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Variation Assessment: a Comparaison with the PiCCO Technique
Taous-Meriem Laleg-Kirati, Claire Médigue, Yves Papelier, François Cottin, Andry van de Louw
To cite this version:
Taous-Meriem Laleg-Kirati, Claire Médigue, Yves Papelier, François Cottin, Andry van de Louw.
Validation of a New Method for Stroke Volume Variation Assessment: a Comparaison with the PiCCO Technique. [Research Report] RR-7172, INRIA. 2010, pp.22. �inria-00429496v3�
a p p o r t
d e r e c h e r c h e
N0249-6399ISRNINRIA/RR--7172--FR+ENG
Validation of a New Method for Stroke Volume Variation Assessment: a Comparison with the
PiCCO Technique
Taous-Meriem Laleg-Kirati — Claire Médigue — Yves Papelier — François Cottin — Andry Van de Louw
N° 7172
Janvier 2010
Centre de recherche INRIA Paris – Rocquencourt
PiCCO Tehnique
Taous-Meriem Laleg-Kirati
∗
, ClaireMédigue
†
, YvesPapelier
‡
,
FrançoisCottin
§
, Andry Van de Louw
¶
Thème: Observation, modélisationet ommandepourlevivant
Équipe-ProjetSISYPHE
Rapportdereherhe n°7172Janvier201022pages
Abstrat: Thispaperproposesanovel,simpleandminimallyinvasivemethod
for strokevolume variation assessmentusing arterial blood pressure measure-
ments. Thearterialbloodpressuresignalisreonstrutedusingasemi-lassial
signalanalysismethodallowingtheomputationofaparameter,alledtherst
systoli invariant IN V S1. Weshowthat IN V S1 is linearlyrelated to stroke
volume. Tovalidate this approah, astatistial omparaisonbetweenIN V S1
andstrokevolumemeasuredwiththePiCCOtehniquewasperformedduringa
15-mnreordingin21mehaniallyventilatedpatientsinintensiveare. In94%
ofthewhole reordings,astrongorrelationwasestimatedbyross-orrelation
analysis (mean oeient=0.9) and linearregression (mean oeient=0.89).
One the linear relation had been veried, a Bland-Altman test showed the
verygoodagreementbetweenthetwoapproahesand theirinterhangeability.
Fortheremaining 6%,IN V S1 andthe PiCCOstrokevolume were notorre-
lated at all, and this disrepany, interpretedwith the help of meanpressure,
heartrateandperipheralvasularresistanes,wasinfavorofIN V S1.
Key-words: Arterial blood pressure, rst systoli invariant, PiCCO, semi-
lassialsignalanalysis,strokevolumevariation
∗
Taous-MeriemLaleg-KiratiiswithINRIABordeauxSud-Ouest,MAGIQUE-3Dprojet
team,UFRSienes,BâtimentB1,UniversitédePauetdesPaysdel'AdourBP1155,64013
Pau,Frane,(e-mail:Taous-Meriem.Laleginria.fr).
†
ClaireMédigueiswithINRIA-Roquenourt,B.P.105,78153LeChesnayedex,Frane,
(e-mail:Claire.Medigueinria.fr).
‡
Yves Papelieriswith EA3544 EFMHpital Antoine Bélère 92141, Clamart,Frane,
(e-mail:yves.papelierkb.u-psud.fr)
§
FrançoisCottiniswithUnitédeBiologieIntégrativedesAdaptationsàl'Exerie(IN-
SERM902EA3872,Genopole),91000Evry,Frane,(e-mail:franois.ottinbp.univ-evry.fr)
¶
AndryVandeLouwiswithIntensiveCareUnit,CentreHospitalierSud-Franilien,91014
Evry,Frane,(e-mail:andry.vandelouwh-sud-franilien.fr)
omparaison ave le PiCCO
Résumé: Cet artileproposeune nouvelleméthodepourl'estimation duvo-
lumed'ejetionsystolique par desmesuresde pressionartérielle. Le signalde
pressionestreonstruitàl'aided'uneméthoded'analysesemi-lassiquepermet-
tant le alul d'un paramètre, appelé le premier invariantsystolique IN V S1.
