AnesthesiologyYinNingSOUTHEASTUNIVERSITY,ZHONGDAHOSPITALSurgeryBeforeAnesthesiaFunandFrolicsledtoEarlyAnesthesiaJosephPriestly–discoversN2Oin1773CrawfordW.Long–1842.CountryDr.inGeorgiafirstusedetherfornecksurgery.Didnotpublicize,inpartbecauseofconcernsaboutnegativefalloutfrom“frolics”.TriedtoclaimcreditafterMorton’sdemonstrationbut… Importantlessonlearned–ifyoudon’tpublishit,itdidn’thappen.SirHumphreyDavy–experimentedwithN2O,reportedlossofpain,euphoriaTravelingshowswithN2O(1830’s–1840’s) Colt(ofColt45fame)HoraceWells1844.DemonstratedN2Ofortoothextraction–deemedafailurebecausepatient“reacted”.HistoryofAnesthesia(150yearsold)WilliamMorton,dentist–firstdemonstrationofsuccessfulsurgicalanesthesiawithether1846JohnC.Warren,surgeonatMGHsays“Gentlemen,thisisnohumbug!”–birthofmodernanesthesiaDr.JohnSnowadministerschloroformtoQueenVictoria(1853)–popularizesanesthesiaforchildbirthinUKHebecomesthefirstanesthesiaspecialist.NotethatetherbecameanesthesiaofchoiceinUS,chloroforminUKHistoryofAnesthesia

Theevolutionofmodernanesthesiologymaybedevidedinto3stages:

1、anesthesia

2、Clinicalanesthesiology

3、anesthesiologyandcriticalcaremedicine

departmentofanesthesiologyandresuscitation

departmentofanesthesiologyandcriticalcaremedicine.

AnesthesiaAllowsurgical,obstetricalanddiagnosticprocedurestobeperformedinamannerwhichispainlesstothepatientAllowcontroloffactorssuchasphysiologicfunctionsandpatientmovementGeneralanesthesiaRegionalanesthesiaLocalanesthesiaConsciousSedation(monitoredanesthesiacare)AnesthetictechniquesAnesthetictechniguemaybeclassifiedasfollows:

General

anesthesia.inhalationalanesthesia .intravenousanesthesia .intramuscularanesthesia.rectalanesthesia

Localanesthesia ·topicalanesthesia ·localinfiltration ·fieldblock

(peripheral)nerveblocks intravenousregionalanesthesia Insometextbooksandmonographs,nerveblocks,spinalanesthesiaandepiduralanesthesiaarecollectivelycalled“regionalblook”or“regionalanesthesia”

Everydayexpressionsortermsincommonuse;balancedanesthesia combinedanesthesia basalnarcosis endotrachealanesthesia endotrachealintubation endoBronchialanesthesia 2.1classificationsaccordingtothesubspecialtyofclinicalanesthesiologysuchas:.anesthesiaforcardiacsurgery anesthesiaforVascularsurgery anesthesiaforthoracicsurgery neurosurgicalanesthesia anesthesia fororgantransplantation

