Blood VolumeBlood PressurePlasma VolumeHypovolemiaErythrocyte VolumeHypertensionCerebrovascular CirculationSystoleHemodynamicsHematocritHeart RatePlasma SubstitutesMagnetic Resonance ImagingStroke VolumeCardiac OutputHypotensionRegional Blood FlowTime FactorsFluid ShiftsBlood Flow VelocityLung Volume MeasurementsAntihypertensive AgentsRisk FactorsBrainBlood CirculationHemorrhageProspective StudiesPulmonary Diffusing CapacityReproducibility of ResultsOxygenHemoglobinsHemodilutionBlood Pressure DeterminationDye Dilution TechniqueContrast MediaVascular ResistanceShock, HemorrhagicIsotonic SolutionsHydroxyethyl Starch DerivativesSpectroscopy, Near-InfraredReference ValuesBody WeightOrgan SizeOxygen ConsumptionPerfusion ImagingImage Processing, Computer-AssistedReninHypotension, OrthostaticPulseMagnetic Resonance AngiographyRegression AnalysisDogsIndocyanine GreenTomography, X-Ray ComputedDiastolePlethysmographyAnalysis of VariancePulmonary CirculationPredictive Value of TestsFluid TherapyFollow-Up StudiesBlood Volume DeterminationCardiovascular SystemKidneyPostureMicrocirculationOxygen RadioisotopesLinear ModelsBlood Pressure Monitoring, AmbulatoryCardiovascular DiseasesSensitivity and SpecificityVascular CapacitanceGadolinium DTPARats, Inbred SHRTomography, Emission-ComputedCentral Venous PressureValsalva ManeuverTreatment OutcomeSupine PositionBody Mass IndexPlethysmography, ImpedanceRats, Sprague-DawleySodium ChlorideCohort StudiesThoraxCardiovascular Physiological PhenomenaTilt-Table TestDiuresisSplanchnic CirculationWater-Electrolyte BalanceExerciseCarbon DioxideHeartBaroreflexExchange Transfusion, Whole BloodPressoreceptorsShockBrain NeoplasmsComplianceBrain Ischemia