruited from the neonatal nurseries at Nationwide Children's Hospital, Columbus, Ohio, USA. They were evaluated while bottle-feeding at term gestation for differences in characteristics between sucks that were coupled and not coupled with swallows. Suction was evaluated using an intra-oral pressure transducer, and swallows were identified using a micromanometry pharyngeal catheter. Linear mixed models were applied to distinguish sucking characteristics.

RESULTS

Suction exhibited an antiphase relationship with the generation and release of positive pharyngeal pressure during the swallow. Coupled sucks had lower suction generation and release rates (p < 0.0001), lower suction amplitude (p = 0.004), longer suction duration (p < 0.0001) and higher milk ejection pressure (p < 0.0001).

CONCLUSION

The coordination of unique sucking and swallowing movement patterns may be achieved by the infant adapting sucking kinematics around the lingual patterns that facilitate the pharyngeal swallow.

Effect of nasal noninvasive respiratory support methods on pharyngeal provocation-induced aerodigestive reflexes in infants

The pharynx is a locus of provocation among infants with aerodigestive morbidities manifesting as dysphagia, life-threatening events, aspiration-pneumonia, atelectasis, and reflux, and such infants often receive nasal respiratory support. We determined the impact of different oxygen delivery methods on pharyngeal stimulation-induced aerodigestive reflexes [room air (RA), nasal cannula (NC), and nasal continuous positive airway pressure (nCPAP)] while hypothesizing that the sensory motor characteristics of putative reflexes are distinct. Thirty eight infants (28.0 ± 0.7 wk gestation) underwent pharyngoesophageal manometry and respiratory inductance plethysmography to determine the effects of graded pharyngeal stimuli (n = 271) on upper and lower esophageal sphincters (UES, LES), swallowing, and deglutition-apnea. Comparisons were made between NC (n = 19), nCPAP (n = 9), and RA (n = 10) groups. Importantly, NC or nCPAP (vs. RA) had: 1) delayed feeding milestones (P < 0.05), 2) increased pharyngeal waveform recruitment and duration, greater UES nadir pressure, decreased esophageal contraction duration, decreased distal esophageal contraction amplitude, and decreased completely propagated esophageal peristalsis (all P < 0.05), and 3) similarly developed UES contractile and LES relaxation reflexes (P > 0.05). We conclude that aerodigestive reflexes were similarly developed in infants using noninvasive respiratory support with adequate upper and lower aerodigestive protection. Increased concern for GERD is unfounded in this population. These infants may benefit from targeted oromotor feeding therapies and safe pharyngeal bolus transit to accelerate feeding milestones.

Effects of pacifier and taste on swallowing, esophageal motility, transit, and respiratory rhythm in human neonates

BACKGROUND

Pacifier use is widely prevalent globally despite hygienic concerns and uncertain mechanistic effects on swallowing or airway safety.

AIMS

The effects of pacifier and taste interventions on pharyngo-esophageal motility, bolus transit, and respiratory rhythms were investigated by determining the upper esophageal sphincter (UES), esophageal body, esophagogastric junction (EGJ) motor patterns and deglutition apnea, respiratory rhythm disturbances, and esophageal bolus clearance.

METHODS

Fifteen infants (six males; median gestation 31 weeks and birth weight 1.4 kg) underwent high-resolution impedance manometry at 43 (41-44) weeks postmenstrual age. Manometric, respiratory, and impedance characteristics of spontaneous swallows, pacifier-associated dry swallowing and taste (pacifier dipped in 3% sucrose)-associated swallowing were analyzed. Linear mixed and generalized estimating equation models were used. Data are presented as mean ± SEM, %, or median (IQR).

KEY RESULTS

Pharyngo-esophageal motility, respiratory, and impedance characteristics of 209 swallows were analyzed (85 spontaneous swallows, 63 pacifier- swallows, 61 taste- swallows). Basal UES and EGJ pressures decreased upon pacifier (p < 0.05) and taste interventions (p < 0.05); however, esophageal motility, respiratory rhythm, and impedance transit characteristics were similar with both interventions.

CONCLUSIONS & INFERENCES

Oral stimulus with pacifier or taste interventions decreases UES and EGJ basal pressure, but has no effects on pharyngo-esophageal motility, airway interactions, or esophageal bolus transit. A decrease in central parasympathetic-cholinergic excitatory drive is likely responsible for the basal effects.

Hand-grasping and finger tapping induced similar functional near-infrared spectroscopy cortical responses

Despite promising advantages such as low cost and portability of functional near-infrared spectroscopy (fNIRS), it has yet to be widely implemented outside of basic research. Specifically, fNIRS has yet to be proven as a standalone tool within a clinical setting. The objective of this study was to assess hemodynamic concentration changes at the primary and premotor motor cortices as a result of simple whole-hand grasping and sequential finger-opposition (tapping) tasks. These tasks were repeated over 3 days in a randomized manner. Ten healthy young adults ([Formula: see text]) participated in the study. Quantitatively, no statistically significant differences were discovered between the levels of activation for the two motor tasks ([Formula: see text]). Overall, the signals were consistent across all 3 days. The findings show that both finger-opposition and hand grasping can be used interchangeably in fNIRS for assessment of motor function which would be useful in further advancing techniques for clinical implementation.

Systematic Review of Inhaled Bronchodilator and Corticosteroid Therapies in Infants with Bronchopulmonary Dysplasia: Implications and Future Directions

Background

There is much debate surrounding the use of inhaled bronchodilators and corticosteroids for infants with bronchopulmonary dysplasia (BPD).

Objective

The objective of this systematic review was to identify strengths and knowledge gaps in the literature regarding inhaled therapies in BPD and guide future research to improve long-termoutcomes.

Methods

The databases of Academic Search Complete, CINAHL, PUBMED/MEDLINE, and Scopus were searched for studies that evaluated both acute and long-term clinical outcomes related to the delivery and therapeutic efficacy of inhaled beta-agonists, anticholinergics and corticosteroids in infants with developing and/or established BPD.

Results

Of 181 articles, 22 met inclusion criteria for review. Five evaluated beta-agonist therapies (n = 84, weighted gestational age (GA) of 27.1(26–30) weeks, weighted birth weight (BW) of 974(843–1310) grams, weighted post menstrual age (PMA) of 34.8(28–39) weeks, and weighted age of 53(15–86) days old at the time of evaluation). Fourteen evaluated inhaled corticosteroids (n = 2383, GA 26.2(26–29) weeks, weighted BW of 853(760–1114) grams, weighted PMA of 27.0(26–31) weeks, and weighted age of 6(0–45) days old at time of evaluation). Three evaluated combination therapies (n = 198, weighted GA of 27.8(27–29) weeks, weighted BW of 1057(898–1247) grams, weighted PMA of 30.7(29–45) weeks, and age 20(10–111) days old at time of evaluation).

Conclusion

Whether inhaled bronchodilators and inhaled corticosteroids improve long-term outcomes in BPD remains unclear. Literature regarding these therapies mostly addresses evolving BPD. There appears to be heterogeneity in treatment responses, and may be related to varying modes of administration. Further research is needed to evaluate inhaled therapies in infants with severe BPD. Such investigations should focus on appropriate definitions of disease and subject selection, timing of therapies, and new drugs, devices and delivery methods as compared to traditional methods across all modalities of respiratory support, in addition to the assessment of long-term outcomes of initial responders.