Non-nutritive Swallowing Research Articles

Effects of reflux laryngitis on non-nutritive swallowing in newborn lambs

Reflux laryngitis in infants may be involved not only in laryngeal disorders, but also in disorders of cardiorespiratory control through its impact on laryngeal function. Our objective was to study the effect of reflux laryngitis on non-nutritive swallowing (NNS) and NNS-breathing coordination. Two groups of six newborn lambs, randomized into laryngitis and control groups, were surgically instrumented for recording states of alertness, swallowing and cardiorespiratory variables without sedation. A mild to moderate reflux laryngitis was induced in lambs from the experimental group. A significant decrease in the number of NNS bursts and apneas was observed in the laryngitis group in active sleep (p=0.03). In addition, lower heart and respiratory rates, as well as prolonged apnea duration (p<0.0001) were observed. No physiologically significant alterations in NNS-breathing coordination were observed in the laryngitis group. We conclude that a mild to moderate reflux laryngitis alters NNS burst frequency and autonomous control of cardiac activity and respiration in lambs.

133 Physiology of the Airway and its Control

Nature, Key Functions, Neural Control & Clinical Impact.The airway is a dynamic conduit, extending from the nose to the air sacs. Its key functions include protection, volume maintenance and ventilation,...

Effects of postnatal environmental tobacco smoke on non-nutritive swallowing-breathing coordination in newborn lambs

While prenatal environmental tobacco smoke (ETS) exposure is a well-known risk factor for sudden infant death syndrome, the effect of postnatal ETS exposure is less clear. The objective of this study was to investigate the effect of postnatal ETS exposure on non-nutritive swallowing (NNS) and NNS-breathing coordination, which are crucial to prevent aspiration related-cardiorespiratory events. Eighteen newborn lambs (6 per group) were randomly exposed to either 10 cigarettes/day, 20 cigarettes/day or room air for 15 days. Lambs were instrumented for recording states of alertness, swallowing, electrocardiogram and breathing; recordings were performed in non-sedated lambs at the end of ETS exposure. Urinary cotinine/creatinine ratio confirmed relevant real-life exposure. Postnatal ETS exposure had no effect on NNS frequency but tended to decrease inspiratory NNS (p=0.07) during quiet sleep. No effect on respiratory or heart rate (p>0.6), apnea index (p=0.2) or sleep states (p=0.3) was observed. In conclusion, postnatal ETS exposure in lambs had only mild effects on NNS-breathing coordination.

The mandible advancement may alter the coordination between breathing and the non-nutritive swallowing reflex

The coordination between nasal breathing and non-nutritive swallowing serves as a protective reflex against potentially asphyxiating material, i.e. saliva and secretions, entering the respiratory tract. Although this protective reflex is influenced by positional changes in the head and body, the effect of mandible position on this reflex is not fully understood. We examined the effect of mandible advancement associated with mouth opening on the coordination between nasal breathing and non-nutritive swallowing induced by continuous infusion of distilled water into the pharyngeal cavity. The combination of mandible advancement and mouth opening increased the duration of swallowing apnoea and submental electromyographic burst duration. When the mandible was advanced with the mouth open, the duration of swallowing apnoea increased significantly compared with the centric position (0.79 +/- 0.23 vs. 0.64 +/- 0.12 s, P < 0.05, n = 12), and the duration of submental electromyographic activity increased significantly (2.11 +/- 0.63 vs. 1.46 +/- 0.25 s, P < 0.05, n = 12). Mandible advancement with mouth opening altered the respiratory phase resetting during swallowing and the timing of swallow in relation to respiratory cycle phase. We conclude that mandible re-positioning may strongly influence the coordination between nasal breathing and non-nutritive swallowing by altering respiratory parameters and by inhibiting movement of the tongue-jaw complex.

Origins of the inhibiting effects of nasal CPAP on nonnutritive swallowing in newborn lambs

The present study investigated the mechanism by which continuous positive airway pressure (CPAP) suppresses nonnutritive swallowing (NNS) during quiet sleep (QS) in newborn lambs. Eighteen full-term lambs were chronically instrumented and evenly distributed into three separate groups to determine the extent to which modulation of NNS may be attributed to stimulation of upper airway and/or bronchopulmonary mechanoreceptors. Six lambs were tracheotomized, six other lambs underwent a two-step bilateral intrathoracic vagotomy, and the remaining six lambs underwent chronic laryngotracheal separation (isolated upper airway group). Forty-eight hours after surgery, each nonsedated lamb underwent polysomnographic recordings on three consecutive days. States of alertness, NNS and respiratory movements were recorded. Results demonstrate that a CPAP of 6 cmH(2)O inhibited NNS during QS while administered directly on the lower airways and that bivagotomy prevented this inhibition. However, application of CPAP on the upper airways only also inhibited NNS during QS. Finally, the application of a CPAP of 6 cmH(2)O had no systematic effect on NNS-breathing coordination (assessed by the respiratory phase preceding and following NNS). In conclusion, our results suggest that bronchopulmonary receptors are implicated in the inhibiting effects of nasal CPAP of 6 cmH(2)O on NNS in all our experimental conditions, whereas upper airway receptors are only implicated in certain conditions.

