Supine PositionProne PositionPatient PositioningPostureTilt-Table TestHead-Down TiltHeart RateSupinationHypotension, OrthostaticNephrostomy, PercutaneousGravitationBlood PressureRespiratory MechanicsAutonomic Nervous SystemRespirationIndoraminValsalva ManeuverSyncopeBaroreflexPressureDizzinessMovementHemodynamicsSyncope, VasovagalExpiratory Reserve VolumeCardiac OutputTidal VolumeSudden Infant DeathLegPulmonary Gas ExchangeFluid ShiftsLung Volume MeasurementsPalate, SoftTechnetium Tc 99m Aggregated AlbuminEsophageal pH MonitoringPulmonary CirculationEsophagusHeadRestReference ValuesOxygenSleepThoracic WallSleep ParalysisFunctional Residual CapacityBlood Flow VelocityInhalationRibsDiaphragmLungAutonomic Nervous System DiseasesPharynxTime FactorsBedsVentilators, Negative-PressureAirway ResistanceCarbon DioxidePlethysmographyCentral Venous PressurePneumoperitoneum, ArtificialElectrocardiographyLymphatic IrradiationEsophageal Motility DisordersRegional Blood FlowVenous PressurePelvisMolecular Sequence DataAirway ObstructionVeinsPulmonary VentilationTongueRespiratory MusclesTotal Lung CapacityBlood VolumeSleep Apnea, ObstructiveVascular ResistanceSpineAnesthesia, SpinalRespiration, ArtificialIntraocular PressureTonometry, OcularPolysomnographyOropharynxProspective StudiesNeckJugular VeinsExercise TestRespiratory Distress Syndrome, AdultBlood Gas AnalysisSnoringSphygmomanometersExerciseReproducibility of ResultsThoraxRespiratory Function TestsSympathetic Nervous SystemSignal Processing, Computer-AssistedTomography, X-Ray ComputedAbdomenSleep Apnea Syndromes