Esophageal and upper esophageal sphincter motor function in babies

Degree of Cyclooxygenase-2 Inhibition Modulates Blood Pressure Response to Celecoxib and Naproxen

Background

Non-steroidal anti-inflammatory drugs (NSAIDs) increase the risk of adverse cardiovascular events via suppression of cyclooxygenase (COX)-2-derived prostacyclin (PGI2) formation in heart, vasculature, and kidney. The Prospective Randomized Evaluation of Celecoxib Integrated Safety versus Ibuprofen Or Naproxen (PRECISION) trial and other large clinical studies compared the cardiovascular risk of traditional NSAIDs (i.e. naproxen), which inhibit both COX isozymes, with NSAIDs selective for COX-2 (i.e. celecoxib). However, whether pharmacologically equipotent doses were used - that is, whether a similar degree of COX-2 inhibition was achieved - was not considered. We compared drug target inhibition and blood pressure response to celecoxib at the dose used by most patients in PRECISION with the lowest recommended naproxen dose for osteoarthritis, which is lower than the dose used in PRECISION.

Methods

Sixteen healthy participants (19-61 years) were treated with celecoxib (100 mg every 12h), naproxen (250 mg every 12h), or placebo administered twice daily for seven days in a double-blind, crossover design randomized by order. On Day 7 when drug levels had reached steady state, the degree of COX inhibition was assessed ex vivo and in vivo. Ambulatory blood pressure was measured throughout the final 12h dosing interval.

Results

Both NSAIDs inhibited COX-2 activity relative to placebo, but naproxen inhibited COX-2 activity to a greater degree (62.9±21.7%) than celecoxib (35.7±25.2%; p<0.05). Similarly, naproxen treatment inhibited PGI2 formation in vivo (48.0±24.9%) to a greater degree than celecoxib (26.7±24.6%; p<0.05). Naproxen significantly increased blood pressure compared to celecoxib (differences in least-square means of mean arterial pressure: 2.5 mm Hg (95% CI: 1.5, 3.5); systolic blood pressure: 4.0 mm Hg (95% CI: 2.9, 5.1); diastolic blood pressure: 1.8 mm Hg (95% CI: 0.8, 2.8); p<0.05 for all). The difference in systolic blood pressure relative to placebo was associated with the degree of COX-2 inhibition (p<0.05).

Conclusions

Celecoxib 200 mg/day inhibited COX-2 activity to a lesser degree than naproxen 500 mg/day, resulting in a less pronounced blood pressure increase. While the PRECISION trial concluded the non-inferiority of celecoxib regarding cardiovascular risk, this is based on a comparison of doses that are not equipotent.ClinicalTrials.gov identifier: NCT02502006 (https://clinicaltrials.gov/study/NCT02502006).

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.

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.

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.

Characterization of Esophageal and Sphincter Reflexes across Maturation in Dysphagic Infants with Oral Feeding Success vs Infants requiring Gastrostomy

