Acute Chest SyndromeAnemia, Sickle CellChest PainEmbolism, FatHemoglobin SC DiseaseAntisickling AgentsSyndromeLung DiseasesStrokeSickle Cell TraitAcute DiseaseHydroxyureaHemoglobin, SicklePainBlood TransfusionFetal HemoglobinRespiratory InsufficiencyPulmonary EmbolismFeverHemolysisLeukocytosisRetrospective StudiesCohort StudiesTriageEmergency Service, HospitalAcute Coronary SyndromeTomography, X-Ray ComputedProspective StudiesThoraxBrain Ischemia