VBG vs ABG (replacement of venous blood sample instead of arterial one for analysis of blood gases)

replacement of venous blood sample instead of arterial one for analysis of blood gases.

1. R. Amin Nejad; MD.
Anesthesiologist.

2. Peripheralvenoussample(obtainedby
venipuncture),
Centralvenoussample(obtainedfroma
centralvenouscatheter),ora
Mixedvenoussample(obtainedfromthe
distalportofapulmonaryarterycatheter)

3. Centralvenousbloodgaseshavebeenpreferred
becausetheircorrelationwitharterialblood
gasesisthemostwell-establishedbyresearch
andclinicalexperience.
Peripheralvenousbloodgaseshavebeen
studiedincriticallyillpatientsasanalternative
forpatientswhodonothavecentralvenous
access.
TavakolK,GhahramanpooriB,FararoueiM.PredictionofArterialBloodpHandPartialPressureof
CarbondioxidefromVenousBloodSamplesinPatientsReceivingMechanicalVentilation.JMedSignals
Sens2013;3:180.
ByrneAL,BennettM,ChatterjiR,etal.Peripheralvenousandarterialbloodgasanalysisinadults:are
theycomparable?Asystematicreviewandmeta-analysis.Respirology2014.
KellyAM,KlimS,ReesSE.Agreementbetweenmathematicallyarterialisedvenousversusarterialblood
gasvaluesinpatientsundergoingnon-invasiveventilation:acohortstudy.EmergMedJ2013.

4. CengizM,UlkerP,MeiselmanHJ,BaskurtOK.Influenceoftourniquetapplicationon
venousbloodsamplingforserumchemistry,hematologicalparameters,leukocyte
activationanderythrocytemechanicalproperties.ClinChemLabMed2009;47:769.

5. Venousoxygentension(PvO2)
Carbondioxidetension(PvCO2)
Acidity(pH)
Oxyhemoglobinsaturation(SvO2)
Serumbicarbonate(HCO3)concentration

6. ●PvCO2,venouspH,andvenousserumHCO3
concentrationareusedtoassessventilationand/or
acid-basestatus.
●SvO2isusedtoguideresuscitationduringsevere
sepsisorsepticshock,aprocesscalledearlygoal-
directedtherapy.
●PvO2hasnopracticalvalueatthistime.Itisnot
usefulinassessingoxygenationbecauseoxygen
hasalreadybeenextractedbythetissuesbythe
timethebloodreachesthevenouscirculation.

9. ThepHisusually0.03to0.05pHunitslower
ThePCO2isusually4to5mmHghigherand
LittleornoincreaseinserumHCO3
than the arterial one
MalinoskiDJ,ToddSR,SloneS,etal.Correlationofcentralvenousandarterialbloodgas
measurementsinmechanicallyventilatedtraumapatients.ArchSurg2005;140:1122.
WalkeyAJ,FarberHW,O'DonnellC,etal.Theaccuracyofthecentralvenousbloodgasforacid-
basemonitoring.JIntensiveCareMed2010;25:104.

10. RamakrishnaMN,HegdeVD,KumarswamyGN,etal.Impactofpreoperativemildrenal
dysfunctiononshorttermoutcomeinisolatedCoronaryArteryBypass(CABG)patients.IndianJ
CritCareMed2008;12:158.
LadakisC,MyrianthefsP,KarabinisA,etal.Centralvenousandmixedvenousoxygensaturationin
criticallyillpatients.Respiration2001;68:279.
TsaousiGG,KarakoulasKA,AmanitiEN,etal.Correlationofcentralvenous-arterialandmixed
venous-arterialcarbondioxidetensiongradientwithcardiacoutputduringneurosurgical
proceduresinthesittingposition.EurJAnaesthesiol2010;27:882.

11. ThepHisapproximately0.02to0.04pHunits
lower
ThevenousserumHCO3concentrationis
approximately1to2meq/Lhigher
ThevenousPCO2isapproximately3to8
mmHghigher
than the arterial one
GokelY,PaydasS,KoseogluZ,etal.Comparisonofbloodgasandacid-basemeasurementsinarterialandvenousbloodsamplesinpatientswithuremicacidosisanddiabeticketoacidosisintheemergencyroom.AmJNephrol2000;20:319.
BrandenburgMA,DireDJ.Comparisonofarterialandvenousbloodgasvaluesintheinitialemergencydepartmentevaluationofpatientswithdiabeticketoacidosis.AnnEmergMed1998;31:459.
MalateshaG,SinghNK,BharijaA,etal.ComparisonofarterialandvenouspH,bicarbonate,PCO2andPO2ininitialemergencydepartmentassessment.EmergMedJ2007;24:569.
ChuYC,ChenCZ,LeeCH,etal.Predictionofarterialbloodgasvaluesfromvenousbloodgasvaluesinpatientswithacuterespiratoryfailurereceivingmechanicalventilation.JFormosMedAssoc2003;102:539.
KellyAM,KyleE,McAlpineR.VenouspCO(2)andpHcanbeusedtoscreenforsignificanthypercarbiainemergencypatientswithacuterespiratorydisease.JEmergMed2002;22:15.
KellyAM,McAlpineR,KyleE.VenouspHcansafelyreplacearterialpHintheinitialevaluationofpatientsintheemergencydepartment.EmergMedJ2001;18:340.

12. ABG pH PCO2 HCO3
VBG (CVC)+ (0.03-0.05)-(4-5 mmHg)No change
VBG (MVC)+ (0.03-0.05)-(4-5 mm Hg)No change
VBG (PVC)+(0.02-0.4)-(3-8 mm Hg)-(1-2 meq/L)

14. CliniciansshouldbewaryofVBGresultsand
preferentiallyobtainanABGinhypotensive
patients.
Periodiccorrelationofthevenous
measurementswitharterialmeasurements
shouldbeperformedwhenevervenous
measurementsareusedforserialmonitoring.

15. RichardTreger,ShahriarPirouz,NaderKamangar,Dalila
Corry;Arterialvsvenousbloodgasdifferencesduring
hemorrhagicshock;WorldJCritCareMed.May4,2014;
3(2):55–60.

16. PeripheralorcentralvenouspH,PCO2and
bicarbonatecanreplacetheirarterial
equivalentsinmanyclinicalcontextsthatare
encounteredintheICU.