外科学教学课件：Acute-Pain-Management

AcutePainManagementObjectives/DiscussionTopicsPathophysiologicalconsequencesofacutepainAppropriateassessmentofacutepainConceptofmulti-modalanalgesiaIndicationsandsideeffectsofanalgesicsHowtorationallyprescribeopioidssideeffectsandcomplicationsofopioidsSpecialpopulationsieelderly,opioidtolerantNeuraxial/regionalanalgesiasideeffectsandcomplicationsofneuraxialanalgesiainteractionofvariousanticoagulantmedicationsandneuraxialanalgesia疼痛形成的过程疼痛形成的神经传导基本过程可分为4个阶梯伤害感受器的痛觉传感(transduction)一级传入纤维、脊髓背角、脊髓一丘脑束等上行束的痛觉传递(transmission)皮层和边缘系统的痛觉整合(interpretation)下行控制和神经介质的痛觉调控(modulation)Transduction痛觉传感皮肤、躯体(肌肉、肌腱、关节、骨膜和骨骼)、小血管和毛细血管旁结缔组织和内脏神经末梢是痛觉的外周伤害感受器。体表刺激通过皮肤的温度、机械感受器传递疼痛。内脏伤害感受器感受空腔脏器的收缩、膨胀或局部缺血刺激，运动系统的疼痛通过躯体伤害感受器感知。Transmission（1）痛觉传入神经纤维：传导痛觉信号的一级传入神经轴突是有髓鞘的Aδ纤维和无髓鞘的C纤维，其神经胞体位于脊髓背根神经节。（2）疼痛信号在脊髓中的传递：脊髓是疼痛信号处理的初级中枢。伤害性刺激的信号由一级传入纤维传入脊髓背角，经过初步整合后，一方面作用于腹角运动细胞，引起局部的防御性反射，另一方面则继续向上传递。（3）疼痛信号由脊髓传递入脑：身体不同部位疼痛信号在脊髓传导的上行通路分为：躯干和四肢的痛觉通路，头面部的痛觉通路和内脏痛觉通路。（4）参与疼痛信号传导的受体：在传导通路中有许多受体参与疼痛信号的传导。其中阿片受体（μ-阿片受体、δ-阿片受体和κ-阿片受体）是疼痛信号传递及镇痛过程中最重要的受体。Interpretation皮层和边缘系统的痛觉整合脊髓丘脑束进入丘脑后形成二级神经元，发出纤维：①至白质的躯体感觉部位；②与网状结构和丘脑核相连，因此在感到疼痛时呼吸和循环会受到影响；③延伸至边缘系统和扣带回，导致疼痛的情绪变化；④与垂体相连，引起内分泌改变；⑤与上行网状激活系统相连，影响注意力和警觉力。丘脑既是各种躯体感觉信息进入大脑皮质之前最重要的传递中枢，也是重要的整合中枢。Modulation下行痛觉调控（1）脊髓水平的调控：在脊髓背角胶质区存在大量参与背角痛觉信号调节的内源性阿片肽(脑啡肽和强啡肽)、中间神经元及各类阿片受体。（2）脑水平的调控：内源性痛觉调制的重要结构位于脑部的下行镇痛系统。中脑导水管周围灰质(PAG)是内源性痛觉调制下行镇痛系统中起核心作用的重要结构。（3）下行痛觉易化系统：通过降低痛阈值(敏化)提高机体对伤害性刺激的反应能力，也使患者表现出对疼痛高度敏感。（4）下行痛觉调控系统的调节因子：阿片肽是下行痛觉调控系统中最重要的激活及调节因子。人体自身镇痛潜能在较大程度上受内源性阿片肽释放及其参与的下行痛觉调控的影响。Cardiovascular:tachycardia,hypertension,increasedSVR,increasedcardiacworkPulmonary:

hypoxia,hypercarbia,atelectasis;decreasedcough,VC,FRC;ventilationperfusionmismatchGastrointestinal:nausea,vomiting,ileus,NPORenal:oliguria,urinaryretentionPathophysiologicalconsequencesofacutepain()ExtremitiesEndocrineCentralnervoussystemImmunologicskeletalmusclepain,limitedmobility,thromboembolismvagalinhibition;increasedadrenergicactivity,metabolism,anxiety,fear,sedation,fatigueimpairmentPathophysiologicalconsequencesofacutepain(I)术后疼痛危害严重疼痛不仅给病人带来精神和肉体痛苦，干扰睡眠，影响情绪和日常活动，还可能带来一系列影响内分泌反应心、肺功能影响长期不良影响对胃肠道的影响促血栓形成减低胃肠道蠕动，增加恶心、呕吐、麻痹性肠梗阻的发生机会，延长住院时间，增加医疗费用严重急性疼痛治疗不充分时发展成慢性疼痛的危险因素静脉瘀滞，术后活动减少，增加深静脉栓塞甚至肺栓塞的危险心率加快、心脏做功增加和氧消耗加大，血压也可能增高，甚至可能导致脑卒中和心肌缺血水钠潴留，功能性细胞外液减低、液体向细胞内转移术后疼痛危害1GoalToprovidepatientswithalevelofpaincontrolthatallowsthemtoactivelyparticipateinrecoveryThislevelwillbeindividualtoeachpatientTominimizenauseaandvomitingTominimizeothersideeffectsofanalgesicsSedationIleusWeaknessHypotension良好的镇痛有诸多获益患者层面缓解患者紧张情绪有利于术后功能锻炼改善睡眠增强免疫力促进功能恢复良好镇痛获益1,2医护层面明显改善手术结果提高患者满意度缩短住院时间为患者提供更好且更有效的医疗服务1.李东文,等.实用医学杂志.2007;(23)18:2814-2815.2.江志伟,等.中国实用外科杂志.2007;27(2):131-33.Whyallthefuss?PainisamiserableexperiencePainincreasessympatheticoutputIncreasesmyocardialoxygendemandIncreasesBP,HRPainlimitsmobilityIncreasesriskforDVT/PEIncreasesriskforpneumonia,atelectasissecondarytosplintingAssessmentIntensityLocationOnsetDurationRadiationExacerbationAlleviationNumericPainIntensity(NPS)：0：nopain；1-3：mildpain；4-6：Moderatepain；7-10：WorstpossiblepainAssessmentVisualAnalogueScale

AssessmentWong-Baker

faceAssessmentHowdowedoit?Multimodalanalgesia:Severalanalgesicswithdifferentmechanismsofaction,eachworkingatdifferentsitesinthenervoussystem

AcetaminophenNon-steroidalanti-inflammatorydrugs(NSAIDs)OpioidsAnticonvulsantsAntidepressantsLocalanaestheticsNMDAAntagonistsNon-pharmacologicmethods

OPIOIDS

EfficacyislimitedbySide-EffectsTheharderwe“push”withsinglemodeanalgesia,thegreaterthedegreeofside-effects

AnalgesiaSide-effectsMultimodalAnalgesiaLowerdosesofeachdrugcanbeusedthereforeminimizingsideeffectsWiththemultimodalanalgesicapproachthereisadditiveorevensynergisticanalgesia,whiletheside-effectsprofilesaredifferentandofsmalldegree(Pasero&Stannard,2012).

AnalgesiaSide-effects多模式镇痛联合使用作用机制不同的镇痛药物或镇痛方法，由于每种药物的剂量减小，副作用相应降低，镇痛作用相加或协同，从而达到最大的效应/副作用比临床上常在下列类型药物之间进行组合：对乙酰氨基酚、NSAIDs、曲马多和阿片类阿片类或曲马多与对乙酰氨基酚联合对乙酰氨基酚的每日量1.5~2.0g，可节俭阿片类药物20%~40%对乙酰氨基酚与NSAIDs联合两者各使用常规剂量的1/2，可发挥镇痛协同作用阿片类或曲马多与NSAIDs联合使用常规剂量的NSAIDs可节俭阿片类药物20%~50%，尤其是可能达到患者清醒状态下的良好镇痛。在脑脊液中浓度较高的COX-2抑制剂(如帕瑞昔布)术前开始使用具有抗炎、抑制中枢和外周敏化作用，并可降低术后疼痛转化成慢性疼痛的发生率阿片类与局麻药联合用于PCEA(阿片受体激动-拮抗剂布托啡诺亦可单独或与NSAIDs、对乙酰氨基酚、曲马多等合用于PCIA，与局麻药合用于PCEA)氯胺酮、可乐定等也可与阿片类药物联合应用，偶尔可使用三种作用机制不同的药物实施多靶点镇痛镇痛药物的联合应用中华医学会麻醉学分会.成人手术后疼痛处理专家共识.临床麻醉学杂志.2010;26(3)190-196.术后镇痛的常用方法全身给药局部给药病人自控镇痛口服给药肌肉注射给药静脉注射给药局部浸润外周神经阻滞硬脊膜外腔给药PCIA

