Observational Study of Dynamic Ventilation Parameters during Xenon Anesthesia

Background: The aim of this study was to observe dynamic pressure and flow measurements during the breathing cycle with different concentrations of xenon in patients without pulmonary disease to provide a better understanding of the mechanical-physiological effects of gas mixtures for anesthesia and other potential applications. Ventilation and respiratory data monitoring of flow rate, pressure at the Y-piece of the ventilator circuit, inhaled volume, and concentration of oxygen, xenon, and carbon dioxide for three concentrations of xenon (0, 30, and 60%) were recorded on the anesthetic ventilator station and downloaded to a portable computer. Main Findings: The overall effects of gas concentration are compared in the superimposed flow and pressure curves recorded from the ventilator. Airway resistance increases with xenon concentration for both inspiration (p=0.0028) and expiration (p=0.0007) as expected. The compliance increased with increasing xenon concentration, but only to statistical significance between 100% oxygen and 60% xenon (p=0.0344). The percentage of pressure drop due to the breathing circuit were about 70% for all the groups (no differences statistically, p=0.8161). Conclusions: The results show that the dominant source of the pressure loss is from the breathing circuit compared to the respiratory tract in patients without respiratory disease during inspiration.