anesthesiaforendocrinesurgeryobstetricanesthesia pediatricanesthesia geriatricanesthesia anesthesiafororthopedicsurgery anesthesiaforabdominalsugery anesthesiafortrauma andsoonTheanaesthetist’sDutyToensurepatientsafetyTosafeguardpatientwelfareTooptimiseoperatingconditionsTopreventinjuryToactastheperoperativephysicianPreparationforAnaesthesiaGeneralHistoryandclinicalsigns:assessmentA?AffirmativehistoryA?AirwayB?Bloodhemoglobin,bloodlossestimation,andbloodavailabilityB?BreathingC?ClinicalexaminationC?Co?morbiditiesD?DrugsbeingusedbythepatientD?DetailsofpreviousanesthesiaandsurgeriesE?EvaluateinvestigationsE?EndpointtotakeupthecaseforsurgeryF?FluidstatusF?FastingG?GivephysicalstatusG?GetconsentProperativeinvestigationBloodcountPotassium,sodiumBiochemicalscreenElectrocardiogramChestradiographSerumforcross-matchHepatitisBantigenSicklecellscreenBloodgastensionsMedicalcheck-listCardiovascular-hypertension,angina,arrhythmias,failureRespiratory–infection,asthmaGastroinstestinal–regurgitation,bowelobstruction,jaundiceMetabolic–porphyria,hyperpyrexia,phaeochromocytama,steroids,diabetesCoagulation-hereditaryandacquiredNeurological-consciousnesslevel,cervicalinstabilityPsychiatric–effectofdrugsStarvationbeforesurgery6hfood4hfluid,2h(clear,non-fizzyfluid)PreoperativedrugsandtreatmentPreperativesedativeandanalgesicmedication:BenzodiazepinesTheanticholinergicagents:AtropineAntithromboticprophylaxis:subcutaneousheparin美國(guó)麻醉師協(xié)會(huì)（ASA）于麻醉前根據(jù)病人體質(zhì)狀況和對(duì)手術(shù)危險(xiǎn)性進(jìn)行分類，共將病人分為六級(jí)。ASA分級(jí)標(biāo)準(zhǔn)是：第一級(jí)：體格健康，發(fā)育營(yíng)養(yǎng)良好，各器官功能正常。圍手術(shù)期死亡率0.06%-0.08%；第二級(jí)：除外科疾病外，有輕度并存病，功能代償健全。圍手術(shù)期死亡率0.27%-0.40%；第三級(jí)：并存病情嚴(yán)重，體力活動(dòng)受限，但尚能應(yīng)付日常活動(dòng)。圍手術(shù)期死亡率1.82%-4.30%；第四級(jí)：并存病嚴(yán)重，喪失日常活動(dòng)能力，經(jīng)常面臨生命威脅。圍手術(shù)期死亡率7.80%-23.0%；第五級(jí)：無(wú)論手術(shù)與否，生命難以維持24小時(shí)的瀕死病人。圍手術(shù)期死亡率9.40%-50.7%；第六級(jí)：確證為腦死亡，其器官擬用于器官移植手術(shù)。ASA分級(jí)評(píng)估—術(shù)前體能狀態(tài)評(píng)估MET(metabolicequivalent)：所有活動(dòng)過(guò)程中耗氧量之基本單位，靜息時(shí)基本耗氧量3.5ml/kg/分1～4MET:

僅能自己穿衣吃飯入廁，平地慢走（3～4Km/h）或稍活動(dòng)，甚至休息時(shí)即發(fā)生心絞痛4～7MET:

能上三層樓，平地走6Km/h7MET：能短距離跑步，短時(shí)間玩網(wǎng)球或打籃球

評(píng)估—術(shù)前體能狀態(tài)評(píng)估DASI(DukeActivityStatusIndex)

預(yù)測(cè)圍手術(shù)期并發(fā)癥判斷標(biāo)準(zhǔn)大于7MET表明體能良好，圍手術(shù)期心血管事件發(fā)生率低；4~7MET為中等體能，有一定發(fā)生率；4MET以下，則心血管危險(xiǎn)大幅度增加。

