Physiology and pathophysiology of glottic reflexes and pulmonary aspiration: from neonates to adults

Fiberoptic Endoscopic Evaluation of Swallowing in the Breastfeeding Infant

OBJECTIVE

To demonstrate the importance of utilizing fiberoptic endoscopic evaluation of swallowing (FEES) when evaluating breastfeeding infants with suspected dysphagia. Failure to recognize and account for the fundamentally different physiology of the primarily breastfed infant can lead to false assumptions about the safety of breastfeeding in this understudied patient population.

METHODS

Case-series. The medical records of patients referred to an urban, university-based, pediatric hospital for FEES from February 2017 to October 2020 were reviewed. Their presenting symptoms, dysphagia severity, comorbidity, dysphagia workup, and management were analyzed. The standardized Dysphagia Outcome and Severity Scale was used to appraise dysphagia severity.

RESULTS

204 FEES exams were reviewed. 35 were conducted on breastfed infants. 34 of the 35 infants calmed for the FEES exam while breastfeeding. Cohorts were defined by a particular presenting sign (cough, laryngeal congestion, choking, and respiratory illness) and anatomical characteristic (laryngomalacia, vocal cord paralysis, aspiration, penetration, etc.) and then compared to all other exams. The average dysphagia score for all the exams was 2.37. Patients presenting with laryngeal congestion had an average dysphagia score of 2.81. There was no difference in dysphagia score based on comorbidities or anatomy.

CONCLUSIONS

FEES is the instrumental exam of choice when evaluating a primarily breastfed infant who has suspected dysphagia. The exam is well tolerated and provides accurate, objective information while accounting for this population's unique swallowing physiology. Primarily breastfed infants presenting with laryngeal congestion are more likely to have clinically worse dysphagia than those presenting with other clinical symptoms.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2803-2807, 2023.

Gastroesophageal reflux disease in children: What’s new right now?

Gastroesophageal reflux (GER) in children is very common and refers to the involuntary passage of gastric contents into the esophagus. This is often physiological and managed conservatively. In contrast, GER disease (GERD) is a less common pathologic process causing troublesome symptoms, which may need medical management. Apart from abnormal transient relaxations of the lower esophageal sphincter, other factors that play a role in the pathogenesis of GERD include defects in esophageal mucosal defense, impaired esophageal and gastric motility and clearance, as well as anatomical defects of the lower esophageal reflux barrier such as hiatal hernia. The clinical manifestations of GERD in young children are varied and nonspecific prompting the necessity for careful diagnostic evaluation. Management should be targeted to the underlying aetiopathogenesis and to limit complications of GERD. The following review focuses on up-to-date information regarding of the pathogenesis, diagnostic evaluation and management of GERD in children.

Computational Analysis of the Droplet-Stimulated Laryngeal Adductor Reflex in High-Speed Sequences

OBJECTIVES/HYPOTHESIS

The laryngeal adductor reflex (LAR) is an important protective mechanism of the airways. Its physiology is still not completely understood. The available methods for LAR evaluation offer limited reproducibility and/or rely on subjective interpretation. A new approach, termed Microdroplet Impulse Testing of the LAR (MIT-LAR), was recently introduced. Here, the LAR is elicited by a droplet and a laryngoscopic high-speed recording is acquired simultaneously. In the present work, image-processing algorithms for autonomous MIT-LAR sequence analysis were developed. This allowed the automated approximation of kinematic LAR parameters in humans.

STUDY DESIGN

Development and testing of computational methods.

METHODS

Computational image processing enabled the autonomous estimation of the glottal area, the glottal angle, and the vocal fold edge distance in MIT-LAR sequences. A suitable analytical representation of these glottal parameters allowed the extraction of seven relevant LAR parameters. The obtained values were compared to the literature.

