Noninvasiveventilation

Overview

Definition Types Advantages&disadvantages Indications&contraindications Interface ModesofNIV Guidelinesforinitiation&termination Complications Conclusion

Definition

Noninvasiveventilation(NIV)referstothedeliveryofmechanicalventilationtothelungsusingtechniquesthatdonotrequireaninvasiveartificialairway(ETT,TT)

TypesofNIV

NegativepressureNIV MainmeansofNIVduringthe1sthalfofthe20thcentury

Extensivelyusedduringpolioepidemics

Tankventilatorironlung

Cuirass,Jacketventilator,Hayekoscillator

PositivepressureNIV Positivepressuredeliveredthroughmaskcase

CPAP&BiPAP

NegativePressureVentilation(NPV)

Negativepressureventilatorsapplyanegativepressureintermittentlyaroundthepatientsbodyorchestwall

Thepatientshead(upperairway)isexposedtoroomair

Negativepressureisappliedintermittentlytothethoracicarearesultinginapressuredroparoundthethorax

Thisnegativepressureistransmittedtothepleuralspaceandalveolicreatingapressuregradientbetweentheinsideofthelungsandthemouth

NegativePressureVentilation(NPV)

NIV Advantages

Noninvasiveness Flexibilityininitiatingandremovingmechanicalventilation

Allowsintermittentapplication Improvespatientcomfort Reducestheneedforsedation Oralpatency

Preservesspeech,swallowingandexpectoration,reducestheneedfornagastric tubes

Advantages

Avoidtheresistiveworkimposedbytheendotrachealtube

Avoidsthecomplicationsofendotrachealintubation Early(localtrauma,aspiration) Late(injurytohypopharynx,larynx,andtrachea,nosocomialinfections)

Reducesinfectiouscomplications pneumonia,sinusitis,sepsis

Lesscost

Mechanismofaction

Reductionininspiratorymuscleworkandavoidanceofrespiratorymusclefatigue

Tidalvolumeisincreased CPAPcounterbalancestheinspiratorythresholdworkrelatedtointrinsicPEEP.

NIVimprovesrespiratorysystemcompliancebyreversingmicroatelectasis ofthelung

Enhancedcardiovascularfunction Afterloadreductiond/tincreasedintrathoracicpressure

Pathophysiologyofacutehypercapnia

Pathophysiologyofacutehypoxemicrespiratoryfailure

Disadvantages System

Slowercorrectionofgasexchangeabnormalities Increasedinitialtimecommitment Gastricdistension(occursin

Levelsofevidence

A MultipleRCTs Recommended

B Atleast oneRCT Weakerevidence

C Caseseries/reports Canbetriedbutwithclosemonitoring

Indications

Airwayobstruction COPD(EvidenceA) FacilitationofweaninginCOPD(EvidenceA) Asthma(B) Extubation failureinCOPD(B) CysticFibrosis(C) OSA/obesityhypoventilation(C) Upperairwayobstruction(C)

NIV&stableCOPD

NIVincreasinglyusedinstableverysevereCOPD

NIV+O2 therapy inselectedpatientswithpronounceddaytimehypercapnia

Clearbenefitsinbothsurvival&riskofhospitaladmissioninpatientswithbothCOPD&OSA

GlobalinitiativeforChronicObstructiveLungDisease(GOLD)update2013

CochraneDatabaseSyst Rev.2004;(3):CD004104.

Concludes

DatafromgoodqualityRCTsshowbenefitofNIVas1st lineinterventioninadditiontousualmedicalcaretoARF2 toanacuteexacerbationofCOPDinallsuitablepatients

Useearly inthecourseofrespiratoryfailureandbeforesevereensues,asameansofreducing thelikelihoodofendotrachealintubation,treatmentfailureandmortality

NIVinCOPDexacerbation

MultipleRCTssupportasuccessrateof8085%

Hasbeenshowntoimproverespiratoryacidosis (pH&pCO2 )

Respiratoryrate,WOB,severityofbreathlessness,complicationslikeVAP, lengthofhospitalstay(EvidenceA)

Mortality&intubationratesarereduced(Evidence A)

GOLDupdate2013

NIVinCOPDexacerbation

Indications for NIV atleast one of the following Respiratory acidosis (pH

12trialsofmoderatetogoodquality ComparedtotheIPPVstrategy,NPPVsignificantlydecreased Mortality(RR0.55) VAP(RR0.29) LengthofstayinanICU(WMD*6.27)&hospital(WMD7.19day)

Totaldurationofventilation(WMD5.64day) Durationofendotrachealmechanicalventilation(WMD 7.81days)

CochraneDatabaseSyst Rev.2010;(8):CD004127.*Weightedmeandifference

ComparedtoIPPVNoninvasive weaninghadnoeffectonweaningfailuresorthedurationofventilationrelatedtoweaning

Concluded aconsistent,positiveeffectonmortalityandventilatorassociatedpneumonia

Respir Care.2012Oct;57(10):161925.

