Measurement of upper esophageal sphincter tone and relaxation during swallowing in premature infants

Variables influencing manometric parameters of deglutitive and non-deglutitive upper esophageal sphincter: A study of 89 asymptomatic participants

BACKGROUND

High-resolution manometry overcomes limitations imposed by axial and radial asymmetry as well as swallow and respiration-induced movement of the upper esophageal sphincter (UES), allowing for its reliable use in evaluation of dysphagic and reflux patients. The aim of this study was to determine normative values and their variability across position, sex, age, height, weight, BMI, and volume for clinically relevant deglutitive and non-deglutitive UES parameters.

METHODS

We studied 89 asymptomatic volunteers age 19-90 years, (45 female) during 3-10 repetitions of dry, 5 and 10 ml water swallows at 30-s intervals using high-resolution manometry.

KEY RESULTS

Upper esophageal sphincter high-pressure zone was longer in men than women and in supine than upright position. UES basal contractile integral and mean basal pressure were higher in supine compared to upright; higher in men than women, inversely correlated with age, correlated positively with height and with weight in the supine position only. UES relaxation duration was longer in upright than in supine position but not affected by age, sex, height, weight, or BMI. It was longer with 5 and 10 ml compared with dry swallows. UES minimum/nadir relaxation and mean relaxation pressures were lower in upright than supine position, increased with increase in age and were higher in men than women.

CONCLUSIONS AND INFERENCES

Position, sex, age, height, weight, and volume affect some deglutitive and non-deglutitve UES manometric parameters. BMI does not affect the studied manometric parameters. These effects should be taken into consideration in clinical evaluation of UES.

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.

Pharyngeal and upper esophageal sphincter motor dynamics during swallow in children

BACKGROUND

Motor abnormalities of pharyngeal contraction or upper esophageal sphincter (UES) relaxation can lead to swallowing problems.

METHODS

We reviewed high-resolution esophageal manometry of children ≤18 years and classified into two groups based on the results of videofluoroscopic study of swallow (VFSS), as normal or abnormal. The UES metrics (integrated relaxation pressure [IRP], resting pressure [URP], and nadir pressure [UNP]), as well as peak pharyngeal pressure (velopharyngeal and meso-hypopharyngeal), were analyzed.

RESULTS

UES metrics: There were 142 and 19 subjects in the normal and abnormal groups, respectively. In the normal group, the median UES-IRP at 0.2, 0.4, 0.6, 0.8 seconds, URP, and UNP were 1.0, 4.0, 11.0, 18.0, 53.5, and -1.0 mm Hg while in the abnormal group were 10.0, 13.0, 21.0, 25.5, 47.0, and 8.0 mm Hg. The UES-IRP at 0.2, 0.4, 0.6 seconds, and UNP was significantly higher in the abnormal group. Pharyngeal metrics: We included 58 subjects in normal and 10 subjects in the abnormal group. The median of peak velopharyngeal and meso-hypopharyngeal pressures were lower in the abnormal group; 188.50 vs 210.50, P = .185 and 110.00 vs 144.75 mm Hg, P = .065.

CONCLUSIONS AND INFERENCES

The UES-IRP was lower than adults, URP was higher than preterm but less than adults, and UNP was lower than neonates but similar to adults. The pharyngeal pressures were higher than those reported for neonates and adults. Our data indicate that motor dynamics of swallowing may change from neonates to adulthood and reflect a maturational process. The subjects with abnormal VFSS had significantly higher UES-IRP and UNP compared to normal VFSS.

Development of infant oral feeding skills: what do we know?

The hospital discharge of premature infants in neonatal intensive care units is often delayed due to their inability to feed by mouth safely and competently. With immature physiologic functions, infants born prematurely cannot be expected to readily feed by mouth at the equivalent age of a third trimester of gestation as the majority of their term counterparts do. Consequently, it is crucial that health care professionals gain an adequate knowledge of the development of preterm infants' oral feeding skills so as to optimize their safety and competency as they transition to oral feeding. With a greater sensitivity toward their immature skills, we can offer these infants a safer and smoother transition to independent oral feeding than is currently observed. This review article is an overview of the evidence-based research undertaken over the past 2 decades on the development of very-low-birth-weight infants' oral feeding skills. The description of the different functional levels where these infants can encounter hurdles may assist caregivers in identifying a potential cause or causes for their individual patients' oral feeding difficulties.