RESULTS

A generalized logistic function showed the highest average goodness of fit among four different analytical approaches for each of the glottal parameters. Autonomous sequence analysis yielded bilateral LAR response latencies of (229 ± 116) ms and (182 ± 60) ms for cases of complete and incomplete glottal closure, respectively. The initial/average/maximum angular vocal fold adduction velocity was estimated at (157 ± 115) °s^-1 /(891 ± 516) °s^-1 /(929 ±  583) °s^-1 and (88 ± 53) °s^-1 /(421 ± 221) °s^-1 /(520 ± 238) °s^-1 for complete and incomplete glottal closure, respectively.

CONCLUSION

The automated extraction of LAR parameters from laryngoscopic high-speed sequences can potentially increase the objectiveness of optical LAR characterization and reduce the associated workload. The proposed methods may thus be helpful for future research on this vital reflex.

LEVEL OF EVIDENCE

NA Laryngoscope, 132:2412-2419, 2022.

Alveolar Ventilation-Targeted Versus Spontaneous/Timed Mode for Home Noninvasive Ventilation in Amyotrophic Lateral Sclerosis

BACKGROUND

Home noninvasive ventilation (NIV) is increasingly used in amyotrophic lateral sclerosis (ALS) to improve symptoms and survival. Our primary objective was to compare intelligent volume-assured pressure support (iVAPS) versus spontaneous/timed (S/T) modes regarding time to first change in ventilator parameters and the number of interventions over 6 months in subjects with ALS in a respiratory therapist (RT)-led program.

METHODS

In this study, 30 subjects with ALS meeting criteria for NIV initiation were randomized to iVAPS or S/T. NIV was initiated using standardized protocols targeting optimal tidal volume and comfort in a daytime session. Download data were recorded at 1 week and 1 and 6 months. Any changes in ventilator parameters were recorded.

RESULTS

Of the 30 subjects, 56.7% had bulbar onset ALS, 8 died, and 11 in each group completed the study. Median time to first parameter change was 33.5 (interquartile range [IQR] 7.7-96.0) d versus 41.0 (IQR 12.5-216.5) d for iVAPS versus S/T groups, respectively, (P = .48). The average number of RT interventions was similar between groups (1.1 ± 1.1 vs 0.9 ± 0.9 at 1 month, P = .72; 2.4 ± 2.1 vs 2.4 ± 2.3 at 6 months, P = .95, for iVAPS vs S/T, respectively). Adherence was significantly lower with iVAPS than S/T at 1 week but not at 1 or 6 months. Download parameters were similar between groups at 1 week and 6 months except for higher residual apnea-hypopnea index (AHI) and less spontaneously triggered breaths with iVAPS at 6 months.

CONCLUSIONS

The time to first change of parameters and the number of interventions at 6 months from NIV initiation were similar for the iVAPS and S/T modes in subjects with ALS. With iVAPS, adherence was lower transiently at NIV initiation, and the residual AHI was higher at 6 months. Alveolar ventilation-targeted NIV may require a longer adaptation period and result in greater upper-airway instability predominantly in patients with bulbar ALS.

Surgically Acquired Vocal Cord Palsy in Infants and Children with Congenital Heart Disease (CHD): Description of Feeding Outcomes

Impaired swallowing in infants can impact upon the ability to feed orally, often resulting in dependency on supplementary feeding. Such difficulties can lead to an increased burden of care and associated costs. The primary aim of this study was to investigate the impact of vocal cord palsy (VCP), acquired intraoperatively during cardiac surgery, on the feeding outcomes of infants at a tertiary metropolitan children's hospital. An additional aim was to obtain preliminary information on the impact of feeding difficulties in this group on the quality of life of parents and families. A review of 48 patients who had been referred to the speech pathology service was undertaken. Participants presented with heterogeneous cardiac diagnoses, and had an initial Videofluoroscopic Swallow Study (VFSS) at a median corrected age of 3.6 weeks. Sixty percent of participants presented with silent aspiration on VFSS. Thirty percent of participants required supplementary tube feeding more than 6 months post-surgery. Six percent of participants with poor feeding progress and persistent aspiration required further surgical intervention to support nutrition. Findings revealed no significant relationship between participant factors and the presence of feeding difficulties, however, infants with concomitant genetic and syndromic conditions were found to be most at-risk for long-term feeding difficulties. Analysis of informal parent questionnaire responses indicated parents experienced stress and anxiety after their child's discharge. This was noted in regard to their child's feeding, which impacts quality of life across a number of domains. Findings of this study highlight the importance of communicating the potential feeding difficulties to parents of at-risk infants prior to cardiac surgery. This study further highlighted the importance of routine post-operative otorhinolaryngology examinations following high-risk surgeries, as well as speech pathology management for all infants and children identified with VCP. Post-operative input from appropriately trained Speech Pathologists is vital in assisting parents to support and mitigate their child's difficulties through the provision of early intervention for feeding difficulties.

