Pharyngeal Pressure and Timing During Bolus Transit

Abstract

Determining intrabolus pressure (IBP) at the upper esophageal sphincter (UES) and in the esophagus has given compelling evidence that IBP can be a predictor for swallowing dysfunction. Studies have looked most superiorly at the low hypopharynx region but there has been no inquiry into what IBP measures throughout the entire pharynx can tell us. We present a study to describe the pressures within and surrounding the moving bolus throughout the pharynx and into the UES. Simultaneous HRM and videofluoroscopy were performed in 10 healthy subjects swallowing ten 10 mL thin-liquid barium boluses. Three events surrounding bolus movement were tracked via videofluoroscopy, two additional events were found using manometric measures. As the bolus passes through the pharynx, low pressure is created at and below the head of the bolus. A modest pressure increase is seen as the bolus passes through the pharynx and finally, high pressure is observed at the bolus tail, followed by an even larger pressure generation of a clearance event. HRM allows for greater resolution in data collection in the pharynx and in this study, aided in identifying semi unique characteristics around the hypopharynx and the UES which are consistent with the complex anatomy of the regions and the transition of the UES from active closure to relaxed opening. In the future, additional studies designed to look at aged and diseased populations may lead to better understanding of disease etiology, and treatment options.

Characterization of pharyngeal peristaltic pressure variability during volitional swallowing in healthy individuals

“…7,11,14 Findings of the present study are in general concordance with these earlier reports regarding the magnitude of pharyngeal peristaltic pressure waves.…”

Pharyngeal swallowing mechanics associated with upper esophageal sphincter pressure wave

“…Flat 2 in Figure muscles at approximately the time of Incline 1, emphasizing their role prior to the decrease in UES pressure; the authors also comment on deactivation of cricopharyngeus after manometric relaxation begins, supporting the idea that the UES actively maintains a seal through the point of opening. 6,25,26 The utility of the formation of an enclosed pharyngeal chamber could have significant implications for head and neck surgeons and speech-language pathologists when evaluating patients with mechanical issues that prevent closure of any of the four pharyngeal outlets. 6,25,26 The utility of the formation of an enclosed pharyngeal chamber could have significant implications for head and neck surgeons and speech-language pathologists when evaluating patients with mechanical issues that prevent closure of any of the four pharyngeal outlets.…”

“…The UES is closed at rest, resulting in a region of high pressure on manometry due primarily to the tonic contraction of the cricopharyngeus. [6][7][8] Existing literature describes the UES pressure wave during swallowing as an elevated resting (basal) pressure, a period of low pressure (relaxation), a post-deglutitive increase in pressure, and a return to resting pressure. There are three physiological events that contribute to UES opening: (a) inhibition of the cricopharyngeus, 1,2 (b) elevation of the hyolaryngeal complex resulting in traction on the UES, [3][4][5] and (c) generation of pharyngeal pressure resulting from valve closures and pharyngeal shortening and constriction.…”

The pharyngeal contractile integral is a useful indicator of pharyngeal swallowing impairment

“…The average mid-bolus pressure in the hypopharyngeal region was much lower at 3.14 (+/− 1.36). 13 Given the range of approximately 15 – 35 mmHg for the highest region of mid-bolus pressure, we felt that a benchmark of 20 mmHg was appropriate and likely any pressures below that were not significant contributors to PhCI. The authors acknowledge that pharyngeal IBP could be increased in settings of outflow obstruction, such as seen in cricopharyngeal dysfunction.…”