n zealand obstetric doppler uideline

NewZealandObstetricDopplerGuideline,NZMFMN,revisedSeptember2014,Page1

NEWZEALANDOBSTETRICDOPPLERGUIDELINE

ThisisaNewZealandguidelinefortheperformanceofobstetricDopplerexaminations.TheguidelineincorporatesdetailednotesoncorrectDopplertechnique,interpretationandreferencechartsforeachofcommonlyusedobstetricDopplerexaminations.Allhealthpractitionersinvolvedintheperformanceandinterpretationofobstetricultrasoundexaminationsareencouragedtousethisdocumentandincorporatetheprinciplesandreferencevaluesintotheirclinicalpractice.

Unalteredcopiesofthisguidelinemaybefreelyreproducedanddistributed.

Contributors:MartinNecas,DrEmmaParry,ProfessorLesleyMcCowan


WhichDopplerTestWhen?

SGAorIUGR UmbilicalarteryPI +

MeanuterinearteryPIattimeofdiagnossi(once)

UmbilicalarteryPIraised AddMCAPI+CPR Samedayreferraltospecialist

AddMCAPI+CPR Specialistreviewnow

Absentorreversedend-diastolicflow

Normal>34weeks AddMCAPI+CPR

Normal<34weeks Specialistreviewin1-2weeks

AtriskofearlyonsetmaternalhypertensivedisorderorSGA

MeanuterinearteryPIat20or24weeks

Suspectedfetalanaemia MCAPSV

MCDATwins NoevidenceofTTTS Bothtwins: UAPIfrom16weeks+MCAPSVfrom24weeks

Bothtwins: UAPI,MCAPI,MCAPSV,DVPI TTTS


UmbilicalArteryPulsatilityIndex(UAPI)Indications:

§ Suspectedorknownsmallforgestationalage(SGA)fetus§ TheestimatedfetalweightontheGROWchartis<10thpercentile§ TheestimatedfetalweightontheGROWchartisdroppingpercentilesby≥30%§ Theabdominalcircumferenceonthepopulationscanchartis<5thpercentile§ Discrepancy(≥30%)betweentheheadandabdominalcircumferencepercentilewithlowerACpercentile§ Maternalhypertensivedisorderse.g.preeclampsia§ Decreasedfetalmovements

Notindicated:§ Routinescreeningofnormalpregnancieswithnomaternalorfetalriskfactors

Howtoperformthetest:§ Performassessmentduringfetalquiescence§ AlwayskeepTIb<0.5ifpossibleoratleast<1byreducingtheacousticoutputpower§ IdentifyafreeloopofumbilicalcordoncolorDoppler§ UsehighcolorPRFtoavoidaliasingandconservativegaintoavoidcolorbleeding§ PositionthesamplevolumeinaportionofthecordcoursingparalleltoDopplerbeam§ AvoidsamplinginsuchawaythattheDopplerbeamisdirectedtowardsfetaleyes§ OptimisethespectralDopplerbaseline,PRFandsweepspeedtogetalargewaveform§ IftheEDVisnearthebaseline,ensurewallfilterissufficientlylowtodisplayEDV§ IfthePIiswithinnormalrange,onlysampleoneoftheumbilicalarteries§ IfthePIisabnormal,samplebothumbilicalarteriesandusethemorenormal(lower)value§ Iftheend-diastolicflowisabsentorreversed,commentonthisfindinginthereport

Howtointerpretthetest:§ >95thpercentileisabnormal

Commonpitfalls:§ PoorDopplerangleandpooroptimisationleadingtofuzzywaveformwhichishardtomeasure§ End-diastolicflowisnotvisualisedduetohighfiltersetting§ End-diastoleisnotwellvisualisedwhenEDVisnearbaselinebecauseofvenouscontamination-

readjustsamplingtoavoidcapturingadjacentUV

Reference:Ebbing,C.,Rasmussen,S.,&Kiserud,T.Middlecerebralarterybloodflowvelocitiesandpulsatilityindexandthecerebroplacentalpulsatilityratio:longitudinalreferencerangesandtermsforserialmeasurements.UltrasoundObstetGynecol,2007.30(3):p.287-96.