To test the hypothesis that esophageal and sphincteric sensory-motor reflexes are distinct across maturation in infants with dysphagia receiving gastrostomy-tube (G-tube). This is a retrospective review of 29 dysphagic infants (N = 15 study requiring gastrostomy, N = 14 age matched control achieving oral feeds) that underwent longitudinal pharyngeal-esophageal manometry at 42.3 (37-50.2) weeks postmenstrual age (PMA) and 48.9 (43.3-57.9) weeks PMA. Graded stimuli (0.1-5 mL) of varying media (air, water, and apple juice) tested esophageal peristaltic reflex, upper esophageal sphincter contractile reflex (UESCR), and lower esophageal sphincter relaxation reflex (LESRR). Comparisons were performed between study and controls and across maturation (time-1 vs time-2). Data represented as mean ± SE or OR (95% CI). Across maturation (time-1 vs time-2): Study infants did not exhibit significant differences across in peristaltic, UES, or LES reflexes (all p > 0.05). In contrast, controls exhibited increased UES resting pressure (13 ± 3 vs 17 ± 3 mmHg, p = 0.001), LES resting pressure (22 ± 3 vs 25 ± 3 mmHg, p < 0.009), LES nadir pressure (0.5 ± 1 vs 4.3 ± 1 mmHg, p = 0.001), and esophago-deglutition responses [2.5 (1.23-4.88), p = 0.04], and decreased secondary peristalsis [0.44 (0.31-0.61), p = 0.001], UESCR [0.4 (0.25-0.65), p = 0.001], LESRR [0.4 (0.24-0.75), p = 0.01], and symptoms [0.6 (0.45-0.83), p = 0.005]. Among infants with dysphagia, esophageal provocation induced peristaltic reflex, UESCR, and LESRR advance with longitudinal maturation when infants are oral-fed successfully, but not in those who received gastrostomy. Underlying mechanisms may be related to esophageal sensitivity, afferent or efferent transmission, and coordination of upstream excitation and downstream inhibition, which can be potential therapeutic targets for improving feeding capabilities after gastrostomy placement in infants with dysphagia.

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.

The effect of non-nutritive sucking combined with oral motor stimulation and oral support on feeding performance in premature infants: A single-blind randomized-clinical trial

PURPOSE

Feeding problems are common in premature infants (PIs) and may lead to negative consequences such as malnutrition, dehydration, excessive weight loss, as well as developmental and psychological deficits. Moreover, they are associated with increased length of hospital stay/cost. There is not enough evidence on how feeding problems should be treated in PIs. The goal of this study was to investigate the effects of non-nutritive sucking combined with oral motor stimulation and oral support on feeding performance in PIs.

METHODS

A single-blind randomized clinical trial was performed on 44 PIs with feeding problems. Patients were randomly categorized into two groups: (1) combined intervention (CI) and (2) non-nutritive sucking (NNS). The CI group received NNS, oral motor stimulation and oral support simultaneously. Infants in both groups received 14 treatment sessions for 14 consecutive days. The Preterm Oral Feeding Readiness Assessment Scale (POFRAS) was used as the primary outcome measure. Weight, volume of milk intake, time to achieve full oral feeding, and length of hospital stay were secondary outcome measures. All measures were assessed before treatment, after the 7th session, after the 14th session, and after 7 days after the end of treatment.

RESULTS

Both groups improved in all outcome measures across time (P < 0.001). The improvements in the POFRAS, volume of milk intake, and time to achieve full oral feeding were significantly greater in the CI group than the NNS group (P < 0.001). The improvements attained in weight and length of hospital stay were not significantly different between the CI and NNS groups (P > 0.05). Large effect sizes were found for POFRAS score in both CI (d = 3.98) and NNS (d = 2.19) groups.

CONCLUSION

The current study showed that the combined intervention including NNS, oral motor stimulation, and oral support significantly improved the feeding performance in PIs.

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.

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.

Effects of Esophageal Acidification on Troublesome Symptoms: An Approach to Characterize True Acid GERD in Dysphagic Neonates

To quantify and compare maximal extent (height) of acid reflux events (AREs) on symptom generation in dysphagic neonates. Dysphagic neonates (N = 53), born at 30 ± 5.3 weeks gestation, underwent 24-hour pH-impedance study for the evaluation of troublesome symptoms purported to be due to gastroesophageal reflux disease (GERD). AREs (pH < 4 for >4 s) detected by impedance (Z) were categorized by maximal extent as refluxate reaching distal (Z6, Z5), middle (Z4, Z3), or proximal (Z2, Z1) impedance channels. AREs reaching the pH sensor only were categorized as distal. Symptom correlation (%, symptom index, symptom sensitivity index, and symptom associated probability) and temporal characteristics (clearance times) of AREs were analyzed using linear mixed and GEE models comparing height categories presented as mean ± SEM, median (IQR), and OR (95% CI). Of the 2003 AREs, 1) distal extent AREs (n = 1642) had increased frequency (p < 0.05), decreased ACT (p < 0.05), and decreased acidity (p < 0.05); 2) in middle and proximal AREs, acid clearance was longer than bolus clearance, (p < 0.01); and 3) the odds of having cardiorespiratory (cough or sneeze) symptoms are increased with proximal and middle AREs (p < 0.05). Most proximal ascent of AREs into middle or proximal esophagus likely activates protective aerodigestive reflexes (peristalsis) or vigilant states to facilitate bolus and chemical clearance. Heightened esophageal sensitivity, acid neutralization delays, or clearance mechanism delays may accentuate multi-systemic troublesome symptoms.

