New insights into pharyngo-esophageal bolus transport revealed by pressure-impedance measurement

Author version made available in accordance with the publisher's policy.Introduction: Pharyngeal propulsion, strength of peristalsis and esophago-gastric junction (EJG) resistance are determinants of esophageal bolus transport. This study used pressure-impedance methods to correlate pharyngo-esophageal function with the esophageal bolus trajectory pathway and pressures generated during bolus transport. Methods: Pharyngo-esophageal pressure-impedance measurements were performed in 20 healthy adult controls. Pharyngeal automated impedance manometry was performed to derive pharyngeal swallow function variables. The esophageal time of nadir impedance (TZn) was used to track bolus trajectory pathway. The inflexion, or flow stasis point (FSP), of the trajectory curve was determined as were the pressures within the bolus (PZn) above and below the FSP. The size of 20mmHg isocontour defect measured the integrity of the peristaltic wave. Results: For viscous boluses, weaker pharyngeal bolus propulsion correlated with the FSP being located higher in the esophagus. Pressure within the bolus was observed to increase at the FSP and below the FSP in a manner that correlated with the magnitude of esophageal peak pressures. Larger 20mmHg isocontour defects were associated with lower pressures within the bolus at the FSP and below. Conclusion: The FSP of the bolus trajectory pathway appears to represent a switch from bolus propulsion due to pharyngeal mechanisms to bolus propulsion due to esophageal mechanisms. 20mmHg isocontour defects significantly reduce bolus driving pressure at or below the FSP

Supraesophageal Reflux Disease: Solving a Riddle Wrapped in a Mystery Inside an Enigma

Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0

Dysphagia in children with esophageal atresia: current diagnostic options

© 2017 Georg Thieme Verlag KGDysphagia or swallowing disorder is very common (range, 15–52%) in patients with esophageal atresia. Children present with a wide range of symptoms. The most common diagnostic tools to evaluate esophageal dysphagia, such as upper barium study and manometry, aim to characterize anatomy and function of the esophageal body and the esophagogastric junction (EGJ). Using these technologies, a variety of pathological motor patterns have been identified in children with esophageal atresia. However, the most challenging part of diagnosing patients with esophageal dysphagia lies in the fact that these methods fail to link functional symptoms such as dysphagia with the esophageal motor disorders observed. A recent method, called pressure-flow analysis (PFA), uses simultaneously acquired impedance and manometry measurements, and applies an integrated analysis of these recordings to derive quantitative pressure-flow metrics. These pressure-flow metrics allow detection of the interplay between bolus flow, motor patterns, and symptomatology by combining data on bolus transit and bolus flow resistance. Based on a dichotomous categorization, flow resistance at the EGJ and ineffective esophageal bolus transit can be determined. This method has the potential to guide therapeutic decisions for esophageal dysmotility in pediatric patients with esophageal atresia

Correlating stroke lesion location with clinical outcomes – an example from deglutition research

This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving'.Copyright © 2016 John Wiley & Sons, Inc. All rights reserved. This author accepted manuscript is made available following 12 month embargo from date of publication (23 April 2016) in accordance with the publisher's copyright policy

Oesophageal pressure-flow metrics in relation to bolus volume, bolus consistency and bolus perception

Author version made available in accordance with the publisher's policy.The utility of combined oesophageal pressure–impedance recording has been enhanced by automation of data analysis. To understand how oesophageal function as measured by automated impedance manometry (AIM) pressure-flow analysis varies with bolus characteristics and subjective perception of bolus passage. Oesophageal pressure–impedance recordings of 5 and 10 ml liquid or viscous swallows and 2 and 4 cm solid swallows from 20 healthy control subjects (five male; 25–73 years) were analysed. Metrics indicative of bolus pressurization (intrabolus pressure and intrabolus pressure slope) were derived. Bolus flow resistance, the relationship between bolus pressurization and flow timing, was assessed using a pressure-flow index. Bolus retention was assessed using the ratio of nadir impedance to peak pressure impedance (impedance ratio). Subjective perception of bolus passage was assessed swallow by swallow. Viscosity increased the bolus flow resistance and reduced bolus clearance. Responses to boluses of larger volume and more viscous consistency revealed a positive correlation between bolus pressurization and oesophageal peak pressure. Flow resistance was higher in subjects who perceived bolus hold up of solids. Bolus volume and bolus type alter oesophageal function and impact AIM analysis metrics descriptive of oesophageal function. Perception of bolus transit was associated with heightened bolus pressurization relative to bolus flow

