hemodynamic monitoring · 2019-08-09 · intra-arterial blood pressure indications • beat-to-beat...

HemodynamicMonitoring

Albert R. Robinson III, M.D.Associate Professor

Department of AnesthesiologyThe University of Florida

College of Medicine

Josh Sappenfield, M.D.Assistant Professor

Department of AnesthesiologyThe University of Florida

College of Medicine

Objectives

• Understandtheimportanceofmonitoring• Reviewtheindications,contraindications,andcomplications forthemostwidelyusedAnestheticmonitors

• Learntheimportanceofinvasivemonitors:arterialcatheter,centralvenouscatheter,andpulmonarycatheter

Monitors

“Nomonitoristherapeuticinitselfbutrequirestheskillandvigilanceofatrainedobservertointerprettheinformationinthecontextofthe

ever-changingclinicalpicture.”

Euliano T,Gravenatein JS.etal.EssentialAnesthesia:FromSciencetoPractice.Chapter7:Monitoring.CambridgeUniversityPress,NewYork,2011.

MonitoringImportance

• Monitoringprovidesanearlywarningofadversechangesortrendsbeforeirreversibledamageoccurs

• Monitoring– reflectsphysiologichomeostasis– allowspromptrecognitionofresponsestotherapeuticinterventions

– allowspromptrecognitionofadversechanges.• Whatisthemostimportantmonitor?– Vigilance!

Stoelting RK,MillerRD.BasicsofAnesthesia.4th Ed.Chapter16.Monitoring.ChurchillLivingstone,Philadelphia,2000.

Monitors• VigilantPhysicians(Subjectivedata)– Monitors– (Visual,Tactile,Auditory,Olfactory)

• StandardMonitoringEquipment(ObjectiveData)• PulseOximetry• Capnography• BodyTemperature• ECG• SystemicBloodPressure

BuildingBlocksofMonitoring

“Allmonitoringbuildsonold-fashionedinspection,auscultation,andpalpation.”


MonitoringthatRequiresNoInstrumentation

• Inspection– Skin– NailBeds–Mucousmembranes– Surgicalfield

– BodilyMovement

– Eyes

MonitoringthatRequiresNoInstrumentation

• Inspection– Skin (Istherenormalcapillaryrefill?Delayed

returnsuggestsabnormalityinregionalorsystemiccirculation)

• Palpation– Skin (Isthepatientwarmorcoldandclammy)– Pulse (Presence/Absenceofpulse)– Skeletalmuscle (Aremusclesfasciculating)

• Percussion– Gastric (Isthereabdominaldistension)

• Auscultation– Chest (Listenforbreathsoundsoverbothlung

field,isthereparadoxicalbreathing)– Heart (Aresoundsmuffled,ormurmurspresent)

MinimalMonitoringStandards

• TheAmericanSocietyofAnesthesiologist(ASA)callsforstandardmonitorsforallpatientsundergoinggeneralanesthesia– Oxygenation(inspiredgasandsaturationofarterialblood(SpO2))

– Ventilation(capnography andclinicalassessment)– Circulation(ECG,arterialbloodpressure)– Temperature

Electrocardiogram(ECG)

• Providesinformationon– cardiacarrhythmias– myocardialischemia/infarction– electrolytechanges,particularlypotassium

• ECGisnot ameasureofheartfunction• ECGreflectsonlytheelectricalactivitiesoccurringintheheart

Stoelting RK,MillerRD.BasicsofAnesthesia.4th Ed.Chapter16.Monitoring.ChurchillLivingstone,Philadelphia,2000.

ECG5-LeadPlacement

• “SnowontheGrass”→WhiteECGelectrodetorightshouldovergreenECGelectrode

• “Smokeoverfire”→BlackECGelectrodetoleftshouldoverredECGelectrode

• BrownECGelectrodeattheV5position(Leftanterioraxillarylinebetweenfourthandfifthintercostalspace)


ECG

• LeadV5isthemostsensitiveleadfordetectingischemia

• LeadIIisthemostsensitiveleadfordetectingarrhythmias

• PwavesarebestseenonLeadII– bestenablesonetoobservethecardiacrhythm.

PulseOximetry• Assesstheoxygenationofblood• Reduced(ordeoxygenated)hemoglobin(Bluish)• Oxygenatedhemoglobin(Red)• Howitworks?– Aprobesendlightimpulsesintoafingerandcollectsthelightthatpassthroughit.