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.

Infant gastro-oesophageal reflux disease (GORD): Australian GP attitudes and practices

AIM

The aim of this study was to evaluate the attitudes and practices of Australian general practitioners (GPs) regarding infant gastro-oesophageal reflux disease (GORD) diagnosis and management.

METHODS

A national cross-sectional survey, involving a random sample of currently practising Australian GPs (n = 2319) was undertaken between July and September 2011. GPs attitudes and management of infant GORD were surveyed via an online and paper-based 41-item questionnaire.

RESULTS

In total, 400 responses were analysed (17.24% response rate). The majority of GPs employed empirical trials of acid-suppression medication and/or lifestyle modifications to diagnose infant GORD. GPs frequently recommended dietary modification despite the belief that they were only moderately effective at best. In addition, GPs frequently prescribed acid-suppression medication, despite concerns regarding their safety in the infant population. Other GP concerns included the lack of clinical guidelines and education for GPs about infant GORD, as well as the level of evidence available for the safety and efficacy of diagnostic tests and treatments.

CONCLUSION

Despite the important role Australian GPs play in the diagnosis and management of infant GORD, high-level evidence-based guidelines for GPs are lacking. Consequently, GPs engage in diagnostic and management practices despite their concerns regarding the safety and effectiveness.

Oral Motor Intervention Improved the Oral Feeding in Preterm Infants: Evidence Based on a Meta-Analysis With Trial Sequential Analysis

Oral feeding for preterm infants has been a thorny problem worldwide. To improve the efficacy of oral feeding in preterm infants, oral motor intervention (OMI), which consists of nonnutritive sucking, oral stimulation, and oral support, was developed. Published studies demonstrated that OMI may be as an alternative treatment to solve this problem; however, these results remain controversial. We conducted a meta-analysis with trial sequential analysis (TSA) to objectively evaluate the potential of OMI for improving the current status of oral feeding in preterm infants.A search of PubMed, EMBASE, Web of Science, the Cochrane Library, and China National Knowledge Infrastructure was performed to capture relevant citations until at the end of October, 2014. Lists of references of eligible studies and reviews were also hand-checked to include any latent studies. Two independent investigators screened literature, extracted data, and assessed the methodology, and then a meta-analysis and TSA was performed by using Reviewer Manager (RevMan) 5.3 and TSA 0.9 beta, respectively.A total of 11 randomized controlled trials (RCTs), which included 855 participants, were incorporated into our meta-analysis. The meta-analyses suggested that OMI is associated with the reduced transition time (ie, the time needed from tube feeding to totally oral feeding) (mean difference [MD], -4.03; 95% confidence interval [CI], -5.22 to -2.84), shorten hospital stays (MD, -3.64; 95% CI, -5.57 to -1.71), increased feeding efficiency (MD, 0.08; 95% CI, 0.36-1.27), and intake of milk (MD, 0.14; 95% CI, 0.06-0.21) rather than weight gain. Results of TSA for each outcomes of interest confirmed these pooled results.With present evidences, OMI can be as an alternative to improve the condition of transition time, length of hospital stays, feeding efficiency, and intake of milk in preterm infants. However, the pooled results may be impaired due to low quality included, and thus, well-designed and large RCTs were needed to further established effects.

