Supine PositionPostureProne PositionPatient PositioningSleep Apnea, ObstructiveSleep Apnea SyndromesPolysomnographyGravitationLevobunololRespirationHeart RateAcepromazineRespiratory MechanicsSleep Apnea, CentralInteractive Ventilatory SupportMovementSleepTidal VolumeIntra-Abdominal HypertensionPressurePulmonary Gas ExchangeTilt-Table TestBlood PressureOxygenHead-Down TiltSleep, REMIntraocular PressureBiomechanical PhenomenaSnoringSupinationHypotension, OrthostaticPalate, SoftTime FactorsSwimmingNephrostomy, PercutaneousContinuous Positive Airway PressureElectric ImpedanceElectromyographyPharynxProspective StudiesAutonomic Nervous SystemAnalysis of VarianceReproducibility of ResultsMolecular Sequence DataValsalva ManeuverTongueAirway ObstructionIndoraminPositive-Pressure RespirationBaroreflexSudden Infant DeathPulmonary VentilationFluid ShiftsHemodynamicsExpiratory Reserve VolumeSyncopeCarbon DioxideAirway ResistanceAmino Acid SequenceDizzinessCardiac OutputHeadBase SequenceInhalationReference ValuesSyncope, VasovagalLegLung Volume MeasurementsOropharynxUvulaMandibular AdvancementEsophagusWakefulnessEsophageal pH MonitoringDiaphragmPulmonary CirculationNeckVentilators, Negative-PressureRestTechnetium Tc 99m Aggregated AlbuminLungRespiratory MusclesBedsFunctional Residual CapacityAnoxiaElectrocardiographyBlood Gas AnalysisBlood Flow VelocityAutonomic Nervous System DiseasesThoracic WallSleep ParalysisRibsSeverity of Illness IndexRespiration, ArtificialRegional Blood FlowMonitoring, PhysiologicPlethysmographySympathetic Nervous SystemPneumoperitoneum, ArtificialCentral Venous Pressure