（2014ESC/ESAGuidelinesonnon-cardiacsurgery:cardiovascularassessmentandmanagement)評(píng)估—術(shù)前體能狀態(tài)評(píng)估—虛弱虛弱的的確立標(biāo)準(zhǔn)：1.無(wú)意識(shí)的體重丟失>10磅2.通過(guò)握力測(cè)量虛弱3.活動(dòng)疲憊4.輕體力活動(dòng)5.測(cè)量15秒慢步行走的速度。評(píng)估—虛弱Makary等用5點(diǎn)評(píng)分將擇期手術(shù)的病人分為三組：體弱，中等脆弱，非體弱。觀察30天內(nèi)手術(shù)并發(fā)癥的發(fā)生率，住院天數(shù)。他們發(fā)現(xiàn)，身體虛弱的病人有較高的不良事件發(fā)生率，較長(zhǎng)的出院時(shí)間。脆弱性指數(shù)提高了更加標(biāo)準(zhǔn)的風(fēng)險(xiǎn)指數(shù)的預(yù)測(cè)價(jià)值。MartinA.Makary,FrailtyasaPredictorofSurgicalOutcomesinOlderPatientsJournaloftheAmericanCollegeofSurgeons,2010,210(6):901~908GeneralAnestheticsNouniversallyaccepteddefinitionUsuallythoughttoconsistof:OblivionAmnesiaAnalgesiaLackofMovementHemodynamicStabilityWhatis“Anesthesia”Sensory-AbsenceofintraoperativepainCognitive:-Absenceofintraoperativeawareness-AbsenceofrecallofintraoperativeeventsMotor:-Absenceofmovement-AdequatemuscularrelaxationAutonomic:-Absenceofhemodynamicresponse-Absenceoftearing,flushing,sweatingWhatis“Anesthesia”Hypnosis(unconsciousness)AmnesiaAnalgesiaImmobility/decreasedmuscletone(relaxationofskeletalmuscle)InhibitionofnociceptivereflexesReductionofcertainautonomicreflexes(gagreflex,tachycardia,vasoconstriction)GoalsofGeneralAnesthesiaPathwayforGeneralAnestheticsRapidinductionSleepAnalgesiaSecretioncontrolMusclerelaxationRapidreversalDesiredEffectsOfGeneralAnesthesia(BalancedAnesthesia)AnesthesiaMachineInduction-initialentrytosurgicalanesthesiaMaintenance-continuousmonitoringandmedicationMaintaindepthofanesthesia,ventilation,fluidbalance,hemodynamiccontrol,homeostasisEmergence-resumptionofnormalCNSfunctionExtubation,resumptionofnormalrespirationPhasesofGeneralAnesthesiaStagesOfGeneralAnesthesiaIntravenousSafe,pleasantandrapidMaskCommonforchildrenunder10Mostinhalationalagentsarepungent,evokecoughingandgaggingAvoidstheneedtostartanintravenouscatheterbeforeinductionofanesthesiaPatientsmayreceiveoralsedationforseparationfromparents/caregiversIntramuscularUsedinuncooperativepatientsRoutesofInductionInhalationanesthesiaAnestheticsingaseousstatearetakenupbyinhalationTotalintravenousanesthesiaInhalationplusintravenous(“BalancedAnesthesia”)MostcommonAnestheticTechniquesAnestheticdrugshaverapidonsetandoffset“Minutetominute”controlisthe“holygrail”ofgeneralanesthesiaAllowsrapidadjustmentofthedepthofanesthesiaAbilitytoawakenthepatientpromptlyattheendofthesurgicalprocedureRequiresinhalationanestheticsandshort-actingintravenousdrugsDuringthemaintenancephase,anestheticdosesareadjustedbaseduponsignsofthedepthofanesthesiaMostimportantparameterformonitoringisbloodpressureThereisnoprovenmonitorofconsciousnessAnestheticDepthSafestforthepatientAppropriatedurationi.v.inductionagentsforshortproceduresFacilitatessurgicalprocedureMostacceptabletothepatientGeneralvs.regionaltechniquesAssociatedcostsSelectionofanesthetictechnique氣道評(píng)估：病史：

打鼾史；睡眠呼吸暫停綜合癥；氣道手術(shù)史；頭頸部放療史；麻醉史等。體檢評(píng)估方法（常用六種方法）：

1、改良Mallampati分級(jí)

2、張口度

3、甲頦間距（Thyromentaldistance)4、下顎前伸幅度

5、寰椎關(guān)節(jié)伸展度

6、喉鏡檢查（Laryngoscopicviewgradingsystem）改良Mallampati分級(jí)：

病人面對(duì)麻醉師，用力張口伸舌至最大限度（不發(fā)音），根據(jù)所能見(jiàn)咽部結(jié)構(gòu)分級(jí)：分級(jí)所見(jiàn)結(jié)構(gòu)I級(jí)可見(jiàn)軟腭，咽腭弓，懸雍垂II級(jí)可見(jiàn)軟腭，咽腭弓，部分懸雍垂III級(jí)僅能見(jiàn)軟腭IV級(jí)看不見(jiàn)軟腭III、IV級(jí)為困難氣道張口度：

