钟泰迪 气道管理-华东六省课件

胃管和气道管理

（Gastrictubesandairwaymanagement）

钟泰迪存在的问题(为什么讲课)？饱胃病人常采用快诱导麻醉插管技术而这些容易误吸的病人术前常放置胃管是否诱导前必须，没有统一的临床指导规则也没有统一的意见是否诱导前将胃管放在原处，撤到食道，或排除讲课内容1.快诱导麻醉插管技术2.胃管放置的历史和现状3.环状软骨按压技术4.特殊高危误吸病人的一般处理由于橡胶胃管插入困难，容易堵塞，一些病人发生过敏，1950s发展了塑料胃管聚乙烯（polyethylene）,Polyvinyland硅树脂（silicone）

聚氨酯（polyurethane）

Salem-Sump胃管，1960s，双腔:adrainagelumenandasmallersecondarylumenthatisopentotheatmospheretoallowairtobedrawnintothestomachandpreventthesuctionsealeffectongastricmucosaduringsuctioning

目前有不同长度，不同官腔大小，不同用度和特殊用途的胃管胃管含有有利于定位的不透X线的线条14-20F用于成人，婴幼儿采用小型号32-36F大型胃管用于病理性肥胖腔镜下胃折叠手术是否经鼻或经口插入决定于下列因素：尽用于术中，还是整个围手术期。

病人是清醒的还是无意识的是气管插管前放置胃管是否存在创伤后鼻咽部损伤胃管的大小以及每一途径的相对风险也必须考虑

放置胃管的适应症主要为诊断和治疗诊断方面：发现胃肠道出血测试消化道食物中毒取得胃内培养标本测定胃内pH和胃容量监测胃肠引流情况

围手术期放置胃管通常目的排除胃食道内容物减少误吸风险减轻术后呕吐

预防和治疗术后胃扩张，麻痹性肠梗阻

缓解肠梗阻症状避免腔镜手术时胃损伤改善通气

从1930s开始一直认为胃肠术后胃扩张导致肺误吸，切口裂开，吻合口漏，因此腹部手术病人常规置胃管进行胃肠减压。WilliamW.Mayooncewrote“it

ismoreimportantforasurgeontocarryanasogastrictubethanastethoscopeinhispocket”

放置胃管的并发症咳嗽呕吐引起的血动学改变肺误吸打结：气管导管周围，会厌部，引起气道梗阻气管支气管出血—低氧血症溃疡穿孔置入颅内和中耳损伤眼动脉Pre-SellickEra（环状软骨按压技术之前）在1961年环状软骨按压技术采用之前，避免误吸采用：神经阻滞，如硬麻，腰麻清醒插管全麻诱导时头高位40度腰麻，硬麻缺点：

平面过高的腰麻，硬麻不能预防误吸的发生，如果过度镇静风险更大交感神经阻滞后胃肠蠕动加强平面过高时的通气不足，需要辅助呼吸“清醒插管”无论经鼻或经口都要有熟练的操作技术，良好表面麻醉，合适的镇静深度。否则操作困难，口鼻出血，血动学波动等并发症

关于头高位40度1951年首次由MortonandWylie与现在采用的快诱导插管不同点只是环状软骨按压麻醉和肌松情况下胃内压力18cmH2O而头高位40度时成人咽喉部高于胃食道链接处19cm，因此理论上在此体位下，哪怕胃内容物进入食道也不会到达咽喉部由于肠梗阻病人胃内排空后会持续充盈，因此麻醉诱导期间通常使用胃管减压诱导期留置胃管后确实消除了由呕吐返流引发的并发症因此急诊除分娩外常规术前放置胃管

用过带套囊胃管在胃食道链接处充气预防返流，但要做到密闭的充气压力而不损伤食道是不容易的环状软骨按压技术（TheCricoidPressureManeuver）In1961,SellickintroducedCP“tocontrolregurgitationofgastricoresophagealcontentsuntilintubationwithacuffedendotrachealtubewascompleted.”,Sellick当时通过充满造影剂的软乳胶膨胀导管，在颈5平面以10cmH2O压力进行环状软骨按压，证明阻塞了食道腔。由于Sellick’技术为高危误吸病人所设计，因此好多病人麻醉诱导前已经留置了胃管并且留置了胃管反而使食道上、下端括约肌收缩受影响，增加了返流的风险

Post-SellickEra

Sellick’s技术迅速成为快诱导插管技术的一部分在CP的新RSII不仅适合于急诊、产科和危重医学也对有高危误吸的择期成人和儿科病人。CP的广泛接受是由于克服了头高位的缺点

第一,胃内压（IGPs）高于20cmH2O在胃扩张病人常见,头高位40°并不能完全预防胃食道内容到达第二,一当头高位期间胃内容到达咽喉处，误吸很可能发生。第三,低血容量病人头高位是不利的.

