Rev. Bras. Anestesiol. vol.66 número6

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REVISTA

BRASILEIRA

DE

ANESTESIOLOGIA

PublicaçãoOficialdaSociedadeBrasileiradeAnestesiologia

www.sba.com.br

SCIENTIFIC

ARTICLE

Non-invasive

mechanical

ventilation

after

the

successful

weaning:

a

comparison

with

the

venturi

mask

Esra

Adıyeke,

Asu

Ozgultekin,

Guldem

Turan

∗

_,

_Altay

_Iskender,

_Gamze

_Canpolat,

Abdullah

Pektas

¸,

Osman

Ekinci

HaydarpasaNumuneTeachingandResearchHospital,DepartmentofICU,Istanbul,Turkey

Received6April2014;accepted11November2014 Availableonline20October2015

KEYWORDS

Artificialrespiration;

Weaning;

Criticalcare

Abstract

Backgroundandobjectives: Thisstudycomparedtheratesofacuterespiratoryfailure, rein-tubation,length ofintensive care stay andmortality inpatients inwhom thenon-invasive mechanicalventilation(NIMV)wasappliedinsteadoftheroutineventurifacemask(VM) appli-cationafterasuccessfulweaning.

Methods:Followingtheapprovalofthehospitalethicscommittee,62patientswhowereunder mechanicalventilationfor atleast48hourswere scheduledforthisstudy.12patients were excludedbecauseoftheweaningfailureduringT-tubetrial.Thepatientswhohadoptimum weaningcriteriaaftertheT-tubetrialof30minuteswereextubated.Thepatientswerekepton VMfor1hourtoobservethehemodynamicandrespiratorystability.Thegroupof50patients whowere successfultoweanrandomlyallocatedtohaveeitherVM (n=25),orNIV(n=25). Systolicarterialpressure (SAP),heart rate(HR),respiratory rate(RR), PaO2,PCO2, andpH

valueswererecorded.

Results:ThenumberofpatientswhodevelopedrespiratoryfailureintheNIVgroupwas sig-nificantlylessthanVMgroupofpatients(3reintubationvs.14NIV+5reintubationintheVM group).ThelengthofstayintheICUwasalsosignificantlyshorterinNIVgroup(5.2±4.9vs. 16.7±7.7days).

Conclusions:TheratiooftherespiratoryfailureandthelengthofstayintheICUwerelower when non-invasive mechanicalventilationwas used after extubation evenif the patient is regardedas‘successfullyweaned’.WerecommendtheuseofNIMVinsuchpatientstoavoid unexpectedventilatorfailure.

∗_{Corresponding}_author.

E-mail:gturanmd@yahoo.com(G.Turan). http://dx.doi.org/10.1016/j.bjane.2014.11.008

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PALAVRAS-CHAVE

Respirac¸ãoartificial;

Desmame;

Cuidadosintensivos

Ventilac¸ãomecânicanãoinvasivaapósdesmamebem-sucedido:umacomparac¸ão comamáscaradeVenturi

Resumo

Justificativaeobjetivos: Esteestudocomparouastaxas deinsuficiênciarespiratória aguda, reintubação,tempodeinternaçãoemUTIemortalidadeempacientessobventilaçãomecânica não invasiva(VMNI)em vezdahabitualmáscarafacialdeVenturi(MV)apósdesmame bem-sucedido.

Métodos: Apósa aprovaçãodo Comitêde Ética dohospital, 62 pacientesqueestavam sob ventilação mecânica porno mínimo 48 horasforam inscritosneste estudo.Doze pacientes foramexcluídosdevidoàfalhadedesmameduranteotestedetubo-T.Ospacientesque apre-sentaramcritériosdedesmameótimosapósotestedetubo-Tde30minutosforamextubados. OspacientesforammantidosemMVpor1horaparaobservaçãodaestabilidadehemodinâmica erespiratória.Ogrupode50pacientesqueobtiveramsucessonodesmameventilatórioforam alocadosaleatoriamenteparaMV(n=25)ouVNI(n=25).Osvaloresdepressãoarterialsistólica (PAS),frequênciacardíaca(FC),frequênciarespiratória(FR),PaO2,PCO2epHforam

registra-dos.

