The Impact of Palatal Local Anesthesia on Pharyngeal Swallowing

Objectives: Oral sensation plays a vital role in the development of the cyclic behavior of feeding, however, the impact of the absence of such sensation on suckling and swallowing is unknown. Our objective was to test the hypothesis that the absence of perioral sensation affects the frequency and duration of suckling and swallowing in an infant pig model.

Methods: Each of three animals received three treatments, randomly administered on three separate days. The treatments were local infiltrations to the lips, of (1) saline and (2) bupivacaine, a long-lasting local anesthetic and (3) control. Feeding function was measured from videofluoroscopy (30 fps) at three time points daily. Sequential frames from the videos were digitized to extract the dependent variables of (1) swallow duration, (2) suck cycle duration, (3) suck-swallow cycle duration and (4) sucks per swallow for both control and treatment feedings. We tested our hypothesis using an analysis of variance (ANOVA) and Tukey’s test.   

Results: Swallow cycle duration was significantly longer for animals with the local anesthesia treatment as compared to the saline treatment (p=0.03). There was no effect of time of day within a treatment. The ratio of sucks per swallow differed among the three groups, with the highest for pigs with local anesthesia, and the lowest in the control animals (p<0.001).

Conclusions:  These findings indicate that perioral sensation impacts pharyngeal function by extending the duration of swallowing cycles. The results also indicate that the frequency of suckling and swallowing cycles is altered when perioral sensation is removed. These findings indicate that perioral sensation is important in regulating the frequency of swallowing and suckling cycles and the duration of the pharyngeal phase of the swallow.