Andersons pediatric cardiology 2093

Developmentofstandardizedacutekidneyinjury(AKI)definitionsandstaging
criteriahaveledtoanappreciationoftheassociationbetweenAKIandpoor
outcomesinchildrenwithheartdisease.2–5Theevolutionofthesedefinitions
andcriteriahaveculminatedinaharmonizedconstructfromtheKidneyDisease
ImprovingGlobalOutcomes(KDIGO)AKIWorkGroup(Table78.2).Asnoted
above,thecriticalclinicalandepidemiologicadvancefromastandardizedAKI
definitionandstagingcriteriahasbeentherealizationthateventhedoublingof
serumcreatinineor12hoursofoliguriaareassociatedwithmorbidityand
mortalityinchildren.6
Table78.2
KidneyDiseaseImprovingGlobalOutcomesAcuteKidneyInjuryWorkGroupCriteria
SerumCreatinineCriteria
Increaseby≥0.3mg/dLwithin48h
or
Increaseto1.5timesbaseline,whichisknownorpresumedtohave
occurredwithintheprior7days
Stage
1.5–1.9timesbaseline
1
or
Stage
≥0.3mg/dLincrease
2
2.0–2.9timesbaseline
Stage
3.0timesbaseline
3
or
Increaseinplasmacreatinineto≥4.0mg/dL
or
Initiationofrenalreplacementtherapya

or
Inpatientsage<18y,adecreaseineGFRbto<35mL/min/1.73m2

Definition

UrineOutputCriteria
Urinevolume<0.5
mL/kg/hfor6h

<0.5mL/kg/hfor6–
12h
<0.5mL/kg/hfor
≥12h
<0.3mL/kg/hfor
≥24h
or
Anuriafor≥12h

aRenalreplacementtherapyutilizationwasassessedasanoutcomeforthecurrentstudyandis

omittedfromstage3.
beGFRwascalculatedfromtheoriginalSchwartzformula,whereeGFR=k×patientheight

(cm)/plasmacreatinine(mg/dL)andkisaconstantdefinedas0.45(infant<1year),0.55(childor
adolescentfemale)or0.70(adolescentmale).70
eGFR,Estimatedglomerularfiltrationrate.
FromKidneyDisease:ImprovingGlobalOutcomes(KDIGO)AcuteKidneyInjuryWorkGroup.
KDIGOClinicalPracticeGuidelineforAcuteKidneyInjury.KidneyIntSuppl.2012;2:1–138.

PostCardiacSurgery

Themostcommonandmoststudiedacutecardiorenalsyndromeseeninthe
pediatricsettingoccursaftercardiacsurgeryinvolvingcardiopulmonarybypass


(CPB).Thefocusonthispopulationresultsfromtheclinicalscenarioproviding
avirtuallyuniquesituationinwhichtostudyAKIcomparedtootherhospitalacquiredconditionsleadingto,orassociatedwith,AKI,whichhavebeenthe
subjectofclinicalandtranslationalresearch(Table78.3).Thefactthat(1)the
timingofrenalinsult,ischemicinjuryassociatedwiththeCPBprocedure,is
known;(2)KDIGO(orequivalent)AKIratesarehigh(30%to60%)andmore
severeKDIGOStage2or3ratesarealsohigh(10%to20%)7–13;and(3)this
populationhasfewothercomorbiditiesprovidesanidealclinicalenvironment
forepidemiologicandclinical/translationresearch.
Table78.3
ClinicalSettingCharacteristicsforPediatricHospital-Acquired
AcuteKidneyInjuryandImpactonClinicalandTranslational
Research
Setting
Postcardiac
surgery
GeneralICU
Nephrotoxic
exposure
Emergency
center

Timingof
AKIRates
Insult
Known
Known

(30%–40%)
Unknown Known
(20%–30%)
Known
10%–20%

FrequencyofLab
Monitoring
Atleastdaily

Unknown

Singletimepoint

Unknown

Atleastdaily
Variable

UrineAssessments
Availablevia
indwellingcatheter
Availablevia
indwellingcatheter
Notroutinely
available
Singletimepoint

Translational
Assessments

Multiplebiomarker
studies
Multiplebiomarker
studies
Fewsingleagent
biomarkerstudies
Fewsingletimepoint
studies

AKI,Acutekidneyinjury;ICU,intensivecareunit.

CPBinducesAKIbymechanismsthataremultifactorialandcomplex,but
includesischemicinsultfollowedbyareperfusioninsult,lossofpulsatilerenal
bloodflow,renalvasoconstriction,andmicroemboli.Thecellularbiochemistry
ofCPB-inducedAKIisalsoquitecomplexandisdepictedinFig.78.1.14Given
thehighincidenceofpost-CPBAKI,numerouspre-andintraoperativerisk
factorshavebeenidentifiedtoassistinAKIprediction(Table78.4).15Of
particularnote,ageyoungerthan2years,CPBdurationofgreaterthan90
minutes,16andsingleventricularphysiologyappeartohavestrongassociations
withthedevelopmentofpostoperativeAKI.


FIG.78.1 Renaltubularcellalterationsafterischemicacutekidneyinjury.
ATP,Adenosinetriphosphate;Ca,calcium;Fe,iron;iNOS,induciblenitric
oxidesynthase.(FromDevarajanP.Updateonmechanismsofischemic
acutekidneyinjury.JAmSocNephrol.2006;17[6]:1503–1520.)

Table78.4
RiskFactorsforAcuteKidneyInjuryDevelopmentAfterCardiopulmonaryBypass
Durationofcardiopulmonarybypass

Youngage
Younggestationalage
HigherRACHS-1category
Higherpreoperativeserumcreatinine
Lowerpreoperativeserumcreatinine
Longerintraoperativetime
Multiplecrossclamps
Functionalsingleventricle
Preoperativeinotropicsupport
PreoperativeAKI
Preoperativemechanicalventilation
Preoperativeperitonealdialysis