Resultados: OnúmerodepacientesquedesenvolveuinsuficiênciarespiratórianogrupoVNIfoi significativamente menorqueodo grupoMV (3reintubac¸ões vs.14 VNI+5reintubac¸ões no grupoMV).OtempodepermanênciaemUTItambémfoisignificativamentemenornogrupoNIV (5,2±4,9vs.16,7±7,7dias).

Conclusões: AstaxasdeinsuficiênciarespiratóriaedotempodepermanênciaemUTIforam menoresquandoaventilac¸ãomecânicanãoinvasivafoiusadaapósaextubac¸ão,mesmoseo pacienteforconsideradocomo‘‘desmamebem-sucedido’’.RecomendamosousodeVMNIem taispacientesparaevitarafalhainesperadadoventilador.

Introduction

Non-invasiveventilationtakesaroleindifferentstagesof treatmentinintensivecareunits.Thismethodiscommonly usedasanalternativetoinvasiveventilationinpatientswho areclinicallystablebutsufferfromacutehypercapnic respi-ratory failure.1---3 _NIV _is _also _used_for _premature _weaning andpostextubationrespiratoryfailureandpositiveresults onreintubationand durationof intensivecare unitstayis reported.4

Inthisstudy,weaimedtodetermineifprophylacticNIV appliedto thepatients whowere extubated according to thestandardizedweaningcriteriaandwhowere appropri-ateforfollowingwithventurefacemask(VM)wouldmake anydifferenceintermsofrespiratoryfailureafter extuba-tion,reintubation,durationofintensivecareunitstayand mortality.

Materials

and

methods

Sixty-two patients above18-yearsoldwhowere admitted to intensive care unit with acute respiratory failure and treated with invasive mechanical ventilatory support for morethan48hwereincludedinthestudy.Patientswhose APACHEII(AcutePhysiologyandChronicHealthEvaluation II) score above 25, GCS (Glasgow Coma Scale) below 13 andwhohavecontraindicationsforNIV(patientswith max-illofacial trauma, gastrointestinal obstruction and severe

secretion),severeirreversibleorganfailureandpregnancy were excluded from the study. Demographic data, diag-nosis,comorbidities, andAPACHEII scores of thepatients wererecorded.Weaningwasplannedforthepatientswho haveoptimalconditions:CPAPmodewithinvasivemechanic ventilationsupportwhohaveFiO≤40,PaO2≥60,PEEP≤5, SO2≥90 and not having inotrope support; systolic arte-rial pressurebetween 70 and 180mmHg,peak heart rate between50and140min,respiratoryrate<25min,GCS≥13. Patientswhofulfilledthesecriteriaweretakenunder spon-taneous respiratory trial with T-part for 30min. Arterial bloodgaswasevaluatedafter30minspontaneous respira-torytrial.Ifhemodynamicandrespiratoryparameterswere stable,patientswereextubatedandsupportedwithO2by VM.Patientswerefollowedupforanhourtoobserve suffi-ciencyintermsofweaningandtheoneswhohadSO2≥90, systolicarterialpressurebetween70and180mmHg,peak heartratebetween50and140min,respiratoryrate<25min wereincluded inthestudy.Thepatientswerechoseninto thegroupsaccordingtotheadmissionnumberashavingodd orevennumber.

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group. Mechanical ventilation parameters of the patients supportedbyNIVweresetasIPAP:13---15cmH2Ovs.EPAP: 3---5cmH2Oaccordingtopatientcompliance.Differenttypes ofNIVmasks(full-faceandoronasal-foreheador chin sup-ported) were chosen for application in order to provide patientcomfortandcompliance.Duringthefollow-up,low dosedexmedetomidinesedation(0.2---0.5mg/kg/hinfusion) wasplannedtobeinitiatedifthepatient’sincompliancewas preventingNIVtobeeffective.

