Interpretation of intraluminal manometric measurements in terms of swallowing mechanics

Abstract

A unified discussion of the mechanics of the swallowing process, and its interpretation through manometric measurements of intraluminal pressure, are presented in this paper. The goals of the discussions are to provide the reader with basic knowledge of pharyngeal, esophageal, and sphincter mechanics; to relate the mechanical processes to intraluminal pressure recordings; and to clarify the relationship between intraluminal pressure and esophageal muscle contractile behavior. The esophageal phase of bolus transport, in particular, is discussed in some detail due to the relatively simple geometry and the straightforward description of peristalsis and muscle mechanics in this region. Several important issues are emphasized in the discussion. For example, pressure variation within a static bolus is fundamentally different from that within a moving bolus. Manometric recordings must be interpreted accordingly. The importance of differentiating between "hydrodynamic pressure," which is pressure measured within a fluid bolus, and "contact pressure," which is the direct squeeze of the luminal wall on the manometric port in a region devoid of bolus fluid, is discussed in some detail. We argue that pressure "amplitude" does not, in principle, give any indication of the forces required to drive the fluid bolus forward. What should be sought is the variation of intrabolus pressure relative to the contact pressure, particularly during periods in which the contractile segment fails to obliterate the esophageal lumen. Examples of intraluminal pressure recording in the esophagus, using manometry and mathematical models, are presented to demonstrate both the possibilities and the difficulties of interpreting manometric recordings in the absence of concurrent radiographic imaging. We discover that in regions of nearly complete luminal closure, the pressure signature and bolus geometry are strongly coupled during peristaltic transport, providing the possibility that in these regions quantitative measures of muscle performance might be developed without the need for radiographic imaging. On the other hand, the ambiguity in the interpretation of manometric recordings that often accompanies dysphagic conditions suggests that as more sophisticated interpretations are sought, manometry concurrent with radiography will play a more prominent role in patient evaluation.

Electro-kinetically driven peristaltic transport of viscoelastic physiological fluids through a finite length capillary: Mathematical modeling

“…An excellent example is the study of Li and Brasseur [22] who considered both single and multiple train wave propagation. Brasseur and Dodds [23] described numerical results which concur well with the manometer observation for swallowing of a single food bolus. These studies while physically more realistic than earlier analyses, have nevertheless been confined to the Newtonian i.e.…”

Axial force measurement for esophageal function testing

“…However, any contraction -strong or weak -will only be measured by manometry if it occludes the measuring catheter. Using data from computer models, it has been argued that shortening of the longitudinal muscle plays an important role in the mechanisms of peristalsis and that pressure amplitude per se does not give any indication of the force required to drive the bolus forward [4] . Hence manometric recordings alone are insufficient to describe and quantify esophageal motility.…”

The effects of tegaserod on oesophageal function and bolus transport in healthy volunteers: studies using concurrent high‐resolution manometry and videofluoroscopy

“…[10][11][12] Thirdly, high-resolution pressure measurement provides an assessment of intra-bolus pressure and the propulsive force that drives bolus transport (pressure gradient). 13,14 As a result, HRM improves the ability of investigators to describe the physiological basis for the success or failure of bolus transport; 15 an important advantage because oesophageal symptoms and mucosal damage are more closely related to bolus transport and reflux clearance than abnormal motor function as assessed by conventional manometry. 16,17 This randomized, placebo controlled, double-blind trial studied the effect of tegaserod on the oesophagus in healthy, asymptomatic subjects.…”