Pulmonary Gas ExchangeVentilation-Perfusion RatioRespiratory Dead SpacePulmonary VentilationPulmonary AlveoliRespiration, ArtificialCarbon DioxideTidal VolumeRespirationRespiratory MechanicsBlood Gas AnalysisPartial PressureVentilationPulmonary CirculationNitrogen RadioisotopesMacrophages, AlveolarOxygenRespiratory Function TestsRespiratory InsufficiencyLungHigh-Frequency VentilationAnoxiaIntermittent Positive-Pressure VentilationPositive-Pressure RespirationOxygen ConsumptionHigh-Frequency Jet VentilationNoninvasive VentilationVentilator WeaningAlveolar ProcessVentilators, MechanicalModels, BiologicalPulmonary Alveolar ProteinosisRespiratory Distress Syndrome, AdultIntubation, IntratrachealHypercapniaVentilator-Induced Lung InjuryLung ComplianceAlveolar Bone LossRhabdomyosarcoma, AlveolarWork of BreathingPulmonary SurfactantsHeliumPulmonary EdemaLung Volume MeasurementsTracheostomyBronchoalveolar Lavage FluidAir PressureLung DiseasesLung InjuryOne-Lung VentilationRespiratory Distress Syndrome, NewbornAcute Lung InjuryIntensive Care UnitsLaryngeal MasksMaximal Voluntary VentilationVentilators, Negative-PressureMasksAirway ResistanceHypoventilationIntensive CareTime FactorsTracheotomyPneumocytesRespiratory RateProne PositionRespiratory Physiological PhenomenaPulmonary AtelectasisBronchoalveolar LavageApneaDiaphragmHyperoxiaOxygen Inhalation TherapyBarotraumaInhalationIntermittent Positive-Pressure BreathingHyperventilationRespiratory MusclesFunctional Residual CapacityAirway ObstructionKrypton RadioisotopesInfant, NewbornAnesthesia, GeneralKryptonLung Diseases, ObstructiveChemoreceptor CellsPneumoniaCritical IllnessRespiratory MucosaAirway ExtubationAerosolsAir ConditioningPressureProspective StudiesAdministration, InhalationCapnographyMandibular NerveInteractive Ventilatory SupportCritical CarePulmonary Disease, Chronic ObstructiveAnesthetics, Inhalation