間距小于3cm屬困難插管ManagementofairwayduringanesthesiaMouthtobronchus:facemaskandoropharyngelairway;Laryngealmask;oro-ornasotrachealtube(cuffinflated);cuffedtracheostomytube;Double-lumenrightendobronchialtube(trachealandbronchialcuffs)EndobronchialtubeThelaryngealmaskairway(LMA)TarachealtubesMaskOratrachealtubeNasotrachealtubeTrachestomytubelaryngendoscopeBronchoscopyEndotrachealintubationcomplicationAccidentalandunrecognisedoesophagealintubation;Accidentalintubationofmainbronchus;traumatolarynx,tracheaorteeth;Aspirationofvomitusduringintubation;Failuretointubatethetrachea,accidentalintubationoftheoesophagusandlossofairwaycontrol;Disconnectionorblockageofthetube;DelayedtrachealstenosisinchildrenorafterprolongedintubationNeuromuscularblockingdrugsExtractofvines(Strychnostoxifera;alsoChondrodendronspecies)UsedbyindegenouspeoplesofAmazonbasininpoisonarrows(notorallyactive,sofoodissafetoeat)BroughttoEuropebySirWalterRaleigh,othersCurare-typedrugs:Tubocurare(bambootubes),Gourdcurare,PotcurareBrody(1811)showedcurareisnotlethalisanimalisventilatedHarley(1850)usedcurarefortetanusandstrychninepoisoningHaroldKing(1935)isolatesd-tubocurarinefromamuseumsample–determinesstructure.0NeuromuscularblockingdrugsBlocksynaptictransmissionattheneuromuscularjunctionAffectsynaptictransmissiononlyatskeletalmuscleDoesnotaffectnervetransmission,actionpotentialgenerationActatnicotinicacetylcholinereceptorNII0Neuromuscularblockingdrugs0AcetylcholineisreleasedfrommotorneuronsindiscretequantaCauses“all-or-none”rapidopeningofNa+/K+channels(duration1msec)Developmentofminiatureend-platepotentials(mEPP)SummatetoformEPPandmuscleactionpotential–resultsinmusclecontractionAChisrapidlyhydrolyzedbyacetylcholinesterase;norebindingtoreceptoroccursunlessAChEinhibitorispresentDepolarizingNeuromuscularblockingdrugs0Succinylcholine,decamethoniumBindtomotorend-plateandcauseimmediateandpersistentdepolarizationInitialcontraction,fasciculationsMuscleistheninadepolarized,refractorystateDesensitizationofAchreceptorsInsensitivetoK+,electricalstimulationParalyzesskeletalmorethanrespiratorymusclesSuccinlycholine:PharmacokineticsFastonset(1min)Shortdurationofaction(2to3min)Rapidlyhydrolyzedbyplasmacholinesterase0Succinylcholine:PhaseIIblockProlongedexposuretosuccinlycholineFeaturesofnondepolarizingblockadeMaytakeseveralhourstoresolveMayoccurinpatientsunabletometabolizesuccinylcholine(cholinesterasedefects,inhibitors)Harmlessifrecognized0AcetylcholinesteraseinhibitorsAcetylcholinesteraseinhibitorshavemuscariniceffectsBronchospasmUrinationIntestinalcrampingBradycardiaPreventedbymuscarinicblockingagent0Non-depolarizingNeuromuscularblockingdrugs0Competetiveantagonistofthenicotinic2receptorBlocksAChfromactingatmotorend-plateReductionto70%ofinitialEPPneededtopreventmuscleactionpotentialMuscleisinsensitivetoaddedAch,butreactivetoK+orelectricalcurrentAChEinhibitorsincreasepresenceofACh,shiftingequilibriumtofavordisplacingtheantagonistfrommotorend-plateNondepolarizingdrugs:MetabolismImportantinpatientswithimpairedorganclearanceorplasmacholinesterasedeficiencyHepaticmetabolismandrenalexcretion(mostcommon)Atracurium,cis-atracurium:nonenzymatic(Hoffmanelimination)Mivacurium:plasmacholinesterase00MonitoringduringanaesthesiaItisessentialtomonitorphysiologicalfunctionsduringallanaesthesiaEvenforproceduresundersedation,basicmonitoringisessentialThecontinouspresenceofanadequatelytrainedanesthetist;Regularbloodpressureandheartratemeasurements;ContinuousmonitoringofECGthroughoutanaesthesia;Continuousanalysisofoxygencontentandanaestheticintheinspiratorygasmixture;Oxygensupplyfailurealarm;VentilatordisconnectionalarmPulseoximeter;Capnography(measurementofend-tidalcarbondioxidecontent)TemperaturemeasurementavailabilityNeuromuscularmonitoringavailabilityCardiacmonitoringRespiratoryparametersRecoveryfromgeneralanaesthesiaObstructionfotheairwayCentralsedationfromopioiddrugsoranaestheticagents;Hypoxiaorhypercarbiaofanycause;HypocarbiaformmechanicaloverventilationPersistentneuromuscularblockade;PneumothoraxfrompleuraldamageduringanaesthesiaorsurgeryCirculatoryfailureleadingtorespiratoryarrestThecommoncausesoffailuretobreatheaftergeneralanaesthesia:ManagementofbloodpressureintherecoveryroomHypotension:Hypovolaemia,prolongvasodilatation,myocardialdepressant,cardiacdyshythmia,hypoxaemia