MiddleCerebralArteryPulsatilityIndex(MCAPI)Indications:

§ SGAwithabnormalUAPIatanygestationalage§ SGAwithnormalUAPIafter34weeksgestationalage§ MCDAtwingestationwithTTTS

Howtoperformthetest:

§ Performassessmentduringfetalquiescence§ AlwayskeepTIb<0.5ifpossibleoratleast<1byreducingtheacousticoutputpower§ StartwiththeBPDview§ Movecaudallytovisualisethebutterflyshapeofsuprasellarcisternsandthesphenoid§ Usethecoronalsuture/sphenoidalfontanelleasanacousticwindow§ Usehighdefinition(write)zoom§ ActivatecolorDopplertovisualisetheMCA§ AssesstheMCAwhichisclosertothetransducer§ MoveanteriorlyandanglebacktoaligntheMCAflowdirectionwiththeDopplerbeam§ Positionasmall(0.5-1mm)samplevolume2mmbeyondfromtheMCAorigin§ OptimisethespectralDopplerbaselineandPRFtogetalargewaveform

Howtointerpretthetest:

§ <5thpercentileisabnormal

Commonpitfalls:

§ PoorDopplerangleandpooroptimisationleadingtofuzzywaveformwhichishardtomeasure§ GatetooclosetoMCAoriginwheremultidirectionalcontaminationfromACAandPCoAoccurs§ SamplepositionedtooperipherallyintheMCAwherevelocitiesfall§ PCAmisidentifiedasMCA§ Poorvisualisationduetoinadequatezoom



CerebroplacentalRatio(CPR)Indications:

§ IfMCAPIassessmentwasperformed,theCPRshouldbecalculatedandrecorded

HowtocalculateCPR:

§ TheCPRisdefinedtheratioofMCAPIandUAPI


§ <5thpercentileisabnormal§ Note:ItcanbehelpfultoplottheMCAandCPRresultsonserialassessmentsto

determinethetrend



DuctusVenosusPulsatilityIndex(DVPI)Indications:

§ MarkedlyraisedUAPI(>>95th)andreducedMCAPIinpretermSGA§ MCDAtwingestationwithTTTSorselectiveIUGR


§ Performassessmentduringfetalquiescence§ AlwayskeepTIb<0.5ifpossibleoratleast<1byreducingtheacousticoutputpower§ SagittalandtransverseapproachesareacceptableaslongasDopplerangleis0-60degrees§ ActivatecolorDopplertoidentifyDVattheendofUV§ Enlargetheimage§ 0.5-1mmgateplacedintheinletofDV§ Setwallfilterlow,sweepspeedhigh§ OptimisethespectralDopplerbaselineandPRFtogetalargewaveform§ IfPI>95thpercentile,assessumbilicalveinforpulsatility


§ >95thpercentileisabnormal

CommonPitfalls

§ ColorPRFtoolowandgaintoohighleadingtodifficultyinDVidentificationamongstothervessels§ Samplesizetoolarge,leadingtocontaminationfromothervessels§ SamplenotplacedattheinletoftheDV§ AdjacenthepaticveinorceliacaxismisidentifiedasDV§ PoorDopplerangleandpooroptimisationleadingtofuzzywaveformwhichishardtomeasure§ FetalbreathingactivitymayresultinfalseimpressionofabsentAwave

Reference:Kessler,J.,Rasmussen,S.,Hnson,M.,&Kiserud,T.Longitudinalreferencerangesforductusvenosusflowvelocitiesandwaveformindices.UltrasoundObstetGynecol,2006.28:890-898.


