Citation

Pitts T, Rose MJ, Mortensen AN, Poliacek I, Sapienza CM, Lindsey BG, Morris KF, Davenport PW, Bolser DC. Respir. Physiol. Neurobiol. 2013; 189(3): 543-551.

Affiliation

Department of Physiological Sciences University of Florida Gainesville, FL. Electronic address: tepitts@ufl.edu.

Copyright

(Copyright © 2013, Elsevier Publishing)

DOI

10.1016/j.resp.2013.08.009

PMID

23998999

Abstract

Airway protection is the prevention and/or removal of material by behaviors, such as cough and swallow. We tested the hypothesis that cough and swallow, in response to aspiration, are a "meta-behavior" and thus are coordinated and have alterations in excitability to respond to aspiration risk and maintain homeostasis. Anesthetized animals were challenged with a protocol that simulated ongoing aspiration and induced both coughing and swallowing. Electromyograms of the mylohyoid, geniohyoid, thyrohyoid, thyroarytenoid, thyropharyngeus, cricopharyngeus, parasternal, rectus abdominis muscles together with esophageal pressure were recorded to identify and evaluate cough and swallow. During simulated aspiration, both cough and swallow intensity increased and swallow duration decreased consistent with a more rapid pharyngeal clearance. A phase restriction between cough and swallow was also observed; swallow was restricted to the E2 phase of cough during chest wall and abdominal motor quiescence. These results support the conclusion that the cough and swallow pattern generators are an airway protective meta-behavior. The resulting alterations in swallow drive during the simulated aspiration protocol also supports the conclusion that the trachea provides feedback on swallow quality, informing the brainstem about aspiration incidences. The overall coordination of cough and swallow led to the additional conclusion that mechanically the larynx and upper esophageal sphincter act as two separate valves controlling the direction of positive and negative pressures from the upper airway into the thorax.

Language: en