Ventilation-Perfusion RatioPulmonary Gas ExchangeGasesCarbon DioxideNoble GasesAbsorbent PadsOxygenBlood Gas AnalysisPartial PressurePulmonary CirculationWater Loss, InsensiblePlant TranspirationRespiratory MechanicsOxygen ConsumptionRespirationRespiratory Dead SpaceLungRespiration, ArtificialLiquid VentilationPulmonary VentilationRespiratory Distress Syndrome, AdultPhotosynthesisPlant StomataTidal VolumePlant LeavesMild Cognitive ImpairmentCognition DisordersRespiratory InsufficiencyRespiratory Function TestsChromatography, GasPositive-Pressure RespirationPulmonary Diffusing CapacityGas Chromatography-Mass SpectrometryDeuterium Exchange Measurement