MCAPeakSystolicVelocity(MCAPSV)Indications:

§ Maternal-fetalisoimmunisation§ Anysuspicionoffetalanaemia§ Unexplainedhydrops§ MCDAtwins>24weeksgestationalage§ MCDAtwinswithknownorsuspectedofTTTSorTAPS

Howtodoperformthetest:

§ Performassessmentduringfetalquiescence§ AlwayskeepTIb<0.5ifpossibleoratleast<1byreducingtheacousticoutputpowerwhenrequired§ StartwiththeBPDview§ Movecaudallytovisualisethebutterflyshapeofsuprasellarcisternsandthesphenoid§ Usethecoronalsuture/sphenoidalfontanelleasanacousticwindow§ Usehighdefinition(write)zoom§ ActivatecolorDopplertovisualisetheMCAandassesstheMCAwhichisclosertothetransducer§ MoveanteriorlyandanglebacktoaligntheMCAflowdirectionwiththeDopplerbeam§ Idealinterrogationangleis0degreesbut30degreesorlessisacceptable§ Positionasmall(0.5-1mm)samplevolume2mmbeyondfromtheMCAorigin§ OptimisethespectralDopplerbaselineandPRFtogetalargewaveform§ IftheDopplerangleisnotzero,anglecorrectionmustbeused§ IfPSV>1.5multiplesofthemedian(MoM),obtain3highqualitysamplesandusethehighestvalue


§ >1.5MoMisabnormal

CommonPitfalls:

§ PoorDopplerangleandpooroptimisationleadingtofuzzywaveformwhichishardtomeasure§ GatetooclosetoMCAoriginwheremultidirectionalcontaminationfromACAandPCoAoccurs§ SamplepositionedtooperipherallyintheMCAwherevelocitiesfall§ PCAmisidentifiedasMCA§ Failuretoangle-correctatanglesotherthan0leadingtounderestimationofPSV§ Poorvisualisationduetoinadequatezoom References:

Mari,G.NoninvasiveDiagnosisbyDopplerultrasonographyoffetalanemiaduetomaternalred-cellalloimmunization.NEnglJMed2000;342:9-14,p9-14.Mari,G.Middlecerebralarterypeaksystolicvelocityforthediagnosisoffetalanemia:theuntoldstory.UltrasoundObstetGynecol2005Apr;25(4):323-30.


MeanuterineArteryPulsatilityIndexIndications:

§ ScreenpatientsathighriskofearlypreeclampsiaorearlySGAat20or24weeks§ Ifabnormalat20weeks,repeatat24weeks§ EarlyonsetIUGR§ Currenthypertensivedisorderinpregnancy§ FullassessmentofsuspectedSGApregnancy


§ Locatethematernalanteriorsuperioriliacspineandanglemedially§ Alternativelyvisualizetheexternaliliacartery(EIA)§ TheuterinearteryistypicallyseencrossingtheEIAanteriorly§ SelectaportionoftheuterinearterywhichcoursesatafavourableDopplerangle0-60degrees§ OptimisethespectralDopplerbaselineandPRFtogetalargewaveform§ MeasuretherightandleftPIandcalculatethemeanvalue


§ >95thpercentileisabnormal§ Bilateralnotchingafter24weeksisabnormal

CommonPitfalls:

§ Failuretoidentifytheuterinearterybynotscanninginferiorlyenough

Reference:GomezO.,etal.Referencerangesforuterinemeanpulsatilityindexat11-41weeksofgestation.UltrasoundObstetGynecol2008;32:128-132.


QuickReferenceTables

UmbilicalArteryPIv MCAPIv

CerebroplacentalRatio(CPR)v

MeanUterineArteryPIö

CPR=MCAPI/UAPI MeanPI=(RTPI+LTPI)/2 >95thpercentileisabnormal <5thpercentileisabnormal <5thpercentileisabnormal >95thpercentileisabnormal