The Effects of Non-Nutritive Sucking and Pre-Feeding Oral Stimulation on Time to Achieve Independent Oral Feeding for Preterm Infants

Background:

The survival rates of preterm infants has increased over the last years, but oral feeding difficulties are the most common problems encountered by them

Objectives:

This study aimed at comparing the effects of non-nutritive sucking (NNS) and pre-feeding oral stimulation on feeding skills, length of hospital stay and weight gain of 26-32 weeks gestational age preterm infants in NICU, to determine the more effective intervention.

Patients and Methods:

Thirty-two preterm infants were assigned randomly into three groups. One intervention group received pre-feeding oral stimulation program and the other received non-nutritive sucking stimulation, while the control group received a sham intervention. Gestational age of infants was calculated during 1, 4 and 8 oral feeding and discharge time from NICU. The infants’ weights were measured weekly from birth and at discharge time.

Results:

Mean gestational age on 8 time oral feeding per day, in 3 groups was not significant (P = 0.282). Although NNS and pre-feeding oral stimulation groups has fulfilled this criterion 7.55 and 6.07 days sooner than the control group, respectively (a result which is of great clinical and economic importance), but the difference did not reach statistical significance. Weight gaining at discharge time in NNS group was significantly higher than control and pre-feeding oral stimulation groups (P < 0.05).

Conclusions:

This study revealed that pre-feeding oral stimulation and NNS programs both were effective on oral feeding skills and weight gaining of the immature newborns. Yet, it seems that NNS program was more effective than pre-feeding oral stimulation on weight gaining.

Effect of nonnutritive sucking and oral stimulation on feeding performance in preterm infants: a randomized controlled trial

OBJECTIVES

To evaluate the effectiveness of nonnutritive sucking (NNS) and oral stimulation (OS), either applied alone or in combination, to reduce the transition time from tube feeding to independent oral feeding.

DESIGN

Randomized controlled trial.

SETTING

A 40-bed neonatal ICU in a university hospital in the People's Republic of China.

PATIENTS

A total of 120 preterm infants were admitted to the neonatal ICU from December 2012 to July 2013.

INTERVENTIONS

Oral motor interventions.

MEASUREMENTS AND MAIN RESULTS

One hundred twelve preterm infants were assigned to three intervention groups (NNS, OS, and combined NNS + OS) and one control group. Primary outcome was the number of days needed from introduction of oral feeding to autonomous oral feeding (transition time). Secondary outcome measures were the rate of milk transfer (mL/min), proficiency (intake first 5 min/volume ordered), volume transfer (volume transferred during entire feeding/volume prescribed), weight, and hospital length of stay. Transition time was reduced in the three intervention groups compared with the control group (p < 0.001). The milk transfer rate in the three intervention groups was greater than in the control group (F3,363 = 15.37; p < 0.001). Proficiency in the NNS and OS groups did not exceed that in the control group while the proficiency in the NNS + OS group was greater than that in the control group at the stage when the infants initiated the oral feeding (p = 0.035). Among all groups, no significant difference was found on weight gain and length of stay.

CONCLUSIONS

The combined NNS + OS intervention reduced the transition time from introduction to independent oral feeding and enhanced the milk transfer rate. The combined intervention seems to have a beneficial effect on oral feeding proficiency in preterm infants.

Esophageal mechanosensitive mechanisms are impaired in neonates with hypoxic-ischemic encephalopathy

OBJECTIVES

To test the hypothesis that esophageal mechanodistention in infants with hypoxic-ischemic encephalopathy (HIE) results in altered upper esophageal sphincter (UES), esophageal body, and lower esophageal sphincter (LES) responses, compared with controls. As a secondary aim, we tested the hypothesis that infants with HIE receiving therapeutic hypothermia had different aerodigestive reflex characteristics than infants with HIE who received traditional neonatal care.

