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

Modulation of Pharyngoesophageal Motility Characteristics During Concurrent Oral Feeding in Infants: Novel Pilot Observations

Effect of interventions or diseases on the mechanisms of swallowing difficulties, and indications to change nipples, flows, or formula thickness in high-risk infants remains unclear. We evaluated and compared the effects of nipple flows and/or formula thickness on pharyngoesophageal timing and amplitude characteristics during oral milk challenge (OMC). A total of 48 OMC trials were undertaken in 12 infants [born at 36.4 ± 3.8 weeks gestation, studied at 48.0 ± 5.6 weeks postmenstrual age (PMA)] concurrent with high resolution pharyngoesophageal manometry (HRPM). We evaluated timing and amplitude of swallowing characteristics (pharyngeal and esophageal contractile strength, duration, activity, pharyngeal peak interval variability, bursts, and rhythm) and volume intakes. We compared within and between the entities: un-thickened formula vs. thickened formula and slower- vs. faster flow nipple. OMC durations averaged 71 ± 31 s and did not differ between interventions (p > 0.05). Pharyngeal swallow rhythms (timing) and contractile characteristics were dependent on the interaction between nipple flow rates and formula thickness (p < 0.05). Thickness decreased overall contractility and modified distal pharyngeal contractile activity (p < 0.05), which is critical to opening the upper esophageal sphincter. A structural equation model was developed that revealed the influence of PMA, respiratory status, volume extracted, nipple flow rate, and thickener presence on pharyngeal swallowing frequency with a comparative fit index of 0.83. Oropharyngeal stimulus-types trigger, integrate, and modify brainstem mediated oral and pharyngeal rhythms and modulate contractility and airway protection mechanisms. Effects of therapies, maturation and diagnoses are measurable using these novel approaches at crib-side.

Characterizing Biomarkers of Continuous Peristalsis and Bolus Transit During Oral Feeding in Infants at pH-Impedance Evaluation: Clinical and Research Implications

OBJECTIVE

To examine the biomarkers of pharyngoesophageal swallowing during oral feeding sessions in infants undergoing pH-impedance testing and determine whether swallow frequencies are distinct between oral-fed and partially oral-fed infants.

STUDY DESIGN

One oral feeding session was performed in 40 infants during pH-impedance studies and measurements included swallowing frequency, multiple swallow rate, air and liquid swallow rates, esophageal swallow clearance time, and gastroesophageal reflux (GER) characteristics. Linear and mixed statistical models were applied to examine the swallowing markers and outcomes.

RESULTS

Infants (30.2 ± 4.4 weeks' birth gestation) were evaluated at 41.2 ± 0.4 weeks' postmenstrual age. Overall, 10 675 swallows were analyzed during the oral feeding sessions (19.3 ± 5.4 minutes per infant) and GER events were noted (2.5 ± 0.3 per study). Twenty-four-hour acid reflux index (ARI) was 9.5 ± 2.0%. Differences were noted in oral-fed and partially oral-fed infants for volume consumption (P < .01), consumption rate (P < .01), and length of hospital stay in days (P < .01). Infants with ARI >7% had greater frequency of swallows (P = .01). The oral-fed group had greater ARI (12.7 ± 3.3%, P = .05).

CONCLUSIONS

Oropharyngeal swallowing regulatory characteristics decrease over the feeding duration and were different between ARI >7% vs ≤7%. Although GER is less in infants who are partially oral-fed, the neonates with increased acid exposure achieved greater oral intakes and shorter hospitalizations, despite the presence of comorbidities. Pharyngoesophageal stimulation as during consistent feeding or GER events can activate peristaltic responses and rhythms, which may be contributory to the findings.

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.

