Supine PositionPostureProne PositionPatient PositioningGravitationLevobunololAcepromazineHeart RateRespirationMovementInteractive Ventilatory SupportRespiratory MechanicsIntra-Abdominal HypertensionTidal VolumePolysomnographyPulmonary Gas ExchangeTilt-Table TestPressureBlood PressureHead-Down TiltSleepSleep Apnea, ObstructiveIntraocular PressureBiomechanical PhenomenaSupinationHypotension, OrthostaticOxygenSleep Apnea SyndromesSwimmingTime FactorsNephrostomy, PercutaneousSleep, REMElectric ImpedanceMolecular Sequence DataReproducibility of ResultsElectromyographyProspective StudiesAutonomic Nervous SystemAnalysis of VarianceIndoraminValsalva ManeuverSyncopeBaroreflexAmino Acid SequenceDizzinessBase SequenceHemodynamicsSyncope, VasovagalSudden Infant DeathHeadCardiac OutputExpiratory Reserve VolumeLegFluid ShiftsLung Volume MeasurementsPalate, SoftReference ValuesEsophagusTechnetium Tc 99m Aggregated AlbuminPulmonary CirculationEsophageal pH MonitoringRestThoracic WallSleep ParalysisFunctional Residual CapacityBlood Flow VelocityRibsBedsInhalationLungDiaphragmPharynxCarbon DioxideAutonomic Nervous System DiseasesPlethysmographyAirway ResistancePneumoperitoneum, ArtificialVentilators, Negative-PressureCentral Venous PressurePelvisElectrocardiographyTongueRegional Blood FlowVenous PressureLymphatic IrradiationAirway ObstructionEsophageal Motility DisordersVeinsPulmonary VentilationRespiratory MusclesSpine