气道的评估和管理Airway-Evaluation-and-Management

AirwayEvaluationandManagement,II.EVALUATION,A.History.Ahistoryofdifficultairwaymanagementinthepastmaybethebestpredictorofachallengingairway.,1.Arthritisorcervicaldiskdiseasemaydecreaseneckmobility.2.Infectionsofthefloorofthemouth,salivaryglands,tonsils,orpharynxmaycausepain,edema,andtrismuswithlimitedmouthopening.3.Tumorsmayobstructtheairwayorcauseextrinsiccompressionandtrachealdeviation.4.Morbidobesityisassociatedwithdifficultairwaymanagement.,II.EVALUATION,5.Traumamaybeassociatedwithairwayinjuries,cervicalspineinjury,basilarskullfracture,orintracranialinjury.6.Previoussurgery,radiation,orburnsmayproducescarring,contractures,andlimitedtissuemobility.7.Acromegalymaycausemandibularhypertrophyandovergrowthandenlargementofthetongueandepiglottis.8.Sclerodermamayproduceskintightnessanddecreasemandibularmotionandnarrowtheoralaperture.,II.EVALUATION,9.Trisomy21patientsmayhaveatlantoaxialinstabilityandmacroglossia.10.Dwarfism.11.Othercongenitalanomaliesmaycomplicateairwaymanagement.B.PhysicalExamination1.Specificfindingsthatmayindicateadifficultairwayincludethefollowing:a.Inabilitytoopenthemouth.b.Poorcervicalspinemobility.c.Recedingchin(micrognathia).,II.EVALUATION,d.Largetongue(macroglossia).e.Prominentincisors.f.Shortmuscularneck.2.Injuriestotheface,neck,orchestmustbeevaluat-edtoassesstheircontributiontoairwaycompromise.3.Headandneckexamination.Thereisnosinglebestpredictorofdifficultairwaymanagementonthephysicalexam,soadetailedexamisinorder.,4.TheMallampaticlassification,Themodifiedclassificationincludesthefollowingfourcategories(Fig.13.1):a.ClassI.Faucialpillars,softpalate,anduvulaarevisible.b.ClassII.Faucialpillarsandsoftpalatemaybeseen,buttheuvulaismaskedbythebaseofthetongue.c.ClassIII.Onlysoftpalateisvisible.Intubationispredictedtobedifficult.d.ClassIV.Softpalateisnotvisible.Intubationispredictedtobedifficult.,III.MASKAIRWAY,A.Indications1.Topreoxygenate(denitrogenate)apatientbeforeendotrachealintubation.2.ToassistorcontrolventilationaspartofinitialresuscitationbeforeanETTisplaced.3.Toprovideinhalationanesthesiainpatientsnotatriskforregurgitationofgastriccontents.,2.Maskplacement.,withonehandwithtwohands,III.MASKAIRWAY,D.Complications.Themaskmaycausepressureinjuriestosofttissuesaroundthemouth,mandible,eyes,ornose.Lossoftheairwaymayresultfromlaryngospasmorvomiting.Maskventilationdoesnotprotecttheairwayfromaspirationofgastriccontents.Laryngospasm,atoniccontractionofthelaryngealandpharyngealmuscles,causesairwayobstructionthatmayberelievedbyjawthrustandtheapplica-tionofconstantpositiveairwaypressure.Ifthisfails,asmalldoseofsuccinylcholine(20mgintravenouslyorintramuscularlyintheadult)mayberequired.,IV.LARYNGEALMASKAIRWAY,1.Indicationsa.Asanalternativetomaskventilationorendo-trachealintubationforairwaymanagement.TheLMAisnotareplacementforendotrachealintubationwhenendotrachealintubationisindicated.b.Inthemanagementofaknownorunexpecteddifficultairway.c.Inairwaymanagementduringtheresuscitationofanunconsciouspatient.,LMAInsertion,2.Contraindicationsa.Patientsatriskofaspirationofgastriccontents(emergencyuseisanexception).b.Patientswithdecreasedrespiratorysystemcompliance,becausethelow-pressuresealoftheLMAcuffwillleakathighinspiratorypressuresandgastricinsufflationmayoccur.Peakinspiratorypressuresshouldbemaintainedatlessthan20cmH2Otominimizecuffleaksandgastricinsufflation.c.Patientsinwhomlong-termmechanicalventilatorysupportisanticipatedorrequired.d.Patientswithintactupperairwayreflexes,becauseinsertioncanprecipitatelaryngospasm.,V.ENDOTRACHEALINTUBATION,A.OrotrachealIntubation1.Indications.Endotrachealintubationisrequiredtoprovideapatentairwaywhenpatientsareatriskforaspiration,whenairwaymaintenancebymaskisdifficult,andforprolongedcontrolledventilation.Intubationalsomayberequiredforspecificsurgicalprocedures(e.g.,head/neck,intrathoracic,orintra-abdominalprocedures).,V.ENDOTRACHEALINTUBATION,3.Complicationsoforotrachealintubationincludeinuryofthelipsortongue,teeth,pharynx,ortrachealmucosa.Theremayrarelybeavulsionofarytenoidcartilagesordamagetovocalcordsortrachea.,B.NasotrachealIntubation1.Indications.Nasotrachealintubationmayberequiredinpatientsundergoinganintraoral,V.ENDOTRACHEALINTUBATION,procedure.ComparedwithoralETTs,themaximaldiameterthatcanbeaccommodatedisusuallysmaller,and,accordingly,theresistancetobreathingmaybehigher.Thenasotrachealrouteisnowrarelyusedforlong-termintubationbecauseofincreasedairwayresistanceandtheincreasedriskofsinusitis.,VI.THEDIFFICULTAIRWAYANDEMERGENCYAIRWAYTECHNIQUES,2.TheASAdefinesadifficultairwayasfailuretointubatewithconventionallaryngoscopyafterthreeattemptsand/orfailuretointubatewithconven-tionallaryngoscopyformorethan10minutes.Othershavesuggestedthatamoreappropriatedefinitionofadifficultairwaywouldbethatoffailuretointubatewithconventionallaryngoscopyafteranoptimal/bestattempt.,3.Theuseofregionalanesthesiaasawaytoavoidtheknownoranticipateddifficultairwaydeservesspecialmention.4.TheLMA(ClassicandFastrach)isaprominentairwayoptionthroughoutthe2003ASAdifficultairwayalgorithm.,B.EmergencyAirwayTechniques,1.Percutaneousneedlecricothyroidotomy2.Rigidbronchoscopy3.Cricothyroidotomy4.Tracheostomy,CaseReport,A48-yr-old,58-kg,womanwasscheduledforcraniotomybecauseofatumoraroundthethirdventricle.-Afterinductionofanesthesia,nasotrachealintubationwitha6.5cuffed-ETT(endotrachealtube)wasperformedwithoutdifficultyunderdirectlaryngoscopy.-ThepositionoftheETTwasconfirmedandwellsecuredoverherrightnostrilatthe26-cmmark.,Sevenhoursafterinduction,however,theend-tidalcarbondioxidetracingdisappearedsuddenlyandtheventilatorapneapressurealarmwasactivated.TheETTwasthennotedtobedislodgedoutofthepatientsrightnostril.,AfterconfirmingETTextubation,thesurgicalmicroscopewasmovedfromtheoperatingtableandasteriletowelwasimmediatelyplacedoverthepatientsopeneddura.,ManualventilationofthelungswasattemptedviaafacemaskHowever,thiswasdifficultbecauseupperairwayobstructionandthepronepositionwithneckflexed.Itwasalsodifficulttodepressthechinforintroductionofanoropharyngealairway.,Nasalfiberopticbronchoscopy(FOB)wasattemptedwiththeoperatorundertheoperatingtable,whichwasdifficultanduncomfortablebecauselimitedspaceforcedtheoperatortolieonthefloortoperformFOB.TheoperatingtablewasthenelevatedwithreverseTrendelenburgpositionandleft-sidetilt.TheoperatorthenhadenoughspacetoperformFOBbysittingonthefloor,UnderFOB,thepatientsedematouslarynxandvocalcordwerevisible.Aftervisualizingthecarina,theoperatoradvancedtheETTalongwiththefiberopticbronchoscopethroughherrightnostril.Thetubepositionwasconfirmedbydirectvisualizationandcapnography.Theairwaywasreestablishedin6min.,Duringtheprocessofemergencyairwaymanagement,acontinuoushighflowofoxygenwasgivenviafacemaskandthesuctionportofthefiberopticbronchoscopeTherewasneitherarterialdesaturationnorhemodynamicdisturbance.,DISCUSSION,-Wed