Venous PressureCentral Venous PressurePerfusionPressureBlood PressurePerfusion ImagingPortal PressureHydrostatic PressureHemodynamicsBlood Pressure DeterminationMyocardial Perfusion ImagingTransducers, PressureHypertension, PortalRegional Blood FlowCapillary ResistanceIntracranial PressureVascular ResistanceHeart RateBlood VolumeDogsJugular VeinsIntraocular PressureCardiac OutputVeinsHypertensionLiver CirculationPulmonary Wedge PressureHepatic VeinsCoronary CirculationArterial PressureBlood Flow VelocityCerebrovascular CirculationTime FactorsPlasma SubstitutesVenous InsufficiencyBlood Pressure Monitoring, AmbulatoryHeartPlethysmographySplanchnic CirculationPortal VeinTomography, Emission-Computed, Single-PhotonFluid TherapyVascular CapacitanceLower Body Negative PressureMonitoring, IntraoperativeBlood CirculationPostureAir PressureAtmospheric PressureCerebrospinal Fluid PressureHypovolemiaSympathetic Nervous SystemChemotherapy, Cancer, Regional PerfusionMicrocirculationLiver CirrhosisPulmonary CirculationSupine PositionTourniquetsOxygenVentricular PressureEsophageal and Gastric VaricesLegMonitoring, PhysiologicPressoreceptorsPortal SystemHypotensionProspective StudiesAnesthesiaAntihypertensive AgentsIsotonic SolutionsHydroxyethyl Starch DerivativesConstrictionOsmotic PressureVasodilator AgentsHead-Down TiltFemoral VeinComplianceModels, CardiovascularCollateral CirculationPositive-Pressure RespirationReflexDiastoleScleraArteriesCarbon DioxideTreatment OutcomeVaricose VeinsAnesthesia, GeneralRespirationKidneyPulmonary ArteryBaroreflexReproducibility of ResultsVasoconstrictionRats, Sprague-DawleyNorepinephrineOxygen ConsumptionBlood Volume DeterminationTechnetium Tc 99m SestamibiVena Cava, Superior