Arterial pressure, pulse, respiratory rate and arterial blood gas parameters were recorded before extubation, underIMVinCPAPmode;inthe30thminuteofT-piecetrial; andafterextubationin1st,2nd,3rd,4th,5th,6th,12th, 24th,48th hoursin all patients. Complications(vomiting, airwayobstruction,regurgitation,etc.)wererecorded.

InGroupVM,patientswhodidnothaverespiratoryfailure andintubationindicationbutdevelopedrespiratory deterio-rationandslighthypoxia(respiratoryrate>25min,SO2≤95, PaO2≤70mmHg)weresupportedwithNIV;whilepatientsin bothgroupswhohadrespiratoryfailureandintubation indi-cation (respiratory rate>35min, SO2<90, PaO2<60mmHg andhemodynamicfailure)werereintubated.

Continuityof weaningsuccess,respiratoryfailureafter extubation, reintubation, duration of intensive care unit stay and mortality rates are compared between two groups.

During the evaluation of the data obtained from the study,SPSS(StatisticalPackageforSocialSciences)for Win-dows 20.0 program was used for the statistical analysis. DistributionofvariableswascontrolledbyusingKolmogorov Smirnov Test. During the evaluation of the study data, regardingthe comparisonsof descriptivestatistical meth-ods(frequency,rate,mean,andstandarddeviation)aswell asquantitative data, Studentt test and Mann Whitney U

tests were used. Chi-square test was used regarding the comparisonofthequalitativedata.Pairedsamplettestand Wilcoxontestswereusedforrepetitivemeasurements.The resultsobtainedfromthestudywereevaluatedwithin95% confidenceintervals andat asignificance level ofp<0.05 level.

Results

Thestudywasconductedon62patientswithacute respira-toryfailurewhowerehospitalizedintheintensivecareunit ofourclinic andhad invasivemechanical ventilatory sup-portfor morethan48h.Elevenof thesecasesdeveloping respiratoryfailureinthe1sthourofextubationand1case operatedforacuteabdomenonthe12thhourofthestudy wereexcluded fromthe study.The remaining50 patients inbothgroupswhowerefollowed-upwithVMaftera suc-cessfulweaning for 1h were included inthe study.There wasnosignificantdifferencebetweentwogroupsregarding age, gender distribution and APACHE II scores (p>0.05) (Table1).

Thestudyperiodwas48hafterextubation.Systolicblood pressure,peakheartrate,respiratoryrate,PaO2andPaCO2 andpHvalueswererecordedandcomparedatcertaintime intervals.

WhenT-circuitwasatthe30thminuteinGroupVMand Group NIV, there was no significant difference (p>0.05)

Table1 Baselinecharacteristicsofthepatients.

GroupVM GroupNIV p-value

Age 67.84±17.31 71.88±11.00 0.330

Sex

F 15(60%) 12(48%) 0.395 M 10(40%) 13(52%)

APACHEII 20.76±7.03 19.54±4.46 0.474

betweensystolicbloodpressurevaluesinthe1st,2nd,3rd,

4th,5th,6th,12th,24th,48thhours.

WhenT-circuitwasatthe30thminuteinGroupVMand

Group NIV, there was no significant difference (p>0.05)

between peakheartratevaluesin the1st,2nd,3rd,4th,

5th,6th,12th,24th,48thhours.GroupVMhadsignificantly

higherpulserates(p<0.05)thanGroupNIVinthe2ndhour

(98.7±15.1;90.3±13.6;p=0.045).

between respiratoryrate(RR)valuesinthe1st,2nd,3rd,

4th,5th,6th,12th,24th,48thhours.

betweenPCO2valuesinthe1st,6th,12th,24th,48thhours.

betweenPO2valuesinthe1st,12th,24th,48thhours.Group

VMhadsignificantlylowerPO2values(p<0.05)thanGroup

NIVinthe6thhour(90.2±25.6;112±29.2;p=0.015).

