Blood CirculationVeinsArteriesJugular VeinsFemoral VeinRegional Blood FlowPulmonary ArteryHemodynamicsDogsBlood PressureExtracorporeal CirculationPulmonary CirculationCollateral CirculationEnterohepatic CirculationCoronary CirculationCerebrovascular CirculationPlacental CirculationSplanchnic CirculationBlood Circulation TimeLiver CirculationTime FactorsBlood Flow VelocityVascular ResistancePregnancyCross CirculationTreatment OutcomeAssisted CirculationHeart ArrestCardiopulmonary ResuscitationRenal CirculationLiverPlacentaMetabolic Clearance RateMaternal-Fetal ExchangeTissue DistributionInjections, IntravenousRetrospective StudiesVasodilationVertebrobasilar InsufficiencyLaser-Doppler FlowmetryMicrocirculationVasoconstrictionHalf-LifeLungFetusCerebral ArteriesFontan ProcedureOxygenCardiac OutputVasodilator AgentsPerfusionFollow-Up StudiesProspective StudiesDisease Models, AnimalPortal SystemSheepRabbitsSwineNitric OxideCerebral AngiographyBronchial ArteriesRats, Sprague-DawleyPolyethylene GlycolsInfant, NewbornRisk FactorsBlood VesselsCoronary VesselsEndothelium, VascularErythrocytesPulsatile FlowHeart RateAnoxiaMice, Inbred C57BLDose-Response Relationship, DrugDrug Carriers