第四,由于小儿食道短，头高位40°时咽喉的高度没有达到克服胃食道连接处的胃内压

过去的几十年临床医师对CP的有效性和必要性提出了疑问。疑问主要是：(a)数据和效果主要从死体上得到，因此缺乏科学依据。(b)食道并不是恰好位于CC的正后方，因此,由CP产生的中线食道上端压迫并不可靠(c)CP引起食道下端括约肌反射性松弛(d)虽然应用了CP，但仍然有肺误吸的报道(e)CP触发恶心呕吐，甚至极少数食道破裂;(f)CP使气管插管，面罩通气和LMA放置困难

在Sellick原来的研究中使用的是只要轻微按压就能阻塞的软乳胶管,但后来使用的是聚氨酯制成的硬胃管，很难用CP压力阻塞小儿和成人研究证实了CP对胃管周围的封闭是有效的.

这些发现建议麻醉诱导前不需要拔除胃管。对突然增加的胃内压可以开放胃管释放胃内容，而CP预防胃内容到达咽喉处CPIn1993,VannerandPryle假设CC30N的力应用于CC10cm2区域将产生200mmHg的压力(30,000N/m2=30kPa).

但实际发现30N的力，在胃内压超过40mmHg时，食道内液体仍然有返流.可能的解释是对CC产生的压力并不是均匀分布的，有些区域的压力低于40mmHg.

在放置胃管病人，CP应用前后采用CT对CC区域进行扫描发现：当CC结构压迫颈椎体一起时，食道腔的部分被压扁。轻轻侧旋CC结构腔道的其余部分压到椎体侧面的颈长肌上NGT被挤到官腔压迫相对较小的腔的侧面.

这提示CP压迫期间，NGT不但不影响CP对食道上端的压迫，实际反而能改善作用死体研究也证实放置胃管反而增加ICP的效果不管上述有效的证据，Sellick’早期麻醉诱导前将胃管拔除的观点仍然受到一定的重视“胃管的存在影响食道括约肌收缩，是返流的基础”

特殊高危误吸病人的一般处理

高危误吸麻醉诱导前最大可能的吸氧使病人氧合达到最佳状态。大部分病人在充分给氧的情况下，3分钟左右深呼吸就可以达到最大氧合。胃管留置病人可能使面罩和脸之间漏气氧合最少》90%

可能困难插管，困难通气病人，氧合时间延长（》10分钟）插管期间可通过鼻导管、口腔或环甲膜穿刺给氧纤支镜插管病人也可经面罩，鼻导管，口腔导管给氧

也可通过纤支镜通道给氧对于气道狭窄病人，纤支镜通过狭窄部位会堵塞气道加重缺氧。低血容量病人适当补液昏迷病人用药根据实际情况

高血压病人必须采取适当技术缓解气管插管刺激血液动力学反应预测到困难气道的病人纤支镜技术优于RSII颈椎不稳定病人纤支镜CP禁忌情况：咽喉壁脓肿食道上端异物咽喉部创伤颈椎损伤

谢谢!SpecificMeasures

EsophagealLesions

Zenkerdiverticulum(咽下部)isanoutpouchingofthemucosa,whichdevelopsintheweakarea(Killiandehiscence裂开)betweenthethyropharyngeusandcricopharyngeusmusclesCompressibleswellingdevelopsasthesacenlarges.Regurgitationofmaterialfromthepouchmayoccurduringanestheticinduction,intubation,orevenafterintubationduetoseepageoffluidaroundthetrachealtubecuffduring

surgicalmanipulation.