Indications

Hypoxemicrespiratoryfailure Acutepulmonaryedema CPAP(EvidenceA) Immunocompromised patients(EvidenceA) Postoperativepatients(B) ARDS(C) Pneumonia(C) Traumaorburns(C) Restrictivethoracicdisorders(C) Donotintubatepatients(C) Duringbronchoscopy(C)

CochraneDatabaseSyst Rev.2013;5:CD005351.

Concludes

Included32studies NIVisaneffectiveandsafeinterventionforthetreatmentofadultpatientswithacutecardiogenicpulmonaryoedema

EvidencetodateonthepotentialbenefitofNIVinreducingmortalityisentirelyderivedfromsmalltrialsandfurtherlargescaletrialsareneeded

Indications

Immunocompromised patients Particularlyexposedtoinfectiousriskrelatedtoinvasiveventilation

MultipleRCTssupportwheneverpossible,NIVshouldbetriedfirstinimmunocompromisedpatientswithhypoxemicRF

Respir Care.2011Oct1;56(10):15838.

Indications

Postsurgicalperiod Shownbenefitsafterlungresectional surgery,CABG,gastroplasty,highriskprocedureslikethoracoabdominal aorticprocedures

ShouldbeconsideredinselectedpostoperativepatientsathighriskofpulmonarycomplicationsorwithfrankrespiratoryfailureespeciallyinthesettingofunderlyingCOPDorpulmonaryedema

Indications

RestrictiveLungDisease Patientswithrestrictionrelatedtoanunderlyingneuromusculardisease andsuperimposedARFmaybenefitfromatrialofNIV

SmallcaseserieshavereportedthatusingNIPPVinpatientswithmyasthenic crisesmayavoidintubation

PATIENTSELECTION Step1

Anetiology ofrespiratoryfailurelikelytorespondfavourablytoNIV

Step2 Identifypatientsinneedofventilatory assistancebyusingclinicalandbloodgascriteria

Moderatetoseveredyspnea,tachypnea,andimpendingrespiratorymusclefatigue

COPDwithRR>24bpm HypoxemicrespiratoryfailurewithRR>3035bpm

Step3 ExcludepatientsforwhomNIVwouldbeunsafe

PREDICTORSOFNIVSUCCESSINACUTE

RESPIRATORYFAILURE Loweracuityofillness(APACHEscore) Abilitytocooperate;betterneurologicscore Abilitytocoordinatebreathingwithventilator Lessairleakage;intactdentition Hypercarbia,butnottoosevere(PaCO2 between45and 92mmHg)

Acidemia,butnottoosevere(pHbetween7.1and7.35)

Improvementsingasexchangeandheartandrespiratoryrateswithinfirst2hours

ExclusionCriteriaforNIV

Respiratoryarrestorneedforimmediateintubation Hemodynamicinstability Inabilitytoprotecttheairway(impairedcoughorswallowing)

Excessivesecretions Agitatedandconfusedpatient Facialdeformitiesorconditionsthatpreventmaskfromfitting

Uncooperativeorunmotivatedpatient Braininjurywithunstablerespiratorydrive Untreatedpneumothorax

ContraindicationstoNIV

Cardiacorrespiratoryarrest Nonrespiratoryorganfailure Severeencephalopathy(eg,GCS

EquipmentforNIV Ventilators

PortableNIVmachines Advantages

Portability Easeofuse Bettercompensationforleaks Betterexhalation

Disadvantages Cannotdeveloppressures>30cmH2O LackO2 blenders Lackofsophisticatedalarmsystems,batterybackup

Criticalcareventilators

VentilatorsforNIV

Volumecontrolledhomeventilators Firstmachinestobeused Limitedabilitytocompensateforleaks

Bilevel ventilators Mostcommonlyused EPAP&IPAP Singlelimbcircuit Goodefficiency&leakcompensation

ICUventilators Limitedleakcompensation

PortableBiPAP machines

RESMED RESPIRONICSphilips

ModesofNIV

Pressuremodes Bettertoleratedthanvolumecycledvents

Constantpositiveairwaypressure(CPAP)

Bilevel orbiphasicpositiveairwaypressure(BiPAP)

Pressuresupportventilation(PSV)

Volumemodes Initialtidalvolumesrangefrom10to15mL/kg

Control Assistcontrol Proportionalassistcontrol

CPAP

Amodeforinvasiveandnoninvasivemechanicalventilation

Providesstaticpositiveairwaypressurethroughouttherespiratorycycle bothinspiration&expiration

Facilitatesinhalationbyreducingpressurethresholdstoinitiateairflow

CPAP

Creats a"pneumaticsplint"fortheupperairway,preventingthesofttissuesoftheupperairwayfromnarrowingandcollapsing.