STUDY DESIGN

Provocative esophageal manometry was performed in 34 neonates (27 with HIE and 7 controls). Mechanodistention was performed using graded volumes of air. Peristaltic reflexes, UES contractile reflexes, and LES relaxation reflexes were analyzed for frequency, magnitude, and aberrancies.

RESULTS

Infants with HIE demonstrated more rapid recruitment of responses and greater UES magnitude (P < .05). They had more frequent secondary peristalsis and lower LES nadir pressures with prolonged LES nadir durations (P < .05). Most notable were the prolonged peristaltic response durations and increases in the number of polymorphic waveforms (P < .05). Compared with infants with HIE receiving traditional care, infants with HIE treated with hypothermia had higher UES pressures and shorter peristaltic response duration (P < .05).

CONCLUSIONS

Mechanodistention in infants with HIE results in upregulation of central vagal effects (ie, heightened cholinergic excitatory responses as demonstrated by exaggerated UES contractile reflex activity and heightened inhibitory responses evident by exaggerated LES relaxation reflex activity). Prolonged and poorly coordinated peristaltic responses may underlie dysfunction of aerodigestive regulation. Modulation of sensorimotor aspects of aerodigestive reflexes is altered in infants with HIE, and hypothermia may further modify such effects.

Response of the upper esophageal sphincter to esophageal distension is affected by posture, velocity, volume, and composition of the infusate

BACKGROUND & AIMS

Studies of the pressure response of the upper esophageal sphincter (UES) to simulated or spontaneous gastroesophageal reflux have shown conflicting results. These discrepancies could result from uncontrolled influence of variables such as posture, volume, and velocity of distension. We characterized in humans the effects of these variables on UES pressure response to esophageal distension.

METHODS

We studied 12 healthy volunteers (average, 27 ± 5 years old; 6 male) using concurrent esophageal infusion and high-resolution manometry to determine UES, lower esophageal sphincter, and intraesophageal pressure values. Reflux events were simulated by distal esophageal injections of room temperature air and water (5, 10, 20, and 50 mL) in individuals in 3 positions (upright, supine, and semisupine). Frequencies of various UES responses were compared using χ(2) analysis. Multinomial logistical regression analysis was used to identify factors that determine the UES response.

RESULTS

UES contraction and relaxation were the overriding responses to esophageal water and air distension, respectively, in a volume-dependent fashion (P < .001). Water-induced UES contraction and air-induced UES relaxation were the predominant responses among individuals in supine and upright positions, respectively (P < .001). The prevalence of their respective predominant response significantly decreased in the opposite position. Proximal esophageal dp/dt significantly and independently differentiated the UES response to infusion with water or air.

CONCLUSIONS

The UES response to esophageal distension is affected by combined effects of posture (spatial orientation of the esophagus), physical properties, and volume of refluxate, as well as the magnitude and rate of increase in intraesophageal pressure. The UES response to esophageal distension can be predicted using a model that incorporates these factors.

Development of pharyngo-esophageal physiology during swallowing in the preterm infant

BACKGROUND

Poor feeding is a common cause of prolonged hospitalization of preterm infants. Pharyngeal and upper esophageal sphincter (UES) function of preterm infants has been technically difficult to assess and is therefore poorly characterized. The aim of this study was to assess the development of pharyngeal motility, UES function, and their coordination during nutritive swallowing in preterm infants.

METHODS

Development of swallowing was assessed in 18 preterm infants. High resolution manometry was performed at first oral feeding attempt (31-32 week) and then weekly for 4 weeks. Pharyngeal and UES pressure changes were characterized in 980 swallows.

KEY RESULTS

During swallowing, we observed an age-related increase in peak pharyngeal pressure at the laryngeal inlet (1 cm above UES) but an age-related decrease in the time required for the UES to fully relax to nadir. Analysis of the timing of proximal pharyngeal contractile peak and UES nadir showed that the UES was not fully relaxed when bolus propulsive forces were at their peak in the youngest infants.

