Pulmonary AlveoliPulmonary AtelectasisLungOxygenRespiration, ArtificialMiddle Lobe SyndromeOxygen ConsumptionReactive Oxygen SpeciesPulmonary Gas ExchangePartial PressureBronchoscopyLung CompliancePositive-Pressure RespirationLung Volume MeasurementsPulmonary SurfactantsBronchial NeoplasmsAnesthesia, General