An overview of reflux-associated disorders in infants: apnea, laryngospasm, and aspiration

Inflammatory Causes of Dysphagia in Children

Gastroesophageal reflux (GER) and eosinophilic esophagitis (EoE) are the most common inflammatory causes of pediatric dysphagia, but several other less prevalent conditions should be considered. These conditions can affect one or several aspects of the swallowing process. In some inflammatory conditions dysphagia may be an early symptom. Esophagoscopy and instrumental swallow studies are often needed to determine the underlying diagnosis and best treatment plan. In some inflammatory conditions dysphagia can portend a worse outcome and need for more aggressive treatment of the underlying condition. Consultations with speech language pathology, gastroenterology, dietetics, allergy/immunology and/or rheumatology are often needed to optimize management.

Mechanisms and prevention of acid reflux induced laryngospasm in seizing rats

OBJECTIVE

Recent animal work and limited clinical data have suggested that laryngospasm may be involved in the cardiorespiratory collapse seen in sudden unexpected death in epilepsy (SUDEP). In previous work, we demonstrated in an animal model of seizures that laryngospasm and sudden death were always preceded by acid reflux into the esophagus. Here, we expand on that work by testing several techniques to prevent the acid reflux or the subsequent laryngospasm.

METHODS

In urethane anesthetized Long Evans rats, we used systemic kainic acid to acutely induce seizure activity. We recorded pH in the esophagus, respiration, electrocorticography activity, and measured the liquid volume in the stomach postmortem. We performed the following three interventions to attempt to prevent acid reflux or laryngospasm and gain insights into mechanisms: fasting animals for 12 h, severing the gastric nerve, and electrical stimulation of either the gastric nerve or the recurrent laryngeal nerve.

RESULTS

Seizing animals had significantly more liquid in their stomach. Severing the gastric nerve and fasting animals significantly reduced stomach liquid volume, subsequent acid reflux, and sudden death. Laryngeal nerve stimulation can reverse laryngospasm on demand. Seizing animals are more susceptible to death from stomach acid-induced laryngospasm than nonseizing animals are to artificial acid-induced laryngospasm.

SIGNIFICANCE

These results provide insight into the mechanism of acid production and sudden obstructive apnea in this model. These techniques may have clinical relevance if this model is shown to be similar to human SUDEP.

Gastroesophageal Reflux Poses a Potential Risk for Late Complications of Bronchopulmonary Dysplasia: A Prospective Cohort Study

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common respiratory disorder in extremely low birth weight infants. Although most symptoms of BPD improve, some late complications exist, even with regular treatment. Gastroesophageal reflux (GER), also common in extremely premature infants, may be related to many cardiorespiratory symptoms. However, the potential of GER as a risk factor for late complications associated with BPD is still unclear.

RESEARCH QUESTION

The goal of this study was to determine if GER increases the risk of late complications of BPD in infants.

STUDY DESIGN AND METHODS

A multicenter prospective cohort of 131 infants (79 male subjects, 52 female subjects) with BPD was enrolled. The development of late complications was assessed over an 18-month follow-up period. Twenty-four-hour pH-multichannel intraluminal impedance and gastric sodium concentrations were analyzed in all infants at 36 weeks' postmenstrual age and at the last interview. Prevalence and risk factors of late complications of BPD were analyzed by using forward logistic regression.

RESULTS

The prevalence of late complications in BPD infants was 63.79% and included respiratory symptoms (49.14%), vomiting (38.79%), retinopathy of prematurity (25.86%), hypoxic-ischemic injury (3.45%), rehospitalization (26.72%), and sudden death (0.86%). Respiratory diseases constituted the most frequent complication. The prevalence of GER in BPD was 42.24% and included acid GER (18.10%) and duodenogastroesophageal reflux (DGER; 24.14%). Risk factors for respiratory symptoms were gestational age ≤ 30 weeks (OR, 3.213; 95% CI, 1.221-8.460), birth weight < 1,500 g (OR, 2.803; 95% CI, 1.014-7.749), invasive ventilation > 7 days (OR, 4.952; 95% CI, 1.508-16.267), acid GER (OR, 4.630; 95% CI, 1.305-16.420), and DGER (OR, 5.588; 95% CI, 1.770-17.648). Infants with BPD and DGER were more prone to late complications than those with acid GER or no reflux.

INTERPRETATION

The prevalence of late complications is high in infants with BPD. GER (and in particular, DGER) poses a tentative risk for these late complications.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03014453; URL: www.clinicaltrials.gov.