Objective Prediction of Pharyngeal Swallow Dysfunction in Dysphagia through Artificial Neural Network Modelling

This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving'. © 2016 John Wiley & Sons LtdBackground Pharyngeal pressure-flow analysis (PFA) of high resolution impedance-manometry (HRIM) with calculation of the swallow risk index (SRI) can quantify swallow dysfunction predisposing to aspiration. We explored the potential use of artificial neural networks (ANN) to model the relationship between PFA swallow metrics and aspiration and to predict swallow dysfunction. Methods Two hundred consecutive dysphagia patients referred for videofluoroscopy and HRIM were assessed. Presence of aspiration was scored and PFA software derived 13 metrics and the SRI. An ANN was created and optimized over training cycles to achieve optimal classification accuracy for matching inputs (PFA metrics) to output (presence of aspiration on videofluoroscopy). Application of the ANN returned a value between 0.00 and 1.00 reflecting the degree of swallow dysfunction. Key Results Twenty one patients were excluded due to insufficient number of swallows (<4). Of 179, 58 aspirated and 27 had aspiration pneumonia history. The SRI was higher in aspirators (aspiration 24 [9, 41] vs no aspiration 7 [2, 18], p < 0.001) and patients with pneumonia (pneumonia 27 [5, 42] vs no pneumonia 8 [3, 24], p < 0.05). The ANN Predicted Risk was higher in aspirators (aspiration 0.57 [0.38, 0.82] vs no aspiration 0.13 [0.4, 0.25], p < 0.001) and in patients with pneumonia (pneumonia 0.46 [0.18, 0.60] vs no pneumonia 0.18 [0.6, 0.49], p < 0.01). Prognostic value of the ANN was superior to the SRI. Conclusions & Inferences In a heterogeneous cohort of dysphagia patients, PFA with ANN modeling offers enhanced detection of clinically significant swallowing dysfunction, probably more accurately reflecting the complex interplay of swallow characteristics that causes aspiration

Rheological Characterization of Clay-PolyesterComposites

AbstractPolymer-clay composites, which consist of clay particles dispersed in a polymeric matrix, have been used in different applications. Clay fillers are widely used in polymers as ways to produce cost-effective, strong, and energy efficient materials. The compounding and inclusion of particulate fillers in the polymers to get a homogenous material is a rather complex process. The processing of these materials, like mixing and moulding is strongly dependent on the particle-particle and particle-polymer interactions. Therefore, the fundamental understanding of the rheological properties of the polymer-clay composites is very important in the design of their processing. In this study, the rheological behaviour of bentonite clay dispersed in unsaturated polyester was investigated. Herschel-Bulkley model and Structural Kinetic model were used to describe the dependence of the apparent viscosity of the composite on shear rate and shearing time, respectively. The effects of the filler/polyester ratio and filler size on the rheological properties of the composite were studied

New insights in gastroesophageal reflux, esophageal function and gastric emptying in relation to dysphagia before and after anti-reflux surgery in children.