Non-Nutritive Suckling System for Real-Time Characterization of Intraoral Vacuum Profile in Full Term Neonates

Infant breastfeeding diagnostics remain subjective due to the absence of instrumentation to objectively measure and understand infant oral motor skills and suckling characteristics. Qualitative diagnostic exams, such as the digital suck assessment which relies upon a clinician's gloved finger inserted into the infant's mouth, produce a diversity of diagnoses and intervention pathways due to their subjective nature. In this paper, we report on the design of a non-nutritive suckling (NNS) system which quantifies and analyzes quantitative intraoral vacuum and sucking patterns of full-term neonates in real time. In our study, we evaluate thirty neonate suckling profiles to demonstrate the technical and clinical feasibility of the system. We successfully extract the mean suck vacuum, maximum suck vacuum, frequency, burst duration, number of sucks per burst, number of sucks per minute, and number of bursts per minute. In addition, we highlight the discovery of three intraoral vacuum profile shapes that are found to be correlated to different levels of suckling characteristics. These results establish a framework for future studies to evaluate oromotor dysfunction that affect the appearance of these signals based on established normal profiles. Ultimately, with the ability to easily and quickly capture intraoral vacuum data, clinicians can more accurately perform suckling assessments to provide timely intervention and assist mothers and infants towards successful breastfeeding outcomes.

Prefeeding interventions improve oral feeding in preterm infants

OBJECTIVE

To assess whether oral stimulation (OS), nonnutritive sucking (NNS) and combined tactile/kinesthetic (T/K) interventions can improve the effects of oral feeding in preterm infants.

METHODS

A retrospective review was performed from 2014 to 2016, in which one hundred thirty preterm infants were separated into two intervention groups (the OS + NNS group and the OS + NNS + T/K group) and one control group. Infants in the two intervention groups received 30 min of interventions a day. All interventions started 48 h after stopping nasal continuous positive airway pressure until participants reached complete oral feeding.

RESULTS

The transition times of the OS + NNS, OS + NNS + T/K, and control groups from the introduction of oral feeding to independent oral feeding were 9.03 ± 0.58, 7.20 ± 0.28, and 12.17 ± 0.64 days, respectively (P < 0.05). The infants' weights at full oral feeding in the OS + NNS, OS + NNS + T/K, and control groups were 1834.58 ± 47.96, 1999.17 ± 92.62, and 1725.87 ± 40.34 g, respectively (P = 0.007). Further post hoc analyses indicated that the weight gain at full oral feeding in the OS + NNS and OS + NNS + T/K groups were more significant than the control group (P = 0.012 and P = 0.036, respectively)Conclusion: OS + NNS and OS + NNS + T/K interventions could shorten the transition time from tube feeding to independent oral feeding; OS + NNS and OS + NNS + T/K interventions improved weight gain compared to the control group. Furthermore, the OS + NNS + T/K group was superior to the OS + NNS group regarding transition time and weight gain.

Sucking versus swallowing coordination, integration, and performance in preterm and term infants

Mammalian infants must be able to integrate the acquisition, transport, and swallowing of food to effectively feed. Understanding how these processes are coordinated is critical, as they have differences in neural control and sensitivity to perturbation. Despite this, most studies of infant feeding focus on isolated processes, resulting in a limited understanding of the role of sensorimotor integration in the different processes involved in infant feeding. This is especially problematic in the context of preterm infants, as they are considered to have pathophysiological brain development and often experience feeding difficulties. Here, we use an animal model to study how the different properties of food acquisition, transport, and swallowing differ between term and preterm infants longitudinally through infancy to understand which processes are sensitive to variation in the bolus being swallowed. We found that term infants are better able to acquire milk than preterm infants, and that properties of acquisition are strongly correlated with the size of the bolus being swallowed. In contrast, behaviors occurring during the pharyngeal swallow, such as hyoid and soft palate movements, show little to no correlation with bolus size. These results highlight the pathophysiological nature of the preterm brain and also demonstrate that behaviors occurring during oral transport are much more likely to respond to sensory intervention than those occurring during the "pharyngeal phase."NEW & NOTEWORTHY Physiological maturation of infant feeding is clinically and developmentally significant, but seldom examined as an integrated function. Using longitudinal high-speed videofluoroscopic data, we found that properties of sucking, such as the length of the suck, are more sensitive to swallow physiology than those associated with the pharyngeal swallow itself, such as hyoid excursion. Prematurity impacted the function and maturation of the feeding system, resulting in a physiology that fundamentally differs from term infants by weaning.