Home Videos as a Cost-Effective Tool for the Diagnosis of Paroxysmal Events in Infants: Prospective Study

Background

The diagnosis of paroxysmal events in infants is often challenging. Reasons include the child’s inability to express discomfort and the inability to record video electroencephalography at home. The prevalence of mobile phones, which can record videos, may be beneficial to these patients. In China, this advantage may be even more significant given the vast population and the uneven distribution of medical resources.

Objective

The aim of this study is to investigate the value of mobile phone videos in increasing the diagnostic accuracy and cost savings of paroxysmal events in infants.

Methods

Clinical data, including descriptions and home videos of episodes, from 12 patients with paroxysmal events were collected. The investigation was conducted in six centers during pediatric academic conferences. All 452 practitioners present were asked to make their diagnoses by just the descriptions of the events, and then remake their diagnoses after watching the corresponding home videos of the episodes. The doctor’s information, including educational background, profession, working years, and working hospital level, was also recorded. The cost savings from accurate diagnoses were measured on the basis of using online consultation, which can also be done easily by mobile phone. All data were recorded in the form of questionnaires designed for this study.

Results

We collected 452 questionnaires, 301 of which met the criteria (66.6%) and were analyzed. The mean correct diagnoses with and without videos was 8.4 (SD 1.7) of 12 and 7.5 (SD 1.7) of 12, respectively. For epileptic seizures, mobile phone videos increased the mean accurate diagnoses by 3.9%; for nonepileptic events, it was 11.5% and both were statistically different (P=.006 for epileptic events; P<.001 for nonepileptic events). Pediatric neurologists with longer working years had higher diagnostic accuracy; whereas, their working hospital level and educational background made no difference. For patients with paroxysmal events, at least US $673.90 per capita and US $128 million nationwide could be saved annually, which is 12.02% of the total cost for correct diagnosis.

Conclusions

Home videos made on mobile phones are a cost-effective tool for the diagnosis of paroxysmal events in infants. They can facilitate the diagnosis of paroxysmal events in infants and thereby save costs. The best choice for infants with paroxysmal events on their initial visit is to record their events first and then show the video to a neurologist with longer working years through online consultation.

Aspiration After Congenital Heart Surgery

Dysphagia and vocal cord dysfunction are frequent complications after congenital heart surgery. Both are risk factors for aspiration, which can lead to pneumonia, progressive lung disease, and respiratory arrest. A protocol was implemented to promote early detection of aspiration in a high-risk cohort of patients. Retrospective data were collected on all patients under 120 days old who underwent the Norwood procedure, aortic arch repair, Blalock-Taussig shunt placement, or cervical cannulation for extracorporeal membrane oxygenation from 10/2012 to 05/2016 at a single institution. Patients underwent an assessment of symptoms, fiberoptic endoscopic evaluation of swallowing (FEES), and modified barium swallow (MBS) study in the postoperative period prior to initiating oral feeds. Patients with and without aspiration were compared. Of the 96 patients included in the study, one-third (33%) of patients had evidence of vocal cord dysfunction by FEES and just over half (51%) had evidence of aspiration by FEES or MBS. Most (73%) of the patients with aspiration were asymptomatic and a majority (53%) of patients with aspiration had normal vocal cord function. Aspiration is common after congenital heart surgery, and an assessment of vocal cord or swallow function in isolation may lead to underdiagnosis. A comprehensive protocol including MBS and FEES is necessary for the early detection of vocal cord dysfunction and aspiration and may prevent adverse outcomes in high-risk postoperative patients.

Acoustic and Perceptual Profiles of Swallowing Sounds in Children: Normative Data for 4-36 Months from a Cross-Sectional Study Cohort

Limited data on cervical auscultation (CA) sounds during the transitional feeding period of 4-36 months in healthy children exist. This study examined the acoustic and perceptual parameters of swallowing sounds in children aged 4-36 months over a range of food and fluid consistencies. Using CA, swallowing sounds were recorded from a microphone as children ate or drank. Acoustic parameters of duration, peak frequency and peak intensity were determined. Perceptual parameters of swallowing/breath sounds heard pre-, during and post-swallow were rated ('present', 'absent', 'cannot be determined') for each texture. 74 children (35 males; mean age = 17.1 months [SD 10.0]) demonstrated mean swallow durations of <1 s. Increasing age correlated to reduced peak frequency on puree (r = -0.48, 95 % CI -0.66, -0.24). Age correlated to peak amplitude when swallowing puree (r = 0.27, 95 % CI 0.02, 0.49), chewable solids (r = 0.31, 95 % CI 0.02, 0.56) and thin fluids (r = 0.48, 95 % CI 0.27, 0.64). The bolus transit sound was present in all swallows. A majority of children had normal breathing sounds and coordinated swallows. A swallow duration of <1 s and the presence of a quick bolus transit sound with normal breathing sounds were found in healthy children. The normative data reported in this study provide a platform for future comparison to abnormal swallowing sounds in children.