Respiratory-swallowing interactions during sleep in premature infants at term

Non-nutritive swallowing occurs frequently during sleep in infants and is vital for fluid clearance and airway protection. Swallowing has also been shown to be associated with prolonged apnea in some clinical populations. What is not known is whether swallowing contributes to apnea or may instead help resolve these clinically significant events. We studied the temporal relationships between swallowing, respiratory pauses and arousal in six preterm infants at term using multi-channel polysomnography and a pharyngeal pressure transducer. Results revealed that swallows occurred more frequently during respiratory pauses and arousal than during control periods. They did not trigger the respiratory pause, however, as most swallows (66%) occurred after respiratory pause onset and were often tightly linked to arousal from sleep. Swallows not associated with respiratory pauses (other than the respiratory inhibition to accommodate swallowing) and arousal occurred consistently during the expiratory phase of the breathing cycle. Results suggest that swallowing and associated arousal serve an airway protective role during sleep and medically stable preterm infants exhibit the mature pattern of respiratory-swallowing coordination by the time they reach term.

Effects of hypoxia and hypercapnia on nonnutritive swallowing in newborn lambs

The aim of the present study was to investigate the effect of hypercapnia and hypoxia on apnea and nonnutritive swallowing (NNS) frequency, as well as on the coordination between NNS and phases of the respiratory cycle in newborn lambs, while taking into account the potential effects of states of alertness. Six lambs were chronically instrumented for recording electroencephalogram, eye movements, diaphragm and thyroarytenoid muscle (a glottal adductor) activity, nasal airflow, and electrocardiogram. Polysomnographic recordings were performed in nonsedated lambs exposed to air (control), 10% O(2), and 5% CO(2) in a random order at 3, 4, and 5 days of age. Although hypercapnia decreased apnea frequency in wakefulness and active sleep (P = 0.002 vs. air and hypoxia), hypoxia had no significant effect on apnea. In addition, although hypercapnia increased NNS frequency during wakefulness and quiet sleep (P < 0.005 vs. air and hypoxia), hypoxia tended to decrease NNS frequency. Finally, only hypercapnia altered NNS-breathing coordination by increasing NNS at the transition from inspiration to expiration (ie-type NNS; P < 0.001 vs. air and hypoxia). In conclusion, whereas hypercapnia increases overall NNS frequency by specifically increasing ie-type NNS, hypoxia has the inverse tendency. Results were identical in all three states of alertness.

Non-Nutritive Swallowing and Respiration Coordination among States of Alertness in Adult Sheep

Swallowing is a powerful inhibitor of respiration. Its coordination with respiration is therefore crucial to avoid aspiration and apnea. The aim of this study was to determine the coordination between non-nutritive swallowing (NNS) and phases of the respiratory cycle, including the assessment of the effect of states of alertness in adult sheep. Six animals were surgically instrumented under general anesthesia to record electroencephalography, electro-oculography (state of alertness), diaphragmatic electromyography (EMG), nasal flow (respiration), esophageal EMG, and the thyroarytenoid muscle (NNS). Our results revealed that (1) the highest NNS frequency is observed in rapid eye movement (REM) sleep, especially for bursts of NNS; (2) while NNS begins mainly during inspiration in all states of alertness, REM sleep, however, is responsible for an increase in the proportion of NNS beginning in expiration; (3) the link between inspiration and NNS is not affected by rumination. In conclusion, the link between NNS and inspiration in adult sheep is similar to that of lambs but contrary to previous reports on NNS induced by water in humans. Whether these differences are related to interspecies differences or the experimental techniques clearly needs further studies on spontaneous NNS in humans.

Nutritive and non-nutritive swallowing apnea duration in term infants: Implications for neural control mechanisms

The impact of bolus ingestion and level of consciousness on swallowing apnea duration (SAD) in healthy term infants has not been adequately explored despite the likely contribution of swallowing apnea to upper airway protection against aspiration. SAD during wakefulness, sleep, and feeding (breast or bottle) of 10 term infants was measured 10 times from birth to 1 year of age. Nineteen thousand four hundred and two swallows were analyzed. Irrespective of age, SAD during feeding was significantly shorter than SAD of non-nutritive swallowing (during wakefulness and sleep). SAD did not change significantly within the first year of life in any of the three conditions and there was no change in the relative durations of nutritive, wake and sleep conditions with age. The absence of an age effect implies that the neural mechanisms controlling SAD are fundamentally brainstem-mediated and largely hard-wired at birth in healthy term neonates.