CONCLUSIONS & INFERENCES

Results show developmental changes in infant swallow physiology that can be clearly linked to the effectiveness of nutritive swallowing. Most preterm infants demonstrated poor pharyngeal pressures at the laryngeal inlet coupled with poor coordination of pharyngeal propulsion with UES relaxation. These pressure patterns were less efficient than those demonstrated by older infants who were more adept at feeding. These observations may explain why infants under 34 weeks are physiologically unable to feed effectively and experience frequent choking and fatigue during feeding.

Lower esophageal sphincter relaxation reflex kinetics: effects of peristaltic reflexes and maturation in human premature neonates

We defined the sensory-motor characteristics of the lower esophageal sphincter relaxation (LESR) (stimulus threshold volume, response onset, and relaxation period, relaxation magnitude, nadir) during maturation in human neonates. We hypothesized that LESR kinetics differs during maturation and with peristaltic reflex type. Basal and adaptive esophageal motility testing was performed (N = 20 premature neonates) at 34.7 and 39.1 wk (time 1 and time 2). Effects of midesophageal provocation with graded stimuli (N = 1,267 stimuli, air and liquids) on LESR kinetics during esophagodeglutition response (EDR) and secondary peristalsis (SP) were analyzed by mixed models. Frequency of LESR with basal primary peristalsis were different during maturation (P = 0.03). During adaptive responses with maturation, 1) the frequencies of peristaltic reflexes and LESR were similar; 2) liquid stimuli resulted in a shorter LESR response latency and LESR nadir and greater LESR magnitude (all P < 0.05); 3) media differences were noted with LESR response latency (air vs. liquids, P < 0.02); and 4) infusion flow rate-LESR were different (P < 0.01 for air and liquids). Mechanistically, 1) frequency of LESR was greater during peristaltic reflexes at both times (vs. none, P < 0.0001); 2) LESR response latency, duration, and time to complete LESR were longer with EDR (all P < 0.05, vs. SP at time 2); and 3) graded stimulus volume LESR were different for air and liquids (P < 0.01). In conclusion, sensory-motor characteristics of LESR depend on the mechanosensitive properties of the stimulus (media, volume, flow), type of peristaltic reflex, and postnatal maturation. Maturation modulates an increased recruitment of inhibitory pathways that favor LESR.

Assessment of dysphagia in infants with facial malformations

In infants with facial malformation, dysphagia is frequent and can lead to respiratory and nutritional complications whatever the phenotype. The aim of our study was to assess the severity and mechanisms of dysphagia in infants with facial malformations in order to guide therapeutic management. Forty-two newborn infants with dysphagia and recognizable malformation patterns other than isolated Pierre Robin sequence had: (1) needle electromyography (EMG) of muscles of the face, tongue, and soft palate; (2) two-channel EMG during bottle feeding; and (3) esophageal manometry (EM). The results were compared by clinical dysphagia-grading groups and by age at cessation of enteral feeding. Although micrognathia (86%) and cleft or high-arched palate (76%) were common, the key clinical finding that correlated with the likelihood of respiratory complications was glossoptosis (p<0.01). EMG signs of denervation correlated with respiratory complications (p<0.05) and the duration of enteral feeding (p<0.01). EMG during bottle feeding showed disturbed motor organization at the pharyngeal level in 27 of 37 patients. The severity of pharyngeal incoordination correlated with the duration of enteral feeding (p<0.025). All 21 patients examined by EM had dysfunction at the esophageal level. Thus, in the assessment of upper digestive tract dysfunction, our clinical grading system, EMG, and EM yield convergent information that is relevant to the management of dysphagic infants with facial malformations. Much of the information is obtainable only from EMG.

Pharyngeal swallowing: defining pharyngeal and upper esophageal sphincter relationships in human neonates

OBJECTIVE

To test the hypothesis that the sensorimotor characteristics of the reflexes evoked on stimulation with air and water infusions differ by studying the effect of pharyngeal stimulation on pharyngeal-upper esophageal sphincter (UES) interactions in healthy neonates.