PCEA

PCSAPCNA多模式镇痛镇痛药物的联合应用镇痛方法的联合应用中华医学会麻醉学分会.成人手术后疼痛处理专家共识.临床麻醉学杂志.2010;26(3)190-196.SystemicAnalgesiaOpioidsPotentanalgesicsDrugofchoiceformoderatetoseverepainUnfortunately,theyareoftentheonlydrugorderedSideeffects:Opioids10foldvariabilitybetweenpatientsAllopioidshavesamesideeffectsbutefficacy:sideeffectratioisdifferentforeveryoneStickwithwhatworksandkeepitsimpleAlwaysbymouthifpossibleAvoidpro-drugsie.codeineAvoidcombopreparationsEquianalgesiaOpioidPOParenteral(IV/SC)Morphine10mg5mgCodeine~60-100mg(4-foldvariability)N/AHydromorphone2mg1mgOxycodone5mgN/ANALOXONE(Narcan)MuopioidantagonistDilute1mLofnaloxone0.4mg/mL(ie.onevial)with9mLofNSforatotalof10mLofsolutionandafinalconcentrationof0.04mg/mLAdminister0.04mgatatimeuntilreversalofrespiratorydepressionhasbeenachieved,ie.whenthey’resittingupawakeandtalkingtoyou!NALOXONE(Narcan)REMEMBER:thehalf-lifeofnaloxoneisonly30minutes,whilethehalf-lifeofopioidis2-3hrsoyoumayhavetorepeatdosingORplaceptonnaloxoneinfusionuntilallopioidhasbeenmetabolizedtopreventfurtherrespiratorydepressionElderlyPatientPronouncedeffecttherefore,lowerdosesCognitivedysfunctionisamajorissueOrgandysfunction/insufficiencyaffectsmetabolismInteractionwithothermedications,increasedincidenceofpolypharmacyAddictionPrimary,chronic,neurobiologicdisease,withgenetic,psychosocial,andenvironmentalfactorsinfluencingitsdevelopmentandmanifestations.Characterizedbybehaviorsthatincludeoneormoreofthefollowing:impairedcontroloverdrugusecompulsiveusecontinuedusedespiteharmcravingDefinitionsRelatedtotheUseofOpioidsfortheTreatmentofPain.AmericanAcademyofPainMedicine;AmericanPainSociety;AmericanSocietyofAddictionMedicine.2001.PhysicalDependenceStateofadaptationthatismanifestedbyadrugclass-specificwithdrawalsyndromethatcanbeproducedbyabruptcessation,rapiddosereduction,decreasingbloodlevelofthedrug,and/oradministrationofanantagonistToleranceThebody'sphysicaladaptationtoadrug:GreateramountsofthedrugarerequiredovertimetoachievetheinitialeffectasthebodyadaptstotheintakePseudoAddictionTermusedtodescribepatientbehaviorsthatmayoccurwhenpainisundertreated

Maybecomefocusedonobtainingmedications,"clockwatch,"seeminappropriately"drugseeking."Illicitdruguseanddeceptioncanoccurinthepatient'seffortstoobtainreliefDistinguishedfromtrueaddictioninthatthebehaviorsresolvewhenpainiseffectivelytreated.NSAIDSWorkatsiteoftissueinjurytopreventtheformationofthenociceptivemediatorsProstaglandinsCandecreaseopioiduse~30%thereforedecreasingopioid-relatedsideeffectsMinorsurgeriescanuseNSAIDsinsteadofopioidstocompletelyeliminateopioid-associatedsideeffectsSideeffects:NSAIDSNewerNSAIDSselectively(primarily)inhibitcyclooxygenase-2(COX-2)whichisinducedbysurgicaltraumawithminimaleffectonCOX-1whichisresponsibleforGIandplateletsideeffectsCelecoxib(Celebrex)NeuraxialTechniques

