Airway pressure distribution during xenon anesthesia: The insufflation phase at constant flow (volume controlled mode)

There is an increase in pressure necessary to drive xenon insufflation due to increased flow resistance that results from the elevated density and viscosity of xenon-oxygen mixtures. It had been suggested that these higher pressures could be clinically relevant, though results from animal experiments demonstrate otherwise. Numerical simulations in a healthy adult morphology were performed to investigate how these elevated pressures are distributed within the respiratory tract and patient interface as a function of gas concentration, flow rate and endotracheal tube size. The results confirm that there is indeed an increase in pressure needed to drive xenon anesthesia compared to air or oxygen ventilation and that the differences occurred primarily across the endotracheal tube and were found to be much less significant within the lung itself. For all parameters studied, pressure differences between xenon-oxygen and air or oxygen ventilation were found to be negligible in the acinus for the healthy adult male morphology considered, indicating that the increased pressure at the ventilator to drive xenon insufflation is dissipated in the artificial breathing circuit.