Aspirating and Nonaspirating Swallow Sounds in Children

Background:

Cervical auscultation (CA) may be used to complement feeding/swallowing evaluations when assessing for aspiration. There are no published pediatric studies that compare the properties of sounds between aspirating and nonaspirating swallows.

Aim:

To establish acoustic and perceptual profiles of aspirating and nonaspirating swallow sounds and determine if a difference exists between these 2 swallowing types.

Methods:

Aspiration sound clips were obtained from recordings using CA simultaneously undertaken with videofluoroscopic swallow study. Aspiration was determined using the Penetration-Aspiration Scale. The presence of perceptual swallow/breath parameters was rated by 2 speech pathologists who were blinded to the type of swallow. Acoustic data between groups were compared using Mann Whitney U-tests, while perceptual differences were determined by a test of 2 proportions. Combinations of perceptual parameters of 50 swallows (27 aspiration, 23 no aspiration) from 47 children (57% male) were statistically analyzed using area under a receiver operating characteristic (aROC), sensitivity, specificity, and positive and negative predictive values to determine predictors of aspirating swallows.

Results:

The combination of post-swallow presence of wet breathing and wheeze and absence of GRS and normal breathing was the best predictor of aspiration (aROC = 0.82, 95% CI, 0.70-0.94). There were no significant differences between these 2 swallow types for peak frequency, duration, and peak amplitude.

Conclusion:

Our pilot study has shown that certain characteristics of swallow obtained using CA may be useful in the prediction of aspiration. However, further research comparing the acoustic swallowing sound profiles of normal children to children with dysphagia (who are aspirating) on a larger scale is required.

Brief Resolved Unexplained Events (Formerly Apparent Life-Threatening Events) and Evaluation of Lower-Risk Infants

This is the first clinical practice guideline from the American Academy of Pediatrics that specifically applies to patients who have experienced an apparent life-threatening event (ALTE). This clinical practice guideline has 3 objectives. First, it recommends the replacement of the term ALTE with a new term, brief resolved unexplained event (BRUE). Second, it provides an approach to patient evaluation that is based on the risk that the infant will have a repeat event or has a serious underlying disorder. Finally, it provides management recommendations, or key action statements, for lower-risk infants. The term BRUE is defined as an event occurring in an infant younger than 1 year when the observer reports a sudden, brief, and now resolved episode of ≥1 of the following: (1) cyanosis or pallor; (2) absent, decreased, or irregular breathing; (3) marked change in tone (hyper- or hypotonia); and (4) altered level of responsiveness. A BRUE is diagnosed only when there is no explanation for a qualifying event after conducting an appropriate history and physical examination. By using this definition and framework, infants younger than 1 year who present with a BRUE are categorized either as (1) a lower-risk patient on the basis of history and physical examination for whom evidence-based recommendations for evaluation and management are offered or (2) a higher-risk patient whose history and physical examination suggest the need for further investigation and treatment but for whom recommendations are not offered. This clinical practice guideline is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient outcomes, support implementation, and provide direction for future research. Each key action statement indicates a level of evidence, the benefit-harm relationship, and the strength of recommendation.

Underlying Mechanisms in Episodic Laryngeal Breathing Disorders

The study and management of episodic laryngeal breathing disorders (ELBD)—characterized by paradoxical laryngeal movement patterns and dyspnea—has traditionally focused on clinical presentation of these conditions. However, the underlying mechanisms driving these entities are largely unknown. This article provides a review of potential underlying mechanisms driving clinical expression in ELBD and suggests approaches to the future study of ELBD etiology.

Vocal cord dysfunction: a review

Vocal cord dysfunction (VCD) is a term that refers to inappropriate adduction of the vocal cords during inhalation and sometimes exhalation. It is a functional disorder that serves as an important mimicker of asthma. Vocal cord dysfunction can be difficult to treat as the condition is often underappreciated and misdiagnosed in clinical practice. Recognition of vocal cord dysfunction in patients with asthma-type symptoms is essential since missing this diagnosis can be a barrier to adequately treating patients with uncontrolled respiratory symptoms. Although symptoms often mimic asthma, the two conditions have certain distinct clinical features and demonstrate specific findings on diagnostic studies, which can serve to differentiate the two conditions. Moreover, management of vocal cord dysfunction should be directed at minimizing known triggers and initiating speech therapy, thereby minimizing use of unnecessary asthma medications. This review article describes key clinical features, important physical exam findings and commonly reported triggers in patients with vocal cord dysfunction. Additionally, this article discusses useful diagnostic studies to identify patients with vocal cord dysfunction and current management options for such patients.