Hypertension:pain,fear,coldorshiveringorpre-existinghypertensivediseaseGeneralanaesthesiaforday-casesurgeryDay-casesurgeryFullpreparationisessentialAnaesthesiashouldbetailoredtothepatient’sneedNosedationisrequiredConsiderationshouldbegiventoappropriateanalgesiafast-trackinganesthesiaLocal/RegionalAnestheticsLocalAnestheticsObjectivesClassifyeachlocalasanesteroramideStatethemechanismofactionforlocalanestheticsStatethemetabolismforesters&amidesIdentifyrankingofabsorptionbyarterialflowforgiveanatomicregionsDiscusshowlipidsolubilityandvasoconstrictionaffectthepotencyanddurationoflocalsDiscusstheetiologyofanallergicreactiontolocalanestheticsUnderstandhowpKaeffectsspeedofonsetoflocalsGeneralconceptsCocaineisolatedfromErythroxyloncocaplantinAndesVonAnrep(1880)discoverslocalanestheticproperty,suggestsclinicaluseKollerintroducescocaineinopthalmologyFreudusescocainetoweanKarlKolleroffmorphineHalsteaddemonstratesinfiltrationanesthesiawithcocaineRapidlyacceptedindentistryGeneralconceptsHalstead(1885)showscocaineblocksnerveconductioninnervetrunksCorning(1885)demonstratesspinalblockindogs1905:Procaine(NOVOCAINE)synthesizedanalogofcocainebutwithouteuphoric effects,retainsvasoconstrictoreffectSlowonset,fastoffset,ester-type(allergicreactions)GeneralconceptsFirst“modern”LA(1940s):lidocaine(lignocaineinUK;XYLOCAINE)Amidetype(hypoallergenic)Quickonset,fairlylongduration(hrs)MostwidelyusedlocalanestheticinUStoday,alongwithbupivacaineandtetracaineGeneralconceptsCausetransientandreversiblelossofsensationinacircumscribedareaofthebodyVerysafe,almostnoreportsofpermanentnervedamagefromlocalanestheticsInterferewithnerveconductionBlockalltypesoffibers(axons)inanerve(sensory,motor,autonomic)Localanesthetics:UsesTopicalanesthesia(cream,ointments,EMLA)PeripheralnerveblockadeIntravenousregionalanesthesiaSpinalandepiduralanesthesiaSystemicuses(antiarrhythmics,treatmentofpainsyndromes)StructureAlllocalanestheticsareweakbases.Theyallcontain:Anaromaticgroup(conferslipophilicity) -diffusionacrossmembranes,duration,toxicityincreaseswithlipophilicityAnintermediatechain,eitheranesteroranamide;andAnaminegroup(confershydrophilicproperties) –chargedformisthemajoractiveformStructurePKa%RNatPH7.4OnsetinminutesMepivicaine7.6402to4Etidocaine7.7332to4Articaine7.8292to4Lidocaine7.9252to4Prilocaine7.9252to4Bupivicaine8.1185to8Procaine9.1214to18

FormulatedasHClsalt(acidic)forsolubility,stabilityBut,uncharged(unprotonatedN)formrequiredtotraversetissuetositeofactionpHofformulationisirrelevantsincedrugendsupininterstitialfluidQuaternaryanalogs,lowpHbathingmediumsuggestsmajorformactiveatsiteiscationic,butbothchargedandunchargedspeciesareactiveStructure

