title: Inspired O2 and N2O concentrations in essentially closed circuits.
abstract: By simulation of the FRC (functional residual capacity), washin of N2O was conceptually separated from uptake at the alveolar-capillary membrane. Data collected by mass spectrometry and pneumotachography during a period of 2 years showed a near-constant body uptake of N2O which makes clinical application of closed circuit N2O--O2 anesthesia simple and safe. The data failed to confirm accelerated washin by higher concentrations of N2O ("the concentration effect"), although there was a concentrating effect according to the law of mass action.
mesh_terms: D000388:Air / Q000032:analysis*; D000769:Anesthesia, Inhalation / Q000295:instrumentation; D006801:Humans; D013058:Mass Spectrometry; D009609:Nitrous Oxide / Q000032:analysis*; D010100:Oxygen / Q000032:analysis*
chemical_list: D009609:Nitrous Oxide; D010100:Oxygen