Effet de la pression positive continue ou intermittente administrée par voie nasale sur les déglutitions non-nutritives chez l'agneau nouveau-né

Alors que les problèmes respiratoires et de déglutitions sont fréquemment rencontrés en période néonatale, l'interaction entre ces deux phénomènes demeure encore très peu documentée. Ceci est particulièrement vrai dans des conditions où un support ventilatoire nasal en pression positive continue (PPC) ou en pression positive intermittente (VPPI) est employé chez les nouveau-nés. Les résultats montrent que globalement, la PPC diminue significativement la fréquence des DNN, plus spécifiquement les DNN isolées en sommeil calme et les DNN en bouffées en sommeil agité. En comparaison, les effets de la VPPI sont plus variables, avec une diminution significative de la fréquence des DNN à l'éveil seulement, et une augmentation significative de la fréquence des DNN isolées en sommeil agité. Finalement, ni la PPC ni la VPPI n'altère la coordination entre les DNN et les phases du cycle respiratoire. La PPC 6 cm H[indice inférieur 2]O nasale inhibe les DNN chez l'agneau nouveau-né. La pertinence clinique de cette nouvelle découverte est reliée à l'importance des DNN en période néonatale pour la clairance des sécrétions et du contenu gastrique qui reflue fréquemment dans le pharynx. De plus, les modifications des DNN, par l'administration prolongée d'une PPC nasale en période néonatale, pourraient avoir un impact sur la maturation de la fonction de déglutition, dû à la plasticité du cerveau du nouveau-né."--Résumé abrégé par UMI

Multimodal analysis of synchronization data from patients with dementia

Little is known about the abilities of people with dementia to synchronize bodily movements to music. The lack of non-intrusive tools that do not hinder patients, and the absence of appropriate analysis methods may explain why such investigations remain challenging. This paper discusses the development of an analysis framework for processing sensorimotor synchronization data obtained from multiple measuring devices. The data was collected during an explorative study, carried out at the University Hospital of Reims (F), involving 16 individuals with dementia. The study aimed at testing new methods and measurement tools developed to investigate sensorimotor synchronization capacities in people with dementia. An analysis framework was established for the extraction of quantity of motion and synchronization parameters from the multimodal dataset composed of sensor, audio, and video data. A user-friendly monitoring tool and analysis framework has been established and tested that holds potential to respond to the needs of complex movement data handling. The study enabled improving of the hardware and software robustness. It provides a strong framework for future experiments involving people with dementia interacting with music

Interactions des déglutitions non-nutritives avec la respiration de la période néonatale jusqu'à l'âge adulte

Les problèmes respiratoires et de la déglutition constituent des problèmes fréquemment rencontrés en période néonatale et perturbent la qualité de vie de millions de patients adultes. Malgré ces constatations cliniques, l'interaction entre ces deux fonctions demeure encore peu connue et ceci est particulièrement vrai pour les déglutitions non-nutritives (DNN), qui assurent le rôle fondamental de clairance des sécrétions salivaires oro-pharyngées et gastro-pharyngées. En effet, les interactions entre DNN et respiration sont cruciales chez le nouveau-né afin d'empêcher les aspirations trachéales et la prolongation des apnées. Par conséquent, plusieurs facteurs, tels que la ventilation nasale, le développement pré- et postnatal ainsi que la posture, peuvent avoir un effet sur ces interactions et engendrer des conséquences désastreuses. Ainsi, les objectifs de ce doctorat étaient: (1) d'identifier le(s) mécanisme(s) réflexe(s) à l'origine de l'inhibition des DNN suite à l'application d'une pression positive continue (CPAP) par masque nasal durant le sommeil calme (SC) chez l'agneau nouveau-né, (2) de caractériser la coordination DNN - respiration chez l'ovin adulte, (3) de déterminer l'effet de la posture et du genre sur la coordination DNN - respiration chez l'adulte humain. Pour réaliser ces trois études, nous avons étudié (1) L'implication des récepteurs des voies aériennes supérieures et inférieures dans l'effet inhibiteur de la CPAP sur les DNN, grâce à deux modèles animaux distincts soit: 6 agneaux ayant subi une séparation chronique entre les voies aériennes supérieures (VAS) et inférieures (VAI) et 6 autres ayant subi une vagotomie bilatérale différée par vidéo-thoracoscopie; (2) La fréquence et la coordination des DNN avec la respiration en fonction des stades de conscience chez 6 brebis adultes; (3) La coordination DNN - respiration chez 12 participants (6 hommes et 6 femmes) adultes en fonction de trois postures expérimentales (assise vs. couchée vs. à 4 pattes) et interprétée par deux types d'analyse.Les résultats de ces trois études ont montré que: (1) L'effet inhibiteur de la CPAP sur les DNN durant le SC est médié par les récepteurs VAI dans toutes les conditions expérimentales, tandis que les récepteurs des VAS n'y sont impliqués que dans une seule; (2) La coordination DNN - respiration de la brebis adulte est similaire à celle des agneaux nouveau-nés prématurés et nés à terme avec une fréquence des DNN plus élevée en sommeil REM qu'à l'éveil et qu'en sommeil non-REM, et avec une prédominance des DNN survenant au cours de l'inspiration; (3)Les DNN surviennent plus précocement à l'intérieur du cycle respiratoire chez les hommes que chez les femmes et la posture n'a aucun effet sur la coordination DNN - respiration. En conclusion, les résultats de ces trois études ont mis en évidence que: (1) Aussi bien les récepteurs des VAI que des VAS participent à l'effet inhibiteur de la CPAP sur les DNN, avec un effet plus cohérent des récepteurs des VAI dans tous les modèles expérimentaux; (2) La coordination DNN - respiration ne subit aucune maturation au cours du développement postnatal chez l'ovin; (3) Seulement le genre et non la posture influence la coordination DNN - respiration chez l'adulte humain