Developmental Functional Modules in Infant Vocalizations

Purpose Developmental functional modules (DFMs) are biological modules that are defined by their structural (morphological), functional, or developmental elements, and, in some cases, all three of these. This review article considers the hypothesis that vocal development in the first year of life can be understood in large part with respect to DFMs that characterize the speech production system. Method Literature is reviewed on relevant embryology, orofacial reflexes, craniofacial muscle properties, stages of vocal development, and related topics to identity candidates for DFMs. Results The following DFMs are identified and described: laryngeal, pharyngo-laryngeal, mandibular, velopharyngeal, labial complex, and lingual complex. These DFMs and their submodules, considered along with phenomena such as rhythmic movements, account for several well-documented features of vocal development in the first year of life. The proposed DFMs, rooted in embryologic, histologic, and kinematic properties, serve as low-dimensional control variables for the developing vocal tract. Each DFM is semi-autonomous but interacts with other DFMs to produce patterns of vocal behavior. Discussion Considered in relation to contemporary profiles and models of vocal development in the first year of life, DFMs have interpretive and explanatory value. DFMs complement other approaches in the study of infant vocalizations and are grounded in biology.

Comparing two airway management strategies for moderately sedated patients undergoing awake craniotomy: A single-blinded randomized controlled trial

BACKGROUND

In the monitored anesthesia care (MAC) setting for awake craniotomy (AC), maintaining airway patency in sedated patients remains challenging. This randomized controlled trial aimed to compare the validity of the below-epiglottis transnasal tube insertion (the tip of the tube placed between the epiglottis and vocal cords) and the nasopharyngeal airway (simulated by the above-epiglottis transnasal tube with the tip of the tube placed between the epiglottis and the free edge of the soft palate) with respect to maintaining upper airway patency for moderately sedated patients undergoing AC.

METHODS

Sixty patients scheduled for elective AC were randomized to receive below-epiglottis (n = 30) or above-epiglottis (n = 30) transnasal tube insertion before surgery. Moderate sedation was maintained in the pre- and post-awake phases. The primary outcome was the upper airway obstruction (UAO) remission rate (relieved obstructions after tube insertion/the total number of obstructions before tube insertion).

RESULTS

The UAO remission rate was higher in the below-epiglottis group [100% (12/12) vs 45% (5/11); P = .005]. The tidal volume values monitored through the tube were greater in the below-epiglottis group during the pre-awake phase (P < .001). End-tidal carbon dioxide (EtCO₂ ) monitored through the tube was higher in the below-epiglottis group at bone flap removal (P < .001). During the awake phase, patients' ability to speak was not impeded. No patient had serious complications related to the tube.

CONCLUSION

The below-epiglottis tube insertion is a more effective method to maintain upper airway patency than the nasopharyngeal airway for moderately sedated patients undergoing AC.