The nasogastric tube syndrome in infants

This series of three patients is the first description of the presentation, clinical course, and endoscopic findings of nasogastric tube-related airway distress, or nasogastric tube syndrome, in infants. We identify key differences in disease features from those described in adults, based on our literature review. Specifically, infant nasogastric tube syndrome presented as significant respiratory distress and postcricoid inflammation without vocal fold immobility. Symptoms resolved more quickly (mean±SD, 2±1 days) than reported in adults. We suggest that nasogastric tube syndrome should be considered in infants with otherwise unexplained respiratory distress, even in the absence of impaired vocal fold mobility.

Contemporary topics in pediatric pulmonology for the primary care clinician

Disorders of the respiratory system are commonly encountered in the primary care setting. The presentations are myriad and this review will discuss some of the more intriguing or vexing disorders that the clinician must evaluate and treat. Among these are dyspnea, chronic cough, chest pain, wheezing, and asthma. Dyspnea and chest pain have a spectrum ranging from benign to serious, and the ability to effectively form a differential diagnosis is critical for reassurance and treatment, along with decisions on when to refer for specialist evaluation. Chronic cough is one of the more common reasons for primary care office visits, and once again, a proper differential diagnosis is necessary to assist the clinician in formulating an appropriate treatment plan. Infant wheezing creates much anxiety for parents and accounts for a large number of office visits and hospital admissions. Common diagnoses and evaluation strategies of early childhood wheezing are reviewed. Asthma is one of the most common chronic diseases of children and adults. The epidemiology, diagnosis, evaluation, treatment, and the patient/parent education process will be reviewed. A relatively new topic for primary care clinicians is cystic fibrosis newborn screening. The rationale, methods, outcomes, and implications will be reviewed. This screening program may present some challenges for clinicians caring for newborns, and an understanding of the screening process will help the clinician communicate effectively with parents of the patient.

Vocal cord dysfunction

Vocal cord dysfunction (VCD), generally characterized by paradoxical closure of the vocal cords during inspiration, is a common mimicker of asthma and of other conditions that cause upper airway obstruction. As a result, it is frequently overlooked and often misdiagnosed, resulting in administration of excessive medications or other unnecessary interventions, with resultant morbidity. This article explores the clinical features, proposed causes, diagnostic considerations, and management of VCD, as well as some differences between VCD and asthma that can aid in differentiating these two diagnoses in the clinical setting.

Anti-reflux procedure for difficult-to-treat asthmatic children, case report and literature review

Gastroesophageal reflux disease (GERD) is a commonly encountered condition in children, which at times causes respiratory distress, such as asthmatic symptoms, and results in serious morbidity and even mortality. The complexity is sometimes so obscure, that it can cause paradoxical diagnoses and treatment. Here we present two cases of children with difficult-to-treat asthmatic symptoms, which were eventually found to be related to GERD. The two children were treated with anti-reflux procedures and both became symptom free. Literature was also reviewed to shed a light into this complex disease.

Addressing Nutrient Density in the Context of the Use of Thickened Liquids in Dysphagia Treatment

Thickening liquids has become a standard of practice for managing children with oropharyngeal dysphagia. A variety of commercial products have been developed from guar gum, xanthan gums, and modified corn starch. Practitioners and families are also trying to thicken liquids with available foods, such as infant rice cereal, yogurt, strained baby foods, and instant potato flakes. Throughout this process little consideration is given to the impact of the use of different thickeners on the nutrient density of human milk, formula, or other beverages. Various fluids were thickened by the author using different products to achieve National Dysphagia Diet nectar-like, or honey-like consistencies. Nutrient analysis of the calorie effect of the thickeners was calculated using the USDA Agriculture Research Service Nutrient database, manufacturer information, and displacement factors to evaluate the effects on calories per ounce of the thickened fluids. Considerations of thickener choice on other nutrients are discussed, including potential for toxicity of nutrient loads with specific thickeners. No one thickener is appropriate for all patients, but the characteristics of the various thickeners need to be understood. The assessment of the individual patient by an interdisciplinary team, including a registered dietitian should determine the patient’s specific needs before recommending a thickener.

Prolonged bedtime bottle feeding and respiratory symptoms in infants

Background

Infants with chronic respiratory symptoms should be evaluated thoroughly because there are various causes which are different from those of children and adolescents.

Objective

This study was designed to investigate the relationship between chronic respiratory symptoms and bedtime bottle feeding in infants after the age of 6 months.

Methods

We conducted a prospective study that included 44 infants who presented with respiratory symptoms for more than 8 weeks and also had been bottle-fed during bedtime even after 6 months of age. The infants were divided into 2 groups; infants who discontinued bedtime bottle feeding and those who did not. Respiratory symptom scores were graded with a four-point scale at 0, 1, 2 and 3 months, and were compared between the 2 groups.

