临床麻醉学英文版Word格式.docx

临床麻醉学英文版Word格式.docx

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Basictechniques,37Thelaryngealmaskairway,42Emergencyairway

Simpleadjuncts,39Trachealintubation,43techniques,50

Maintenanceofapatentairwayisanessentialprerequisiteforthesafeandsuccessfulconductofanesthesia.Inaddition,duringresuscitationpatientsoftenhaveanobstructedairwayeitherasthecauseorresultoftheirlossofconsciousness.Theskillofairwaymaintenanceshouldbeacquiredbyalldoctors,andnotsimplyregardedastheresponsibilityoftheanesthetist.Thedescriptionsofairwaymanagementtechniques,whichfollow,areintendedtosupplementpracticeeitheronamanikinorpreferablyonandanesthetizedpatientunderthedirectionofaskilledanesthetist.

Basictechniques

Anesthesiafrequentlyresultsinlossoftheairwayanditismosteasilyrestoredbyacombinationoftheheadtiltalongwithajawthrust（seeChapter2）.Thelatterisprovidedbytheanesthetist’sfourthandfifthfingers（ofoneorbothhands）liftingtheangleofthemandible.Theoveralleffectdesiredisthatthepatient’smandibleis‘lifted’intothemaskratherthanthemaskbeingpushedintotheface（Fig.3.1）.

FACEMASKS

●ThemostcommonlyusedtypeinadultsistheBOCanatomicalfacemask（Fig.3.2）whichisdesignedtofitthecontoursofthefacewiththeminimumofpressure.

●Leakageofanestheticgasesisminimizedbyanair-filledcuffaroundtheedge.

●Masksatemadeinavarietyofsizesandthesmallestone,whichprovidesagoodseal,shouldbeused（tominimizetheincreaseindeadspace,whichoccurs）.

●TheAmbumask（Fig.3.2）hasatransparentbody—allowingidentificationofvomit–makingitpoplarforresuscitation.

●Allmasksmustbedisinfectedbetweeneachpatient.

Simpleadjuncts

Themostcommonlyandusedaretheoropharyngeal（Guedel）andnasopharyngealairways,insertedaftertheinductionofanesthesiatohelpmaintaintheairwayinconjunctionwiththetechniquesdescribedabove.

OROPHARYNGEALAIRWAY

●Thesearecurvedplastictubes,flattenedincross-sectionandflangedattheoralend,whichlieoverthetongue,preventingitfromfallingbackintothepharynx.

●Theyareavailableinavarietyofsizesfromneonatestolargeadults.Thecommonestsizesare2-4,forsmalltolargeadults,respectively.

●Aguidetothecorrectsizeisdeterminedbycomparingtheairwaylengthtotheverticaldistancefromthecornerofthepatient’smouthtotheangleofthemandible.

●Itisinitiallyinserted‘upsidedown’asfarasthebackofthehardpalate（Fig.3.3a）,rotated180（Fig.3.3b）andfullyinsertedutiltheflangeliesinfrontoftheteethorgumsinanedentulouspatient（Fig.3.3c）.

NASOPHARYNGEALAIRWAY

●Theseareround,malleableplastictubes,beveledatthepharyngealendandflangedatthenasalend.

●Theyaresizedontheirinternaldiameterinmillimeters,withlengthincreasingwithdiameter.Thecommonsizesinadultsare6-8mm,forsmalltolargeadults,respectively.

●Aguidetothecorrectsizeismadebycomparingthediametertotheexternalnaris.

●Priortoinsertion,thepatencyofthenostril（usuallytheright）shouldbecheckedandtheairwaylubricated.

●Theairwayisinsertedalongthefloorofthenose,withthebevelfacingmediallytoavoidcatchingtheturbinates（Fig.3.4）.

●Asafetypinmaybeinsertedthroughtheflangetopreventinhalationoftheairway.

●Ifobstructionisencountered,forceshouldnotbeusedasseverebleedingmaybeprovoked.Instead,theothernostrilcanbetried.

PROBLEMSWITHAIRWAYS

Thepresenceofsnoring,indrawingofthesupraclavicular,suprasternalandintercastalspaces,useoftheaccessorymusclesorparadoxicalrespiratorymovement（see-sawrespiration）suggestthattheabovemethodsatefailingtomaintainapatentairway.Commonproblemsarisingusingthesetechniquesalongwithafacemaskduringanesthesiaare:

1inabilitytomaintainagoodsealbetweenthepatient’sfaceandthemask,particularlyinthosewithoutteeth;

2fatigue,whenholdingthemaskforprolongedperiods;

3theriskofaspiration,duetothelossofupperairwayreflexes;

4theanesthetistisnotfreetodealwithanyotherproblems,whichmayarise.

Thelaryngealmaskairway（LMA）ortrachealintubationmaybeusedtoovercometheseproblems.

Thelaryngealmaskairway

Thisdevicewasdesignedforuseinspontaneouslybreathingpatients.Itconsistsofa‘mask’,whichsitsoverthelaryngealopening,attachedtowhichisatube,whichprotrudesfromthemouthandconnectsdirectlytotheanestheticbreathingsystem.Ontheperimeterofthemaskisaninflatablecuff,whichcreatesasealandhelpstostabilizeit.TheLMAisproducedinavarietyofsizessuitableforallpatients,fromneonatestoadults,withsizes3and4beingthemostcommonlyusedinfemaleandmaleadults,respectively.Positivepressur