Interpretation of pharyngeal manometric recordings: Limitations and variability

Manometric tracings from eight equidistant axial locations in the pharynx were examined in eight normal subjects along with simultaneous videofluoroscopy. Resting and midswallow sensor position was tracked and categorized into one of four anatomical locations: retropalatal, retrolingual, hypopharyngeal and upper esophageal sphincter (UES). Tracings were examined for wave amplitude, duration, and interval to 1/2 maximal pressure. Composite recordings were reconstructed corresponding to these zones. Modification of the pharyngeal contraction was examined using variables of volume, viscosity, and temperature. Variation in pha ryngeal anatomy with resting pharyngeal length ranging from 7-13 cm was observed causing substantial diversity in functional segment length. Manometric attributes and morphology of composite tracings varied with pharyngeal location. Contraction amplitudes and wave duration were unaffected by bolus volume although amplitude increased with the most viscous substance. No change was seen with iced boluses and no effect upon the propagation of the pharyngeal contraction was noted with any bolus variable. In conclusion, the difficulties in determining the position of a manometer within the pharynx without fluoroscopic aid argue strongly for the use of combined manometric and fluoroscopic recordings when deglutitive pressure data are required. Only when anatomic position is suitably controlled can comparable data be obtained among subjects.