Results

Twenty eight infants (63.6%) stopped being bottle-fed during bedtime and 16 infants (36.4%) were still bottle-fed. The respiratory symptom scores were significantly decreased in infants who stopped bedtime bottle feeding (p = 0.0003).

Conclusion

It is suggested that prolonged bedtime bottle feeding might be one of the causes of chronic respiratory symptoms in infants.

Relationship between sleep and acid gastro-oesophageal reflux in neonates

The aim of the present study was to investigate the impact of gastro-oesophageal acid reflux on sleep in neonates and, reciprocally, the influence of wakefulness (W) and sleep stages on the characteristics of the reflux (including the retrograde bolus migration of oesophageal acid contents). The pH and multichannel intraluminal impedance were measured during nocturnal polysomnography in 25 infants hospitalised for suspicion of gastro-oesophageal reflux. Two groups were constituted according to whether or not the infants displayed gastro-oesophageal reflux (i.e. a reflux group and a control group). There were no differences between the reflux and control groups in terms of sleep duration, sleep structure and sleep state change frequency. Vigilance states significantly influenced the gastro-oesophageal reflux pattern: the occurrence of gastro-oesophageal reflux episodes was greater during W (59 ± 32%) and active sleep (AS; 35 ± 30%) than during quiet sleep (QS; 6 ± 11%), whereas the mean duration of gastro-oesophageal reflux episodes was higher in QS than in W and AS. The percentage of retrograde bolus migrations of distal oesophageal acid content was significantly higher in AS (62 ± 26%) than in W (42 ± 26%) and QS (4.5 ± 9%). In neonates, gastro-oesophageal reflux occurred more frequently during W, whereas the physiological changes associated with sleep state increase the physiopathological impact of the gastro-oesophageal reflux. The duration of oesophagus-acid contact was greater during sleep; AS facilitated the retrograde migration of oesophageal acid content, and QS was characterised by the risk of prolonged acid mucosal contact.

Pepsin measured in induced sputum--a test for pulmonary aspiration in children?

PURPOSE

The purpose of this study was to investigate if pepsin measured in sputum is a useful marker of pulmonary aspiration secondary to gastroesophageal reflux (GER) in children. It is possible that the induced sputum procedure could cause GER and invalidate the results. The hypothesis stated that healthy children (those without history of respiratory or gastroesophageal symptoms) would not have pepsin detected in induced sputum.

METHODS

Children attending surgical outpatients in the Royal Belfast Hospital for Sick Children (Belfast, Northern Ireland) were recruited. After spirometry, sputum was obtained by induction with hypertonic 3% saline. Spirometry was repeated, and complications were noted. An "in-house" enzyme-linked immunosorbent assay was used to measure pepsin concentration in sputum. The lower limit of detection of pepsin was 1.19 ng/mL.

RESULTS

Children (n = 21) aged 4 to 16 years were recruited. Twenty children completed the study. No adverse effects were reported. Pepsin was detected in 17 (85%) of 20 sputum samples.

CONCLUSIONS

The act of sputum induction appears to induce physiologic GER in a healthy childhood population. The analysis of pepsin in sputum obtained by sputum induction is therefore not useful in the investigation of reflux-related respiratory disease.

Aspiration lung disease

The term aspiration lung disease describes several clinical syndromes, with massive aspiration and chronic lung aspiration being at two extremes of the clinical spectrum. Over the years, significant advances have been made in understanding the mechanisms underlying dysphagia, gastroesophageal function, and airway protective reflexes and new diagnostic techniques have been introduced. Despite this, characterizing the presence or absence of aspiration, and under what circumstances a child might be aspirating what, is extremely challenging. Many children are still not adequately diagnosed or treated for aspiration until permanent lung damage has occurred. A multidisciplinary approach is mandatory for a correct diagnosis in addition to timely and appropriate care.

Lipid laden macrophage indices and reflux finding score in canine gastroesophageal reflux model

Laryngeal exposure to acid and aspiration of gastric contents may lead to severe respiratory disorders. This study utilizes the canine model of Gastroesophageal reflux (GER) to identify whether lower esophageal dysfunction is associated with upper and lower airway pathology.

MATERIALS AND METHODS

Five mongrel dogs underwent GER-creating surgery (partial cardiomyectomy). Laryngeal reflux finding score (RFS), lipid-laden macrophage index (LLMI) and BAL fluid cell differential were obtained before and after surgery.

