AirwayEvaluationandManagementChapter6IntroductionThemajorresponsibilityoftheanesthesiologist:providingadequaterespirationforthepatients.Theairway-themostvitalelementinprovidingfunctionalrespirationNoanestheticissafeunlessmaintaininganintactfunctionalairway.Thesameprinciplesofairwaymanagementareapplicabletoallclinicalrespiratoryinadequacysituations.ContentsFactorsAffectingAirwayPatencyTechniquesofAirwayManagementTheDifficultAirwayTechniquesSection1

FactorsAffectingAirwayPatency1.AnatomyandPhysiologyTheairwayscanbedividedintopartsnamely:TheupperairwayMouthNosePharynxLarynxThelowerairwayTracheaBronchiPharynxExtendsfromtheposterioraspectofthenosedowntothecricoidcartilageDividedintothenasopharynx,theoropharynx,andthelaryngopharynx.LarynxLarynxatlevelofC-5inadults,atC-3innewbornUnpairedcartilageThyroidCricoidEpiglottisPairedCartilageArytenoidCorniculateCuneiformGlottisTheLowerAirway2.FactorsAffectingAirwayPatencyInclude:Secretions,blood,foreignbodyblockairway.GlossoptosisLaryngospasmBronchospasmNeuromusculardisease

GlossoptosisSymptomsandSignsInlessseverecases:Snore,thethroatwasdragged.Inseverecases:Abnormalchestbreathing,

threedepressionssignduringinspiration.SPO2decrease,cyanosis

Treatmentjawthrust,nasopharyngealairwayororopharyngealairway.Neckextension.Jawthrust,byplacingthefingersundertheanglesofthemandibleandliftingforward.Turningtheheadtooneside.InsertionofanoralairwayoranasalairwayAirwaypatencymayberestoredbythefollowing:LaryngospasmDefinition

LaryngospasmreferstoreflexclosureofthetruevocalcordsaloneorwiththefalsecordsbecauseofstimulationoftheintrinsiclaryngealmusclesSymptomsandSigns

Ahigh-pitchedsqueakysoundorstridor.Totalabsenceofsound,obstructedpatternofbreathing,unabletoventilate.Thehypoxia,hypercarbia,acidosisLaryngospasmIncentivesLaryngospasmcanresultfromthecombinationofreflexhyperactivityatanintermediatedepthofanesthesiaandnoxiousdistantsurgicalorlocalstimuli.Othersincludesecretions,vomitus,blood,inhalationofpungent

volatile

anesthetics,oropharyngealornasopharyngealairwayplacement,laryngoscopy,painfulperipheralstimuli,andperitonealtractionatalightdepthofanesthesia.TreatmentLessseverespasm:Deepeningtheanestheticlevelandremovingthestimuluswhileadministering100%oxygen.Moderatespasm:continuouspositivepressureontheairwaywithmaskandajawthrustmayrelievethespasm.Severespasm:useofmusclerelaxantssuchassuccinylcholine,endotrachealintubationifnecessary.Thelungsshouldbeventilatedwith100%oxygen,andeithertheanestheticlevelshouldbedeepenedbeforethenoxiousstimulationisresumedorthepatientmaybeallowedtoawakeniflaryngospasmhasoccurredduringemergenceLaryngospasmBronchospasmIncentivesAnaphylacticdrugsandbloodtransfusionreactions,secretionsandendotrachealintubationSymptomsandSignsWheezing(usuallymorepronouncedonexpiration)Tachypneaanddyspneaintheawakepatient,ordifficulttoventilateintheanesthetizedpatientSection2

TechniquesofAirwayManagementMethodsofAirwayManagementOrapharyngealairwayNasopharyngealairwayMaskventilationLaryngealmaskairwayEndotrachealintubation1.OrapharyngealairwayIndications

Jawthrustisinvalidforupperairwayobstruction.GlossoptosisofcomapatientsorsedativepatientsComplicationsNauseaorvomiting,coughing,laryngospasm,bronchospasm,anddentaltrauma.Thewrongsizeoralairwaymayworsenobstruction.Iftooshort,itmaycompressthetongue;iftoolong,itmaylieagainsttheepiglottis.OropharyngealAirway

(Bermanintubationairway)2.NasopharygealAirwayIndications

ThesameastheoropharyngealairwayAdvantages

BettertoleratedbyawakeorsedatedpatientsLesscausenauseaorvomiting,coughing,laryngosasm,bronchospasmEspeciallygoodforrestrictedopenningContraindications

