剖腹产的麻醉进展

剖腹产的麻醉进展Introduction

Associatedwithhighmaternalmortality（二十世纪前，剖腹产由于产妇高死亡率，开展得并不多）untiltheturnofthe20thcentury,cesareandeliverynowaccounts

forapproximatelyonethirdofallbirthsin

developedcountries（发达国家三分之一分娩通过剖腹产）

Thisincreasehasresultedfromimprovementsin

surgicalandanesthetictechniques,diminisheduseofforcepsforextractions,fewerbreechandmultiplegestation

vaginaldeliveries,andgreateruseofrepeatcesareandeliveries（得益于外科及麻醉技术的发展、产钳使用的减少、臀位和复杂分娩的减少、以及二次剖腹产的发展）.Introduction

TheupdatedPracticeGuidelinesforObstetricalAnesthesiafromtheASATaskForceonObstetricalAnesthesia

observethatneuraxialtechniques(spinal,epidural,CSE)areassociatedwithimprovedmaternalandfetaloutcomes

whencomparedtogeneralanesthesia(GA)（观察到椎管内麻醉与全麻相比，对于产妇和胎儿有更好的预后）,particularlyinthepresenceofhighbodymassindexandairwayissues（特别是高体重指数和气道问题的病人）.

However,specificanestheticmanagementshouldbechosenonacase-by-caseassessmentofpatient,medical（具体麻醉方式必须建立在对病人完全评估之上）,anesthetic,andobstetricissues.IntroductionAnestheticparticipationcanalsoreducetheincidence、ofcesareandeliveries[e.g.improvingforcep/vacuumanalgesia,increasingthesuccessofmultiplegestationvaginalbirths,reducingfetalheadentrapmentwithintravenousnitroglycerin,andimprovingexternalcephalicversion(ECV)success].(麻醉在自然分娩中的参与同样可以减少剖腹产率，比如为使用产钳时提供镇痛，提高复杂分娩的成功率以及改善胎位不正回转术的成功率)IntroductionNeuraxialtechniquesimproveECVsuccessbyrelaxingtheabdominalwallmuscles,improvingpatientcomfort,andallowingamoreconcertedattempt.（神经阻滞可以松弛腹壁肌肉，提高病人舒适度，从而提高回转术成功率）anesthesia(lidocaine45mgwithfentanyl10μg)combinedwithuterinetocolysis(nitroglycerin50μgiv,wait50sec)hasbeenassociatedwithahighsuccessrate(83%)forexternalcephalicversion(ECV).（使用45mg利多卡因+10ug芬太尼，同时用50ug硝酸甘油抑制子宫收缩，可以使回转术成功率提高到83%）IsthereaPreferredAnestheticTechnique（什么是剖腹产首选麻醉方式）?

Complicationsrelatedtoanesthesiastillrepresentthesixthleadingcauseofperipartummaternalmortalityinthe

UnitedStates（麻醉相关并发症是产妇围生期第六大死亡原因）.

Notsurprisingly,thesedeathsmostcommonlyresultfromfailuresinoxygenationandventilation（通常由氧合或通气失败导致）,however,theseepisodesarecurrentlybeingwitnessedmorefrequentlyduringextubationandpostoperative

recovery,ratherthanwithintubation（通常在拔管及恢复期发现，而不是插管时）.IsthereaPreferredAnestheticTechnique?

Theestimatedcase-fatalityriskratioforGAversusneuraxialanesthesiahasundergoneasignificantreduction（全麻与椎管内麻醉的死亡率比例经历了极大的下降）.

Thischangemostlikelyrepresentstwo

Trends（代表了两种趋势）:

1)areductioninGAuse,coupledwith

moresuccessfulmanipulation(e.g.Alternate

airwaydevices)ofthematernalairway（全麻的减少，和更多气道替代设备的熟练操作）.

