Oxygen concentrators performance with nitrous oxide at 50:50 volume

AbstractBackground and objectivesFew investigations have addressed the safety of oxygen from concentrators for use in anesthesia in association with nitrous oxide. This study evaluated the percent of oxygen from a concentrator in association with nitrous oxide in a semi-closed rebreathing circuit.MethodsAdult patients undergoing low risk surgery were randomly allocated into two groups, receiving a fresh gas flow of oxygen from concentrators (O293) or of oxygen from concentrators and nitrous oxide (O293N2O). The fraction of inspired oxygen and the percentage of oxygen from fresh gas flow were measured every 10min. The ratio of FiO2/oxygen concentration delivered was compared at various time intervals and between the groups.ResultsThirty patients were studied in each group. There was no difference in oxygen from concentrators over time for both groups, but there was a significant improvement in the FiO2 (p<0.001) for O293 group while a significant decline (p