AbnormalcoagulationThebasalskullfractureNasopharyngealcavityinfection

Nasalseptum

shift

NasopharygealAirwayNasopharygealAirwayIntubatingnasalairway3.MaskVentilationIndicationsToprovideinhalationanesthesiainpatientsnotatriskforregurgitationofgastriccontents.Topreoxygenate(denitrogenate)apatientbeforeendotrachealintubation.Toassistorcontrolventilationaspartofinitialresuscitation.TechniqueThemaskshouldfitsnuglyaroundthebridgeofthenose,cheeks,andmouthClearplasticmasksallowforobservationofThelipsforcolor(cyanosis)MouthforsecretionsorvomitusTechniqueforholdingthemask

withonehandwithtwohandsComplicationsThemaskmaycausepressureinjuriestosofttissuesaroundthemouth,mandible,eyes,ornose.Maskventilationdoesnotprotecttheairwayfromaspirationofgastriccontents.MaskVentilation4.LaryngealMaskAirway(LMA)ClassicLMASpecialLMAIntubatingLMAGastricLMAIndicationsAsanalternativetomaskventilationorendotrachealintubationforairwaymanagementinpatientswithoutriskofaspirationofgastriccontents(TheLMAisnotareplacementforendotrachealintubationwhenendotrachealintubationisindicated).Inthemanagementofaknownorunexpecteddifficultairway.Inairwaymanagementduringtheresuscitationofanunconsciouspatient.LMALMAContraindicationsPatientsatriskofaspirationofgastriccontents(emergencyuseisanexception).Patientswithmouthopeninglessthan2.5-3.0cm.Patientswithinfection,injury,hemangiomainthethroatPatientswithdecreasedrespiratorysystemcompliance,peakinspiratorypressuresshouldbemaintainedmorethan25cmH2OPatientsinwhomlong-termmechanicalventilatorysupportisanticipatedorrequired.Patientswithintactupperairwayreflexes,becauseinsertioncanprecipitatelaryngospasm.LMAAdverseeffectsThemostcommonadverseeffectissorethroatTheprimarymajoradverseeffectisaspiration.LaryngealedemaisuncommonStandardInsertionTechniqueFailureofLMAInsertionIndicationsforIntubationInadequateoxygenation(decreasedarterialPO2)thatisnotcorrectedbysupplementaloxygenviamask/nasalInadequateventilation(increasedarterialPCO2)NeedtocontrolandremovepulmonarysecretionsAnypatientincardiacarrest5.TrachealIntubationIndicationsforIntubationAnypatientindeepcomawhocannotprotecthisairway(Gagreflexabsent)Anypatientinimminentdangerofupperairwayobstruction(e.g.Burnsoftheupperairways)AnypatientwithdecreasedL.O.C,GCS≤8SevereheadandfacialinjurieswithcompromisedairwayIndicationsCont…AnypatientinrespiratoryarrestRespiratoryfailureHypoventilation/HypercarbiaPaCO2>55mmhgArterialhypoxemiarefractorytoO2PaO2<70mmhgon100%O2AdvantagesofEndotrachealIntubationCuffedE.TtubesprotecttheairwayfromaspirationE.TtubeprovidesaccesstothetracheobronchialtreeforsuctioningofsecretionsE.TtubedoesnotcausegastricdistentionandassociateddangerofregurgitationE.TtubemaintainsapatentairwayandassistsinavoidingfurtherobstructionE.TtubeenablesdeliveryofaerosolizedmedicationContraindicationsforIntubationPatientswithanintactgagreflexPatientslikelytoreactwithlaryngospasmtoanintubationattempt(e.g.Childrenwithepiglottitis)Basilarskullfracture–avoidnasotrachealintubationandnasogastric/pharyngealtubeComplicationsAssociatedWithIntubationTraumaoftheteeth,cords,arytenoidcartilages,larynxandrelatedstructures.Nasotrachealtubescandamagetheturbinates,causeepistaxis,andevenperforatethenasopharyngealmucosa.Hypertensionandtachycardiacanoccurfromtheintensestimulationofintubation;Thisispotentiallydangerousinthepatientwithcoronaryheartdisease.Transientcardiacarrhythmiasrelatedtovagalstimulationorsympatheticnervetrafficmayoccur.ComplicationsContinued…Damagetotheendotrachealtubecuff,resultinginacuffleakandpoorseal.Intubationoftheesophagus,resultingingastricdistentionandregurgitationuponattemptingventilation.Barotraumaresultingfromoverventilatingwithabagwithoutapressurereleasevalve(pneumothorax)ComplicationsContinued…Overstimulationofthelarynxresultinginlaryngospasm,causingacompleteairwayobstruction.Insertingthetubetodeepresultinginunilateralintubation(rightbronchus).Tubeobstructionduetoforeignmaterial,driedrespiratorysecretionand/orblood.EquipmentRequiredforSuccessfulIntubationEquipmentCont…LaryngoscopewithrelevantsizebladesMagillforcepsFlexibleintroducer10-20mlsyringeOropharangealairways–allsizesTapeETtubes–relevantsizesBite-blockBag-valve-maskwithoxygenconnectedSuctionunitwithYankauernozzleandendotrachealsuctioncatheterTechniqueofEndotrachealIntubationTechniqueofEndotrachealIntubationTechniqueCont…Positionthepatientsupine,opentheairwaywithahead-tiltchin-liftmaneuver.(Suspectedspinalinjury,attemptnaso-trachealintubation,spineinneutralposition.).Openmouthbyseparatingthelipsandpullingonupperjawwiththeindexfinger.Holdlaryngoscopeinlefthand,insertscopeintomouthwithbladedirectedtorighttonsil.Oncerighttonsilisreached,sweepthebladetothemidlinekeepingthetongueontheleft.TechniqueCont…Thisbringstheepiglottis

