重医大临床麻醉学教案10椎管内麻醉

PAGEPAGE13授课教案课程名称临床麻醉学年级授课专业麻醉学系教师职称授课方式大课学时4题目章节第十章椎管内麻醉教材名称根据《临床麻醉学》椎管内麻醉章节改编为英文作者房秀生，刘新伟出版社版次第一版教学目的要求蛛网膜下腔阻滞：熟悉腰麻的作用机理及其对生理的影响。掌握腰麻的适应证，禁忌证与并发证。熟悉腰麻的平面调节和用药基本方法。了解穿刺要点。硬膜外阻滞。熟悉硬膜外阻滞的作用机理及其对生理的影响，掌握硬膜外麻醉的适应证，禁忌证，平面调节和麻醉管理。理解其穿刺要点，注药方法，掌握硬膜外麻醉的并发证。教学难点椎管的解剖，穿刺层次，注药部位。椎管内麻醉对生理的影响。影响腰麻平面的因素及平面的调节。术后头痛的原因与处理。硬膜外麻醉注药原则全脊椎麻醉的产生与预防，处理。教学重点椎管的解剖，穿刺层次，注药部位。腰麻与硬膜外麻醉对生理影响。腰麻与硬膜外麻醉的适应证与并发症。腰麻与硬膜外麻醉的区别外语要求掌握椎管内麻醉章的英文关键词，能基本听懂全英文讲课，intrathecalanesthesia;epiduralanesthesia;spinalanesthesia;cerebrospinalfluid(CSF).教学方法手段讲授及多媒体教学。参考资料《Clinicalanesthesia》ByG.E.Morgan.《Textbookofanesthesia》ByA.R.Aitkenhead教研室意同意教学组长：教研室主任：20年月日教学内容辅助手段时间分配IntrathecalAnesthesiaIntrathecalanesthesia.Intrathecalanesthesiaresultinsympatheticblock,sensoryanalgesia,andmotorblock(dependingondose,concentration,orvolumeoflocalanesthetic)bylocalanestheticisinjectedintosubarachnoidspace(spinalanesthesia)ortheepiduralspace(epiduralanesthesia)andbathesthenerverootsinthesubarachnoidspaceorepiduralspace,respectivelyIntrathecalblockisdividedintotwoclassesSubarachnoidblock(spinalblock):Localanestheticisinjectedinto subarachnoidspace.Epiduralblock:Localanestheticisinjected intotheepiduralspace.AnatomyVertebralcolumn7cervical(C),12thoracic(T),5lumbar(L),5sacral(S)fusedasthe sacrum,4smallcoccygealvertebra(Co)thatformthecoccyxVERTEBRAThevertebralarchenclosesthevertebralforamen,eachvertebralarchhastwoparts,thatispedicle(root)andlamina.Pedicleshavelargenotchesontheirinferiorsurfaceandsmallernotchesontheirsuperiorsurface.Notchesfromadjacentvertebraeformintervertebralforamina,throughwhichnerverootsexitthespinalcolumn.Sacrum&Coccyx:Thesacralhiatusleadsintothesacralcanal,theinferiorendofthevertebralcanal.LigamentumofvertebralcolumnSupraspinousligamentInterspinousligamentLigamentumflavum(theyollowligament)SpinalcordThespinalcordextendsfromtheforamenmagnumtothelevelofL1inadults.Theanteriorandposteriornerverootsateachspinalleveljoinoneanother.Caudaequina(horse’stail).Spinalmeninges7spinalcord8spinalduramater9arachnoidmater10spinalpiamaterSpinalspaceEpiduralspaceSubduralspaceSubarachnoidspaceSpinalnervesdermatomicdistributionT2manubriumofsternumT4nipplT6xiphoidprocessT8betweenT6&T10T10navelT12pubicsymphysisPhysiologicEffectsofIntrathecalAnesthesiaNerveblockadesequenceSympathetic--sensory-motor–sheathednerve.DifferentialnerveblockadelevelSympatheticblockadethatmaybetwosegmentslevelhigherthanthesensory block,whichinturnistwosegmentshigherthanthemotorblockade.Respiratorysystem1.Lowspinalblockorlowepiduralblockhasnoeffectontherespiratorysystem.2.Motorblockadeextendingtotherootsof thephrenicnerves(C3-5)causesapnea.3. Highthoraciclevelblockadecancause lossofintercostalmuscleactivity,there isamarkeddecreaseinvitalcapacity.Cardiovascularsystem1.Decreasebloodpressure.2.Reductionincardiacoutputandcardiac contractility.3.Bradycardia.