Airway ObstructionTracheal StenosisBronchial DiseasesBronchoscopyAirway ResistanceTracheal DiseasesBronchiTracheal NeoplasmsIntestinal ObstructionLaryngostenosisTracheobronchomalaciaTracheomalaciaRespiratory Function TestsForced Expiratory VolumeLungRespiratory SystemAsthmaUreteral ObstructionLung Diseases, ObstructiveBronchoconstrictionTracheaLaryngeal DiseasesSpirometryAirway RemodelingVital CapacityLaser TherapyNasal ObstructionStentsConstriction, PathologicTomography, X-Ray ComputedBronchitisPierre Robin SyndromeDuodenal ObstructionBronchial HyperreactivityPlethysmography, Whole BodyMaximal Expiratory Flow-Volume CurvesLung NeoplasmsPulmonary VentilationUrinary Bladder Neck ObstructionSmokingUrethral ObstructionBronchial Provocation TestsBronchodilator AgentsPulmonary Disease, Chronic ObstructiveGastric Outlet ObstructionRespiratory MechanicsTotal Lung CapacityVentricular Outflow ObstructionTracheotomyTreatment OutcomeResidual VolumeRespiratory MucosaIntubation, IntratrachealHeliumLung Volume Measurements