This item is under embargo for a period of 12 months from the date of publication, in accordance with the publisher's policy.In children with gastroesophageal reflux (GER) disease refractory to pharmacological therapies, anti-reflux surgery (fundoplication) may be a treatment of last resort. The applicability of fundoplication has been hampered by the inability to predict which patient may benefit from surgery and which patient is likely to develop post-operative dysphagia. pH impedance measurement and conventional manometry are unable to predict dysphagia, while the role of gastric emptying remains poorly understood. Recent data suggest that the selection of patients who will benefit from surgery might be enhanced by automated impedance manometry pressure-flow analysis (AIM) analysis, which relates bolus movement and pressure generation within the esophageal lumen

Effects of remifentanil on pharyngeal swallowing : A double blind randomized cross- over study in healthy volunteers

Copyright © European Society of Anaesthesiology. This author accepted manuscript is made available following 12 month embargo from date of publication (Sept 2016) in accordance with the publisher's copyright policy.BACKGROUND: Exposure to remifentanil increases the incidence of pulmonary aspiration in healthy volunteers. This effect may be explained by impairment of airway defence mechanisms and/or altered swallowing function. Pressure-flow analysis is a technique that allows objective assessment of swallowing based on pressure-impedance patterns recorded during bolus swallowing. OBJECTIVES: The aim of this study was to use pressure-flow analysis to quantify the effect of remifentanil on healthy pharyngeal swallowing and to compare these effects with morphine. DESIGN: A double-blind, randomised, cross-over study. SETTING: A tertiary care teaching hospital. VOLUNTEERS: Eleven young volunteers (mean age, 23 years) and seven older volunteers (mean age, 73 years). INTERVENTIONS: Volunteers were studied twice and received either a target-controlled remifentanil infusion (target concentrations: young, 3 ng ml-1; old, 2 ng ml-1) or a bolus injection of morphine (dose: young, 0.1 mg kg-1; old, 0.07 mg kg-1). Pharyngeal pressure and impedance were recorded with an indwelling catheter while swallowing 10 boluses of liquid during each measuring phase. Variables defining swallowing function were calculated and compared to determine drug effects. MAIN OUTCOME MEASURES: Pharyngeal pressure-flow variables following remifentanil exposure. RESULTS: Changes produced by remifentanil in the measured variables were consistent with greater dysfunction of swallowing. Both the strength of the pharyngeal contractions and pharyngeal bolus propulsion were reduced, whereas flow resistance was increased. The swallow risk index, a global index of swallowing dysfunction, increased overall. At the experimental doses tested, morphine produced similar, but less extensive effects on swallowing. CONCLUSION: Remifentanil induced dysfunction of the pharyngeal swallowing mechanism. This may contribute to an increased risk of aspiration

Characterization of esophageal motility and esophagogastric junction in preterm infants with bronchopulmonary dysplasia

Background: To characterize esophageal motility and function of the esophagogastric junction (EGJ) in preterm infants with bronchopulmonary dysplasia (BPD). Methods: High-resolution manometry with impedance was used to investigate esophageal motility and EGJ function in 28 tube-fed preterm infants with BPD. Patients with BPD were studied at term age during oral feeding. Thirteen healthy term-aged infants were included as controls. Esophageal analysis derived objective measures to evaluate esophageal contractile vigor, bolus distension pressure, EGJ relaxation, and EGJ barrier function (in rest and during respiration). In addition, we investigated the effect of BPD severity on these measures. Key results: A total of 140 nutritive swallows were analyzed (BPD, n = 92; controls, n = 48). Normal esophageal peristaltic wave patterns were observed in all infants. BPD patients had higher distal contractile esophageal strength compared with controls (Kruskal-Wallis (KW) P =.048), and their deglutitive EGJ relaxation was comparable to controls. Severe BPD patients showed higher bolus distension pressures, higher EGJ resting pressures, and increased EGJ contractile integrals compared with mild BPD patients (Mann-Whitney U P =.009, KW P =.012 and KW P =.028, respectively). Conclusions and Inferences: Preterm infants with BPD consistently present with normal peristaltic esophageal patterns following nutritive liquid swallows. The EGJ barrier tone and relaxation pressure appeared normal. In general, infants with BPD do not have altered esophageal motor function. There is however evidence for increased flow resistance at the EGJ in severe BPD patients possibly related to an increased contractility of the diaphragm