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The swallowing reflex and its significance as an airway defensive reflex.

Nishino T - Front Physiol (2013)

Bottom Line: Swallowing plays, not only an important role in food digestion, but also a major role in preventing the entrance of food and/or other materials into the lower respiratory tract.To achieve this, precise coordination is necessary between breathing and swallowing since the pharynx serves as a common pathway for both respiration and digestion.Among these, timing of swallows in relation to the phase of respiration may be the most important factor that determines the occurrence of pulmonary aspiration, since phases of inspiration and the expiration-inspiration transition are the most vulnerable for pulmonary aspiration.

View Article: PubMed Central - PubMed

Affiliation: Kaken Hospital Ichikawa, Japan.

ABSTRACT
Swallowing function, in humans, is very complex. Swallowing plays, not only an important role in food digestion, but also a major role in preventing the entrance of food and/or other materials into the lower respiratory tract. To achieve this, precise coordination is necessary between breathing and swallowing since the pharynx serves as a common pathway for both respiration and digestion. The swallowing reflex consists of afferent pathways, central integration, and efferent pathways. Any defect or disorder along reflex arc can cause a potential delay or impairment in swallow function. The swallowing reflex can be modulated not only by pathological factors but also by physiological factors. Among these, timing of swallows in relation to the phase of respiration may be the most important factor that determines the occurrence of pulmonary aspiration, since phases of inspiration and the expiration-inspiration transition are the most vulnerable for pulmonary aspiration.

No MeSH data available.


Related in: MedlinePlus

Different swallowing responses in different body positions. Respiratory and swallowing responses to continuous infusion of water into the pharynx were examined in an epiglottis-resected patient in both supine and sitting positions.
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Figure 1: Different swallowing responses in different body positions. Respiratory and swallowing responses to continuous infusion of water into the pharynx were examined in an epiglottis-resected patient in both supine and sitting positions.

Mentions: The epiglottis itself is not considered to be essential to effective swallowing function. In the absence of the epiglottis or normal epiglottic inversion, the hypolaryngeal complex is able to close the glottis and effectively protect the airway. Figure 1 shows different responses of swallowing to continuous infusion of water into the pharynx in a patient who underwent the resection of the epiglottis due to carcinoma of the epiglottis. We examined the effects of posture on swallowing response to continuous infusion of water in this patient. In a sitting position, a normal swallowing response to water instillation was observed in this patient. However, in a supine position this patient showed a vigorous coughing immediately after the start of water infusion, possibly indicative of discoordinated laryngeal closure and subsequent penetration or aspiration to the airway. Detailed analysis of the timing of swallows during continuous infusion of water shows that all the swallows in the sitting position took place at the expiration phase. On the other hand, in the supine position, the swallow coincided with inspiration initiated cough reflex. These findings suggest that in patients without the epiglottis, body position may affect the timing of swallows which plays an important role in protection of the airway from aspiration of swallowed material. Although human physiology may need gravity for pharyngeal movement of the bolus, it has been reported that in normal healthy subjects gravity does not influence pharyngeal bolus transport (Johnsson et al., 1995).


The swallowing reflex and its significance as an airway defensive reflex.

Nishino T - Front Physiol (2013)

Different swallowing responses in different body positions. Respiratory and swallowing responses to continuous infusion of water into the pharynx were examined in an epiglottis-resected patient in both supine and sitting positions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539657&req=5

Figure 1: Different swallowing responses in different body positions. Respiratory and swallowing responses to continuous infusion of water into the pharynx were examined in an epiglottis-resected patient in both supine and sitting positions.
Mentions: The epiglottis itself is not considered to be essential to effective swallowing function. In the absence of the epiglottis or normal epiglottic inversion, the hypolaryngeal complex is able to close the glottis and effectively protect the airway. Figure 1 shows different responses of swallowing to continuous infusion of water into the pharynx in a patient who underwent the resection of the epiglottis due to carcinoma of the epiglottis. We examined the effects of posture on swallowing response to continuous infusion of water in this patient. In a sitting position, a normal swallowing response to water instillation was observed in this patient. However, in a supine position this patient showed a vigorous coughing immediately after the start of water infusion, possibly indicative of discoordinated laryngeal closure and subsequent penetration or aspiration to the airway. Detailed analysis of the timing of swallows during continuous infusion of water shows that all the swallows in the sitting position took place at the expiration phase. On the other hand, in the supine position, the swallow coincided with inspiration initiated cough reflex. These findings suggest that in patients without the epiglottis, body position may affect the timing of swallows which plays an important role in protection of the airway from aspiration of swallowed material. Although human physiology may need gravity for pharyngeal movement of the bolus, it has been reported that in normal healthy subjects gravity does not influence pharyngeal bolus transport (Johnsson et al., 1995).

Bottom Line: Swallowing plays, not only an important role in food digestion, but also a major role in preventing the entrance of food and/or other materials into the lower respiratory tract.To achieve this, precise coordination is necessary between breathing and swallowing since the pharynx serves as a common pathway for both respiration and digestion.Among these, timing of swallows in relation to the phase of respiration may be the most important factor that determines the occurrence of pulmonary aspiration, since phases of inspiration and the expiration-inspiration transition are the most vulnerable for pulmonary aspiration.

View Article: PubMed Central - PubMed

Affiliation: Kaken Hospital Ichikawa, Japan.

ABSTRACT
Swallowing function, in humans, is very complex. Swallowing plays, not only an important role in food digestion, but also a major role in preventing the entrance of food and/or other materials into the lower respiratory tract. To achieve this, precise coordination is necessary between breathing and swallowing since the pharynx serves as a common pathway for both respiration and digestion. The swallowing reflex consists of afferent pathways, central integration, and efferent pathways. Any defect or disorder along reflex arc can cause a potential delay or impairment in swallow function. The swallowing reflex can be modulated not only by pathological factors but also by physiological factors. Among these, timing of swallows in relation to the phase of respiration may be the most important factor that determines the occurrence of pulmonary aspiration, since phases of inspiration and the expiration-inspiration transition are the most vulnerable for pulmonary aspiration.

No MeSH data available.


Related in: MedlinePlus