Onmontre que IN V S1 est linéairementrelié auvolume d'ejetionsystolique.
An de valider ette approhe, une omparaison statistique entre IN V S1 et
levolumed'ejetionsystolique mesuréparlatehniquePiCCOaétéeetuée
pourunenregistrementde15minutespour21patientsméaniquementventilés
et ensoinsintensifs. Pour94%de l'enregistrementomplet,uneforte orréla-
tionaétéestimée parune analyseross-orrélation(oeientmoyen=0.9)et
une regressionlinéaire(oeient moyen =0.89). Une fois larelation linéaire
vériée,untestdeBland-Altmanamontréunebonneorrespondaneentreles
deux approhes et leur interhangeabilité. Pourles 6% restant, IN V S1 et le
volumed'éjetionaluléparPiCCOn'ontpasétéorrélés,et ettediérene,
interprétée à l'aide de la pression moyenne, de la fréquene ardiaque et des
résistanesvasulairespériphériquesaétéenfaveurdeIN V S1.
Mots-lés: Pressionartérielle,premierinvariantsystolique,PiCCO,analyse
semi-lassiquedusignal,variationsduvolumed'éjetion
Contents
1 Introdution 3
2 Materialsand Methods 5
2.1 Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Dataaquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 Signalanalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4 Statistialanalysis . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3 Results 11 3.1 Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Cross-orrelationanalysis . . . . . . . . . . . . . . . . . . . . . . 12
3.3 Linearregression . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.4 Bland-Altmanmethod . . . . . . . . . . . . . . . . . . . . . . . . 13
4 Disussion 15
1 Introdution
Hemodynami monitoring is ruial for ritial are patient management. A
reentinternationalonsensusonferenereommendedagainsttheroutineuse
ofstati preloadedmeasurementsalone topredituidresponsiveness[2℄, and
dynami assessmentnowseems moreuseful. Several studieshavedoumented
the ability of respiratory stroke volume variation (SV V) to predit the uid
responsiveness in hemodynamially ompromised patients[8℄-[13℄. Measuring
respiratorySV V requiresaontinuousmonitoringofstrokevolume(SV)whih
anbeobtainedusinginvasiveornon-invasivemethods. Currentinvasivemeth-
ods used havethe disadvantage of requiring theinsertion of a entral venous
atheter and the alibration of the ardia output measure with a old iso-
tonisodiumhloridebolus(PiCCOtehnology)[3℄oralithiumhloridebolus
(LiDCO tehnology) [9℄. An alternative method, whih does not require ve-
nous atheter insertionor alibrationhas been proposed (Flotra Vigileo) [5℄,
but severallinial studieshavepointedoutitspooragreementwithreferene
tehniques[12℄,[16℄. Esophagealeho-doppleristhemainnon-invasivemethod,
alulating aorti blood ow from the eho-derived aorti diameter and the
doppler-derivedaortibloodveloity[11℄. Nevertheless,thistehniquehaspo-
tentialontraindiations,suhasesophagealvariesoresophagealsurgery,and
several limitations: for instane, it measures theblood owin thedesending
aorta and not the whole ardia output. Moreover,the preisionof themea-
surement depends on aurate probe positioning, whih is not always easyto
obtain[4℄. Thus,eahoftheabovemethodshasitsowndrawbaks,andthereis
stillaneedforaneasilyappliable,minimallyinvasive,aurateandaordable
method toestimateSV V.