Clinical Management of Children with Oropharyngeal Aspiration - Physician Survey

Introduction: Pulmonary aspiration in infants and children is common, with 25% of the pediatric population reported to experience some type of nonspecific swallowing dysfunction. Diagnosing and managing oropharyngeal aspiration remain a challenging task due to the lack of distinguishing clinical or laboratory characteristics. We conducted a large, physician-based survey in an effort to determine the differences in the diagnosis and management of patients with oropharyngeal aspiration across different centers, using a quantitative online questionnaire. Methods: A survey was developed with the goal of understanding the physician demographics, diagnosis, management strategies, and the role of specialized centers for airway, voice, and swallowing disorders (also known as Aerodigestive Disease Centers). The questionnaire was sent to the pediatric membership of the American Thoracic Society. Results: A total of 136 questionnaires were completed and physicians from 42 different Aerodigestive Digestive Centers participated in the survey. Ninety-two percent of respondents believed that the evidence is unclear on the best methods for diagnosing lung disease related to oropharyngeal aspiration. Modified barium swallow (MBS) study and fiberoptic endoscopic evaluation of swallowing were the most useful studies in making the diagnosis of the oropharyngeal aspiration according to the participants. The majority of the participants preferred to repeat the feeding evaluations and MBS after the initial intervention. For children with suspected or confirmed aspiration, 68.6% of the respondents stated that they combine endoscopy and flexible and/or rigid bronchoscopy for further evaluation, while 27.1% preferred to perform the procedures individually at the discretion of each specialty provider. Inhaled corticosteroids were mostly prescribed if there was any component of bronchial hyperreactivity, and acid suppression therapy was primarily prescribed if there was a diagnosis or suspicion of gastroesophageal reflux disease. Empirical thickening of the feeds was not uniformly performed among the aerodigestive centers as a therapy method for the children with swallowing dysfunction with aspiration. Conclusion: In the survey, physicians mentioned about the importance of better guidelines for aspiration, the requirement of new diagnostic measures, the necessity of multicenter trials of sensitivity and specificity of current diagnostic tools, and developing a scoring system for reading the radiological studies for children with oropharyngeal aspiration.

Novel insight into the coordination between pelvic floor muscles and the glottis through ultrasound imaging: a pilot study

INTRODUCTION

Pelvic floor physical therapists have long utilized breathing cues with exercises and are beginning to incorporate vocalization tasks. To date, there have been no publications describing pelvic floor displacement during vocalization tasks. This study is a preliminary investigation into the changes in bladder shape distortion as a proxy for pelvic floor muscle displacement during respiratory and phonatory tasks.

METHODS

Bladders were imaged using two-dimensional ultrasound in standing position. Measurement consisted of a diagonal line from the most anterior-superior aspect of the bladder to the most inferior-posterior aspect of the bladder. Length was measured at baseline and maximum distortion for each task. The first two tasks cued pelvic floor muscles to contract and then strain. Subsequent tasks only cued glottis function. A linear regression tested correlation between bladder distortion response to glottis tasks and cued pelvic floor tasks. The hypothesis was that diagonal would shorten with contraction, lengthen with strain, and follow a similar pattern seen in respiration for phonation tasks.

RESULTS

Ten asymptomatic participants (5 men, 5 women) showed bladder diagonal shortening when cuing pelvic floor contraction for all participants and lengthening for 7 of the 10 participants when cued to strain the pelvic floor. The response of bladder length change was variable for glottis tasks, trending toward lengthening and significantly different in response to contraction.

CONCLUSIONS

When cuing pelvic floor to contract, healthy individuals showed shortening of bladder length and most lengthened during strain. When cuing phonation and respiration tasks, there was a tendency toward bladder lengthening.

An Airway Protection Program Revealed by Sweeping Genetic Control of Vagal Afferents

Sensory neurons initiate defensive reflexes that ensure airway integrity. Dysfunction of laryngeal neurons is life-threatening, causing pulmonary aspiration, dysphagia, and choking, yet relevant sensory pathways remain poorly understood. Here, we discover rare throat-innervating neurons (∼100 neurons/mouse) that guard the airways against assault. We used genetic tools that broadly cover a vagal/glossopharyngeal sensory neuron atlas to map, ablate, and control specific afferent populations. Optogenetic activation of vagal P2RY1 neurons evokes a coordinated airway defense program-apnea, vocal fold adduction, swallowing, and expiratory reflexes. Ablation of vagal P2RY1 neurons eliminates protective responses to laryngeal water and acid challenge. Anatomical mapping revealed numerous laryngeal terminal types, with P2RY1 neurons forming corpuscular endings that appose laryngeal taste buds. Epithelial cells are primary airway sentinels that communicate with second-order P2RY1 neurons through ATP. These findings provide mechanistic insights into airway defense and a general molecular/genetic roadmap for internal organ sensation by the vagus nerve.

