重醫(yī)大臨床麻醉學(xué)課件10椎管內(nèi)麻醉

1IntrathecalAnesthesia

2Intrathecalanesthesia:Intrathecalanesthesiaresultinsympatheticblock,sensoryanalgesia,andmotorblock(dependingondose,concentration,orvolumeoflocalanesthetic)bylocalanestheticwhichisinjectedintosubarachnoidspace(spinalanesthesia)ortheepiduralspace(epiduralanesthesia)andbathesthenerverootsinthesubarachnoidspaceorepiduralspace,respectively

3Intrathecalblockisdividedintotwoclasses

Subarachnoidblock(spinalblock):Localanestheticisinjectedinto subarachnoidspace.Epiduralblock:Localanestheticis injected intoepiduralspace.

4AnatomyVertebralcolumn7cervical

(C),12thoracic(T),5lumbar

(L),5sacral

(S)fusedasthe sacrum,4smallcoccygealvertebra(Co)thatformthecoccyx.5

VERTEBRA6Thevertebralarchenclosesthevertebralforamen,eachvertebralarchhastwoparts,thatispedicle(root)andlamina.Pedicleshavelargenotchesontheirinferiorsurfaceandsmallernotchesontheirsuperiorsurface.7Theinferiorandsuperiornotchesfromadjacentvertebraeformintervertebralforamina,throughwhichnerverootsexitthespinalcolumn.

8Sacrum&Coccyx:Thesacralhiatusleadsintothesacralcanal,theinferiorendofthevertebralcanal.9Ligamentumofvertebral column

SupraspinousligamentInterspinousligamentLigamentumflavum(theyollowligament)10Spinalmeninges7-----spinalcord8-----spinalduramater9-----arachnoidmater10---spinalpiamater11SpinalspaceEpiduralspaceSubduralspaceSubarachnoidspace12SpinalcordThespinalcordextendsfromtheforamenmagnumtothelevelofL1inadults.Butinchildren,thespinalcordendsatL2~L3andmovesupastheygrowtholder.

Theanteriorandposteriornerverootsateachspinalleveljoinoneanother.Caudaequina(horse’stail).13

Spinalnerves

dermatomic distribution

T2-----manubriumof sternumT4----nipplT6----xiphoidprocessT8----betweenT6&T10T10---navelT12---pubicsymphysis14PhysiologicEffectsofIntrathecalAnesthesia15Nerveblockadesequence:

Sympathetic--sensory-motor–sheathed nerve.Differentialnerveblockadelevel:Sympatheticblockadethatmaybetwo segments levelhigherthanthesensory block,whichinturn istwosegments higherthanthemotorblockade.16

Respiratorysystem:

1.Lowspinalblockorlowepiduralblock hasno effectontherespiratorysystem.2.Motorblockadeextendingtotherootsof thephrenicnerves(C3-5)causesapnea.3. Highthoraciclevelblockadecancause lossofintercostalmuscleactivity,there isamarkeddecreaseinvitalcapacity.17Cardiovascularsystem:

1.Reductionincardiacoutputandcardiac contractility.2.Bradycardia.(blockT4~T1).3.Decreasebloodpressure.

18GastrointestinalsystemIncreaseintestinalcontraction.2.Nausea,retchingorvomiting:19SpinalAnesthesia20SpinalAnesthesia(spinalblockorsubarachnoidblock,SAB)SABisatypeofregionalanesthesia,whichisachievedbyinjectingalocalanestheticintothelumbarsubarachnoidspace.21ThetermforSABlevel:

BlockleveloverT4ishighlevelSABBlocklevelunderT10islowlevelSABBlockregiononlycovertheperineum &buttockissaddleblockBlockonlyoccurinunilaterallower extremityis

unilateral

block.22

Patient’sposition

forSABPuncture

LateralpositionSittingposition23Thesiteofspinal puncture

L2-L3space(adult)L3-L4space(child)24LocalanestheticsolutionsforSABSolutionbaricity:

(Thespecificgravityof

CSFis1.003~1.009at37℃.)1.HyperbaricsolutionAdditionof5%or10%glucosesolutiontoalocal anestheticsolution(powder)producesa solutionwithspecificgravityof1.024or greater, this solutionisheavierthan CSF.

25Ahypobaricsolution LighterthanCSF,itcanbemadebythepowderanestheticplusofsterilewaterorthepurelocalanestheticsolution.3.Anisobaric(plain)solutionAnestheticagents are mixedwithCSF(atleast1:1).26HyperbaricsolutionsforSABProcaine(powder):100~150mg+5%~10% glucose2.7ml+0.1% Epinephrine0.3ml. Duration:45~90min.