Regurgitationofmaterialfromthepouchmayoccurduringanestheticinduction,intubation,orevenafterintubationduetoseepageoffluidaroundthetrachealtubecuffduringsurgicalmanipulation.Emptyingofthepouchbythepatientexertingexternalpressurebeforeanestheticinductionisencouraged

TheeffectivenessofCPdependsonthelocationofthebodyofthesacinrelationtotheCC.Ifthesacissmall,thebodyofthepouchwillbeattheleveloftheCC;insuchacase,CPwillcompressthebodyofthepouch,spillingthecontentsintothepharynx.Ifthesacislarge,theneckofthepouchwillbeposteriortotheCC,andCPwillnotemptythecontentsofthepouchintothepharynx

ReviewofthebariumswallowishelpfulindeterminingwhetherCPshouldbeusedifRSIIischosen

Variousanestheticregimensincludingregionalanesthesia,awaketrachealintubation,andRSIIwithCPorheaduptilthavebeenusedsuccessfullyforsurgicalrepairofthe

diverticulum.Deepandsuperficialcervicalplexusblocks

withoutcomplicationshavebeenreportedinaseriesof58patients.

Regardlessoftheanestheticchoice,straining,gagging,orcoughingshouldbeavoidedbecausetheymaycauseexternalpressuretothepouchandprovokeregurgitation.Thetrachealtubecuffshouldbeimmediatelyinflatedsoastopreventseepageoffluidaroundthecuff.InsertionofaGTshouldbeavoidedbecauseitcancauseperforationofthediverticulum.IfplacementofaGTisnecessary,cautionmustbeexercised.

Achalasia（喷门失弛缓症）isanidiopathicdisorderoftheesophaguscharacterizedbyimpairedrelaxationoftheLESandesophagealaperistalsis（蠕动停止）resultinginesophagealdilation,andretentionofundigestedfoodmixedwithair.Foodparticlesmayremaininthedilatedesophagusformanyhoursordaysregardlessofthedurationoffasting.

Thiscanresultinregurgitation,aspiration,respiratoryinfections,upperrespiratoryobstruction,trachealcompression,andsuddenobstructionofthetrachealtubeduringanesthesia.TreatmentsincludeendoscopicpneumaticdilationoftheLES,surgicalmyomectomy,andbotulinumtoxin（肉毒素）injection.

NitratescancausetransientrelaxationoftheLESanddecompressionoftheesophagealdilation.Removalofmaterialfromthedilatedesophagusbyawide-boreorogastrictubemayleadtopromptresolutionofsymptoms

Theinsertionofalarge-boreorogastrictubeisadvisablebeforeproceedingwiththeanesthetic,evenifitmaynotbecompletelyeffectiveinremovingallfoodparticles.AlthoughwehaveusedRSIIinpatientswithachalasia,awakeintubationmaybepreferableinseverecases

GastroesophagealReflux

Forpulmonaryaspirationtooccur,gastriccontentsmustflowtotheesophagus(GEreflux),thecontentsmustreachthepharynx(esophagopharyngealreflux),andthelaryngealreflexesmustbeobtunded.

Twolinesofdefensepreventgastriccontentsfromreachingthepharynx,thefirstattheGEjunction,andthesecondattheupperesophagealsphincter(UES)Normally,theIGPis10to15cmH2O

higherthantheesophagealpressure,whichissubjectedtothenegativeintrathoracicpressure

Iftherewerenomechanismtoclosethelumenbetweenthe2cavities,GErefluxwouldreadilyoccur,especiallyiffavoredbygravity.Various“antireflux”mechanismshavebeenproposed,themostimportantisthetoneoftheLES,whichmaintainsapressurehigherthantheIGP

ItisthedifferencebetweentheLESpressureandtheIGP,“thebarrierpressure,”that

determineswhetherregurgitationwilloccurAnincreaseinIGPoradecreaseinLEStonewillfacilitateGErefluxTheIGPcanincreasesecondarytoanincreaseinintraabdominalpressureorwhenthenormalcapacityofthestomach(1.0–1.5Linadults),whichisdeterminedbythecompliance

ofthestomachandbythecapacityoftheabdominalcavitytoaccommodatetheincreasedvolume,isexceeded

ThetoneoftheLESisinfluencedbyneural,hormonal,pharmacologic,andpathologicfactors.84–87AnincreaseinIGP(or

intraabdominalpressure)isgenerallyaccompaniedbyanincreaseinLESpressure.This“adaptive”increaseinLEStoneoccurswithincreasesinabdominalpressuresupto30

cmH2O,andinnormalindividualstypicallyoccurswithsuccinylcholine-inducedfasciculations.