Management of postoperative dysphagia after prosthetic laryngoplasty or arytenoidectomy

OBJECTIVE

To evaluate the efficacy of various treatments for dysphagia after laryngeal surgery.

STUDY DESIGN

Retrospective.

ANIMALS

Horses treated for dysphagia after laryngeal surgery.

METHODS

Medical records of horses treated for dysphagia after prosthetic laryngoplasty (PLP) or partial arytenoidectomy (PA) were reviewed. Signalment, prior surgery, preoperative videoendoscopic diagnosis, and surgical treatments were recorded. Short- and long-term follow-up were obtained. Chi-square and logistical regression were performed to correlate independent variables and outcomes.

RESULTS

Forty-four percent of horses with prior PLP and 88% of horses with prior PA had persistent resting dorsal displacement of the soft palate (DDSP). Vocal fold augmentation (VFA) as a single treatment was most commonly performed (n = 22), followed by laryngoplasty removal (LPR; n = 1). Fifteen horses received a combination of treatments: VFA (n = 15), LPR (n = 4), laryngeal tie-forward (LTF; n = 2), and esophageal release (n = 1). Short-term clinical outcomes were reported; 80% of horses treated with VFA (n = 35) had resolution of dysphagia, and 20% were improved. Among the 33 horses available to long-term follow-up, 31 (94%) returned to some level of work, and DDSP during work was reportedly resolved in 23 of 25 horses.

CONCLUSION

Vocal fold augmentation resulted in resolution of symptoms relating to dysphagia in 81% of horses. Twenty percent of horses treated with LPR had sustained resolution of dysphagia. A combination of LPR, VFA, LTF was performed in 18% of horses.

CLINICAL SIGNIFICANCE

Treatment options directed at altering laryngeal geometry and/or position of the larynx were successful in resolving 86% of dysphagia in horses previously regarded as very difficult to treat.

Breathing pattern during sequential swallowing in healthy adult humans

Sequential liquid swallowing is a common daily occurrence during which coordination of deglutition and breathing are highly regulated to avoid pulmonary aspiration and to maintain hematosis. We studied the effects of sequential water swallowing (SWS) at fixed swallowing rates and with regular succession of swallows on respiration in healthy subjects. Thirty-one normal adults (19 men, 12 women) with a mean age of 27.96 ± 3.68 yr were explored at rest and during SWS (at 12 and 24 swallows/min). Respiration was recorded by intranasal air pressure changes and timing of deglutition by an acoustic method. Oxygen saturation [arterial O₂ saturation from pulse oximetry ( SpO2 )] was monitored with a finger probe. During SWS, we determined the respiratory phase (inspiration or expiration) before and after each ingestion cycle (IC; period of sustained apnea including 1 or more swallows). We also measured inspiratory time (TI), expiratory time (TE), respiratory cycle duration (TT), respiratory rate (RR) and SpO2 at rest and during SWS. We showed that respiration was interrupted by sequential swallows determining a succession of ICs that were often preceded and followed by expiration. During SWS, TI decreased and TE increased compared with rest ( P < 0.01). However, TT, RR, and SpO2 did not change. It seems that the preferential coupling of swallowing with expiration during SWS is favored by an increase in TE to ensure airway protection, although the repetitive swallows, RR, and SpO2 were not altered during SWS. These data may be useful to study the effects of aging and pathological conditions on swallowing and breathing coordination during SWS. NEW & NOTEWORTHY Sequential water swallowing induces ingestion cycles that are often preceded and followed by expiration. Moreover, inspiratory time decreases and expiratory time increases during sequential swallowing compared with rest without changes in ventilatory cycle duration, respiratory rate, and oxygen saturation.

