Premium
Co‐ordination of spontaneous swallowing with respiratory airflow and diaphragmatic and abdominal muscle activity in healthy adult humans
Author(s) -
Hårdemark Cedborg Anna I.,
Sundman Eva,
Bodén Katarina,
Hedström Hanne Witt,
Kuylenstierna Richard,
Ekberg Olle,
Eriksson Lars I.
Publication year - 2009
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.2008.045724
Subject(s) - swallowing , medicine , expiration , anesthesia , ventilation (architecture) , respiratory system , diaphragmatic breathing , airway , normocapnia , exhalation , respiratory physiology , hypercapnia , spirometry , surgery , pathology , asthma , mechanical engineering , alternative medicine , engineering
Co‐ordination of breathing and swallowing is essential for normal pharyngeal function and to protect the airway. To allow for safe passage of a bolus through the pharynx, respiration is interrupted (swallowing apnoea); however, the control of airflow and diaphragmatic activity during swallowing and swallowing apnoea are not fully understood. Here, we validated a new airflow discriminator for detection of respiratory airflow and used it together with diaphragmatic and abdominal electromyography (EMG), spirometry and pharyngeal and oesophageal manometry. Co‐ordination of breathing and spontaneous swallowing was examined in six healthy volunteers at rest, during hypercapnia and when breathing at 30 breaths min –1 . The airflow discriminator proved highly reliable and enabled us to determine timing of respiratory airflow unambiguously in relation to pharyngeal and diaphragmatic activity. During swallowing apnoea, the passive expiration of the diaphragm was interrupted by static activity, i.e. an ‘active breath holding’, which preserved respiratory volume for expiration after swallowing. Abdominal EMG increased throughout pre‐ and post‐swallowing expiration, more so during hyper‐ than normocapnia, possibly to assist expiratory airflow. In these six volunteers, swallowing was always preceded by expiration, and 93 and 85% of swallows were also followed by expiration in normo‐ and hypercapnia, respectively, indicating that, in man, swallowing during the expiratory phase of breathing may be even more predominant than previously believed. This co‐ordinated pattern of breathing and swallowing potentially reduces the risk for aspiration. Insights from these measurements in healthy volunteers and the airflow discriminator will be used for future studies on airway protection and effects of disease, drugs and ageing.