Journal of clinical anesthesia
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To determine if the laryngeal mask airway (LMA) seal is maintained during surgery, to evaluate the safety of an LMA leak test, and to determine the time course of the increase in LMA cuff pressure in vivo in the presence of nitrous oxide (N2O). ⋯ The LMA leak test can be safely performed. The airway seal provided by the LMA is well maintained during surgery. The increase in LMA cuff pressure during surgery in the presence of N2O is small and probably is not a cause for clinical concern. If positive pressure is to applied in the presence of an LMA, one should limit this pressure to below the LMA leak pressure so as to lower the risk of inflating the stomach with gas that may than leak around the LMA.
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To predict the inspired concentrations achieved when nitrous oxide (N2O)/oxygen mixtures are administered to patients by way of a nasal cannula. ⋯ Our analysis shows that the maximum FiN2O achievable by using a nasal cannula is limited to 0.21 even with a 6 L/min flow of 70% N2O for the defined respiratory parameters.