A fluid mechanical perspective on esophageal bolus transport

Abstract

A fluid mechanical description of peristaltic esophageal transport is presented in pedagogical form, without equations and with minimal technical jargon, using simple theoretical models of peristaltic pumping. In the most basic model, a viscous fluid is transported along a tube of circular cross-section by periodic sinusoidal contractions of the tube wall. From this model the primary mechanisms of fluid transport are discerned, and an analysis is made of the proximal leakage of bolus fluid that results from incomplete luminal contraction. A modification of the theoretical model is described next, in which a fluid layer with viscosity different than the bolus fluid is placed adjacent to the tube wall to simulate the effect of a mucous coating in esophageal transport. With this model it is discovered that, when leakage can occur, a coating of low viscosity increases the amount of leakage and reduces net transport. Finally, the theory is applied to peristaltic wave characteristics that are more representative of esophageal bolus transport; and intrabolus pressures, computed using radiographic data of bolus shapes as input, are compared with manometric measurement.