2)agrowingacceptanceofneuraxialtechniqueuseinparturientswith

significantcomorbidities(e.g.obesity,severepreeclampsia,hematologicandcardiacdisease)（对合并有包括肥胖，严重子痫前期，凝血功能障碍及心脏病产妇使用椎管内麻醉的接受程度）IsthereaPreferredAnestheticTechnique?

Thecombinedspinalepidural(CSE)techniquemayofferthemostflexibility（腰硬联合提供更多的灵活度）

intermsofreducingtheinitialdrug

dose(通过减少初始剂量），allowingforpotentiallylesshypotensionandfasterrecovery（更少的低血压发生率和更快的恢复）,aswellasprolongingtheblockadeshould

operativecomplications（减少手术并发症）

orpostoperativepainmanagement（术后镇痛管理）

issuesoccur.ShouldNewerLocalAnestheticsbeused（新型局麻药的使用）?

Potentiallyreducedrecoverytimesandtoxicityprofileshavefosteredaninterestinthenewerlocalanesthetics为了减少恢复时间和毒性反应，促使了新型局麻药的发展）,

ropivacaineandlevobupivacaine（罗哌卡因和左布比卡因）.

Althoughestablishedtobesafeandacceptableforelectivecesareandeliveries（虽然被证实剖腹产时更安全）,thesetwolocalanestheticsmaynotbesignificantlylesscardiotoxicthanbupivacaine（并没有比布比卡因明显减少心脏毒性）

Moreover,becausethetoxicityofbupivacainedoesnotappeartobeenhancedinpregnancy（因为布比卡因的毒性在怀孕期并没有增加）,cardiactoxicityshouldonlyoccurwithunintentionallargeintravasculardoses（心脏毒性只在血管内意外大量注射后发生）.ShouldNewerLocalAnestheticsbeused?

Withthecommonandmore

forgivinguseofchloroprocaine3%andlidocaine2%forconversionofepidurallaboranalgesiatocesarean

Anesthesia（随着普鲁卡因和利多卡因作为剖腹产硬膜外麻醉的药物,coupledwithproperdrugadministrationpractices(e.g.attentiontoincrementaldosingpractices,total

doseguidelines,andtoxicitysymptoms，如果掌握正确的给药方式（例如注意追加剂量、总剂量的给药方法、掌握判断毒性反应的方法),toxicintravascularlevelsshouldbearare（血管内毒性水平可以降到很低）.ShouldLowerDosesofBupivacainebeused（低剂量布比卡因的使用）?

Thedoseoflocalanestheticshasbeenreduced

asamethodtopotentiallyobtainlesshypotension,fastermotor

recoveryanddischargetimes,andimprovedmaternalsatisfaction（减少局麻药用量可以作为预防低血压，改善恢复时间和产妇满意度的方法）

Suchdosereductionsmaybeachievedbyusingspinalversusepiduralanesthesia（通过使用腰麻）,aswellaslesstotallocalanesthetic（减少局麻药总用量）;withthesechanges,reductionsintime,costs,andcomplicationshavebeenrealized.

Whenspinalbupivacaineinintermediatetolowdoses(3-9mg)areused（当腰麻布比卡因使用中到低剂量即3-9mg）,theneedforsupplementalmedicationscanbesignificant(可能需要更多追加剂量),andthusacatheterbasedtechnique(以至于需要导管技术比如CSE)shouldbeused.CanHypotensionbeprevented?

（避免低血压）

Neuraxial-inducedhypotension,whensevereandsustainedcanimpairuterineandintervillousbloodflowandresult

infetalhypoxia,acidosis,andneonataldepression（椎管内麻醉后严重并且持续的低血压会影响子宫及绒毛血供，导致胎儿缺血，甚至胎儿窘迫）.

Leftuterinedisplacementandtreatmentorprophylaxiswith

vasopressorshavereducedtheincidenceofhypotensionwithvariablesuccess（子宫左旋或血管加压药可以预防）.