RESULTS

Partial cardiomyectomy in dogs significantly increased the Reflux index (RI) from 0.38 +/- 0.21% to 7.56 +/- 2.89% (P = 0.048), the duration of the longest reflux episode (DLRE) from 1.22 +/- 1.19 min to 66.2 +/- 42.03 min postoperatively (P = 0.049) and the total number of episodes in 24 hr from 2.06 +/- 1.03 to a postoperative value of 19.24 +/- 4.79. There was no statistically significant change in values for RFS, LLMI, and BAL fluid cell differential after the induction of GER.

CONCLUSIONS

Acid reflux to the proximal esophagus of this animal model did not cause laryngeal exposure to acid or aspiration of gastric content. The results of this study suggest that presence of GER, secondary to lower esophageal dysfunction is not necessarily associated with upper and lower airway pathology.

Evaluation of swallowing in children with vomiting after feeding

Vomiting after feeding is a symptom of gastroesophageal reflux (GER) and of eosinophilic esophagitis (EE), which are considered to be a cause of infant feeding disorder. The objective of the present study was to evaluate swallowing in children with feeding disorder manifested by vomiting after feeding. Using clinical and videofluoroscopic methods we studied the swallowing of 37 children with vomiting after feeding (mean age=15.4 months), and of 15 healthy children (mean age=20.5 months). In the videofluoroscopic examination the children swallowed a free volume of milk and 5 ml of mashed banana, both mixed with barium sulfate. We evaluated five swallows of liquid and five swallows of paste. The videofluoroscopic examination was recorded at 60 frames/s. Patients had difficulty during feeding, pneumonia, respiratory distress, otitis, and irritability more frequently than controls. During feeding, children with vomiting, choke were irritable, and refused food more frequently than controls, and during the videofluoroscopic examination the patients had more backward movement of the head than controls for both the liquid and paste boluses. There was no difference in the timing of oral swallowing transit, pharyngeal swallowing transit, or pharyngeal clearance between patients and controls. We conclude that children with vomiting after feeding may have difficulties in accepting feeding, although they have no alteration of oral and pharyngeal phases of swallowing.

Esophago-glottal closure reflex in human infants: a novel reflex elicited with concurrent manometry and ultrasonography

BACKGROUND AND AIMS

Our aims were to identify and characterize the glottal response to esophageal mechanostimulation in human infants. We tested the hypotheses that glottal response is related to the type of esophageal peristaltic response, stimulus volume, and respiratory phase.

METHODS

Ten infants (2.8 kg, SD 0.5) were studied at 39.2 wk (SD 2.4). Esophageal manometry concurrent with ultrasonography of the glottis (USG) was performed. The sensory-motor characteristics of mechanostimulation-induced esophago-glottal closure reflex (EGCR, adduction of glottal folds upon esophageal provocation) were identified. Mid-esophageal infusions of air (N = 41) were given and the temporal relationships of glottal response with deglutition, secondary peristalsis (SP), and the respiratory phase were analyzed using multinomial logistic regression models.

RESULTS

The frequency occurrence of EGCR (83%) was compared (P < 0.001) with deglutition (44%), SP (34%), and no esophageal responses (22%). The odds ratios (OR, 95% CI) for the coexistence of EGCR with SP (0.4, 0.06-2.2), deglutition (1.9, 0.1-26), and no response (1.9, 0.4-9.0) were similar. The response time for esophageal reflexes was 3.8 (SD 1.8) s, and for EGCR was 0.4 (SD 0.3) s (P < 0.001). Volume-response relationship was noted (1 mL vs 2 mL, P < 0.05). EGCR was noted in both respiratory phases; however, EGCR response time was faster during expiration (P < 0.05).

CONCLUSION

The occurrence of EGCR is independent of the peristaltic reflexes or the respiratory phase of infusion. The independent existence of EGCR suggests a hypervigilant state of the glottis to prevent retrograde aspiration during GER events.

Aspiration of gastric contents in sudden infant death syndrome without cardiopulmonary resuscitation

OBJECTIVES

(1) To compare demographic profiles among sudden infant death syndrome (SIDS) infants with or without gastric aspiration, for whom cardiopulmonary resuscitation (CPR) had not been attempted; (2) to review the severity and potential significance of aspiration in those SIDS cases; and (3) to assess the risk of supine sleep position with regard to gastric aspiration.

STUDY DESIGN

Retrospective review of records and microscopic slides for all postneonatal SIDS cases (29 to 365 days of age) accessioned by the San Diego County Medical Examiner from 1991 to 2004.

RESULTS

Ten (14%) of 69 cases of SIDS infants who had not undergone CPR before autopsy revealed microscopic evidence of gastric aspiration into the distal lung; this group was not otherwise clinically or pathologically different from cases of SIDS infants without aspiration. Similar proportions of infants were found supine or prone, regardless of gastric aspiration.

