Acute Chest SyndromeAnemia, Sickle CellChest PainEmbolism, FatHemoglobin SC DiseaseAntisickling AgentsSyndromeLung DiseasesSickle Cell TraitAcute DiseaseHydroxyureaHemoglobin, SicklePainBlood TransfusionFetal HemoglobinMyocardial InfarctionInfarctionRespiratory InsufficiencyPulmonary EmbolismHemolysisFeverLeukocytosisCerebral InfarctionRetrospective StudiesCohort StudiesTriageElectrocardiographyAcute Coronary SyndromeEmergency Service, HospitalCoronary AngiographyTomography, X-Ray ComputedProspective StudiesTroponin TAngina, UnstableThoraxAngina PectorisTroponin ITime FactorsPredictive Value of Tests