D2/195 – Effects of hypercapnia on non-nutritive swallowing

D2/195 – Effects of hypercapnia on non-nutritive swallowing

Laryngeal function and nasal ventilatory support in the neonatal period

Nasal application of positive airway pressure, either intermittently or continuously, is increasingly used in the neonatal period. An important difference however when using a nasal interface as opposed to an endotracheal tube for ventilatory support is the interposition of the larynx. Recent animal studies from our laboratory showed that nasal ventilatory support in the neonatal period can significantly impact laryngeal function. This includes active laryngeal closure against intermittent positive pressure ventilation, which can limit lung ventilation, and inhibition of non-nutritive swallowing, which may delay swallowing maturation. Those novel findings are highly relevant to neonatal respiratory care. Additional studies are underway to uncover both the mechanisms involved and consequences on lung ventilation and swallowing function.

Can we breathe and swallow at the same time?

The article by Samson et al. ([7][1]) in this issue of the Journal of Applied Physiology raises new issues concerning the regulation of nonnutritive swallowing (NNS) and breathing during sleep. The past 10 years have seen a large increase in interest in this field ([2][2], [3][3]). Clearly, NNS is

C-FIBER BLOCKADE INFLUENCE NON-NUTRITIVE SWALLOWING IN NEWBORN LAMBS

PURPOSE: Non-nutritive swallowing (NNS) is especially important in the neonatal period for clearing secretions and gastro-pharyngeal reflux, and has been associated with neonatal apneas. One previous study has reported that systemic C-fiber blockade (CFB) inhibits induced swallowing in adult guinea pigs (Jin, Y et al, Am J Respir Crit Care Med. 1994). The aim of our present study was to investigate the effects of CFB on apnea and NNS frequency, and on the coordination between NNS and phases of the respiratory cycle in newborn lambs.

C-fiber blockade influence on non-nutritive swallowing in full-term lambs

Systemic C-fiber blockade (CFB) has been reported to inhibit induced swallowing in adult guinea pigs. The aim of this study was to investigate the effects of CFB on spontaneous, non-nutritive swallowing (NNS) frequency and NNS-respiration coordination in the neonatal period. Seven CFB lambs and seven control lambs aged 2+/-1 days were chronically instrumented for recording electroencephalogram, eye movements, diaphragm EMG, thyroarytenoid muscle EMG, nasal airflow and electrocardiogram. Polysomnographic recordings were performed in non-sedated lambs, using radiotelemetry transmission. CFB lambs spent more time in active sleep than controls (p=0.02). Frequency of non-nutritive swallowing was not different in CFB and control lambs, whatever the state of alertness. In addition, CFB did not disrupt the overall respiratory-swallowing coordination, inspiratory-related NNS being the most frequent and expiratory-related NNS the least in both CFB and control lambs. Further analyses revealed that CFB had no effect on baseline respiratory and heart rate, and apnea and sigh frequency, whatever the state of alertness. Our results suggest that, in the neonatal period, C-fibers are not involved in NNS frequency and have no influence on the overall respiratory-swallowing coordination.

Effect of nasal continuous or intermittent positive airway pressure on nonnutritive swallowing in the newborn lamb

The present study was aimed at investigating the effects of nasal continuous positive airway pressure (nCPAP; 6 cmH2O) or intermittent positive pressure ventilation (nIPPV; 10/4 cmH2O) on nonnutritive swallowing (NNS) and on the coordination between NNS and phases of the respiratory cycle, while taking into account the potential effects of states of alertness. Twelve full-term lambs were chronically instrumented at 48 h after birth for polysomnographic recordings, including NNS, diaphragm electromyographic activity, respiratory movements, pulse oximetry, and states of alertness. Studies in control conditions, with nCPAP and nIPPV, were performed in random order in nonsedated lambs at 4, 5, and 6 days of life. Results demonstrate that nCPAP significantly decreased overall NNS frequency, more specifically isolated NNS during quiet sleep and bursts of NNS in active sleep. In comparison, the effects of nIPPV on NNS frequency were more variable, with an inhibition of NNS only in wakefulness and an increase in isolated NNS frequency in active sleep. In addition, neither nCPAP nor nIPPV disrupted the coordination between NNS and phases of the respiratory cycle. In conclusion, nCPAP inhibits NNS occurrence in newborn lambs. Clinical relevance of this novel finding is related to the importance of NNS for clearing the upper airways from secretions and gastric content frequently regurgitated in the neonatal period.