Becausesuccinylcholine-inducedincreasesinIGPareaccompaniedbydisproportionateincreasesinLESpressure,GErefluxnormally

doesnotoccur.However,thisphenomenonmaybeabsentinsomepatientswithGErefluxandgastricdistension

Inthesesituations,afurtherincreaseinIGPmaypromoteGEreflux.InpatientswithsymptomsofGErefluxandsymptomatichiatushernia(食管裂孔疝),dysfunctionoftheLESresultsina

lowerbarrierpressure,allowingflowofgastriccontentsintotheesophagusPharmacologicapproachestopromote

gastricemptying,increasebarrierpressure,anddecreaseorneutralizegastricacidityhavegainedpopularityinthepreanestheticmanagementofpatientswithGEreflux.Thereaderisreferredtoothersourcesformoreinformationonthissubject.ThevalueofroutineuseofGTsinpatientswith

GErefluxhasnotbeenaddressedintheliterature.

CertainanestheticcomplicationsormaneuverscaninduceGEoresophagopharyngealreflux.AirwayobstructionmaycauseGErefluxbyincreasingthepleuroperitonealpressuredifferenceduringstrongrespiratoryefforts

andbyincreasingtheIGPduetooveractionofthediaphragm

Positivepressureventilation(inexcessof20

cmH2O)beforetrachealintubationmayleadtointermittentopeningoftheUESandLES,resultingingastricinsufflationandasubsequentincreaseinIGPNormally,theUEStonecreatesasphinctericpressureofabout38mmHginawakesubjects

Thistoneismarkedlydecreasedbymusclerelaxantsandinductiondrugs,withtheexceptionofketamine.RelaxationoftheUESoritsmechanicalstretchingduringintubationcanfacilitatetheflowofesophagealcontents,ifpresent,tothepharynx.IthasbeensuggestedthatCPsubstitutesforthelossoftheUEStone,whichaccompaniesanestheticinductionandmusclerelaxation.

GastricDistensionGIobstructioncanbemechanicalasinpyloricstenosisorfunctionalasinileuscausedbyperitonitisortrauma.Regardlessofthecause,GIobstructionultimatelyleadstogastricdistension,whichcancauseanincreasedIGP,GEreflux,andvomiting.

ThedecisiontoinsertanNGT

beforeanestheticinductiondependsonthedegreeofdistension.Assessmentofthedegreeofgastricdistensionandbowelobstructioncanbemadefromtheclinicalandimagingfindings.

Bedsideultrasonographicassessmentofthegastricantrumandbodycanprovidequantitativeinformationaboutthevolumeofthegastriccontentsaswellasqualitativeinformationregardingitsnature(gas,fluid,orsolid).Anestimatedvolumeinexcessof200to

300mLinadultssuggeststhepresenceofseveredistensionandservesasanindicationforplacementofanNGTbeforeanestheticinduction.

InvestigatorshavearguedaboutwhethergastriccontentscanberemovedcompletelywithaGT.SomeinvestigatorsreportedthatthevolumeremovedviaaGTunderestimatesthetruevolumeofgastriccontents.

Othersdemonstratedthatthismethodisaveryreliableestimateofthetotalvolumeofgastriccontents.Obviously,manyfactorsinfluencethesuccessofblindgastricemptying.Theseincludesize,type,andpatencyoftheGTanditscorrectplacement,positionofthepatient,useofexternalabdominalpressure,andconsistencyofcontents.

Theuseofamultiorifice,vented,large(18F)GTismoreeffectivethantheuseofa

nonventedGT.Multipledistalopeningsensurethatnearly

allgastricpouchesaredrained.Evenifgastricsuctioningdoesnotguaranteecompleteemptying,itreducestheIGP,

andtheresidualvolumebecomesclinicallyinsignificantasanaspirationrisk

ManymeasureshavebeenproposedtofacilitateproperGTplacement,theapplicationofwhichdependsonwhetherthepatientisawakeoranesthetizedandwhethertheGT

i