AnalgesiaAnalgesia, EpiduralAnalgesia, ObstetricalAnalgesics, OpioidAnalgesia, Patient-ControlledFentanylPain, PostoperativeAnesthetics, IntravenousSufentanilMorphinePain MeasurementAnesthesia, IntravenousPropofolMeperidineAnesthetics, CombinedAnesthetics, LocalBupivacaineMuscle RigidityNitrous OxideAdjuvants, AnesthesiaAnalgesicsAcupuncture AnalgesiaPainAnesthesia, GeneralDouble-Blind MethodInjections, SpinalAnesthesia, EpiduralHypnotics and SedativesAnesthesia Recovery PeriodLabor PainPiperidinesNaloxoneMidazolamShiveringInfusion PumpsConscious SedationNerve BlockNefopamRespirationReceptors, Opioid, muMedetomidineDrug InteractionsClonidineLabor, ObstetricAnesthesia, ObstetricalDose-Response Relationship, DrugKetamineInfusions, IntravenousLidocaineAmidesAnesthesia, InhalationAnesthesia, SpinalTramadolCross-Over StudiesAnesthetics, DissociativeElectroacupunctureAbdomenTroleandomycinAnalgesics, Non-NarcoticCatalepsyMiosisDrug Therapy, Computer-AssistedDeep SedationAmbulatory Surgical ProceduresAnesthesiaDermatologic Surgical ProceduresIntraoperative PeriodCesarean SectionPostoperative Nausea and VomitingConsciousnessPain ThresholdInterpleural AnalgesiaAlfentanilPlacebo EffectInjections, IntravenousDrug TolerancePreanesthetic MedicationProspective StudiesIntubation, IntratrachealAdrenergic alpha-AgonistsHemodynamicsElectroencephalographyKetorolacHysterectomyLabor Stage, FirstDrug Administration ScheduleHydromorphoneDebrisoquinMethohexitalNauseaNeuromuscular Nondepolarizing AgentsHyperalgesiaPain ManagementHalf-LifeAnesthesia, CaudalCytochrome P-450 CYP3AAnesthesia and AnalgesiaNarcoticsAnestheticsSingle-Blind Method