Upper airways and neonatal respiration

The upper airways exert an important influence on breathing from the fetal period onward. This review focuses on recent results obtained in the newborn, particularly on laryngeal function in the lamb. Cumulated data can be summarized as follows. Firstly, upper airway closure, either at the pharyngeal or laryngeal level, is now known to occur during central apneas. By maintaining a high apneic lung volume throughout central apneas, active laryngeal closure decreases the magnitude of post-apneic desaturation. Secondly, reflexes originating from laryngeal mucosal receptors, such as laryngeal chemoreflexes and non-nutritive swallowing, are of crucial importance within the context of preterm birth, postnatal maturation, neonatal apneas and apparent life-threatening events/sudden infant death syndrome. While laryngeal chemoreflexes appear to be mature and confer an efficient protection against aspiration in the full-term healthy newborn, they can be responsible for prolonged apneas and bradycardias in the immature preterm newborn. In regard to non-nutritive swallowing, the absence of swallowing activity during apneas in periodic breathing during quiet sleep as well as the presence of bursts of swallows with apneas in active sleep remain to be explained. Forthcoming studies will have to further delineate the impact of common clinical conditions, such as cigarette smoke exposure and/or viral respiratory infection on laryngeal chemoreflexes and non-nutritive swallowing. Better knowledge on the importance of the upper airways in neonatal respiration will ultimately aid in designing clinical applications for the understanding and treatment of severe, pathological respiratory conditions of the newborn.

Nonnutritive swallowing and respiration relationships in preterm lambs.

The aim of the present study was to assess the effects of the different states of alertness on 1) nonnutritive swallowing (NNS) frequency, 2) the relationship between NNS and the respiratory cycle, and 3) the association of NNS with spontaneous apneas. Recordings of sleep states, diaphragm and laryngeal constrictor electrical activity, nasal flow, electrocardiogram, respiratory inductance plethysmography, and pulse oximetry were obtained from six preterm lambs without sedation. Analysis of 2,468 NNS showed that 1) NNS frequency was higher during quiet wakefulness and active sleep (AS) than in quiet sleep; 2) in all states of alertness, a greater number of NNS (38%) were preceded and followed by an inspiration; 3) although NNS and central apneas were rarely coincidental, AS appeared to favor their association; and 4) most obstructive apneas occurred in AS and were coincidental with bursts of NNS. Compared with results in full-term lambs, premature birth does not modify the NNS-respiratory coordination. However, AS in preterm lambs is characterized by a higher association of NNS bursts with obstructive apneas.

Influence of stimulus pattern on reflex deglutition.

ArticleInfluence of Stimulus Pattern on Reflex DeglutitionRobert W. DotyRobert W. DotyFrom the Department of Physiology, University of Chicago, Chicago, IllinoisPublished Online:01 Jul 1951https://doi.org/10.1152/ajplegacy.1951.166.1.142MoreSectionsPDF (3 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByCentral Respiration and Mechanical Ventilation in the Gating of Swallow With Breathing25 June 2018 | Frontiers in Physiology, Vol. 9Vibration over the larynx increases swallowing and cortical activation for swallowingRachel W. Mulheren and Christy L. Ludlow5 September 2017 | Journal of Neurophysiology, Vol. 118, No. 3Using devices to upregulate nonnutritive swallowing in typically developing infantsSarah Hegyi Szynkiewicz, Rachel W. Mulheren, Kathryn W. Palmore, Cynthia R. O'Donoghue, and Christy L. Ludlow1 October 2016 | Journal of Applied Physiology, Vol. 121, No. 4Nitric oxide modulates elicitation of reflex swallowing from the pharynx in ratsHiroshi Kijima, Tomio Shingai, Yoshihiro Takahashi, Yuka Kajii, Shin-ichi Fukushima, Yo Taguchi, Tadashi Noda, and Yoshiaki Yamada1 September 2006 | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Vol. 291, No. 3Pharyngeal branch of the glossopharyngeal nerve plays a major role in reflex swallowing from the pharynxJun-Ichi Kitagawa, Tomio Shingai, Yoshihiro Takahashi, and Yoshiaki Yamada1 May 2002 | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Vol. 282, No. 5Suppression of vagal motor activities evokes laryngeal afferent-mediated inhibition of gastric motilityMotoi Kobashi, Tomoshige Koga, Masatoshi Mizutani, and Ryuji Matsuo1 March 2002 | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Vol. 282, No. 3Brain Stem Control of Swallowing: Neuronal Network and Cellular MechanismsAndré Jean1 April 2001 | Physiological Reviews, Vol. 81, No. 2Characterization and mechanisms of the pharyngoesophageal inhibitory reflexIvan M. Lang, Bidyut K. Medda, Junlong Ren, and Reza Shaker1 November 1998 | American Journal of Physiology-Gastrointestinal and Liver Physiology, Vol. 275, No. 5 More from this issue > Volume 166Issue 1July 1951Pages 142-158 Copyright & PermissionsCopyright © 1951 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1951.166.1.142PubMed14857157History Received 18 December 1950 Published online 1 July 1951 Published in print 1 July 1951 Metrics