• deglutition;
  • dysphagia;
  • evaluation;
  • FLIP;
  • swallowing;
  • upper esophageal sphincter


Background  This paper aims to measure upper esophageal sphincter (UES) distensibility and extent and duration of UES opening during swallowing in healthy subjects using EndoFLIP®.

Methods  Fourteen healthy subjects (20–50 years) were recruited. An EndoFLIP® probe was passed trans-orally and the probe balloon was positioned across the UES. Two 20-mL ramp distensions were completed and UES cross-sectional area (CSA) and intra-balloon pressure (IBP) were evaluated. At 12-mL balloon volume, subjects completed dry, 5- and 10-mL liquid swallows and extent (mm) and duration (s) of UES opening and minimum IBP (mmHg) were analyzed across swallows.

Key Results  Thirteen subjects completed the study protocol. A significant change in UES CSA (< .001) and IBP (< .000) was observed during 20-mL distension. UES CSA increased up to 10-mL distension (< .001), from which point IBP raised significantly (= 0.004). There were significant changes in UES diameter (mm) (< .000) and minimum IBP (mmHg) (< .000) during swallowing events. Resting UES diameter (4.9 mm; IQR 0.02) and minimum IBP (18.8 mmHg; IQR 2.64) changed significantly during dry (9.6 mm; IQR 1.3: < .001) (3.6 mmHg; IQR 4.1: = 0.002); 5 mL (8.61 mm; IQR 2.7: < .001) (4.8 mmHg; IQR 5.7: < .001) and 10-mL swallows (8.3 mm; IQR 1.6: < 0.001) (3 mmHg; 4.6: < .001). Median duration of UES opening was 0.5 s across dry and liquid swallows (= 0.91). Color contour plots of EndoFLIP® data capture novel information regarding pharyngo-esophageal events during swallowing.

Conclusions & Inferences  Authors obtained three different types of quantitative data (CSA, IBP, and timing) regarding UES distensibility and UES opening patterns during swallowing in healthy adults using only one device (EndoFLIP®). This new measure of swallowing offers fresh information regarding UES dynamics which may ultimately improve patient care.