Development of Suck and Swallow Mechanisms in Infants

Preterm infants' hospital discharge is often delayed due to their inability to feed by mouth safely and competently. No evidence-based supported guidelines are currently available for health-care professionals caring for these infants. Available interventions advocating benefits are not readily acknowledged for lack of rigorous documentation inasmuch as any improvements may ensue from infants' normal maturation. Through research, a growing understanding of the development of nutritive sucking skills has emerged, shedding light on how and why infants may encounter oral feeding difficulties due to the immaturity of specific physiologic functions. Unfortunately, this knowledge has yet to be translated to the clinical practice to improve the diagnoses of oral feeding problems through the development of relevant assessment tools and to enhance infants' oral feeding skills through the development of efficacious preventive and therapeutic interventions. This review focuses on the maturation of the various physiologic functions implicated in the transport of a bolus from the oral cavity to the stomach. Although infants' readiness for oral feeding is deemed attained when suck, swallow, and respiration are coordinated, we do not have a clear definition of what coordination implies. We have learned that each of these functions encompasses a number of elements that mature at different times and rates. Consequently, it would appear that the proper functioning of sucking, the swallow processing, and respiration need to occur at two levels: first, the elements within each function must reach an appropriate functional maturation that can work in synchrony with each other to generate an appropriate suck, swallow process, and respiration; and second, the elements of all these distinct functions, in turn, must be able to do the same at an integrative level to ensure the safe and efficient transport of a bolus from the mouth to the stomach.

Infant apnea and gastroesophageal reflux: a critical review and framework for further investigation

Gastroesophageal reflux and apnea of prematurity are both common occurrences in premature infants. However, a causal relationship between the two remains controversial. Strong physiologic evidence indicates that a variety of protective reflex responses may elicit laryngeal adduction and apnea. Although a potential link between gastroesophageal reflux and apnea may exist through this pathway, clinical studies can be cited to either support or refute such a link in premature infants. The majority of gastroesophageal reflux episodes do not appear to be related to apnea. In a specific subset of events, a causal relationship may exist. Whether this is related to the character of the reflux episode or to a predisposition in a subpopulation of infants is unclear. This review presents the evidence for and against an association between gastroesophageal reflux and apnea, discusses techniques used in their evaluation, and identifies approaches for future investigation.

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.

Inappropriate mediastinal baroreceptor reflex as a possible cause of sudden infant death syndrome – Is thorough burping before sleep protective?

Despite extensive research, a link between the assumed mechanisms of death and known risk factors for sudden infant death syndrome (SIDS) has not yet been established. Modifiable risk factors such as prone sleeping position, nicotine exposure and thermal stress and non-avoidable risk factors like male gender and some risky socio-economic conditions could be detected, but the etiology of SIDS remains unknown. In many SIDS cases histopathological findings suggest an involvement of vital autonomic control functions and unidentified trigger factors seem to play a role. From a hypothetical point of view, a developmental sympatheticovagal imbalance of the cardiovascular reflex control could cause a predisposition for SIDS. An assumed gastroesophageal trigger impulse is possibly developed during the first weeks of life and could lead to the infant's vagal reflex death. Air swallowed during feeding escapes through the esophagus while the infant is sleeping. The temporarily bloated esophagus exerts pressure on neighboring mediastinal baroreceptors, which is potentially misinterpreted as a rise in arterial pressure. The following cardiodepressoric baroreceptor reflex could lead to arterial hypotension, bradycardia and cardiac arrest. Sleeping in prone position may create an increased thoracic pressure on mediastinal baroreceptors, causing a more pronounced vagal reflex and an increased likelihood of SIDS. Prone position in connection with soft objects in the infant's sleeping environment potentially generates an increased oculobulbar pressure, resulting in an additional cardiodepressoric condition (Aschner-Dagnini phenomenon). From the sixth month of life onwards the sympatheticovagal balance seems to have matured sufficiently to compensate the life-threatening challenges in most infants. Insufficient postprandial burping could either create another independent modifiable risk factor or present the missing link to a common trigger mechanism for SIDS. Further investigations may possibly lead to the explicit recommendation to burp all infants sufficiently and repeatedly before sleep.

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.

Characteristics of upper oesophageal sphincter and oesophageal body during maturation in healthy human neonates compared with adults

We evaluated the upper oesophageal sphincter (UOS) relationship with oesophageal body during primary peristalsis (PP) sequences in healthy human neonates during maturation and compared with that of healthy adult volunteers. Forty-nine studies were performed using a water perfusion manometry system and a specially designed oesophageal catheter with a UOS sleeve concurrent with submental electromyogram in 31 subjects in supine position (18 preterm neonates, 29.9 +/- 2.5 weeks gestation; four full-term neonates, 39.3 +/- 1.0 weeks gestation; and nine adults, 18-65 years). The preterm neonates were studied longitudinally at 33 and 36 weeks postmenstrual age (PMA) and full-term born at 40 weeks PMA. Data were compared between the groups to recognize the effects of gestation, postnatal age and ageing. We evaluated 403 consecutive spontaneous solitary swallows during maturation (preterm at time-1 vs time-2) and growth (preterm and full-term vs adults) and observed significant (P < 0.05) differences in the basal UOS resting pressure, UOS relaxation characteristics, proximal and distal oesophageal body amplitude, duration, propagation and peristaltic velocity. Characteristics of UOS and PP are well-developed by 33 weeks PMA and undergo further maturation during the postnatal period, and are significantly different from that of adult.