– Theunitsestimatestheproportionofoxyhemoglobin toreducedhemoglobin

• SpO2– thesaturationbasedonpulseoximetry• SaO2– thesaturationobtainedfromdirectarterialbloodsample

Pulseoximetry (cont)

CorrelationofSpO2 toarterialpartialpressureofoxygen(PaO2)

SpO2 PaO2

100% 100mmHgorhigher

90% 60mmHg

80% 50mmHg

60% 30mmHg

BloodPressure(BP)Monitoring• Thelateralpressureexertedbythecontainedbloodonthewallsofthevesselsisarterialpressure.

• FactorscontrollingbloodpressureincludeØ Hormonalmechanisms(i.e.catecholamines,renin-angiotensin,antidiuretichormone,atrialnatriureticpeptide

ØCentral&autonomicnervousfunctionØPeripheralvascularresistanceØCardiacoutput

• BPmonitoringiscommonlyperformedØ Indirectly – noninvasivecuffaroundextremityØDirectly – insertingcatheterintoartery

Barash PG,CullenBF,Stoelting RK.ClinicalAnesthesia(5th ed).Ch.24:MonitoringtheAnesthetizedPatient.LippincottWilliams&Wilkins.Philadelphia.2006.

BP- NoninvasiveMonitoring

• MechanicaldeformationfromthebloodpressurecuffofanarteryleadstothecreationofKorotkoff soundsresultfromturbulentflow

• TheappearanceofthefirstKorotkoff soundisthesystolicbloodpressure

• ThedisappearanceoftheKorotkoff soundsignalsthediastolicbloodpressure.

BloodPressure

• SystolicBloodPressure(SBP)– Pressurewhichejectedbloodwillovercometoperfusevesselsdistally

• DiastolicBloodPressure(DBP)– Pressureunderwhichthebloodflowwillbelaminar

• PulsePressure=SBP- DBP• MeanArterialBloodPressure(MAP)– Timeweightedaverageofarterialpressuresduringapulsecycle

– MAP=[SBP+(2xDBP)]/3

NIBPBladderCuff• AmericanHeartAssociationrecommends

– Bladderwidth– approximately40%ofthecircumferenceoftheextremity

– BladderLength– sufficienttocircleatleast60%oftheextremity

• Falselylowestimatesoccur:– afterquickdeflation– whentheextremityisabovetheheart– whencuffsaretoolarge

• Falselyhighestimatesoccurwhen:– cuffsareappliedtooloosely– whentheextremityisbelowheartlevel– whencuffsaretoosmall


NoninvasiveBloodPressureMonitoringProblems

• Hematomasresultsduetoincreasevenouspressureafterfailuretodeflatethecuff

• Delayedcuffdeflationcanresultsfromshiveringandtremors

• Ulnarneuropathycanoccurduetocompressionoftheulnarnerve

InvasiveMonitors

• Intra-arterialbloodpressure• Centralvenouspressure• Pulmonaryarterycatheters(Swan-Ganz)• Transesophagealechocardiography(TEE)

Intra-arterialBloodPressureIndications

• Beat-to-beatmonitoring• Expectedrapidchangesinhemodynamicstability

• Inducedhypotension,acutehypotension• Reliableaccessforanalysisofarterialbloodgases,pH,and/orelectrolytes

• Inabilitytoachievenoninvasivemonitoring• Vasoactivedrugs• Sepsis

SystemicBloodPressureMonitoringSites

• ArterialCannulation Sites– Aorta– Axillaryartery– Brachialartery– Radialartery - mostpopularsiteduetopresenceofacollateralbloodsupplyandaccessibility

– Ulnarartery– Femoralartery– Dorsalis pedis artery

ArterialBloodPressureMeasurement

• Wavereflectiondistortsthearterialpressurewaveform,leadingtoanexaggerationofsystolicandpulsepressure,asapulsemovesperipherallythroughthearterialtree

• Forexample,dorsalpedis arterypressuresareusuallyhigherthanaorticsystolicpressurebecauseoftheformer’smoredistallocation(seeFigure)

Changesinarterialbloodpressurewaveformconfigurationasawaveformmovesperipherally

ShahN,BedfordRF:Invasiveandnoninvasivebloodpressuringmonitoring.In:clinicalMonitoring:PracticalApplicationsinAnesthesiaandCriticalCareMedicine.LakeCL,HinesRL,Blitt CD[editors].WBSanders,Philadelphia,2001,p.182.