(blockT1–T4).GastrointestinalsystemIncreaseintestinalcontraction.2.Nausea,retchingorvomiting:SpinalAnesthesia(spinalblockorsubarachnoidblock,SAB)SABisatypeofregionalanesthesia,whichisachievedbyinjectingalocalanestheticintothelumbarsubarachnoidspace.ThetermforSABlevelBlocklevelhigherT4ishighlevelSABBlocklevellowerT10islowlevelSABBlockregiononlycovertheperineum &buttockissaddleblockBlockonlyoccurinunilaterallowerextremityisunilateralblock.LocalanestheticsforSABSolutionbaricity:(ThespecificgravityofCSFis1.003-1.009at37℃.)1.HyperbaricsolutionAdditionofglucose5%or10%toalocal anestheticsolutionproducesasolution withspecificgravityof1.024orgreater, this solutionisheavierthanCSF.AhypobaricsolutionLighterthanCSF,itcanbemadebythepowderanestheticplusofsterilewaterorthepureanestheticsolution.Anisobaric(plain)solution;Anestheticagents are mixedwithCSF.Localanestheticsolution:(hyperbaricwithepinephrine)Procaine5%solution+5%glucose. Dosage:100-150mg.Duration:45-90minTetracaine1%solution1ml+10%glucose1ml+3% efedrina1ml.(1+1+1solution). Dosage:10-12mg.Duration:120-240minBupivacaine0.75%solution+5-10%glucose Dosage:10-15mg.Duration:100-150minVasoconstrictorsEpinephrine&phenylephrineBothagentsappeartodecreasetheuptake and clearanceoflocalanesthetics fromCSF.Additionofvasoconstrictorsinlocal anestheticsolutioncanprolongthe durationofspinal anesthesia.Dosage:Epinephrine(0.1-0.2mg).Assessingblockadelevel:Thesensorylevelofblockadecanbe assessedwithpinprickorice,the levelof sympathectomyisassessed bymeasuring skintemperature.Thecompleteblockofmotornerves is manifestedinabilitytomovethe legsorfoot.Factorsaffectingspreadofhyperbaric1.spinalsolution2.Patient’sposition“saddleblock” keepingthepatient sittingfor 3-5minafterinjectionof1-2mlof hyperbaricsolution.“unilateralblock”keepingthepatienton lateralposition.Drugdosage&solutionvolume.3.Speedofinjection.Therateofinjectionis1ml/5sec.4.Lumberpuncturesite.5.Needlebeveldirection.SABlevelmanagement(Hyperbaricsolution)ComplicationsofSABHypotensionReasons:vesselsdilatation;increasedbloodpooling; bloodflow decreasedreturntoheart.Cardiac contractilitydecreased.Augmentedby:HypovolemiaChangesinpositionBradycardiaTreatmentPrevention:Useofcrystalloidorcolloid fluidsIV10-20ml/kgforvolume loadingpre-lumberpuncture.Increasefluidadministration.Maskoxygeninhale.Drug:Ephedrine10-15mgIV.BradycardiaReasons:SpinalblocklevelhigherthanT4,whichmay blockthecardiac sympathetic accelerator fibers(T1- T4),thenbradycardia mayoccur.SABdoesnotblockthevagalnerve. Unopposed vagaltoneincreasedisanother reason for bradycardia.TreatmentAtropine0.25–0.5mgiv.Ephedrine15-30mgiv.NauseaandvomitingReasonsincreasedvagaltonehypotensionOperationexplorationHypoxemiaTreatment:CheckBP&HRAtropine0.25-0.5mg.iv.Ephedrine15mg–30mg.iv.Maskoxygeninhale4.Headache(post–duralpunctureheadache,PDPH)Theincidencerateisabout20-30%.Headachemayoccurafterduralpuncture,presumablysecondarytothetearintheduraandthatresultfromdecreasedintracranialpressureasCSFleakfromtheduraldefect,whichmaycausetractiononthemeningesandcranialnerves.ClinicalcharacteristicsTheonsettimein12-72hours.persistforupto1-6weeks.Theheadacheisaggravatedbysittingor