Due to thefat that Arterial Blood Pressure (ABP) anbe measured us-
ingminimallyinvasiveornoninvasivemethods,theideaofestimatingSV from
ABP hasaptured sientistsfora longtime. Thus, manymethods havebeen
developedand whoseobjetiveisto nd arelation betweenoneorseveralpa-
rameters haraterizing the shape of the pressure and SV or ardia output
(CO),seeforinstane[7℄,[15℄,[22℄,[23℄andthereferenesquotedthere. These
methods, whih are based on some models of systemi irulation, are alled
pulseontourmethods. Aomparisonbetweensomeofthepulseontourmeth-
ods has been proposed in [1℄, [26℄, [27℄, [29℄. The simplest model supposes a
proportionalitybetweenCO and the Mean Arterial Pressure (M AP). Other
approahes, based onwindkessel models, link SV to dierent lumped param-
eters suh as pulse pressure, the systoli and diastoli pressures[7℄. However
theseapproahesonsiderthearterialsystemasalumpedsystemwhihappears
notsuientlyaurate. So, othermethods resultingfromdistributed arterial
modelsusethepressureareasothatSV isoftensupposedtobeproportionalto theareaunderthesystolipartofthepressureurve. Corretedversionsofthis
relationhavebeenalsoproposed[15℄. However,thisapproahrequiresdeteting
theendofthesystolewhihisompletelynontrivial,partiularlyinperipheral
ABP waveforms. Moreover, approahes taking into aountthe nonlinear as-
pets of the arterial system have been proposed, for example modelow [28℄,
butsomestudieshaverevealedthepooreieny ofthis methodin anumber
ofases[24℄.
In this paper we introdue a novel tehnique for SV V assessment using
ABPmeasurements. Thismethod isbasedontheanalysis ofABPwithanew
signal analysis method that was reently proposed in [21℄, and alled Semi-
Classial Signal Analysis (SCSA). The new spetral parameters provided by
SCSA,eigenvaluesandinvariants,havealreadygivenpromisingresultsinsome
otherappliations,assummarized inthefollowing.
On the one hand,weassessed their ability to disriminate between dier-
entsituations. Intherstsituation,nineheartfailure subjetswereompared
to nine healthy subjets. In the seond situation, eight highly t triathletes
were ompared before and after training. SCSA parameters always provided
moresigniant results than lassial parameters, regardingtemporal as well
asspetralparameters([20℄, [21℄). On theotherhand,wetested theabilityof
theinvariants to represent physiologialparameters of great interest, partiu-
larlySV V,in twowell-knownonditions: thehead-up 60degreestilt-testand
the handgrip-test [21℄. Let us fous on the rst invariants. The rst global
invariant(IN V1) is,by denition,themeanvalueof theABPsignal,whihis
astandardparameterinlinialpratie. Therstsystoli(IN V S1)anddias-
toli(IN V D1)invariantsarelessobvious. Theyresultfromthedeomposition ofthepressureintoitssystolianddiastoliparts. Inpartiular,IN V S1orre-
spondsto theintegraloftheestimated systolipressurewith SCSA.Referring
to the pulse ontour method stating that the area under the systoli part of
thepressureurveisproportionaltoSV asdesribedabove,oneanshowthat IN V S1 variationsgiveinformationonSV V.
WestudyinthispapertheorrelationbetweenIN V S1andmeasuredSV V
using areferene method; thePiCCO tehnique. ThePiCCO tehnique uses
the pulse ontour method with a alibration by a transpulmonary thermodi-
lution and is onsidered areliable tehnique. In what follows, we presentthe
experimentalprotooland reallsomebasiaspetsoftheSCSAmethod. We
introdueIN V S1anditsrelationtoSV V. Then,wepresentstatistialresults
on21patients'reordings.
2 Materials and Methods
This prospetivestudywasonduted in the16-bedmedial-surgialintensive
areunit(ICU)oftheSud-FranilienGeneralHospital(Evry,Frane).
2.1 Patients
Inlusionriterion: allmehaniallyventilatedpatientswhoseardia
output was ontinuously monitored with a transpulmonary thermodilu-
tionatheter(PiCCO,PulsionMedialSystems,Munih,Germany)were
inluded,exeptthosesatisfyingthefollowingexludingriteria. PiCCO
isroutinely used in this unit to monitorhemodynamially ompromised
patients.
Exlusionriteria: patientspresentingardiaarrhythmiasorbreath-
ing spontaneously were exluded beause the SVV is not appliable for
suhpatients.
Protool: all patients were sedated with midazolam and fentanyl in
dosages that were titrated to ahieve full adaptation to the ventilator.