ArterialPressureWaveform

• Rateofupstrokeindicatescontractility

• Rateofthedownstrokeindicatesperipheralvascularresistance

• Dicrotic notchreflectstheclosureoftheaorticvalve

• ThefartheroutthedicroticnotchthelowertheSVRorperipheralvascularresistance

ComplicationsofIntra-arterialBPCatheterization

• Hematoma• Bleeding• Vasospasm• ArterialThrombosis• DistalEmboli• InfectionandNecrosis• Airembolism• Lossofdigits• Unintentionalintraarterial druginjection• Pseudoaneurysm• Damagetoadjacentnerves

CentralVenousAccessIndications

• Monitoringcentralvenouspressure(CVP)• Rapidadministrationoffluidtotreathypovolemiaandshock(i.e.acutehemorrhaging)

• Infusionsofdrugs• Long-termIVFeeding(i.e.Hyperalimentation)• Aspirationofairemboli• InsertionofTranscutaneouspacingleads• VenousAccessinpatientswithpoorperipheralveins

InternalJugular(IJ)CentralVenousMonitoring

• RightIJveinisthepreferredsiteforcannulation– Highsuccessrateinbothadultsandchildren– Predictableanatomy– Accessiblefromtheheadoftheoperatingtable

• LeftsideIJislessdesirablebecauseofpotentialdamagetothe– Thoracicduct– Challengeofplacingcatheterthroughthejugular-subclavianjunction.


CVCPlacementSitesAdvantages Disadvantages

R Internal jugular vein Good landmarksPredictable anatomyAccessible from head of OR table

Carotid artery punctureTrama to brachial plexus

L Internal jugular vein Same as above Same as aboveThoracic duct damage

Subclavian vein Good landmarksRemains patent despite hypovolemiaPatient comfort when awake

Pneumothorax

External jugular vein Superficial location Often difficult to thread catheter into the central circulation

Femoral vein Good landmarksAccessible in low flow state

Risk of local hematoma

Antecubital vein Safety Often difficult to thread into the central vein

CVCContraindications

• Anticoagulants• Ipsilateral carotidendarterectomy• Fungating tricuspidvalvevegatations• Renalcelltumorextensionintotherightatrium

• ContralateralPneumothorax

CVPWaveform• Centralvenouspressureparallelsrightatrialpressure,whichisamajordeterminantofvenousblood.

• Normalpressuresmightrangefrom-2to12mmHginaspontaneouslybreathingpatient.

• Pressuresof6to15mmHg(ormorewithhighpeakinspiratorypressures)canbeexpectedifthepatient’slungarebeingmechanicallyventilated.

• Theshapeofthecentralvenouswaveformcorrespondstotheeventsofthecardiaccontractions.


CVPWaveform• Thenormalwaveformconsistsofthreepeaksandtwodescents.

• Thea- waveisatrialcontraction(theseareabsentinatrialfibrillation).

• Thecwavesareduetotricuspidvalveelevationduringearlyventricularcontraction

• Thev-wavereflectvenousreturnagainstaclosedtricuspidvalve.

• Thetwodescents(xandy)areduetothedownwarddisplacementofthetricuspidvalveduringsystoleandtricuspidvalveopeningduringdiastole.

CVPWaveform• Threepeak(a,c,andv

waves)andtwodescents(x,y)canbeseeninanormalCVPwaveform.

• Ifawavesareabsent,thepwaveisabsentonECGtracing

• Largeawavesarepresentswhenresistancetoemptyingoftherightatriumispresent(i.e.tricuspidstenosisorpulmonaryhypertension)

• Alargevwavemaysuggesttricuspidregurgitation

MorganGE.MikhailMS.MurrayMJ.ClinicalAnesthesiology(4th ed.).Ch.6.PatientMonitors.,NewYork,2006

ElevatedCVP• TricupsidStenosis• TricupsidRegurgitation• PulmonaryHypertension• MitralStenosis• MitralRegurgitation• LVFailure• VolumeOverload• CardiacTamponade• Arrhythmias• IncreasedPVR(Anxiety,Pain)

ComplicationsofCVCPlacement

• Arterialpuncture• Pneumothorax• Chylothorax• TrachealInjury• CardiacTamponade• Arrhythmias• Airembolus• Thrombosis• Infection

PulmonaryArteryCatheterization(PAC)

• Flow-directed,balloon-tippedcatheter

• Allowsforcatheterizationofrightheartformeasurementofpressures

• Pulmonaryarteryocclusion(wedge)reflectsleftatrialpressure

• Samplingmixedvenousblood

• Thermistorattipofcathetermeasurestemperatureofbloodflowingpast

PulmonaryArteryCatheterization• Theeffectivenessofpulmonaryarterycatheter(PAC)monitoring

remainslargelyunproveninmanygroupsofsurgicalpatient.• TheAmericanSocietyofAnesthesiology(ASA)concludesthatthe

appropriatenessofPACdependsonthecombinationofrisksassociatedwiththepatient.