standing.Relievedorlessenedbylyingdownflat.Travenousororalfluidadministration.epiduralbloodpatchtreatmentasalinebolusepiduralspaceinjectionsedative&analgesicagentUrinaryretentionReasonsBlockofS2-S4rootfibersdecreases urinarybladdertoneandinhibitsthe voidingreflex.Associatedwiththesurgicalprocedure.Urinaryretentionisusuallytemporary.Persistentbladderdysfunctionmaybea seriousneuralinjury.Treatment:aurethralcatheterinsertedNeurologiccomplicationsCaudaequinasyndromeMeningitisArachnoiditisCranialnervepalsyIndications&ContraindicationsIndicationslowerabdomenoperation.perineumoperation.lowerlimbsoperation.Contraindications

Infectionatthesiteofpuncture.Bleedingdiathesisorcoagulopathy.Severehypovolemia.Severecardiovasculardiseases.Severespinaldeformity.Preexistingneurologicdiseases.IntracranialhighpressureEpiduralAnesthesiaConceptEpiduralanesthesiaisachievedbyinjectingalocalanestheticintotheepiduralspace,whichblocksthespinalnerveroots,producingregionalanesthesia.Epiduralblockmethodsasingle-shotinjectivetechniques.acontinuousinfusion&intermittent bolustechniques. “Acatheterinserttotheepiduralspaceforcontinuousinfusionorintermittentbolusinjection.”Epiduralanestheticagents1.Lidocaineshort–tointermediate-actingagent.concentrationof1.5-2.0%withadrenaline 1:200,000.anesthesiaduration90-150min.totaldosagelimited400mginadult.Bupivacainelong-actinglocalanesthetic.usedin0.5%or0.75%withadrenalin 1:200,000 .onsettimeis10-15min.durationisabout200-260min.dosagelimited150mginadult.3.Ropivacainenewamidelocalanestheticwithaless cardiac toxicitythanbupivacaineslowonsettimeandlonganesthesia duration.use0.5%or0.75%with1:200,000 or without adrenalin.Dosagelimited150-200mginadult.AdministrationoflocalanestheticThequantityoflocalanestheticneedforepiduralanesthesiaisrelativelylargercomparedwithspinalanesthesia.Significanttoxicitycanoccurifthisamountofanestheticisinjectedsubarachnoidspaceorintravascular.Safeguardsaretheepiduraltestdoseandincrementaldosing(ormaindose).TestdoseAim:todetectwhethersubarachnoidinjectiontodetectwhetherintravascularinjectionMethod:3-4mlof2%lidocainewith1:200,000epinephrine(5ug/ml)isinjectedtoepiduralspace.ifinjectedintosubarachnoidspace,thatwillproducespinalanesthesiarapidly.The15ug-20ugofepinephrine,ifinjectedintravascularly,anoticeableincreaseinheartrateproduced.IncrementaldoseIncrementaldoseisaveryeffectivemethodofavoidingseriouscomplication.After5minoftestdosegiven,thereisnosystemtoxicity&nosignsofspinalanesthesiaoccursthentheincrementaldosecanbeinjectedintoepiduralspace.FactorsaffectingblockinglevelofanesthesiaVolume: inadults,1-2mloflocalanestheticpersegmenttobeblockedisagenerallyacceptedguideline. Forexample,toachieveaT4sensorylevelfromanL4–L5injectionwouldrequireabout12-24ml.Age: Thedoserequiredtoachievethesame levelofanesthesiadecreaseswithage.Thisisprobablyaresultofage-relateddecreasesinthesizeorcomplianceoftheepiduralspace.Sotheolderpatientsrequireslesslocalanesthetic.3.Height:Thepatientheightaffectstheextentofcephaladspread.Thustheshorterpatientsmayrequiresonly1mloflocalanestheticpersegmenttobeblocked,whilethetallerpatientgenerallyrequires2mlpersegment.Pregnancy:Requireslessvolumeofanesthetic.Becausetheepiduralspacevenousdilatationanditispressureincreasedbypregnancy,itisaugmentedtheanestheticspreadingwider.PuncturesiteHighlevelepiduralblock(C5-T6).Middlelevelepiduralblock(T6-T12).Lowlevelepiduralblock(L1-).Caudalblock.FailedepiduralblocksmisplacedinjectionunilateralblocksegmentalsparingvisceralpainComplicationsIntraoperativecomplications1.DuraltapTheepiduralneedlepuncturetheduramater &subarachnoidmaterandentersinto subarachnoid space.Itcanbe recognized byfree flowofCSFdripsfromthe needle.Anepiduralcathetermightpuncturethe dural.Totalspinalanesthesia(TSA)Allofthenerveroots&brainsteambeblockedbylargevolumeoflocalanestheticinjectedintosubarachnoidspace.Signsandsymptoms:severehypotension.severebradycardia.Apnea.lossofconsciousness.cardiacarrest.TreatmentofTSASteps:A. Keepingtheairwaypatency,maintaining adequateventilationandgivingoxygen.B.Supportingcirculation:Infusionofintravenousfluidsquickly.UsevasopressorsbyIV.C.Ifcardiacarrestoccurs,CPRmustbeimmediatelyperformed.PreventionofTSAstrictlyusingthetestdoseoflocal anesthetic.aspirationthecatheterbefore injection .carefullyobservingpatientafterinjected localanesthetic..ToxicreactionReasonsintravascularinjection.absorptionofexcessiveamountsofanesthetic.Clinicalcharacteristics numbnessortinglingoftongue.tinnitus,lingualsensations&lightheaded.consciousnesslost.convulsion.Preventionaspiratingtheneedleorcatheter.usingtestdose.observingearlysignsoftoxicity.Managementoxygeninhale.patencyairway.sedative&anti-convulsionagents.keepingcirculationstable.4.HypotensionManagementcrystalloidorcolloidsolution.IV.Infusionephedrine15-30mgIV.atropine0.25-0.5mgIV.Oxygeninhale.NauseaorvomitingReasonshypotensionvisceralmanipulationhypoxemiaManagementincreasefluidtransfusioninhaleoxygendrugusage:atropine,efedrina,antiemetics. RespiratorydepressionReasonshighlevelofepiduralanesthesia.ClinicalsignsSO2%decreased,tidalvolumedecreased,orapnea.Managementavoidhighblocklevel.decreaseanestheticdrugconcentration.oxygeninhale&respiratorysupport.PostoperativecomplicationsHeadacheReasonfollowingduratap.Managementlyinginbed.liquidinfusion.sedative&analgesiaagents.epiduralbloodpatch.NeurologicinjuryReasonsPuncturetraumatospinalroot,nervefibersorspinalcord.nerveinjuryresultfromthedirect effectoflocalanesthetics.ManagementPrevention.Consulatationneurologicphysician

3.EpiduralhematomaReasonabnormalcoagulationor bleeding disorder. puncturetrauma.Manag