GestationWeeks

50thpercentile

95thpercentile

50thpercentile

5thpercentile

50thpercentile

5thpercentile

50thpercentile

95thpercentile

18 1.20 1.7919 1.25Ô 1.63Ô 1.15 1.7020 1.22Ô 1.59Ô 1.10 1.6121 1.15 1.46 1.05 1.5422 1.13 1.43 1.00 1.4723 1.10 1.40 0.96 1.4124 1.08 1.38 1.86 1.38 1.74 1.16 0.93 1.3525 1.06 1.35 1.94 1.44 1.85 1.24 0.89 1.3026 1.04 1.33 2.01 1.50 1.95 1.32 0.86 1.2527 1.02 1.31 2.06 1.55 2.05 1.40 0.84 1.2128 1.00 1.28 2.11 1.58 2.14 1.47 0.81 1.1729 0.98 1.26 2.15 1.61 2.21 1.53 0.79 1.1330 0.96 1.24 2.16 1.62 2.28 1.58 0.77 1.1031 0.94 1.21 2.16 1.62 2.32 1.62 0.75 1.0632 0.92 1.19 2.14 1.61 2.35 1.64 0.73 1.0433 0.90 1.16 2.10 1.58 2.36 1.65 0.71 1.0134 0.88 1.14 2.04 1.53 2.35 1.63 0.70 0.9935 0.86 1.11 1.96 1.47 2.32 1.60 0.69 0.9736 0.84 1.09 1.86 1.39 2.27 1.55 0.68 0.9537 0.81 1.06 1.75 1.30 2.19 1.48 0.67 0.9438 0.79 1.03 1.63 1.20 2.09 1.40 0.66 0.9239 0.77 1.00 1.49 1.10 1.97 1.29 0.65 0.9140 0.75Ô 1.07Ô 1.29ø 1.02ø 1.80ø 1.24ø 0.65 0.90

References:ÔAcharyaG,etal.Referencerangesforserialmeasurementsofbloodvelocityandpulsatilityindexattheintra-abdominalportion,andfetalandplacentalendsofumbilicalartery.UltrasoundObstetGynecol2005;26:162-169. v Ebbing,C.,Rasmussen,S.,&Kiserud,T.Middlecerebralarterybloodflowvelocitiesandpulsatilityindexandthecerebroplacentalpulsatilityratio:longitudinalreferencerangesandtermsforserialmeasurements.UltrasoundObstetGynecol,2007.30(3):p.287-96.øBaschatAA,GembruchU.ThecerebroplacentalDopplerratiorevisited.UltrasoundObstetGynecol2003;21:124-127.ö GomezO,etal.Referencerangesforuterinemeanpulsatilityindexat11-41weeksofgestation.UltrasoundObstetGynecol2008;32:128-132.


ObstetricDopplerreferencecharts


Reference:Ebbing,C.,Rasmussen,S.,&Kiserud,T.Middlecerebralarterybloodflowvelocitiesandpulsatilityindexandthecerebroplacentalpulsatility:longitudinalreferencerangesandtermsforserialmeasurements.UltrasoundObstetGynecol,2007.30(3):p.287-96.


Reference:Ebbing,C.,Rasmussen,S.,&Kiserud,T.Middlecerebralarterybloodflowvelocitiesandpulsatilityindexandthecerebroplacentalpulsatiliyratio:longitudinalreferencerangesandtermsforserialmeasurements.UltrasoundObstetGynecol,2007.30(3):p.287-96.


Reference:GomezO.,etal.Referencerangesforuterinemeanpulsatilityindexat11-41weeksofgestation.UltrasoundObstetGynecol2008;32:128-132.


Reference:Kessler,J.,Rasmussen,S.,Hnson,M.,&Kiserud,T.Longitudinalreferencerangesforductusvenosusflowvelocitiesandwaveformindices.UltrasoundObstetGynecol,2006.28:890-898.


References:Mari,G.NoninvasiveDiagnosisbyDopplerultrasonographyoffetalanemiaduetomaternalred-cellalloimmunization.NEnglJMed2000;342:9-14,p9-14.

Mari,G.Middlecerebralarterypeaksystolicvelocityforthediagnosisoffetalanemia:theuntoldstory.UltrasoundObstetGynecol2005Apr;25(4):323-30.

n zealand obstetric doppler uideline

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