Pathogenesis of Lethal Aspiration Pneumonia in Mecp2-null Mouse Model for Rett Syndrome

Rett syndrome (RTT) is a neurodevelopmental disorder mainly caused by mutations in the gene encoding the transcriptional regulator Methyl-CpG-binding protein 2 (MeCP2), located on the X chromosome. Many RTT patients have breathing abnormalities, such as apnea and breathing irregularity, and respiratory infection is the most common cause of death in these individuals. Previous studies showed that MeCP2 is highly expressed in the lung, but its role in pulmonary function remains unknown. In this study, we found that MeCP2 deficiency affects pulmonary gene expression and structures. We also found that Mecp2-null mice, which also have breathing problems, often exhibit inflammatory lung injury. These injuries occurred in specific sites in the lung lobes. In addition, polarizable foreign materials were identified in the injured lungs of Mecp2-null mice. These results indicated that aspiration might be a cause of inflammatory lung injury in Mecp2-null mice. On the other hand, MeCP2 deficiency affected the expression of several neuromodulator genes in the lower brainstem. Among them, neuropeptide substance P (SP) immunostaining was reduced in Mecp2-null brainstem. These findings suggest that alteration of SP expression in brainstem may be involved in autonomic dysregulation, and may be one of the causes of aspiration in Mecp2-null mice.

Vocal palsy increases the risk of lower respiratory tract infection in low-risk, low-morbidity patients undergoing thyroidectomy for benign disease: A big data analysis

OBJECTIVES

Thyroidectomy is the commonest operation that places normally functioning laryngeal nerves at risk of injury. Vocal palsy is a major risk factor for dysphonia, dysphagia, and less commonly, airway obstruction. We investigated the association between post-thyroidectomy vocal palsy and long-term risks of pneumonia and laryngeal failure.

DESIGN

An N=near-all analysis of the English administrative dataset using a previously validated informatics algorithm to identify young and otherwise low-risk patients undergoing first-time elective thyroidectomy for benign disease. Information about age, sex, morbidities, social deprivation and post-operative and late complications were derived.

MAIN OUTCOME MEASURES

Between 2004 and 2012, 43 515 patients between the ages of 20 and 69 who had no history of cancer, neurological, or respiratory disease underwent elective total or hemithyroidectomy without concomitant or late neck dissection, parathyroidectomy or laryngotracheal surgery for benign thyroid disease for the first and only time. Information about age, sex, morbidities and in-hospital and late complications was recorded.

RESULTS

Mean age at surgery was 46±12. There was a strong female preponderance (85%), and most patients (89%) had no recorded Charlson comorbidities Most patients (65%) underwent hemithyroidectomy. Late vocal palsy was recorded in 449 (1.03%) patients, and its occurrence was an independent risk factor for emergency hospital readmission (n=7113; Hazard Ratio 1.52; 95% confidence interval 1.21-1.91), hospitalisation for lower respiratory tract infection (n=944; HR 2.04; 95% CI 1.07-3.75), dysphagia (n=564; HR 3.47; 95% CI 1.57-7.65) and gastrostomy/tracheostomy placement (n=80; HR 20.8; 95% CI 2.5-171.2). Independent risk factors for late vocal palsy were age, burden of morbidities, total thyroidectomy, post operative bleeding, male sex, and annual surgeon volume <30.

CONCLUSIONS

There is a significant association between post-thyroidectomy vocal palsy and long-term risks of hospital readmission, dysphagia, hospitalisation for lower respiratory tract infection, and gastrostomy/tracheostomy tube placement. This adds weight to the need, from a thyroid surgical perspective, to undertake universal post-thyroidectomy laryngeal surveillance as a minimum standard of care, with a focus on post-operative dysphagia and aspiration, and from a medical/respiratory perspective, to initiate investigations to identify occult vocal palsy in patients who present with pneumonia, who have a history of thyroid surgery.