Increasefunctionalresidualcapacity Improvelungcompliance Opencollapsedalveoli Improveoxygenation Decreaseworkofbreathing

Decreaseleftventriculartransmural pressure,a erloadandCO

CPAPASB

Adaptiveservoventilation

Specificallytotreatcentralsleepapnea (CSA) Designedtovarysupportaccordingtoapatientsindividualbreathingrate

Automaticallycalculatesatargetventilation(90%ofthepatient'srecentaverageventilation)

Adjuststhepressuresupporttoachieveit

BiPAP Spontaneous

Airwaypressurecyclesbetweenaninspiratorypositiveairwaypressure(IPAP)andanexpiratorypositiveairwaypressure(EPAP)

Patient'sinspiratoryeffort triggerstheswitchfromEPAPtoIPAP

ThelimitduringinspirationisthesetlevelofIPAP Theinspiratoryphasecyclesoff,andthemachineswitchesbacktoEPAPwhenitdetectsacessationofpatienteffort(decreaseininspiratoryflowrate,oramaximuminspiratorytimereached typically23seconds)

BiPAP Spontaneous Vt variesbreathtobreathandisdeterminedbydegreeofIPAP,patienteffort,andlungcompliance

IPAPisnecessarilysethigherthanEPAPbyaminimumof5cmH2O

DifferencebetweenthetwosettingsisequivalenttotheamountofPSprovided

Spontaneousmodedependsonpatientefforttotriggerinhalation.Apatientbreathingatalowratecandeveloparespiratoryacidosis.

BiPAP canbedescribedasacontinuouspositiveairwaypressuresystemwithatimecycledorflowcycledchangeoftheappliedCPAPlevel

BiPAPS

BiPAP

Spontaneous/timed(ST)mode ThetriggerintheSTmodecanbethepatient'seffortoranelapsedtimeinterval,predeterminedbyasetrespiratorybackuprate.

Ifthepatientdoesnotinitiateabreathintheprescribedinterval,thenIPAPistriggered.Formachinegeneratedbreaths,theventilatorcyclesbacktoEPAPbasedonasetinspiratorytime.

Forpatientinitiatedbreaths,theventilatorcyclesasitwouldinthespontaneousmode.

BiPAP

Increasesininspiratorypressurearehelpfultoalleviatedyspnea

Increasesinexpiratorypressurearebettertoimproveoxygenation

Interface

Thedevicethatmakesphysicalcontactbetweenthepatientandtheventilatoristermedtheinterface

Types Nasalmask Nasalpillow Oronasal mask Fullfacemask Helmet

Interfacesshouldbecomfortable,offeragoodseal,minimizeleak,andlimitdeadspace

Interface

SelectionofacomfortablemaskthatfitsproperlyiskeytothesuccessofNIV

Fullfacemaskshouldbetriedfirstintheacutesetting

Patientshouldbeallowedtoholdthemaskinplaceinitially

Maskstrapsarethentightenedwiththeleasttensionnecessarytoavoidexcessiveairleakage

InterfacesfordeliveryofNIV

Oronasal maskinterface

Oronasal maskinterface

1st lineforacutecaresetting

COPD mouthbreathing

Nasalmasks

Bettertoleratedthanfullfacemasksforlongterm&chronicapplications

Lessclaustrophobiaanddiscomfortandalloweating,conversation,andexpectoration

Nasalmasks

Pressureovernasalbridge foreheadspacers ultrathinsiliconsealsorheatsensitivegelsthatminimizeskintrauma

Problem Airleakagethroughmouth

Nasalpillows

Nasalvs Oronasal mask

Variables Nasal Oronasal

Comfort +++ ++

Claustrophobia + ++

Rebreathing + ++

LowersCO2 + ++

Permitsexpectoration ++ +

Permitsspeech ++ +

Permitseating +

Functionifnoseobstructed +

Totalfacemask

Equallycomfortable Similar

Applicationtimes EarlyNIVdiscontinuationrates

Improvementsinvitalsignsandgasexchange

Intubationandmortalityrates

CHEST2011;139(5):10341041

Helmetvs Facemask

Helmet equallytolerated effectiveinamelioratinggasexchange

decreasinginspiratoryeffort

Butlessefficientindecreasinginspiratoryeffort

worsenedthepatientventilatorinteraction

IntensiveCareMed.2007Jan;33(1):7481

ProtocolforinitiationofNIV

Appropriatelymonitoredlocation Patientinbedorchairsittingat>30degreeangle Afullfacemaskshouldbeusedforthefirst24hours,followedbyswitchingtoanasalmaskifpreferredbythepatient(EvidenceC)