WhoGetsThem?Patientfactors:Lowpaintolerance,opioidtoleranceSleepapneaNarcolepsyObesityCOPDCardiacdiseaseElderly–thoseatriskforpost-operativecognitivedysfunction…….EpiduralInfusionsUsedformajorsurgeryie.oncologicTAHBSO,thoracotomyIdeallyplacedpre-operativelyandusedincombinationwithaGAforsurgeryandcontinued~2daysUsuallypatientistoleratingdietandambulationtochairwhenepiduralisD/CIdealEpiduralInfusionsWhenplacedattheleveloftheincisionandwithaconstantinfusionofLAandopioid:Minimalornopainatall,particularlywithmovementNomotorblockCanambulateSpeedierreturnofbowelfunctionWithmoreLAandlessopioid–Cochranereview2003LessnauseaLesssedationLessdeleriumDonotrequiresupplementalIVopioidsandassociatedsideeffectsLesspulmonarycomplicationsQuickerextubation,betteroxygensaturation,lesspneumoniaSideEffectsofEpiduralInfusionsHypotensionLAcausesasympathectomywhichleadstovasodilatationMildvolumedepletion,whichcannormallybecompensatedforwithvasoconstriction,willbeunmaskedwithanepiduralPtsrequireadequatevolumestatuswithanepiduralSideEffectsHypotensionPtswillinitiallyc/odizzyness,lightheadednessandnauseawhensittinguporstandingCandocumentorthostatichypotensionWillthenprogresstosupinehypotensionifnotcorrectedMajorproblemwhen3rdspacingstilloccurring,minimalIVfluidsinfusingandptNPOSideEffectsLegweaknessornumbnessCanoccurifcatheteristoolow(lowthoracicorlumbar)orifitisone-sidedInhibitsambulationanddistressingtoptthereforemustbefixedInfusioncanbeadjustedorcatheterpulledbackMustbeaddressedasthisisthefirstsignofepiduralhematomaleadingtopermanentparalysisComplicationsPostduralpunctureheadache1:100OnlyifduraisunintentionallypuncturedMorelikelyinyoungerpeopleInfectionSomereportsofepiduralabscessashighas1:1900UsuallyjustsuperficialskininfectionsIncreasedriskinimmunosuppressedComplicationsEpiduralhematomaMostfearedcomplicationIncidenceof1:180000–1:220000Increasedwithheparin,age,gender,ASA,NSAIDs,traumaticplacement,spinalstenosisLegweakness,numbnessandbladder/boweldisturbancearefirstsignsIfnotevacuatedwithin8-12hours,usuallyleadstopermanentparalysisComplicationsEpiduralHematomaRisksAbnormalcoagulationElderlyFemaleDebilitatedpatientsTraumaticinsertionUnknownspinalpathologyIdealPatientCareSurgeons,APMS,nursingallworkingforsamegoalPre-operativeoptimizationIntra-operativecarePost-operativeAmbulation,pain,bowels,voiding

ImprovedpatientrecoveryAddiction–proposedmechanismsIncentivesensitizationCasualusesensitizesrewardsystemhighmotivationtorepeatrewardingbehaviourforpleasurableexperienceHedonicallostasisChronicexposureandproductionofstressfactorsandnegativeemotionalstate,withdrawalandanxietyUsetoavoidnegative-affectstateMesocorticolimbicdopaminesystemWand,G.(2010).Theinfluenceofstressonthetransitionfromdrugusetoaddiction.Nationalinstituteonalcoholabuseandalcoholism:NationalInstituteofHealth.Addiction–proposedmechanismsPositiverewardRewardsystemresponds–corticotropicreleasingfactorsandstressfact