Feeding and Swallowing Difficulties in Neonates: Developmental Physiology and Pathophysiology

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

Twenty years of quantitative instrumental measures of swallowing in children: a systematic review

Early identification and intervention has shown better health outcomes for children with dysphagia. Instrumental swallowing assessments are vital and have been a focus of dysphagia research in the last two decades. This systematic review explores published quantitative instrumental measures of swallowing in children. Five subject-related databases were searched to identify original scientific articles published in English, using instrumental quantitative measures of swallowing to study swallowing/feeding mechanism in children since 1998. Two thousand two hundred and two articles were found from the initial database search and 36 were included in the final qualitative synthesis following PRISMA guidelines. Selected studies showed great diversity in target population, phase/s of swallowing studied, instrumentation used (n = 10) and quantitative measures reported (n = 144). Videofluoroscopy and manometry have been studied most repeatedly. With less frequency, a variety of other instruments has been used to describe suck-swallow patterns and swallowing-related respiration. High-resolution manometry shows the greatest increase in publications with validated, reliable quantitative measures of pharyngeal and oesophageal pressures and timing. More recently, quantification of videofluoroscopy analysis has been a focus.Conclusion: A diverse range of quantitative measures of swallowing is available for children in the literature. However, further reliability and validity testing is needed. Opportunities for clinical application of these quantitative manometric and videofluoroscopic measures are restricted by limited normative comparisons and vast variability in published measures.What is known?• Instrumental swallowing assessments are reliable and accurate in diagnosing swallowing difficulties in children.• However, subjective interpretation of observational findings often questions the optimal use of instrumentation.What is new?• High-resolution manometry has shown promising progress with the development of quantitative objective swallow measures for children. While attempts to quantify video-fluoroscopic measures have been increased in the recent past.• A vast variety of instruments has been used to obtain quantitative and/or objective swallow measures of children, yet clinical application is still in progress.

Reduced Coordination of Hyolaryngeal Elevation and Bolus Movement in a Pig Model of Preterm Infant Swallowing

Preterm infants often have dysphagia. Because reducing lifetime cumulative exposure to radiation in the context of diagnosis and treatment is a continuing goal of all medical fields which use X-ray imaging, efforts exist to reduce reliance on the gold standard diagnostic tool for dysphagia, VFSS. Alternatives, such as video of external hyolaryngeal movement using video recordings of the anterior surface of the neck, must be evaluated and validated against videofluoroscopy, a task for which non-human animal models are appropriate. In this study, we tested the hypotheses that (1) swallows could be identified equally well from video of external hyolaryngeal movement and bolus movement in videofluoroscopy, and that (2) the two measures would be tightly temporally linked in both term and preterm infant pigs. We recorded 222 swallows in simultaneous and precisely synchronized high-speed videofluoroscopy and high-speed camera films of 4 preterm and 3 term infant pigs drinking milk from a bottle. In term pigs, the two measures consistently identified the same swallows in each image stream. However, in preterm pigs there was a high rate of false positives (~ 10% per feeding sequence) and false negatives (~ 27% per feeding sequence). The timing of hyolaryngeal elevation (external video) and bolus movement (videofluoroscopy) was correlated and consistent in terms pigs, but not in preterm pigs. Magnitude of hyolaryngeal elevation was less in preterm pig swallows than term pig swallows. Absence of epiglottal inversion in preterm pigs was not linked to variation in the timing of the two swallow events. Video of external hyolaryngeal movement, though a reliable swallow indicator in term infant pigs, was unreliable in preterm infant pigs. The coordination of swallowing events differs in preterm and term infant pigs. More research is needed into the distinctive biomechanics of preterm infant pigs.

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.