Sleep-Disordered Breathing in Neuromuscular Disease: Diagnostic and Therapeutic Challenges

Normal sleep-related rapid eye movement sleep atonia, reduced lung volumes, reduced chemosensitivity, and impaired airway dilator activity become significant vulnerabilities in the setting of neuromuscular disease. In that context, the compounding effects of respiratory muscle weakness and disease-specific features that promote upper airway collapse or cause dilated cardiomyopathy contribute to various sleep-disordered breathing events. The reduction in lung volumes with neuromuscular disease is further compromised by sleep and the supine position, exaggerating the tendency for upper airway collapse and desaturation with sleep-disordered breathing events. The most commonly identified events are diaphragmatic/pseudo-central, due to a decrease in the rib cage contribution to the tidal volume during phasic rapid eye movement sleep. Obstructive and central sleep apneas are also common. Noninvasive ventilation can improve survival and quality of sleep but should be used with caution in the context of dilated cardiomyopathy or significant bulbar symptoms. Noninvasive ventilation can also trigger sleep-disordered breathing events, including ineffective triggering, autotriggering, central sleep apnea, and glottic closure, which compromise the potential benefits of the intervention by increasing arousals, reducing adherence, and impairing sleep architecture. Polysomnography plays an important diagnostic and therapeutic role by correctly categorizing sleep-disordered events, identifying sleep-disordered breathing triggered by noninvasive ventilation, and improving noninvasive ventilation settings. Optimal management may require dedicated hypoventilation protocols and a technical staff well versed in the identification and troubleshooting of respiratory events.

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.

The Role of Sleep in the Modulation of Gastroesophageal Reflux and Symptoms in NICU Neonates

BACKGROUND

Newborns sleep about 80% of the time. Gastroesophageal reflux disease is prevalent in about 10% of neonatal intensive care unit infants. Concurrent polysomnography and pH-impedance studies clarify the relationship of gastroesophageal reflux with sleep.

AIMS

To characterize spatiotemporal and chemical characteristics of impedance-positive gastroesophageal reflux and define symptom associations in sleep and wake states in symptomatic neonates. We hypothesized that frequency of impedance-positive gastroesophageal reflux events and their association with cardiorespiratory symptoms is greater during sleep.

METHODS

Eighteen neonates underwent concurrent polysomnography with a pH-impedance study. Impedance-positive gastroesophageal reflux events (weakly acidic or acidic) were categorized between sleep versus wake states: Symptom Index = number of symptoms with gastroesophageal reflux/total symptoms*100; Symptom Sensitivity Index = number of gastroesophageal reflux with symptoms/total gastroesophageal reflux*100; Symptom Association Probability = [(1 - probability of observed association between reflux and symptoms)*100]).

RESULTS

We analyzed 317 gastroesophageal reflux events during 116 hours of polysomnography. During wake versus sleep, respectively, the median (interquartile range) frequency of impedance-positive gastroesophageal reflux was 4.9 (3.1-5.8) versus 1.4 (0.7-1.7) events/hour (P < 0.001) and the proximal migration was 2.6 (0.8-3.3) versus 0.2 (0.0-0.9) events/hour (P < 0.001). The Symptom Index for cardiorespiratory symptoms for impedance-positive events was 22.5 (0-55.3) versus 6.1 (0-13), P = 0.04, whereas the Symptom Sensitivity Index was 9.1 (0-23.1) versus 18.4 (0-50), P = 0.04, although Symptom Association Probability was similar (P = 0.68).

CONCLUSIONS

Contrary to our hypothesis, frequency of gastroesophageal reflux in sleep is lower; however, spatiotemporal and chemical characteristics of gastroesophageal reflux and symptom-generation mechanisms are distinct. For cardiorespiratory symptoms during sleep, a lower Symptom Index entails evaluation for etiologies other than gastroesophageal reflux disease, a higher Symptom Sensitivity Index implies heightened esophageal sensitivity, and similar Symptom Association Probability indicates other mechanistic possibilities.

