Esophageal Biomechanics: Work, Power, and Modulus using Impedance-Manometry
The esophagus is a vital gastrointestinal organ that transports food and liquid from the mouth to the stomach. When its function is disrupted, swallowing issues can result, which can lead to serious degradation in quality of life, malnutrition, and starvation if not properly treated. The aim of this work was to examine the mechanical function of the esophagus during swallowing in patients with clinically relevant dysphagia.Two steps were taken to achieve this: In Chapter 2, a new test was developed based on standard clinical High Resolution Impedance Manometry (HRIM). A new swallow testing material is introduced which allows for the electrical impedance signals to be used to estimate the cross-sectional area (CSA) of the esophagus while material is traveling through it. Then in Chapter 3, both the pressure and CSA information from the new HRIM test is used to calculate the work, power, and elastic modulus of the esophagus during a swallow. This investigation was performed on patients with dysphagia and two groups without dysphagia (controls). In summary, it was found that the esophagi of the patients with dysphagia generated a lower amount of work and power than the controls. There also were differences in the elastic modulus, which were distinct per disease groups. These results are reflective of the decreased esophageal motor function seen in patients with dysphagia. This work adds to our understanding of esophageal physiology and pathophysiology by developing a mechanical model of the esophagus during primary peristalsis. Here the esophagus is assessed as a cylinder using standard engineering metrics of Work (in units of Joules) and Power (in units of Watts) during a swallow cycle. These advancements could lead to sophisticated and complex models of the esophagus which could play an important part in esophageal diagnostics and targeted therapeutics.