Absence of effect of nasal continuous positive-airway pressure on the esophageal phase of nutritive swallowing in newborn lambs

Objectives: It is presently recommended that oral feeding be started in premature infants as soon as possible, often at an age at which nasal continuous positive airway pressure (nCPAP) is still required for ventilatory support. Our previous data showed that application of nCPAP up to 10 cmH2O in full-term lambs had no deleterious effect on cardiorespiratory safety, feeding efficiency, or on nutritive swallowing-breathing coordination. Besides fear of swallowing-breathing coordination disturbances, esophageal motility disruption by nCPAP could be a reason to delay oral feeding. To our knowledge, no study has focused on the effects of nCPAP on esophageal motility in the neonatal period. The aim of the present study was therefore to further assess the effects of nCPAP on oral feeding by assessing its effects on the esophageal phase of nutritive swallowing (nutritive esophagodeglutition). Methods: Six full-term lambs, ages 2 to 3 days, underwent esophageal multichannel intraluminal impedance-pH monitoring. Lambs were bottle-fed under 2 randomized conditions, namely spontaneous breathing and nCPAP 6 cmH(2)O. Results: Beyond confirmation of unaltered feeding efficiency, analysis of multiple variables measured by impedance monitoring revealed that nCPAP 6 does not alter nutritive esophagodeglutition in any way (nCPAP vs spontaneous breathing, P > 0.1 for all variables). Conclusions: offering further support to neonatologists pleading for initiation of oral feeding in infants still on nCPAP, the present results set the foundations for similar clinical studies in preterm human infants to confirm the absence of effects of nCPAP on nutritive swallowing

Mathematical modeling of respiratory system mechanics in the newborn lamb.

International audienceIn this paper, a mathematical model of the respiratory mechanics is used to reproduce experimental signal waveforms acquired from three newborn lambs. As the main challenge is to determine specific lamb parameters, a sensitivity analysis has been realized to find the most influent parameters, which are identified using an evolutionary algorithm. Results show a close match between experimental and simulated pressure and flow waveforms obtained during spontaneous ventilation and pleural pressure variations acquired during the application of positive pressure, since root mean square errors equal to 0.0119, 0.0052 and 0.0094. The identified parameters were discussed in light of previous knowledge of respiratory mechanics in the newborn

Effects of nasal continuous positive airway pressure on nutritive swallowing in lambs

Current knowledge suggests that, to be successful, oral feeding in preterm infants should be initiated as soon as possible, often at an age where immature respiration still requires ventilatory support in the form of nasal continuous positive airway pressure (nCPAP). While some neonatologist teams claim great success with initiation of oral feeding in immature infants with nCPAP, others strictly wait for this ventilatory support to be no longer necessary before any attempt at oral feeding, fearing laryngeal penetration and tracheal aspiration. Therefore, the aim of the present study was to provide a first assessment of the effect of various levels of nCPAP on bottle-feeding in a neonatal ovine model, including feeding safety, feeding efficiency, and nutritive swallowing-breathing coordination. Eight lambs born at term were surgically instrumented 48 h after birth to collect recordings of electrical activity of laryngeal constrictor muscle, electrocardiography, and arterial blood gases. Two days after surgery, lambs were bottle-fed under five randomized nCPAP conditions, including without any nCPAP or nasal mask and nCPAP of 0, 4, 7, and 10 cmH(2)O. Results revealed that application of nCPAP in the full-term lamb had no deleterious effect on feeding safety and efficiency or on nutritive swallowing-breathing coordination. The present study provides a first and unique insight on the effect of nCPAP on oral feeding, demonstrating its safety in newborn lambs born at term. These results open the way for further research in preterm lambs to better mimic the problems encountered in neonatology

