Multichannel pressure, bolus transit, and pH esophageal catheter

Esophageal motility disorders are diagnosed by monitoring pressure, pH, and bolus transit in the lumen of the organ. However, an integrated multichannel esophageal catheter capable of monitoring all these phenomena in a single clinical test is still lacking. The present work proposes innovative techniques and methods to develop a multichannel integrated esophageal catheter. A novel optical pressure sensor for lower esophageal sphincter location and pressure monitoring is proposed. Proper selection of frequencies and electrode arrangement allows impedance-based monitoring of pH and bolus transit. Moreover, due to the small size of the proposed impedance electrode configuration, monitoring channels can be located at 3-mm intervals, improving the longitudinal resolution of the catheter. Therefore, impedance-based pH level monitoring is now feasible. The proposed optical method for pressure monitoring was evaluated by applying pressure around the designed sensor. Obtained images showed good correlation with applied pressures. A model of the esophagus that mimics esophageal motility was utilized to test the proposed catheter. Repeatability of the impedance measurements related to pH was evaluated. The obtained results satisfied the requirements of the DeMeester and Johnson scoring system for esophageal pH measurements. Gastro-esophageal reflux was simulated in the test model and successfully measured with a spatial resolution of 3-mm. Bolus transit was also simulated and successfully identified. All experimental results demonstrated the feasibility of the proposed design. This innovative catheter overcomes many of the disadvantages of the conventional techniques for esophageal testing, but clinical trials are necessary to verify the validity of the laboratory results