CONCLUSIONS

Gastric aspiration is not uncommon in infants dying of SIDS, and supine sleep position does not increase its risk. Gastric aspiration may be a terminal event that some infants, representing a subset of SIDS cases, cannot overcome.

Pulmonary aspiration shown by scintigraphy in gastroesophageal reflux-related respiratory disease

OBJECTIVES

Gastroesophageal reflux (GER) may underlie respiratory manifestations via vagally mediated airway hyperresponsiveness or microaspiration, and intraesophageal pH monitoring is generally used to identify GER in patients with such manifestations. We aimed to establish the frequency of retrograde pulmonary aspiration in patients with unexplained respiratory manifestations.

METHODS

Fifty-one patients with refractory respiratory symptoms (cough, n = 18; pneumonia, n = 14; apnea, n = 8; asthma, n = 7; and laryngitis, n = 4) were prospectively evaluated. They underwent 24-h intraesophageal pH monitoring and gastroesophageal 99Tc scintigraphy with lung scan 18 to 20 h after the test meal.

RESULTS

Thirteen of 51 patients (25.5%) had abnormal intraesophageal pH study results (mean reflux index, 11.3%; range, 6.5 to 50%); and in 25 of 51 patients (49%), overnight scintigraphy showed pulmonary aspiration. Nineteen of these 25 patients had entirely normal pH study results, whereas 6 of 13 patients with abnormal pH study results had aspiration. Pulmonary aspiration was demonstrated in all patients with apnea and 61.5% of patients with recurrent pneumonia. Nine of 25 patients (36%) with aspiration had histologic evidence of esophagitis, whereas histologic esophagitis was present in 5 of 13 patients (38.4%) with pathologic GER as shown by intraesophageal pH monitoring.

CONCLUSIONS

Pulmonary aspiration as demonstrated by overnight scintigraphy is common in children with unexplained and refractory respiratory manifestations, suggesting that GER could be the underlying cause of these manifestations. Since only a few children with chronic or recurrent respiratory symptoms have a pathologic gastroesophageal acid reflux, a normal intraesophageal pH study result does not rule out GER in these children.

Improved infant swallowing after gastroesophageal reflux disease treatment: a function of improved laryngeal sensation?

OBJECTIVE

The objective of this study was to describe improvements in pediatric swallowing after gastroesophageal reflux treatment.

STUDY DESIGN

The authors conducted a retrospective database and chart review at two tertiary care children's hospitals.

PARTICIPANTS

Patients (21 males, 7 females) ranged in age from 1 to 32 months. All patients had clinical evidence of gastroesophageal reflux disease (GERD) as well as evidence of dysphagia with aspiration (laryngeal vestibule and/or trachea) or hypopharyngeal pooling on flexible endoscopic evaluation of swallowing and sensation testing (FEESST) or videofluoroscopic swallow study (VSS).

INTERVENTION

Each child underwent either medical or surgical intervention for control of their GERD.

OUTCOME MEASURES

Outcome measures were change in laryngopharyngeal sensation and swallowing function with repeat swallow evaluation after GERD treatment.

RESULTS

A significant improvement in both swallow function and sensory testing was demonstrated after GERD treatment.

CONCLUSIONS

GERD may result in decreased laryngopharyngeal sensitivity, which may contribute to pediatric swallowing dysfunction. Control of GERD may improve swallow function. These findings have important clinical implications that need further study.

Identification and characterization of a specific sensory epithelium in the rat larynx

A specific laryngeal sensory epithelium (SLSE), which includes arrays of solitary chemoreceptor cells, is described in the supraglottic region of the rat. Two plates of SLSE were found, one on each side of the larynx. The first plate was located in the ventrolateral wall of the larynx, and the second was located in the interarytenoidal region. In SLSE, immunoblotting showed the presence of alpha-gustducin and phospholipase C beta2 (PLCbeta2), which are two markers of chemoreceptor cells. At immunocytochemistry, laryngeal immunoreactivity for alpha-gustducin was localized mainly in solitary chemosensory cells. Double-label immunocytochemistry using confocal microscopy demonstrated that alpha-gustducin-expressing cells in large part colocalize type III IP3 receptor (IP3R3), another key molecule in bitter taste perception. However, some IP3R3-expressing cells do not colocalize alpha-gustducin. At ultrastructural immunocytochemistry, these cells showed packed apical microvilli, clear cytoplasmic vesicles, and cytoneural junctions. SLSE was characterized by high permeability to a tracer due to poorly developed junctional contacts between superficial cells. Junctions were short in length and showed little contact with the terminal web. Ultrastructural analysis showed deep pits among the superficial cells. In SLSE, high density of intraepithelial nerve fibers was found. The lamina propria of the SLSE appeared thicker than that in other supraglottic regions. It was characterized by the presence of a well-developed subepithelial nerve plexus. The immunocytochemical and ultrastructural data suggested that SLSE is a chemoreceptor located in an optimal position for detecting substances entering the larynx from the pharynx or the trachea.