STUDY DESIGN

Pharyngo-UES-esophageal manometry was recorded in 10 neonates at 39 +/- 4 weeks postmenstrual age. Pharyngeal infusions (n = 155) of air (0.1 to 2.0 mL) and sterile water (0.1 to 0.5 mL) were given. Two types of reflexes were recognized: pharyngeal reflexive swallowing (PRS) and pharyngo-UES-contractile reflex (PUCR). Frequency occurrence, distribution of reflexes, threshold volume, response time, and stimulus-response relationship were evaluated.

RESULTS

The reflex response rates were 30% for air and 76% for water (P < .001). PRS was more frequent than PUCR with air and water (P < .05), even though the stimulation thresholds and response latencies were similar. Graded volumes of water but not air resulted in an increased frequency of PRS (P < .01).

CONCLUSIONS

PRS is more frequent than PUCR, and the 2 reflexes have distinctive characteristics in air and water stimuli. Both PRS and PUCR have implications for the evaluation of swallowing in infants.

Development of esophageal peristalsis in preterm and term neonates

BACKGROUND & AIMS

High-resolution manometry demonstrates a chain of 3 sequential pressure segments that represent esophageal peristalsis in children and adults. We performed high-resolution manometry in preterm and term neonates to determine the ontogenesis of esophageal motility with regard to this segmental architecture.

METHODS

Sixteen preterm (gestational age 32.9 +/- 2.6 weeks at examination) and 14 term neonates (38.9 +/- 1.6 weeks) underwent manometry with a 9-lumen perfused catheter having recording side holes spaced at 1-cm intervals. Pressure responses to swallows were evaluated for the presence of peristaltic segments on isobaric contour maps by an investigator who was blinded to gestational age.

RESULTS

The second segment was well developed in > or =50% of swallows in all preterm and term neonates. In contrast, the first segment was present in > or =50% of swallows in only 2 preterm neonates (12.5%) and 8 term neonates (57.1%; P < .05 for each compared with second segment) with identical findings for the third segment (12.5% preterm and 57.1% term neonates; P < .05 for each). Completed peristalses with intact segmental contraction sequences throughout the esophageal body were present in 26% +/- 6% of swallows in preterm neonates vs 55% +/- 9% in term neonates (P = .01).

CONCLUSIONS

The second pressure segment in the midesophagus (proximal smooth-muscle region) is well developed before term. Presence of other segments significantly improves at term, but peristalsis remains incomplete in nearly half of swallows. Control mechanisms for both striated- and smooth-muscle esophageal regions are incompletely developed in neonates, the outcome of which could participate in infant reflux disease.

Videomanometry reveals clinically relevant parameters of swallowing in children

OBJECTIVE

The aim of this pilot study is to demonstrate the technical and clinical feasibility of videomanometry to assess swallowing in infants and young children presenting with dysphagia.

METHODS

We performed videomanometry using a combined solid state catheter and a perfused manometric sleeve assembly in eight patients (2-28 months) presenting at a tertiary care institution with symptoms of dysphagia. Solid state sensors were positioned at the inferior margin of the valleculae and the laryngeal entrance and the upper esophageal sphincter sleeve assembly was positioned across the upper esophageal sphincter. Manometric and radiological data were digitally recorded simultaneously using a manofluoromixer. Liquid bolus swallows were recorded in each patient and different geometric parameters of deglutition were measured.

RESULTS

Placement and fixation of the catheter was well tolerated and no adverse effects occurred. The children easily swallowed test boluses as selected during clinical examination. Results indicate that pharyngeal contractility can be evaluated as well as relaxation of the upper esophageal sphincter during swallowing of wet boluses.

CONCLUSIONS

Videomanometry in young children is feasible with the limited discomfort of the placement of the catheter. It is a promising technique that will allow more accurate assessment of pediatric oropharyngeal dysphagia.

