DexmedetomidineMedetomidineAdrenergic alpha-2 Receptor AgonistsAdrenergic alpha-AgonistsHypnotics and SedativesImidazolesConscious SedationReceptors, Adrenergic, alpha-2Analgesics, Non-NarcoticAdjuvants, AnesthesiaMidazolamShiveringClonidineAdrenergic alpha-AntagonistsDeep SedationIdazoxanAirway ExtubationImidazoline ReceptorsPreanesthetic MedicationAdrenergic alpha-2 Receptor AntagonistsHemodynamicsFentanylInfusions, IntravenousConsciousness MonitorsDioxanesPropofolPsychomotor AgitationDose-Response Relationship, DrugAlfentanilAdjuvants, PharmaceuticInjections, SpinalDouble-Blind MethodAnalgesicsAnesthesia Recovery PeriodSympatholyticsHeart RateLocus CoeruleusDeliriumPremedicationAnesthetics, InhalationAnalgesia