Relevance of the pH probe in sleep study analysis in infants

BACKGROUND

To establish the relationship between sleep apnoea and gastro-oesophageal reflux in infants and describe the clinical, demographic and pHmetric profile and the characteristic of the sleep polysomnography with a pH probe.

METHODS

A total of 102 consecutive patients were evaluated. Parents were requested to fill out a questionnaire about symptoms and previous therapy. Gastro-oesophageal reflux was considered abnormal when the percentage of time with pH less than 4 was higher than 4% of total sleep time.

RESULTS

A total of 102 infants were enrolled, 53% males. Seventy-four per cent of the infants were full-term babies. At the moment of the polysomnography, the mean age of the sample was 2.6 months. Suspicion of apnoea was the most common clinical diagnosis prior to the study. Only two infants have abnormal electroencephalogram. Mild gastro-oesophageal reflux was seen in 37 (36%) infants, while 22 (21.5%) did not have any reflux episode, and the remaining 43 (42%) infants had reflux index in the pathologic range. Only one patient had an unequivocal temporal relationship between acid oesophageal reflux and respiratory pause with oxygen desaturation.

DISCUSSION

Infants with history of apnoea or acute life threatening event frequently had gastro-oesophageal reflux episodes which did not correlated with respiratory events, suggesting that gastro-oesophageal reflux and apnoea often occur in the same infant as two separate events.

Alveolar Macrophage Apoptosis Contributes to Pneumococcal Clearance in a Resolving Model of Pulmonary Infection

The role of alveolar macrophages (AM) in host defense against pulmonary infection has been difficult to establish using in vivo models. This may reflect a reliance on models of fulminant infection. To establish a unique model of resolving infection, with which to address the function of AM, C57BL/6 mice received low-dose intratracheal administration of pneumococci. Administration of low doses of pneumococci produced a resolving model of pulmonary infection characterized by clearance of bacteria without features of pneumonia. AM depletion in this model significantly increased bacterial outgrowth in the lung. Interestingly, a significant increase in the number of apoptotic AM was noted with the low-dose infection as compared with mock infection. Caspase inhibition in this model decreased AM apoptosis and increased the number of bacteremic mice, indicating a novel role for caspase activation in pulmonary innate defense against pneumococci. These results suggest that AM play a key role in clearance of bacteria from the lung during subclinical infection and that induction of AM apoptosis contributes to the microbiologic host defense against pneumococci.

Evaluation of gastroesophageal reflux events in children using multichannel intraluminal electrical impedance

The majority of gastroesophageal reflux (GER) episodes in infants and children are nonacidic (pH >4). However, extraesophageal symptoms (e.g., breathing irregularities, apnea, aspiration) apparently can be caused by both acidic (pH <4) and nonacidic reflux. The standard diagnostic tool for suspected GER is pH monitoring. However, physicians should be aware of the limitations of pH monitoring in the pediatric population, because most reflux episodes in this age group are undetectable by this method. In contrast, the pH-independent multiple intraluminal electrical impedance technique (IMP) allows all bolus movements in the esophagus to be detected. Data can be analyzed for bolus composition and reflux height, duration, and clearance. Combining IMP with pH monitoring on a single catheter has proved to be a valuable tool for diagnosing GER and associated symptoms in infants and children.

The mismatch between evidence and practice. Common therapies in search of evidence

Many therapies in neonatology persist without supportive evidence: some common therapies may actually be harmful. Evidence-based medicine is the "conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients". The best available evidence, however, is not always sound or valid evidence. Sometimes, when faced with a collection of reports that do not constitute good evidence, attempts to choose the best evidence become pointless; in this case, a statement of no good evidence is preferable. There is a continuing problem with the place of usual practice in the hierarchy of evidence; usual practice generates experience with a particular practice but no reliable information regarding how the practice compares with alternative strategies. Although clinical and institutional inertia combined with a litigious practice environment tend to uphold current practice, the field of neonatology is ripe with examples of established therapies that were subsequently shown to be harmful. It is important to focus on important long-term outcomes and as much on the possibility of harm as on the chance of benefit, especially for new therapies, before they become routine practice. In the face of inadequate evidence, it is particularly important to avoid the temptation to institute treatment guidelines that inhibit further research. Patients are better served by guidelines that recommend only strategies that are supported by strong evidence and recommend further research when the evidence is inadequate.