Preloadingwithcrystalloidhas

limitedeffectsonmitigatinghypotension,evenwithlargedoses(即使给予大剂量晶体预充血容量，效果仍然有限);moreeffectiveispreloadingwith

colloids,orsimultaneouslygivingrapidcrystalloidorcolloidscoincident(co-loading)withthespinaltechnique（最好预充胶体液或晶胶同时预充）.CanHypotensionbeprevented？

Hypotension

mayalsobereducedwiththeuseofsmallerspinallocalanestheticdoses（低血压同样可以通过较少的腰麻药用量避免）.

Prophylaxisandtreatmentofmaternal

hypotensionwithphenylephrine（去氧肾上腺素）,versusincombinationwithephedrineorephedrinealone（合用或单用麻黄素）,ismore

effectiveinimprovingmaternalhemodynamics（更好改善母体血流动力学）

andfetalacid-basevalues（胎儿酸碱水平）;WhatAdjuvantMedicationsshouldbeused?辅助用药的使用

Adjuvantmedicationsexpressanumberofbenefits,including

theabilitytoreducethedoseandsideeffectsoflocal

anesthetics（辅助药可以减少局麻药用量和副作用）.

Neostigmineandclonidine（新斯的明和可乐定）

aretwonovelagentsundergoingclinicalinvestigation.

Inwomen

undergoingelectivecesareandelivery,neostigmineinspinaldosesupto100μgsignificantlyreducedpost-operative

pain（显著减少术后疼痛）

withnoeffectonfetalheartrateorApgarscores（对胎儿心率\和Apgar评分无影响）.WhatAdjuvantMedicationsshouldbeused?

However,inspinaldosesaslittleas6.25μg,ahighincidenceofsideeffects

includingprolongedmotorblockade,nausea,andvomitinghavebeenobserved（观察到比如延长的运动阻滞、恶心呕吐等副作用发生率较高）.

Asa

consequence,thespinalroutewillmostlikelybeabandoned（因此最好放弃在腰麻中使用）;however,somepromise

hasbeennotedwiththe

epiduralroute（可以尝试使用硬膜外路径）WhatAdjuvantMedicationsshouldbeused?

Clonidine（可乐定）,inspinalandepiduraldosesvaryingfrom15-50μgand50-120μg,respectively,canprolonganalgesia

anddecreaseshivering（无论腰麻或硬膜外，都可以延长镇痛，较少寒战）;However,mildhypotensionandsedationarenotinfrequentsideeffects（可能出现不常见的轻微低血压和催眠）.

Currently

clonidinehasonlyonespecificneuraxialindication(intractablecancerpain，只有一种适应证即顽固性癌痛),FDAwarningthat

“epiduralclonidine（硬膜外可乐定）

isnotrecommendedforobstetrical,postpartum,andperioperativepainmanagement”（不建议使用于分娩、产后及围手术期镇痛）.

WhatAdjuvantMedicationsshouldbeused?

Preservativefreemorphinesulfate（盐酸吗啡）

can

provide17-27hofpost-cesareananalgesia（17-27小时的产后镇痛）.Intrathecally（蛛网膜下腔给药）,acomparisonof0.025,0.05,0.1,0.2,0.3,0.4,and0.5mgdosesobservedthat0.1mgproducedanalgesiacomparabletodosesashighas0.5mg（0.1mg与高达0.5mg的效果无异）.

Theincidenceofpruritus,butnotnauseaandvomiting,appeareddoserelated（瘙痒症与剂量相关，但恶心呕吐与剂量不相关）.

Intheepiduralspace（硬膜外）,a

comparisonof1.25,2.5,3.75,and5mgdosesobservedthatthequalityofpost-cesareananalgesiadidnotimprove

beyond3.75mg（镇痛效果在达到3.75mg后就不再变化）.Pruritus,nauseaandvomitingdidnotappeardoserelated.WhatAdjuvantMedicationsshouldbeused?