intoview.”DONOTLOOSESIGHTOFIT!”Advancethebladeuntilitreachestheanglebetweenthebaseofthetongueandepiglottis.(volecularspace)Liftthelaryngoscopeupwardsandawayfromthenose–towardsthechest.Thisshouldbringthevocalcordsintoview.Itmaybenecessaryforacolleaguetopressonthetracheatoimprovetheviewofthelarynx.PlacetheETTintherighthand.Keeptheconcavityofthetubefacingtherightsideofthemouth.Insertthetubewatchingitenterthroughthecords.TechniqueCont…Insertthetubejustsothecuffhaspassedthecordsandtheninflatethecuff.Listedforairentryatbothapicesandbothaxillaetoensurecorrectplacementusingastethoscope.RulesofIntubationAlwayshaveasuctionunitavailable.Anintubationattemptshouldneverexceed30seconds.Oxygenatethepatientpreandpostintubationwithabag-valve-mask.(100%O2).Havesedativemedicationavailableifneeded.(e.g.Midazolam15mg/3ml)Alwaysrechecktubeplacementmanuallyguidedbyoxygensaturationreadings.(Spo2).NasotrachealintubationIndications:Nasotrachealintubationmayberequiredinpatientsundergoinganintraoralprocedure.Contraindications:Basilarskullfractures,especiallyoftheethmoidbone,nasalfractures,epistaxis,nasalpolyps,coagulopathy,andplannedsystemicanticoagulationand/orthrombolysisComplications:Similartothosedescribedfororotrachealintubation.Additionally,epistaxis,submucosaldissection,anddislodgementofenlargedtonsilsandadenoidsmayoccur.Sinusitisandbacteremia.NasotrachealIntubationSection3

TheDifficultAirwayTechniquesTheDifficultAirway

TheASAdefinesadifficultairwayasfailuretointubatewithconventionallaryngoscopyafterthreeattemptsand/orfailuretointubatewithconventionallaryngoscopyformorethan10min.

DEFINITIONCATEGORIES

ThedifficultairwaycanbedividedintotherecognizeddifficultairwayandtheunrecognizeddifficultairwayThelatterpresentsthegreaterchallengefortheanesthesiologist.●Whatcanwedo?

“CannotIntubate,CannotVentilate”Mortality

50%～75%oftenoccursafterrepeatedunsuccessfulattemptsatintubationTheMostDangerousSituationEvaluationofDifficultAirwayPrioranestheticrecords

numberofintubationattemptsabilitytomaskventilatetypeoflaryngoscopebladeuseduseofstyletanyothermodificationsofintubationtechniqueSpecificsymptomsHoarsenessStridorWheezingDysphagiaDyspneaPositionalairwayobstructionEvaluationofDifficultAirwayDiseasesthatmayaffecttheairwayArthritisorcervicaldiskdisease——decreaseneckmobility→spinalcordinjuryInfectionsofthefloorofthemouth,salivaryglands,tonsils,orpharynx——causeedema,andtrismuswithlimitedmouthopeningTumors

——

obstructtheairway,causeextrinsiccompressionandtrachealdeviation

Morbidlyobese

Trauma

Previoussurgery,radia