Encouragepatienttoholdmask Applyharness;avoidexcessivestraptension Connectinterfacetoventilatortubingandturnonventilator

Checkforairleaks,readjuststrapsasneeded

ProtocolforinitiationofNIV

Checkforairleaks,readjuststrapsasneeded Considermildsedation(lorazepam 0.5mgiv)inagitatedpatients

Encouragement,reassurance,andfrequentchecksandadjustmentsasneeded

Monitoroccasionalbloodgases(within1to2handthenasneeded)

GuidelinesforprovidingNIV

AninitialIPAPof10cmH2O&EPAPof45cmH2O shouldbeused(EvidenceA)

IPAPshouldbeincreasedby25cmincrementsatarateofapproximately5cmH2Oevery10mins,withausualIPAPtargetof20cmH2Ooruntilatherapeuticresponseisachievedorpatienttolerabilityhasbeenreached(EvidenceA)

O2 shouldbeentrainedintothecircuitandtheflowadjustedtoSpO2 >8892%(EvidenceB)

BTS:NIVinCOPD:managementofacutetype2respiratoryfailure

GuidelinesforprovidingNIV

Bronchodilators preferablyadministeredoffNIV ifnecessarybeentrainedbetweentheexpirationportandfacemask

DeliveryofbothoxygenandnebulisedsolutionsisaffectedbyNIVpressuresettings(EvidenceA)

Ifanasogastrictubeisinplace,afineboretubeispreferredtominimisemaskleakage(EvidenceC)

BTS:NIVinCOPD:managementofacutetype2respiratoryfailure

GuidelinesforprovidingNIV

Patientcomfortandenhancedcompliancearekeyfactorsindeterminingoutcome(EvidenceA) Synchronyofventilationshouldbecheckedfrequently.

Aclinicalassessmentofmaskfittoincludeskinconditionanddegreeofleak(particularlyontothecorneas)shouldbeperformedatthesametime

BTS:NIVinCOPD:managementofacutetype2respiratoryfailure

OXYGENATIONANDHUMIDIFICATION

Oxygenistitratedtoachieveadesiredoxygensaturation>90%to92% Useofoxygenblenders adjustinglitreflowdeliveredviaoxygentubingconnecteddirectlytothemaskorventilatorcircuit

Heatedblowovervaporisershouldbeusediflongerapplicationintended

Monitoring

Subjectiveresponses Bedsideobservation Askaboutdiscomfortrelatedtothemaskorairflow

Physiologicresponse RR,HR,BP,continuousEKG Patientbreathinsynchronywiththeventilator accessorymuscleactivityandabdominalparadox MonitorairleaksandVt

Monitoring

Gasexchange(EvidenceC) ContinuousSpO2andECGduringthefirst12hours ABG

After1hourofNIVtherapyand1houraftereverysubsequentchangeinsettings

After4hours,orearlierinpatientswhoarenotimprovingclinically

BTS:NIVinCOPD:managementofacutetype2respiratoryfailure

GuidelinesforprovidingNIV

Durationoftreatment PatientswhobenefitfromNIVduringthefirst4hoursoftreatmentshouldreceiveNIVforaslongaspossible(aminimumof6hours)duringthefirst24hours (EvidenceA)

Treatmentshouldlastuntiltheacutecausehasresolved,commonlyafterabout3days

WhenNIVissuccessful(pH>7.35,resolutionofcause,normalisation ofRR)after24hrs/moreplanweaning

BTS:NIVinCOPD:managementofacutetype2respiratoryfailure

AssessmentofNIV

Weaningstrategy(A)

ContinueNIVfor16hoursonday2 ContinueNIVfor12hoursonday3including68hoursovernightuse

DiscontinueNIVonday4,unlesscontinuationisclinicallyindicate

BTS:NIVinCOPD:managementofacutetype2respiratoryfailure

CriteriaforTerminatingNIVandSwitchingtoInvasiveMechanicalVentilation

WorseningpHandPaCO2 Tachypnea (over30bpm) Hemodynamicinstability SpO2

Complications

Interfacerelated Airpressure/flowrelated

Patientrelated

Conclusion

NIVisanimportanttooltotideoveranacuteinsultinthehandsofaexperiencedoperator

Keyfactorsinsuccess Evidencebasedapplicationforselectedetiologies Carefulpatientselection/rejection Skilledinitiation&application Algorithmicapproachininitiation,use,discontinuation

Patientcomfort&avoidingdyssynchrony Avoidingcomplications

Conclusion

Mostimportantly Decisionmakingonwhen toswitchtoinvasivemechanicalventilationinasettingoffailureofNIV

THANKS