Ventilatorsettingswereasfollows: volumeassist-ontrolmode;tidalvol-
ume (Vt), 6ml/kg ideal body weight; breathing rate, 20 yles/minute;
inspiratory/expiratoryratio,
1
2; andF iO2adjusted to maintaintransu-
taneousoxygensaturationinblood94%. Positiveend-expiratorypressure
(PEEP) wasset at 5cm H2O but somehypoxemi patientsrequired an
inreaseinPEEP to 10m H2Oduring thedataaquisition,to improve
arterial oxygenation. The inrease in PEEP was left to the disretion
oftheattending physiian, aswellasthe adaptationofvasoativedrugs
dosages,adjusted to maintainan adequateirulatorystatus during the
protool.
2.2 Data aquisition
One-leadeletroardiogram,arterialpressure,andrespiratoryowsignalswere
reorded during a15-min period using aBiopa 100system (Biopasystems,
Goleta, CA, USA). All data were sampled at 1000Hz and stored on a hard
disk. Cardiaoutputwasalibratedjustbeforethedataaquisitionwithaold
isotoni sodium hloride bolus of 20 ml. Then, CO and peripheral vasular
resistanes(P V R)weredeliveredevery30seondsduring the15-minperiod.
2.3 Signal analysis
SignalproessingwasperformedusingtheSilab andMatlabenvironmentsat
the Frenh National institute for Researh in Computer Siene and Control
(INRIA-Sisyphe team).
A Semi-ClassialSignal Analysis method
Inthissetion,weintroduetheSCSAtehniqueandsomeresultsofitsappli-
ationtoABPanalysis. WealsoshowtherelationbetweenIN V S1 andSV V.
TheSCSApriniple Lety:t7−→y(t)bearealvaluedfuntionrepresenting thesignaltobeanalyzedsuhthat:
y∈L11(R), y(t)≥0, ∀t∈R,
∂my
∂xm ∈L1(R), m= 1,2, (1)
with,
L11(R) ={V| Z +∞
−∞
|V(t)|(1 +|t|)dt <∞}. (2)
The main ideain the SCSAonsists in interpreting the signaly asa mul-
tipliation operator, φ → y.φ, on somefuntion spae. Then, instead of the
standard Fourier Transform, we use the spetrum of a regularized version of
thisoperator,knownas theShrödingeroperatorin L2(R), forthe analysisof y:
H(h;y) =−h2d2
dt2 −y, (3)
forasmall h > 0. TheSCSA method isbettersuited to theanalysis of some
pulseshapedsignalsthantheFourierTransform[21℄.
Inthisapproah,thesignalisapotentialoftheShrödingeroperatorH(h;y).
Weareinterestedinthespetralproblemofthis operatorwhih isgivenby:
−h2d2ψ
dt2 −yψ=λψ, t∈R, (4)
whereλ, λ∈Randψ,ψ∈H2(R)1arerespetivelytheeigenvaluesofH(h;y)
andtheassoiatedeigenfuntions. Underequation(1),thespetrumofH(h;y)
onsistsof:
aontinuousspetrumλ≥0,
adisretespetrumomposedofnegativeeigenvalues. Thereisanon-zero,
nitenumberNh ofnegativeeigenvaluesoftheoperatorH(h;y). Weput λ=−κ2nh withκnh >0 andκ1h> κ2h >· · · > κnh,n= 1,· · ·, Nh. Let
ψnh,n= 1,· · ·, Nh betheassoiatedL2-normalizedeigenfuntions[21℄.
TheSCSAtehniqueonsistsinreonstrutingthesignalywiththedisrete
spetrumofH(h;y)usingthefollowingformula:
yh(t) = 4h
Nh
X
n=1
κnhψnh2 (t), t∈R. (5)
Here,theparameterhplaysanimportantrole. Ashdereases,theapproxi-
mationofthesignalimproves. However,ashdereases,thenumberofnegative
eigenvaluesNh inreases and hene the time required to perform the ompu-
tation inreases. So, in pratie, what weare looking foris a valueof h that
providesasuientlysmallestimationerrorwithareduednumberofnegative
eigenvalues. Wesummarizethemain stepsforreonstruting asignalwiththe
SCSAasfollows[21℄:
1H2(R)denotestheSobolevspaeoforder2
1. Interpret the signal to be analyzed y as a potential of the Shrödinger
operatorH(h;y)(3);
2. omputethenegativeeigenvaluesandtheassoiatedL2-normalizedeigen- funtionsofH(h;y);
3. omputeyhaordingto equation(5);
4. lookforavalueofhtoobtainagoodapproximationwithasmallnumber ofnegativeeigenvalues.