ModeofactionBlocksodiumchannelsBindtospecificsitesonchannelproteinPreventformationofopenchannelInhibitinfluxofsodiumionsintotheneuronReducedepolarizationofmembraneinresponsetoactionpotentialPreventpropagationofactionpotentialModeofactionChoiceoflocalanestheticsOnsetDurationRegionalanesthetictechniqueSensoryvs.motorblockPotentialfortoxicityClinicaluseChoiceoflocalanestheticsFactorsinfluencinganestheticactivityNeedleinappropriatelocation(mostimportant)DoseoflocalanestheticTimesinceinjectionUseofvasoconstrictorspHadjustmentNerveblockenhancedinpregnancyCardiovasculartoxicityDepressedmyocardialcontractilitySystemicvasodilationHypotensionArrhythmias,includingventricularfibrillation(bupivicaine)RedistributionandmetabolismRapidlyredistributedMoreslowlymetabolizedandeliminatedEstershydrolyzedbyplasmacholinesteraseAmidesprimarilymetabolizedintheliverLocalanesthetictoxicityAllergyCNStoxicityCardiovasculartoxicityAllergyEsterlocalanestheticsmayproducetrueallergicreactionsTypicallymanifestedasskinrashesorbronchospasm.MaybeassevereasanaphylaxisDuetometabolismtoρ-aminobenzoicacidTrueallergicreactionstoamidesareextremelyrare.SystemictoxicityResultsfromhighsystemiclevelsFirstsymptomsaregenerallyCNSdisturbances(restlessness,tremor,convulsions)-treatwithbenzodiazepinesCardiovasculartoxicitygenerallylaterCNSsymptomsTinnitusLightheadedness,DizzinessNumbnessofthemouthandtongue,metaltasteinthemouthMuscletwitchingIrrationalbehaviorandspeechGeneralizedseizuresComaAvoidingsystemictoxicityUseacceptabletotaldoseAvoidintravascularadministration(aspiratebeforeinjecting)AdministerdrugindivideddosesMaximumsafedosesoflocalanestheticsinadultsUsesofLocalAnestheticsNerveblockanesthesia -Injectanestheticaroundplexus(e.g.;brachialplexusforshoulderandupperarm)toanesthetizealargerarea -Lidocaine,mepivacaineforblocksof2to4hrs,bupivacaineforlongerBierBlock(intravenous) -usefulforarms,possibleinlegs -Lidocaineisdrugofchoice,prilocainecanbeused -limbisexsanguinatedwithelasticbandage,infiltratedwithanesthetic -tourniquetrestrictscirculation -doneforlessthan2hrsduetoischemia,painfromtouniquetSpinalanesthesia -InjectanestheticintolowerCSF(belowL2) -usedmainlyforlowerabdomen,legs,“saddleblock” -Lidocaine(shortprocedures),bupivacaine(intermediatetolong),tetracaine(longprocedures) -Rostralspreadcausessympatheticblock,desirableforbowelsurgery -riskofrespiratorydepression,posturalheadacheUsesofLocalAnestheticsEpiduralanesthesia-Injectanestheticintoepiduralspace-Bupivacaine,lidocaine,etidocaine,chloroprocaine-selectiveactionofspinalnerverootsinareaofinjection-selectivelyanesthetizesacral,lumbar,thoracicorcervicalregions-nerveaffectedcanbedeterminedbyconcentration-Highconc:sympathetic,somaticsensory,somaticmotor-Intermediate:somaticsensory,nomotorblock-lowconc:preganglionicsympatheticfibers-usedmainlyforlowerabdomen,legs,“saddleblock”-Lidocaine(shortprocedures),bupivacaine(intermediatetolong),tetracaine(longprocedures)-Rostralspreadcausessympatheticblock,desirableforbowelsurgery-riskofrespiratorydepression,posturalheadacheUsesofLocalAnestheticsSpinalAnatomy33Vertebrae7Cervical12Thoracic5Lumbar5Sacral4CoccygealHighPoints:C5&L5LowPoints:T5&S2SpinalCordSpinalCordAdultBegins:ForamenMagnumEnds:L1NewbornBegins:ForamenMagnumEnds:L3TerminalEnd:ConusMedullarisFilumTerminale:AnchorsinsacralregionCaudaEquina:NervegroupoflowerduralsacSaggitalSectionsSupraspinousLigamentOutermostlayerIntraspinousLigamentMiddlelayerLigamentumFlavumInnermostlayerEpiduralSpaceSpacethatsurroundsthespinalmeningesPotentialspaceLigamentumFlavumBindsepiduralspaceposteriorlyWidestatLevelL2(5-6mm)NarrowestatLevelC5(1-1.5mm)SpinalMeningesDuraMaterOutermostlayerFibrousArachnoidMiddlelayerNon-vascularPiaInnermostlayerHighlyvascularSubArachnoidSpaceLiesbetweenthearachnoidandpiaSpinalPharmacologyVasoconstrictorsProlongdurationofspinalblockNoincreaseindurationwithlidocaine&bupivacaineSignificantincreasewithtetracaine(doubleduration)SpinalPharmacologyFactorsEffectingDistributionSiteofinjectionShapeofspinalcolumnPatientheightAngulationofneedleVolumeofCSFCharacteristicsoflocalanestheticDensitySpecificgravityBaracityDoseVolumePatientposition(during&after)SpinalPharmacologyAnesthesialevelisdeterminedbypatientpositionUptakeoflocalanestheticoccursbydiffusionEliminationdeterminesdurationofblockLipidsolubilitydecreasesvascularabsorptionVasoconstrictioncandecreaserateofeliminationCardiovascularEffectsBlockadeofSympatheticPreganglionicNeuronsSendsignalstobotharteriesandveinsPredominantactionisvenodilationReduces:VenousreturnStrokevolumeCardiacoutputBloodpressureT1-T4BlockadeCausesunopposedvagalstimulationBradycardiaAssociatedwithdecreasevenousreturn&cardioacceleratorfibersblockadeDecreasedvenousreturntorightatriumcausesdecreasedstretchreceptorresponse