Tetracaine(powder):10~15mg(withCSF1ml)+10% glucose1ml +3%ephedrine1ml.(1+1+1solution). Duration:120~240min

Bupivacaine(solution):0.75%1.5~2ml+

5~10% glucose1~1.5ml. Duration:100~150min

27Vasoconstrictors:Epinephrine&EphedrineBothagentsappeartodecreasetheuptakeand clearanceoflocalanesthetics fromCSF.Additionofvasoconstrictorsinlocal anestheticsolutioncanprolongthe durationofspinal anesthesia.Dosage:Epinephrine0.1~0.3mg.

Ephedrine10~30mg.28Assessingblockadelevel:

Thesensorylevelofblockadecanbe assessed withpinprickorice,the levelof sympathectomy isassessed bymeasuring skintemperature.Thecompleteblockofmotornervesis manifested inabilitytomovethe legsorfoot.Typically,theblockadelevelistransection.29Factorsaffectingspreadofhyperbaricspinalsolution

Patient’sposition“saddleblock” keepingthepatient sittingfor 3~5minafterinjectionof2~3mlof hyperbaricsolution.“unilateral

block”

keepingthepatient

on lateralposition.

302.Drugdosage&solutionvolume.3.Speedofinjection.Therateofinjectionis1ml/

5sec.4.Lumberpuncturesite.5.Needlebeveldirection.31SABlevelmanagement

(Hyperbaricsolution)32ComplicationsofSABHypotensionReasons:vesselsdilatation;increasedbloodpooling; bloodflow decreasedreturntoheart.Cardiac contractilitydecreased.Augmentedby:HypovolemiaChangesinpositionBradycardia

33Treatment:

Prevention:Useofcrystalloidorcolloid fluids10~20ml/kgIV.forvolume loadingpre-lumberpunctureoroperation.Increasefluidadministration.Maskoxygeninhale.Drug:Ephedrine10~15mgIV.342.BradycardiaReasons:SpinalblocklevelhigherthanT4,whichmay blockthecardiac sympathetic accelerator fibers(T1~ T4),thenbradycardia mayoccur.SABdoesnotblockthevagalnerve. Unopposed vagaltoneincreasedisanother reason for bradycardia.35Treatment:

Atropine0.25~0.5mgiv.

Ephedrine15~30mgiv.363.NauseaandvomitingReasons:Increasedvagaltone.Hypotension.Operationirritation.Hypoxemia.Treatment:

CheckBP&HR.Atropine0.25~0.5mg.iv.Ephedrine15mg~30mg.iv.Maskoxygeninhale.374.Headache(Post–duralpunctureheadache,PDPH)Theincidencerateisabout20~30%.Headachemayoccurafterduralpuncture,presumablysecondarytothetearintheduraandthatresultfromdecreasedintracranialpressureasCSFleakfromtheduraldefect,whichmaycausetractiononthemeningesandcranialnerves.38Clinicalcharacteristics:

Theonsettimein12~72hours.persistforupto1~6weeks.Theheadacheisaggravatedbysittingor standing.Relievedorlessenedbylyingdownflat.

39Treatment:ravenousororalfluidadministration.epiduralbloodpatchtreatment.asalinebolusepiduralspaceinjection.sedative&analgesicagent.405.UrinaryretentionReasons:BlockofS2~S4rootfibersdecreases urinarybladdertoneandinhibitsthe voidingreflex.Associatedwiththesurgicalprocedure.Urinaryretentionisusuallytemporary.Persistentbladderdysfunctionmaybea neuralinjury.Treatment:aurethralcatheterinserted.416.NeurologiccomplicationsCaudaequinasyndromeMeningitisArachnoiditisCranialnervepalsy42

Indications&ContraindicationsIndications:lowerabdomenoperation.perineumoperation.lowerlimbsoperation.43

Contraindications

Infectionatthesiteofpuncture.Bleedingdiathesisorcoagulopathy.Severehypovolemia.Severecardiovasculardiseases.Severespinaldeformity.Preexistingneurologicdiseases.Intracranialhighpressure.44EpiduralAnesthesia45ConceptEpiduralanesthesiaisachievedbyinjectingalocalanestheticintotheepiduralspace,whichblocksthespinalnerveroots,producingregionalanesthesia.46Epiduralblock

methods

asingle-shotinjectivetechniques.acontinuousinfusion&intermittent bolustechniques. “Acatheterinserttotheepiduralspaceforcontinuousinfusionorintermittentbolusinjection.”47

Epiduralanestheticagents1.Lidocaine:short–tointermediate-actingagent.concentrationof1.5~2.0%withadrenaline 1:200,000.anesthesiaduration90~150min.totaldosagelimited400mginadult.48Bupivacainelong-actinglocalanesthetic.0.5%~0.75%.onsettimeis10~15min.durationisabout120~150min.dosagelimited150mginadult.49Ropivacaine

newamidelocalanestheticwithaless cardiac toxicitythanbupivacaine. slowonsettimeandlonganesthesia duration.use0.5%~0.75%Dosagelimited150~200mginadult.