Respiratory failure developed in 19 of the 25 patients

(76%) in Group VM, whereas it developed only in 3 (12%)

ofthe25 patientsinGroupNIV afterextubation.Ingroup

VM,14ofthe19patients(73%)NIVsupportwasinitiated,5

patients(26%)weredirectlyreintubated.Four(80%)ofthe

5 patientswho weredirectly reintubated weredied after

the 48h study period, during their stay in ICU with

pro-gressiverespiratoryfailureduetoCOPD+Pnemoniainone

and with acutecerebral bleeding, malignancy, abdominal

sepsisdevelopedaftercolonperforationintheotherthree

patients.

Respiratoryfailuredevelopedafterextubationinonly3

(12%) of 25 patients of groupfollowed with NIV andthey

werereintubated.Two (66%)oftheseweredied afterthe

study periodbefore weaning. The causes of deaths were

again relatedto theextrapulmonary reasons (acute

cere-brovascularocclusionandacutecoronarysyndrome).

NIVwasprovidedin14patients(56%)inGroupVM

devel-opingrespiratoryfailureduringfollow-upwithventurimask

andtheycouldbedischargedfromthehospitalwithoutany

needofreintubation.IngroupVMpatientswhoneededNIV

support,asignificantdecreasewasobservedinPO2valueat

the6th---12thhoursandasignificantincreaseVM.

TheuseofNIVsupportdecreasedrespiratoryfailureratio

afterextubationby64%,andreintubationandmortalityrate

by 8%. Comparing the twogroups in terms of respiratory

failure after extubation a significant difference wasseen

(p<0.05).Nosignificantdifferencewasdetectedregarding

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Table2 Nosignificantdifferencewasdetectedregarding reintubationandmortalityratios.

GroupVM GroupNIV p-value

Respiratoryfailure afterextubation

19(76%) 3(12%) 0.000

Reintubation 5(20%) 3(12%) 0.702 Durationofintensive

careunitstay

16.7±7.7 5.2±4.9 0.000

Outcome

Exit 4(16%) 2(8%) 0.304 Alive 21(84%) 23(92%)

Discussion

Currentroutineclinicalpracticeof theweaningprocessis

toextubate thepatients eligiblefor weaning criteriaand

follow-upthegroupwhoseemtobestabilizedintermsof

respirationwithVM.

While this process is well tolerated by some patients

andweaningprocesscan easilybecompleted,during

pro-longed VM period, some patients may need respiratory

supportdue to insufficiency of ventilation capacity, rapid

superficialbreathing,inabilitytoprotectairway,secretion

collectionandatelectasisformationintheadvancinghours

eventhoughtheyseemtobestabileinthefirsthoursofthe

process.4---7_To_be_insistent_on_VM_follow-up_for_these_groups

ofpatientsmaycausethepatienttolosetheopportunityfor NIVleadingtothereintubationprocesswithaccompanying risks.

Weperformedourstudyonthepatientswhofulfilledthe weaning criteria, kept respiratory and hemodynamic sta-bility after 30min T-piece trial and then extubated. We aimed to observe the effects of NIV support on respira-toryfailuredevelopment,durationofstay intheintensive care unit and mortality rates in this patient group who were allowable for follow-up with venturi mask, namely thepatientsforwhomrespiratoryfailurewerenotforeseen undernormalconditions.Wepreferredtouse NIVsupport continuouslyfor48hinourpatients.However,wealso car-riedout a protocol basedoncare, feeding andshortrest intervals considering patient comfort. When the patients withoronasalmaskwereobservedtohavenasalpressure, full-facemaskalternativewasusedtopreventnasalinjury. None of the patients sufferedfrom complications suchas gastricdistension,regurgitationandvomitingandtherewas noneedforsedationinanygroup.