Mechanisms of active laryngeal closure during non-invasive intermittent positive pressure ventilation in non-sedated lambs

The present study stems from our recent demonstration (Moreau-Bussiere F, Samson N, St-Hilaire M, Reix P, Lafond JR, Nsegbe E, Praud JP. J Appl Physiol 102: 2149-2157, 2007) that a progressive increase in nasal intermittent positive pressure ventilation (nIPPV) leads to active glottal closure in nonsedated, newborn lambs. The aim of the study was to determine whether the mechanisms involved in this glottal narrowing during nIPPV originate from upper airway receptors and/or from bronchopulmonary receptors. Two groups of newborn lambs were chronically instrumented for polysomnographic recording: the first group of five lambs underwent a two-step bilateral thoracic vagotomy using video-assisted thoracoscopic surgery (bilateral vagotomy group), while the second group, composed of six lambs, underwent chronic laryngotracheal separation (isolated upper airway group). A few days later, polysomnographic recordings were performed to assess glottal muscle electromyography during step increases in nIPPV (volume control mode). Results show that active glottal narrowing does not develop when nIPPV is applied on the upper airways only, and that this narrowing is prevented by bilateral vagotomy when nIPPV is applied on intact airways. In conclusion, active glottal narrowing in response to increasing nIPPV originates from bronchopulmonary receptors

Effects of reflux laryngitis on laryngeal chemoreflexes in newborn lambs

It has been suggested that reflux laryngitis (RL) is involved in apneas-bradycardias of the newborn. The aim of the present study was to develop a unique RL model in newborn lambs to test the hypothesis that RL enhances the cardiorespiratory components of the laryngeal chemoreflexes (LCR) in the neonatal period. Gastric juice surrogate (2 ml of normal saline solution with HCl pH 2 + pepsin 300 U/ml) (RL group, n = 6) or normal saline (control group, n = 6) was repeatedly injected onto the posterior aspect of the larynx, 3 times a day for 6 consecutive days, via a retrograde catheter introduced into the cervical esophagus. Lambs instilled with gastric juice surrogate presented clinical signs of RL, as well as moderate laryngitis on histological observation. Laryngeal chemoreflexes were thereafter induced during sleep by injection of 0.5 ml of HCl (pH 2), ewe's milk, distilled water or saline into the laryngeal vestibule via a chronic, transcutaneous supraglottal catheter. Overall, RL led to a significantly greater respiratory inhibition compared with the control group during LCR, including longer apnea duration (P = 0.01), lower minimal respiratory rate (P = 0.002), and a more prominent decrease in arterial hemoglobin saturation (SpO(2)) (P = 0.03). No effects were observed on cardiac variables. In conclusion, 1) our unique neonatal ovine model presents clinical and histological characteristics of RL; and 2) the presence of RL in newborn lambs increases the respiratory inhibition observed with LCR, at times leading to severe apneas and desaturations

An Automated Thematic Role Labeler and Generalizer for Filipino Verb Arguments

PACLIC 23 / City University of Hong Kong / 3-5 December 200

Origins of the inhibiting effects of nasal CPAP on non-nutritive swallowing in newborn lambs

The present study was aimed at investigating the principal reflex mechanism by which non-nutritive swallowing (NNS) is inhibited by application of a nasal CPAP 6 cm H2O during quiet sleep (QS) in newborn lambs. Eighteen full-term lambs were chronically instrumented and evenly distributed into 3 separate groups to sort out whether reflex activity originates from the upper or lower airway receptors. Six lambs were tracheotomized, six other lambs underwent a 2-step bilateral intrathoracic vagotomy while the remaining 6 lambs underwent chronic laryngo-tracheal separation (isolated upper airway group). Forty-eight hours after surgery, each nonsedated lamb underwent polysomnographic recordings on 3 consecutive days. States of alertness, NNS and respiratory movements were recorded. Results demonstrate that a CPAP of 6 cm H2O inhibited NNS during QS while administered directly on the lower airways. This NNS inhibition was prevented by eliminating the vagal afferent messages originating from the bronchopulmonary receptors. However, application of CPAP on the upper airways only also inhibited NNS during QS. Finally, the application of a CPAP 6 cm H2O had no systematic effect on NNS-breathing coordination. In conclusion, our results suggest that the inhibiting effect of nasal CPAP 6 cm H2O on NNS is mainly mediated by bronchopulmonary receptors with some participation however of upper airway receptors. Our demonstration that spontaneous, non-nutritive swallowing can be modulated by bronchopulmonary receptor activity further illustrates the physiological interactions between upper and lower airways