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Effects of Tracheal Distension on Upper Airway Reflex Responsiveness in Cat
Author(s) -
Shen Tabitha,
Musselwhite M,
Rose Melanie,
Bolser Donald,
Pitts Teresa
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1012.8
Subject(s) - medicine , distension , cuff , airway , anesthesia , reflex , cough reflex , balloon , anatomy , surgery
A tracheostomy cuff is used in patients to ensure no material enters the lower airway. To clinically determine whether a patient is ready for cuff‐deflation airway protective reflexes are tested, often while the cuff is actively distending the trachea. We hypothesized that tracheal distension alters normal sensory feedback and decreases airway protective reflex efficacy. In adult cats, a balloon was inflated at the 4th cartilaginous ring of the trachea, and electromyography (EMG) activities from the diaphragm, internal oblique, crycoarytenoid and mylohyoid muscles were recorded. Cough was stimulated by mechanical stimulation of the intrathoracic trachea. Swallow was elicited by a water bolus to the oropharynx. The presence of the deflated balloon in the trachea greatly promoted the number of swallows (105±60%). Moderate tracheal distention decreased diaphragm (~20%) and internal oblique (~30%) EMG activity compared to baseline during cough, and partially recovered 10 minutes after distension was removed. Cough number decreased by 52±13% during tracheal distension. No significant effect on crycoarytenoid or mylohyoid (~4%) EMG activity during swallow was observed. However, large tracheal distensions induced depression in swallow EMG magnitude and number. These results indicate that tracheal distension in the physiological range alters sensory feedback that is important in the production of cough but not swallow, although the production of swallow can be negatively affected by distensions that increase the risk of mechanical or ischemic damage to tracheal tissue. Therefore, clinical assessments of cough when a tracheal cuff is or recently has been present may not represent a metric of normal function. Supported by HL 103425.