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CardiovascularMain.209-218Q1A1-day-oldboyisadmittedtotheneonatalintensivecareunitwithcyanosis.Theinfantwasbornattermafteranuncomplicatedpregnancyandwasinitiallyroominginwithhisparents.Approximately2hoursago:hebegantodevelopcyanosis.Bloodpressureis30/40mmHgInall4extremities,heartrateis140/mintandrespirationsare55/min.Pulseoximetryshows30%anddoesnotimprovewith100%inspiredoxygendeliveredbyanoxyhood.Theinfantisbreathingcomfortablybutisdiffuselycyanotic,includinghisoralmucosa.Acontinuousmachine-likemurmurisheardonauscultation.Chestx-rayrevealsclearlungfields.WhichofthefollowingisthebestnextstepInmanagementofthispatient?A.FurosemideB.IndomethacinC.Intubationwith100%fractionofinspiredoxygenD.PropranololE.ProstaglandinE1F.RedbloodceiltransfusionA1Correctanswer:EThisinfanthascyanosisandhypoxiathatfailtoimprovewithatrialof100%oxygen(hyperoxiachallenge).Thesefindingsareconcerningforacongenitalheartdefect.Cyanoticcongenitalheartdiseasesarecausedbydeoxygenatedbloodfromtherightventriclebeingshuntedtothesystemiccirculation,inmanycases,thepulmonarybloodflowcomesnotfromtherightventricleitselfbutratherfromleftventricularoutputthroughthepatentductusarteriosus(PDA),AsthePDAbeginstoclose,thepulmonarybloodflowdecreasesandthecyanosisbecomesmoreapparent,asinthisinfant.Similarly,someconditions(eg,hypoplasticleftheartsyndromeorseverecoarctationoftheaorta)requirethePDAtoprovidesystemic(ratherthanpulmonary)bloodflow,andwillalsopresentastheductusclosesoverthefirstfewdaysoflife.Theexactnatureofthemalformationcanbeconfirmedbyechocardiogram,buttheimmediatefirststepistoadministerprostaglandintherapy.ProstaglandinE1isavasodilatorandcanpreventthePDAfromclosing,therebymaintainingpulmonarybloodflow.Promptprostaglandinadministrationcanbelife-savingandshouldnotbedelayed.(ChoiceA)Loopdiuretics,suchasfurosemide,areusedtotreatheartfailurecausedbyventricularoverload(eg,ventricularoratrialseptaldefects).Heartfailuredevelopsoverweekstomonths,andthispatienthasnosignsofvolumeoverload.(ChoiceB)indomethaciniscontraindicatedinthisinfantasitisapotentprostaglandininhibitorthatwouldrapidiyclosethePDA.(ChoiceC)Thisinfanthasnoevidenceoflungdiseaseeitheronexaminationorx-ray,andhasalreadyfailedatrialof100%oxygen,intubatingthischildtoprovideadditionalpressurewillnotimprovehishypoxiaandmayworsenthePDA-dependentpulmonarybloodflow.(ChoiceD)Betablockersareusedtotreatarrhythmiasandheartfailureassociatedwithcongenitalheartdisease.Thispatienthasnoevidenceofheartfailureorarrhythmia.(ChoiceF)Anemiadoesnotcausecyanosisoraffectpulseoximetry.Redbloodcel!transfusionsshouldnotbegiventoinfantswithoutlaboratoryevidenceofanemiaoraclinicalhistorythatisconsistentwithbloodloss.Educationalobjective:ProstaglandinE1infusionmaintainspatencyoftheductusarteriosusandispotentiallylife-savingininfantswithductal-dependentcongenitalheartdisease.Onceprostaglandinsareadministered,echocardiographycanidentifythespecificcardiaclesion.Q2Anewborngirlisevaluatedintheneonatalintensivecareunitforcyanosis.Shewasbomat36weeksgestationbycesareansectionforfetaldistress.Thegirlremainedhypoxicdespiteadministrationofsupplementaloxygen.Onexamination,sheiscyanoticandtremulous.Shehaslow-setears,micrognathia,andacleftpalate.Chestradiographshowsanabsentthymus.Echocardiographyconfirmstruncusarteriosus.Thispatientisatgreatestriskforwhichofthefollowing?A.DuodenalatresiaB.HypocalcemiaC.HypoglycemiaD.InfertilityE.MyelomeningoceleF.NeutropeniaG.ThrombocytopeniaA2Correctanswer:BDiGeorgesyndrome(DGS)isdisorderusuallycausedbythemicrodeletionofchromosome22q11，resultinginpoordevelopmentofthepharyngealpouchsystemandsubsequentabnormalitiesoftheface,neck,andmediastinum.Theclinicalpresentationtypicallyincludesthepentadofcongenitalheartdisease,facialdysmorphia,thymichypoplasia,cleftpalate,andhypocalcemia.OnceDGSissuspected,serumcalciumlevelsandechocardiographymustbeorderedimmediately.Hypocalcemiaresultsfromhypoplasiaoftheparathyroidglands.Neonatesareathighriskforlife-threateningtetany,seizures,andarrhythmiasthatcanfurtherexacerbateco-existingheartproblemsandmayrequireaggressivecalciumrepletion.EchocardiographyiscriticalasthecardiacanomaliesinDGSarevariableandplacethepatientatgreatriskforheartfailureandhypoperfusion.TruncusarteriosusisstronglyassociatedwithDGS，andothercommonconditionsincludetetralogyofFallot,interruptedaorticarch,andseptaldefects.Dependingonthedegreeofthymichypoplasia,patientscanhaveT-celllymphopeniaandincreasedriskofviralandfungalinfections.HumoralimmunodeficiencycanalsoresultfromdefectiveT-cellhelpinB-cellactivationforantibodyproduction,increasingsusceptibilitytobacterialinfectionsaswell.Therefore,allpatientswithDGSshouldreceiveroutinekilledorsubcomponentvaccines.However,thesafetyoflivevaccines(measles-mumps-rubeila.intranasalinfluenza,rotavirus,andoralpoliovirusvaccines)forthesepatientsdependsonthedegreeofimmunodeficiency.Decisionsregardingadministrationshouldbetailoredtothepatient'simmunestatus.(ChoiceA)Congenitalheartdiseaseandlow-setearsareseeninDownsyndrome.Thesepatientsareatincreasedriskofduodenalatresia.Howe