CFD Analysis of Flow Characteristics in a Jet Laryngoscope and the Different Application Forms of Superimposed Jet Ventilation

Abstract

The superimposed high-frequency jet ventilation is a jet ventilation technique that allows the surgeon to operate in a system open to the outside endoscopic surgery in the area of the vocal cord level. Although the clinical application is uncomplicated, the possible mechanisms of the gas flow in the jet laryngoscope are largely unknown. In the performed calculations for this work, the CFD software package Fluent is used with the preprocessor GAMBIT. After creating the geometry and networking of the jet laryngoscope in the preprocessor GAMBIT, the boundary conditions and input parameters in the solver are defined. This is followed by iterative calculation using Fluent and the tabulation of results. Ventilation is provided by an electronic respirator specially developed for the endoscope. There is a bidirectional gas flow in the jet laryngoscope. The free jet characteristics of the jet beam can be confirmed. Entrainment depends on pressure and on the gas velocity. The arrangement of the nozzles enables jet ventilation in stenosis. CFD analysis enables the representation of a continuous progress of the pressure as well as the representation of the continuous profile of the velocity in the investigated endoscope. Additionally the practical application for intensive care ventilation is shown.