Pumping Patterns and Work Done during Peristalsis in Finite-length Elastic Tubes

TL;DR

This study develops a simplified 1D model to analyze peristaltic pumping in elastic tubes, comparing it with detailed 3D simulations, and applies it to interpret clinical data for esophageal function assessment.

Contribution

The paper introduces a reduced order 1D model for peristaltic pumping that aligns with 3D simulations and extends to clinical data analysis, providing new insights into work done during peristalsis.

Findings

The 1D model accurately captures major dynamics observed in 3D simulations.

Different pumping regimes exhibit unique elastic energy and work signatures.

The model aids in interpreting clinical data and quantifying esophageal pumping capacity.

Abstract

Balloon dilation catheters are often used to quantify the physiological state of peristaltic activity in tubular organs and comment on their ability to propel fluid which is important for healthy human function. To fully understand this system's behavior, we analyzed the effect of a solitary peristaltic wave on a fluid-filled elastic tube with closed ends. A reduced order model that predicts the resulting tube wall deformations, flow velocities and pressure variations is presented. This simplified model is compared with detailed fluid-structure 3D immersed boundary simulations of peristaltic pumping in tube walls made of hyperelastic material. The major dynamics observed in the 3D simulations were also displayed by our 1D model under laminar flow conditions. Using the 1D model, several pumping regimes were investigated and presented in the form of a regime map that summarizes the system's response for a range of physiological conditions. Finally, the amount of work done during a peristaltic event in this configuration was defined and quantified. The variation of elastic energy and work done during pumping was found to have a unique signature for each regime. An extension of the 1D model is applied to enhance patient data collected by the device and find the work done for a typical esophageal peristaltic wave. This detailed characterization of the system's behavior aids in better interpreting the clinical data obtained from dilation catheters. Additionally, the pumping capacity of the esophagus can be quantified for comparative studies between disease groups.