Blood VolumePlasma VolumeHypovolemiaErythrocyte VolumeCerebrovascular CirculationHematocritPlasma SubstitutesMagnetic Resonance ImagingHemodynamicsStroke VolumeFluid ShiftsRegional Blood FlowLung Volume MeasurementsCardiac OutputBrainBlood PressurePulmonary Diffusing CapacityHemorrhageOxygenContrast MediaBlood Flow VelocityHemodilutionHemoglobinsBlood CirculationDye Dilution TechniqueTime FactorsReproducibility of ResultsIsotonic SolutionsHydroxyethyl Starch DerivativesSpectroscopy, Near-InfraredImage Processing, Computer-AssistedShock, HemorrhagicPerfusion ImagingDogsIndocyanine GreenMagnetic Resonance AngiographyPulmonary CirculationBlood Volume DeterminationOxygen ConsumptionOxygen RadioisotopesTomography, X-Ray ComputedVascular CapacitanceGadolinium DTPAHeart RateTomography, Emission-ComputedHypotensionMicrocirculationFluid TherapySensitivity and SpecificityThoraxVascular ResistanceBrain NeoplasmsCarbon DioxideImage Interpretation, Computer-AssistedExchange Transfusion, Whole BloodOrgan SizePlethysmographyImage EnhancementPolygelineImaging, Three-DimensionalWater-Electrolyte BalanceSplanchnic CirculationReference ValuesCentral Venous PressureIndicator Dilution TechniquesForced Expiratory VolumeAcetazolamideLiver CirculationCarbon MonoxidePostureColoring AgentsDiuresisBrain IschemiaLungPressureTechnetiumAnalysis of VarianceAlgorithmsRats, Sprague-DawleyCapillariesSupine PositionSaline Solution, HypertonicBody WaterProspective StudiesEcho-Planar ImagingBlood Gas AnalysisValsalva ManeuverCapillary PermeabilityPressoreceptorsDisease Models, AnimalVasopressinsMicrovesselsPlethysmography, ImpedanceShockVeinsHyperventilationResuscitationModels, BiologicalGliomaSodium Chloride