HypotensionTreatmentBestwaytotreatisphysiologicnotpharmacologicPrimaryTreatmentIncreasethecardiacpreloadLargeIVfluidboluswithin30minutespriortospinalplacement,minimum1literofcrystalloidsSecondaryTreatmentPharmacologicEphedrineismoreeffectivethanPhenylephrineRespiratorySystemHealthyPatientsAppropriatespinalblockadehaslittleeffectonventilationHighSpinalDecreasefunctionalresidualcapacity(FRC)ParalysisofabdominalmusclesIntercostalmuscleparalysisinterfereswithcoughingandclearingsecretionsApneaisduetohypoperfusionofrespiratorycenterSpinalTechniquePreparation&MonitoringEKGNBPPulseOximeterPatientPositioningLateraldecubitousSittingProne(hypobarictechnique)SpinalTechniqueMidlineApproachSkinSubcutaneoustissueSupraspinousligamentInterspinousligamentLigamentumflavumEpiduralspaceDuramaterArachnoidmaterParamedianorLateralApproachSameasmidlineexcludingsupraspinous&interspinousligamentsSpinalAnesthesiaLevelsSpinalAnesthesiaIndications&AdvantagesFullstomachAnatomicdistortionsofupperairwayTURPsurgeryObstetricalsurgery(T4Level)Decreasedpost-operativepainContinuousinfusionSpinalAnesthesiaContraindicationsAbsolute:RefusalInfectionCoagulopathySeverehypovolemiaIncreasedintracranialpressureSevereaorticormitralstenosisRelative:UseyourbestjudgmentSpinalAnesthesiaComplicationsFailedblockBackpain(mostcommon)SpinalheadacheMorecommoninwomenages13-40LargerneedlesizeincreaseseverityOnsettypicallyoccursfirstorseconddaypost-opTreatment:BedrestFluidsCaffeineBloodpatchSpinalAnesthesiaFluidTestforCSFReturnClearFreeflowAspirationintosyringeLitmusPaperUrinedipstickTemperatureTaste…Ifyou’remanenough…BloodPatchIncreasepressureofCSFbyplacingbloodinepiduralspaceIfmorethanonepuncturesiteuselowestsiteduetorosteralspreadMaydonomorethantwo95%successwithfirstpatchSecondpatchmaybedone24hoursafterfirstSpinalAnesthesiaSpreadofLocalAnestheticsFirsttocaudaequinaLaterallytonerverootletsandnerverootsMaydefusetospinalcordPrimaryTargets:RootletsRootsSpinalcordEpiduralAnatomySafestpointofentryismidlinelumbarSpreadofepiduralanesthesiaparallelsspinalanesthesiaNerverootletsNerverootsSpinalcordEpiduralAnesthesiaOrderofBlockadeBfibersC&AdeltafibersPainTemperatureProprioceptionAgammafibersAbetafibersAalphafibersEpiduralAnesthesiaTestDose:1.5%LidowithEpi1:200,000Tachycardia(increase>30bpmoverrestingHR)HighbloodpressureLightheadednessMetallictasteinmouthRinginearsFacialnumbnessNote:ifbetablockedwillonlyseeincreaseinBPnotHRBolusDose:PreferredLocalofChoice10millilitersforlaborpain20-30millilitersforC-sectionEpiduralAnesthesiaDistancesfromSkintoEpiduralSpaceAverageadult:4-6cmO