Extended-releaseepiduralmorphine(缓释吗啡，商品名Depodur)canprovideanalgesiafor48hrswith10and15mgdoses;However,cautionshouldbeappliedtodosing

theepiduralcatheter

withlocalanestheticimmediatelyaftertheDepodur（硬膜外导管给予缓释吗啡后立刻给予局麻药时应该小心）,andevenupto1hourbefore,asthe

maximumplasmaconcentrationsofmorphinewillbehigher（即使是1小时前给予的吗啡，局麻药会升高吗啡的血浆峰值浓度）.DoesaPerfectCocktailExist（最佳药物组合）?

Themostrecentevidencewouldsuggestthefollowingcombinationsareoptimal:MedicationSpinalEpiduralLocalAnestheticBupivacaine

9-12mg2%Lidocaine+Bicarb8.4%(10mL/1mLratio)Fentanyl15-35μg50-100μgMorphine0.1mg3.75mgASSOCIATEDANESTHETICCONCERNSDURINGCESAREANDELIVERY（剖宫产麻醉相关问题）AntibioticUseandTiming

（抗生素使用）

Postpartuminfectionis5to20-foldgreaterinthosepatientsdeliveringbycesareanversusvaginalroutes（剖宫产的产后感染比自然分娩高5-20倍）

and

remainswithinthetopfivecausesofpregnancy-relatedmortality（产后五大死亡原因之一）.

Thetraditionalpracticeofadministering

antibioticsafterinfantdeliveryandumbilicalcordclampingoriginatedtopreventfetalexposuretoantibiotics（传统的使用方法是胎儿娩出、脐带夹闭之后，为了避免胎儿接触到抗生素）.

However,recentstudiesofantibioticusepriortocesareanskinincision（切皮前）

haveobservedsignificantlyfewermaternalinfections（观察到产妇感染的显著减少）

withnodifferencesinthefrequencyofneonatalsepsiswork-upsorprovensepsiscases（胎儿脓毒血症检验结果无差异）

OxytocinandUterotonicAgentUse（缩宫素使用）

Thecurrentguidelinesfortheadministrationof

oxytocinduringcesareandeliveryarediverse,

empiric,andvague,withnonevidence-baseddosesof20-40IUbeingadvocated（目前的缩宫素使用并没有循证支持）.

However,adequateuterinecontractions（足够的子宫收缩）

duringelectivecesareandeliveriesinnon-laboringwomen(未进入产程的孕妇）

requireonlysmallloadingdosesofoxytocin（只需要少量的缩宫素负荷量）(ED90=0.35IU);asimilarlylowloadingdose(ED90=2.99IU)isrequiredinlaboringwomen（产程中的孕妇）.OxytocinandUterotonicAgentUse

Consequently,aloweroxytocin,

hasbeenadvocated:OxytocinProtocolforCesareanDelivery:“RuleofThrees”3IUOxytocinIVLoadingDose(administeredbyrapidinfusion,ratherthanabolus,nofasterthan15seconds)3MinuteAssessmentIntervals（3分钟评估间隔）.Ifinadequateuterinetone,give3IUOxytocinIVrescuedose.3TotalDosesofOxytocin(InitialLoad+2RescueDoses)3IUOxytocinIVMaintenanceDose(3IU/Lat100mL/h)upto8hrs.3PharmacologicOptions(e.g.Ergonovine麦角新碱,carboprost卡前列素

andmisoprostol米索前列醇)ifinadequateuterinetonepersistsIntra-andPost-partumHemorrhage（产时产后出血）

Hemorrhageoccurringduringorfollowingcesareandeliveryisanincreasingcomplication（出血是日益增长的产时产后并发症）

thatisassociatedwith

significantmaternalmorbidityandmortality.

Theidentificationofriskfactorsassociatedwithuterineatony（发现子宫收缩乏力高危因素证据后需输血）requiringbloodt