• MonitoringPAPandcardiacoutputincriticallyillpatientshasbeenshowntoprovidecardiovascularinformationthatismoreaccuratethanthatobtainedbyclinicalassessment.

• Thesemeasurementsproveparticularlyimportantinpatientsathighriskforhemodynamicinstability(e.g.recentM.I.orTAAA).

• WhenPAOPoccurs,thereisnobloodflow,thepressurescanequilibratebetweenthedistalendofthepulmonaryarterycatheterandtheleftatrium.

MorganGE.MikhailMS.MurrayMJ.ClinicalAnesthesiology(4th ed.).Ch.6.PatientMonitors.,NewYork,2006

PACIndications

• Poorleftventricularfuction (EF<40%)• Assessmentofintravascularfluidvolume• Valvular heartdiseases• ResponsetoIVfluidinfusionoradministrationofdrugs(vasopressors,vasodilators,intropes)

• Recentmyocardialinfarction• Massivetrauma(shock,hemorrhage)• Majorvascularsurgery(cross-clampingoftheaorta,largefluidshifts)

TypesofSwans

• Paceport – capableofprovidingcardiacpacing

• ContinuousCardiacOutput– producesathermodilution curvetodeterminecardiacoutput

• MixedvenousO2- candeterminevenousoxygensaturationwhenthereisadecreaseintissuebloodfloworO2 delivery

• Heparin vs Un-heparincoated

ContraindicationstoPAC• Relative

– Surgicalfield– Leftbundlebranchblock– Traumatizedtissue– Coagulopathy– Mitraloraorticvalvular stenosis

• Absolute– Pulmonaryvalvestenosis– ArtificialorProstheticRightSidedValves– PatientRefusal– Infectionatthelocalsite

PACWaveform


ComplicationsforPACPlacement

• Dysrhythmias• Rightventriculardamage• Pulmonaryarteryrupture• Pulmonaryinfarction• Thrombosis• Infection• Intracardiac knotformation

ElevatedPAP

• PulmonaryHypertension• IncreasePVR(i.e.drugs,COPD)• LeftHeartFailure• MitralStenosis• MitralRegurgitation• CardiacTamponade• Arrhythmias

PACUsedtoEvaluateHemodynamicDisorders

CVP PAOP PAEDP

Hypovolemia Decreased Decreased PAEDP=PAOP

Left ventricular failure

Increased Increased PAEDP=PAOP

Right ventricular failure

Increased No change PAEDP=PAOP

Pulmonary embolism

Increased No change PAEDP>PAOP

Cardiac Tamponade

Increased Increased PAEDP=PAOP

Transesophageal Echocardiography(TEE)

• GreatadvantageoverPAC• Usedtocharacterizecardiacvalvemorphologyandfunction

• Determineregionalwallmotionabnormalities(myocardialischemia)

• Assesscardiacoutput• Adequacyofintravascularfluidvolume• LessinvasivethanPAC

HemodynamicVariables

• CalculatingSystemicVascularResistance

Recall,V=I*R

SVR=(MAP– CVP)*80______________

C.O.

Normally, SVR = 1200-1500 dynes*s*cm-5

MoreHemodynamicVariables

• CalculatePulmonaryVascularResistance(PVR)

PVR=(MPAP– PAOP)*80_________________

C.O.

Normally, PVR = 100-300 dynes*s*cm-5

PreloadandCardiacPerformance

• Greenline– Venodilatortherapydecreasespreloadandinotropictherapyincreasescardiacindex(theheartmovesupwardandtotheleftonthecurve)

• Yellowline– Theventricularfunction(Starling)curveofthenormalleftventricularisaffectedmuchmorebychangesinpreloadthanitisbyanincreaseinafterload

• Redline– thefailingheartmovestoacurvedownwardandtotherightofthenormalheart


FickPrincipleTheamountofoxygenconsumedbyanindividualequalsthedifferencebetweenarterialandvenousoxygencontentmultiplebycardiacoutput.

C.O.=O2 consumptiona-vO2 contentdifference

C.O.=VO2_________________CaO2 – CvO2

TheEnd

hemodynamic monitoring · 2019-08-09 · intra-arterial blood pressure indications • beat-to-beat...

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