50AdministrationoflocalanestheticThequantityoflocalanestheticneedforepiduralanesthesiaisrelativelylargercomparedwithspinalanesthesia.Severecomplicationcanoccuriflargeamountofanestheticisinjectedtosubarachnoidspaceorintravascular.Safeguardsaretheepiduraltestdoseandincrementaldosing(ormaindose).51TestdoseAim:todetectwhethersubarachnoidinjection.todetectwhether

intravascularinjection.Method:3~4ml2%lidocainewith1:200,000epinephrine(5μg/ml)isinjectedtoepiduralspace.ifinjectedintosubarachnoidspace,thatwillproducespinalanesthesiarapidly.The15μg~20μgofepinephrine,ifintravascularinjected,anoticeableincreaseinheartrateproduced.52Incrementaldose

Incrementaldoseisaveryeffectivemethodofavoidingseriouscomplication.After5~10minoftestdosegiven,thereisnosystemtoxicity&nosignsofspinalanesthesiaoccursthentheincrementaldosecanbeinjectedintoepiduralspace.53FactorsaffectingblockinglevelofanesthesiaVolume: inadults,1～2mloflocalanestheticpersegmenttobeblockedisagenerallyacceptedguideline. Forexample,toachieveaT4toL4～L5sensorylevelblocked,requireabout12～24mlinjection.

54Age: Thedoserequiredtoachievethesame levelofanesthesiadecreaseswithage.Thisisprobablyaresultofage-relateddecreasesinthesizeorcomplianceoftheepiduralspace.Sotheolderpatientsrequireslesslocalanesthetic.

553.Height:Thepatientheightaffectstheextentofcephaladspread.Thustheshorterpatientsmayrequiresonly1mloflocalanestheticpersegmenttobeblocked,whilethetallerpatientgenerallyrequires2mlpersegment.Pregnancy:Requireslessvolumeofanesthetic.Becausetheepiduralspacevenousdilatationanditispressureincreasedbypregnancy,itisaugmentedtheanestheticspreadingwider.56Anesthesialevel&PuncturesiteHighlevelepiduralblock(C5~T6).Middlelevelepiduralblock(T6~T12).Lowlevelepiduralblock(L1~).Caudalblock.57Failedepiduralblocksmisplacedinjectionunilateralblocksegmentalsparingvisceralpain58ComplicationsIntraoperativecomplications1.Duraltap

Theepiduralneedlepuncturetheduramater &subarachnoidmaterandentersinto subarachnoid space.Itcanbe recognized byfree flowofCSFdripsfromthe needle.Anepiduralcathetermightpuncturethe dural.592.Totalspinalanesthesia(TSA)Allofthenerveroots&brainsteambeblockedbylargevolumeoflocalanestheticinjectedintosubarachnoidspace.Signsandsymptoms:severehypotension.severe

bradycardia.Apnea.lossofconsciousness.cardiacarrest.60TreatmentofTSASteps:A. Keepingtheairwaypatency,maintaining

adequateventilationandgivingoxygen.B.Supportingcirculation:Infusionofintravenousfluidsquickly.UsevasopressorsbyIV.C.Ifcardiacarrestoccurs,CPRmustbe immediatelyperformed.61PreventionofTSAstrictlyusingthetestdoseoflocal anesthetic.aspirationthecatheterbefore injection .carefullyobservingpatientafterinjected localanesthetic.623.ToxicreactionReasons:intravascularinjection.absorptionofexcessiveamountsofanesthetic.Clinicalcharacteristics numbnessortinglingoftongue.tinnitus,lingualsensations&lightheaded.consciousnesslost.convulsion.63Preventionaspiratingtheneedleorcatheter.usingtestdose.observingearlysignsoftoxicity.Managementoxygeninhale.patencyairway.sedative&anti-convulsionagents.keepingcirculationstable.644.Hypotension

Managementcrystalloidorcolloidsolution.IV.Infusionephedrine15-30mgIV.atropine0.25-0.5mgIV.Oxygeninhale.

655.NauseaorvomitingReasons:hypotensionvisceralmanipulationhypoxemiaManagementincreasefluidtransfusioninhaleoxygendrugusage:atropine,efedrina, antiemetics.666.Respiratorydepression

Reasonshighlevelofepiduralanesthesia.ClinicalsignsSO2%decreased,tidalvolumedecreased,orapnea.Managementavoidhighblocklevel.decreaseanestheticdrugconcentration.oxygeninhale&respiratorysupport.67Postoperativecomplications

HeadacheReasonfollowingduratap.Managementlyinginbed.liquidinfusion.sedative&analgesiaagents.epiduralbloodpatch.

68NeurologicinjuryReasons:Puncturetraumatospinalroot,nervefibersorspinalcord.nerveinjuryresultfromthedirect effectoflocalanesthetics.ManagementPrevention.Consulatationneurologicphysician.

693.

EpiduralhematomaReasons:

abnormalcoagulationor bleeding disorder.