Swallowing Kinematics and Airway Protection After Palatal Local Anesthesia in Infant Pigs

Objectives/HypothesisAbnormal kinematics during swallowing can result in aspiration, which may become life threatening. We tested the role of palatal sensation in the motor control of pharyngeal swallow in infants. Study DesignIn eight infant pigs, we reduced palatal sensation using local anesthesia (PLA) and measured the impact on swallowing kinematics and airway protection. MethodsThe pigs drank milk containing barium while we simultaneously recorded videofluoroscopy and electromyography from fine wire bipolar electrodes in several hyolaryngeal muscles. We compared these results to control feedings and feedings following palatal saline injections. ResultsAfter PLA, four pigs had extreme jaw movements and abnormal tongue movement uncharacteristic of sucking. For this reason, we evaluated differences between these group B pigs and the others that could suck normally after PLA (group A). In the four group A pigs, after PLA there was less hyoid elevation (P<.001) but normal jaw and tongue movements. In group B, in addition to greater jaw movement (P<.001) there was more anterior and superior tongue movement (P<.001) and a larger range of hyoid movement (P<.001). ConclusionsThe airway was protected in all of the pigs, indicating that these changes allowed successful adaptation to the reduction in palatal sensation. However, the oral and pharyngeal phases of the swallow were functionally linked, and trigeminal sensation influenced the motor control of the pharyngeal swallow. Level of EvidenceN/A Laryngoscope, 124:436-445, 2014