Pulmonary AlveoliLungRespiration, ArtificialVentilationPulmonary VentilationLung DiseasesHigh-Frequency VentilationTidal VolumePositive-Pressure RespirationIntermittent Positive-Pressure VentilationLung InjuryRespiratory MechanicsRespirationPulmonary Gas ExchangeLung NeoplasmsHigh-Frequency Jet VentilationNoninvasive VentilationLung Volume MeasurementsVentilator WeaningRespiratory Distress Syndrome, AdultVentilators, MechanicalAcute Lung InjuryVentilator-Induced Lung InjuryCarbon DioxidePulmonary SurfactantsVentilation-Perfusion Ratio