ABP analysiswith the SCSA Now,weintroduesomeresultsontheap-
pliationoftheSCSAtoABPanalysis. WedenotebyP theABPsignalandPˆ
itsestimationwiththeSCSAsuhthat:
Pˆ(t) = 4h
Nh
X
n=1
κnhψ2nh(t), (6)
where−κ2nh,n= 1,· · ·, Nh aretheNh negativeeigenvaluesoftheShrödinger operator H(h;P)andψnh theassoiatedL2−normalizedeigenfuntions.
The ABP signal wasestimated for several values of the parameter h and
heneNh. Fig.1illustratesmeasuredandestimatedpressuresforonebeatofan ABPsignalandtheestimatederrorwithNh= 9. Signalsmeasuredattheaorta
(invasively)andatthenger(noninvasively)respetivelywereonsidered. We
pointoutthat5to9negativeeigenvaluesaresuientforagoodestimationof anABPbeat[17℄,[19℄.
Oneappliation of the SCSA to ABP signals onsists in deomposing the
signal into its systoli and diastoli parts. This appliation was inspired by
a redued model of ABP based on solitons solutions of a Korteweg-de Vries
(KdV) equation 2
proposed in [10℄, [18℄. As desribed in [17℄, [21℄, the idea
onsists in deomposing (6) into twopartial sums: the rst one,omposed of
the Ns (Ns = 1,2,3 in general) largest κnh and the seond omposed of the
remainingomponents. Then,therstpartialsumrepresentsrapidphenomena
that predominateduring the systoliphase andthe seondone desribesslow
phenomenaofthediastoliphase. WedenotebyPˆsandPˆd thesystolipressure
andthediastolipressurerespetivelyestimatedwiththeSCSA.Thenwehave:
Pˆs(t) = 4h
Ns
X
n=1
κnhψ2nh(t), (7)
Pˆd(t) = 4h
Nh
X
n=Ns+1
κnhψnh2 (t). (8)
Fig.2showsmeasuredpressureandestimatedsystolianddiastolipressures
respetively. WenotiethatPˆsandPˆdarerespetivelyloalizedduringthesys- toleandthediastole.
2
Solitonsaresolutionsofsomenon-linearpartialderivativeequationsliketheKdVequation
1.6 1.8 2 2.2 2.4 2.6 2.8 3 50
55 60 65 70 75 80 85 90 95
t (s)
Arterial blood pressure (mmHg)
Estimated pressure Measured pressure
1.6 1.8 2 2.2 2.4 2.6 2.8 3
0 0.5 1 1.5 2 2.5
t (s)
Relative error (%)
(a)Aorta
1.6 1.8 2 2.2 2.4 2.6 2.8 3
50 60 70 80 90 100 110 120 130 140
t (s)
Aretrial blood pressure (mmHg)
Estimated pressure Measured pressure
1.6 1.8 2 2.2 2.4 2.6 2.8 3
0 0.5 1 1.5 2 2.5 3
t (s)
Relative error (%)
(b)Finger
Figure1: Estimationofthepressureattheaorta andthengerlevelwiththe
SCSAandNχ= 9. Ontheleft,theestimatedandmeasuredpressures. Onthe
right,therelativeerror
1.6 1.8 2 2.2 2.4 2.6 2.8 3
0 10 20 30 40 50 60 70 80 90 100
t (s)
ABP (mmHg)
Reconstructed systolic pressure Measured pressure
(a)
1.6 1.8 2 2.2 2.4 2.6 2.8 3
30 40 50 60 70 80 90 100
t (s)
ABP (mmHg)
Reconstructed diastolic pressure Measured pressure
(b)
Figure2: (a)Estimatedsystolipressure,(b)Estimateddiastolipressure