Prone PositionSupine PositionPatient PositioningPostureNephrostomy, PercutaneousRespiratory Distress Syndrome, AdultPulmonary Gas ExchangeSudden Infant DeathRespiratory MechanicsRespiration, ArtificialGravitationPulmonary CirculationDisposable EquipmentPositive-Pressure RespirationTilt-Table TestBedsVentilation-Perfusion RatioNitrogen RadioisotopesHead-Down TiltSpineRespirationSleepPronationPulmonary VentilationLaryngopharyngeal RefluxHeart RateOrgans at RiskLung Volume MeasurementsBlood Gas AnalysisSupinationOxygenHypotension, OrthostaticLungIntubation, IntratrachealProspective StudiesUreteral CalculiHemodynamicsTomography, X-Ray ComputedEquipment ReuseLaryngeal MasksAirway ManagementBlood PressureIntraoperative ComplicationsMolecular Sequence DataPressure UlcerTime FactorsRespiratory Function Tests