Pediatric Dysphagia: Physiology, Assessment, and Management

Infancy and childhood represent a time of unparalleled physical growth and cognitive development. In order for infants and children to reach their linear and neurological growth potential, they must be able to reliably and safely consume sufficient energy and nutrients. Swallowing difficulties (dysphagia) in pediatric populations can have a detrimental effect on dietary intake and, thus, growth and development. As a result, it is imperative to accurately identify and appropriately manage dysphagia in pediatric populations. This article provides an overview of dysphagia in children, as well as common causes of childhood swallowing difficulties, populations at risk for pediatric dysphagia, techniques used to assess swallowing in pediatric patients, and the current treatment options available for infants and children with dysphagia.

Whats special in a child's larynx?

What's special in a child's larynx? Many of us know only a few specialties of the pediatric larynx, but there are much more features, which are unique and often not highlighted. To understand the pediatric larynx, we have reviewed the development, the functions in-utero and new born period and peculiarities.

Laryngotracheal separation in an infant with severe dysgenesis of the larynx

OBJECTIVES/HYPOTHESIS

We describe management of an infant with chronic aspiration as a result of severe and rarely described laryngeal dysgenesis.

RESULTS

A neonate with severe maldevelopment of the laryngeal structures required tracheostomy for respiratory distress on day-of-life 1, but the patient continued to have aspiration pneumonias. After failing to improve with conservative measures, the infant underwent laryngotracheal separation (LTS), which was successful in preventing aspiration. The patient has had no further pneumonias.

CONCLUSIONS

The presented case illustrates that LTS may be considered a safe and effective initial treatment option for chronic aspiration in select infants with severe dysgenesis of the larynx.

The Pediatric Lung and Aspiration

This article offers an over view of lung development, physiology, and evaluation of lung damage due to aspiration. Considerations specific to pediatric patients are discussed.

Practice Variance, Prevalence, and Economic Burden of Premature Infants Diagnosed With GERD

OBJECTIVE

To determine the practice variance, prevalence, and economic burden of clinically diagnosed gastroesophageal reflux disease (GERD) in preterm infants.

METHODS

Applying a retrospective cohort study design, we analyzed data from 18 567 preterm infants of 22 to 36 weeks' gestation and >400 g birth weight from the NICUs of 33 freestanding children's hospitals in the United States. GERD prevalence, comorbidities, and demographic factors were examined for their association with average length of stay (LOS) and hospitalization cost.

RESULTS

Overall, 10.3% of infants received a diagnosis of GERD (95% confidence interval [CI]: 9.8-10.7). There was a 13-fold variation in GERD rates across hospitals (P < .001). GERD diagnosis was significantly (P < .05) associated with bronchopulmonary dysplasia and necrotizing enterocolitis, as well as congenital anomalies and decreased birth weight. GERD diagnosis was associated with $70 489 (95% CI: 62 184-78 794) additional costs per discharge and 29.9 additional days in LOS (95% CI: 27.3-32.5).

CONCLUSIONS

One in 10 of these premature NICU infants were diagnosed with GERD, which is associated with substantially increased LOS and elevated costs. Better diagnostic and management strategies are needed to evaluate reflux-type symptoms in this vulnerable NICU population.

Aspiration and Swallowing Dysfunction in Pediatric Patients

Early identification and management of aspiration associated with oral intake will help contribute to the best possible outcome for infants and children who have airway protection issues with swallowing. Though the incidence and prevalence of aspiration specifically related to swallowing dysfunction across medical conditions in the pediatric population is unknown, there is accumulating evidence of swallowing-related aspiration in infants and children with diagnoses that include structural abnormalities of the upper airway, central nervous system abnormalities, and progressive neurological disease. Chronic aspiration is associated with compromised respiratory health, progressive lung disease, bronchiectasis, and respiratory failure; thus, early detection and appropriate management is crucial. Determining the etiology and effect of aspiration is complex, and multiple evaluations are often required. This article will focus on instrumental studies of swallowing physiology used in the diagnosis and management of swallowing dysfunction and aspiration. Therapeutic strategies to improve airway protection during swallowing will also be described.