Effect of maturation of the magnitude of mechanosensitive and chemosensitive reflexes in the premature human esophagus

OBJECTIVES

To investigate the effect of esophageal mechanosensitive and chemosensitive stimulation on the magnitude and recruitment of peristaltic reflexes and upper esophageal sphincter (UES)-contractile reflex in premature infants.

STUDY DESIGN

Esophageal manometry and provocation testing were performed in the same 18 neonates at 33 and 36 weeks postmenstrual age (PMA). Mechanoreceptor and chemoreceptor stimulation were performed using graded volumes of air, water, and apple juice (pH 3.7), respectively. The frequency and magnitude of the resulting esophago-deglutition response (EDR) or secondary peristalsis (SP), and esophago-UES-contractile reflex (EUCR) were quantified.

RESULTS

Threshold volumes to evoke EDR, SP, or EUCR were similar. The recruitment and magnitude of SP and EUCR increased with volume increments of air and water in either study (P < .05). However, apple juice infusions resulted in increased recruitment of EDR in the 33 weeks group (P < .05), and SP in the 36 weeks group (P < .05). The magnitude of EUCR was also volume responsive (all media, P < .05), and significant differences between media were noted (P < .05). At maximal stimulation (1 mL, all media), sensory-motor characteristics of peristaltic and EUCR reflexes were different (P < .05) between media and groups.

CONCLUSIONS

Mechano- and chemosensitive stimuli evoke volume-dependent specific peristaltic and UES reflexes at 33 and 36 weeks PMA. The recruitment and magnitude of these reflexes are dependent on the physicochemical properties of the stimuli in healthy premature infants.

Imaging of the Esophagus in Children

The main role of the esophagus is to facilitate passage of food from the mouth to the stomach. A number of conditions can alter esophageal structure or function including congenital anomalies, trauma, infection, and neoplasm. This article reviews the anatomy, imaging evaluation, and common problems seen in the pediatric thoracic esophagus.

Manometric evaluation of esophageal-protective reflexes in infants and children

In adults, esophageal motor responses facilitate forward, or aboral, transit during swallowing, and protect the aerodigestive tract during retrograde movement of the bolus, which may occur with gastroesophageal reflux. It is unclear in the pediatric literature whether the activation of appropriate esophageal motor defense responses occurs during these events in infants. This investigation therefore studied the esophageal motor responses during the basal state and upon esophageal stimulation in infants. Using the water-perfusion manometry technique and a specially designed manometric catheter, 3 likely mechanisms that may protect the aerodigestive tract were recognized: secondary peristalsis, esophago-upper esophageal sphincter contractile reflex, and esophagodeglutition response.

Esophageal body and upper esophageal sphincter motor responses to esophageal provocation during maturation in preterm newborns

OBJECTIVES

We studied the maturation of esophageal body and upper esophageal sphincter (UES) motor responses that protect against reflux in newborns.

STUDY DESIGN

The responses of esophageal body and UES on midesophageal provocation were quantified using a micromanometric water perfusion system and a specially designed catheter with a UES sleeve and 5 side-hole recording sites. Eighteen healthy premature infants were studied twice, at 33.4 weeks' and 35.7 weeks' mean postmenstrual ages (PMAs).

RESULTS

Mean threshold volumes and the distribution of responses including secondary peristalsis, UES pressure increase, and primary peristalsis were similar for air and liquids. Secondary peristalsis and UES pressure increases were volume dependent for both studies, but their characteristics changed as PMA increased in that (1) completely propagated secondary peristalsis with liquids increased; (2) proximal esophageal contraction duration was shorter for air and liquids; and (3) propagating velocity for liquids was faster.

CONCLUSIONS

Esophageal and UES motor responses to abrupt midesophageal provocation are present as early as 33 weeks' PMA, and the response-characteristics improve during development. Reflexes that may facilitate esophageal clearance include (1) secondary peristalsis; (2) esophago-UES-contractile reflex; and (3) esophago-deglutition response.