Nava et al. investigated NIV use in patients fulfilling weaning criteria but at risk for respiratory failure after extubationalsousedasimilarmethod(successiveNIV appli-cations in the first 48h). In this study, 97 patients were dividedintotwogroupsasstandardmedicaltreatment(VM) or NIVuse. While12 of49 patientsin controlgroup were reintubated,4of48patientsinNIVgroupwerereintubated (p=0.027). Hence, the use of NIV decreased reintubation by16%andtheriskofintensivecareunitmortalityby10% (p<0.01).Besides these,need for reintubationwasfound tobe associatedwitha 60% increasein the risk of inten-sive careunitmortality (p<0.01).When durations ofstay intheintensivecareunitofthepatientswithreintubation

needwerecomparedwiththeother patients, itwasseen thatitwasstatisticallysignificantlylonger(28.3±29.5vs. 8.6±5.1).Theseresearchersconcludedthattheinhibitory use of NIV decreased the requirement of reintubation in patientsubgroupspassing spontaneousbreathingtrialsbut havingrespiratoryfailureriskafterextubation.5

Similarresults were found in another study performed byFerrer etal.6 _In _this _study,_like _ours, _NIV _was_used _as anpreventivetreatmentmethodforthepatientswhowere successfullyweanedaftertheT-piecetrial,andcomparedto thecontrolgroupwhohadventurimaskinstead.Asaresult ofthestudyperformedon162patients,researchersfound thattheuseofNIVdecreased theincidenceofrespiratory failureafterextubationconsiderablyandintensivecareunit mortalityratealsodecreased.However,theycouldnotfind asignificantdifferencebetween90-daysurvivalratesofthe twogroups.

We chose our study group from the patients in whom respiratoryfailurewasnotforeseenafterextubation.Ifany deteriorationduring the follow-up periodoccurs; that is: respiratoryrateabove25breaths/min,SO2:90%andbelow; PO2:70mmHgandbelow;NIVappliedtothepatientunder VM.Iftherespiratoryrateabove35breaths/min,SO2:90% andbelow;PO2:60mmHgandbelowor thehemodynamic parameterswereimpaired,thepatientsinbothgroupswere directly intubated to have invasive mechanical ventilator support.NIVwasprovidedin14patients(56%)inGroupVM developingrespiratoryfailureduringfollow-upwithventuri maskandthesepatientscouldbedischargedfromhospital withoutanyneedofreintubation.

Intheirstudyperformedon158patients,Medurietal.7 showedthatNIVcouldbeaneffectivemethodtotreat respi-ratoryfailureafterextubationand65---70%ofthepatients whosereintubationwasunavoidablecouldbenefitfromNIV. Thirty-nineofthesepatientsweresupportedwithNIVdueto respiratoryfailureafterextubationandanimprovementwas observedinarterialbloodgasvaluesof88%ofthem. There-fore,the need for reintubation removed in 65% of these patients.

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NIV support could beused carefully in patients devel-opingrespiratoryfailureafterextubationbut itshouldbe takenintoconsiderationthatdangerousdelaysin reintuba-tionduringtreatmentofrespiratoryfailureafterextubation withNIV supportcouldresultinadverse outcomesforthe patients.Intheirmeta-analysisperformedbyreviewingthe studiesonthissubject,Agarwaletal.concludedthatitis suggestedthatprotocolsshouldbedevelopedforNIVusein thepatientsatriskfordevelopingrespiratoryfailureafter extubation.8

Inourstudy,weobservedthatprovisionofprophylactic NIV support for at least 48h after weaning under opti-malconditionsinthepatientswhohadinvasivemechanical ventilatorysupportfor morethan48hdue toacute respi-ratory failure and for whom respiratory failure were not foreseen after extubation decreased the duration of stay in the intensive care unit and risk for respiratory fail-ure that could develop. Although the use of NIV is not suggested except the patients at high risk for extuba-tion success; based onthe results we obtained from our study,weconsiderthattheprophylacticuseofNIVcanbe beneficial.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

References

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