Blood VolumePlasma VolumeHypovolemiaErythrocyte VolumeCerebrovascular CirculationHematocritPlasma SubstitutesMagnetic Resonance ImagingHemodynamicsStroke VolumeFluid ShiftsLung Volume MeasurementsRegional Blood FlowCardiac OutputBlood PressurePulmonary Diffusing CapacityBrainHemorrhageHemodilutionBlood CirculationDye Dilution TechniqueContrast MediaBlood Flow VelocityHemoglobinsIsotonic SolutionsHydroxyethyl Starch DerivativesOxygenSpectroscopy, Near-InfraredShock, HemorrhagicReproducibility of ResultsPerfusion ImagingImage Processing, Computer-AssistedIndocyanine GreenPulmonary CirculationMagnetic Resonance AngiographyTime FactorsBlood Volume DeterminationDogsOxygen RadioisotopesVascular CapacitanceGadolinium DTPAOxygen ConsumptionTomography, X-Ray ComputedTomography, Emission-ComputedHypotensionFluid TherapyHeart RateThoraxMicrocirculationVascular ResistanceExchange Transfusion, Whole BloodBrain NeoplasmsPlethysmographyImage Interpretation, Computer-AssistedPolygelineCarbon DioxideSensitivity and SpecificityImage EnhancementSplanchnic CirculationImaging, Three-DimensionalCentral Venous PressureOrgan SizeWater-Electrolyte BalanceIndicator Dilution TechniquesForced Expiratory VolumeAcetazolamideLiver CirculationReference ValuesDiuresisPostureTechnetiumColoring AgentsBrain IschemiaCarbon MonoxideSupine PositionSaline Solution, HypertonicBody WaterPressureEcho-Planar ImagingBlood Gas AnalysisCapillariesValsalva ManeuverPressoreceptorsPlethysmography, ImpedanceShockLungVeinsAlgorithmsCapillary PermeabilityHyperventilationResuscitationVasopressinsOxyhemoglobinsMicrovesselsForeheadColloidsProspective StudiesGliomaSodium ChlorideAnalysis of Variance