高流量氧疗的生理效应培训课件

高流量氧疗的生理效应COIstatementTheauthorhasnoconflictof

interesttodeclare.2高流量氧疗的生理效应HighFlowaninterestingoxygenationmethod-novel-magic-gentleandmoderateSocool3高流量氧疗的生理效应HFNCshinesduringRSIPutthebigcannulaeintoyourpatient’snoseandlet’rrip.AddafacemaskorNIVorwhateveryourpreoxygenationpleasure,thenpushyourmedsandlaughtoyourselfasthesaturationrisesduringapnea.Whistlesweetlyastheinternilluminateseveryinchofthesoftpalatewithgreatdetermination.Hell,goseeanotherpatientandtellhimtocallyouwhenhe’sgivenup.Youremember,though,thedaysofthegiants.Whenbeingregardedasaskilledlaryngoscopistmeantsomething.Whentheword

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madeinternistsscatterlikemice.Whenitwasn’tsoeasytosavealife./2012/03/01/the-high-flow-nasal-cannula-in-the-emergency-department/4高流量氧疗的生理效应Pediatricianhaspromotedoxygentherapy1891­-E.BonnairedescribedO2inhalationsinthenewborn5高流量氧疗的生理效应Oxygentherapy&oxygendeliverydevicesHFNC6高流量氧疗的生理效应TheroleofHFNCinrespiratorytherapy7高流量氧疗的生理效应WhatisHFNC?a“new”methodsofoxygentherapyair/oxygenappliedtopatientathighflowratesair/oxygenrunthroughanasalcannulaair/oxygeniswellconditionedbysufficientwarmthandhumidification

--socalledheated,humidifiedhigh-flownasalcannula(HHHFNC)therapy2-70L/min8高流量氧疗的生理效应MechanismsofactionforHFNCWashoutofnasopharyngealdeadspaceReductionofinspiratoryresistance(workofbreathing)byprovidingadequateflowImprovedmechanicsbysupplyingadequatelywarmedandhumidifiedgasReductioninthemetaboliccostofgasconditioningProvisionofdistendingpressure9高流量氧疗的生理效应WashoutofnasopharyngealdeadspaceThehighvolumetricflowspouringfromasmallborecannulacausehighvelocityflowswhichcreateturbulentenergytoflushtheupperairwayofexpiratorygas.10高流量氧疗的生理效应Deadspacewashoutimprovesventilationanatomicaldeadspaceinadults≥30%oftidalvolumeinneonates≈50%oftidalvolumechangethegascompositioninnasopharyngealspacereducerebreathingexpiredCO2

increasethefractionofinspiredO2increasealveolarventilationefficiencyMV=

(VT–VD)xRR PaCO2=PeCO2/(1–VD/VT)PaO2=(PBO2–PH2O)xFiO2–PaCO2/R–PA-aO211高流量氧疗的生理效应Highflowandhighvelocityincreasealveolarventilationefficiencylikelyminimizetheinspiratoryresistanceassociatedwiththenasopharynxbyprovidingnasopharyngealgasflowsthatmatchorexceedapatient'speakinspiratoryflowCoandaeffectoccuringinthenasopharyngealregionduringexpirationpotentiallyassistexpiratoryeffortsbringaboutadecreaseinworkofbreathing

andrespiratoryratecreatemoreturbulentenergyformoreeffectivewashoutflushtheexpiratorygasfromtheupperairwayquicklyduringtheexhalationphaseofbreathing,whichiscriticalinpatientswithrapidbreathing13高流量氧疗的生理效应VentilatoryResponsestoHFNC

MündelTetal.MechanismsofnasalhighflowonventilationduringwakefulnessandsleepJApplPhysiol,2013.114:1058–106514高流量氧疗的生理效应MucociliarytransportsystemHealthciliatedepithelium Damagedciliatedepithelium/files/images/hospital/respiratory-care-continuum/full-width/mucociliary-disfunction-table/15高流量氧疗的生理效应MucosalfunctionsdependentoninspiredhumidityWilliams,RB.RespireCareClinNAm1998Jun;4(2):215-2816高流量氧疗的生理效应TemperatureandhumidityLowtemperaturedoesmeaninsufficienthumidity.Enoughwatersupplementdoesnotalwaysmeansufficienthumidity.Anadultmayrequireapproximately150calories/min(10kcal/h)forconditioninginspiratoryairfromambienttoBTS.KacmarekRM,etal.Egan'sFundamentalsofRespiratoryCare.St.Louis,MO:Elsevier/Mosby,2013.17高流量氧疗的生理效应InspiredgasneedsconditioningRespirationwithambientgas,notwarmedorhumidified,inducedbronchoconstrictionresponse,andresultedinasignificantdecreaseinbothpulmonarycompliance.ThenasalairpassagesexpendquiteafewenergytowarmandhumidityinspiratoryairfromambienttoBTS.Studiesfromthe1990'sdemonstratedthenegativeeffectsofusingnon-warmed,non-humidifiedgastosupportrespiration.18高流量氧疗的生理效应FlowandPressurefundamentalsHFNCisintendedtobeanopensystem,withflowdeliveredtoapatientvianasalcannula,wherethecannulaprongsdonotoccludethenaresandwherethepatient’smouthisnotheldclosed.Inthisopensystem,thepressureineachcompartmentisafunctionoftheresistor(s)thatlieinseriesdownstreamfromthatcompartment.Inthisregard,circuitpressureswillalwaysbesubstantiallygreaterthanpressureinthenasopharynx.19高流量氧疗的生理效应Factorsdeterminnasopharyngealpressuretheflowsettingthepatient’suniqueanatomicaldimensionstheleakoutofthenosearoundtheprongsandoutofthemouth(ODofcannulaprongvs.IDofnares)20高流量氧疗的生理效应MechanismsofAction:

HFNCDiffersfromCPAPMündelTetal.MechanismsofnasalhighflowonventilationduringwakefulnessandsleepJApplPhysiol,2013.114:1058–106521高流量氧疗的生理效应EffectsofflowonairwaypressureduringHFNCHigherflowratecreateshigherairwaypressure.Pressureisdifferentwhenmouthclosedoropen.Onlymoderatepositiveairwaypressure(<10cmH2O)canbegeneratedbyHFNC.ParkeR,etal.RespirCare2011;56(8):1151–1155.22高流量氧疗的生理效应PositiveairwaypressureisnottheprinciplemechanismofHFNCThebasicflowsettingismeantfundamentallytoexceednormalinspiratoryflowratessoastoeliminateentrainmentofroomair,andenhancenasopharyngealwashouteffects.Excessiveflowsinanattempttogeneratesubstantialdistendingpressuresshouldnotbeutilized.Toaccomplishtheactionsofdeadspacewashout,selectingnasalprongsshouldhaveanoutsidediameternomorethan50%oftheinsidediameterofthe